Shallow seismic structure of Kunlun fault zone in northern Tibetan Plateau, China: Implications for the 2001 M s8.1 Kunlun earthquake

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Wang, Chun-Yong; Mooney, W.D.; Ding, Z.; Yang, J.; Yao, Z.; Lou, H.

2009-01-01

The shallow seismic velocity structure of the Kunlun fault zone (KLFZ) was jointly deduced from seismic refraction profiling and the records of trapped waves that were excited by five explosions. The data were collected after the 2001 Kunlun M s8.1 earthquake in the northern Tibetan Plateau. Seismic phases for the in-line record sections (26 records up to a distance of 15 km) along the fault zone were analysed, and 1-D P- and S-wave velocity models of shallow crust within the fault zone were determined by using the seismic refraction method. Sixteen seismic stations were deployed along the off-line profile perpendicular to the fault zone. Fault-zone trapped waves appear clearly on the record sections, which were simulated with a 3-D finite difference algorithm. Quantitative analysis of the correlation coefficients of the synthetic and observed trapped waveforms indicates that the Kunlun fault-zone width is 300 m, and S-wave quality factor Q within the fault zone is 15. Significantly, S-wave velocities within the fault zone are reduced by 30-45 per cent from surrounding rocks to a depth of at least 1-2 km, while P-wave velocities are reduced by 7-20 per cent. A fault-zone with such P- and S-low velocities is an indication of high fluid pressure because Vs is affected more than Vp. The low-velocity and low-Q zone in the KLFZ model is the effect of multiple ruptures along the fault trace of the 2001 M s8.1 Kunlun earthquake. ?? 2009 The Authors Journal compilation ?? 2009 RAS.

Implications of Zn/Fe ratios for the sources of Colorado Plateau basalts

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Rudzitis, S.; Reid, M. R.

2011-12-01

Early Miocene to recent mafic magmatism migrated across the Arizona Transition Zone towards the center of the stable Colorado Plateau at a rate of ~ 3-6 km/Myr (Roy et al., 2009). Present-day volcanic centers are close to a stepwise change in the thickness of the lithosphere between the Colorado Plateau and Basin and Range. Accordingly, volcanic migration might track progressive thinning of the lithosphere towards the center of the Colorado Plateau. This project aims to determine the conditions of melt generation across the transition zone in order to investigate the temporal/spatial correlation between volcanism and thinning of the Colorado Plateau lithosphere. Pressure and temperature estimates for Colorado Plateau basalts can be obtained from the Mg and Si contents of melts (Lee et al, 2009) but require melting of a peridotitic source. Eclogite and pyroxenite xenoliths reported in Colorado Plateau basalts show that melt sources could be olivine-poor. Zn/Fe ratios in melts can help to distinguish contributions from olivine-poor sources because they are sensitive to differences in bulk chemistry and to mineralogy (Le Roux et al., 2010). Specifically, Zn/Fe is not fractionated between melt, olivine, and orthopyroxene, but is highly fractionated when clinopyroxene and garnet are present. Our work to date has focused on laser ablation-IC-PMS analysis of individual olivine grains from high-Mg basalts (>8.0 wt. %) from the San Francisco and Mormon Mountain volcanic fields. Preliminary values of Zn/Fe ratios that represent the averages of multiple analyses of several grains in individual samples range from 7.9 to 9.3 (x10000). Variations of up to 1.7 (x10000) in the ratios exist between individual grains within samples and could be the result of co-crystallization of clinopyroxene with olivine. The lowest values in each sample should approach the Zn/Fe ratios of parental melts, and are, in turn, similar to MORB values and predicted peridotite melts. The results suggest

Interactions between ecosystems and hydrology in the Loess Plateau

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Fu, B.; Wang, S.

2017-12-01

The Loess Plateau is located in the arid and semi-arid temperate continental monsoon climatic zone. Large-scale "Grain-for-Green" project has been implemented in the since 1999, which has made remarkable contribution to the soil and water control, but also has led to some negative ecological effects. Understanding the interactions between ecosystems and hydrology is significant for the vegetation carrying capacity assessment and guiding the vegetation restoration. We observed the soil moisture at multiple scales including slope, catchment and transect across Loess Plateau to analyze the effects of land use change and its trend along the precipitation gradient. Remote sensing data also used to capture the spatiotemporal variance of soil moisture in the Loess Plateau, as well as the in-situ measured soil moisture decrease following the massive re-vegetation. We found soil moisture decrease in response to the massive re-vegetation occurred in a transition zone of grass-forest ecosystems with annual precipitation between 450-550 mm. The average runoff in the Loess Plateau also decreased continuously during the period 1961-2009 (average rate of -0.9 mm yr-1, P < 0.001). Human intervention played a dominant role in creating the transition points, Water yield (i.e., the ratio of runoff to precipitation) decreased following each anthropogenic transition, causing a 56% reduction in available freshwater resources during the period 1961-2009. From currently revegetated areas and human water demand, we estimate a threshold of NPP of 400±5 g C m-2 yr-1 above which the population will suffer water shortages. NPP in this region is found to be already close to this limit.

Are the Columbia River Basalts, Columbia Plateau, Idaho, Oregon, and Washington, USA, a viable geothermal target? A preliminary analysis

Science.gov (United States)

Burns, Erick R.; Williams, Colin F.; Tolan, Terry; Kaven, Joern Ole

2016-01-01

The successful development of a geothermal electric power generation facility relies on (1) the identification of sufficiently high temperatures at an economically viable depth and (2) the existence of or potential to create and maintain a permeable zone (permeability >10-14 m2) of sufficient size to allow efficient long-term extraction of heat from the reservoir host rock. If both occur at depth under the Columbia Plateau, development of geothermal resources there has the potential to expand both the magnitude and spatial extent of geothermal energy production. However, a number of scientific and technical issues must be resolved in order to evaluate the likelihood that the Columbia River Basalts, or deeper geologic units under the Columbia Plateau, are viable geothermal targets.Recent research has demonstrated that heat flow beneath the Columbia Plateau Regional Aquifer System may be higher than previously measured in relatively shallow (characteristic of natural hydrothermal reservoirs. From a hydraulic perspective, Columbia River Basalts are typically divided into dense, impermeable flow interiors and interflow zones comprising the top of one flow, the bottom of the overlying flow, and any sedimentary interbed. Interflow zones are highly variable in texture but, at depths 10-14 m2) interflows are documented at depths up to ~1,400 m. If the elevated permeability in these zones persists to greater depths, they may provide natural permeability of sufficient magnitude to allow their exploitation as conventional geothermal reservoirs. Alternatively, if the permeability in these interflow zones is less than 10-14 m2 at depth, it may be possible to use hydraulic and thermal stimulation to enhance the permeability of both the interflow zones and the natural jointing within the low-permeability interior portions of individual basalt flows in order to develop Enhanced/Engineered Geothermal System (EGS) reservoirs. The key challenge for an improved Columbia Plateau

Spatial variation in the storages and age-related dynamics of forest carbon sequestration in different climate zones-evidence from black locust plantations on the Loess Plateau of China.

Science.gov (United States)

Li, Taijun; Ren, Bowen; Wang, Dahui; Liu, Guobin

2015-01-01

Knowledge about the long-term influences of climate change on the amount of potential carbon (C) sequestration in forest ecosystems, including age-related dynamics, remains unclear. This study used two similar age-sequences of black locust forests (Robinia pseudoacacia L.) in the semi-arid and semi-humid zones of China's Loess Plateau to assess the variation in C stocks and age-related dynamics. Our results demonstrated that black locust forests of the semi-humid zone stored significantly more C than did forests in the semi-arid zone, across the chronosequence (p zone, while the semi-arid zone had a capacity of only 79.4 Mg C ha-1. Soil organic C (SOC) increased continuously with stand age in the semi-arid zone (R2 = 0.84, p = 0.010). However, in the semi-humid zone, SOC declined sharply by 47.8% after the initial stage (5 to 10 y). The C stock in trees increased continuously with stand age in the semi-humid zone (R2 = 0.83, p = 0.011), yet in the semi-arid zone, it decreased dramatically from 43.0 Mg C ha-1 to 28.4 Mg C ha-1 during the old forest stage (38 to 56 y). The shift from being a net C sink to a net C source occurred at the initial stage in the semi-humid zone versus at the old forest stage in the semi-arid zone after reforestation. Surprisingly, with the exception of the initial and later stages (55 y), the patterns of C allocation among trees, soils, understory and litter were not statistically different between the two climate zones. Our results suggest that climate factors can alter the potential amount and age-related dynamics of forest C sequestration.

Geodynamics of oceanic plateau and plume head accretion and their role in Phanerozoic orogenic systems of China

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Peter G. Betts

2015-01-01

Full Text Available We present three 3D numerical models of deep subduction where buoyant material from an oceanic plateau and a plume interact with the overriding plate to assess the influence on subduction dynamics, trench geometry, and mechanisms for plateau accretion and continental growth. Transient instabilities of the convergent margin are produced, resulting in: contorted trench geometry; trench migration parallel with the plate margin; folding of the subducting slab and orocline development at the convergent margin; and transfer of the plateau to the overriding plate. The presence of plume material beneath the oceanic plateau causes flat subduction above the plume, resulting in a “bowed” shaped subducting slab. In plateau-only models, plateau accretion at the edge of the overriding plate results in trench migration around the edge of the plateau before subduction is re-established directly behind the trailing edge of the plateau. The plateau shortens and some plateau material subducts. The presence of buoyant plume material beneath the oceanic plateau has a profound influence on the behaviour of the convergent margin. In the plateau + plume model, plateau accretion causes rapid trench advance. Plate convergence is accommodated by shearing at the base of the plateau and shortening in the overriding plate. The trench migrates around the edge of the plateau and subduction is re-established well behind the trailing edge of the plateau, effectively embedding the plateau into the overriding plate. A slab window forms beneath the accreted plateau and plume material is transferred from the subducting plate to the overriding plate through the window. In all of the models, the subduction zone maintains a relatively stable configuration away from the buoyancy anomalies within the downgoing plate. The models provide a dynamic context for plateau and plume accretion in Phanerozoic accretionary orogenic systems such as the East China Orogen and the Central Asian

Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

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Jiren Xu

2009-01-01

Full Text Available Various earthquake fault types, mechanism solutions and stress fields, as well as GPS and geothermal data are analyzed for the study of the crustal movements on the Tibetan plateau and their tectonic implications. The results show that a lot of the normal faulting type-event concentrated at altitudes greater than 4000 m on the central Tibetan plateau. The altitudes concentrating normal faulting type-events can be zoned two parts: the western part, the Lhasa block, and the eastern part, the Qiangtang-Changdu region. The azimuths of T-axes are in a general E-W direction in the Lhasa block and NW-SE or NNW-SSE in the Qiangtang-Changdu region at the altitudes of the Tibetan plateau. The tensional stresses in E-W direction and NW-SE direction predominate normal faulting earthquake occurrence in the Lhasa block and the Qiangtang-Changdu region, respectively. The slipping displacements of the normal-faulting-type events have great components in near E-W direction and NW-SE direction in the Lhasa block and the Qiangtang-Changdu region, respectively. The extensions are probably an eastward or southeastward extensional motion, being mainly tectonic activity phenomena in the plateau altitudes. The extensional motions due to normal-fault earthquakes are important tectonic activity regimes on the high altitudes of the plateau. The easterly crustal extensions on the plateau are attributable to the gravitational collapse of the high plateau and eastward extrusion of hotter mantle materials beneath the eastern boundary of the plateau. Numbers of thrust-fault and strike-slip-fault earthquakes with strong compressive stress in a general NNE-SSW direction occur on the edges of the plateau.

Tectonic History and Deep Structure of the Demerara Plateau from Combined Wide-Angle and Reflection Seismic Data and Plate Kinematic Reconstructions

Science.gov (United States)

Klingelhoefer, F.; Museur, T.; Roest, W. R.; Graindorge, D.; Chauvet, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Lebrun, J. F.; Perrot, J.; Heuret, A.

2017-12-01

Many transform margins have associated intermediate depth marginal plateaus, which are commonly located between two oceanic basins. The Demerara plateau is located offshore Surinam and French Guiana. Plate kinematic reconstructions show that the plateau is located between the central and equatorial Atlantic in a position conjugate to the Guinean Plateau. In the fall of 2016, the MARGATS cruise acquired geophysical data along the 400 km wide Demerara plateau. The main objective of the cruise was to image the deep structure of the Demerara plateau and to study its tectonic history. A set of 4 combined wide-angle and reflection seismic profiles was acquired along the plateau, using 80 ocean-bottom seismometers, a 3 km long seismic streamer and a 8000 cu inch tuned airgun array. Forward modelling of the wide-angle seismic data on a profile, located in the eastern part of the plateau and oriented in a NE-SW direction, images the crustal structure of the plateau, the transition zone and the neighbouring crust of oceanic origin, up to a depth of 40 km. The plateau itself is characterised by a crust of 30 km thickness, subdivided into three distinct layers. However, the velocities and velocity gradients do not fit typical continental crust, with a lower crustal layer showing untypically high velocities and an upper layer having a steep velocity gradient. From this model we propose that the lowermost layer is probably formed from volcanic underplated material and that the upper crustal layer likely consists of the corresponding extrusive volcanic material, forming thick seaward-dipping reflector sequences on the plateau. A basement high is imaged at the foot of the slope and forms the ocean-continent transition zone. Further oceanward, a 5-6 km thick crust is imaged with velocities and velocity gradients corresponding to a thin oceanic crust. A compilation of magnetic data from the MARGATS and 3 previous cruises shows a high amplitude magnetic anomaly along the northern

Sources, atmospheric transport and deposition mechanism of organochlorine pesticides in soils of the Tibetan Plateau.

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Chen, Laiguo; Feng, Qianhua; He, Qiusheng; Huang, Yumei; Zhang, Yu; Jiang, Guo; Zhao, Wei; Gao, Bo; Lin, Kui; Xu, Zhencheng

2017-01-15

Because of mountain cold-trapping, the soil in the Tibetan Plateau may be an important global sink of organochlorine pesticides (OCPs). However, there are limited data on OCPs in the soils of the Tibetan Plateau. In addition, the atmospheric transport and deposition mechanisms of OCPs also need to be further studied. In this study, the sampling area covered most regions of the Tibetan Plateau. The detection frequencies of ΣChlordane (sum of trans-chlordane, cis-chlordane and oxychlordane), HCB, ΣNonachlor (sum of trans- and cis-nonachlor), DDTs, ΣEndo (sum of endosulfan-I, endosulfan-II and endosulfate), aldrin, HCHs, ΣHeptachlor (sum of heptachlor and heptachlor epoxide), mirex and dieldrin were 100%, 98.3%, 96.6%, 94.8%, 89.7%, 87.9%, 62.1%, 55.2%, 32.8% and 6.9%, respectively. DDTs (with arithmetic mean values of 1050ngkg -1 dw) and HCHs (393ngkg -1 ) were the principal OCPs in cultivated soils, whereas ΣEndo (192ngkg -1 ) and ΣChlordane (152ngkg -1 ) were the principal OCPs in non-cultivated soils. Local use of DDTs, dicofol and HCHs may be an important source of OCP accumulation in the soil of the Tibetan Plateau. Aldrin and endosulfan are considered to be good indicators for studying atmospheric transport and deposition of OCPs from South Asia and Southeast Asia. Two zones with high OCP levels were found in the southeast and northwest of the Tibetan Plateau. The zones have dissimilar pollution sources of OCPs and are influenced by different factors that affect their precipitation scavenging efficiency. The amount of precipitation was the dominant factor in the southeast, whereas large differences in temperature and wind speed were the dominant factors in the northwest. Copyright © 2016 Elsevier B.V. All rights reserved.

Morphotectonics of a high plateau on the northwestern flank of the Continental Rift of southeastern Brazil

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Modenesi-Gauttieri, May Christine; Takashi Hiruma, Silvio; Riccomini, Claudio

2002-03-01

Integration of landform and structural analysis allowed the identification of Late Pleistocene-Holocene pulses of tectonic activity in the Campos do Jordão Plateau with ages and regimes similar to the ones from the continental rift. Fault reactivation along Precambrian shear zones give rise to a series of conspicuous morphotectonic features, determine the formation of stream piracy phenomena, and divide the plateau into smaller blocks. Recognition of these tectonic pulses as well as of their effects in landform development—particularly clear on the Campos de São Francisco at the highest area of the SE edge of the plateau—show that besides the climate-related Quaternary environmental changes significant neotectonic instability should be considered in the geomorphic evolution of the Campos do Jordão Plateau.

Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau.

Science.gov (United States)

Li, Qiang; Wang, Xiaoming

2015-01-01

This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an "out of Tibet" hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an "into Tibet" scenario--earlier and more primitive taxa originated from outside of the Tibetan Plateau and the

Earthquake Clusters and Spatio-temporal Migration of earthquakes in Northeastern Tibetan Plateau: a Finite Element Modeling

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Sun, Y.; Luo, G.

2017-12-01

Seismicity in a region is usually characterized by earthquake clusters and earthquake migration along its major fault zones. However, we do not fully understand why and how earthquake clusters and spatio-temporal migration of earthquakes occur. The northeastern Tibetan Plateau is a good example for us to investigate these problems. In this study, we construct and use a three-dimensional viscoelastoplastic finite-element model to simulate earthquake cycles and spatio-temporal migration of earthquakes along major fault zones in northeastern Tibetan Plateau. We calculate stress evolution and fault interactions, and explore effects of topographic loading and viscosity of middle-lower crust and upper mantle on model results. Model results show that earthquakes and fault interactions increase Coulomb stress on the neighboring faults or segments, accelerating the future earthquakes in this region. Thus, earthquakes occur sequentially in a short time, leading to regional earthquake clusters. Through long-term evolution, stresses on some seismogenic faults, which are far apart, may almost simultaneously reach the critical state of fault failure, probably also leading to regional earthquake clusters and earthquake migration. Based on our model synthetic seismic catalog and paleoseismic data, we analyze probability of earthquake migration between major faults in northeastern Tibetan Plateau. We find that following the 1920 M 8.5 Haiyuan earthquake and the 1927 M 8.0 Gulang earthquake, the next big event (M≥7) in northeastern Tibetan Plateau would be most likely to occur on the Haiyuan fault.

Tirapazamine vs carbogen and nicotinamide with fractionated irradiation. What is the optimum time of giving tirapazamine during the course of irradiation?

International Nuclear Information System (INIS)

Elsaid, A.A.; Menke, D.; Dorie, M.J.; Brown, J.M.

1996-01-01

Purpose: 1) To compare in a fractionated regimen, with clinically relevant radiation doses, using human tumor xenografts, two radiation response modifiers that function by different mechanisms: A) Tirapazamine (TPZ), a bioreductive drug of the benzotriazine-di-N-oxide class which shows a highly selective cytotoxicity for hypoxic cells. B) Nicotinamide (NAM), an amide of vitamin B 3 , with Carbogen breathing (CBG), a combination that has been shown to reduce both acute (perfusion-limited) hypoxia and chronic (diffusion-limited) hypoxia. 2) To determine the optimum time of giving TPZ during the course of irradiation (XRT). Materials and Methods: Cell survival assays were used to examine the response of two different human tumor xenografts: FaDu, a carcinoma of the head and neck, and HT29, a colon carcinoma, in SCID mice. Growth delay studies were performed with the FaDu tumor to compare the following treatments: TPZ with XRT, NAM + CBG with XRT, and TPZ + NAM + CBG with XRT. Clinical phase I studies of TPZ have been completed and suggest that a fractionated course of 3 fractions/week of TPZ is tolerable at an effective cytotoxic dose. However, if hypoxic cells are present in the tumor on the days that TPZ is not given (i.e. rehypoxiation has occurred) then this will reduce the effectiveness of the drug-radiation combination. To investigate this we have given CBG and NAM on the days TPZ is not given with fractionated irradiation. The fractionated irradiation schedule consisted of 2.0 or 2.5 Gy once or twice daily for one or two weeks with and without drug pre treatment. TPZ was given i.p. at 0.08 mmol/kg 30 min before irradiation for the whole course, or for 3 fractions per week alone, or with 2 fractions per week of NAM and CBG. NAM was given i.p. at 1000 mg/kg, 1 hr prior to irradiation, with CBG exposure 5 min. prior to and during the irradiation. Another growth delay study is being performed to investigate which schedule produces the most enhancement: TPZ during

Genetic diversity and sex-bias dispersal of plateau pika in Tibetan plateau.

Science.gov (United States)

Zhang, Liangzhi; Qu, Jiapeng; Li, Kexin; Li, Wenjing; Yang, Min; Zhang, Yanming

2017-10-01

Dispersal is an important aspect in organism's life history which could influence the rate and outcome of evolution of organism. Plateau pika is the keystone species in community of grasslands in Tibetan Plateau. In this study, we combine genetic and field data to character the population genetic pattern and dispersal dynamics in plateau pika ( Ochotona curzoniae ). Totally, 1,352 individual samples were collected, and 10 microsatellite loci were analyzed. Results revealed that plateau pika possessed high genetic diversity and inbreeding coefficient in a fine-scale population. Dispersal distance is short and restricted in about 20 m. An effective sex-biased dispersal strategy is employed by plateau pika: males disperse in breeding period for mating while females do it after reproduction for offspring and resource. Inbreeding avoiding was shown as the common driving force of dispersal, together with the other two factors, environment and resource. In addition, natal dispersal is female biased. More detailed genetic analyzes are needed to confirm the role of inbreeding avoidance and resource competition as ultimate cause of dispersal patterns in plateau pika.

Spatial variation in the storages and age-related dynamics of forest carbon sequestration in different climate zones-evidence from black locust plantations on the Loess Plateau of China.

Directory of Open Access Journals (Sweden)

Taijun Li

Full Text Available Knowledge about the long-term influences of climate change on the amount of potential carbon (C sequestration in forest ecosystems, including age-related dynamics, remains unclear. This study used two similar age-sequences of black locust forests (Robinia pseudoacacia L. in the semi-arid and semi-humid zones of China's Loess Plateau to assess the variation in C stocks and age-related dynamics. Our results demonstrated that black locust forests of the semi-humid zone stored significantly more C than did forests in the semi-arid zone, across the chronosequence (p < 0.001. The C carrying capacity of the plantations was measured at 166.4 Mg C ha-1 (1 Mg = 106 g in the semi-humid zone, while the semi-arid zone had a capacity of only 79.4 Mg C ha-1. Soil organic C (SOC increased continuously with stand age in the semi-arid zone (R2 = 0.84, p = 0.010. However, in the semi-humid zone, SOC declined sharply by 47.8% after the initial stage (5 to 10 y. The C stock in trees increased continuously with stand age in the semi-humid zone (R2 = 0.83, p = 0.011, yet in the semi-arid zone, it decreased dramatically from 43.0 Mg C ha-1 to 28.4 Mg C ha-1 during the old forest stage (38 to 56 y. The shift from being a net C sink to a net C source occurred at the initial stage in the semi-humid zone versus at the old forest stage in the semi-arid zone after reforestation. Surprisingly, with the exception of the initial and later stages (55 y, the patterns of C allocation among trees, soils, understory and litter were not statistically different between the two climate zones. Our results suggest that climate factors can alter the potential amount and age-related dynamics of forest C sequestration.

Spatio-Temporal Characteristics of Global Warming in the Tibetan Plateau during the Last 50 Years Based on a Generalised Temperature Zone - Elevation Model

Science.gov (United States)

Wei, Yanqiang; Fang, Yiping

2013-01-01

Temperature is one of the primary factors influencing the climate and ecosystem, and examining its change and fluctuation could elucidate the formation of novel climate patterns and trends. In this study, we constructed a generalised temperature zone elevation model (GTEM) to assess the trends of climate change and temporal-spatial differences in the Tibetan Plateau (TP) using the annual and monthly mean temperatures from 1961–2010 at 144 meteorological stations in and near the TP. The results showed the following: (1) The TP has undergone robust warming over the study period, and the warming rate was 0.318°C/decade. The warming has accelerated during recent decades, especially in the last 20 years, and the warming has been most significant in the winter months, followed by the spring, autumn and summer seasons. (2) Spatially, the zones that became significantly smaller were the temperature zones of −6°C and −4°C, and these have decreased 499.44 and 454.26 thousand sq km from 1961 to 2010 at average rates of 25.1% and 11.7%, respectively, over every 5-year interval. These quickly shrinking zones were located in the northwestern and central TP. (3) The elevation dependency of climate warming existed in the TP during 1961–2010, but this tendency has gradually been weakening due to more rapid warming at lower elevations than in the middle and upper elevations of the TP during 1991–2010. The higher regions and some low altitude valleys of the TP were the most significantly warming regions under the same categorizing criteria. Experimental evidence shows that the GTEM is an effective method to analyse climate changes in high altitude mountainous regions. PMID:23565182

Tibial Plateau Fractures

DEFF Research Database (Denmark)

Elsøe, Rasmus

This PhD thesis reported an incidence of tibial plateau fractures of 10.3/100,000/year in a complete Danish regional population. The results reported that patients treated for a lateral tibial plateau fracture with bone tamp reduction and percutaneous screw fixation achieved a satisfactory level...... with only the subgroup Sport significantly below the age matched reference population. The thesis reports a level of health related quality of life (Eq5d) and disability (KOOS) significantly below established reference populations for patients with bicondylar tibial plateau fracture treated with a ring...... fixator, both during treatment and at 19 months following injury. In general, the thesis demonstrates that the treatment of tibial plateau fractures are challenging and that some disabilities following these fractures must be expected. Moreover, the need for further research in the area, both with regard...

U Plant Geographic Zone Cleanup Prototype

International Nuclear Information System (INIS)

Romine, L.D.; Leary, K.D.; Lackey, M.B.; Robertson, J.R.

2006-01-01

The U Plant geographic zone (UPZ) occupies 0.83 square kilometers on the Hanford Site Central Plateau (200 Area). It encompasses the U Plant canyon (221-U Facility), ancillary facilities that supported the canyon, soil waste sites, and underground pipelines. The UPZ cleanup initiative coordinates the cleanup of the major facilities, ancillary facilities, waste sites, and contaminated pipelines (collectively identified as 'cleanup items') within the geographic zone. The UPZ was selected as a geographic cleanup zone prototype for resolving regulatory, technical, and stakeholder issues and demonstrating cleanup methods for several reasons: most of the area is inactive, sufficient characterization information is available to support decisions, cleanup of the high-risk waste sites will help protect the groundwater, and the zone contains a representative cross-section of the types of cleanup actions that will be required in other geographic zones. The UPZ cleanup demonstrates the first of 22 integrated zone cleanup actions on the Hanford Site Central Plateau to address threats to groundwater, the environment, and human health. The UPZ contains more than 100 individual cleanup items. Cleanup actions in the zone will be undertaken using multiple regulatory processes and decision documents. Cleanup actions will include building demolition, waste site and pipeline excavation, and the construction of multiple, large engineered barriers. In some cases, different cleanup actions may be taken at item locations that are immediately adjacent to each other. The cleanup planning and field activities for each cleanup item must be undertaken in a coordinated and cohesive manner to ensure effective execution of the UPZ cleanup initiative. The UPZ zone cleanup implementation plan (ZCIP) [1] was developed to address the need for a fundamental integration tool for UPZ cleanup. As UPZ cleanup planning and implementation moves forward, the ZCIP is intended to be a living document that will

PLATEAU IRIS SYNDROME--CASE SERIES.

Science.gov (United States)

Feraru, Crenguta Ioana; Pantalon, Anca Delia; Chiselita, Dorin; Branisteanu, Daniel

2015-01-01

Plateau iris is characterized by closing the anterior chamber angle due to a large ciliary body or due to its anterior insertion that alters the position of iris periphery in respect to the trabecular meshwork. There are two aspects that need to be differentiated: plateau iris configuration and plateau iris syndrome. The first describes a situation when the iris root is flat and the anterior chamber is not shallow, the latter refers to a post laser iridotomy condition in which a patent iridotomy has removed the relative pupillary block, but goniscopically confirmed angle closure recurs without central shallowing of the anterior chamber. Isolated plateau iris syndrome is rare compared to plateau iris configuration. We hereby present two case reports of plateau iris syndrome in young patients who came to an ophthalmologic consult by chance.

Blending Satellite Observed, Model Simulated, and in Situ Measured Soil Moisture over Tibetan Plateau

Directory of Open Access Journals (Sweden)

Yijian Zeng

2016-03-01

Full Text Available The inter-comparison of different soil moisture (SM products over the Tibetan Plateau (TP reveals the inconsistency among different SM products, when compared to in situ measurement. It highlights the need to constrain the model simulated SM with the in situ measured data climatology. In this study, the in situ soil moisture networks, combined with the classification of climate zones over the TP, were used to produce the in situ measured SM climatology at the plateau scale. The generated TP scale in situ SM climatology was then used to scale the model-simulated SM data, which was subsequently used to scale the SM satellite observations. The climatology-scaled satellite and model-simulated SM were then blended objectively, by applying the triple collocation and least squares method. The final blended SM can replicate the SM dynamics across different climatic zones, from sub-humid regions to semi-arid and arid regions over the TP. This demonstrates the need to constrain the model-simulated SM estimates with the in situ measurements before their further applications in scaling climatology of SM satellite products.

Seroprevalence of Capripoxvirus infection in sheep and goats among different agro-climatic zones of Odisha, India.

Science.gov (United States)

Hota, Abhishek; Biswal, Sangram; Sahoo, Niranjana; Venkatesan, Gnanavel; Arya, Sargam; Kumar, Amit; Ramakrishnan, Muthannan Andavar; Pandey, Awadh Bihari; Rout, Manoranjan

2018-01-01

The study was undertaken to assess the prevalence of antibodies to Capripoxviruses among small ruminants of Odisha, India. A total of 500 random serum samples collected from 214 sheep and 286 goats across 10 agro-climatic zones of Odisha, were screened using whole virus antigen-based indirect ELISA for antibodies against Capripoxviruses. Results were analyzed by suitable statistical methods. Screening of 500 serum samples showed seropositivity of 8.88% and 31.47% in sheep and goats, respectively, for Capripoxviruses. The prevalence rate according to agro-climatic zone ranged from 0% (North Eastern coastal plain zone) to 48.57% (North central plateau zone) for goat pox, and 0% (Western undulating zone and North central plateau) to 22.22% (South Eastern ghat zone) for sheep pox. The difference in prevalence rates among the various agro-climatic zones was statistically significant (ppox and Dhenkanal (80%) for goat pox. The study revealed serological evidence of Capripoxvirus infection in sheep and goat populations in the study area, in the absence of vaccination. Systematic investigation, monitoring, and reporting of outbreaks are necessary to devise control strategies.

Heterogeneity in Subducting Slab Influences Fluid Properties, Plate Coupling and Volcanism: Hikurangi Subduction Zone, New Zealand

Science.gov (United States)

Eberhart-Phillips, D. M.; Reyners, M.; Bannister, S. C.

2017-12-01

Seismicity distribution and 3-D models of P- and S-attenuation (1/Q) in the Hikurangi subduction zone, in the North Island of New Zealand, show large variation along-arc in the fluid properties of the subducting slab. Volcanism is also non-uniform, with extremely productive rhyolitic volcanism localized to the central Taupo Volcanic zone, and subduction without volcanism in the southern North Island. Plate coupling varies with heterogeneous slip deficit in the northern section, low slip deficit in the central section, and high slip deficit (strong coupling) in the south. Heterogeneous initial hydration and varied dehydration history both are inferred to play roles. The Hikurangi Plateau (large igneous province) has been subducted beneath New Zealand twice - firstly at ca. 105-100 Ma during north-south convergence with Gondwana, and currently during east-west convergence between the Pacific and Australian plates along the Hikurangi subduction zone. It has an uneven downdip edge which has produced spatially and temporally localized stalls in subduction rate. The mantle wedge under the rhyolitic section has a very low Q feature centred at 50-125 km depth, which directly overlies a 150-km long zone of dense seismicity. This seismicity occurs below a sharp transition in the downdip extent of the Hikurangi Plateau, where difficulty subducting the buoyant plateau would have created a zone of increased faulting and hydration that spent a longer time in the outer-rise yielding zone, compared with areas to the north and south. At shallow depths this section has unusually high fracture permeability from the two episodes of bending, but it did not experience dehydration during Gondwana subduction. This central section at plate interface depths less than 50-km has low Q in the slab crust, showing that it is extremely fluid rich, and it exhibits weak plate coupling with both deep and shallow slow-slip events. In contrast in the southern section, where there is a large deficit in

Seismic observation of a sharp post-garnet phase transition within the Farallon crust: Evidence for oceanic plateau subduction

Science.gov (United States)

Maguire, R.; Ritsema, J.

2017-12-01

The tectonic evolution of North America over the past 150 million years was heavily influenced by the complex subduction history of the Farallon plate. In particular, Laramide mountain building may have been triggered by the initiation of flat slab subduction in the late Cretaceous. While it has been proposed that the cause of slab flattening is related to the subduction of an oceanic plateau[1], direct geophysical evidence of a subducted oceanic plateau is lacking. Here, using P-to-S receiver functions, we detect a sharp seismic discontinuity at 720-km depth beneath the southeastern United States and Gulf of Mexico. We interpret this discontinuity as a garnet-to-bridgmanite phase transition occurring within a thickened Farallon crust. Our results are consistent with a subducted oceanic plateau (likely the conjugate half of the Hess rise) which is foundering below the base of the mantle transition zone. Additionally, we find a strong 520-km discontinuity beneath the southeastern United States which may indicate a hydrous transition zone due to the release of H2O from the Farallon slab. These results provide insight into the dynamics of flat slab subduction as well as the tectonic history of North America. [1] Livaccari, R. F., Burke, K., & Şengör, A. M. C. (1981). Was the Laramide orogeny related to subduction of an oceanic plateau? Nature, v. 289, p. 276-278, doi: 10.1038/289276a0

PLATEAU IRIS--DIAGNOSIS AND TREATMENT.

Science.gov (United States)

Stefan, Cornel; Iliescu, Daniela Adriana; Batras, Mehdi; Timaru, Cristina Mihaela; De Simone, Algerino

2015-01-01

The objective of our study was to review the current knowledge on the diagnosis and treatment options of plateau iris configuration and syndrome. Relevant publications on plateau iris that were published until 2014. Plateau iris syndrome is a form of primary angle closure glaucoma caused by a large or anteriorly positioned ciliary body that leads to mechanical obstruction of trabecular meshwork. This condition is most often found in younger patients. Plateau iris has been considered an abnormal anatomic variant of the iris that can be diagnosed on ultrasound biomicroscopy or optical coherence tomography of anterior segment. Patients with plateau iris syndrome can be recognized by the lack of response in angle opening after iridotomy. The treatment of choice in these cases is argon laser peripheral iridoplasty.

North-south patterning of millet agriculture on the Loess Plateau: Late Neolithic adaptations to water stress, NW China.

Science.gov (United States)

Sheng, P.; Shang, X.; Yang, L.; Jones, M.

2017-12-01

Abstract: Water availability and climatic condition profoundly affect agricultural system in different areas. The Loess Plateau, which lies on the marginal area of the East Asian monsoonal climatic zone, is one of the most ideal region to study the agricultural decision-making by ancient farm communities to adapt to different water stress level in same geographic region. Here we report new results of archaeobotanical research on the analysis of charred seeds from two late Neolithic sites on the northern Loess Plateau and review many contemporaneous archaeobotanical data recovered from the south and middle parts of the Loess Plateau. It is indicative of that common millet-based millet agriculture was developed in the arid northern Loess Plateau from the late Yangshao to Longshan periods (3000 1800 BC). Yet, there is a clear preference of foxtail millet farming with rice and wheat production as a supplement in the south and middle parts of the Loess Plateau during the same period. The north-south patterns of millet farming preferring by ancient farmers certainly promoted the social diversity and different evolutionary trajectories of human culture in both areas during the Mid-Late Holocene.

Subduction of a buoyant plateau at the Manila Trench: Tomographic evidence and geodynamic implications

Science.gov (United States)

Fan, Jianke; Zhao, Dapeng; Dong, Dongdong

2016-02-01

We determined P-wave tomographic images by inverting a large number of arrival-time data from 2749 local earthquakes and 1462 teleseismic events, which are used to depict the three-dimensional morphology of the subducted Eurasian Plate along the northern segment of the Manila Trench. Dramatic changes in the dip angle of the subducted Eurasian Plate are revealed from the north to the south, being consistent with the partial subduction of a buoyant plateau beneath the Luzon Arc. Slab tears may exist along the edges of the buoyant plateau within the subducted plate induced by the plateau subduction, and the subducted lithosphere may be absent at depths greater than 250 km at ˜19°N and ˜21°N. The subducted buoyant plateau is possibly oriented toward NW-SE, and the subducted plate at ˜21°N is slightly steeper than that at ˜19°N. These results may explain why the western and eastern volcanic chains in the Luzon Arc are separated by ˜50 km at ˜18°N, whereas they converge into a single volcanic chain northward, which may be related to the oblique subduction along the Manila Trench caused by the northwestern movement of the Philippine Sea Plate. A low-velocity zone is revealed at depths of 20-200 km beneath the Manila Accretionary Prism at ˜22°N, suggesting that the subduction along the Manila Trench may stop there and the collision develops northward. The Taiwan Orogeny may originate directly from the subduction of the buoyant plateau, because the initial time of the Taiwan Orogeny is coincident with that of the buoyant plateau subduction.

Composite analysis for low-level waste disposal in the 200 area plateau of the Hanford Site

International Nuclear Information System (INIS)

Kincaid, C.T.; Bergeron, M.P.; Cole, C.R.

1998-03-01

This report presents the first iteration of the Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site (Composite Analysis) prepared in response to the U.S. Department of Energy Implementation Plan for the Defense Nuclear Facility Safety Board Recommendation 94-2. The Composite Analysis is a companion document to published analyses of four active or planned low-level waste disposal actions: the solid waste burial grounds in the 200 West Area, the solid waste burial grounds in the 200 East Area, the Environmental Restoration Disposal Facility, and the disposal facilities for immobilized low-activity waste. A single Composite Analysis was prepared for the Hanford Site considering only sources on the 200 Area Plateau. The performance objectives prescribed in U.S. Department of Energy guidance for the Composite Analysis were 100 mrem in a year and examination of a lower dose (30 mrem in a year) to ensure the open-quotes as low as reasonably achievableclose quotes concept is followed. The 100 mrem in a year limit was the maximum allowable all-pathways dose for 1000 years following Hanford Site closure, which is assumed to occur in 2050. These performance objectives apply to an accessible environment defined as the area between a buffer zone surrounding an exclusive waste management area on the 200 Area Plateau, and the Columbia River. Estimating doses to hypothetical future members of the public for the Composite Analysis was a multistep process involving the estimation or simulation of inventories; waste release to the environment; migration through the vadose zone, groundwater, and atmospheric pathways; and exposure and dose. Doses were estimated for scenarios based on agriculture, residential, industrial, and recreational land use. The radionuclides included in the vadose zone and groundwater pathway analyses of future releases were carbon-14, chlorine-36, selenium-79, technetium-99, iodine-129, and uranium isotopes

Composite analysis for low-level waste disposal in the 200 area plateau of the Hanford Site

Energy Technology Data Exchange (ETDEWEB)

Kincaid, C.T.; Bergeron, M.P.; Cole, C.R. [and others

1998-03-01

This report presents the first iteration of the Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site (Composite Analysis) prepared in response to the U.S. Department of Energy Implementation Plan for the Defense Nuclear Facility Safety Board Recommendation 94-2. The Composite Analysis is a companion document to published analyses of four active or planned low-level waste disposal actions: the solid waste burial grounds in the 200 West Area, the solid waste burial grounds in the 200 East Area, the Environmental Restoration Disposal Facility, and the disposal facilities for immobilized low-activity waste. A single Composite Analysis was prepared for the Hanford Site considering only sources on the 200 Area Plateau. The performance objectives prescribed in U.S. Department of Energy guidance for the Composite Analysis were 100 mrem in a year and examination of a lower dose (30 mrem in a year) to ensure the {open_quotes}as low as reasonably achievable{close_quotes} concept is followed. The 100 mrem in a year limit was the maximum allowable all-pathways dose for 1000 years following Hanford Site closure, which is assumed to occur in 2050. These performance objectives apply to an accessible environment defined as the area between a buffer zone surrounding an exclusive waste management area on the 200 Area Plateau, and the Columbia River. Estimating doses to hypothetical future members of the public for the Composite Analysis was a multistep process involving the estimation or simulation of inventories; waste release to the environment; migration through the vadose zone, groundwater, and atmospheric pathways; and exposure and dose. Doses were estimated for scenarios based on agriculture, residential, industrial, and recreational land use. The radionuclides included in the vadose zone and groundwater pathway analyses of future releases were carbon-14, chlorine-36, selenium-79, technetium-99, iodine-129, and uranium isotopes.

Freshwater Biogeography and Limnological Evolution of the Tibetan Plateau - Insights from a Plateau-Wide Distributed Gastropod Taxon (Radix spp.)

Science.gov (United States)

von Oheimb, Parm Viktor; Albrecht, Christian; Riedel, Frank; Du, Lina; Yang, Junxing; Aldridge, David C.; Bößneck, Ulrich; Zhang, Hucai; Wilke, Thomas

2011-01-01

Background The Tibetan Plateau is not only the highest and largest plateau on earth; it is also home to numerous freshwater lakes potentially harbouring endemic faunal elements. As it remains largely unknown whether these lakes have continuously existed during the Last Glacial Maximum (LGM), questions arise as to whether taxa have been able to exist on the plateau since before the latest Pleistocene, from where and how often the plateau was colonized, and by which mechanisms organisms conquered remote high altitude lentic freshwater systems. In this study, species of the plateau-wide distributed freshwater gastropod genus Radix are used to answer these biogeographical questions. Methodology/Principal Findings Based on a broad spatial sampling of Radix spp. on the Tibetan Plateau, and phylogenetic analyses of mtDNA sequence data, three probably endemic and one widespread major Radix clade could be identified on the plateau. Two of the endemic clades show a remarkably high genetic diversity, indicating a relatively great phylogenetic age. Phylogeographical analyses of individuals belonging to the most widely distributed clade indicate that intra-plateau distribution cannot be explained by drainage-related dispersal alone. Conclusions/Significance Our study reveals that Radix spp. persisted throughout the LGM on the Tibetan Plateau. Therefore, we assume the continuous existence of suitable water bodies during that time. The extant Radix diversity on the plateau might have been caused by multiple colonization events combined with a relatively long intra-plateau evolution. At least one colonization event has a Palaearctic origin. In contrast to freshwater fishes, passive dispersal, probably by water birds, might be an important mechanism for conquering remote areas on the plateau. Patterns found in Radix spp. are shared with some terrestrial plateau taxa, indicating that Radix may be a suitable model taxon for inferring general patterns of biotic origin, dispersal and

Seismic Evidence for the North China Plate Underthrusting Beneath Northeastern Tibet and its Implications for Plateau Growth

Science.gov (United States)

Ye, Z.; Gao, R.; Li, Q.; Zhang, H.

2016-12-01

The effects of India-Asia collision and the subsequent interaction between the two continents on northeastern Tibet (NE Tibet), i.e., the tectonic transition zone between the Tibetan plateau and the North China craton (NCC) for example, remain uncertain due to inadequate geophysical data coverage in NE Tibet. Here in this research, based on new dataset collected from a dense linear array of 38 broadband seismograph stations, we applied seismic receiver functions (Sp and Ps converted waves) to imaging the lithospheric structure and shear wave splitting (XKS waves) to inspecting the anisotropy in the lithosphere and upper mantle beneath NE Tibet. The seismic array traverses NE Tibet to the westernmost NCC (Alxa block) in an SSW-NNE direction. The lithosphere-asthenosphere boundary (LAB) is clearly defined and appears as a south-dipping interface that runs continuously from the Alxa interior to the Qilian orogen on the S-wave receiver function images. Shear wave splitting measurements show significant lateral variations of seismic anisotropy across NE Tibet. Under joint constraints from both the lithospheric structure imaging and the regional anisotropic regime, combined with previous studies and through a thorough analysis/comparison/integration, we finally constructed a comprehensive lithospheric model of NE Tibet. The model tells that the NCC lithospheric mantle has been persistently underthrust beneath the Qilian orogen in response to on-going convergence/compression between the interior Tibetan plateau and the NCC. This process forms the syntectonic crustal thrust. The regional anisotropic regime can be well accommodated in our interpretation. The lithospheric model summarized here can be well accommodated in a scenario of northeastward migration of stepwise/multiple Aisan mantle lithosphere underthrusting beneath the Tibetan plateau. The multiple Aisan lithospheric blocks underthrust the plateau stepwise in small scale. Our results provide a new section from

Lateral Variations of the Mantle Transition Zone Structure beneath the Southeastern Tibetan Plateau Revealed by P-wave Receiver Functions

Science.gov (United States)

Bai, Y.; Ai, Y.; Jiang, M.; He, Y.; Chen, Q.

2017-12-01

The deep structure of the southeastern Tibetan plateau is of great scientific importance to a better understanding of the India-Eurasia collision as well as the evolution of the magnificent Tibetan plateau. In this study, we collected 566 permanent and temporary seismic stations deployed in SE Tibet, with a total of 77853 high quality P-wave receiver functions been extracted by maximum entropy deconvolution method. On the basis of the Common Conversion Point (CCP) stacking technique, we mapped the topography of the 410km and 660km discontinuities (hereinafter called the `410' and the `660'), and further investigated the lateral variation of the mantle transition zone (MTZ) thickness beneath this region. The background velocity model deduced from H-κ stacking results and a previous body-wave tomographic research was applied for the correction of the crustal and upper mantle heterogeneities beneath SE Tibet for CCP stacking. Our results reveal two significantly thickened MTZ anomalies aligned nearly in the south-north direction. The magnitude of both anomalies are 30km above the global average of 250km. The southern anomaly located beneath the Dianzhong sub-block and the Indo-China block is characterized by a slightly deeper `410' and a greater-than-normal `660', while the northern anomaly beneath western Sichuan has an uplifted `410' and a depressed `660'. Combining with previous studies in the adjacent region, we suggest that slab break-off may occurred during the eastward subduction of the Burma plate, with the lower part of the cold slab penetrated into the MTZ and stagnated at the bottom of the `660' which may cause the southern anomaly in our receiver function images. The origin of the Tengchong volcano is probably connected to the upwelling of the asthenospheric material caused by the slab break-off or to the ascending of the hot and wet material triggered by the dehydration of stagnant slab in the MTZ. The anomaly in the north, on the other hand, might be

Segmentation of Slow Slip Events in South Central Alaska Possibly Controlled by a Subducted Oceanic Plateau

Science.gov (United States)

Li, Haotian; Wei, Meng; Li, Duo; Liu, Yajing; Kim, YoungHee; Zhou, Shiyong

2018-01-01

Recent GPS observations show that slow slip events in south central Alaska are segmented along strike. Here we review several mechanisms that might contribute to this segmentation and focus on two: along-strike variation of slab geometry and effective normal stress. We then test them by running numerical simulations in the framework of rate-and-state friction with a nonplanar fault geometry. Results show that the segmentation is most likely related to the along-strike variation of the effective normal stress on the fault plane caused by the Yakutat Plateau. The Yakutat Plateau could affect the effective normal stress by either lowering the pore pressure in Upper Cook Inlet due to less fluids release or increasing the normal stress due to the extra buoyancy caused by the subducted Yakutat Plateau. We prefer the latter explanation because it is consistent with the relative amplitudes of the effective normal stress in Upper and Lower Cook Inlet and there is very little along-strike variation in Vp/Vs ratio in the fault zone from receiver function analysis. However, we cannot exclude the possibility that the difference in effective normal stress results from along-strike variation of pore pressure due to the uncertainties in the Vp/Vs estimates. Our work implies that a structural anomaly can have a long-lived effect on the subduction zone slip behavior and might be a driving factor on along-strike segmentation of slow slip events.

Seroprevalence of Capripoxvirus infection in sheep and goats among different agro-climatic zones of Odisha, India

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Abhishek Hota

2018-01-01

Full Text Available Aim: The study was undertaken to assess the prevalence of antibodies to Capripoxviruses among small ruminants of Odisha, India. Materials and Methods: A total of 500 random serum samples collected from 214 sheep and 286 goats across 10 agro-climatic zones of Odisha, were screened using whole virus antigen-based indirect ELISA for antibodies against Capripoxviruses. Results were analyzed by suitable statistical methods. Results: Screening of 500 serum samples showed seropositivity of 8.88% and 31.47% in sheep and goats, respectively, for Capripoxviruses. The prevalence rate according to agro-climatic zone ranged from 0% (North Eastern coastal plain zone to 48.57% (North central plateau zone for goat pox, and 0% (Western undulating zone and North central plateau to 22.22% (South Eastern ghat zone for sheep pox. The difference in prevalence rates among the various agro-climatic zones was statistically significant (p<0.05 for goats, but not for sheep. Antibody prevalence rates among various districts were recorded to be the highest in Jagatsinghpur (30% for sheep pox and Dhenkanal (80% for goat pox. Conclusion: The study revealed serological evidence of Capripoxvirus infection in sheep and goat populations in the study area, in the absence of vaccination. Systematic investigation, monitoring, and reporting of outbreaks are necessary to devise control strategies.

The relationship between the opening of South China Sea and the formation of the Tibetan Plateau (Invited)

Science.gov (United States)

Mo, X.

2010-12-01

The South China Sea is one of the largest marginal seas in western Pacific and underwent a complex history. Xu et al.(2004) suggested that the evolution of the South China Sea can be divided into two first order phases: Paleogene (—Early Miocene) rifting and Neogene post- rifting. An oceanic crust was formed during 32-17 Ma. Whether or not the opening of South China Sea were related to Indo-Eurasia collision and the formation of the Tibetan Plateau is one of challenging problem in Earth sciences. With an exception of the southwestern China, the Chinese continent has become an united continent in the Triassic by the Indosinian orogeny. However, the Qinghai-Tibet area in SW China was still an oceanic region, that is, the Neo-Tethys. During the period of 145-100 Ma, the Lhasa terrane collided with the Qiangtang terrane and added to the south margin of the Eurasian continent. On the other hand, the Indian plate subducted underneath the Eurasian continent since Jurassic- Cretaceous. Subsequently, collision between the two continents, India and Eurasia, were completed during 65-40 Ma, and went into a post-collisional stage, characterized by intra-continental movements, including intra-continental subduction, overthrust, strike-slip and so on. The Tibetan Plateau, the highest plateau in the world had been formed by multi-stage uplifts. Several huge strike-slip shear zone such as the Red River Fault and the Altyn were formed during that period. The >1000-km-long Oligocene—Miocene left-lateral Red River shear zone (RRSZ) and the Pliocene—active right-lateral Red River fault (RRF), stretching from SE Tibet to the South China Sea, has been cited as a lithospheric scale strike-slip fault. The age of RRSZ was recently determined no earlier than 31.9-24.2Ma and no later than 21.7 Ma (Searle et al., 2010). Many geologists believe that there possibly be close relationship between the opening of the South China Sea and Indo-Eurasia collision and the formation of the Tibetan

Potential productivity of the Miscanthus energy crop in the Loess Plateau of China under climate change

International Nuclear Information System (INIS)

Liu, Wei; Sang, Tao

2013-01-01

With a vast area of marginal land, the Loess Plateau of China is a promising region for large-scale production of second-generation energy crops. However, it remains unknown whether such production is sustainable in the long run, especially under climate change. Using a regional climate change model, PRECIS, we analyzed the impact of climate change on Miscanthus production in the Loess Plateau. Under three emission scenarios, A2, B2, and A1B, both the average yield and total area capable of supporting Miscanthus production would increase continuously in the future period (2011–2099). As a result, the total yield potential in the region would increase by about 20% in this future period from the baseline period (1961–1990). This was explained primarily by predicted increases in temperature and precipitation across the Loess Plateau, which improved the yield of the perennial C4 plants relying exclusively on rainfed production. The areas that are currently too dry or too cold to support Miscanthus production could be turned into energy crop fields, especially along the arid–semiarid transition zone. Thus the Loess Plateau would become increasingly desirable for growing second-generation energy crops in this century, which could in turn contribute to soil improvement and ecological restoration of the region. (letter)

Age of the Karakoram fault activation: 40Ar-39Ar geochronological study of Shyok suture zone in northern Ladakh, India

International Nuclear Information System (INIS)

Bhutani, Rajneesh; Pande, Kanchan; Desai, Nikhil

2003-01-01

Shyok volcanics, from the Shyok suture zone in northern Ladakh, ranging from basalts to andesites are analysed for 40 Ar- 30 Ar isotopic systematics by step heating experiment. All samples, collected along the Nubra river, in the vicinity of Karakoram fault zone, yielded disturbed age spectra, reflecting subsequent tectono-thermal events. However, consistency in the pattern of the age spectra, particularly at the low temperature steps, indicate a strong tectono-thermal event between ∼ 10 to ∼ 20 Ma ago. Mica-segregate from segregate from a sheared granite of Karakoram fault zone near village Murgi has yielded an excellent plateau age of 13.9 ± 0.1 Ma. This age of Karakoram fault activation explains the consistent but disturbed age spectra of Shyok volcanics within the vicinity of the fault zone. The Karakoram fault activation in Shyok suture zone is therefore synchronous with the extensional tectonic regime within the Tibetan plateau. (author)

Effects of temperature anisotropy on neoclassical transport in the plateau and banana-plateau regimes

International Nuclear Information System (INIS)

Taguchi, Masayoshi

1999-01-01

The neoclassical transport theory in a presence of temperature anisotropy is investigated in the low to the intermediate collision frequency regimes for a large aspect-ratio tokamak plasma. The standard procedure for an isotropic plasma in the plateau regime is extended to an anisotropic plasma, and the neoclassical transport coefficients in this regime are explicitly calculated. By interpolating the results in the plateau regime and the previously obtained ones in the banana regime, the expressions for the neoclassical transport coefficients which are continuously valid from the banana to the plateau regimes are presented. (author)

PLATEAU IRIS – DIAGNOSIS AND TREATMENT

Science.gov (United States)

Stefan, Cornel; Iliescu, Daniela Adriana; Batras, Mehdi; Timaru, Cristina Mihaela; De Simone, Algerino

2015-01-01

Objectives: The objective of our study was to review the current knowledge on the diagnosis and treatment options of plateau iris configuration and syndrome. Systematic review methodology: Relevant publications on plateau iris that were published until 2014. Conclusions: Plateau iris syndrome is a form of primary angle closure glaucoma caused by a large or anteriorly positioned ciliary body that leads to mechanical obstruction of trabecular meshwork. This condition is most often found in younger patients. Plateau iris has been considered an abnormal anatomic variant of the iris that can be diagnosed on ultrasound biomicroscopy or optical coherence tomography of anterior segment. Patients with plateau iris syndrome can be recognized by the lack of response in angle opening after iridotomy. The treatment of choice in these cases is argon laser peripheral iridoplasty PMID:27373109

Collision-induced post-plateau volcanism: Evidence from a seamount on Ontong Java Plateau

Science.gov (United States)

Hanyu, Takeshi; Tejada, Maria Luisa G.; Shimizu, Kenji; Ishizuka, Osamu; Fujii, Toshiyuki; Kimura, Jun-Ichi; Chang, Qing; Senda, Ryoko; Miyazaki, Takashi; Hirahara, Yuka; Vaglarov, Bogdan S.; Goto, Kosuke T.; Ishikawa, Akira

2017-12-01

Many seamounts on the Ontong Java Plateau (OJP) occur near the Stewart Arch, a topographic high that extends parallel to the North Solomon Trench along the southern margins of the plateau. Despite the thick sediment cover, several volcanic cones with strong acoustic reflection were discovered on the submarine flank of the Nuugurigia Seamount. From such volcanic cones, basalts were successfully sampled by dredging. Radiometric dating of basalts and ferromanganese encrustation indicate eruption age of 20-25 Ma, significantly younger than the 122 Ma main OJP plateau and post-plateau basalts. The age range coincides with the collision of the OJP with the Solomon Arc. The Nuugurigia basalts geochemically differ from any other rocks sampled on the OJP so far. They are alkali basalts with elevated Sr, low Zr and Hf, and Enriched Mantle-I (EMI)-like isotopic composition. Parental magmas of these alkali basalts may have formed by small-degree melting of peridotitic mantle impregnated with recycled pyroxenite material having enriched geochemical composition in the OJP's mantle root. We conclude that small-volume alkali basalts from the enriched mantle root migrated through faults or fractures caused by the collision along the Stewart Arch to form the seamount. Our results suggest that the collision of the OJP with the Solomon arc played an important role in the origin of similar post-plateau seamounts along the Stewart Arch.

Admixture, one-source colonization or long-term persistence of maritime pine in the Castilian Plateau? Insights from nuclear micro satellite markers

Energy Technology Data Exchange (ETDEWEB)

Lucas, A. I. de; Gonzalez Martinez, S. C.; Hidalgo, E.; Bravo, F.; Heuertz, M.

2009-07-01

Atlantic and Mediterranean populations of maritime pine are very different in quantitative and adaptive traits, even to be considered different subspecies. Different authors have suggested the existence of glacial refuge for this species both in Portugal and eastern Spain based on molecular markers and supported by pollen and fossil records. In addition, based on the existence of high levels of haplotypic variation in this region, the Castilian Plateau is suggested as a contact zone between Atlantic and Mediterranean gene pools of the species. This hypothesis is tested using Bayesian clustering methods and exclusion tests based on multi locus genotypes obtained by geno typing 13 populations with three highly polymorphic nuclear micro satellites. The results show that Castilian Plateau populations constitute a different gene pool by itself that can not be fully originated from the Mediterranean or the Atlantic gene pools, or from a mixture of both. Therefore, three different hypotheses have been considered as plausible causes to give rise to Castilian Plateau maritime pine populations: i) fast colonization of the region from one or more Mediterranean refugial areas, ii) existence of cryptic refugia for the species in the zone, and iii) introduction of exotic material by humans. (Author) 55 refs.

Reconstructing plateau icefields: Evaluating empirical and modelled approaches

Science.gov (United States)

Pearce, Danni; Rea, Brice; Barr, Iestyn

2013-04-01

Glacial landforms are widely utilised to reconstruct former glacier geometries with a common aim to estimate the Equilibrium Line Altitudes (ELAs) and from these, infer palaeoclimatic conditions. Such inferences may be studied on a regional scale and used to correlate climatic gradients across large distances (e.g., Europe). In Britain, the traditional approach uses geomorphological mapping with hand contouring to derive the palaeo-ice surface. Recently, ice surface modelling enables an equilibrium profile reconstruction tuned using the geomorphology. Both methods permit derivation of palaeo-climate but no study has compared the two methods for the same ice-mass. This is important because either approach may result in differences in glacier limits, ELAs and palaeo-climate. This research uses both methods to reconstruct a plateau icefield and quantifies the results from a cartographic and geometrical aspect. Detailed geomorphological mapping of the Tweedsmuir Hills in the Southern Uplands, Scotland (c. 320 km2) was conducted to examine the extent of Younger Dryas (YD; 12.9 -11.7 cal. ka BP) glaciation. Landform evidence indicates a plateau icefield configuration of two separate ice-masses during the YD covering an area c. 45 km2 and 25 km2. The interpreted age is supported by new radiocarbon dating of basal stratigraphies and Terrestrial Cosmogenic Nuclide Analysis (TCNA) of in situ boulders. Both techniques produce similar configurations however; the model results in a coarser resolution requiring further processing if a cartographic map is required. When landforms are absent or fragmentary (e.g., trimlines and lateral moraines), like in many accumulation zones on plateau icefields, the geomorphological approach increasingly relies on extrapolation between lines of evidence and on the individual's perception of how the ice-mass ought to look. In some locations this results in an underestimation of the ice surface compared to the modelled surface most likely due to

Present-day crustal deformation and strain transfer in northeastern Tibetan Plateau

Science.gov (United States)

Li, Yuhang; Liu, Mian; Wang, Qingliang; Cui, Duxin

2018-04-01

The three-dimensional present-day crustal deformation and strain partitioning in northeastern Tibetan Plateau are analyzed using available GPS and precise leveling data. We used the multi-scale wavelet method to analyze strain rates, and the elastic block model to estimate slip rates on the major faults and internal strain within each block. Our results show that shear strain is strongly localized along major strike-slip faults, as expected in the tectonic extrusion model. However, extrusion ends and transfers to crustal contraction near the eastern margin of the Tibetan Plateau. The strain transfer is abrupt along the Haiyuan Fault and diffusive along the East Kunlun Fault. Crustal contraction is spatially correlated with active uplifting. The present-day strain is concentrated along major fault zones; however, within many terranes bounded by these faults, intra-block strain is detectable. Terranes having high intra-block strain rates also show strong seismicity. On average the Ordos and Sichuan blocks show no intra-block strain, but localized strain on the southwestern corner of the Ordos block indicates tectonic encroachment.

The Evolution of Eastern Himalayan Syntaxis of Tibetan Plateau

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Zhang, S.; Wu, T.; Li, M.; Zhang, Y.; Hua, Y.; Zhang, B.

2017-12-01

Indian plate has been colliding with Eurasian plate since 50Ma years ago, resulting in the Tethys extinction, crust shortening and Tibetan plateau uplift. But it is still a debate how the Tibetan Plateau material escaped. This study tries to invert the distributions of dispersion phase velocity and anisotropy in Eastern Himalayan Syntaxis (EHS) based on the seismic data. We focused on the seven sub-blocks around EHS region. Sub-block "EHS" represents EHS corner with high velocity anomalies, significantly compressed in the axle and strike directions. Sub-blocks "LSD", "QTB" and "SP-GZB" are located at its northern areas with compressions also, and connected with low-velocity anomalies in both crustal and upper mantle rocks. Sub-block "ICB" is located at its southern area with low velocity anomaly, and connected with Tengchong volcano. Sub-blocks "SYDB" and "YZB" are located at its eastern areas with high velocity anomalies in both crustal and upper mantle rocks. Our results demonstrated that significant azimuthal anisotropy of crust (t£30s) and upper mantle (30s£t£60s). Crustal anisotropy indicates the orogenic belt matched well with the direction of fast propagation, and upper mantle anisotropy represents the lattic-preferred orientation (LPO) of mantle minerals (e.g. olivine and basalt), indicating the features of subducting Indian plate. Besides, Red River fault is a dextral strike fault, controlling the crustal and mantle migration. There is a narrow zone to be the channel flow of Tibetan crustal materials escaping toward Yunnan area. The evolution of EHS seems constrained by gravity isostatic mechanism. Keywords: Tibetan Plateau; Eastern Himalayan Syntaxis; Red River fault; crustal flow; surface wave; anisotropy

Intrinsic vulnerability assessment of Sette Comuni Plateau aquifer (Veneto Region, Italy).

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Cucchi, Franco; Franceschini, Giuliana; Zini, Luca; Aurighi, Marina

2008-09-01

Maps illustrating the different degrees of vulnerability within a given area are integral to environmental protection and management policies. The assessment of the intrinsic vulnerability of karst areas is difficult since the type and stage of karst development and the related underground discharge behavior are difficult to determine and quantify. Geographic Information Systems techniques are applied to the evaluation of the vulnerability of an aquifer in the alpine karst area of the Sette Comuni Plateau, in the Veneto Region of northern Italy. The water resources of the studied aquifer are of particular importance to the local communities. This aquifer must therefore be protected from both inappropriate use as well as possible pollution. The SINTACS and SINTACS P(RO) K(ARST) vulnerability assessment methods have been utilized here to create the vulnerability map. SINTACS P(RO) K(ARST) is an adaptation of the parametric managerial model (SINTACS) to karst hydrostructures. The vulnerability map reveals vast zones (81% of the analyzed areas) with a high degree of vulnerability. The presence of well-developed karst structures in these highly vulnerable areas facilitate water percolation, thereby enhancing the groundwater vulnerability risk. Only 1.5 of the studied aquifer have extremely high-vulnerability levels, however these areas include all of the major springs utilized for human consumption. This vulnerability map of the Sette Comuni Plateau aquifer is an indispensable tool for both the effective management of water resources and as support to environmental planning in the Sette Comuni Plateau area.

[Accumulation, distribution and pollution assessment of heavy metals in surface sediment of Caohai plateau wetland, Guizhou province].

Science.gov (United States)

Zhang, Qing-Hai; Lin, Chang-Hu; Tan, Hong; Lin, Shao-Xia; Yang, Hong-Bo

2013-03-01

The objective of this paper is to investigate the concentrations and distribution characteristics of heavy metals in surface sediments of different areas in the Caohai plateau wetland. 16 samples of surface sediments were collected and 7 heavy metals were analyzed. Heavy metal pollution in surface sediments of different areas in the Caohai plateau wetland was estimated by the Tomlinson Pollution Load Index (PLI) method. The analyzed results indicated that the average contents of Cd, Hg, As, Pb, Cr, Cu, Zn were 0.985, 0.345, 15.8, 38.9, 38.6, 22.8 and 384 mg x kg(-1), respectively. The heavy metal distributions varied with regional environment changes, the order of average contents of Cd and Hg in different regions was E (the eastern region) > S (the southern region) > N (the northern region), the order of the average content of Pb was N > E > S, and that of Zn was S > E > N. The results also suggested a medium heavy metal pollution level in the surface sediment of the Caohai plateau wetland with the PLI(zone) reaching 1.17. The order of pollution level in surface sediments of different regions was E > S > N. The results showed medium pollution levels in E and Hg which reached the extreme intensity pollution level were also the major polluted elements in surface sediments of the Caohai plateau wetland. And also, results showed medium pollution levels of Cd and Pb in surface sediments of Caohai plateau wetland. Cluster analysis results showed similar pollution sources of Cd, Zn, Pb and Hg, which should be attached great importance in terms of the prevention of the Caohai plateau wetland.

Developing the remote sensing-based water environmental model for monitoring alpine river water environment over Plateau cold zone

Science.gov (United States)

You, Y.; Wang, S.; Yang, Q.; Shen, M.; Chen, G.

2017-12-01

Alpine river water environment on the Plateau (such as Tibetan Plateau, China) is a key indicator for water security and environmental security in China. Due to the complex terrain and various surface eco-environment, it is a very difficult to monitor the water environment over the complex land surface of the plateau. The increasing availability of remote sensing techniques with appropriate spatiotemporal resolutions, broad coverage and low costs allows for effective monitoring river water environment on the Plateau, particularly in remote and inaccessible areas where are lack of in situ observations. In this study, we propose a remote sense-based monitoring model by using multi-platform remote sensing data for monitoring alpine river environment. In this study some parameterization methodologies based on satellite remote sensing data and field observations have been proposed for monitoring the water environmental parameters (including chlorophyll-a concentration (Chl-a), water turbidity (WT) or water clarity (SD), total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC)) over the china's southwest highland rivers, such as the Brahmaputra. First, because most sensors do not collect multiple observations of a target in a single pass, data from multiple orbits or acquisition times may be used, and varying atmospheric and irradiance effects must be reconciled. So based on various types of satellite data, at first we developed the techniques of multi-sensor data correction, atmospheric correction. Second, we also built the inversion spectral database derived from long-term remote sensing data and field sampling data. Then we have studied and developed a high-precision inversion model over the southwest highland river backed by inversion spectral database through using the techniques of multi-sensor remote sensing information optimization and collaboration. Third, take the middle reaches of the Brahmaputra river as the study area, we validated the key

Comparison of trapezius squeeze test and jaw thrust as clinical indicators for laryngeal mask airway insertion in spontaneously breathing children

Science.gov (United States)

Dinesh Kumar, K. K.; Bhardwaj, Neerja; Yaddanapudi, Sandhya

2017-01-01

Background and Aims: It is not known whether trapezius squeeze test (TPZ) is a better clinical test than jaw thrust (JT) to assess laryngeal mask airway (LMA) insertion conditions in children under sevoflurane anesthesia. Material and Methods: After the Institutional Ethics Committee approval and written informed parental consent, 124 American Society of Anesthesiologists I and II children of 2–8 years of age undergoing minor surgical procedures were randomized into TPZ and JT groups. The children were induced with 8% sevoflurane in oxygen at a fresh gas flow of 4 L/min. TPZ or JT was performed after 1 min of start of sevoflurane and then every 20 s till the test was negative, when end-tidal (ET) sevoflurane concentration was noted. Classic LMA of requisite size was inserted by a blinded anesthetist and conditions at the insertion of LMA, insertion time, and the number of attempts of LMA insertion were recorded. Results: The mean LMA insertion time was significantly longer (P < 0.001) for TPZ (145 ± 28.7 sec) compared to JT group (111.8 ± 31.0 sec). ET sevoflurane concentration at the time of LMA insertion was comparable in the two groups. LMA insertion conditions were similar in the two groups. There was no difference between the two groups regarding total number of attempts of LMA insertion. Heart rate (HR) decreased in both groups after LMA insertion (P < 0.001) but TPZ group had significantly lower HR compared with the JT group up to 5 min after LMA insertion (P = 0.03). Conclusion: Both JT and TPZ are equivalent clinical indicators in predicting the optimal conditions of LMA insertion in spontaneously breathing children; however, it takes a longer time to achieve a negative TPZ squeeze test. PMID:28413275

NON-GENETIC EFFECT ON BODY WEIGHT AND BODY MEASUREMENT OF INDIGENOUS GOATS AT DIFFERENT STAGES OF GROWTH IN NORTH CENTRAL PLATEAU CLIMATIC ZONE OF ODISHA, INDIA

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S. Ray

2015-12-01

Full Text Available The effect of season of birth, type of birth, sex and parity on body weight of indigenous goats under field condition in north central plateau agro-climatic zone of Odisha was studied. Data from 622 kids revealed that the overall body weights were 1.02± 0.01, 4.27± 0.03, 7.29± 0.05, 9.42± 0.08 and 12.09± 0.12 kg at birth, 3 month, 6 month, 9 month and 12 month of age, respectively. Multiple births in the population were 72.3%. Significant difference was observed between male and female goats with respect to body weight in all stages of growth.Multiple births had significant effect on body weights of kids till 6 month of age. Season of birth had significant effect on body weight of kids only at birth and 3 month of age but parity did not show any significant effect on body weight at any studied stages.

PLATEAUING COSMIC RAY DETECTORS TO ACHIEVE OPTIMUM OPERATING VOLTAGE

Energy Technology Data Exchange (ETDEWEB)

Knoff, E.N.; Peterson, R.S.

2008-01-01

Through QuarkNet, students across the country have access to cosmic ray detectors in their high school classrooms. These detectors operate using a scintillator material and a photomultiplier tube (PMT). A data acquisition (DAQ) board counts cosmic ray hits from the counters. Through an online e-Lab, students can analyze and share their data. In order to collect viable data, the PMTs should operate at their plateau voltages. In these plateau ranges, the number of counts per minute remains relatively constant with small changes in PMT voltage. We sought to plateau the counters in the test array and to clarify the plateauing procedure itself. In order to most effectively plateau the counters, the counters should be stacked and programmed to record the number of coincident hits as well as their singles rates. We also changed the threshold value that a signal must exceed in order to record a hit and replateaued the counters. For counter 1, counter 2, and counter 3, we found plateau voltages around 1V. The singles rate plateau was very small, while the coincidence plateau was very long. The plateau voltages corresponded to a singles rate of 700–850 counts per minute. We found very little effect of changing the threshold voltages. Our chosen plateau voltages produced good performance studies on the e-Lab. Keeping in mind the nature of the experiments conducted by the high school students, we recommend a streamlined plateauing process. Because changing the threshold did not drastically affect the plateau voltage or the performance study, students should choose a threshold value, construct plateau graphs, and analyze their data using a performance study. Even if the counters operate slightly off their plateau voltage, they should deliver good performance studies and return reliable results.

Deep Vadose Zone Treatability Test of Soil Desiccation for the Hanford Central Plateau: Final Report

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chronister, Glen B. [CH2M Hill Plateau Remediation Co., Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tartakovsky, Guzel D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Vicky L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rockhold, Mark L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greenwood, William J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Peterson, John E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hubbard, Susan S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ward, Anderson L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2018-02-20

Some of the inorganic and radionuclide contaminants in the deep vadose zone at the Hanford Site are at depths where direct exposure pathways are not of concern, but may need to be remediated to protect groundwater. The Department of Energy developed a treatability test program for technologies to address Tc-99 and uranium in the deep vadose zone. These contaminants are mobile in the subsurface environment, have been detected at high concentrations deep in the vadose zone, and at some locations have reached groundwater. The treatability test of desiccation described herein was conducted as an element of the deep vadose zone treatability test program. Desiccation was shown to be a potentially effective vadose zone remediation technology to protect groundwater when used in conjunction with a surface infiltration barrier.

Vertebrate Fossils Imply Paleo-elevations of the Tibetan Plateau

Science.gov (United States)

Deng, T.; Wang, X.; Li, Q.; Wu, F.; Wang, S.; Hou, S.

2017-12-01

The uplift of the Tibetan Plateau remains unclear, and its paleo-elevation reconstructions are crucial to interpret the geodynamic evolution and to understand the climatic changes in Asia. Uplift histories of the Tibetan Plateau based on different proxies differ considerably, and two viewpoints are pointedly opposing on the paleo-elevation estimations of the Tibetan Plateau. One viewpoint is that the Tibetan Plateau did not strongly uplift to reach its modern elevation until the Late Miocene, but another one, mainly based on stable isotopes, argues that the Tibetan Plateau formed early during the Indo-Asian collision and reached its modern elevation in the Paleogene or by the Middle Miocene. In 1839, Hugh Falconer firstly reported some rhinocerotid fossils collected from the Zanda Basin in Tibet, China and indicated that the Himalayas have uplifted by more than 2,000 m since several million years ago. In recent years, the vertebrate fossils discovered from the Tibetan Plateau and its surrounding areas implied a high plateau since the late Early Miocene. During the Oligocene, giant rhinos lived in northwestern China to the north of the Tibetan Plateau, while they were also distributed in the Indo-Pakistan subcontinent to the south of this plateau, which indicates that the elevation of the Tibetan Plateau was not too high to prevent exchanges of large mammals; giant rhinos, the rhinocerotid Aprotodon, and chalicotheres still dispersed north and south of "Tibetan Plateau". A tropical-subtropical lowland fish fauna was also present in the central part of this plateau during the Late Oligocene, in which Eoanabas thibetana was inferred to be closely related to extant climbing perches from South Asia and Sub-Saharan Africa. In contrast, during the Middle Miocene, the shovel-tusked elephant Platybelodon was found from many localities north of the Tibetan Plateau, while its trace was absent in the Siwaliks of the subcontinent, which implies that the Tibetan Plateau had

Prehistoric human settling on the Tibetan Plateau

Science.gov (United States)

Chen, F.; Zhang, D.; Dong, G.; Xia, H.

2017-12-01

When and where did human first settle down on the Tibetan Plateau is under hot debate among archaeologist, anthropologists, geneticist and paleo-geographers. Based on systematic archaeological, chronological and archaeo-botanical studies of 53 sites in Northeastern Tibetan Plateau, we propose that agriculture facilitated human permanent settlement on the Tibetan Plateau initially since 5200 years ago below 2500 masl and since 3600 years ago up to around 4000 masl, possibly assisted by domesticated animals (Chen et al. 2015). By redating the age of hand- and footprints in Chusang site in Tibet, Meyer et al. (2017) argue that hunter-gatherers permanently occupied central Tibetan Plateau in early Holocene (before 7.4 ka) without the help of agriculture. Except for the possible problem of dating, however, the limited hand- and footprints could only indicate the presence of prehistoric hunter-gatherers on the remote central Tibetan Plateau in the early Holocene, unable to support the permanent inhabitation assertion (Zhang et al., 2017). To better understand how human spread to, settle on and adapt to the Tibetan Plateau, we are closely working together with anthropologists, archaeologists and geneticists to do system Paleolithic surveys, full excavations, and genetic analysis of ancient and modern human, animals and plants. Our preliminary study show that human migrated to the Tibetan Plateau from the last Deglacial period to late Holocene mainly from North China via Yellow River valley and its tributary valleys in the Northeastern Tibetan Plateau (NETP). This migration is constituted of four stages (Upper Paleolithic, Epi-Paleolithic, Neolithic and Bronze Age) with different adaptation strategies, including microlithic technology, millet and barley farming, and sheep herding and so on (Zhang et al., 2016). In addition, our new finds in Tibet indicate that there are probably more migration routes from southeast and southwest Tibetan Plateau in the late Pleistocene or

[Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.

Science.gov (United States)

Zhu, Duo Ju; Wen, Zhong Ming; Zhang, Jing; Tao, Yu; Zeng, Hong Wen; Tang, Yang

2018-02-01

To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FR ic , FE ve , FD iv , FD is , Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.

CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY

Energy Technology Data Exchange (ETDEWEB)

BERGMAN, T. B.; STEFANSKI, L. D.; SEELEY, P. N.; ZINSLI, L. C.; CUSACK, L. J.

2012-09-19

THE CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY WAS CONDUCTED TO DEVELOP AN OPTIMAL SEQUENCE OF REMEDIATION ACTIVITIES IMPLEMENTING THE CERCLA DECISION ON THE CENTRAL PLATEAU. THE STUDY DEFINES A SEQUENCE OF ACTIVITIES THAT RESULT IN AN EFFECTIVE USE OF RESOURCES FROM A STRATEGIC PERSPECTIVE WHEN CONSIDERING EQUIPMENT PROCUREMENT AND STAGING, WORKFORCE MOBILIZATION/DEMOBILIZATION, WORKFORCE LEVELING, WORKFORCE SKILL-MIX, AND OTHER REMEDIATION/DISPOSITION PROJECT EXECUTION PARAMETERS.

Functional-trait ecology of the plateau pika Ochotona curzoniae (Hodgson, 1858) in the Qinghai-Tibetan Plateau ecosystem.

Science.gov (United States)

Smith, Andrew T; Badingqiuying; Wilson, Maxwell C; Hogan, Brigitte W

2018-01-09

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, thus its relative importance to conservation planning. The functional trait ecology of the plateau pika Ochotona curzoniae (Hodgson, 1858) is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re-introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas. This article is protected by copyright. All rights reserved.

Heat flow in the north-central Colorado Plateau

International Nuclear Information System (INIS)

Bodell, J.M.; Chapman, D.S.

1982-01-01

We report new heat flow measurements at 25 evenly distributed sites in the north-central Colorado Plateau. Heat flow values computed for these new sites and one previously published site range from 43 to 116 mW m -2 but fall into the following district subsets related to physiographic and tectonic elements within the Plateau: (1) heat flow of 51 mW m -2 (12 sites; s.d. 6) in the San Rafael Swell and Green River Desert which constitute the core of the Colorado Plateau at this latitude, (2) heat flows of 69 mW m -2 (5 sites; s.d. 10) in successive parallel north-south bands approaching the Wasatch Plateau to the west but still 80 km east of the Basin and Range physiographic boundary, (3) heat flow of 64 mW m -2 (5 sites; s.d. 2) along the Salt Anticline trend which strikes northwest in the region of Moab, Utah. Heat flow results for the entire Colorado Plateau have been reexamined in view of our new results, and the overall pattern supports the concept of a low heat flow 'thermal interior' for the plateau surrounded by a periphery some 100 km wide having substantially higher heat flow. Average heat flow in the thermal interior is about 60 mW m -2 compared to 80--90 mW m -2 in the periphery. This regional heat flow pattern supports a model of tertiary lithospheric thinning under the Colorado Plateau whereby the plateau is still in transient thermal response and a 15--20 m.y. lag between uplift and corresponding surface heat flow anomaly is to be expected. The position of the heat flow transition between our interior and peripheral regions in the northwest plateau is roughly consistent with lateral warming and weakening of the Colorado Plateau lithosphere initiated at the Basin and Range boundary some 20 m.y. ago

Reinterpretation of the tectonics and formation of the Pernambuco Plateau Basin, NE Brazil.

Science.gov (United States)

Hoggett, Murray; Jones, Stephen M.; Dunkley Jones, Tom; Reston, Timothy; Barbosa, Antonio; Biondo, Vanessa; Mort, Haydon P.

2017-04-01

The continental margin from Alagoas to Natal represents arguably the most frontier region for exploration on the Brazillian margin. High quality seismic data was not collected in the region for many decades as it was believed that only a few kilometers of sediment existed, and thus there was no exploration potential. Here we present the results of work done as part of an IODP virtual site survey. The work has resulted in a total reinterpretation of the basin structure and tectonics, including finding sediment filled half grabens holding up to 8km thick stratigraphic sections. The two deepest grabens likely represent rift jumps during breakup, which may imply different age sediments in the different grabens. The basin is also found to contain a sizable salt accumulation, previously uninterpreted due to hard overlying carbonates hampering seismic imaging. This salt can be seen to have been highly mobile in the past, and has developed into kilometer scale diapirs flanked by typical rollover anticlines. For the first time we show the basin has all the elements needed for a working petroleum system, with the exception a source rock - which cannot be speculated on further as the basin is undrilled. However source rock sequences are present in the Alagoas basin to the south, and recent released seep data show evidence for both biogeneic and thermogenic seeps over the plateau basin, which could also signal source rock presence. We present seismic and potential fields data, including forward potential fields models and seismically derived crustal stretching and thinning estimates, to show that the half grabens terminate abruptly at the latitude of the Pernambuco Shear Zone, a major crustal scale Precambrian shear zone. Onshore boreholes, well away from the deep seismically imaged half grabens offshore, find crystalline basement to drop away rapidly across the shearzone, revealing a third graben to terminate at the shear zone. We interpret this as that the preexisting

An avifaunal case study of a plateau from Goa, India: an eye opener for conservation of plateau ecosystems

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Minal Desai

2012-03-01

Full Text Available The lateritic plateaux typical of the midlands between the Western Ghats and the coastal plains of the Arabian Sea are known to be a unique ecosystem with a sizeable endemic flora. However, there is a total lack of studies on the faunal diversity of these plateaux, which are currently experiencing enormous anthropogenic pressures. We conducted a year-long study on the avifauna of the Taleigao Plateau, Goa. The Taleigao Plateau harbours 114 species of birds, accounting for 37% of the avifaunal diversity of the state. The resident bird population did not vary significantly through the seasons. Among the migrant birds, Rosy Starling Sturnus roseus was particularly partial to the plateau. Besides, five species of larks, grassland specialists were also recorded on the plateau. However, the absence of forest birds like the Malabar Pied Hornbill and the Indian Grey Hornbill (recorded earlier and the predominance of habitat generalists like the House Crow and the Jungle Myna seemed to be the offshoot of heavy anthropogenic pressures on the plateau. It is recommended that at least some plateaux in the belt deserve to be protected from the impact of unsustainable developmental process

A possible cause of the Miocene uplift and volcanism in the central Anatolian plateau

Science.gov (United States)

Bartol, J.; Govers, R. M.; Wortel, M. J.

2010-12-01

During the middle and late Miocene (13-5Ma) several seemingly unrelated events occurred in central Anatolia, Turkey; (1) a new epoch of widespread volcanic activity with a mantle signature, (2) sudden uplift and disruption of a Oligocene-lower Miocene palaeo drainage system in the Western Taurus (southwest Turkey) and (3) a regional regression across southern Turkey (Antalya, Adana, Mut) coeval with volcanic activity. These observations suggest an uplift (>1000 meters) of the central Anatolian plateau by a mechanism which also triggered widespread volcanic activity. In eastern Anatolia, similar events are attributed to delamination of the lithospheric mantle [e.g. Keskin et al., 2003]. Results from tomography [W.Spakman, pers. com]) suggest that the (deeper) Bitlis slab was laterally continuous below the eastern and central Anatolian plateau. We therefore propose that the scenario developed for eastern Anatolian plateau also applies to the central Anatolian plateau. In this scenario, delamination started along the Izmir-Ankara-Erzincan suture zone and was possibly induced by remnants of a northern Neotethys slab or continental collision between Arabia and Eurasia. As the lithospheric mantle separated from the crust it sank into the asthenosphere and was replaced by hot mantle material. If true, delamination is expected to have had a thermal and isostatic imprint. Using a three-dimensional thermal-flexural model and taking changes of the effective elastic thickness due to thermal perturbation into account, we aim to quantify the possible imprints in the geological record of the central and eastern Anatolian plateau. Our model results show that delamination of the lithospheric mantle can explain the present day elevation (1500 m) of the central Anatolian plateau. For the eastern Anatolian plateau, however, delamination of the lithospheric mantle alone can only explain half (1000 m) of the present day elevation. Thickening of the eastern Anatolia crust by 1-5 km (β=1

A new classification of large-scale climate regimes around the Tibetan Plateau based on seasonal circulation patterns

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Xin-Gang Dai

2017-03-01

Full Text Available This study aims to develop a large-scale climate classification for investigating the characteristics of the climate regimes around the Tibetan Plateau based on seasonal precipitation, moisture transport and moisture divergence using in situ observations and ERA40 reanalysis data. The results indicate that the climate can be attributed to four regimes around the Plateau. They situate in East Asia, South Asia, Central Asia and the semi-arid zone in northern Central Asia throughout the dryland of northwestern China, in addition to the Köppen climate classification. There are different collocations of seasonal temperature and precipitation: 1 in phase for the East and South Asia monsoon regimes, 2 anti-phase for the Central Asia regime, 3 out-of-phase for the westerly regime. The seasonal precipitation concentrations are coupled with moisture divergence, i.e., moisture convergence coincides with the Asian monsoon zone and divergence appears over the Mediterranean-like arid climate region and westerly controlled area in the warm season, while it reverses course in the cold season. In addition, moisture divergence is associated with meridional moisture transport. The northward/southward moisture transport corresponds to moisture convergence/divergence, indicating that the wet and dry seasons are, to a great extent, dominated by meridional moisture transport in these regions. The climate mean southward transport results in the dry-cold season of the Asian monsoon zone and the dry-warm season, leading to desertification or land degradation in Central Asia and the westerly regime zone. The mean-wind moisture transport (MMT is the major contributor to total moisture transport, while persistent northward transient eddy moisture transport (TEMT plays a key role in dry season precipitation, especially in the Asian monsoon zone. The persistent TEMT divergence is an additional mechanism of the out-of-phase collocation in the westerly regime zone. In addition

Plateau subduction, intraslab seismicity, and the Denali (Alaska) volcanic gap

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Chuang, Lindsay Yuling; Bostock, Michael; Wech, Aaron; Plourde, Alexandre

2018-01-01

Tectonic tremors in Alaska (USA) are associated with subduction of the Yakutat plateau, but their origins are unclear due to lack of depth constraints. We have processed tremor recordings to extract low-frequency earthquakes (LFEs), and generated a set of six LFE waveform templates via iterative network matched filtering and stacking. The timing of impulsive P (compressional) wave and S (shear) wave arrivals on template waveforms places LFEs at 40–58 km depth, near the upper envelope of intraslab seismicity and immediately updip of increased levels of intraslab seismicity. S waves at near-epicentral distances display polarities consistent with shear slip on the plate boundary. We compare characteristics of LFEs, seismicity, and tectonic structures in central Alaska with those in warm subduction zones, and propose a new model for the region’s unusual intraslab seismicity and the enigmatic Denali volcanic gap (i.e., an area of no volcanism where expected). We argue that fluids in the Yakutat plate are confined to its upper crust, and that shallow subduction leads to hydromechanical conditions at the slab interface in central Alaska akin to those in warm subduction zones where similar LFEs and tremor occur. These conditions lead to fluid expulsion at shallow depths, explaining strike-parallel alignment of tremor occurrence with the Denali volcanic gap. Moreover, the lack of double seismic zone and restriction of deep intraslab seismicity to a persistent low-velocity zone are simple consequences of anhydrous conditions prevailing in the lower crust and upper mantle of the Yakutat plate.

The impact of afforestation on soil organic carbon sequestration on the Qinghai Plateau, China.

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Sheng-wei Shi

Full Text Available Afforestation, the conversion of non-forested land into forest, is widespread in China. However, the dynamics of soil organic carbon (SOC after afforestation are not well understood, especially in plateau climate zones. For a total of 48 shrub- and/or tree-dominated afforestation sites on the Qinghai Plateau, Northwestern China, post-afforestation changes in SOC, total nitrogen (TN, the carbon-to-nitrogen ratio (C/N and soil bulk density (BD were investigated to a soil depth of 60 cm using the paired-plots method. SOC and TN accumulated at rates of 138.2 g C m(-2 yr(-1 and 4.6 g N m(-2 yr(-1, respectively, in shrub-dominated afforestation sites and at rates of 113.3 g C m(-2 yr(-1 and 6.7 g N m(-2 yr(-1, respectively, in tree-dominated afforestation sites. Soil BD was slightly reduced in all layers in the shrub-dominated afforestation plots, and significantly reduced in soil layers from 0-40cm in the tree-dominated afforestation plots. The C/N ratio was higher in afforested sites relative to the reference sites. SOC accumulation was closely related to TN accumulation following afforestation, and the inclusion of N-fixing species in tree-dominated afforestation sites additionally increased the soil accumulation capacity for SOC (p < 0.05. Multiple regression models including the age of an afforestation plot and total number of plant species explained 75% of the variation in relative SOC content change at depth of 0-20 cm, in tree-dominated afforestation sites. We conclude that afforestation on the Qinghai Plateau is associated with great capability of SOC and TN sequestration. This study improves our understanding of the mechanisms underlying SOC and TN accumulation in a plateau climate, and provides evidence on the C sequestration potentials associated with forestry projects in China.

Colorado Plateau magmatism and uplift by warming of heterogeneous lithosphere.

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Roy, Mousumi; Jordan, Thomas H; Pederson, Joel

2009-06-18

The forces that drove rock uplift of the low-relief, high-elevation, tectonically stable Colorado Plateau are the subject of long-standing debate. While the adjacent Basin and Range province and Rio Grande rift province underwent Cenozoic shortening followed by extension, the plateau experienced approximately 2 km of rock uplift without significant internal deformation. Here we propose that warming of the thicker, more iron-depleted Colorado Plateau lithosphere over 35-40 Myr following mid-Cenozoic removal of the Farallon plate from beneath North America is the primary mechanism driving rock uplift. In our model, conductive re-equilibration not only explains the rock uplift of the plateau, but also provides a robust geodynamic interpretation of observed contrasts between the Colorado Plateau margins and the plateau interior. In particular, the model matches the encroachment of Cenozoic magmatism from the margins towards the plateau interior at rates of 3-6 km Myr(-1) and is consistent with lower seismic velocities and more negative Bouguer gravity at the margins than in the plateau interior. We suggest that warming of heterogeneous lithosphere is a powerful mechanism for driving epeirogenic rock uplift of the Colorado Plateau and may be of general importance in plate-interior settings.

Computed tomography of tibial plateau fractures

International Nuclear Information System (INIS)

Rafii, M.; Firooznia, H.; Golimbu, C.; Bonamo, J.

1984-01-01

Twenty patients with tibial plateau fractures were studied by conventional tomography and computed tomography (CT) in order to determine the role and feasibility of CT in management of such patients. CT resulted in less discomfort to the patient and provided optimal visualization of the plateau defect and the split fragments. It proved more accurate than conventional tomography in assessing depressed and split fractures when they involved the anterior or posterior border of the plateau and in demonstrating the extent of fracture comminution. Split fragments with an oblique plane of fracture also were seen better by CT. The degree of fracture depression and separation as measured by the computerized technique was often more accurate than measurements obtained from conventional tomograms

Resource use and food self-sufficiency at farm scale within two agro-ecological zones of Rwanda

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Bucagu, C.; Vanlauwe, B.; Wijk, van M.T.; Giller, K.E.

2014-01-01

Resource use and management are major determinants of the food self-sufficiency of smallholder farmers in sub-Saharan Africa. A study was conducted in Rwanda in two contrasting agro-ecological zones (Central plateau and Buberuka) to characterise farms, quantify their resource flows, and evaluate the

Tectonic setting of Cretaceous basins on the NE Tibetan Plateau: Insights from the Jungong basin

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Craddock, W.H.; Kirby, E.; Dewen, Z.; Jianhui, L.

2012-01-01

Quantifying the Cenozoic growth of high topography in the Indo-Asian collision zone remains challenging, due in part to significant shortening that occurred within Eurasia before collision. A growing body of evidence suggests that regions far removed from the suture zone experienced deformation before and during the early phases of Himalayan orogenesis. In the present-day north-eastern Tibetan Plateau, widespread deposits of Cretaceous sediment attest to significant basin formation; however, the tectonic setting of these basins remains enigmatic. We present a study of a regionally extensive network of sedimentary basins that are spatially associated with a system of SE-vergent thrust faults and are now exposed in the high ranges of the north-eastern corner of the Tibetan Plateau. We focus on a particularly well-exposed basin, located ~20km north of the Kunlun fault in the Anyemaqen Shan. The basin is filled by ~900m of alluvial sediments that become finer-grained away from the basin-bounding fault. Additionally, beds in the proximal footwall of the basin-bounding fault exhibit progressive, up-section shallowing and several intraformational unconformities which can be traced into correlative conformities in the distal part of the basin. The observations show sediment accumulated in the basin during fault motion. Regional constraints on the timing of sediment deposition are provided by both fossil assemblages from the Early Cretaceous, and by K-Ar dating of volcanic rocks that floor and cross-cut sedimentary fill. We argue that during the Cretaceous, the interior NE Tibetan Plateau experienced NW-SE contractional deformation similar to that documented throughout the Qinling-Dabie orogen to the east. The Songpan-Ganzi terrane apparently marked the southern limit of this deformation, such that it may have been a relatively rigid block in the Tibetan lithosphere, separating regions experiencing deformation north of the convergent Tethyan margin from regions deforming

Quantifying the Plutonic to Volcanic Relationship Along the Puna Plateau: Implications for Cordilleran Plateau Evolution

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Ward, K. M.; Delph, J. R.; Zandt, G.; Beck, S. L.; Ducea, M. N.

2016-12-01

Quantifying well constrained plutonic to volcanic (P:V) ratios is inherently difficult because the tectonic processes that exhume intrusive bodies rarely preserve their extrusive equivalents. Conversely, active magmatic systems that have well-preserved volcanic deposits require sophisticated geophysical or geochemical approaches to estimate their plutonic roots and even when these sophisticated approaches are available, it is not always clear what constitutes a plutonic volume. Further complicating the enigmatic plutonic to volcanic relationship is the highly episodic nature of pluton emplacement where magmatic flare-ups produce several orders of magnitude more magmatism when compared against magmatic lulls. Despite this inherent difficulty, a growing body of independently measured P:V ratios (e.g. seismic tomography, geomorphic modeling, geological mapping/dating, and Zircon age spectra modeling) suggests the contribution of magmatic addition as an uplift mechanism in Cordilleran systems is much larger than is currently accepted. However, it remains unclear if these studies can be generalized to represent type behavior in Cordilleran systems or result from the non-uniform sampling imposed by the ability to measure large P:V ratios in only a few select and potentially anomalous regions of the American Cordillera. To better examine the role of magmatic processes in building Cordilleran high plateaus, we image the crustal seismic shear-wave velocity for an 800 km section (20.5°-28°S) of the active South American Cordillera (Puna Plateau). When placed in the context of existing geological and geophysical datasets, our seismic model reveals numerous mid-crustal low-velocity zones that we unambiguously interpret as the plutonic underpinnings associated with the voluminous silicic volcanics of the Puna Plateau. These larger P:V ratios are consistent with recent thermomechanical modeling of granitic magma intrusions that support the existence of long-lived, partially

Intracontinental Deformation in the NW Iranian Plateau and Comparisons with the Northern Margin of the Tibetan Plateau

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Chen, L.; Jiang, M.; Talebian, M.; Wan, B.; Ai, Y.; Ghods, A.; Sobouti, F.; Xiao, W.; Zhu, R.

2017-12-01

This study investigates the intracontinental deformation and its relationship with the structure of the crust and uppermost mantle in the NW Iranian plateau by combining new seismic and geological observations, to understand how this part of the plateau deformed to accommodate the Arabia-Eurasia plate collision and how the property of the lithosphere controls the deformation pattern. In contrast to the adjacent Anatolian block that exhibits westward large-scale extrusion, the northwesternmost part of the Iranian plateau shows dispersed intracontinental deformations with the development of numerous small-scale and discontinuous right-lateral strike-slip faults. The dispersed surface structures and deformation pattern correspond well to the active volcanism and seismically slow crust and uppermost mantle, and hence a weak lithosphere of the area. Further to the southeast are the western part of the Alborz Mountains and the southern Caspian Sea, both of which are characterized by stronger and more rigid lithosphere with relatively fast crust and uppermost mantle and absence of Quaternary volcanoes. A sharp Moho offset of 18 km has been imaged at the border of the Alborz and southern Caspian Sea using teleseismic receiver function data from a dense seismic array deployed under a collaborative project named "China-Iran Geological and Geophysical Survey in the Iranian Plateau (CIGSIP)". The sharp Moho offset and the minor undulations of the Moho on both sides indicate insignificant intracrustal deformation but mainly relative crustal movements between the Alborz Mountains and southern Caspian Sea, a behavior consistent with the relatively rigid nature of the lithosphere. Similar Moho offsets and lithospheric structures have been reported at the borders between the Kunlun Mountains and Qaidam or Tarim Basins in the northern margin of the Tibetan plateau, suggesting the occurrence of relative crustal movements with the effects of rigid continental lithosphere in the region

Happily Ever After: Plateauing as a Means for Long-Term Career Satisfaction.

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Montgomery, Denise L.

2002-01-01

Discusses plateauing as a means for long-term career satisfaction, Highlights include a literature review; what plateauing is and why it occurs, including career-based plateauing and life plateauing; some solutions to plateauing for librarians, including management changes and individual changes; and personal examples. (LRW)

Geochemistry of the Springfield Plateau aquifer of the Ozark Plateaus Province in Arkansas, Kansas, Missouri and Oklahoma, USA

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Adamski, J.C.

2000-01-01

Geochemical data indicate that the Springfield Plateau aquifer, a carbonate aquifer of the Ozark Plateaus Province in central USA, has two distinct hydrochemical zones. Within each hydrochemical zone, water from springs is geochemically and isotopically different than water from wells. Geochemical data indicate that spring water generally interacts less with the surrounding rock and has a shorter residence time, probably as a result of flowing along discrete fractures and solution openings, than water from wells. Water type throughout most of the aquifer was calcium bicarbonate, indicating that carbonate-rock dissolution is the primary geochemical process occurring in the aquifer. Concentrations of calcium, bicarbonate, dissolved oxygen and tritium indicate that most ground water in the aquifer recharged rapidly and is relatively young (less than 40 years). In general, field-measured properties, concentrations of many chemical constituents, and calcite saturation indices were greater in samples from the northern part of the aquifer (hydrochemical zone A) than in samples from the southern part of the aquifer (hydrochemical zone B). Factors affecting differences in the geochemical composition of ground water between the two zones are difficult to identify, but could be related to differences in chert content and possibly primary porosity, solubility of the limestone, and amount and type of cementation between zone A than in zone B. In addition, specific conductance, pH, alkalinity, concentrations of many chemical constituents and calcite saturation indices were greater in samples from wells than in samples from springs in each hydrochemical zone. In contrast, concentrations of dissolved oxygen, nitrite plus nitrate, and chloride generally were greater in samples from springs than in samples from wells. Water from springs generally flows rapidly through large conduits with minimum water-rock interactions. Water from wells flow through small fractures, which restrict

Revisiting Asian monsoon formation and change associated with Tibetan Plateau forcing: I. Formation

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Wu, Guoxiong; Liu, Yimin; Duan, Anmin; Bao, Qing [Chinese Academy of Sciences, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Beijing (China); Dong, Buwen [University of Reading, Department of Meteorology, National Centre for Atmospheric Science, Reading (United Kingdom); Liang, Xiaoyun [China Meteorological Administration, National Climate Center, Beijing (China); Yu, Jingjing [China Meteorological Administration, National Meteorological Information Center, Beijing (China)

2012-09-15

Numerical experiments with different idealized land and mountain distributions are carried out to study the formation of the Asian monsoon and related coupling processes. Results demonstrate that when there is only extratropical continent located between 0 and 120 E and between 20/30 N and the North Pole, a rather weak monsoon rainband appears along the southern border of the continent, coexisting with an intense intertropical convergence zone (ITCZ). The continuous ITCZ surrounds the whole globe, prohibits the development of near-surface cross-equatorial flow, and collects water vapor from tropical oceans, resulting in very weak monsoon rainfall. When tropical lands are integrated, the ITCZ over the longitude domain where the extratropical continent exists disappears as a consequence of the development of a strong surface cross-equatorial flow from the winter hemisphere to the summer hemisphere. In addition, an intense interaction between the two hemispheres develops, tropical water vapor is transported to the subtropics by the enhanced poleward flow, and a prototype of the Asian monsoon appears. The Tibetan Plateau acts to enhance the coupling between the lower and upper tropospheric circulations and between the subtropical and tropical monsoon circulations, resulting in an intensification of the East Asian summer monsoon and a weakening of the South Asian summer monsoon. Linking the Iranian Plateau to the Tibetan Plateau substantially reduces the precipitation over Africa and increases the precipitation over the Arabian Sea and the northern Indian subcontinent, effectively contributing to the development of the South Asian summer monsoon. (orig.)

Double subduction of continental lithosphere, a key to form wide plateau

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Replumaz, Anne; Funiciello, Francesca; Reitano, Riccardo; Faccenna, Claudio; Balon, Marie

2016-04-01

The mechanisms involved in the creation of the high and wide topography, like the Tibetan Plateau, are still controversial. In particular, the behaviour of the indian and asian lower continental lithosphere during the collision is a matter of debate, either thickening, densifying and delaminating, or keeping its rigidity and subducting. But since several decades seismicity, seismic profiles and global tomography highlight the lithospheric structure of the Tibetan Plateau, and make the hypotheses sustaining the models more precise. In particular, in the western syntaxis, it is now clear that the indian lithosphere subducts northward beneath the Hindu Kush down to the transition zone, while the asian one subducts southward beneath Pamir (e.g. Negredo et al., 2007; Kufner et al., 2015). Such double subduction of continental lithospheres with opposite vergence has also been inferred in the early collision time. Cenozoic volcanic rocks between 50 and 30 Ma in the Qiangtang block have been interpreted as related to an asian subduction beneath Qiangtang at that time (De Celles et al., 2011; Guillot and Replumaz, 2013). We present here analogue experiments silicone/honey to explore the subduction of continental lithosphere, using a piston as analogue of far field forces. We explore the parameters that control the subductions dynamics of the 2 continental lithospheres and the thickening of the plates at the surface, and compare with the Tibetan Plateau evolution. We show that a continental lithosphere is able to subduct in a collision context, even lighter than the mantle, if the plate is rigid enough. In that case the horizontal force due to the collision context, modelled by the piston push transmitted by the indenter, is the driving force, not the slab pull which is negative. It is not a subduction driving by the weight of the slab, but a subduction induced by the collision, that we could call "collisional subduction".

Shiga Toxin-Producing Escherichia coli in Plateau Pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China.

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Bai, Xiangning; Zhang, Wang; Tang, Xinyuan; Xin, Youquan; Xu, Yanmei; Sun, Hui; Luo, Xuelian; Pu, Ji; Xu, Jianguo; Xiong, Yanwen; Lu, Shan

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) are an emerging group of zoonotic pathogens. Ruminants are the natural reservoir of STEC. In this study we determined the prevalence and characteristics of the STEC in plateau pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China. A total of 1116 pika samples, including 294 intestinal contents samples, 317 fecal samples, and 505 intestinal contents samples, were collected from May to August in the years 2012, 2013, and 2015, respectively. Twenty-one samples (1.88%) yielded at least one STEC isolate; in total, 22 STEC isolates were recovered. Thirteen different O serogroups and 14 serotypes were identified. One stx 1 subtype (stx 1a) and three stx 2 subtypes (stx 2a, stx 2b, and stx 2d) were present in the STEC isolates. Fifteen, fourteen, and three STEC isolates harbored the virulence genes ehxA, subA, and astA, respectively. Adherence-associated genes iha and saa were, respectively, present in 72.73 and 68.18% of the STEC isolates. Twenty antibiotics were active against all the STEC isolates; all strains were resistant to penicillin G, and some to cephalothin or streptomycin. The 22 STEC isolates were divided into 16 pulsed-field gel electrophoresis patterns and 12 sequence types. Plateau pikas may play a role in the ongoing circulation of STEC in the Qinghai-Tibetan plateau. This study provides the first report on STEC in plateau pikas and new information about STEC reservoirs in wildlife. Based on the serotypes, virulence gene profiles and multi-locus sequence typing (MLST) analysis, the majority of these pika STECs may pose a low public health risk.

Complex responses of spring alpine vegetation phenology to snow cover dynamics over the Tibetan Plateau, China.

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Wang, Siyuan; Wang, Xiaoyue; Chen, Guangsheng; Yang, Qichun; Wang, Bin; Ma, Yuanxu; Shen, Ming

2017-09-01

Snow cover dynamics are considered to play a key role on spring phenological shifts in the high-latitude, so investigating responses of spring phenology to snow cover dynamics is becoming an increasingly important way to identify and predict global ecosystem dynamics. In this study, we quantified the temporal trends and spatial variations of spring phenology and snow cover across the Tibetan Plateau by calibrating and analyzing time series of the NOAA AVHRR-derived normalized difference vegetation index (NDVI) during 1983-2012. We also examined how snow cover dynamics affect the spatio-temporal pattern of spring alpine vegetation phenology over the plateau. Our results indicated that 52.21% of the plateau experienced a significant advancing trend in the beginning of vegetation growing season (BGS) and 34.30% exhibited a delaying trend. Accordingly, the snow cover duration days (SCD) and snow cover melt date (SCM) showed similar patterns with a decreasing trend in the west and an increasing trend in the southeast, but the start date of snow cover (SCS) showed an opposite pattern. Meanwhile, the spatial patterns of the BGS, SCD, SCS and SCM varied in accordance with the gradients of temperature, precipitation and topography across the plateau. The response relationship of spring phenology to snow cover dynamics varied within different climate, terrain and alpine plant community zones, and the spatio-temporal response patterns were primarily controlled by the long-term local heat-water conditions and topographic conditions. Moreover, temperature and precipitation played a profound impact on diverse responses of spring phenology to snow cover dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

Topographic heterogeneity and temperature amplitude explain species richness patterns of birds in the Qinghai-Tibetan Plateau.

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Zhang, Chunlan; Quan, Qing; Wu, Yongjie; Chen, Youhua; He, Peng; Qu, Yanhua; Lei, Fumin

2017-04-01

Large-scale patterns of species richness have gained much attention in recent years; however, the factors that drive high species richness are still controversial in local regions, especially in highly diversified montane regions. The Qinghai-Tibetan Plateau (QTP) and the surrounding mountains are biodiversity hot spots due to a high number of endemic montane species. Here, we explored the factors underlying this high level of diversity by studying the relationship between species richness and environmental variables. The richness patterns of 758 resident bird species were summarized at the scale of 1°×1° grid cell at different taxonomic levels (order, family, genus, and species) and in different taxonomic groups (Passeriformes, Galliformes, Falconiformes, and Columbiformes). These richness patterns were subsequently analyzed against habitat heterogeneity (topographical heterogeneity and land cover), temperature amplitude (annual temperature, annual precipitation, precipitation seasonality, and temperature seasonality) and a vegetation index (net primary productivity). Our results showed that the highest richness was found in the southeastern part of the QTP, the eastern Himalayas. The lowest richness was observed in the central plateau of the QTP. Topographical heterogeneity and temperature amplitude are the primary factors that explain overall patterns of species richness in the QTP, although the specific effect of each environmental variable varies between the different taxonomic groups depending on their own evolutionary histories and ecological requirements. High species richness in the southeastern QTP is mostly due to highly diversified habitat types and temperature zones along elevation gradients, whereas the low species richness in the central plateau of the QTP may be due to environmental and energetic constraints, as the central plateau is harsh environment.

Chemical erosion and hydrologic budget for the Susure karst plateau

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Nikić Zoran

2010-01-01

Full Text Available The karst plateau of Susure, about 4.5 km2 in surface area, is situated on the Jadovnik eastern offset, western Serbia. The plateau is a morphologic unit higher 15 m to 30 m than the surrounding terrain. The unit consists of crushed and karstified Middle Triassic limestones. Numerous hydrogeological and geomorphologic features of the plateau are attractive for visitors in this economically underdeveloped country. Rocks building up the surrounding terrain are largely peridotites. Surface streams flow neither into nor off the plateau. Atmospheric precipitations discharge to evapotanspiration and filtration underground. More than eighteen constant springs at the limestone/peridotite tectonic contact drain fracture aquifers on the karst plateau border. Measured precipitations and springflows were the input and output data for accounting water budget of an aquifer of Middle Triassic limestones in the Susure plateau.

Deformation styles and exhumation patterns in the Northern Iranian Plateau: New results from integrated balanced cross sections and low-temperature thermochronology (AHe and ZHe)

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Balling, Philipp; Ballato, Paolo; Dunkl, István; Zeillinger, Gerold; Heidarzadeh, Ghasem; Ghasemi, Mohammad; Strecker, Manfred R.

2014-05-01

The Iranian Plateau is situated in the collision zone between the Arabian and Eurasian plates and forms a NW-SE elongated, 40- to 50-km-thick crustal block, delimited to the north by the Urmieh Dokhtar Volcanic Zone and to south by the High Zagros Mountains. The plateau is characterized by a series of basins and mountain ranges bounded by reverse and transpressive faults. These mountain ranges reflect a history of strong collisional deformation, with intensely faulted and folded Pre-Cambrian (basement) to Miocene (terrestrial sediments of the Upper Red Formation) rocks. Based on the structural evolution, high mean elevation of 2 km, and a crustal thickness of up to 56 km, the realm of the present-day plateau must have absorbed a significant fraction of past plate convergence between Eurasia and Arabia. However, according to seismic and GPS data active deformation is rather limited. In addition, the exact timing and style of deformation, the extent of crustal shortening and thickening on the northern Iranian Plateau during continental collision remain unclear. To address these issues we collected structural data and modeled deformation scenarios cross four mountain ranges that constitute the northern margin of the Iranian Plateau (NW Iran). The Tarom, Mah Neshan and Sultanije mountain ranges are NW-SE oriented, while the northernmost (Bozgosh) is E-W aligned. Due to the lack of subsurface data, several forward and backward models were generated with MOVE (Midland Valley, structural modelling software). The model with the simplest and most robust geological explanation of the field data was chosen. In addition, we combined our structural work with an apatite (U-Th)/He study (AHe) along two transects (Bozgosh, Mah Neshan) and Zircon (U-Th)/He data (ZHe) on higher exhumed locations. In the northern sector of the plateau late Cretaceous (or Paleocene?) rocks had been deposited unconformably onto older, deformed rocks. This suggests that the Arabia-Eurasia collision was

A preliminary study of the heating effect of the Tibetan Plateau.

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Yonghui Yao

Full Text Available The immense and towering Tibetan Plateau acts as a heating source and, thus, deeply shapes the climate of the Eurasian continent and even the whole world. However, due to the scarcity of meteorological observation stations and very limited climatic data, little is quantitatively known about the heating effect of the plateau and its implications. This paper firstly collects climate data (2001-2007 from 109 observation stations and MODIS-based estimated monthly mean temperature data in the plateau and the neighboring Sichuan Basin, and conducts correlation and simple linear regression to reveal the altitudinal pattern of temperature. Then, according to the linear relationships of temperature and altitude for each month, it compares air temperature differences on the same elevation between the main plateau and surrounding mountains and the Sichuan Basin so as to quantify the heating effect and discuss its implication on timberline of the plateau. The results show that: 1 the heating effect of the plateau is significant. The temperature of the main plateau area was higher than that of free air on the same elevation above the neighboring areas; on the elevation of 4500 m (the main plateau, temperature is 1-6°C higher in the main Plateau than over the Sichuan Basin for different months and 5.9-10.7°C higher than in the Qilian Mountains in the northeastern corner of the plateau. 2 Even at altitudes of 5000-6000 m in the main Plateau, there are 4 months with a mean temperature above 0°C. The mean temperature of the warmest month (July can reach 10°C at about 4600-4700 m. This may help explain why the highest timberline in the northern hemisphere is on the southeastern Tibetan Plateau.

Changes in spatial patterns of Caragana stenophylla along a climatic drought gradient on the Inner Mongolian Plateau.

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Xie, Li-Na; Guo, Hong-Yu; Gabler, Christopher A; Li, Qing-Fang; Ma, Cheng-Cang

2015-01-01

Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, "nurse effects" of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophylla across semi-arid, arid, and intensively arid zones. Our results showed that patches of C. stenophylla populations shifted from a random to a clumped spatial pattern towards drier environments. Seed density and seedling survival rate of C. stenophylla decreased from the semi-arid zone to the intensively arid zone. Across the three zones, there were more C. stenophylla seeds and seedlings underneath shrub canopies than outside shrub canopies; and in the intensively arid zone, there were almost no seeds or seedlings outside shrub canopies. Transpiration rates of outer-canopy leaves and WUE of both outer-canopy and inner-canopy leaves increased from the semi-arid zone to the intensively arid zone. In the intensively arid zone, transpiration rates and WUE of inner-canopy leaves were significantly lower and higher, respectively, than those of outer-canopy leaves. We conclude that, as drought stress increased, seed density decreased, seed proportions inside shrubs increased, and "nurse effects" of shrubs on seedlings became more important. These factors, combined with water-saving characteristics associated with clumped spatial patterns, are likely driving the changes in C. stenophylla spatial patterns.

The Pajarito Plateau: A bibliography

Science.gov (United States)

Mathien, Frances Joan; Steen, Charlie R.; Allen, Craig D.

1993-01-01

This bibliography is the result of two initially independent projects. As the consulting archaeologist at Los Alamos National Laboratory (LANL), Charlie R. Steen collected entries at the suggestion of the staff of the Environmental Surveillance Group of the Health, Safety, and Environmental Division, HSE-8. The primary purpose was to aid the staff in evaluating cultural resources on LANL lands. In addition to works that related to the archaeology and history of the area, Steen included notations of a few books and articles in other fields such as geology and natural history. It was hoped that they also would be of value to other organizations and to students of past human activities on the Pajarito Plateau.At the same time, the National Park Service (NPS) was planning a major survey of Bandelier National Monument (BNM). As part of this plan, the author was asked to prepare a background document that described research previously carried out in the area, including an annotated bibliography. Although the survey would be limited to the park boundaries, the larger Pajarito Plateau is a more logical study area from physiographic, environmental, and cultural perspectives; hence the focus was on this larger region. Mathien (1986) also included some references to natural resources studies, particularly those initiated by NPS within Bandelier National Monument.Both bibliographies were made available to Colleen Olinger and Beverly Larson of the Health and Environmental Services Group at Los Alamos. They realized that while neither was complete, each included entries missing from the other. Larson suggested the two bibliographies be combined. (At this time, Craig Allen was studying the landscape of the Jemez Mountains [Allen 1984c, 1989]. His investigations included much detailed information on natural resource studies and were added in 1991 and 1992.)To limit the scope of their work, Steen and Mathien had chosen their parameter: the Pajarito Plateau. Geographically, the

The impact of afforestation on soil organic carbon sequestration on the Qinghai Plateau, China.

Science.gov (United States)

Shi, Sheng-wei; Han, Peng-fei; Zhang, Ping; Ding, Fan; Ma, Cheng-lin

2015-01-01

Afforestation, the conversion of non-forested land into forest, is widespread in China. However, the dynamics of soil organic carbon (SOC) after afforestation are not well understood, especially in plateau climate zones. For a total of 48 shrub- and/or tree-dominated afforestation sites on the Qinghai Plateau, Northwestern China, post-afforestation changes in SOC, total nitrogen (TN), the carbon-to-nitrogen ratio (C/N) and soil bulk density (BD) were investigated to a soil depth of 60 cm using the paired-plots method. SOC and TN accumulated at rates of 138.2 g C m(-2) yr(-1) and 4.6 g N m(-2) yr(-1), respectively, in shrub-dominated afforestation sites and at rates of 113.3 g C m(-2) yr(-1) and 6.7 g N m(-2) yr(-1), respectively, in tree-dominated afforestation sites. Soil BD was slightly reduced in all layers in the shrub-dominated afforestation plots, and significantly reduced in soil layers from 0-40cm in the tree-dominated afforestation plots. The C/N ratio was higher in afforested sites relative to the reference sites. SOC accumulation was closely related to TN accumulation following afforestation, and the inclusion of N-fixing species in tree-dominated afforestation sites additionally increased the soil accumulation capacity for SOC (p sequestration. This study improves our understanding of the mechanisms underlying SOC and TN accumulation in a plateau climate, and provides evidence on the C sequestration potentials associated with forestry projects in China.

Shear-Wave Splitting and Crustal Anisotropy in the Shillong-Mikir Plateau of Northeast India

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Bora, Dipok K.; Hazarika, Devajit; Paul, Arpita; Borah, Kajaljyoti; Borgohain, Jayanta Madhab

2018-01-01

Seismic anisotropy of crust beneath the Shillong-Mikir Plateau and the surrounding regions of northeast India have been investigated with the help of splitting analysis of S-wave of local earthquakes. We estimate a total 83 pairs of splitting parameters ( Φ and δt) from 67 local shallow focus earthquakes (depth ≤ 32 km) recorded by the 10 broadband seismological stations operated in the study region. The results show delay times ranging from 0.02 to 0.2 s, which correspond to anisotropy up to 4%, suggesting significant strength of anisotropy in the study region. Fast polarization direction ( Φ) in the Shillong Plateau shows mostly NW-SE trend in the western part and NE-SW trend in the northern part. Φs near Kopili fault (KF) follows NW-SE trend. Φ at most of the stations in the study region is consistent with the local stress orientation, suggesting that the anisotropy is mainly caused by preferentially aligned cracks responding to the stress field. On the other hand, anisotropy observed near the KF is due to aligned macroscopic fracture related to strike-slip movement in the fault zone.

Parhelic-like circle from light scattering in Plateau borders

Energy Technology Data Exchange (ETDEWEB)

Tufaile, A., E-mail: tufaile@usp.br; Tufaile, A.P.B.

2015-03-06

We are reporting a new simple optical element to generate halos. We have observed interesting patterns of light scattering in Plateau borders in foams. In analogy to the atmospheric phenomena known as parhelic circle, sun dogs, and sun pillars, we have named the features of the patterns observed as parlaseric circle, laser dogs, and laser pillars. The triangular symmetry of the Plateau borders is analogous to the hexagonal symmetry of ice crystals which produce these atmospheric phenomena. Working with one Plateau border at a time, we have observed wave optics phenomena that are not perceived in the atmospheric phenomena, such as diffraction and interference. - Highlights: • We obtained halo formation from light scattering in a Plateau border using an experiment. • We explained halo formation using geometrical theory of diffraction. • An optical element based on a Plateau border is proposed. • We compared some aspects of the parhelic circle with the parlaseric circle.

Crustal structure of the rifted volcanic margins and uplifted plateau of Western Yemen from receiver function analysis

Science.gov (United States)

Ahmed, Abdulhakim; Tiberi, Christel; Leroy, Sylvie; Stuart, Graham W.; Keir, Derek; Sholan, Jamal; Khanbari, Khaled; Al-Ganad, Ismael; Basuyau, Clémence

2013-06-01

We analyse P-wave receiver functions across the western Gulf of Aden and southern Red Sea continental margins in Western Yemen to constrain crustal thickness, internal crustal structure and the bulk seismic velocity characteristics in order to address the role of magmatism, faulting and mechanical crustal thinning during continental breakup. We analyse teleseismic data from 21 stations forming the temporary Young Conjugate Margins Laboratory (YOCMAL) network together with GFZ and Yemeni permanent stations. Analysis of computed receiver functions shows that (1) the thickness of unextended crust on the Yemen plateau is ˜35 km; (2) this thins to ˜22 km in coastal areas and reaches less than 14 km on the Red Sea coast, where presence of a high-velocity lower crust is evident. The average Vp/Vs ratio for the western Yemen Plateau is 1.79, increasing to ˜1.92 near the Red Sea coast and decreasing to 1.68 for those stations located on or near the granitic rocks. Thinning of the crust, and by inference extension, occurs over a ˜130-km-wide transition zone from the Red Sea and Gulf of Aden coasts to the edges of the Yemen plateau. Thinning of continental crust is particularly localized in a <30-km-wide zone near the coastline, spatially co-incident with addition of magmatic underplate to the lower crust, above which on the surface we observe the presence of seaward dipping reflectors (SDRs) and thickened Oligo-Miocene syn-rift basaltic flows. Our results strongly suggest the presence of high-velocity mafic intrusions in the lower crust, which are likely either synrift magmatic intrusion into continental lower crust or alternatively depleted upper mantle underplated to the base of the crust during the eruption of the SDRs. Our results also point towards a regional breakup history in which the onset of rifting was synchronous along the western Gulf of Aden and southern Red Sea volcanic margins followed by a second phase of extension along the Red Sea margin.

Fate of Glaciers in the Tibetan Plateau by 2100

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Duan, K.

2017-12-01

As the third polar on the Earth, the Tibetan plateau holds more than 40,000 glaciers which have experienced a rapid retreat in recent decades. The variability of equilibrium line altitude (ELA) indicates expansion and wastage of glacier directly. Here we simulated the ELA variability in the Tibetan Plateau based on a full surface energy and mass balance model. The simulation results are agreement with the observations. The ELAs have risen at a rate of 2-8m/a since 1970 throughout the Plateau, especially in the eastern Plateau where the ELAs have risen to or over the top altitude of glacier, indicating the glaciers are accelerating to melting over there. Two glaciers, XD glacier in the center of the Plateau and Qiyi glacier in the Qilian Mountain, are chosen to simulate its future ELA variability in the scenarios of RCP2.6, RCP4.5 and RCP 8.5 given by IPCC. The results show the ELAs will arrive to its maximum in around 2040 in RCP2.6, while the ELAs will be over the top altitude of glaciers in 2035-2045 in RCP4.5 and RCP8.5, suggesting the glaciers in the eastern Plateau will be melting until the disappear of the glaciers by the end of 2100.

40 CFR 81.162 - Northeast Plateau Intrastate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Northeast Plateau Intrastate Air... Air Quality Control Regions § 81.162 Northeast Plateau Intrastate Air Quality Control Region. The Northeast Plateau Intrastate Air Quality Control Region (California) consists of the territorial area...

HANFORD SITE CENTRAL PLATEAU CLEANUP COMPLETION STRATEGY

International Nuclear Information System (INIS)

Bergman, T.B.

2011-01-01

Cleanup of the Hanford Site is a complex and challenging undertaking. The U.S. Department of Energy (DOE) has developed a comprehensive vision for completing Hanford's cleanup mission including transition to post-cleanup activities. This vision includes 3 principle components of cleanup: the ∼200 square miles ofland adjacent to the Columbia River, known as the River Corridor; the 75 square miles of land in the center of the Hanford Site, where the majority of the reprocessing and waste management activities have occurred, known as the Central Plateau; and the stored reprocessing wastes in the Central Plateau, the Tank Wastes. Cleanup of the River Corridor is well underway and is progressing towards completion of most cleanup actions by 2015. Tank waste cleanup is progressing on a longer schedule due to the complexity of the mission, with construction of the largest nuclear construction project in the United States, the Waste Treatment Plant, over 50% complete. With the progress on the River Corridor and Tank Waste, it is time to place increased emphasis on moving forward with cleanup of the Central Plateau. Cleanup of the Hanford Site has been proceeding under a framework defmed in the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). In early 2009, the DOE, the State of Washington Department of Ecology, and the U.S. Environmental Protection Agency signed an Agreement in Principle in which the parties recognized the need to develop a more comprehensive strategy for cleanup of the Central Plateau. DOE agreed to develop a Central Plateau Cleanup Completion Strategy as a starting point for discussions. This DOE Strategy was the basis for negotiations between the Parties, discussions with the State of Oregon, the Hanford Advisory Board, and other Stakeholder groups (including open public meetings), and consultation with the Tribal Nations. The change packages to incorporate the Central Plateau Cleanup Completion Strategy were signed by the

Does the climate warming hiatus exist over the Tibetan Plateau?

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Duan, Anmin; Xiao, Zhixiang

2015-09-02

The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25 °C decade(-1)), compared with that during 1980-1997 (0.21 °C decade(-1)). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau.

Hydrogeochemical Characteristics and Evolution of Hot Springs in Eastern Tibetan Plateau Geothermal Belt, Western China: Insight from Multivariate Statistical Analysis

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Zheming Shi

2017-01-01

Full Text Available The eastern Tibetan Plateau geothermal belt is one of the important medium-high temperature geothermal belts in China. However, less work has been done on the hydrochemical characteristic and its geological origin. Understanding the chemical characteristics and the hydrochemical evolution processes is important in evaluating the geothermal energy potential in this area. In the present study, we discussed the hydrochemical properties and their origins of 39 hot springs located in the eastern Tibetan Plateau geothermal belt (Kangding-Litang-Batang geothermal belt. Cluster analysis and factor analysis are employed to character the hydrochemical properties of hot springs in different fault zones and the possible hydrochemical evolution processes of these hot springs. Our study shows that the hot springs can be divided into three groups based on their locations. The hot springs in the first group mainly originate from the volcanic rock and the springs in the second group originate from the metamorphic rock while the springs in the third group originate from the result of mixture of shallow water. Water-rock interaction, cation exchange, and the water environment are the three dominant factors that control the hydrochemical evolution process in the eastern Tibetan Plateau. These results are also in well agreement with the isotopic and chemical analysis.

Geochemical characteristics of the Jos-Plateau Basalts, North ...

African Journals Online (AJOL)

The Jos Plateau basalts, present Zr/Nb ratios (2.4-3.0) comparable to those of the alkali basalts of the lower Benue valley, and of the Cameroon volcanic line, suggesting that they were possibly derived from the same mantle source. Keywords: Jos Plateau, alkali basalt, mantle, partial melting, incompatible elements.

Tackling the Challenge of Deep Vadose Zone Remediation at the Hanford Site

Science.gov (United States)

Morse, J. G.; Wellman, D. M.; Gephart, R.

2010-12-01

The Central Plateau of the Hanford Site in Washington State contains some 800 waste disposal sites where 1.7 trillion liters of contaminated water was once discharged into the subsurface. Most of these sites received liquids from the chemical reprocessing of spent uranium fuel to recover plutonium. In addition, 67 single shell tanks have leaked or are suspected to have leaked 3.8 million liters of high alkali and aluminate rich cesium-contaminated liquids into the sediment. Today, this inventory of subsurface contamination contains an estimated 550,000 curies of radioactivity and 150 million kg (165,000 tons) of metals and hazardous chemicals. Radionuclides range from mobile 99Tc to more immobilized 137Cs, 241Am, uranium, and plutonium. A significant fraction of these contaminants likely remain within the deep vadose zone. Plumes of groundwater containing tritium, nitrate, 129I and other contaminants have migrated through the vadose zone and now extend outward from the Central Plateau to the Columbia River. During most of Hanford Site history, subsurface studies focused on groundwater monitoring and characterization to support waste management decisions. Deep vadose zone studies were not a priority because waste practices relied upon that zone to buffer contaminant releases into the underlying aquifer. Remediation of the deep vadose zone is now central to Hanford Site cleanup because these sediments can provide an ongoing source of contamination to the aquifer and therefore to the Columbia River. However, characterization and remediation of the deep vadose zone pose some unique challenges. These include sediment thickness; contaminant depth; coupled geohydrologic, geochemical, and microbial processes controlling contaminant spread; limited availability and effectiveness of traditional characterization tools and cleanup remedies; and predicting contaminant behavior and remediation performance over long time periods and across molecular to field scales. The U

Crustal deformation mechanism in southeastern Tibetan Plateau: Insights from numerical modeling

Science.gov (United States)

Li, Y.; Liu, S.; Chen, L.

2017-12-01

The Indo-Asian collision developed the complicated crustal deformation around the southeastern Tibetan plateau. Numerous models have proposed to explain the crustal deformation, but the mechanism remains controversial, especially the increasing multi-geophysics data, which demonstrate the existence of lower velocity, lower resistivity and high conductivity, implying that lower crustal flow is responsible for the crustal deformation, arguing for the lower crust flow model. To address the relations between the crust flow and the surface deformation, we employ a three-dimensional viscoelastic finite model to investigate the possible influence on the surface deformation, and discuss the stress field distribution under the model. Our preliminary results suggest that lower crustal flow plays an important role in crustal deformation in southeastern Tibetan plateau. The best fitting is achieved when the flow velocity of the lower crust is approximately 10-11 mm/a faster than that of the upper crust. Crustal rheological properties affect regional crustal deformation, when the viscosity of the middle and lower crust in the South China block reaches 1022 and 1023 Pa.s, respectively; the predicted match observations well, especially for the magnitude within the South China block. The maximum principal stress field exhibits clear zoning, gradually shifting from an approximately east-west orientation in the northern Bayan Har block to southeast in the South China block, southwest in the western Yunnan block, and a radially divergent distribution in the Middle Yunnan and Southern Yunnan blocks.

The Colorado Plateau II: biophysical, socioeconomic, and cultural research

Science.gov (United States)

Mattson, David J.; van Riper, Charles

2005-01-01

The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through grazing and the wildland-urban interface issues, to parameters of climate change on the Plateau. The book also introduces economic perspectives by considering shifting patterns and regional disparities in the Colorado Plateau economy. A series of chapters on mountain lions explores the human-wildland interface. These chapters deal with the entire spectrum of challenges associated with managing this large mammal species in Arizona and on the Colorado Plateau, conveying a wealth of timely information of interest to wildlife managers and enthusiasts. Another provocative set of chapters on biophysical resources explores the management of forest restoration, from the micro scale all the way up to large-scale GIS analyses of ponderosa pine ecosystems on the Colorado Plateau. Given recent concerns for forest health in the wake of fires, severe drought, and bark-beetle infestation, these chapters will prove enlightening for forest service, park service, and land management professionals at both the federal and state level, as well as general readers interested in how forest management practices will ultimately affect their recreation activities. With broad coverage that touches on topics as diverse as movement patterns of rattlesnakes, calculating watersheds, and rescuing looted rockshelters, this volume stands as a compendium of cutting-edge research on the Colorado Plateau that offers a wealth of insights for many scholars.

Soil carbon sequestration potential for "grain for green" project in Loess Plateau, China

Science.gov (United States)

Chang, R.; Fu, B.; Liu, Gaisheng; Liu, S.

2011-01-01

Conversion of cropland into perennial vegetation land can increase soil organic carbon (SOC) accumulation, which might be an important mitigation measure to sequester carbon dioxide from the atmosphere. The “Grain for Green” project, one of the most ambitious ecological programmes launched in modern China, aims at transforming the low-yield slope cropland into grassland and woodland. The Loess Plateau in China is the most important target of this project due to its serious soil erosion. The objectives of this study are to answer three questions: (1) what is the rate of the SOC accumulation for this “Grain for Green” project in Loess Plateau? (2) Is there a difference in SOC sequestration among different restoration types, including grassland, shrub and forest? (3) Is the effect of restoration types on SOC accumulation different among northern, middle and southern regions of the Loess Plateau? Based on analysis of the data collected from the literature conducted in the Loess Plateau, we found that SOC increased at a rate of 0.712 TgC/year in the top 20 cm soil layer for 60 years under this project across the entire Loess Plateau. This was a relatively reliable estimation based on current data, although there were some uncertainties. Compared to grassland, forest had a significantly greater effect on SOC accumulation in middle and southern Loess Plateau but had a weaker effect in the northern Loess Plateau. There were no differences found in SOC sequestration between shrub and grassland across the entire Loess Plateau. Grassland had a stronger effect on SOC sequestration in the northern Loess Plateau than in the middle and southern regions. In contrast, forest could increase more SOC in the middle and southern Loess Plateau than in the northern Loess Plateau, whereas shrub had a similar effect on SOC sequestration across the Loess Plateau. Our results suggest that the “Grain for Green” project can significantly increase the SOC storage in Loess Plateau

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

Science.gov (United States)

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

2017-06-18

To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

Lateral variations in the crustal structure of the Indo-Eurasian collision zone

Science.gov (United States)

Gilligan, Amy; Priestley, Keith

2018-05-01

The processes involved in continental collisions remain contested, yet knowledge of these processes is crucial to improving our understanding of how some of the most dramatic features on Earth have formed. As the largest and highest orogenic plateau on Earth today, Tibet is an excellent natural laboratory for investigating collisional processes. To understand the development of the Tibetan Plateau we need to understand the crustal structure beneath both Tibet and the Indian Plate. Building on previous work, we measure new group velocity dispersion curves using data from regional earthquakes (4424 paths) and ambient noise data (5696 paths), and use these to obtain new fundamental mode Rayleigh Wave group velocity maps for periods from 5-70 s for a region including Tibet, Pakistan and India. The dense path coverage at the shortest periods, due to the inclusion of ambient noise measurements, allows features of up to 100 km scale to be resolved in some areas of the collision zone, providing one of the highest resolution models of the crust and uppermost mantle across this region. We invert the Rayleigh wave group velocity maps for shear wave velocity structure to 120 km depth and construct a 3D velocity model for the crust and uppermost mantle of the Indo-Eurasian collision zone. We use this 3D model to map the lateral variations in the crust and in the nature of the crust-mantle transition (Moho) across the Indo-Eurasian collision zone. The Moho occurs at lower shear velocities below north eastern Tibet than it does beneath western and southern Tibet and below India. The east-west difference across Tibet is particularly apparent in the elevated velocities observed west of 84° E at depths exceeding 90 km. This suggests that Indian lithosphere underlies the whole of the Plateau in the west, but possibly not in the east. At depths of 20-40 km our crustal model shows the existence of a pervasive mid-crustal low velocity layer (˜10% decrease in velocity, Vs Vsv. The

The Central Eurasia collision zone: insights from a neotectonic study

Science.gov (United States)

Tunini, Lavinia; Jiménez-Munt, Ivone; Fernandez, Manel; Vergés, Jaume

2017-04-01

In this study, we explore the neotectonic deformation in the whole Central Eurasia, including both the India-Eurasia and the Arabia-Eurasia collision zones, by using the thin-sheet approach in which the lithosphere strength is calculated from the lithosphere structure and thermal regime. We investigate the relative contributions of the lithospheric structure, rheology, boundary conditions, and friction coefficient on faults on the predicted velocity and stress fields. The resulting models have been evaluated by comparing the predictions with available data on seismic deformation, stress directions and GPS velocities. A first order approximation of the velocity and stress directions is obtained, reproducing the counter-clockwise rotation of Arabia and Iran, the westward escape of Anatolia, and the eastward extrusion of the northern Tibetan Plateau. To simulate the observed extensional faults within Tibet a weaker lithosphere is required, provided by a change in the rheological parameters or a reduction of the lithosphere thickness in NE-Tibet. The temperature increase generated by the lithospheric thinning below the Tibetan Plateau would also allow reconciling the model with the high heat flow and low mantle seismic velocities observed in the area. Besides the large scale, this study offers a coherent result in regions with little or no data coverage, as in the case of the Arabia-India inter-collision zone, over large areas of Pakistan and entire Afghanistan. The study is supported by MITE (CGL2014-59516-P) and WE-ME (PIE-CSIC-201330E111) projects.

Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia: I. Comparisons between plateau, slope and valley floor

Directory of Open Access Journals (Sweden)

M. G. Hodnett

1997-01-01

Full Text Available Soil water storage was monitored in three landscape elements in the forest (plateau, slope and valley floor over a 3 year period to identify differences in sub-surface hydrological response. Under the plateau and slope, the changes of storage were very similar and there was no indication of surface runoff on the slope. The mean maximum seasonal storage change was 156 mm in the 2 m profile but it was clear that, in the dry season, the forest was able to take up water from below 3.6 m. Soil water availability was low. Soil water storage changes in the valley were dominated by the behaviour of a shallow water table which, in normal years, varied between 0.1 m below the surface at the end of the wet season and 0.8 m at the end of the dry season. Soil water storage changes were small because root uptake was largely replenished by groundwater flow towards the stream. The groundwater behaviour is controlled mainly by the deep drainage from beneath the plateau and slope areas. The groundwater gradient beneath the slope indicated that recharge beneath the plateau and slope commences only after the soil water deficits from the previous dry season have been replenished. Following a wet season with little recharge, the water table fell, ceasing to influence the valley soil water storage, and the stream dried up. The plateau and slope, a zone of very high porosity between 0.4 and 1.1 m, underlain by a less conductive layer, is a probable route for interflow during, and for a few hours after, heavy and prolonged rainfall.

Field report: Research along the Yarlung Suture Zone in Southern Tibet, a persistent geological frontier

Directory of Open Access Journals (Sweden)

Andrew K. Laskowski

2018-03-01

Full Text Available The Yarlung Suture Zone in Southern Tibet marks the boundary between India and Asia–formerly separated by an ocean basin–and is a critical record of the tectonic processes that created the Tibetan Plateau. The Yarlung Suture Zone is also a frontier research area, as difficulty of access has limited research activity, providing ample opportunities for new discoveries. This paper documents field research conducted by the authors along the Yarlung suture zone in eastern Xigaze (Shigatse, Rikaze County, ∼250 km west of the city of Lhasa, in July 2017. The goal of this research was to map the Suture Zone structure in detail, and more specifically to understand the branching relationships between two major fault systems—the Great Counter Thrust and Gangdese Thrust. A summary of early geological exploration is included to provide context for this research.

Teaching Rayleigh–Plateau instabilities in the laboratory

International Nuclear Information System (INIS)

Fragkopoulos, A A; Ellis, P W; Fernandez-Nieves, A

2015-01-01

The breakup of a liquid jet into spherical droplets via the Rayleigh–Plateau instability is a common and fundamental part of fluid mechanics. However, teaching this instability in a laboratory setting is challenging, requiring sophisticated methods to generate and study the jet dynamics. Recently, toroidal droplets were shown to break into one or more spherical droplets in the thin-drop limit via the Rayleigh–Plateau instability. We propose a simple experimental setup to generate toroidal droplets that break up on the order of tens of seconds, allowing for easy video capture using a basic CCD camera. With this setup, it is possible to quantify the Rayleigh–Plateau instability in a pedagogical laboratory setting. In addition, the role of curvature on jet breakup can be explored using thick toroidal droplets. We envision this setup as a powerful teaching tool for one of the most fundamental fluid dynamics processes. (paper)

Influence of Western Tibetan Plateau Summer Snow Cover on East Asian Summer Rainfall

Science.gov (United States)

Wang, Zhibiao; Wu, Renguang; Chen, Shangfeng; Huang, Gang; Liu, Ge; Zhu, Lihua

2018-03-01

The influence of boreal winter-spring eastern Tibetan Plateau snow anomalies on the East Asian summer rainfall variability has been the focus of previous studies. The present study documents the impacts of boreal summer western and southern Tibetan Plateau snow cover anomalies on summer rainfall over East Asia. Analysis shows that more snow cover in the western and southern Tibetan Plateau induces anomalous cooling in the overlying atmospheric column. The induced atmospheric circulation changes are different corresponding to more snow cover in the western and southern Tibetan Plateau. The atmospheric circulation changes accompanying the western Plateau snow cover anomalies are more obvious over the midlatitude Asia, whereas those corresponding to the southern Plateau snow cover anomalies are more prominent over the tropics. As such, the western and southern Tibetan Plateau snow cover anomalies influence the East Asian summer circulation and precipitation through different pathways. Nevertheless, the East Asian summer circulation and precipitation anomalies induced by the western and southern Plateau snow cover anomalies tend to display similar distribution so that they are more pronounced when the western and southern Plateau snow cover anomalies work in coherence. Analysis indicates that the summer snow cover anomalies over the Tibetan Plateau may be related to late spring snow anomalies due to the persistence. The late spring snow anomalies are related to an obvious wave train originating from the western North Atlantic that may be partly associated with sea surface temperature anomalies in the North Atlantic Ocean.

Stratigraphy of the Bandelier Tuff in the Pajarito Plateau. Applications to waste management

International Nuclear Information System (INIS)

Crowe, B.M.; Linn, G.W.; Heiken, G.; Bevier, M.L.

1978-04-01

The Bandelier Tuff within the Pajarito Plateau consists of a lower sequence of air-fall and ash-flow deposits (Otowi Member) disconformably overlain by an upper sequence of air-fall and ash-flow deposits (Tshirege Member). The ash-flow sequence of the Tshirege Member consists of three cooling units throughout much of the Pajarito Plateau. The lower cooling unit is formed by three to as many as six pyroclastic flow units; the middle and upper cooling units each consist of at least three pyroclastic flow units. The contact between the lower and middle cooling unit coincides with a pyroclastic flow unit contact. This horizon is a prominent stratigraphic marker within distal sections of the Tshirege Member. Major and trace element analyses of unaltered and altered samples of the Bandelier Tuff were determined by neutron activation and delayed neutron activation and delayed neutron activation techniques. Petrographic, granulometric and morphologic characteristics of the Bandelier Tuff were determined to provide background information on the suitability of the Tuff as a medium for radioactive waste disposal. The hydrologic characteristics of the Bandelier Tuff are controlled primarily by secondary features of the Tuff (cooling zones). These features vary with emplacement temperature and transport distance of the Tuff. Primary depositional features provide second order control on transport pathways in distal sections of the Tuff

New sidescan sonar and gravity evidence that the Nova-Canton Trough is a fracture zone

Science.gov (United States)

Joseph, Devorah; Taylor, Brian; Shor, Alexander N.

1992-05-01

A 1990 sidescan sonar survey in the eastern region of the Nova-Canton Trough mapped 138°-striking abyssal-hill fabric trending into 70°-striking trough structures. The location and angle of intersection of the abyssal hills with the eastern Nova-Canton Trough effectively disprove a spreading-center origin of this feature. Free-air gravity anomalies derived from satellite altimetry data show continuity, across the Line Islands, of the Nova-Canton Trough with the Clipperton Fracture Zone. The Canton-Clipperton trend is copolar, about a pole at 30°S, 152°W, with other coeval Pacific-Farallon fracture-zone segments, from the Pau to Marquesas fracture zones. This copolarity leads us to postulate a Pacific-Farallon spreading pattern for the magnetic quiet zone region north and east of the Manihiki Plateau, with the Nova-Canton Trough originating as a transform fault in this system.

Active shortening, intermontane basin formation, and geomorphic evolution in an orogenic plateau: Central Puna Plateau, NW Argentina (24°37'S, 67°03'W)

Science.gov (United States)

Strecker, Manfred R.; Alonso, Ricardo N.; Bookhagen, Bodo; Freymark, Jessica; Pingel, Heiko

2017-04-01

The high-elevation Andean Plateau (Altiplano-Puna; 4km) is a first-order morphotectonic province of the Central Andes and constitutes the world's second largest orogenic plateau. While there are many unifying basin characteristics in this region, including internal drainage, semi-arid to arid climate and associated deposition of evaporites, there are notable differences between the northern and southern parts of the plateau. In contrast to the vast basins of the Altiplano (north) and incipient establishment of fluvial connectivity and sediment transport to the foreland, the Puna (south) comprises numerous smaller basins, bordered by reverse-fault bounded ranges up to 6 km high. The plateau is internally drained and fluvial connectivity with the foreland does not exist leading to thick sedimentary basin fills that comprise continental evaporites, volcanic and clastic deposits, typically between 3 and 5 km thick. However, repeated impacts of climate change and superposed tectonic activity in the southern plateau have resulted in further basin differentiation, abandonment or re-arrangement of fluvial networks and impacts on sediment transport. Here we report evidence for sustained contractional tectonic activity in the Pocitos Basin in the southern plateau. On the western margin of the basin fanning of dipping strata and regraded, steeply inclined gravel-covered pediment surfaces and wind gaps associated with gravel derived from distant sources in the west document late Tertiary to Pleistocene growth of an approximately N-S oriented and N plunging anticline. The growth of the eastern limb of this anticline has caused the isolation of a formerly more extensive basin. In addition, Late Pleistocene and Holocene lake shorelines and lacustrine deposits are tilted eastward along the same structure and InSAR measurements of deformed lake terraces document that the fold is growing. Despite widely reported extensional faulting in the southern Puna, we conclude (1) that the

Monuments of the Giza Plateau

Science.gov (United States)

Ruggles, Clive L. N.

The colossal pyramids of the pharaohs Khufu (Cheops), Khafre (Chephren), and Menkaure (Mycerinus) have attracted a huge amount of astronomical interest over the years, both scholarly and popular. Less attention is usually given to the broader context of structures on the Giza Plateau. One of the most notorious ideas connecting the Giza Plateau with astronomy is that the three large pyramids are laid out on the ground so as to reflect the appearance of the three stars of Orion's Belt in the sky. This idea is unsupportable for several reasons but has succeeded in generating huge public interest. Of much greater serious interest is the fact that the three main pyramids were oriented cardinally to extraordinary precision, which raises the questions of why this was important and how it was achieved. Another idea that has attracted serious attention but also some confusion is that the orientations of some narrow shafts within Khufu's pyramid might have been deliberately aligned upon particular stars. The overall layout of monuments on the plateau may certainly have been designed so as to emphasize certain solar phenomena, for symbolic and ideological reasons relating to a dominant sun cult. It is also possible that it formed part of a wider cosmological "master plan" extending to other pyramids and temples up to 20 km distant.

Pv rural electrification programme at the Bolivian high plateau

Energy Technology Data Exchange (ETDEWEB)

Lorenzo, E.; Aguilera, J. [Instituto de Energia Solar, ETSI Telecomunicacion, (Spain)

1995-12-31

Since 1988 the Institute of Solar Energy of the Universidad Politecnica de Madrid is carrying out a pv rural electrification programme at the Bolivian high plateau. This programme has been focused in three aspects: the domestic electrification, users participation and transfer technology. At present, there are about 1,500 electrified dwellings distributed in the Bolivian high plateau. We have got deep knowledge about life style and organization of the aymara Indians who are the inhabitants of the working zone. We think that this knowledge can be very useful for a large scale introduction of PV solar energy in this region. Finally, we present a new way to transfer PV technology to developing countries. Thanks to this programme a group of aymara Indians is able to manufacture charge regulators and electronic ballast to use in the PV installations of the programme. [Espanol] Desde 1988 el Instituto de Energia Solar de la Universidad Politecnica de Madrid esta llevando a cabo un programa fotovoltaico de electrificacion rural en la altiplanicie Boliviana. Este programa ha sido enfocado a tres aspectos: la electrificacion domestica, la participacion de los usuarios y la transferencia de la tecnologia. Actualmente, hay alrededor de 1500 conjuntos habitacionales electrificados distribuidos en la altiplanicie Boliviana. Hemos obtenido un profundo conocimiento del estilo de vida y de la organizacion de los indios aymara que son los habitantes de la zona de trabajo. Pensamos que este conocimiento puede ser muy util para una introduccion en gran escala de la energia solar fotovoltaica en esta region. Finalmente, presentamos una nueva forma de transferir la tecnologia fotovoltaica a paises en desarrollo. Gracias a este programa un grupo de indios aymara pueden fabricar reguladores de carga y balastros electronicos para ser usados en instalaciones fotovoltaicas del programa.

Pv rural electrification programme at the Bolivian high plateau

Energy Technology Data Exchange (ETDEWEB)

Lorenzo, E; Aguilera, J [Instituto de Energia Solar, ETSI Telecomunicacion, (Spain)

1996-12-31

Since 1988 the Institute of Solar Energy of the Universidad Politecnica de Madrid is carrying out a pv rural electrification programme at the Bolivian high plateau. This programme has been focused in three aspects: the domestic electrification, users participation and transfer technology. At present, there are about 1,500 electrified dwellings distributed in the Bolivian high plateau. We have got deep knowledge about life style and organization of the aymara Indians who are the inhabitants of the working zone. We think that this knowledge can be very useful for a large scale introduction of PV solar energy in this region. Finally, we present a new way to transfer PV technology to developing countries. Thanks to this programme a group of aymara Indians is able to manufacture charge regulators and electronic ballast to use in the PV installations of the programme. [Espanol] Desde 1988 el Instituto de Energia Solar de la Universidad Politecnica de Madrid esta llevando a cabo un programa fotovoltaico de electrificacion rural en la altiplanicie Boliviana. Este programa ha sido enfocado a tres aspectos: la electrificacion domestica, la participacion de los usuarios y la transferencia de la tecnologia. Actualmente, hay alrededor de 1500 conjuntos habitacionales electrificados distribuidos en la altiplanicie Boliviana. Hemos obtenido un profundo conocimiento del estilo de vida y de la organizacion de los indios aymara que son los habitantes de la zona de trabajo. Pensamos que este conocimiento puede ser muy util para una introduccion en gran escala de la energia solar fotovoltaica en esta region. Finalmente, presentamos una nueva forma de transferir la tecnologia fotovoltaica a paises en desarrollo. Gracias a este programa un grupo de indios aymara pueden fabricar reguladores de carga y balastros electronicos para ser usados en instalaciones fotovoltaicas del programa.

Plateau iris secondary to iridociliary cysts.

Science.gov (United States)

Vila-Arteaga, J; Díaz-Céspedes, R A; Suriano, M M

2015-11-01

We present a case of plateau iris and glaucoma due to multiple unilateral iridociliary cysts. The patient was treated with iridotomy Nd: YAG laser and 360° iridoplasty, without achieving pressure control. Phacoemulsification improved the hypertension. Dynamic gonioscopy and OCT of the anterior chamber was also performed before and after treatment. Iridociliary cysts are a benign condition that can cause iris plateau configuration, and can produce a difficult to treat ocular hypertension. Cystotomy, peripheral iridoplasty, and other treatments have been proposed. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Hexabromocyclododecane in alpine fish from the Tibetan Plateau, China

International Nuclear Information System (INIS)

Zhu, Nali; Fu, Jianjie; Gao, Yan; Ssebugere, Patrick; Wang, Yawei; Jiang, Guibin

2013-01-01

Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. The ∑HBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. α-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of ∑HBCDs in the fish were significantly correlated with the lipid content . A decreasing trend was observed between α-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau. -- Highlights: •HBCDs were ubiquitous in fish of the Tibetan Plateau. •α-HBCD showed a negative correlation with TL in the Lhasa River aquatic food web. •Concentrations of ∑HBCD were significantly correlated with lipid contents of fish. -- HBCD was ubiquitous in fish of the Tibetan Plateau, and its concentration was significantly correlated with lipid content

Distribution and migration of aftershocks of the 2010 Mw 7.4 Ogasawara Islands intraplate normal-faulting earthquake related to a fracture zone in the Pacific plate

Science.gov (United States)

Obana, Koichiro; Takahashi, Tsutomu; No, Tetsuo; Kaiho, Yuka; Kodaira, Shuichi; Yamashita, Mikiya; Sato, Takeshi; Nakamura, Takeshi

2014-04-01

describe the aftershocks of a Mw 7.4 intraplate normal-faulting earthquake that occurred 150 km east Ogasawara (Bonin) Islands, Japan, on 21 December 2010. It occurred beneath the outer trench slope of the Izu-Ogasawara trench, where the Pacific plate subducts beneath the Philippine Sea plate. Aftershock observations using ocean bottom seismographs (OBSs) began soon after the earthquake and multichannel seismic reflection surveys were conducted across the aftershock area. Aftershocks were distributed in a NW-SE belt 140 km long, oblique to the N-S trench axis. They formed three subparallel lineations along a fracture zone in the Pacific plate. The OBS observations combined with data from stations on Chichi-jima and Haha-jima Islands revealed a migration of the aftershock activity. The first hour, which likely outlines the main shock rupture, was limited to an 80 km long area in the central part of the subsequent aftershock area. The first hour activity occurred mainly around, and appears to have been influenced by, nearby large seamounts and oceanic plateau, such as the Ogasawara Plateau and the Uyeda Ridge. Over the following days, the aftershocks expanded beyond or into these seamounts and plateau. The aftershock distribution and migration suggest that crustal heterogeneities related to a fracture zone and large seamounts and oceanic plateau in the incoming Pacific plate affected the rupture of the main shock. Such preexisting structures may influence intraplate normal-faulting earthquakes in other regions of plate flexure prior to subduction.

The dating and interpretation of Chusang indicates permanent human occupation of the interior of the Tibetan Plateau in the early Holocene

Science.gov (United States)

Meyer, Michael; Aldenderfer, Mark; Wang, Zhijun; Hoffmann, Dirk; Dahl, Jenny; Degering, Detlev; Haas, Randy; Schlütz, Frank; Gliganic, Luke; May, Jan-Hendrik

2017-04-01

The nature and timing of a permanent human settlement on the Tibetan Plateau and the accompanying cultural and physiological responses, including genetic high-altitude adaptations, are subject to ongoing debate (1-3). The latest genetic data (based on extensive analysis of the modern Tibetan genome) suggest a main wave of human migration onto the plateau between 15 and 8 ka but genetic traces that hint to an even earlier initial occupation (dating to 65 ka) have to be considered too (4, 5). The archaeological record against which these genetic data can be compared to remains scant. The few archaeological sites with a chronometric age are all located on the northeastern margin of the plateau and range in date from 9 to 15 ka. These sites typically are at medium to low elevations (≤ 3300 masl) and are believed to have been short-term, seasonal occupations monitored from lower-elevation base camps (1). It is widely believed that permanent peopling of the interior (higher-elevation zones) of the Tibetan Plateau was only facilitated by an agricultural lifeway at 3.6 thousand calibrated carbon-14 years before present (2). The climatic and paleoenvironmental constraints on this colonization process are poorly understood (1-3). Here we report a reanalysis of the chronology and paleoenvironmental significance of the Chusang site, located on the central Tibetan Plateau at an elevation of 4270 meters above sea level (3). The site is known for its hot springs and extensive hydrothermal carbonate (travertine) formations and also preserves 19 human hand- and footprints on the surface of a fossil travertine sheet. The minimum age of the site is fixed at 7.4 thousand years (thorium-230/uranium dating), with a maximum age between 8.20 and 12.67 thousand calibrated carbon-14 years before present based on radiocarbon and OSL single-grain dating. Travel cost modeling and archaeological data suggest that the site was part of an annual, permanent, preagricultural occupation of the

Greenhouse gases emissions in rivers of the Tibetan Plateau.

Science.gov (United States)

Qu, Bin; Aho, Kelly Sue; Li, Chaoliu; Kang, Shichang; Sillanpää, Mika; Yan, Fangping; Raymond, Peter A

2017-11-29

Greenhouse gases (GHGs) emissions from streams are important to regional biogeochemical budgets. This study is one of the first to incorporate stream GHGs (CO 2 , CH 4 and N 2 O) concentrations and emissions in rivers of the Tibetan Plateau. With one-time sampling from 32 sites in rivers of the plateau, we found that most of the rivers were supersaturated with CO 2 , CH 4 and N 2 O during the study period. Medians of partial pressures of CO 2 (pCO 2 ), pCH 4 and pN 2 O were presented 864 μatm, 6.3 μatm, and 0.25 μatm respectively. Based on a scaling model of the flux of gas, the calculated fluxes of CO 2 , CH 4 and N 2 O (3,452 mg-C m 2 d -1 , 26.7 mg-C m 2 d -1 and 0.18 mg-N m 2 d -1 , respectively) in rivers of the Tibetan Plateau were found comparable with most other rivers in the world; and it was revealed that the evasion rates of CO 2 and CH 4 in tributaries of the rivers of the plateau were higher than those in the mainstream despite its high altitude. Furthermore, concentrations of GHGs in the studied rivers were related to dissolved carbon and nitrogen, indicating that riverine dissolved components could be used to scale GHGs envision in rivers of the Tibetan Plateau.

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

OpenAIRE

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

2017-01-01

AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fract...

Plateau iris Íris em platô

Directory of Open Access Journals (Sweden)

Alberto Diniz Filho

2008-10-01

Full Text Available The term plateau iris was first coined in 1958 to describe the iris configuration of a patient. Two years later the concept of plateau iris was published. In 1977, the plateau iris configuration was classically defined as presurgical changes of an eye with a relative normal central anterior chamber depth, flat iris by conventional biomicroscopy, but displaying an extremely narrow or closed angle on gonioscopic examination. On the other hand, the plateau iris syndrome was defined as an acute glaucoma crisis in one eye with a relative normal central anterior chamber depth and patent iridotomy on direct examination, presenting angle closure confirmed by gonioscopic examination after mydriasis. In 1992, the anatomic aspects of plateau iris were studied using ultrasound biomicroscopy. Finally, plateau iris has been considered an anatomic variant of iris structure in which the iris periphery angulates sharply forward from its insertion point and then again angulates sharply and centrally backward, along with an anterior positioning of the ciliary processes seen on ultrasound biomicroscopy. The clinical treatment of plateau iris syndrome is carried out with topical use of pilocarpine. However, the definitive treatment should be fulfilled by performing an argon laser peripheral iridoplasty.O termo íris em platô foi primeiramente inventado em 1958 para descrever a configuração da íris de um paciente. Dois anos depois o conceito de íris em platô foi publicado. Em 1977, a configuração de íris em platô foi classicamente definida como alterações pré-cirúrgicas de um olho com uma profundidade de câmara anterior relativamente normal, íris plana pela biomicroscopia convencional, mas mostrando um ângulo extremamente estreito ou fechado pela gonioscopia. Por outro lado, a síndrome de íris em platô foi definida como uma crise de glaucoma agudo em um olho com uma profundidade de câmara anterior relativamente normal e uma iridectomia patente ao

A geophysical cross-section of the Hockai Fault Zone (Eastern Belgium): imaging an intraplate weak crustal zone.

Science.gov (United States)

Lecocq, T.; Camelbeeck, T.

2016-12-01

The Hockai Fault Zone (HFZ) is a NNW-SSE trending structure visible in the regional geomorphology in the Ardennes, Eastern-Belgium. It is situated, between the Pays de Herve (Graben de la Minerie) to the North and the Amblève river, to the South. It crosses the Stavelot Massif, almost perpendicular to the Crête de la Vecquée (Vecquée crest), i.e. the highest crest of the Venn. Faults have been identified or suspected on a contour map of the base of the Tertiary cover (Eocene or Oligocene) in the north western and central Rhenish Massif. These faults are necessary to account for the altitude difference of the base of the cover. The deflection or capture of local rivers show a remarkable alignments on more than 42 km N-S. The alignments are mostly trending SSE-NNW, between N140 and N170, with some potential segments with slightly different orientations. This general orientation has been also evidenced from the analyses of Landsat-1 imagery products. At its crossing with the Vecquée Crest, Demoulin locates the HFZ where the Hoëgne river turns sharply towards the north and crosscuts the quarzitic crest. Demoulin identifies three subparallel faults or fault zones on the Hautes-Fagnes plateau, from East to West: the Eupen faulting zone, the Baelen faulting zone and Hockai faulted zone. In this communication, we report on a large-scale geophysical survey that was conducted in order to search of the Hockai fault zone expression at the surface. The locations to search for the Hockai Fault Zone are based on the surface projection of the 1989/1990 seismic swarm that occurred under the Stavelot Massif, geomorphological evidences and past geophysical surveys in the region. Our objective is not to prove a Quaternary movement of faults, but rather to find reliable evidences of their presence and to analyse their lateral extension. In total, 31 ERT profiles were executed almost parallel to the Vecquée Crest, i.e. a total of 10679 meters of profiles. Four zones are imaged

Oxygen-18 in present-day precipitation on the Tibetan Plateau

Institute of Scientific and Technical Information of China (English)

章新平; 姚檀栋; 中尾正义

2001-01-01

The temporal and spatial variations of the δ18O in precipitation on the Tibetan Plateau are analyzed. There is no temperature effect in the southern Tibetan Plateau. Amount effect has been observed at Lhasa station. However, the seasonal variations of the δ18O in precipitation are different from that of precipitation intensity, showing that the precipitation intensity is not a main controlling factor on the stable isotopic compositions in precipitation in the southern Tibetan Plateau. There is notable temperature effect in the middle and northern Tibetan Plateau. The seasonal variations of the δ18O in precipitation are almost consistent with those of air temperature there, indicating that temperature is a main factor controlling the stable isotopic variations in precipitation. A meridional cross-section shows that a notable depletion of the stable isotopic ratio in precipitation takes place in the Himalayas due to very strong rainout of vapor as it rises over the Himalayas, then the δ18O remains basi

New Data on the Composition of Cretaceous Volcanic Rocks of the Alazeya Plateau, Northeastern Yakutia

Science.gov (United States)

Tsukanov, N. V.; Skolotnev, S. G.

2018-02-01

This work presents new data on the composition of volcanics, developed within the Alazeya Plateau of the Kolyma-Indigirka fold area (Northeast Russia), which indicate essential differences in their composition and, accordingly, different geodynamic settings of the formation of rocks. The studied igneous rocks are subdivided into two groups. Volcanics of the first group of the Late Cretaceous age, which are represented by differentiated volcanic rock series (from andesitobasalts to dacites and rhyolites), were formed under island arc conditions in the continent-ocean transition zone. Volcanics of the second group are ascribed to the tholeiitic series and were formed under the other geodynamic setting, which is associated with the regime of extension and riftogenesis, manifested in the studied area probably at the later stage.

Behavior of Colorado Plateau uranium minerals during oxidation

Science.gov (United States)

Garrels, Robert Minard; Christ, C.L.

1956-01-01

Uranium occurs as U(VI) and U(IV) in minerals of the Colorado Plateau ores. The number of species containing U(VI) is large, but only two U(IV) minerals are known from the Plateau: uraninite, and oxide, and coffinite, a hydroxy-silicate. These oxidize to yield U(VI) before reacting significantly with other mineral constituents. Crystal-structure analysis has shown that U(VI) invariable occurs as uranyl ion, UO2+2. Uranyl ion may form complex carbonate or sulfate ions with resulting soluble compounds, but only in the absence of quinquevalent vanadium, arsenic, or phosphorous. In the presence of these elements in the +5 valence state, the uranyl ion is fixed in insoluble layer compounds formed by union of uranyl ion with orthovanadate, orthophosphate, or orthoarsenate. Under favorable conditions UO2+2 may react to form the relatively insoluble rutherfordine, UO2CO3, or hydrated uranyl hydroxides. These are rarely found on the Colorado Plateau as opposed to their excellent development in other uraniferous areas, a condition which is apparently related to the semiarid climate and low water table of the Plateau. Uranium may also be fixed as uranyl silicate, but little is known about minerals of this kind. In the present study emphasis has been placed on a detailing of the chemical and crystal structural changes which occur in the oxidation paragenetic sequence.

Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

Directory of Open Access Journals (Sweden)

Yadong Wang

2012-03-01

Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

The Caribbean-Colombian cretaceous igneous province: The internal anatomy of an oceanic plateau

Science.gov (United States)

Kerr, Andrew C.; Tarney, John; Marriner, Giselle F.; Nivia, Alvaro; Saunders, Andrew D.

The Late Cretaceous Caribbean—Colombian igneous province is one of the world's best-exposed examples of a plume-derived oceanic plateau. The buoyancy of the plateau (resulting from residual heat and thick crust) kept it from being totally subducted as it moved eastward with the Farallon Plate from its site of generation in the eastern Pacific and encountered a destructive plate margin. In effect, the plateau makes up much of the Caribbean Plate; it is well exposed around its margins, but more so in accreted terranes in western Colombia (including the well-known Gorgona komatiites and Bolívar mafic/ultramafic cumulates). Compositionally, the lavas of the plateau form three groups: (a) basalts, picrites, and komatiites with light-rare-earth-element (LREE)-depleted chondrite-normalised patterns; (b) basalts with LREE-enriched patterns; and (c) basalts with essentially flat REE patterns (the most dominant type) similar to many of the basalts from the Ontong Java Plateau. These three types demonstrate the heterogeneous nature of the mantle plume source region. The picrites and the komatiites seem to lie nearer the base of the plateau than the more homogeneous basalts; thus, the more MgO-rich melts may have been erupted before large magma chambers had a chance to develop. A reconstructed crustal cross section through the plateau consists of dunitic and pyroxenitic cumulates near the base which are overlain by layered olivine-rich gabbros and more isotropic gabbros. The lowermost eruptive sequence comprises compositionally heterogeneous picrites/komatiites overlain by more homogeneous pillow basalts. Spectacular hornblende-plagioclase veins cut the Bolívar assemblage and these may represent local partial melts of the plateau's base as it was thrusted onto the continent. Subduction-related batholiths and extrusive rocks found around the margin of the province are of two distinct ages; one suite represents pre-plateau collision-related volcanism whereas the other suite

[Correlation between morphogical factor of lateral plateau fracture and meniscus injury].

Science.gov (United States)

Bai, L; Zhou, W; Zhang, W T; Huang, W; You, T; Chen, P; Zhang, H L

2016-04-18

To analyze morphological character of lateral tibial plateau fracture fragment, and its correlation to the presence of a meniscus injury in tibial plateau fractures. A total of 79 consecutive patients of the simple lateral tibial plateau fractures from July 2011 to July 2015 were included in this study, with 65 males and 14 females with an average age of (34.3±7.2) years and 22-61 years. According to Schatzker classification, 21 cases were of Type I, 41 cases Type II, and 17 cases Type III. The characteristics of lateral tibial plateau fractures were evaluated by plain X-ray and magnetic resonance imaging (MRI). The type and severity of meniscus injury were diagnosed by MRI scan. Three-dimensional measurements of the lateral fragment width (LFW), the lateral plateau depression (LPD), the coronal angulation of lateral fragment (CALF), and tibial plateau widening (TPW) were measured with Picture Archiving and Communication Systems(PACS) software. The patients with and without meniscus injuries were divided into different groups and analyzed respectively. Comparison of the above measurements between the two groups was analyzed by independent t test. In all the 79 lateral tibial plateau fracture patients, 26 cases (32.9%) of meniscus injuries were detected by MRI. Among all the meniscus injury cases, 3 were of Schatzker I, 16 Schatzker II, and 7 Schatzker III. In meniscus intact group, the average LFW was (22.0±2.8) mm while in meniscus injury group it was (21.3± 3.3) mm (t=-1.008, P=0.317).The average LPD of non meniscus injury group was (5.4±2.8) mm, while in meniscus injury group was (8.7±2.8) mm (t=4.98, P=0.001). The average CALF of the two groups were 9.1°±6.1°and 10.6°± 7.1°, and there was no significant difference between the two groups (t=0.38, P=0.831). The average TPW was (3.0± 1.1) mm, and (4.8±1.7) mm of the two groups. There were significant differences between the two groups (t=5.216, P=0.001). There was no obvious correlation between the

Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

Energy Technology Data Exchange (ETDEWEB)

Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

2015-09-16

We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

Organizational restructuring and career plateauing

NARCIS (Netherlands)

P. Paffen; Hans Timmermans

2009-01-01

This article describes a flexibility program for plateaued professionals in a technical Dutch firm operating in the consultancy sector we will refer to with the pseudonym Greentree Corp. First, we will discuss the impact reorganization had on job-requirements and career opportunities for technical

Black Carbon Radiative Forcing over the Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

He, Cenlin; Li, Qinbin; Liou, K. N.; Takano, Y.; Gu, Yu; Qi, L.; Mao, Yuhao; Leung, Lai-Yung R.

2014-11-28

We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. Our best estimate of the annual BC snow albedo forcing in the Plateau is 2.9 W m-2 (uncertainty: 1.5–5.0 W m-226 ). We find that BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing and coated BC increases the forcing by 30-50% compared with uncoated BC, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. Our best estimate of the annual BC DRF at the top of the atmosphere is 2.3 W m-2 (uncertainty: 0.7–4.3 W m-230 ) in the Plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network (AERONET) observations. The BC forcings are attributed to emissions from different regions.

Antibacterial Activity of Ethanolic Extract of Acalypha wilkesiana Leaves Growing in Jos, Plateau State, Nigeria

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Gotep, J. G.

2010-01-01

Full Text Available Antibacterial activity of ethanolic extract of Acalypha wilkesiana leaves growing in Vom, Jos, Plateau state, Nigeria was carried out to verify claims by the locals of its medicinal properties. We tested the extract for activity against Staphylococcus aureus (G+, Yersinia enterocolitica, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Klebsiella aerogenes (G-. The extract exhibited activity against the organisms in varying degrees. In the agar diffusion test, Y. enterocolitica showed the highest zone of inhibition (18 mm at the highest concentration of extract tested (20 mg/mL while E. coli, S. aureus, S. typhi, P. aeruginosa and K. aerogenes showed zones of inhibition of 17, 16, 15, 14 and 16 mm respectively. At extract concentration of 2.5 mg/mL, Y. enterocolitica and P. aeruginosa did not show any zones of inhibition while E.coli, S. aureus, S. typhi, and K. aerogenes showed zones of inhibition of 7, 6, 6 and 7 mm respectively. Below extract concentration of 2.5 mg/mL, there was no zone of inhibition observed with any organism. The MIC of the extract against the organisms was 5 mg/mL except on S. aureus where the MIC was 2.5 mg/mL. The MBC of the extract was 10 mg/mL against Y. enterocolitica, S. typhi, P. aeruginosa and K. aerogenes, 5 mg/mL against E. coli and S. aureus. Preliminary phytochemical testing revealed the presence of tannins, steroids, flavonoids and cardiac glycosides while saponins, alkaloids and anthraquinones were not present. The result gives scientific backing to the use of the leaves by the local people in the treatment of conditions usually associated with the organisms tested.

Plateau inflation in R-parity violating MSSM

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Girish Kumar Chakravarty

2016-12-01

Full Text Available Inflation with plateau potentials give the best fit to the CMB observables as they predict tensor to scalar ratio stringently bounded by the observations from Planck and BICEP2/Keck. In supergravity models it is possible to obtain plateau potentials for scalar fields in the Einstein frame which can serve as the inflation potential by considering higher dimensional Planck suppressed operators and by the choice of non-canonical Kähler potentials. We construct a plateau inflation model in MSSM where the inflation occurs along a sneutrino-Higgs flat direction. A hidden sector Polonyi field is used for the breaking of supersymmetry after the end of the inflation. The proper choice of superpotential leads to strong stabilization of the Polonyi field, mZ2≫m3/22, which is required to solve the cosmological moduli problem. Also, the SUSY breaking results in a TeV scale gravitino mass and scalar masses and gives rise to bilinear and trilinear couplings of scalars which can be tested at the LHC. The sneutrino inflation field can be observed at the LHC as a TeV scale diphoton resonance like the one reported by CMS and ATLAS.

Posterior Slope of the Tibia Plateau in Malaysian Patients Undergoing Total Knee Replacement

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R Yoga

2009-05-01

Full Text Available The posterior slope of the tibial plateau is an important feature to preserve during knee replacement. The correct slope aids in the amount of flexion and determines if the knee will be loose on flexion. This is a study on the posterior tibial plateau slope based on preoperative and postoperative radiographs of 100 consecutive patients who had total knee replacements. The average posterior slope of the tibia plateau was 10.1 degrees. There is a tendency for patients with higher pre-operative posterior tibial plateau slope to have higher post-operative posterior tibial plate slope.

Fish Lake, Utah - a promising long core site straddling the Great Basin to Colorado Plateau transition zone

Science.gov (United States)

Marchetti, D. W.; Abbott, M. B.; Bailey, C.; Wenrich, E.; Stoner, J. S.; Larsen, D. J.; Finkenbinder, M. S.; Anderson, L.; Brunelle, A.; Carter, V.; Power, M. J.; Hatfield, R. G.; Reilly, B.; Harris, M. S.; Grimm, E. C.; Donovan, J.

2015-12-01

Fish Lake (~7x1.5 km and 2696 m asl) is located on the Fish Lake Plateau in central Utah. The Lake occupies a NE-striking tectonic graben; one of a suite of grabens on the Plateau that cut 21-26 Ma volcanic rocks. The lake outflows via Lake Creek to the NE where it joins Sevenmile Creek to become the Fremont River, a tributary to the Colorado River. A bathymetric survey reveals a mean depth of 27 m and a max depth of 37.2 m. The lake bottom slopes from NW to SE with the deepest part near the SE wall, matching the topographic expression of the graben. Nearby Fish Lake Hightop (3545 m) was glaciated with an ice field and outlet glaciers. Exposure ages indicate moraine deposition during Pinedale (15-23 ka) and Bull Lake (130-150 ka) times. One outlet glacier at Pelican Canyon deposited moraines and outwash into the lake but the main basin of the lake was never glaciated. Gravity measurements indicate that lake sediments thicken toward the SE side of the lake and the thickest sediment package is modeled to be between 210 and 240 m. In Feb 2014 we collected cores from Fish Lake using a 9-cm diameter UWITECH coring system in 30.5 m of water. A composite 11.2-m-long core was constructed from overlapping 2 m drives that were taken in triplicate to ensure total recovery and good preservation. Twelve 14C ages and 3 tephra layers of known age define the age model. The oldest 14C age of 32.3±4.2 cal ka BP was taken from 10.6 m. Core lithology, CT scans, and magnetic susceptibility (ms) reveal three sediment packages: an organic-rich, low ms Holocene to post-glacial section, a fine-grained, minerogenic glacial section with high ms, and a short section of inferred pre-LGM sediment with intermediate composition. Extrapolating the age model to the maximum estimated sediment thicknesses suggest sediments may be older than 500-700 ka. Thus Fish Lake is an ideal candidate for long core retrieval as it likely contains paleoclimatic records extending over multiple glacial cycles.

[The epidemiology and etiology research of Tibetan sheep plague in Qinghai plateau].

Science.gov (United States)

Wei, Baiqing; Xiong, Haoming; Yang, Xiaoyan; Yang, Yonghai; Qi, Meiying; Jin, Juan; Xin, Youquan; Li, Xiang; Yang, Hanqing; Han, Xiumin; Dai, Ruixia

2015-03-01

To identify the epidemiology and etiology characteristics of Tibetan sheep plague in Qinghai plateau. The background materials of Qinghai Tibetan sheep plague found during 1975 to 2009 were summarized, the regional, time and interpersonal distribution, infection routes, ecological factors for the spread were used to analyze; followed by choosing 14 Yersinia pestis strains isolated from such sheep for biochemical test, toxicity test, virulence factors identification, plasmid analysis, and DFR genotype. From 1975 to 2009, 14 Yersinia pestis strains were isolated from Tibetan sheep in Qinghai province. Tibetan sheep, as the infection source, had caused 10 cases of human plague, 25 plague patients, and 13 cases of death. All of the initial cases were infected due to eating Tibetan sheep died of plague; followed by cases due to contact of plague patients, while all the initial cases were bubonic plague. Cases of bubonic plague developed into secondary pneumonic plague and septicemia plague were most popular and with high mortality. Most of the Tibetan sheep plague and human plague occurred in Gannan ecological zone in southern Gansu province, which was closely related to its unique ecological and geographical landscape. Tibetan sheep plague coincided with human plague caused by Tibetan sheep, especially noteworthy was that November (a time for marmots to start their dormancy) witnesses the number of Yersinia pestis strains isolated from Tibetan sheep and human plague cases caused by Tibetan sheep. This constituted the underlying cause that the epidemic time of Tibetan sheep plague lags obviously behind that of the Marmot plague. It was confirmed in the study that all the 14 strains were of Qinghai-Tibet Plateau ecotype, with virulence factors evaluation and toxicity test demonstrating strains as velogenic. As found in the (Different Region) DFR genotyping, the strains isolated from Yushu county and Zhiduo county were genomovar 5, the two strain isolated from Nangqian

Spiny Neurons of Amygdala, Striatum and Cortex Use Dendritic Plateau Potentials to Detect Network UP States

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Katerina D Oikonomou

2014-09-01

Full Text Available Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: [1] they are the most abundant cell type within their respective brain area, [2] covered by thousands of thorny protrusions (dendritic spines, [3] possess high levels of dendritic NMDA conductances, and [4] experience sustained somatic depolarizations in vivo and in vitro (UP states. In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (dendritic UP states characterized by (i fast rise, (ii plateau phase lasting several hundred milliseconds and (iii abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates towards the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200 – 800 ms steady depolarization (~20 mV amplitude, which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states. We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states.

Excessive Afforestation and Soil Drying on China's Loess Plateau

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Zhang, Shuilei; Yang, Dawen; Yang, Yuting; Piao, Shilong; Yang, Hanbo; Lei, Huimin; Fu, Bojie

2018-03-01

Afforestation and deforestation as human disturbances to vegetation have profound impacts on ecohydrological processes influencing both water and carbon cycles and ecosystem sustainability. Since 1999, large-scale revegetation activities such as "Grain-to-Green Program" have been implemented across China's Loess Plateau. However, negative ecohydrological consequences, including streamflow decline and soil drying have emerged. Here we estimate the equilibrium vegetation cover over the Loess Plateau based on an ecohydrological model and assess the water balance under the equilibrium and actual vegetation cover over the past decade. Results show that the current vegetation cover (0.48 on average) has already exceeded the climate-defined equilibrium vegetation cover (0.43 on average) in many parts of the Loess Plateau, especially in the middle-to-east regions. This indicates a widespread overplanting, which is found to primarily responsible for soil drying in the area. Additionally, both the equilibrium vegetation cover and soil moisture tend to decrease under future (i.e., 2011-2050) climate scenarios due to declined atmospheric water supply (i.e., precipitation) and increased atmospheric water demand (i.e., potential evapotranspiration). Our findings suggest that further revegetation on the Loess Plateau should be applied with caution. To maintain a sustainable ecohydrological environment in the region, a revegetation threshold is urgently needed to guide future revegetation activities.

Potential of para-boronophenylalaninol as a boron carrier in boron neutron capture therapy, referring to that of its enantiomers

International Nuclear Information System (INIS)

Masunaga, S.; Sakurai, Y.; Ono, K.; Suziki, M.; Nagata, K.; Takagaki, M.; Nagasawa, H.

2003-01-01

We evaluated the potential of a newly developed 10 B-containing alpha-amino alcohol of para-boronophenylalanine- 10 B (BPA), para-boronophenylalaninol (BPAol), as a boron carrier in boron neutron capture therapy. C57BL mice bearing EL4 tumors and C3H/He mice bearing SCC VII tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously via implanted mini-osmotic pumps to label all proliferating (P) cells. After oral administration of L-BPA or D-BPA, or intraperitoneal injection of L-BPAol or D-BPAol, the tumors were irradiated with reactor thermal neutron beams. For the combination with mild temperature hyperthermia (MTH) and/or tirapazamine (TPZ), the tumors were heated at 40 degrees centigrade for 30 minutes right before neutron exposure, and/or TPZ was intraperitoneally injected 30 minutes before irradiation. The tumors were then excised, minced and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling ( = quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. Meanwhile, 6 hours after irradiation, tumor cell suspensions obtained in the same manner were used for determining the apoptosis frequency in Q cells. The apoptosis and MN frequency in total (P + Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Without TPZ or MTH, L- and D-BPAol increased both frequencies markedly, especially for total cells. Although not significantly, L-BPA and D-BPAol increased both frequencies slightly more remarkably than D-BPA and L-BPAol, respectively. On combined treatment with both MTH and TPZ, the sensitivity difference between total and Q cells was markedly reduced. MTH increased the 10 B uptake of all 10 B-carriers into both tumor cells to some degree. Both L- and D-BPAol have potential as 10 B-carriers in neutron capture therapy, especially when combined with both MTH and TPZ

Aged dissolved organic carbon exported from rivers of the Tibetan Plateau.

Science.gov (United States)

Qu, Bin; Sillanpää, Mika; Li, Chaoliu; Kang, Shichang; Stubbins, Aron; Yan, Fangping; Aho, Kelly Sue; Zhou, Feng; Raymond, Peter A

2017-01-01

The role played by river networks in regional and global carbon cycle is receiving increasing attention. Despite the potential of radiocarbon measurements (14C) to elucidate sources and cycling of different riverine carbon pools, there remain large regions such as the climate-sensitive Tibetan Plateau for which no data are available. Here we provide new 14C data on dissolved organic carbon (DOC) from three large Asian rivers (the Yellow, Yangtze and Yarlung Tsangpo Rivers) running on the Tibetan Plateau and present the carbon transportation pattern in rivers of the plateau versus other river system in the world. Despite higher discharge rates during the high flow season, the DOC yield of Tibetan Plateau rivers (0.41 gC m-2 yr-1) was lower than most other rivers due to lower concentrations. Radiocarbon ages of the DOC were older/more depleted (511±294 years before present, yr BP) in the Tibetan rivers than those in Arctic and tropical rivers. A positive correlation between radiocarbon age and permafrost watershed coverage was observed, indicating that 14C-deplted/old carbon is exported from permafrost regions of the Tibetan Plateau during periods of high flow. This is in sharp contrast to permafrost regions of the Arctic which export 14C-enriched carbon during high discharge periods.

Soil moisture decline due to afforestation across the Loess Plateau, China

Science.gov (United States)

Jia, Xiaoxu; Shao, Ming'an; Zhu, Yuanjun; Luo, Yi

2017-03-01

The Loess Plateau of China is a region with one of the most severe cases of soil erosion in the world. Since the 1950s, there has been afforestation measure to control soil erosion and improve ecosystem services on the plateau. However, the introduction of exotic tree species (e.g., R. pseudoacacia, P. tabulaeformis and C. korshinskii) and high-density planting has had a negative effect on soil moisture content (SMC) in the region. Any decrease in SMC could worsen soil water shortage in both the top and deep soil layers, further endangering the sustainability of the fragile ecosystem. This study analyzed the variations in SMC following the conversion of croplands into forests in the Loess Plateau. SMC data within the 5-m soil profile were collected at 50 sites in the plateau region via field survey, long-term in-situ observations and documented literature. The study showed that for the 50 sites, the depth-averaged SMC was much lower under forest than under cropland. Based on in-situ measurements of SMC in agricultural plots and C. korshinskii plots in 2004-2014, SMC in the 0-4 m soil profile in both plots declined significantly (p resources demands in the Loess Plateau.

Response of surface springs to longwall coal mining Wasatch Plateau, Utah

International Nuclear Information System (INIS)

Kadnuck, L.L.M.

1994-01-01

High-extraction longwall coal mining creates zones in the overburden where strata bend, fracture, or cave into the mine void. These physical alterations to the overburden stratigraphy have associated effects on the hydrologic regime. The US Bureau of Mines (SBM) studied impacts to the local hydrologic system caused by longwall mining in the Wasatch Plateau, Utah. Surface springs in the vicinity of two coal mines were evaluated for alterations in flow characteristics as mining progressed. Fourteen springs located above the mines were included in the study. Eight of the springs were located over longwall panels, four were located over barrier pillars and mains, and two ere located outside the area disturbed by mining. Flow hydrographs for each spring were compared to climatic data and time of undermining to assess if mining in the vicinity had influenced flow. Heights of fracturing and caving in the overburden resulting from seam extraction were calculated using common subsidence formulas, and used in conjunction with elevations of springs to assess if fracturing influenced the water-bearing zones studied. One spring over a panel exhibited a departure from a normally-shaped hydrograph after being undermined. Springs located over other mine structures, or outside the mine area did not show discernible effects from mining. The limited response of the springs was attributed to site-specific conditions that buffered mining impacts including the elevation of the springs above the mine level, and presence of massive sandstones and swelling clays in the overburden materials

Evaporation from bare ground with different water-table depths based on an in-situ experiment in Ordos Plateau, China

Science.gov (United States)

Zhang, Zaiyong; Wang, Wenke; Wang, Zhoufeng; Chen, Li; Gong, Chengcheng

2018-03-01

The dynamic processes of ground evaporation are complex and are related to a multitude of factors such as meteorological influences, water-table depth, and materials in the unsaturated zone. To investigate ground evaporation from a homogeneous unsaturated zone, an in-situ experiment was conducted in Ordos Plateau of China. Two water-table depths were chosen to explore the water movement in the unsaturated zone and ground evaporation. Based on the experimental and calculated results, it was revealed that (1) bare ground evaporation is an atmospheric-limited stage for the case of water-table depth being close to the capillary height; (2) the bare ground evaporation is a water-storage-limited stage for the case of water-table depth being beyond the capillary height; (3) groundwater has little effect on ground-surface evaporation when the water depth is larger than the capillary height; and (4) ground evaporation is greater at nighttime than that during the daytime; and (5) a liquid-vapor interaction zone at nearly 20 cm depth is found, in which there exists a downward vapor flux on sunny days, leading to an increasing trend of soil moisture between 09:00 to 17:00; the maximum value is reached at midday. The results of this investigation are useful to further understand the dynamic processes of ground evaporation in arid areas.

Early Human Occupation on the Northeast Tibetan Plateau

Science.gov (United States)

Rhode, D.; Madsen, D.; Brantingham, P.; Perrault, C.

2010-12-01

The Tibetan Plateau presents great challenges for human occupation: low oxygen, high ultraviolet radiation, harsh seasonal climate, low overall biological productivity. How and when early humans were able to cope physiologically, genetically, and behaviorally with these extremes is important for understanding the history of human adaptive flexibility. Our investigations of prehistoric human settlement on the northeast Tibetan Plateau focus on (a) establishing well-dated evidence for occupation of altitudes >3000 m, (b) the environmental context of high altitude adaptation, and (c) relations of hunting and pastoralism to lower-altitude agrarian systems. We observe two major prehistoric settlement patterns in the Qinghai Lake area. The earliest, ~15,000-7500 yr old, consists of small isolated firehearths with sparse associated stone tools and wild mammal remains (1). Numerous hearths often occur in the same localities, indicating repeated short-duration occupations by small hunting parties. A second pattern, ~9000-4000 yr old, was established during the Holocene climatic optimum. These sites represent prolonged seasonal residential occupation, containing dark anthropogenic midden, hearth and pit constructions, abundant stone tools, occasional ceramics, and abundant diverse faunal remains (including medium-large mammals but lacking domestic sheep/yak)(2). These Plateau-margin base camps allowed greater intensity of use of the high Plateau. Residential occupation was strongly influenced by nearby lower-altitude farming communities; development of the socioeconomic landscape along the Yellow River likely played at least as great a role in Plateau occupation patterns as did Holocene environmental changes. Holocene vegetation changes in the NE Tibetan Plateau have been attributed to climate (3) or anthropogenic modification (4). Our results document changes in shrub/tree presence from ~12,000-4000 BP, similar to pollen records, that likely reflect climate rather than

Mineralogy and geochemistry of vanadium in the Colorado Plateau

Science.gov (United States)

Weeks, A.D.

1961-01-01

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

Science.gov (United States)

Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

2015-01-01

The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

[Surgical approaches to tibial plateau fractures].

Science.gov (United States)

Krause, Matthias; Müller, Gunnar; Frosch, Karl-Heinz

2018-06-06

Intra-articular tibial plateau fractures can present a surgical challenge due to complex injury patterns and compromised soft tissue. The treatment goal is to spare the soft tissue and an anatomical reconstruction of the tibial articular surface. Depending on the course of the fracture, a fracture-specific access strategy is recommended to provide correct positioning of the plate osteosynthesis. While the anterolateral approach is used in the majority of lateral tibial plateau fractures, only one third of the joint surface is visible; however, posterolateral fragments require an individual approach, e. g. posterolateral or posteromedial. If necessary, osteotomy of the femoral epicondyles can improve joint access for reduction control. Injuries to the posterior columns should be anatomically reconstructed and biomechanically correctly addressed via posterior approaches. Bony posterior cruciate ligament tears can be refixed via a minimally invasive posteromedial approach.

Dissecting Fission Yeast Shelterin Interactions via MICro-MS Links Disruption of Shelterin Bridge to Tumorigenesis

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Jinqiang Liu

2015-09-01

Full Text Available Shelterin, a six-member complex, protects telomeres from nucleolytic attack and regulates their elongation by telomerase. Here, we have developed a strategy, called MICro-MS (Mapping Interfaces via Crosslinking-Mass Spectrometry, that combines crosslinking-mass spectrometry and phylogenetic analysis to identify contact sites within the complex. This strategy allowed identification of separation-of-function mutants of fission yeast Ccq1, Poz1, and Pot1 that selectively disrupt their respective interactions with Tpz1. The various telomere dysregulation phenotypes observed in these mutants further emphasize the critical regulatory roles of Tpz1-centered shelterin interactions in telomere homeostasis. Furthermore, the conservation between fission yeast Tpz1-Pot1 and human TPP1-POT1 interactions led us to map a human melanoma-associated POT1 mutation (A532P to the TPP1-POT1 interface. Diminished TPP1-POT1 interaction caused by hPOT1-A532P may enable unregulated telomere extension, which, in turn, helps cancer cells to achieve replicative immortality. Therefore, our study reveals a connection between shelterin connectivity and tumorigenicity.

Geologic studies of the Columbia Plateau: a status report

International Nuclear Information System (INIS)

Myers, C.W.; Price, S.M.

1979-10-01

The results of recent geologic studies of the Columbia Plateau, with emphasis on work completed under the Basalt Waste Isolation Project, Rockwell Hanford Operations, are summarized in this report. Geologic studies were performed mostly during the period from 1977 to 1979. The major objective of these studies was to examine the feasibility of using deep underground tunnels mined into Columbia River basalt beneath the Hanford Site for final storage of nuclear waste. The results are presented in four chapters: Introduction; Regional Geology; Pasco Basin Geology; and Seismicity and Tectonics. Results from surface mapping and remote sensing studies in the Washington State portion of the Columbia Plateau are presented in the Regional Geology chapter. Results from surface mapping, borehole studies, and geophysical surveys in the Pasco Basin are presented in the Pasco Basin Geology chapter. Results that relate to the tectonic stability of the Pasco Basin and Columbia Plateau and discussion of findings from earthquake monitoring in the region for the past ten years are summarized in the Seismicity and Tectonics chapter. A volume of Appendices is included. This volume contains a description of study tasks, a description of the methodology used in geophysical surveys the geophysical survey results, a summary of earthquake records in eastern Washington, a description of tectonic provinces, and a preliminary description of the regional tectonic setting of the Columbia Plateau

Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography.

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Yu-Yen Chen

Full Text Available To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001, thicker lens (4.77mm vs. 5.11mm; p<0.001, shorter axial length (23.16mm vs. 22.63mm; p<0.001, smaller relative lens position (2.28 vs. 2.16; p<0.001 and larger lens/axial length factor (2.06 vs. 2.26; p<0.001. However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05.Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

Energy Technology Data Exchange (ETDEWEB)

Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

2008-10-01

We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

(Bos grunniens) in Qinghai-Tibetan Plateau

African Journals Online (AJOL)

DR. NJ TONUKARI

2012-10-30

Oct 30, 2012 ... Qinghai-Tibetan Plateau, as it represents a unique bovine species adapted to ..... al., 1993; Udina et al., 2003), mastitis caused by. Staphylococcus sp. ... for prevention and treatment in many cases (Gerald et al., 2003). But in ...

Field Measurement and Evaluation of the Passive and Active Solar Heating Systems for Residential Building Based on the Qinghai-Tibetan Plateau Case

Directory of Open Access Journals (Sweden)

Zhijian Liu

2017-10-01

Full Text Available Passive and active solar heating systems have drawn much attention and are widely used in residence buildings in the Qinghai-Tibetan plateau due to its high radiation intensity. In fact, there is still lack of quantitative evaluation of the passive and active heating effect, especially for residential building in the Qinghai-Tibetan plateau areas. In this study, three kinds of heating strategies, including reference condition, passive solar heating condition and active solar heating condition, were tested in one demonstration residential building. The hourly air temperatures of each room under different conditions were obtained and analyzed. The results show the indoor air temperature in the living room and bedrooms (core zones was much higher than that of other rooms under both passive and active solar heating conditions. In addition, the heating effect with different strategies for core zones of the building was evaluated by the ratio of indoor and outdoor degree hour, which indicates that solar heating could effectively reduce the traditional energy consumption and improve the indoor thermal environment. The passive solar heating could undertake 49.8% degree hours for heating under an evaluation criterion of 14 °C and the active solar heating could undertake 75% degree hours for heating under evaluation criterion of 18 °C, which indicated that solar heating could effectively reduce the traditional energy consumption and improve the indoor thermal environment in this area. These findings could provide reference for the design and application of solar heating in similar climate areas.

Vegetation greenness trend (2000 to 2009) and the climate controls in the Qinghai-Tibetan Plateau

Science.gov (United States)

Zhang, Li; Guo, Huadong; Ji, Lei; Lei, Liping; Wang, Cuizhen; Yan, Dongmei; Li, Bin; Li, Jing

2013-01-01

The Qinghai-Tibetan Plateau has been experiencing a distinct warming trend, and climate warming has a direct and quick impact on the alpine grassland ecosystem. We detected the greenness trend of the grasslands in the plateau using Moderate Resolution Imaging Spectroradiometer data from 2000 to 2009. Weather station data were used to explore the climatic drivers for vegetation greenness variations. The results demonstrated that the region-wide averaged normalized difference vegetation index (NDVI) increased at a rate of 0.036  yr−1. Approximately 20% of the vegetation areas, which were primarily located in the northeastern plateau, exhibited significant NDVI increase trend (p-value plateau. A strong positive relationship between NDVI and precipitation, especially in the northeastern plateau, suggested that precipitation was a favorable factor for the grassland NDVI. Negative correlations between NDVI and temperature, especially in the southern plateau, indicated that higher temperature adversely affected the grassland growth. Although a warming climate was expected to be beneficial to the vegetation growth in cold regions, the grasslands in the central and southwestern plateau showed a decrease in trends influenced by increased temperature coupled with decreased precipitation.

THE LONG-LIVED UV ''PLATEAU'' OF SN 2012aw

Energy Technology Data Exchange (ETDEWEB)

Bayless, Amanda J.; Roming, Peter W. A. [Southwest Research Institute, Department of Space Science, 6220 Culebra Road, San Antonio, TX 78238 (United States); Pritchard, Tyler A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Kuin, Paul [Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Brown, Peter J. [Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843-4242 (United States); Botticella, Maria Teresa; Dall' Ora, Massimo [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli (Italy); Frey, Lucille H.; Even, Wesley; Fryer, Chris L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maund, Justyn R.; Fraser, Morgan [Astrophysics Research Center, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom)

2013-02-10

Observations with the Swift UV Optical Telescope have unambiguously uncovered for the first time a long-lived, UV ''plateau'' in a Type II-P supernova (SN). Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band light curves initially declined rapidly, but 27 days after the explosion the light curves flattened. Some possible sources of the UV plateau are the same thermal process that causes the optical plateau, heating from radioactive decay, or a combination of both processes.

A Comparative Study of the Electrical Structure of Circum Tibetan Plateau Orogenic Belts and its Tectonic Implications

Science.gov (United States)

Jin, Sheng; Zhang, Letian; Wei, Wenbo; Ye, Gaofeng; Jing, Jianen; Dong, Hao; Xie, Chengliang; Yin, Yaotian

2017-04-01

The Tibetan Plateau, as known as "roof of the world", was created through the on-going continent-continent collision between the Indian and Eurasian plates since 55 Ma. As the process continues, the plateau is growing both vertically and horizontally. The horizontal expansion of the plateau is blocked by the Yangtze block in the east, the Tarim block in the north, and the Ordos block in the northeast, and consequently lead to the formation of the circum Tibetan plateau orogenic belts. To better understand the mechanism behind this process, we conducted a comparative study by collecting 7 magnetotelluric (MT) profiles over the margins of the Tibetan plateau, namely, the INDEPTH 100, 700 and 800 lines in the southern Tibet, the INDEPTH 4000 and 5000 lines across the Altyn Tagh fault on the northern margin of the plateau, as well as other two profiles across the Haiyuan fault and the Longmenshan fault on the northeastern and eastern margins of the plateau deployed under the framework of project SinoProbe. The electrical features of the stable blocks surrounding the Tibetan plateau are generally resistive, while crustal conductive layers are found to be wide spread within the plateau. The southern margin of the Tibetan plateau is characterized by large scale underthrust of the Indian lithosphere beneath the plateau. This intense converging process created the thrust fault system distributed along the southern margin of the Tibetan plateau over 1000 km. Crustal conductive layers discovered in southern Tibet are generally associated with the southward crustal flow that originated from the lower crust within the plateau and exhumed along the thrust belts in the Himalayas. On the eastern margin of the Tibetan plateau, the electrical structures suggest that the Yangtze block wedged into the Tibetan lithosphere and caused decoupling between the crust and upper mantel. Large scale conductors discovered beneath the Songpan-Ganze block reflect that the eastward crustal flow was

Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai–Tibetan Plateau

International Nuclear Information System (INIS)

Yi Shuhua; Zhou Zhaoye; Ren Shilong; Xu Ming; Qin Yu; Chen Shengyun; Ye Baisheng

2011-01-01

Permafrost on the Qinghai–Tibetan Plateau (QTP) has degraded over the last few decades. Its ecological effects have attracted great concern. Previous studies focused mostly at plot scale, and hypothesized that degradation of permafrost would cause lowering of the water table and drying of shallow soil and then degradation of alpine grassland. However, none has been done to test the hypothesis at basin scale. In this study, for the first time, we investigated the relationships between land surface temperature (LST) and fractional vegetation cover (FVC) in different types of permafrost zone to infer the limiting condition (water or energy) of grassland growth on the source region of Shule River Basin, which is located in the north-eastern edge of the QTP. LST was obtained from MODIS Aqua products at 1 km resolution, while FVC was upscaled from quadrat (50 cm) to the same resolution as LST, using 30 m resolution NDVI data of the Chinese HJ satellite. FVC at quadrat scale was estimated by analyzing pictures taken with a multi-spectral camera. Results showed that (1) retrieval of FVC at quadrat scale using a multi-spectral camera was both more accurate and more efficient than conventional methods and (2) the limiting factor of vegetation growth transitioned from energy in the extreme stable permafrost zone to water in the seasonal frost zone. Our study suggested that alpine grassland would respond differently to permafrost degradation in different types of permafrost zone. Future studies should consider overall effects of permafrost degradation, and avoid the shortcomings of existing studies, which focus too much on the adverse effects.

Mapping the plateau of novices in virtual reality simulation training of mastoidectomy

DEFF Research Database (Denmark)

A.W. Andersen, Steven; Konge, Lars; Mikkelsen, Peter Trier

2016-01-01

To explore why novices' performance plateau in directed, self-regulated virtual reality (VR) simulation training and how performance can be improved.......To explore why novices' performance plateau in directed, self-regulated virtual reality (VR) simulation training and how performance can be improved....

Plateau Waves of Intracranial Pressure and Partial Pressure of Cerebral Oxygen.

Science.gov (United States)

Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

2016-01-01

This study investigates 55 intracranial pressure (ICP) plateau waves recorded in 20 patients after severe traumatic brain injury (TBI) with a focus on a moving correlation coefficient between mean arterial pressure (ABP) and ICP, called PRx, which serves as a marker of cerebrovascular reactivity, and a moving correlation coefficient between ABP and cerebral partial pressure of oxygen (pbtO2), called ORx, which serves as a marker for cerebral oxygen reactivity. ICP and ICPamplitude increased significantly during the plateau waves, whereas CPP and pbtO2 decreased significantly. ABP, ABP amplitude, and heart rate remained unchanged. In 73 % of plateau waves PRx increased during the wave. ORx showed an increase during and a decrease after the plateau waves, which was not statistically significant. Our data show profound cerebral vasoparalysis on top of the wave and, to a lesser extent, impairment of cerebral oxygen reactivity. The different behavior of the indices may be due to the different latencies of the cerebral blood flow and oxygen level control mechanisms. While cerebrovascular reactivity is a rapidly reacting mechanism, cerebral oxygen reactivity is slower.

Genetic evidence of paleolithic colonization and neolithic expansion of modern humans on the tibetan plateau.

Science.gov (United States)

Qi, Xuebin; Cui, Chaoying; Peng, Yi; Zhang, Xiaoming; Yang, Zhaohui; Zhong, Hua; Zhang, Hui; Xiang, Kun; Cao, Xiangyu; Wang, Yi; Ouzhuluobu; Basang; Ciwangsangbu; Bianba; Gonggalanzi; Wu, Tianyi; Chen, Hua; Shi, Hong; Su, Bing

2013-08-01

Tibetans live on the highest plateau in the world, their current population size is approximately 5 million, and most of them live at an altitude exceeding 3,500 m. Therefore, the Tibetan Plateau is a remarkable area for cultural and biological studies of human population history. However, the chronological profile of the Tibetan Plateau's colonization remains an unsolved question of human prehistory. To reconstruct the prehistoric colonization and demographic history of modern humans on the Tibetan Plateau, we systematically sampled 6,109 Tibetan individuals from 41 geographic populations across the entire region of the Tibetan Plateau and analyzed the phylogeographic patterns of both paternal (n = 2,354) and maternal (n = 6,109) lineages as well as genome-wide single nucleotide polymorphism markers (n = 50) in Tibetan populations. We found that there have been two distinct, major prehistoric migrations of modern humans into the Tibetan Plateau. The first migration was marked by ancient Tibetan genetic signatures dated to approximately 30,000 years ago, indicating that the initial peopling of the Tibetan Plateau by modern humans occurred during the Upper Paleolithic rather than Neolithic. We also found evidences for relatively young (only 7-10 thousand years old) shared Y chromosome and mitochondrial DNA haplotypes between Tibetans and Han Chinese, suggesting a second wave of migration during the early Neolithic. Collectively, the genetic data indicate that Tibetans have been adapted to a high altitude environment since initial colonization of the Tibetan Plateau in the early Upper Paleolithic, before the last glacial maximum, followed by a rapid population expansion that coincided with the establishment of farming and yak pastoralism on the Plateau in the early Neolithic.

Changes in Cerebral Partial Oxygen Pressure and Cerebrovascular Reactivity During Intracranial Pressure Plateau Waves.

Science.gov (United States)

Lang, Erhard W; Kasprowicz, Magdalena; Smielewski, Peter; Pickard, John; Czosnyka, Marek

2015-08-01

Plateau waves in intracranial pressure (ICP) are frequently recorded in neuro intensive care and are not yet fully understood. To further investigate this phenomenon, we analyzed partial pressure of cerebral oxygen (pbtO2) and a moving correlation coefficient between ICP and mean arterial blood pressure (ABP), called PRx, along with the cerebral oxygen reactivity index (ORx), which is a moving correlation coefficient between cerebral perfusion pressure (CPP) and pbtO2 in an observational study. We analyzed 55 plateau waves in 20 patients after severe traumatic brain injury. We calculated ABP, ABP pulse amplitude (ampABP), ICP, CPP, pbtO2, heart rate (HR), ICP pulse amplitude (ampICP), PRx, and ORx, before, during, and after each plateau wave. The analysis of variance with Bonferroni post hoc test was used to compare the differences in the variables before, during, and after the plateau wave. We considered all plateau waves, even in the same patient, independent because they are separated by long intervals. We found increases for ICP and ampICP according to our operational definitions for plateau waves. PRx increased significantly (p = 0.00026), CPP (p pressure remains stable in ICP plateau waves, while cerebral autoregulatory indices show distinct changes, which indicate cerebrovascular reactivity impairment at the top of the wave. PbtO2 decreases during the waves and may show a slight overshoot after normalization. We assume that this might be due to different latencies of the cerebral blood flow and oxygen level control mechanisms. Other factors may include baseline conditions, such as pre-plateau wave cerebrovascular reactivity or pbtO2 levels, which differ between studies.

Cenozoic mountain building on the northeastern Tibetan Plateau

Science.gov (United States)

Lease, Richard O.

2014-01-01

Northeastern Tibetan Plateau growth illuminates the kinematics, geodynamics, and climatic consequences of large-scale orogenesis, yet only recently have data become available to outline the spatiotemporal pattern and rates of this growth. I review the tectonic history of range growth across the plateau margin north of the Kunlun fault (35°–40°N) and east of the Qaidam basin (98°–107°E), synthesizing records from fault-bounded mountain ranges and adjacent sedimentary basins. Deformation began in Eocene time shortly after India-Asia collision, but the northeastern orogen boundary has largely remained stationary since this time. Widespread middle Miocene–Holocene range growth is portrayed by accelerated deformation, uplift, erosion, and deposition across northeastern Tibet. The extent of deformation, however, only expanded ~150 km outward to the north and east and ~150 km laterally to the west. A middle Miocene reorganization of deformation characterized by shortening at various orientations heralds the onset of the modern kinematic regime where shortening is coupled to strike slip. This regime is responsible for the majority of Cenozoic crustal shortening and thickening and the development of the northeastern Tibetan Plateau.

The medicinal plants of Frangensko Plateau (Northeastern Bulgaria)

Science.gov (United States)

Zahariev, Dimcho; Kacheva, Cvetelina

2015-12-01

The Frangensko Plateau is located in the northeastern part of Bulgaria and covers an area of 360 km2. On the territory of the plateau there are two protected areas, as well as two areas of the European ecological network NATURA 2000. The study of the medicinal plants on the territory of the Frangensko Plateau is made for the first time. As a result of our research we found 362 species of vascular plants from 242 genera and 80 families. The most of the families and the genera are represented by a small number of inferior taxa. The analysis of their life form indicates that the hemicryptophytes dominate with 39.50%, followed by the phanerophytes (22.10%). The biological types are represented mainly by perennial herbaceous plants (52.21%), annual herbaceous plants (14.09%) and trees (10.50%). There are 8 types of floristic elements divided in 32 groups. The largest percentage of species is of European type (51.93%). Among the medicinal plants, there are two Balkan endemic species, one Bulgarian endemic species and 30 relic species. Thirty four species with protection statute are described. The anthropophytes among the medicinal plants are 242 species (66.85%).

Intraoperative study on anthropometry and gender differences of the proximal tibial plateau at the arthroplasty resection surface.

Science.gov (United States)

Yang, Bo; Yu, Jiakuo; Gong, Xi; Chen, Lianxu; Wang, Yongjian; Wang, Jian; Wang, Haijun; Zhang, Jiying

2014-01-01

The tibial plateau is asymmetric with a larger medial plateau. We observed from clinical practice that the shape of the tibial plateau does not always present a larger medial plateau. Tibial plateau also showed other shapes. The purpose of this study was to analyze the anthropometric data of the proximal tibia in a large group of Chinese patients undergoing total knee arthroplasty and to investigate the morphology of the resected proximal tibial surface and its gender differences. A total of 822 knees (164 males, 658 females) from the Chinese population were measured intraoperatively for medial anteroposterior (MAP) and lateral anteroposterior (LAP) dimensions of the resected proximal tibial surface. The difference of MAP and LAP (DML) was also calculated as MAP minus LAP. We then classified the data into three groups based on the DML (2 mm) to analyze the morphology of the proximal tibia and its distribution between male and female. The shape of proximal tibial plateau was of three types: larger medial plateau type, symmetric type, and larger lateral plateau type. There were significant differences between males and females in relation to the shape distribution of the proximal tibial plateau (P 2 mm and 120 of 822 (14.6%) tibia having a DMLDMLs to better match the different anthropometry of the resected tibial surface.

[The pathogenic ecology research on plague in Qinghai plateau].

Science.gov (United States)

Dai, Rui-xia; Wei, Bai-qing; Li, Cun-xiang; Xiong, Hao-ming; Yang, Xiao-yan; Fan, Wei; Qi, Mei-ying; Jin, Juan; Wei, Rong-jie; Feng, Jian-ping; Jin, Xing; Wang, Zu-yun

2013-12-01

To study the pathogenic ecology characteristics of plague in Qinghai plateau. Applied molecular biology techniques, conventional technologies and geographic information system (GIS) to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc.of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012. The ecotypes of these strains were Qingzang plateau (91.49%, 871/952),Qilian mountain (6.41%, 61/952) and Microtus fuscus (1.26%, 12/952).83.6% (796/952) of these strains contained all the 4 virulence factors (Fr1, Pesticin1,Virulence antigen, and Pigmentation), 93.26% (367/392) were velogenic strains confirmed by virulence test.725 Yersinia pestis strains were separated from Qinghai plateau plague foci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid, the Mr were 6×10(6), 7×10(6), 23×10(6), 27×10(6), 30×10(6), 45×10(6), 52×10(6), 65×10(6) and 92×10(6) respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6×10(6), 45×10(6), 65×10(6). Meanwhile, the strains carrying large plasmid (52×10(6), 65×10(6) and 92×10(6)) were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague foci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague foci were given priority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% (471/841), genomovar 5 accounted for 23.07% (194/841). Besides, 3 new genomovars, including new 1(62 strains), new 2(52 strains), new 3(48 strains) were newly founded, and 12 strains of Microtus fuscus plague foci were genomovar 14. The main host and media of Qinghai plateau plague foci directly affected the spatial

[Coupling coordinated development of ecological-economic system in Loess Plateau].

Science.gov (United States)

Zhang, Qing-Feng; Wu, Fa-Qi; Wang, Li; Wang, Jian

2011-06-01

Based on system theory, a coupling coordinated development model of ecological-economic system in Loess Plateau was established, and the evaluation criteria and basic types of the coordinated development of the ecological-economic system were proposed. The county-level coupling coordinated development of the ecological-economic system was also discussed, based on the local characteristics. The interactions between the ecological and economic systems in Loess Plateau could be divided into four stages, i.e., seriously disordered development stage, mild-disordered development stage, low-level coordinated development stage, and high level well-coordinated development stage. At each stage, there existed a cyclic process of profit and loss-antagonist-running-dominant-synchronous development. The coupling development degree of the ecological-economic system in Loess Plateau was overall at a lower level, being about 62.7% of the counties at serious disorder, 30.1% of the counties at mild disorder, and 7.1% of the counties at low but coordinated level. The coupling development degree based on the model established in this study could better reflect the current social-economic and ecological environment situations, especially the status of coordination. To fully understand the coupling of ecological-economic system and to adopt appropriate development mode would be of significance to promote the county-level coordinated development in Loess Plateau.

Mapping risk of plague in Qinghai-Tibetan Plateau, China.

Science.gov (United States)

Qian, Quan; Zhao, Jian; Fang, Liqun; Zhou, Hang; Zhang, Wenyi; Wei, Lan; Yang, Hong; Yin, Wenwu; Cao, Wuchun; Li, Qun

2014-07-10

Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed. Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously. We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague. This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau.

[Spatial heterogeneity of soil moisture of mountain apple orchards with rainwater collection and infiltration (RWCI) system in the Loess Plateau, China].

Science.gov (United States)

Song, Xiao Lin; Zhao, Xi Ning; Gao, Xiao Dong; Wu, Pu Te; Ma, Wen; Yao, Jie; Jiang, Xiao Li; Zhang, Wei

2017-11-01

Water scarcity is a critical factor influencing rain-fed agricultural production on the Loess Plateau, and the exploitation of rainwater is an effective avenue to alleviate water scarcity in this area. This study was conducted to investigate the spatial and temporal distribution of soil moisture in the 0-300 cm under a 21-year-old apple orchard with the rainwater collection and infiltration (RWCI) system by using a time domain reflectometer (TDR) probe on the Loess Plateau. The results showed that there was a low soil moisture zone in the 40-80 cm under the CK, and the RWCI system significantly increased soil moisture in this depth interval. Over this depth, the annual average soil moisture under RWCI 40 , RWCI 60 and RWCI 80 was 39.2%, 47.2% and 29.1% higher than that of bare slope (BS) and 75.3%, 85.4% and 62.7% higher than that of CK, respectively. The maximum infiltration depth of water under RWCI 40 , RWCI 60 and RWCI 80 was 80 cm, 120 cm and 180 cm, respectively, and the soil moisture in the 0-60, 0-100 and 0-120 cm was more affected by RWCI 40 , RWCI 60 and RWCI 80 , respectively. Over the whole growth period of apple tree, the maximum value of soil moisture content in the 0-300 cm existed in the RWCI 80 treatment, followed by the RWCI 40 and RWCI 60 treatments. Overall, the RWCI system is an effective meaning of transforming rainwater to available water resources and realizing efficient use of agricultural water on the Loess Plateau.

A pliocene cliff-line around the Giza Pyramids Plateau, Egypt

OpenAIRE

Aigner, Thomas

1982-01-01

Aigner, T., 1983. A Pliocene cliff-line around the Giza Pyramids Plateau, Egypt. Palaeogeogr., Palaeoclimatol., Palaeoecol., 4 2 : 313—322. Escarpments bordering the Giza Pyramids Plateau represent the cliff-line of a Pliocene transgression up the pre-Nile ("Eonile") Valley. Geomorphologically, a limestone cliff can be distinguished from a slip-block shore associated with a distinct fining-up sequence. Differences in bedrock lithology and in structure (Joint pattern, faults) are morphogen...

Crop characteristics and their temporal change on the Loess Plateau of China

NARCIS (Netherlands)

Wu Yongqiu,; Xie Kunqing,; Zhang Qingchun,; Zhnag Yan,; Xie Yun,; Zhang Guanghui,; Zhang Wenbo,; Ritsema, C.J.

2003-01-01

Crop characteristics with obvious seasonal changes strongly influence soil loss. The purpose of this study is to measure and analyze the plant characteristics and their seasonal change in the Loess Plateau. A small watershed, Danangou in the Loess Plateau of north China, was selected for this study.

[Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

Science.gov (United States)

Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

2013-06-11

To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

Study on the relevance of some of the description methods for plateau-honed surfaces

International Nuclear Information System (INIS)

Yousfi, M; Mezghani, S; Demirci, I; El Mansori, M

2014-01-01

Much work has been undertaken in recent years into the determination of a complete parametric description of plateau-honed surfaces with the intention of making a link between the process conditions, the surface topography and the required functional performances. Different advanced techniques (plateau/valleys decomposition using the normalized Abbott–Firestone curve or morphological operators, multiscale decomposition using continuous wavelets transform, etc) were proposed and applied in different studies. This paper re-examines the current state of developments and addresses a discussion on the relevance of the different proposed parameters and characterization methods for plateau-honed surfaces by considering the control loop manufacturing-characterization-function. The relevance of appropriate characterization is demonstrated through two experimental studies. They consider the effect of the most plateau honing process variables (the abrasive grit size and abrasive indentation velocity in finish-honing and the plateau-honing stage duration and pressure) on cylinder liner surface textures and hydrodynamic friction of the ring-pack system. (paper)

Geothermic analysis of high temperature hydrothermal activities area in Western plateau of Sichuan province, China

Science.gov (United States)

Zhang, J.

2016-12-01

There is a high temperature hydrothermal activity area in the western plateau of Sichuan. More than 200 hot springs points have been found in the region, including 11 hot spring water temperature above local boiling point. Most of these distribute along Jinshajjiang fracture, Dege-Xiangcheng fracture, Ganzi-Litang fracture as well as Xianshuihe fracture, and form three high-temperature hydrothermal activity strips in the NW-SE direction. Using gravity, magnetic, seismic and helium isotope data, this paper analyzed the crust-mantle heat flow structure, crustal heat source distribution and water heating system. The results show that the geothermal activity mainly controlled by the "hot" crust. The ratio of crustal heat flow and surface heat flow is higher than 60%. In the high temperature hydrothermal activities area, there is lower S wave velocity zone with VsGeothermal water mainly reserve in the Triassic strata of the containing water good carbonate rocks, and in the intrusive granite which is along the fault zone. The thermal energy of Surface heat thermal activities mainly comes from the high-temperature hot source which is located in the middle and lower crust. Being in the deep crustal fracture, the groundwater infiltrated to the deep crust and absorbed heat, then, quickly got back to the surface and formed high hot springs.

Prevalence of sickle cell disease among children attending plateau specialist hospital, Jos, Nigeria

Directory of Open Access Journals (Sweden)

Nanbur Stephen

2018-01-01

Full Text Available Background: An estimate of 250,000 children are born annually with sickle cell disease (SCD worldwide and 75%–85% of the affected children are born in Africa; where mortality rates for those under age 5 years range from 50% to 80%. Objective: The present study was conducted to estimate the prevalence of SCD among children in Plateau State Specialist Hospital (PSSH, Jos, Nigeria. Methodology: Ethical approval was obtained from the Health Research Ethics Committee of the Hospital. Secondary data on age, gender, and region from the case notes of infants, children and/or adolescents; who received medical care in PSSH from 2012 to 2014 were used. Data were analyzed using frequency tables and Chi-square statistics. Results: The findings revealed that the prevalence of SCD in PSSH, Jos from 2012 to 2014 was 26.9/1000 population of pediatric patients. There was a gradual increase in the prevalence rate from 25.8/1000 in 2012 to 26.8/1000 in 2013 and 28.1/1000 in 2014. However, the case fatality rate of SCD gradually decreased from 15.4% in 2012 to 11.1% in 2013 and 10.3% in 2014. Chi-square test shows that the prevalence of the disease in relation to sex, age, and residence was not statistically significant (P > 0.05. Even though the case fatality rate of the disease decreased, its prevalence increased during the study. Conclusion: Therefore, preventive measure for SCD such as premarital genetic screening and counseling should be emphasized, especially in the southern and central geopolitical zones of Plateau state, where the prevalence was found to be higher.

Analysis of soil hydraulic and thermal properties for land surface modeling over the Tibetan Plateau

Science.gov (United States)

Zhao, Hong; Zeng, Yijian; Lv, Shaoning; Su, Zhongbo

2018-06-01

Soil information (e.g., soil texture and porosity) from existing soil datasets over the Tibetan Plateau (TP) is claimed to be inadequate and even inaccurate for determining soil hydraulic properties (SHP) and soil thermal properties (STP), hampering the understanding of the land surface process over TP. As the soil varies across three dominant climate zones (i.e., arid, semi-arid and subhumid) over the TP, the associated SHP and STP are expected to vary correspondingly. To obtain an explicit insight into the soil hydrothermal properties over the TP, in situ and laboratory measurements of over 30 soil property profiles were obtained across the climate zones. Results show that porosity and SHP and STP differ across the climate zones and strongly depend on soil texture. In particular, it is proposed that gravel impact on porosity and SHP and STP are both considered in the arid zone and in deep layers of the semi-arid zone. Parameterization schemes for porosity, SHP and STP are investigated and compared with measurements taken. To determine the SHP, including soil water retention curves (SWRCs) and hydraulic conductivities, the pedotransfer functions (PTFs) developed by Cosby et al. (1984) (for the Clapp-Hornberger model) and the continuous PTFs given by Wösten et al. (1999) (for the Van Genuchten-Mualem model) are recommended. The STP parameterization scheme proposed by Farouki (1981) based on the model of De Vries (1963) performed better across the TP than other schemes. Using the parameterization schemes mentioned above, the uncertainties of five existing regional and global soil datasets and their derived SHP and STP over the TP are quantified through comparison with in situ and laboratory measurements. The measured soil physical properties dataset is available at https://data.4tu.nl/repository/uuid:c712717c-6ac0-47ff-9d58-97f88082ddc0" target="_blank">https://data.4tu.nl/repository/uuid:c712717c-6ac0-47ff-9d58-97f88082ddc0.

Complex Medial Meniscus Tears Are Associated With a Biconcave Medial Tibial Plateau.

Science.gov (United States)

Barber, F Alan; Getelman, Mark H; Berry, Kathy L

2017-04-01

To determine whether an association exists between a biconcave medial tibial plateau and complex medial meniscus tears. A consecutive series of stable knees undergoing arthroscopy were evaluated retrospectively with the use of preoperative magnetic resonance imaging (MRI), radiographs, and arthroscopy documented by intraoperative videos. Investigators independently performed blinded reviews of the MRI or videos. Based on the arthroscopy findings, medial tibial plateaus were classified as either biconcave or not biconcave. A transverse coronal plane ridge, separating the front of the tibial plateau from the back near the inner margin of the posterior body of the medial meniscus, was defined as biconcave. The medial plateau slope was calculated with MRI sagittal views. General demographic information, body mass index, and arthroscopically confirmed knee pathology were recorded. A total of 179 consecutive knees were studied from July 2014 through August 2015; 49 (27.2%) biconcave medial tibial plateaus and 130 (72.8%) controls were identified at arthroscopy. Complex medial meniscus tears were found in 103. Patients with a biconcave medial tibial plateau were found to have more complex medial meniscus tears (69.4%) than those without a biconcavity (53.1%) (P = .049) despite having lower body mass index (P = .020). No difference in medial tibial plateau slope was observed for biconcavities involving both cartilage and bone, bone only, or an indeterminate group (P = .47). Biconcave medial tibial plateaus were present in 27.4% of a consecutive series of patients undergoing knee arthroscopy. A biconcave medial tibial plateau was more frequently associated with a complex medial meniscus tear. Level III, case-control study. Copyright © 2016 Arthroscopy Association of North America. All rights reserved.

Exploring the undulating plateau: the future of global oil supply.

Science.gov (United States)

Jackson, Peter M; Smith, Leta K

2014-01-13

In this paper, we analyse the factors that will influence long-term oil supply and describe the future form of the global oil supply profile as an 'undulating plateau' rather than an irreversible, short-term peak or an ever upward trend of increasing production. The ultimate transition from a world of relatively plentiful and cheap oil to one of tight supply and high cost will be slow and challenging. An understanding of the signposts for the future path of supply and the drivers of that profile will be critical to managing the transition. The ultimate form of the global supply curve may well be dictated by demand evolution rather than a limited resource endowment in the longer term. Several factors will probably control future global oil supply. We believe that the scale of global oil resource will not constitute a physical supply limit for at least the next two or three decades. However, all categories of oil resources are already more expensive to develop than in the past, requiring high oil prices to stimulate supply growth. Lower rates of oil demand growth relative to economic growth, combined with more challenging supply growth, will probably lead to an undulating plateau sometime after 2040, with demand from non-Organization for Economic Cooperation and Development states continuing to dominate. Upstream investment requirements and oil price volatility will increase towards and beyond the undulating production plateau. In this new world, high oil prices will induce demand destruction, fuel substitution and ever increasing energy efficiency. As we discuss below, the fundamental differences between the IHS Cambridge Energy Research Associates' (IHS CERA) view of the future of oil supply and many peak oil supply models are the timing of the onset of a dramatic slowdown in the rate of growth of supply and the existence or otherwise of a production plateau. We do not dispute that supply will plateau and eventually fall; the question is when, how and at what price

New Hf-Nd evidence supports a heterogeneous plume source for the Caribbean Plateau

International Nuclear Information System (INIS)

Thompson, P.M.E; Kempton, P.D; White, R.V; Kerr, A.C; Tarney, J.; Sauders, A.D

2001-01-01

Hf-Nd systematics provide us with a valuable tool for tracing mantle sources and signatures in ancient or altered rocks. Hf and Nd are amongst the most resistant of all elements to secondary alteration processes (Pearce et al., 1999) and hence can give us insights into the source compositions of altered plateau basalts that other isotopic systems will not. Here we use Hf-Nd systematics to probe the depths of the Cretaceous Caribbean Plateau, in order to characterise its isotope systematics, and hence determine the geochemical nature of the mantle plume responsible for its formation. Much of the plateau is already well characterised in terms of trace elements and isotopes such as Sr, Nd, Pb and Os (Kerr et al., 1997; White et al., 1999; Walker et al., 1999). Unfortunately, isotope system resetting due to sub- solidus alteration, amongst other factors, has ensured that these isotopes have been inconclusive in resolving many important issues, such as whether the Caribbean plateau is a product of an earlier Galapagos plume phase, and how the apparently unique Gorgona komatiites relate to the rest of the Caribbean plateau. We present new Hf-Nd isotopic data which reveal that the Caribbean plume must have been compositionally heterogeneous, comprising at least three different source components. We then compare this 'Caribbean plume' to other present-day plumes, (e.g. Galapagos) and from this speculate whether initial magmatism from the Galapagos plume could indeed have been responsible for the formation of the Caribbean Plateau (au)

Classification Of The Groundwaters Of The Antalya Travertine Plateau By Isotope Techniques

International Nuclear Information System (INIS)

Atilla, O.A.

2002-01-01

The relation between the springs and wells located in Antalya Travertine Plateau is evaluated and classified by using the isotopic composition ({ 3 H(T), ( 18 O), 2 H(D)})of these water resources. The δ 18 O-δD, δ 18 O-TU, δ 18 O-EC, δ 18 O-Cl relations between the water resources in the area are explained and three groups are determined: (1) groundwater with longer residence time discharging in upper plateau and Varsak-Duedenbasi system, (2) groundwater with shorter residence time discharging in the lower plateau, (3) surface waters. The same results obtained by using cluster and principal factor analysis of the hydrogeochemical and isotopic data

Integrated geophysical study of the northeastern margin of Tibetan Plateau

Science.gov (United States)

Shi, L.; Meng, X.; Guo, L.

2011-12-01

Tibetan Plateau, the so-called "Roof of the World", is a direct consequence of collision of the Indian plate with the Eurasian plate starting in the early Cenozoic time. The continent-continent collision is still going on. The northeastern margin of Tibetan Plateau is the front part of the Tibetan Plateau extends to mainland and favorable area for studying uplift and deformation of the Tibetan Plateau. In the past decades, a variety of geophysical methods were conducted to study geodynamics and geological tectonics of this region. We assembled satellite-derived free-air gravity anomalies with a resolution of one arc-minute from the Scripps Institution of Oceanography, and reduced them to obtain Complete Bouguer Gravity Anomalies. Then we gridded Complete Bouguer Gravity Anomalies on a regular grid, and subsequently processed them with the preferential continuation method to attenuate high-frequency noise and analyzed regional and residual anomalies. We also calculated tilt-angle derivative of Complete Bouguer Gravity Anomalies to derive clearer geological structures with more details. Then we calculated the depth distribution of the Moho discontinuity surface in this area by 3D density interface inversion. From the results of preliminary processing, we analyzed the main deep faults and geological tectonics in this region. We extracted seven important profiles' data of Complete Bouguer Gravity Anomalies in this area, and then did forward modeling and inversion on each profile with constraints of geological information and other geophysical data. In the future, we will perform 3D constrained inversion of Complete Bouguer Gravity Anomalies in this region for better understanding deep structure and tectonics of the northeastern margin of Tibetan Plateau. Acknowledgment: We acknowledge the financial support of the SinoProbe project (201011039), the Fundamental Research Funds for the Central Universities (2010ZY26 2011PY0184), and the National Natural Science Foundation

Control of Eospalax baileyi (Plateau Zokor) with arrow traps in western China

NARCIS (Netherlands)

Kong, Yang; Xidong, Li; Gaowei, Xu; Wei, Liu; Meerburg, B.G.

2016-01-01

In order to manage Eospalax (Myospalax) baileyi (Plateau zokors) pests with physical method, the efficacy of four different arrow traps was tested to control the plateau zokor in Sichuan Northwest Prairie, China. Population densities of 39.7-42.1 ha-1 were found in the test plots. Such densities

Migration Imaging of the Java Subduction Zones

Science.gov (United States)

Dokht, Ramin M. H.; Gu, Yu Jeffrey; Sacchi, Mauricio D.

2018-02-01

Imaging of tectonically complex regions can greatly benefit from dense network data and resolution enhancement techniques. Conventional methods in the analysis of SS precursors stack the waveforms to obtain an average discontinuity depth, but smearing due to large Fresnel zones can degrade the fine-scale topography on the discontinuity. To provide a partial solution, we introduce a depth migration algorithm based on the common scattering point method while considering nonspecular diffractions from mantle transition zone discontinuities. Our analysis indicates that, beneath the Sunda arc, the depth of the 410 km discontinuity (the 410) is elevated by 30 km and the 660 km discontinuity (the 660) is depressed by 20-40 km; the region of the strongest anticorrelation is correlated with the morphology of the subducting Indo-Australian slab. In eastern Java, a "flat" 410 coincides with a documented slab gap, showing length scales greater than 400 km laterally and 200 km vertically. This observation could be explained by the arrival of a buoyant oceanic plateau at the Java trench at approximately 8 Ma ago, which may have caused a temporary cessation of subduction and formed a tear in the subducting slab. Our results highlight contrasting depths of the 410 and 660 along the shallow-dipping slab below the Banda trench. The 660, however, becomes significantly uplifted beneath the Banda Sea, which is accompanied by enhanced reflection amplitudes. We interpret these observations as evidence for a subslab low-velocity zone, possibly related to the lower mantle upwelling beneath the subducting slab.

Risk Assessment of Maize Drought Disaster in Agro-Pastoral Transitional Zone in North China

Science.gov (United States)

Jia, H.; Pan, D.

2017-12-01

Agricultural drought is one of the focuses of global concern and one of the natural disasters that affect the agriculture production mostly in China. Farming-pastoral zones in China are located in the monsoon fringe area, precipitation of which is extremely unstable, and drought occurs frequently. The agro-pastoral transitional zone in North China is one of the main producing areas of northern spring maize in northern China, and maize is the second largest grain crop in the region. An assessment of the risk of drought disaster in this region is therefore important in ensuring a reduction in such disasters and an increase in food security. A risk assessment model, EPIC (Environmental Policy Integrated Climate) model, for maize drought disasters based on the Erosion Productivity Impact Calculator crop model is proposed for areas with the topographic characteristics of agro-pastoral transitional zone in North China. The results showed that the hazard risk level for the maize zone of agro-pastoral transitional zone in North China is generally high. Most hazard index values were between 0.4 and 0.5, accounting for 48.77% of total study area. The high-risk areas were mainly distributed in Ordos Plateau (South of Inner Mongolia Autonomous region), South of Ningxia Hui Autonomous Region and Center of Gansu Province. These results provide a scientific basis and support for the reduction of agricultural drought disasters and an increase in food security in the agro-pastoral transitional zone in North China.

Timing and mechanism of the rise of the Shillong Plateau in the Himalayan foreland.

OpenAIRE

Govin, Gwladys; Najman, Yanina Manya Rachel; Copley, Alex; Millar, Ian; Van der Beek, Peter; Huyghe, Pascale; Grujic, Djordje; Davenport, Jesse

2018-01-01

The Shillong Plateau (northeastern India) constitutes the only significant topography in the Himalayan foreland. Knowledge of its surface uplift history is key to understanding topographic development and unraveling tectonic–climate–topographic coupling in the eastern Himalaya. We use the sedimentary record of the Himalayan foreland basin north of the Shillong Plateau to show that the paleo-Brahmaputra river was redirected north and west by the rising plateau at 5.2–4.9 Ma. We suggest that on...

Late-Glacial radiocarbon- and palynostratigraphy in the Swiss Plateau

International Nuclear Information System (INIS)

Ammann, B.; Lotter, A.F.

1989-01-01

A detailed Late-Glacial radiocarbon stratigraphy for the Swiss Plateau has been established on the basis of over 90 accelerator 14 C dates on terrestrial plant macrofossils. A comparison of the radiocarbon ages derived from terrestrial, telmatic and limnic material at different sites on the Swiss Plateau yields a proposal for modifying the zonation system of Welten for the Late-Glacial. By retaining the limits of chronozones and by refining the palynostratigraphic criteria for the limits of biozones, a separation between chrono- and biozonation at the beginning of the Boelling and the Younger Dryas becomes obvious. 54 refs

Increased Tumor Oxygenation and Drug Uptake During Anti-Angiogenic Weekly Low Dose Cyclophosphamide Enhances the Anti-Tumor Effect of Weekly Tirapazamine

Science.gov (United States)

Doloff, J.C.; Khan, N.; Ma, J.; Demidenko, E.; Swartz, H.M.; Jounaidi, Y.

2010-01-01

Metronomic cyclophosphamide treatment is associated with anti-angiogenic activity and is anticipated to generate exploitable hypoxia using hypoxia-activated prodrugs. Weekly administration of tirapazamine (TPZ; 5 mg/kg body weight i.p.) failed to inhibit the growth of 9L gliosarcoma tumors grown s.c. in scid mice. However, the anti-tumor effect of weekly cyclophosphamide (CPA) treatment (140 mg/kg BW i.p.) was substantially enhanced by weekly TPZ administration. An extended tumor free period and increased frequency of tumor eradication without overt toxicity were observed when TPZ was given 3, 4 or 5 days after each weekly CPA treatment. Following the 2nd CPA injection, Electron Paramagnetic Resonance (EPR) Oximetry indicated significant increases in tumor pO2, starting at 48 hr, which further increased after the 3rd CPA injection. pO2 levels were, however, stable in growing untreated tumors. A strong negative correlation (−0.81) between tumor pO2 and tumor volume during 21 days of weekly CPA chemotherapy was observed, indicating increasing tumor pO2 with decreasing tumor volume. Furthermore, CPA treatment resulted in increased tumor uptake of activated CPA. CPA induced increases in VEGF RNA, which reached a maximum on day 1, and in PLGF RNA which was sustained throughout the treatment, while anti-angiogenic host thrombospondin-1 increased dramatically through day 7 post-CPA treatment. Weekly cyclophosphamide treatment was anticipated to generate exploitable hypoxia. However, our findings suggest that weekly CPA treatment induces a functional improvement of tumor vasculature, which is characterized by increased tumor oxygenation and drug uptake in tumors, thus counter-intuitively, benefiting intratumoral activation of TPZ and perhaps other bioreductive drugs. PMID:19754361

Livelihood Vulnerability Assessment Of Farmers and Nomads in Eastern Ecotone of Tibetan Plateau

Science.gov (United States)

Yan, J.; Zhang, Y.

2011-12-01

Livelihood vulnerability assessment provides a scientific basis for anti-poverty of people and regional sustainable development in vulnerable area. Although there are massive discussions on concept of vulnerability, it is still difficult to make it quantitative and to carry out comprehensive appraise. Vulnerability assessments based on sustainable livelihood frame are widely accepted in case studies for attentions to vulnerable groups. However, these case studies are always on regional scale and never reflect how climate change affects people's livelihood and adaptive capability of people. It is necessary to seek vulnerable assessment index system and means based on livelihood process of local people. This paper develops a livelihood vulnerability assessment index system on the basis of sustainable livelihood framework and appraises livelihood vulnerability values of 11 townships, using data of 879 sample households. Livelihood vulnerability assessment index system reflects main risks, livelihood assets and adaptation strategies of local people and government. The results show that livelihood vulnerability level of plateau region is higher than that of mountain to plateau region and mountain gorge region. Manzhang Township in plateau region is the most vulnerable township and nomads there cannot cope with risks of climate change, meadow degeneration and herbs degradation. Upper part of mountain to plateau region and the whole plateau region have high livelihood vulnerability values and local nomads would not cope with risks if no measures are taken by government. The driving forces of livelihood vulnerability include strikes of risks and deficiency of livelihood assets and adaptive capability. Farmers and nomads in high mountain gorge region and lower part of mountain to plateau region can cope with these risks, meanwhile, there are more employment opportunities in second and tertiary industries are needed to help them realize livelihood diversification. Therefore

The first report of Cryptosporidium spp. in Microtus fuscus (Qinghai vole) and Ochotona curzoniae (wild plateau pika) in the Qinghai-Tibetan Plateau area, China.

Science.gov (United States)

Zhang, Xueyong; Jian, Yingna; Li, Xiuping; Ma, Liqing; Karanis, Gabriele; Karanis, Panagiotis

2018-05-01

Cryptosporidium is one of the most important genera of intestinal zoonotic pathogens, which can infect various hosts and cause diarrhoea. There is little available information about the molecular characterisation and epidemiological prevalence of Cryptosporidium spp. in Microtus fuscus (Qinghai vole) and Ochotona curzoniae (wild plateau pika) in the Qinghai-Tibetan Plateau area of Qinghai Province, Northwest China. Therefore, the aim of this study was to determine Cryptosporidium species/genotypes and epidemiological prevalence in these mammals by detecting the SSU rRNA gene by PCR amplification. The Cryptosporidium spp. infection rate was 8.9% (8/90) in Qinghai voles and 6.25% (4/64) in wild plateau pikas. Positive samples were successfully sequenced, and the following Cryptosporidium species were found: C. parvum, C. ubiquitum, C. canis and a novel genotype in Qinghai voles and C. parvum and a novel genotype in wild plateau pikas. This is the first report of Cryptosporidium infections in M. fuscus and wild O. curzoniae in Northwest China. The results suggest the possibility of Cryptosporidium species transmission among these two hosts, the environment, other animals and humans and provide useful molecular epidemiological data for the prevention and control of Cryptosporidium infections in wild animals and the surrounding environments. The results of the present study indicate the existence of Cryptosporidium species infections that have potential public health significance. This is the first report of Cryptosporidium multi-species infections in these animal hosts.

Mean centering of ratio spectra and successive derivative ratio spectrophotometric methods for determination of isopropamide iodide, trifluoperazine hydrochloride and trifluoperazine oxidative degradate

Directory of Open Access Journals (Sweden)

Maha M. Abdelrahman

2016-09-01

Full Text Available Two sensitive, selective and precise stability indicating methods for the determination of isopropamide iodide (ISO, trifluoperazine hydrochloride (TPZ and trifluoperazine oxidative degradate (DEG were developed and validated. Method A is a successive derivative ratio spectrophotometric one, which depends on the successive derivative of ratio spectra in two steps using 0.1 N HCl as a solvent and measuring TPZ at 250.4 and 257.2 nm, ISO at 223 and 228 nm and DEG at 210.6, 213 and 270.2 nm. Method B is mean centering of ratio spectra which depends on using the mean centered ratio spectra in two successive steps and measuring the mean centered values of the second ratio spectra at 322, 355 and 339 nm for TPZ, ISO and DEG, respectively. Factors affecting the developed methods were studied and optimized, moreover, they have been validated as per ICH guidelines and the results demonstrated that the suggested methods are reliable, reproducible and suitable for routine use with short analysis time. Statistical analysis of the two developed methods with the reported one using F- and Student’s t-test showed no significant difference regarding accuracy and precision.

Some practical notes on the land surface modeling in the Tibetan Plateau

Directory of Open Access Journals (Sweden)

K. Yang

2009-05-01

Full Text Available The Tibetan Plateau is a key region of land-atmosphere interactions, as it provides an elevated heat source to the middle-troposphere. The Plateau surfaces are typically characterized by alpine meadows and grasslands in the central and eastern part while by alpine deserts in the western part. This study evaluates performance of three state-of-the-art land surface models (LSMs for the Plateau typical land surfaces. The LSMs of interest are SiB2 (the Simple Biosphere, CoLM (Common Land Model, and Noah. They are run at typical alpine meadow sites in the central Plateau and typical alpine desert sites in the western Plateau.

The identified key processes and modeling issues are as follows. First, soil stratification is a typical phenomenon beneath the alpine meadows, with dense roots and soil organic matters within the topsoil, and it controls the profile of soil moisture in the central and eastern Plateau; all models, when using default parameters, significantly under-estimate the soil moisture within the topsoil. Second, a soil surface resistance controls the surface evaporation from the alpine deserts but it has not been reasonably modeled in LSMs; an advanced scheme for soil water flow is implemented in a LSM, based on which the soil resistance is determined from soil water content and meteorological conditions. Third, an excess resistance controls sensible heat fluxes from dry bare-soil or sparsely vegetated surfaces, and all LSMs significantly under-predict the ground-air temperature gradient, which would result in higher net radiation, lower soil heat fluxes and thus higher sensible heat fluxes in the models. A parameterization scheme for this resistance has been shown to be effective to remove these biases.

Results of the speleological exploration on Pešter plateau

Directory of Open Access Journals (Sweden)

Nešić Dragan

2015-01-01

Full Text Available During the period 2006-2008, basic speleological research was done on Pešter Plateau in Southwestern Serbia. On that occasion, 40 caves were surveyed, 11 of which were measured in detail. Registered caves were grouped on the basis of landscape characteristics and morphogenetic relations. Based on the location and general characteristics of the Pešter karst, it is considered that the objects near Boljare and in the ponor (sinking area of Boroštica are connected to the drainage system of the Pećina nad Vražjim firovima (Vražiji firovi Cave. In morphological terms, the cave Bezdan Kaćunova ravan (Kaćunova Cave near Boljare with its imposing hall is the most important object on Pešter Plateau for the time being. Realized research on Pešter Plateau has the character of basic or initial speleological research, which should be continued in order to solve different problems of karst in this area.

Path of Social Construction in Northwest Sichuan Plateau Pastoral Area

Institute of Scientific and Technical Information of China (English)

2012-01-01

On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly includes social cause in narrow sense,and social management at meso-level.The northwest Sichuan plateau pastoral area is faced with the best policy and development opportunity.However,there are still many weak aspects.Firstly,social structure is not coordinated with economic structure.Secondly,social construction ability of grass-roots government is weak.Thirdly,the ability to respond to public demands is low.Fourthly,there is a big gap in availability of basic public service.Finally,it presents path selection for social construction of northwest Sichuan plateau pastoral area:strengthen social construction ability of grass-roots government;promote social construction with livelihood projects as key projects;boost social construction taking advantage of ecological construction;develop basic public service with the aid of external forces;intensify evaluation system for supervision of social construction works.

Remote sensing of severe convective storms over Qinghai-Xizang Plateau

Science.gov (United States)

Hung, R. J.; Liu, J. M.; Tsao, D. Y.; Smith, R. E.

1984-01-01

The American satellite, GOES-1 was moved to the Indian Ocean at 58 deg E during the First GARP Global Experiment (FGGE). The Qinghai-Xizang Plateau significantly affects the initiation and development of heavy rainfall and severe storms in China, just as the Rocky Mountains influence the local storms in the United States. Satelite remote sensing of short-lived, meso-scale convective storms is particularly important for covering a huge area of a high elevation with a low population density, such as the Qinghai-Xizang Plateau. Results of this study show that a high growth rate of the convective clouds, followed by a rapid collapse of the cloud top, is associated with heavy rainfall in the area. The tops of the convective clouds developed over the Plateau lie between the altitudes of the two tropopauses, while the tops of convective clouds associated with severe storms in the United States usually extend much above the tropopause.

Re-evaluating the 1940s CO2 plateau

Science.gov (United States)

Bastos, Ana; Ciais, Philippe; Barichivich, Jonathan; Bopp, Laurent; Brovkin, Victor; Gasser, Thomas; Peng, Shushi; Pongratz, Julia; Viovy, Nicolas; Trudinger, Cathy M.

2016-09-01

The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940-1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940-1950 ranges between 0.9 and 2.0 Pg C yr-1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr-1 uptake, but it is unlikely to be higher. The impact of the 1940-1942 El Niño on the

Comparison Of Vented And Absolute Pressure Transducers For Water-Level Monitoring In Hanford Site Central Plateau Wells

International Nuclear Information System (INIS)

Mcdonald, J.P.

2011-01-01

Automated water-level data collected using vented pressure transducers deployed in Hanford Site Central Plateau wells commonly display more variability than manual tape measurements in response to barometric pressure fluctuations. To explain this difference, it was hypothesized that vented pressure transducers installed in some wells are subject to barometric pressure effects that reduce water-level measurement accuracy. Vented pressure transducers use a vent tube, which is open to the atmosphere at land surface, to supply air pressure to the transducer housing for barometric compensation so the transducer measurements will represent only the water pressure. When using vented transducers, the assumption is made that the air pressure between land surface and the well bore is in equilibrium. By comparison, absolute pressure transducers directly measure the air pressure within the wellbore. Barometric compensation is achieved by subtracting the well bore air pressure measurement from the total pressure measured by a second transducer submerged in the water. Thus, no assumption of air pressure equilibrium is needed. In this study, water-level measurements were collected from the same Central Plateau wells using both vented and absolute pressure transducers to evaluate the different methods of barometric compensation. Manual tape measurements were also collected to evaluate the transducers. Measurements collected during this study demonstrated that the vented pressure transducers over-responded to barometric pressure fluctuations due to a pressure disequilibrium between the air within the wellbores and the atmosphere at land surface. The disequilibrium is thought to be caused by the relatively long time required for barometric pressure changes to equilibrate between land surface and the deep vadose zone and may be exacerbated by the restriction of air flow between the well bore and the atmosphere due to the presence of sample pump landing plates and well caps. The

1/3 magnetization plateau in a one-dimensional anisotropic ferrimagnet

Energy Technology Data Exchange (ETDEWEB)

Tonegawa, T [Department of Mechanical Engineering, Fukui University of Technology, Fukui 910-8505 (Japan); Sakai, T [Japan Atomic Energy Agency (JAEA), Spring-8, Hyogo 679-5148, and Crest JST, Japan (Japan); Okamoto, K [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Kaburagi, M [Faculty of Cross-Cultural Studies, Kobe University, Kobe 657-8501 (Japan)

2006-11-15

Using mainly numerical methods, we investigate the ground-state magnetization curve of a mixed spin chain with uniaxial single-ion anisotropies, where S = 1 and S = 2 spins are alternating and coupled antiferromagnetically. Special attention is paid to the magnetization plateau, the 1/3-plateau, which appears at one third of the saturation magnetization in the magnetization curve. It is found that there appear three kinds of 1/3-plateaux, one of which has a quantum nature, while the remaining two have a classical (Ising) nature.

Plateau hypoxia attenuates the metabolic activity of intestinal flora to enhance the bioavailability of nifedipine.

Science.gov (United States)

Zhang, Juanhong; Chen, Yuyan; Sun, Yuemei; Wang, Rong; Zhang, Junmin; Jia, Zhengping

2018-11-01

Nifedipine is completely absorbed by the gastrointestinal tract and its pharmacokinetics and metabolism may be influenced by microorganisms. If gut microbes are involved in the metabolism of nifedipine, plateau hypoxia may regulate the bioavailability and the therapeutic effect of nifedipine by altering the metabolic activity of the gut microbiota. We herein demonstrated for the first time that gut flora is involved in the metabolism of nifedipine by in vitro experiments. In addition, based on the results of 16S rRNA analysis of feces in rats after acute plateau, we first confirmed that the plateau environment could cause changes in the number and composition of intestinal microbes. More importantly, these changes in flora could lead to a slower metabolic activity of nifedipine in the body after an acute plateau, resulting in increased bioavailability and therapeutic efficacy of nifedipine. Our research will provide basis and new ideas for changes in the fecal flora of human acutely entering the plateau, and contribute to rational drug use of nifedipine.

Internal tectonic structure of the Central American Wadati-Benioff zone based on analysis of aftershock sequences

Science.gov (United States)

Špičák, Aleš; Hanuš, Václav; Vaněk, Jiří; Běhounková, Marie

2007-09-01

Relocated Engdahl et al. (1998) global seismological data for 10 aftershock sequences were used to analyze the internal tectonic structure of the Central American subduction zone; the main shocks of several of these were the most destructive and often referenced earthquakes in the region (e.g., the 1970 Chiapas, 1983 Osa, 1992 Nicaragua, 1999 Quepos, 2001 El Salvador earthquakes). The spatial analysis of aftershock foci distribution was performed in a rotated Cartesian coordinate system (x, y, z) related to the Wadati-Benioff zone, and not in a standard coordinate system ($\\varphi$, λ, h are latitude, longitude, focal depth, respectively). Available fault plane solutions were also transformed into the plane approximating the Wadati-Benioff zone. The spatial distribution of earthquakes in each aftershock sequence was modeled as either a plane fit using a least squares approximation or a volume fit with a minimum thickness rectangular box. The analysis points to a quasi-planar distribution of earthquake foci in all aftershock sequences, manifesting the appurtenance of aftershocks to fracture zones. Geometrical parameters of fracture zones (strike, dip, and dimensions) hosting individual sequences were calculated and compared with the seafloor morphology of the Cocos Plate. The smooth character of the seafloor correlates with the aftershock fracture zones oriented parallel to the trench and commonly subparallel to the subducting slab, whereas subduction of the Cocos Ridge and seamounts around the Quepos Plateau coincides with steeply dipping fracture zones. Transformed focal mechanisms are almost exclusively (>90%) of normal character.

Strain transformation between tectonic extrusion and crustal thickening in the growth of the Tibetan Plateau

Science.gov (United States)

Liu, M.; Li, Y.; Sun, Y.; Shen, X.

2017-12-01

The Indo-Eurasian continental collision since 50 Ma has thickened the crust to raise the Himalayan-Tibetan Plateau and driven lateral extrusion of Asian lithospheric blocks to affect Cenozoic tectonics in central and east Asia. The relative roles of crustal thickening and tectonic extrusion, and the strain partitioning between them over time and space, remain controversial. We have analyzed the strain rates using GPS velocities, and correlated the results with vertical motion derived from precise leveling. We found that tectonic extrusion largely transforms to crustal thickening near the margins of the Tibetan Plateau. Near the NW margin of the Tibetan Plateau, the shear stain transforms to compressive strain, consistent with neotectonic studies that indicate crustal shortening and uplift. Around the SE margin, shear stain largely terminates in the southern Yunnan province of China. The present-day crustal motion in SE Tibetan Plateau can be well explained by gravitational spreading without invoking plate-edge push as envisioned in the tectonic extrusion model. Using data collected from local seismic arrays, we derived receiver functions to image the lithospheric structures across the Tibetan Plateau and the Alashan block to its north and the Ordos block to its east. Our results indicate that the mantle lithosphere of these bounding Asian blocks has not been reworked by Tibetan tectonics; instead they have acted as restrictive walls to the growing Tibetan Plateau. Our finite element modeling shows that crustal deformation along the margins of the Tibetan Plateau are consistent with the notion that the east- and southeastward extrusion of the Tibetan lithosphere is largely confined to the Tibetan Plateau because of the restrictive bounding blocks of the Asian lithosphere. Thus the tectonic impact of the Indo-Eurasian collision on the Cenozoic Asian tectonics may not be as extensive as previously thought.

Fault-controlled CO2 leakage from natural reservoirs in the Colorado Plateau, East-Central Utah

Science.gov (United States)

Jung, Na-Hyun; Han, Weon Shik; Watson, Z. T.; Graham, Jack P.; Kim, Kue-Young

2014-10-01

The study investigated a natural analogue for soil CO2 fluxes where CO2 has naturally leaked on the Colorado Plateau, East-Central Utah in order to identify various factors that control CO2 leakage and to understand regional-scale CO2 leakage processes in fault systems. The total 332 and 140 measurements of soil CO2 flux were made at 287 and 129 sites in the Little Grand Wash (LGW) and Salt Wash (SW) fault zones, respectively. Measurement sites for CO2 flux involved not only conspicuous CO2 degassing features (e.g., CO2-driven springs/geysers) but also linear features (e.g., joints/fractures and areas of diffusive leakage around a fault damage zone). CO2 flux anomalies were mostly observed along the fault traces. Specifically, CO2 flux anomalies were focused in the northern footwall of the both LGW and SW faults, supporting the existence of north-plunging anticlinal CO2 trap against south-dipping faults as well as higher probability of the north major fault traces as conduits. Anomalous CO2 fluxes also appeared in active travertines adjacent to CO2-driven cold springs and geysers (e.g., 36,259 g m-2 d-1 at Crystal Geyser), ancient travertines (e.g., 5,917 g m-2 d-1), joint zones in sandstone (e.g., 120 g m-2 d-1), and brine discharge zones (e.g., 5,515 g m-2 d-1). These observations indicate that CO2 has escaped through those pathways and that CO2 leakage from these fault zones does not correspond to point source leakage. The magnitude of CO2 flux is progressively reduced from north (i.e. the LGW fault zone, ∼36,259 g m-2 d-1) to south (i.e. the SW fault zone, ∼1,428 g m-2 d-1) despite new inputs of CO2 and CO2-saturated brine to the northerly SW fault from depth. This discrepancy in CO2 flux is most likely resulting from the differences in fault zone architecture and associated permeability structure. CO2-rich fluids from the LGW fault zone may become depleted with respect to CO2 during lateral transport, resulting in an additional decrease in CO2 fluxes

Sensitivity of LUCC on the Surface Temperature of Tibetan Plateau

Science.gov (United States)

Qi, W.; Deng, X.; Wu, F.

2016-12-01

The Tibetan Plateau has an important effect on the ecological security in China, even in Asia, which makes the region become the hot spot in recently research. Under the joint influence of global change and human activities, ecosystem destabilizing and the increasing pressure on resources and environment emerge on the Tibetan Plateau, but the potential spatial sensitivity of land use and land cover changes(LUCC) on surface temperature has not been quantitatively analyzed. This study analyzed the mainly types of LUCC, urbanization, grassland degradation, deforestation on Tibetan Plateau along with Representative Concentration Pathways (RCPs) of the Intergovernmental Panel on Climate Change (IPCC). The LUCC in recent decades was first quantitatively analyzed in this study to give the basic fact with a significant increase in temperatures, reduced precipitation and increased evaporation. This study focused on the future spatio-temporal heterogeneity of the temperature and precipitation. Finally, the influencing factors with LUCC on Tibetan Plateau were simulated with the Weather Research and Forecasting (WRF) model, and the sensitivity of different land use types was spatially analyzed with Singular Value Decomposition (SVD). The results indicate that the large-area alpine grassland plays a more important role in alleviating global warming than other vegetation types do. The changes of the landscape structure resulting from the urban expansion play a significant role in intensifying regional temperature increase. In addition, the effects of LUCC on monthly average temperature change would vary from month to month with obviously spatial heterogeneity.

Plateau onset for correlation dimension: When does it occur?

International Nuclear Information System (INIS)

Ding, M.; Grebogi, C.; Ott, E.; Sauer, T.; Yorke, J.A.

1993-01-01

Chaotic experimental systems are often investigated using delay coordinates. Estimated values of the correlation dimension in delay coordinate space typically increase with the number of delays and eventually reach a plateau (on which the dimension estimate is relatively constant) whose value is commonly taken as an estimate of the correlation dimension D 2 of the underlying chaotic attractor. We report a rigorous result which implies that, for long enough data sets, the plateau begins when the number of delay coordinates first exceeds D 2 . Numerical experiments are presented. We also discuss how lack of sufficient data can produce results that seem to be inconsistent with the theoretical prediction

Three-dimensional Crustal Structure beneath the Tibetan Plateau Revealed by Multi-scale Gravity Analysis

Science.gov (United States)

Xu, C.; Luo, Z.; Sun, R.; Li, Q.

2017-12-01

The Tibetan Plateau, the largest and highest plateau on Earth, was uplifted, shorten and thicken by the collision and continuous convergence of the Indian and Eurasian plates since 50 million years ago, the Eocene epoch. Fine three-dimensional crustal structure of the Tibetan Plateau is helpful in understanding the tectonic development. At present, the ordinary method used for revealing crustal structure is seismic method, which is inhibited by poor seismic station coverage, especially in the central and western plateau primarily due to the rugged terrain. Fortunately, with the implementation of satellite gravity missions, gravity field models have demonstrated unprecedented global-scale accuracy and spatial resolution, which can subsequently be employed to study the crustal structure of the entire Tibetan Plateau. This study inverts three-dimensional crustal density and Moho topography of the Tibetan Plateau from gravity data using multi-scale gravity analysis. The inverted results are in agreement with those provided by the previous works. Besides, they can reveal rich tectonic development of the Tibetan Plateau: (1) The low-density channel flow can be observed from the inverted crustal density; (2) The Moho depth in the west is deeper than that in the east, and the deepest Moho, which is approximately 77 km, is located beneath the western Qiangtang Block; (3) The Moho fold, the directions of which are in agreement with the results of surface movement velocities estimated from Global Positioning System, exists clearly on the Moho topography.This study is supported by the National Natural Science Foundation of China (Grant No. 41504015), the China Postdoctoral Science Foundation (Grant No. 2015M572146), and the Surveying and Mapping Basic Research Programme of the National Administration of Surveying, Mapping and Geoinformation (Grant No. 15-01-08).

Does the climate warming hiatus exist over the Tibetan Plateau?

OpenAIRE

Anmin Duan; Zhixiang Xiao

2015-01-01

The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998–2013 (0.25 °C decade−1), compared with that during 1980–1997 (0.21 °C decade−1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud–ra...

Therapeutical Management of the Tibial Plateau Fractures

Directory of Open Access Journals (Sweden)

Obada B.

2016-11-01

Full Text Available The study was aimed to identify the role of surgical treatment of tibial plateau fractures, its functional outcome and complications. Demographic data for the patients and details of current clinical and radiological follow-up findings were obtained to assess range of motion, clinical stability, alignment of the knee, and posttraumatic arthrosis (Kellgren/Lawrence score. 64 cases of tibial plateau fractures treated by different surgical methods and variuos implants type were studied from 2013 to 2015 and followed-up for minimum period of 6 months. The systematisation of the casuitry was made using Schatzker and AO classifications. The treatment methods consist of: percutaneous cannulated cancellous screws, ORIF with buttress plate with or without bone grafting, locking or nonlocking plates, external fixator. As complications we found: redepression 4 case, malunion 2 cases, knee stiffness 9, wound dehiscence in 1 cases and non-union or infection in none of our cases. The average flexion of the injured knee was significantly lower in comparison with the contralateral side (124.9°/135.2°. Knee stability did not differ statistically significantly. There were no signs of posttraumatic arthrosis in 45% of cases, mild signs in 30%, clear signs in 18%, and severe signs in 7%. As conclusion we found that surgical management of tibial plateau fractures will give excellent anatomical reduction and rigid fixation to restore articular congruity, facilitate early motion and reduce arthrosis risk and hence to achieve optimal knee function. The choice of optimal surgical methods, proper approach and implant is made in relation to fracture type according Schatzker and AO classification.

Past and future spatiotemporal changes in evapotranspiration and effective moisture on the Tibetan Plateau

Science.gov (United States)

Yin, Yunhe; Wu, Shaohong; Zhao, Dongsheng

2013-10-01

evaporative demand has decreased worldwide during the past several decades. This trend is also noted on the Tibetan Plateau, a region that is particularly sensitive to climate change. However, patterns and trends of evapotranspiration and their relationship to drought stress on the Tibetan Plateau are complex and poorly understood. Here, we analyze spatiotemporal changes in evapotranspiration and effective moisture (defined as the ratio of actual evapotranspiration (ETa) to reference crop evapotranspiration (ETo)) based on the modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ). Climate data from 80 meteorological stations on the Tibetan Plateau were compiled for the period 1981-2010 and future climate projections were generated by a regional climate model through the 21st century. The results show regional trends towards decreasing ETo and statistically significant increases in ETa (p stress, because of generally increased effective moisture. Future regional differences are most pronounced in terms of effective moisture, which shows notable increases in the northwestern plateau and decreases in the southeastern plateau. Moreover, the reduced magnitude of effective moisture is likely to intensify in the long term, due mainly to increased evaporative demand.

Parasitisme du safoutier par les Tapinanthus au plateau de Logbessou (Douala, Cameroun

Directory of Open Access Journals (Sweden)

Mony, R.

2014-01-01

Full Text Available Safou Parasitism by Tapinanthus on Logbessou's plateau (Douala, Cameroon. In Cameroon, parasitism by Loranthaceae is a limiting factor of the safou tree cultivation as well as the perishable nature of the fruit which reduces the shelf life. Inventories were carried out in the home gardens of Logbessou's plateau in Douala. All the safou trees likely to produce and located within a perimeter of 200 m x 25 m from the center to the periphery of the plateau were observed and characterized by the circumference of the trunk, the number of tufts of Loranthaceae present on the tree and the taxon of the parasite. Safou trees are primarily parasitized by two species of Tapinanthus. Parasitism rate (34% varied significantly between center and periphery of the plateau. The average number of tufts of Tapinanthus by tree was also significantly different according to the location of the trees and between the two species of Tapinanthus. It is important to investigate the age at which pests significantly affect Safou yields in order to be able to propose adequate control methods when the farmers want to limit the parasitism of this species.

Aeolian processes during the Holocene in Gannan Region, Eastern Tibetan Plateau

Science.gov (United States)

Yang, S.; Cheng, T.; Li, S.; Liang, M.

2016-12-01

Aeolian desertification occurring in the Tibetan Plateau has received attention recently for it has become a severe environmental problem by accelerating the grassland degradation and eco-environment damage. The Gannan Region is located in the northeastern Tibetan Plateau with a mean altitude of 3500m. It is highly sensitive to global environmental change and human disturbance. Serious soil erosion and desertification and extensive land degradation have caused heavy eco-environmental impacts. To investigate the evolution of the desertification in Holocene in the Plateau is of great importance for understanding the desertification trend under the global changes in the Tibetan Plateau. Loess and aeolian sands is a key geological archive related to desertification processes and the past environment changes. In this study a typical 8.5m-thick loess-sands profile named MQQ, was selected at the Maqu city. It is situated on the first terrace (T1) of the Yellow River. Detailed accelerator mass spectrometry (AMS) 14C dating of bulk organic matter content has shown the Aeolian sediments of the MQQ section occurring since the early Holocene. the mass-specific frequency-dependent magnetic susceptibility (χfd) and grainsize records show a clear upward increase in the contents of superparamagnetic grains and fine fractions in grain size, which indicates a gradual wetting trend during the Holocene.The sediment rates change from very high in the early Holocene to low values after 8.2 ka. The wetting process can be divided into three steps: 10.0-8.2 ka, 8.2-3.0 ka and 3.0-present. It indicates that the climate in the eastern Tibetan Plateau was dry during the early Holocene. After that the climate was getting wet gradually. The variations of the westerlies and the Asian monsoon may cause the environmental change in this region.

Resistance of plateau-phase human normal and xeroderma pigmentosum fibroblasts to the cytotoxic effect of ultraviolet light

International Nuclear Information System (INIS)

Chan, G.L.; Little, J.B.

1979-01-01

Clonogenic survival response to 254-nm ultraviolet light was measured in 2 strains of repair-proficient normal human fibroblasts and 4 strains of xeroderma pigmentosum (XP) fibroblasts belonging to complementation groups A, C, D and variant. In all strains except XPA, cells irradiated in plateau phase and subcultured immediately were much more resistant to the lethal effect of UV than cells irradiated in the exponential phase of growth. Typically, 10-20% of plateau-phase cells were extremely resistant. When the cultures were held in plateau phase for 24 h after irradiation and before subculture, there was a further enhancement of survival. By use of a UV-specific endonuclease assay, no difference was found in the number of DNA lesions induced in exponentially growing and plateau cultures by the same dose of UV light. Thus plateau-phase cells appear to be more efficient in their DNA-repair capability than cells in exponential growth. XP group A cells were uniquely found to be deficient in the processes which lead to plateau-phase resistance. Since plateau-phase repair was not lacking in XP groups C, D and variant, it may be related to a DNA-repair process different from that which is responsible for the overall UV sensitivity of these cells. (orig.)

Plateau's problem an invitation to varifold geometry

CERN Document Server

Frederick J Almgren, Jr

2001-01-01

There have been many wonderful developments in the theory of minimal surfaces and geometric measure theory in the past 25 to 30 years. Many of the researchers who have produced these excellent results were inspired by this little book--or by Fred Almgren himself. The book is indeed a delightful invitation to the world of variational geometry. A central topic is Plateau's Problem, which is concerned with surfaces that model the behavior of soap films. When trying to resolve the problem, however, one soon finds that smooth surfaces are insufficient: Varifolds are needed. With varifolds, one can obtain geometrically meaningful solutions without having to know in advance all their possible singularities. This new tool makes possible much exciting new analysis and many new results. Plateau's problem and varifolds live in the world of geometric measure theory, where differential geometry and measure theory combine to solve problems which have variational aspects. The author's hope in writing this book was to encour...

[Operative treatment for complex tibial plateau fractures].

Science.gov (United States)

Song, Qi-Zhi; Li, Tao

2012-03-01

To explore the surgical methods and clinical evaluation of complex tibial plateau fractures resulted from high-energy injuries. From March 2006 to May 2009,48 cases with complex tibial plateau fractures were treated with open reduction and plate fixation, including 37 males and 11 females, with an average age of 37 years (ranged from 18 to 63 years). According to Schatzker classification, 16 cases were type IV, 20 cases type V and 12 cases type VI. All patients were examined by X-ray flim and CT scan. The function of knee joint were evaluated according to postoperative follow-up X-ray and Knee Merchant Rating. Forty-eight patients were followed up with a mean time of 14 months. According to Knee Merchant Rating, 24 cases got excellent results, 16 cases good, 6 cases fair and 2 cases poor. Appropriate operation time, anatomical reduction, suitable bone graft and reasonable rehabilitation exercises can maximally recovery the function of knee joint.

Biogeography of cryoconite bacterial communities on glaciers of the Tibetan Plateau.

Science.gov (United States)

Liu, Yongqin; Vick-Majors, Trista J; Priscu, John C; Yao, Tandong; Kang, Shichang; Liu, Keshao; Cong, Ziyuang; Xiong, Jingbo; Li, Yang

2017-06-01

Cryoconite holes, water-filled pockets containing biological and mineralogical deposits that form on glacier surfaces, play important roles in glacier mass balance, glacial geochemistry and carbon cycling. The presence of cryoconite material decreases surface albedo and accelerates glacier mass loss, a problem of particular importance in the rapidly melting Tibetan Plateau. No studies have addressed the microbial community composition of cryoconite holes and their associated ecosystem processes on Tibetan glaciers. To further enhance our understanding of these glacial ecosystems on the Tibetan Plateau and to examine their role in carbon cycling as the glaciers respond to climate change, we explored the bacterial communities within cryoconite holes associated with three climatically distinct Tibetan Plateau glaciers using Illumina sequencing of the V4 region of the 16S rRNA gene. Cryoconite bacterial communities were dominated by Cyanobacteria, Chloroflexi, Betaproteobacteria, Bacteroidetes and Actinobacteria. Cryoconite bacterial community composition varied according to their geographical locations, exhibiting significant differences among glaciers studied. Regional beta diversity was driven by the interaction between geographic distance and environmental variables; the latter contributed more than geographic distance to the variation in cryoconite microbial communities. Our study is the first to describe the regional-scale spatial variability and to identify the factors that drive regional variability of cryoconite bacterial communities on the Tibetan Plateau. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Toward Quantitative Understanding of the Atmospheric Heating over the Tibetan Plateau (Invited)

Science.gov (United States)

Koike, T.; Tamura, T.; Rasmy, M.; Seto, R.

2010-12-01

There are different ideas on the atmospheric heating over the Tibetan Plateau. Yanai et al. (1992) and Yanai and Li (1994) concluded this sensible heat flux from the surface is the major source of heating on the plateau before the summer rain commences. On the other hand, Ueda et al. (2003) also showed the importance of condensation heating in the heat balance during the pre-onset-phase of the summer monsoon over the western part of the Tibetan Plateau. The first intensive in situ observation in early spring was implemented on the plateau in April 2004 under the framework of the Coordinated Enhanced Observing Period (CEOP) (Koike, 2004). Taniguchi and Koike (2007) revealed the importance of cumulus activity in atmospheric temperature increases in the upper troposphere even in April by in situ and satellite observations and numerical simulations. They concluded that sensible heat transfer by dry convection is insufficient to warm the upper layer over the plateau and that the development of cloud convection is indispensable for atmospheric heating in the upper troposphere over the plateau during early spring. Then, Taniguchi and Koike (2008) investigated the seasonal variation in the cloud activity over the eastern part of the Tibetan Plateau, and the vertical profile of the atmosphere and moist condition causing the cloud. They showed cumulus convections easily occur under the adiabatically neutral condition of the first phase of the active convections in April. During a resting phase before the second active phase, the atmosphere is conditionally unstable but an unsaturated condition restrains cloud activity, while during second phase, the atmosphere is inclined to be saturated and cloud activity begins again. From early May to mid June, there is a resting period of cumulus convective activity. However, the tropospheric temperature at 200 hPa increases rapidly from late April. Such rapid tropospheric warming without significant cumulus convective activity is

Deep mantle forces and the uplift of the Colorado Plateau

Energy Technology Data Exchange (ETDEWEB)

Moucha, R; Forte, A M; Rowley, D B; Mitrovica, J X; Simmons, N A; Grand, S P

2009-06-23

Since the advent of plate tectonics, it has been speculated that the northern extension of the East Pacific Rise, specifically its mantle source, has been over-ridden by the North American Plate in the last 30 Myrs. Consequently, it has also been postulated that the opening of the Gulf of California, the extension in the Basin and Range province, and the uplift of the Colorado Plateau are the resulting continental expressions of the over-ridden mantle source of the East Pacific Rise. However, only qualitative models based solely on surface observations and heuristic, simplified conceptions of mantle convection have been used in support or against this hypothesis. We introduce a quantitative model of mantle convection that reconstructs the detailed motion of a warm mantle upwelling over the last 30 Myrs and its relative advance towards the interior of the southwestern USA. The onset and evolution of the crustal uplift in the central Basin and Range province and the Colorado Plateau is determined by tracking the topographic swell due to this mantle upwelling through time. We show that (1) the extension and magmatism in the central Basin and Range province between 25 and 10 Ma coincides with the reconstructed past position of this focused upwelling, and (2) the southwestern portion of the Colorado Plateau experienced significant uplift between 10 Ma and 5 Ma that progressed towards the northeastern portion of the plateau. These uplift estimates are consistent with a young, ca. 6 Ma, Grand Canyon model and the recent commencement of mafic magmatism.

A Complex System of Glacial Sub-Refugia Drives Endemic Freshwater Biodiversity on the Tibetan Plateau.

Science.gov (United States)

Clewing, Catharina; Albrecht, Christian; Wilke, Thomas

2016-01-01

Although only relatively few freshwater invertebrate families are reported from the Tibetan Plateau, the degree of endemism may be high. Many endemic lineages occur within permafrost areas, raising questions about the existence of isolated intra-plateau glacial refugia. Moreover, if such refugia existed, it might be instructive to learn whether they were associated with lakes or with more dynamic ecosystems such as ponds, wetlands, or springs. To study these hypotheses, we used pulmonate snails of the plateau-wide distributed genus Radix as model group and the Lake Donggi Cona drainage system, located in the north-eastern part of the plateau, as model site. First, we performed plateau-wide phylogenetic analyses using mtDNA data to assess the overall relationships of Radix populations inhabiting the Lake Donggi Cona system for revealing refugial lineages. We then conducted regional phylogeographical analyses applying a combination of mtDNA and nuclear AFLP markers to infer the local structure and demographic history of the most abundant endemic Radix clade for identifying location and type of (sub-)refugia within the drainage system. Our phylogenetic analysis showed a high diversity of Radix lineages in the Lake Donggi Cona system. Subsequent phylogeographical analyses of the most abundant endemic clade indicated a habitat-related clustering of genotypes and several Late Pleistocene spatial/demographic expansion events. The most parsimonious explanation for these patterns would be a scenario of an intra-plateau glacial refugium in the Lake Donggi Cona drainage system, which might have consisted of isolated sub-refugia. Though the underlying processes remain unknown, an initial separation of lake and watershed populations could have been triggered by lake-level fluctuations before and during the Last Glacial Maximum. This study inferred the first intra-plateau refugium for freshwater animals on the Tibetan Plateau. It thus sheds new light on the evolutionary history

Spatial Variation in the Storages and Age-Related Dynamics of Forest Carbon Sequestration in Different Climate Zones—Evidence from Black Locust Plantations on the Loess Plateau of China

Science.gov (United States)

Li, Taijun; Ren, Bowen; Wang, Dahui; Liu, Guobin

2015-01-01

Knowledge about the long-term influences of climate change on the amount of potential carbon (C) sequestration in forest ecosystems, including age-related dynamics, remains unclear. This study used two similar age-sequences of black locust forests (Robinia pseudoacacia L.) in the semi-arid and semi-humid zones of China’s Loess Plateau to assess the variation in C stocks and age-related dynamics. Our results demonstrated that black locust forests of the semi-humid zone stored significantly more C than did forests in the semi-arid zone, across the chronosequence (p zone, while the semi-arid zone had a capacity of only 79.4 Mg C ha−1. Soil organic C (SOC) increased continuously with stand age in the semi-arid zone (R2 = 0.84, p = 0.010). However, in the semi-humid zone, SOC declined sharply by 47.8% after the initial stage (5 to 10 y). The C stock in trees increased continuously with stand age in the semi-humid zone (R2 = 0.83, p = 0.011), yet in the semi-arid zone, it decreased dramatically from 43.0 Mg C ha−1 to 28.4 Mg C ha−1 during the old forest stage (38 to 56 y). The shift from being a net C sink to a net C source occurred at the initial stage in the semi-humid zone versus at the old forest stage in the semi-arid zone after reforestation. Surprisingly, with the exception of the initial and later stages (55 y), the patterns of C allocation among trees, soils, understory and litter were not statistically different between the two climate zones. Our results suggest that climate factors can alter the potential amount and age-related dynamics of forest C sequestration. PMID:25799100

Late Quaternary strike-slip along the Taohuala Shan-Ayouqi fault zone and its tectonic implications in the Hexi Corridor and the southern Gobi Alashan, China

Science.gov (United States)

Yu, Jing-xing; Zheng, Wen-jun; Zhang, Pei-zhen; Lei, Qi-yun; Wang, Xu-long; Wang, Wei-tao; Li, Xin-nan; Zhang, Ning

2017-11-01

The Hexi Corridor and the southern Gobi Alashan are composed of discontinuous a set of active faults with various strikes and slip motions that are located to the north of the northern Tibetan Plateau. Despite growing understanding of the geometry and kinematics of these active faults, the late Quaternary deformation pattern in the Hexi Corridor and the southern Gobi Alashan remains controversial. The active E-W trending Taohuala Shan-Ayouqi fault zone is located in the southern Gobi Alashan. Study of the geometry and nature of slip along this fault zone holds crucial value for better understanding the regional deformation pattern. Field investigations combined with high-resolution imagery show that the Taohuala Shan fault and the E-W trending faults within the Ayouqi fault zone (F2 and F5) are left-lateral strike-slip faults, whereas the NW or WNW-trending faults within the Ayouqi fault zone (F1 and F3) are reverse faults. We collected Optically Stimulated Luminescence (OSL) and cosmogenic exposure age dating samples from offset alluvial fan surfaces, and estimated a vertical slip rate of 0.1-0.3 mm/yr, and a strike-slip rate of 0.14-0.93 mm/yr for the Taohuala Shan fault. Strata revealed in a trench excavated across the major fault (F5) in the Ayouqi fault zone and OSL dating results indicate that the most recent earthquake occurred between ca. 11.05 ± 0.52 ka and ca. 4.06 ± 0.29 ka. The geometry and kinematics of the Taohuala Shan-Ayouqi fault zone enable us to build a deformation pattern for the entire Hexi Corridor and the southern Gobi Alashan, which suggest that this region experiences northeastward oblique extrusion of the northern Tibetan Plateau. These left-lateral strike-slip faults in the region are driven by oblique compression but not associated with the northeastward extension of the Altyn Tagh fault.

Changes in effective moisture on the Tibetan Plateau during the period 1981-2010

Science.gov (United States)

Yin, Y.; Wu, S.; Zhao, D.

2013-12-01

Observed evaporative demand has decreased worldwide during the past several decades. This trend is also noted on the Tibetan Plateau, a region that is particularly sensitive to climate change. However, actual evapotranspiration trends and their relationship to drought stress on the Tibetan Plateau are poorly understood. We analyzed the spatiotemporal changes in potential evapotranspiration(PET), actual evapotranspiration(AET) and effective moisture (defined as AET/PET) during 1981-2010. Climate data from 80 meteorological stations on the Tibetan Plateau were compiled for the period 1981-2010. New plant functional types were defined for the Tibetan Plateau and evapotranspiration is simulated by the modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ). The results show regional trends towards decreasing PET and statistically significant increases in AET (p < 0.05) and effective moisture (p < 0.001) during the period 1981-2010. A transition from significant negative to positive PET occurred in 1997. Additionally, a pronounced increase in effective moisture occurred during the period 1981-1997 because of significant decreased PET before 1997.

Challenges for Deep Vadose Zone Remediation at the Hanford Site

International Nuclear Information System (INIS)

Morse, John G.; Charboneau, Briant L.; Lober, Robert W.; Triplett, Mark B.

2008-01-01

The 'deep vadose zone' is defined as the region below the practical depth of surface remedy influence (e.g., excavation or barrier). At the Hanford Site, this region of the Central Plateau poses unique challenges for characterization and remediation. The contaminants in this region also pose a potentially significant continuing or future threat to groundwater. Currently, deep vadose zone characterization efforts and remedy selection are spread over multiple waste site Operable Units and tank farm Waste Management Areas. A particular challenge for this effort is the situation in which past leaks from single-shell tanks have become commingled with discharges from nearby liquid disposal sites. The Hanford Site is working with all affected parties, including the Washington State Department of Ecology, the Environmental Protection Agency, DOE-RL, DOE-ORP, and multiple contractor organizations to develop a unified approach to conducting work and reaching remediation decisions. This effort addresses the complex and challenging technical and regulatory issues within this environment. A true inter-Agency effort is evaluating the best strategy or combination of strategies for focusing technical investigations, including treatability studies, and for attaining remedy decisions on the Hanford Site

Integration of ground-water and vadose-zone geochemistry to investigate hydrochemical evolution

International Nuclear Information System (INIS)

Fisher, R.S.; Mullican, W.F.

1990-01-01

This paper summarizes the results of an extensive groundwater-sampling program conducted in the Hueco Bolson and Diablo Plateau area of West Texas. The origin, hydrochemical evolution, and age of groundwater in arid lands of Trans-Pecos Texas were investigated by combining mineralogic analyses of soils and aquifer matrix, chemical analyses of readily soluble materials in soils and water extracted from the thick, unsaturated zone, and chemical and isotopic analyses of groundwater from three principal aquifers, the Diablo Plateau, Hueco Bolson, and Rio Grande alluvial aquifers. Repeated groundwater sampling over a 3-year period and quarterly sampling of selected wells revealed no significant short-term chemical or isotopic variability. Groundwater ages range from recent to nearly 28,000 years; the distribution of ages reflects relative permeability (transmissivity) of the aquifers. Most groundwaters evolve from calcium-bicarbonate to sodium-sulfate types because of carbonate and sulfate mineral dissolution coupled with exchange of aqueous calcium and magnesium for sodium on clay minerals. Water in the Rio Grande alluvial aquifer evolved to a sodium-chloride type as a result of extensive evapotranspiration on irrigated fields. The appendices list detailed results of field measurements of temperature, pH, Eh, dissolved oxygen, and major ion concentrations

Coseismic Strain Steps of the 2008 Wenchuan Earthquake Indicate EW Extension of Tibetan Plateau and Increased Hazard South to Epicenter

Science.gov (United States)

Fu, G.; Shen, X.; Tang, J.; Fukuda, Y.

2008-12-01

The 2008 Wenchuan earthquake (Ms8.0) occurred at the east edge of Tibetan Plateau. It is the biggest seismic disaster in China since the 1976 Tangshan earthquake. To determine the effects of the earthquake on the deformation field of Tibetan Plateau, we collect and analyze continuing strain data of three stations before and after the earthquake in Tibetan Plateau observed by capacitance-type bore-hole strainmeters (Chi, 1985). We collect strain data in NS, EW, NE-SW and NW-NS directions at each borehole. Then we deduce the co-seismic strain steps at time point 14:28 of May 12, 2008 (at this time point the earthquake occurred) with the data before and after the earthquake using the least squares method. Our observation shows that in Tibetan Plateau significant co-seismic strain steps are accompanied with the 2008 Wenchuan earthquake. Extension in EW direction is observed at interior and north Tibetan Plateau which indicates a rapid EW extension of the whole Plateau. Field investigation shows that the 2008 Wenchuan earthquake is a manifestation of eastward growth of the Tibetan Plateau (Dong et al., 2008). Eastwards growth of the Tibetan Plateau results naturally in the extension of the Plateau in EW direction. Our co-seismic strain observation agrees well with the conclusion from surface rupture investigation. The magnitude of co-seismic strain step equals to five times of average year extensional strain rate throughout the plateau interior. Shortening in SE- NW direction is observed at the east edge of the Plateau. As hints that the eastward extension of Tibetan Plateau is resisted by Sichuan rigid basin which increases the potential earthquake hazard around the observation station, manifests the declaration from co-seismic stress changes calculation (Persons et al., 2008). Our observed co-seismic strain steps are in total lager than theoretical calculations of dislocation theories which indicate that magnitude of the great earthquake should be bigger than 7.9. Due

Changes in Biomass and Quality of Alpine Steppe in Response to N & P Fertilization in the Tibetan Plateau

Science.gov (United States)

Dong, Junfu; Cui, Xiaoyong; Wang, Shuping; Wang, Fang; Pang, Zhe; Xu, Ning; Zhao, Guoqiang; Wang, Shiping

2016-01-01

In the alpine steppe zone on the Central Tibetan Plateau, a large amount of area has been degraded due to natural and artificial factors. N & P fertilization is widely accepted to recover degraded pastures in other regions all over the world. However, it is not clear how alpine steppe communities respond to N & P fertilization, and what is the optimal application rate, in the perspective of forage production. To attempt to explore these questions, in July 2013, two fencing sites were designed in Baingoin County with 12 treatments of different levels of nitrogen (N0: 0; N1: 7.5 g m-2 yr-1; N2: 15 g m-2 yr-1) & phosphate (P0: 0; P1: 7.5 gP2O5 m-2 yr-1; P2: 15 gP2O5 m-2 yr-1; P3: 30 gP2O5 m-2 yr-1). The results indicated N&P addition was capable to ameliorate the quality of the two sites in the Tibetan Plateau steppe. Increasing N application level resulted in significant increment in Gramineae and total biomass in the two sites. P addition significantly improved the quantity of Compositae, total biomass and the biomasss of other species in site II, while it only significantly improved the total biomass in site I. Gramineae was much more sensitive to N-induced changes than P-induced changes, and this indicated N addition was better to ameliorate the quality of plateau steppe than P-induced changes. No strong evidence was found for critical threshold within 15 g N m-2 yr-1, and there was decreasing tendency when P addition rate was above 15 g m-2 yr-1. N&P has the potential to accelerate soil acidification, which improved the content of available K, likely as a result of nonsignificant correlation between biomass and soil moisture. This work highlights the the tradeoffs that exist in N and P addition in recovering degraded steppe. PMID:27223104

Linkages between orogenic plateau build-up, fold-thrust shortening, and foreland basin evolution in the Zagros (NW Iran)

Science.gov (United States)

Barber, D. E.; Stockli, D. F.

2017-12-01

The Iranian Plateau (IP) is a thickened, low-relief morphotectonic province of diffuse deformation that formed due to Arabia-Eurasia collision and may serve as a younger analogue for the Tibetan Plateau. Despite detailed geophysical characterization of the IP, its deformation history and relationship to the Zagros fold-thrust belt and its foreland basin evolution remains unresolved. Low-temperature thermochronometry and provenance data from a transect across the internal and external Zagros track growth of the IP and delineate multiphase interaction between upper- and lower-plate processes during closure of the Neotethys and Arabia-Eurasia suturing. Inversion of zircon (U-Th)/He and fission-track data from plutonic and metamorphic basement rocks in the Sanandaj-Sirjan Zone (SSZ) of the IP reveals an initial stage of low-rate exhumation from 36-25 Ma, simultaneous with the onset of tectonic subsidence and marine incursion in the Zagros foreland basin. Overlapping apatite fission-track and (U-Th)/He ages indicate sharp acceleration in SSZ exhumation rates between 20-15 Ma, coincident with rejuvenation of foreland basin subsidence and an influx of Eurasian-derived sediments into the Zagros foreland deposited above an Oligocene unconformity. The mid-Miocene marks a transition in focused exhumation from the SSZ to Arabian lower-plate. Apatite (U-Th)/He ages suggest in-sequence fold-thrust propagation from the High Zagros to simply folded belt from 10 Ma to recent, which is reflected in the foreland by a shift in provenance to dominantly recycled Arabian-derived detritus and clastic facies progradation. Integrated thermochronometric and provenance data document a two-phase outward expansion of the Iranian Plateau and Zagros fold-thrust belt, tightly coupled to distinct phases of basin evolution and provenance shifts in the Zagros foreland. We associate multiple deformation and basin episodes with protracted collisional processes, from subduction of attenuated Arabian

Mixing on the Heard Island Plateau during HEOBI

Science.gov (United States)

Robertson, R.

2016-12-01

On the plateau near Heard and McDonald Islands, the water column was nearly always well mixed. Typically, temperature differences between the surface and the bottom, 100-200 m, were less than 0.2oC and often less that 0.1oC. Surface stratification developed through insolation and deep primarily through a combination of upwelling from canyons and over the edge of the plateau and tidal advection. This stratification was primarily removed by a combination of wind and tidal mixing. Persistent winds of 30 knots mixed the upper 20-50 m. Strong wind events, 40-60 knots, mixed the water column to 100-200 m depth, which over the plateau, was often the entire water column. Benthic tidal friction mixed the bottom 30-50 m. Although the water column was unstratified at the two plume sites intensively investigated, tidal velocities were baroclinic, probably due to topographic controls. Tidal advection changed the bottom temperatures by 0.5oC within 8 hours, more than doubling the prior stratification. Wind mixing quickly homogenized the water column, resulting in the surface often showing the deeper upwelling and advective events. Although acoustic plumes with bubbles were observed in the water column, there was no evidence of geothermal vents or geothermal influence on temperatures. Mixing by bubbles rising in the water column was indistinguishable from the wind and tidal mixing, although the strongest upward vertical velocities were observed at the sites of these acoustic/bubble plumes.

Cyprininae phylogeny revealed independent origins of the Tibetan Plateau endemic polyploid cyprinids and their diversifications related to the Neogene uplift of the plateau.

Science.gov (United States)

Wang, Xuzhen; Gan, Xiaoni; Li, Junbing; Chen, Yiyu; He, Shunping

2016-11-01

Origin and diversification of the Tibetan polyploid cyprinids (schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that (i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins; (ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.

The Colorado Plateau III: integrating research and resources management for effective conservation

Science.gov (United States)

Sogge, Mark K.; van Riper, Charles

2008-01-01

Roughly centered on the Four Corners region of the southwestern United States, the Colorado Plateau covers an area of 130,000 square miles. The relatively high semi-arid province boasts nine national parks, sixteen national monuments, many state parks, and dozens of wilderness areas. With the highest concentration of parklands in North America and unique geological and ecological features, the area is of particular interest to researchers. Derived from the Eighth Biennial Conference of Research on the Colorado Plateau, this third volume in a series of research on the Colorado Plateau expands upon the previous two books. This volume focuses on the integration of science into resource management issues, summarizes what criteria make a successful collaborative effort, outlines land management concerns about drought, provides summaries of current biological, sociological, and archaeological research, and highlights current environmental issues in the Four Corner States of Arizona, New Mexico, Colorado, and Utah. With broad coverage that touches on topics as diverse as historical aspects of pronghorn antelope movement patterns through calculating watershed prescriptions to the role of wind-blown sand in preserving archaeological sites on the Colorado River, this volume stands as a compendium of cuttingedge management-oriented research on the Colorado Plateau. The book also introduces, for the first time, tools that can be used to assist with collaboration efforts among landowners and managers who wish to work together toward preserving resources on the Colorado Plateau and offers a wealth of insights into land management questions for many readers, especially people interested in the natural history, biology, anthropology, wildlife, and cultural management issues of the region.

Spatial and temporal variation of tectonic uplift in the southeastern Ethiopian Plateau from morphotectonic analysis

Science.gov (United States)

Xue, Liang; Alemu, Tadesse; Gani, Nahid D.; Abdelsalam, Mohamed G.

2018-05-01

We use morphotectonic analysis to study the tectonic uplift history of the southeastern Ethiopian Plateau (SEEP). Based on studies conducted on the Northwestern Ethiopian Plateau, steady-state and pulsed tectonic uplift models were proposed to explain the growth of the plateau since 30 Ma. We test these two models for the largely unknown SEEP. We present the first quantitative morphotectonic study of the SEEP. First, in order to infer the spatial distribution of the tectonic uplift rates, we extract geomorphic proxies including normalized steepness index ksn, hypsometric integral HI, and chi integral χ from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model (DEM). Second, we compare these rates with the thickness of flood basalt that we estimated from geological maps. Third, to constrain the timing of regional tectonic uplift, we develop a knickpoint celerity model. Fourth, we compare our results to those from the Northwestern Ethiopian Plateau to suggest a possible mechanism to explain regional tectonic uplift of the entire Ethiopian Plateau. We find an increase in tectonic uplift rates from the southeastern escarpments of the Afar Depression in the northeast to that of the Main Ethiopian Rift to the southwest. We identify three regional tectonic uplift events at 11.7, 6.5, and 4.5 Ma recorded by the development of regionally distributed knickpoints. This is in good agreement with ages of tectonic uplift events reported from the Northwestern Ethiopian Plateau.

Double hump sign in indentation gonioscopy is correlated with presence of plateau iris configuration regardless of patent iridotomy.

Science.gov (United States)

Kiuchi, Yoshiaki; Kanamoto, Takashi; Nakamura, Takao

2009-02-01

A plateau iris is one of the clinical forms of angle closure glaucoma. In patients with a patent iridotomy, the double hump sign detected during indentation gonioscopy has been reported to indicate the existence of a plateau iris configuration. The purpose of this study was to determine whether the double hump sign is correlated with the presence of the plateau iris syndrome regardless of the patency of the iridotomy. Five women and 3 men without a patent iridotomy presented with narrow angles on gonioscopy and a double hump sign on indentation gonioscopy. Ultrasound biomicroscopy (UBM) imaging was performed to determine the etiology of the narrow angle and double hump sign, and to determine the appropriate treatment to prevent the progression of visual field damage. Ten patients with narrow angles and without a double hump sign were also examined by UBM to serve as a control group. All 8 patients who showed double hump sign had a short iris root, which was inserted anterior to the ciliary face, a typical anatomic appearance of a plateau iris. On the other hand, only 1 eye of 10 eyes in control group appeared to have a plateau iris. A double hump sign observed on indentation gonioscopy is strongly correlated with the presence of a plateau iris, and therefore a useful indicator of a plateau iris configuration regardless of the patency of a laser iridotomy. Thus, a plateau iris configuration can be detected without using a UBM in many cases.

Deep Vadose Zone Applied Field Research Center: Transformational Technology Development For Environmental Remediation

International Nuclear Information System (INIS)

Wellman, Dawn M.; Triplett, Mark B.; Freshley, Mark D.; Truex, Michael J.; Gephart, Roy E.; Johnson, Timothy C.; Chronister, Glen B.; Gerdes, Kurt D.; Chamberlain, Skip; Marble, Justin; Ramirez, Rosa

2011-01-01

DOE-EM, Office of Groundwater and Soil Remediation and DOE Richland, in collaboration with the Hanford site and Pacific Northwest National Laboratory, have established the Deep Vadose Zone Applied Field Research Center (DVZ-AFRC). The DVZ-AFRC leverages DOE investments in basic science from the Office of Science, applied research from DOE EM Office of Technology Innovation and Development, and site operation (e.g., site contractors [CH2M HILL Plateau Remediation Contractor and Washington River Protection Solutions], DOE-EM RL and ORP) in a collaborative effort to address the complex region of the deep vadose zone. Although the aim, goal, motivation, and contractual obligation of each organization is different, the integration of these activities into the framework of the DVZ-AFRC brings the resources and creativity of many to provide sites with viable alternative remedial strategies to current baseline approaches for persistent contaminants and deep vadose zone contamination. This cooperative strategy removes stove pipes, prevents duplication of efforts, maximizes resources, and facilitates development of the scientific foundation needed to make sound and defensible remedial decisions that will successfully meet the target cleanup goals for one of DOE EM's most intractable problems, in a manner that is acceptable by regulators.

Cenozoic Uplift and Climate Change of the Northeast Tibetan Plateau: Evidence from Leaf Wax Stable Isotopic Records

Science.gov (United States)

Hou, M.; Zhuang, G.; Wu, M.

2017-12-01

Topics about the deformation history and uplift mechanism of Tibetan Plateau have been largely debated in the past few decades. Different geodynamic models present different predictions on the mountain building processes and hence the surface uplift history. For example, one tectonic model suggests a rapid uplift (>1.0 to 2.0 km) of the Tibetan Plateau in the period of ca. 10 to 8 Ma as result of isostatic rebound due to the removal of over-thickened mental lithosphere beneath. Whilst the stepwise uplift model infers that the high topography was growing progressively from south to north with the Northeast Tibetan Plateau being built in the Pliocene to present. In this case, the timing of Cenozoic uplift of Northeast Tibetan Plateau would provide information for distinguishing competing geodynamic processes. The stable isotope based paleoaltimetry holds the key to answering when the high topography was built. Additionally, the evolution of Cenozoic Asian climate was argued to be closely related to the high topography built up on the Tibetan Plateau since the India-Asian collision and/or impacted by the global change. To understand when the high topography was built and how the growth of Tibetan Plateau impacted the climate, we reconstructed the long-term histories of paleohydrology from hinterland and foreland basins in the Northeast Tibetan Plateau. We applied the compound-specific isotope hydrogen analysis to leaf wax n-alkanes (δ2Hn-alk) that are preserved in well-dated stratigraphic series (ca. 24 Ma to the present) in the Northeast Tibetan Plateau. The newly reconstructed δ2Hn-alk supports the inference of high topography on the Northeast Tibetan Plateau was built during the middle to late Miocene. Our inference is consistent with sedimentary and basement rock studies that show fundamental changes in facies and provenance and exhumation history. The new δ2Hn-alk record also reveals that the regional climate became drier since the middle Miocene following the

Late summer distribution and stoichiometry of dissolved N, Si and P in the Southern Ocean near Heard and McDonald Islands on the Kerguelen Plateau

Science.gov (United States)

Chase, Z.; Bowie, A. R.; Blain, S.; Holmes, T.; Rayner, M.; Sherrin, K.; Tonnard, M.; Trull, T. W.

2016-12-01

The Kerguelen plateau in the Southern Indian Ocean is a naturally iron-fertilised region surrounded by iron-limited, High Nutrient Low Chlorophyll waters. The Heard Earth Ocean Biosphere Interaction (HEOBI) project sampled waters south of the Polar Front in the vicinity of Heard and McDonald Islands (HIMI) in January and February 2016. Fe fertilised waters over the plateau generally exhibited high phytoplankton biomass and photosynthetic competency (as in previous studies and satellite observations), but interestingly, phytoplankton biomass was low near HIMI, though photosynthetic competency was high. In plateau waters away from HIMI, silicic acid (Si) concentrations were strongly depleted in surface waters, averaging 3 μM, while nitrate concentrations were close to 25 μM. Relative to the remnant winter water, this represents an average seasonal drawdown of 32 μM Si and only 8 μM nitrate. Though absolute drawdown was lower at an HNLC reference site south of Heard Island, the drawdown ratio was similarly high (ΔSi: ΔN 4-5). The average N:P drawdown ratio was 12, typical for a diatom-dominated system (Weber and Deutsch 2010). N:P drawdown was positively correlated with Si drawdown, perhaps indicative of an impact of Fe on both seasonal Si drawdown and diatom N:P uptake (Price 2005). In the well-mixed, shallow waters (McDonald Islands, despite the apparent lack of nutrient drawdown or biomass accumulation. Mixed layers deeper than the euphotic zone are one mechanism that retains these remineralization signatures and near the islands, tidal mixing also contributes.

FINAL FRONTIER AT HANFORD TACKLING THE CENTRAL PLATEAU

International Nuclear Information System (INIS)

GERBER MS

2008-01-01

The large land area in the center of the vast Department of Energy (DOE) Hanford Site in southeast Washington State is known as 'the plateau'--aptly named because its surface elevations are 250-300 feet above the groundwater table. By contrast, areas on the 585-square mile Site that border the Columbia River sit just 30-80 feet above the water table. The Central Plateau, which covers an ellipse of approximately 70 square miles, contains Hanford's radiochemical reprocessing areas--the 200 East and 200 West Areas--and includes the most highly radioactive waste and contaminated facilities on the Site. Five 'canyons' where chemical processes were used to separate out plutonium (Pu), 884 identified soil waste sites (including approximately 50 miles of solid waste burial trenches), more than 900 structures, and all of Hanford's liquid waste storage tanks reside in the Central Plateau. (Notes: Canyons is a nickname given by Hanford workers to the chemical reprocessing facilities. The 177, underground waste tanks at Hanford comprise a separate work scope and are not under Fluor's management). Fluor Hanford, a DOE prime cleanup contractor at the Site for the past 12 years, has moved aggressively to investigate Central Plateau waste sites in the last few years, digging more than 500 boreholes, test pits, direct soil 'pushes' or drive points; logging geophysical data sets; and performing electrical-resistivity scans (a non-intrusive technique that maps patterns of sub-surface soil conductivity). The goal is to identify areas of contamination areas in soil and solid waste sites, so that cost-effective and appropriate decisions on remediation can be made. In 2007, Fluor developed a new work plan for DOE that added 238 soil waste-site characterization activities in the Central Plateau during fiscal years (FYs) 2007-2010. This number represents a 50 percent increase over similar work previously done in central Hanford. Work Plans are among the required steps in the Comprehensive

Estimates of grassland biomass and turnover time on the Tibetan Plateau

Science.gov (United States)

Xia, Jiangzhou; Ma, Minna; Liang, Tiangang; Wu, Chaoyang; Yang, Yuanhe; Zhang, Li; Zhang, Yangjian; Yuan, Wenping

2018-01-01

The grassland of the Tibetan Plateau forms a globally significant biome, which represents 6% of the world’s grasslands and 44% of China’s grasslands. However, large uncertainties remain concerning the vegetation carbon storage and turnover time in this biome. In this study, we quantified the pool size of both the aboveground and belowground biomass and turnover time of belowground biomass across the Tibetan Plateau by combining systematic measurements taken from a substantial number of surveys (i.e. 1689 sites for aboveground biomass, 174 sites for belowground biomass) with a machine learning technique (i.e. random forest, RF). Our study demonstrated that the RF model is effective tool for upscaling local biomass observations to the regional scale, and for producing continuous biomass estimates of the Tibetan Plateau. On average, the models estimated 46.57 Tg (1 Tg = 1012g) C of aboveground biomass and 363.71 Tg C of belowground biomass in the Tibetan grasslands covering an area of 1.32 × 106 km2. The turnover time of belowground biomass demonstrated large spatial heterogeneity, with a median turnover time of 4.25 years. Our results also demonstrated large differences in the biomass simulations among the major ecosystem models used for the Tibetan Plateau, largely because of inadequate model parameterization and validation. This study provides a spatially continuous measure of vegetation carbon storage and turnover time, and provides useful information for advancing ecosystem models and improving their performance.

Decreased surface albedo driven by denser vegetation on the Tibetan Plateau

International Nuclear Information System (INIS)

Tian, Li; Zhang, Yangjian; Zhu, Juntao

2014-01-01

The Tibetan Plateau (TP) has fundamental ecological and environmental significance to China and Asia through its influence on regional and continental climates. In recent years, climate warming has caused unprecedented changes to land surface processes on the TP, which would unavoidably undermine the ecological and environmental functions of the TP. Among the numerous land surface processes potentially impacted by climate warming, the effect of vegetation greenness on surface energy balance is one of the most critical, but has been long ignored. In this study, we investigated the spatial and temporal patterns of land surface albedo (LSA) on the TP and evaluated the vegetation greenness in relation to patterns of LSA. We found that LSA has been decreasing in most of the vegetated grasslands on the TP from 2000 to 2013, as compared to a flat trend for desert area. The regions where LSA has been decreasing were spatially correlated to areas of increased vegetation greenness. Along rising altitude, LSA decreasing rate exhibited an overall decreasing trend. Across the TP, elevated vegetation greenness in grasslands acted as a primary factor pulling down LSA. The driving effects of vegetation greenness on LSA vary with grassland types, as revealed by a more significant relationship between vegetation greenness and LSA for the sparsely vegetated zone (i.e. steppe) than the more densely vegetated zone (i.e. meadow). Furthermore, the driving effect of vegetation greenness on LSA exhibited an obvious dependence on altitude as effects with rising altitude were relatively strong up to 3000 m, then weakened from 3500 m to 5000 m, and then the effects again increased from 5000 to 6000 m. The growing season LSA trend revealed in this study emphasizes the need to give greater attention to the growing season LSA flux in future surface energy balance studies. (letter)

Allopatric divergence of Stuckenia filiformis (Potamogetonaceae) on the Qinghai-Tibet Plateau and its comparative phylogeography with S. pectinata in China.

Science.gov (United States)

Du, Zhi-Yuan; Wang, Qing-Feng

2016-02-11

In the aquatic genus Stuckenia, the wide geographic range of S. pectinata and S. filiformis make them suited for examination of topographic and climatic effects on plant evolution. Using nuclear ITS sequence and ten chloroplast sequences, we conducted comparative phylogeographical analyses to investigate their distribution regions and hybrid zones in China, and compare their phylogeographical patterns and demographical histories. These two species were allopatric in China. S. filiformis occurred only on the Qinghai-Tibet Plateau (QTP), whereas S. pectinata occupied a wide range of habitats. These two species formed hybrid zones on the northeastern edge of QTP. Most of the genetic variance of S. filiformis was between the southern and eastern groups on the QTP, showing a significant phylogeographic structure. The geographical isolations caused by the Nyenchen Tanglha Mountains and the Tanggula Mountains promoted intraspecific diversification of alpine plants on the QTP. This study revealed the lack of phylogeographic structure in S. pectinata, due to the continued gene flow among its distribution regions. The ecological niche modeling showed that the distribution ranges of these two herbaceous species did not contract too much during the glacial period.

Iceberg incursions across Campbell Plateau

International Nuclear Information System (INIS)

Northcote, L.; Neil, H.; Carter, L.

1999-01-01

The last reported sighting of icebergs off eastern New Zealand was on 28th October, 1892, at the Chatham Islands. Prior to that time, the SW Pacific Ocean periodically hosted flotillas of icebergs, as revealed by a palaeoceanographic analysis of 8 cores from the Campbell Plateau. Stable isotope stratigraphy, coupled with down-core measurements of magnetic susceptibility, grain size, calcium carbonate and ice-rafted debris, highlight climate-related fluctuations in iceberg activity back to at least marine isotope stage (MIS) 6 - our longest complete record. (author)

The plateau zokors' learning and memory ability is related to the high expression levels of foxP2 in the brain.

Science.gov (United States)

Ma, Ben-Yuan; Wei, Lian; Sun, Sheng-Zhen; Wang, Duo-Wei; Wei, Deng-Bang

2014-04-25

Plateau zokor (Myospalax baileyi) is a subterranean mammal. Plateau zokor has high learning and memory ability, and can determine the location of blocking obstacles in their tunnels. Forkhead box p2 (FOXP2) is a transcription factor implicated in the neural control of orofacial coordination and sensory-motor integration, particularly with respect to learning, memory and vocalization. To explore the association of foxP2 with the high learning and memory ability of plateau zokor, the cDNA of foxP2 of plateau zokor was sequenced; by using plateau pika as control, the expression levels of foxP2 mRNA and FOXP2 protein in brain of plateau zokor were determined by real-time PCR and Western blot, respectively; and the location of FOXP2 protein in the brain of plateau zokor was determined by immunohistochemistry. The result showed that the cDNA sequence of plateau zokor foxP2 was similar to that of other mammals and the amino acid sequences showed a relatively high degree of conservation, with the exception of two particular amino acid substitutions [a Gln (Q)-to-His (H) change at position 231 and a Ser (S)-to-Ile (I) change at position 235]. Higher expression levels of foxP2 mRNA (3-fold higher) and FOXP2 protein (>2-fold higher) were detected in plateau zokor brain relative to plateau pika brain. In plateau zokor brain, FOXP2 protein was highly expressed in the cerebral cortex, thalamus and the striatum (a basal ganglia brain region). The results suggest that the high learning and memory ability of plateau zokor is related to the high expression levels of foxP2 in the brain.

Internal tides and vertical mixing over the Kerguelen Plateau

Science.gov (United States)

Park, Young-Hyang; Fuda, Jean-Luc; Durand, Isabelle; Naveira Garabato, Alberto C.

2008-03-01

Within the context of the natural iron-fertilization study KEOPS, time series measurements of CTD and LADCP profiles at a site (50.6°S, 72°E; 528 m) coinciding with an annual phytoplankton bloom over the Kerguelen Plateau were made during the January-February 2005 KEOPS cruise. An important activity of highly nonlinear semidiurnal internal tides having peak-to-peak isopycnal displacements of up to 80 m is identified. These internal tides appear to be a principal agent for promoting elevated vertical mixing indispensable for upward transfer of iron within the seasonal thermocline. We estimate local vertical eddy diffusivities of the order of 4×10 -4 m 2 s -1 using a Thorpe scale analysis. Although this estimate is higher by an order of magnitude than the canonical value O (0.1×10 -4 m 2 s -1) in the open ocean away from boundaries, it is consistent with nonlinear internal wave/wave interaction theories, as verified by independent diffusivity estimates using the vertical wavenumber spectral methods for shear and strain. It is also suggested that the general ocean circulation may play an important role in preconditioning the bloom in that the relatively sluggish circulation over the shallow plateau (compared to the much more dynamic neighbouring deep ocean) may foster the bloom's observed annual recurrence over the plateau.

Genetic variation and phylogenetic relationships of the ectomycorrhizal Floccularia luteovirens on the Qinghai-Tibet Plateau.

Science.gov (United States)

Xing, Rui; Gao, Qing-Bo; Zhang, Fa-Qi; Fu, Peng-Cheng; Wang, Jiu-Li; Yan, Hui-Ying; Chen, Shi-Long

2017-08-01

Floccularia luteovirens, as an ectomycorrhizal fungus, is widely distributed in the Qinghai-Tibet Plateau. As an edible fungus, it is famous for its unique flavor. Former studies mainly focus on the chemical composition and genetic structure of this species. However, the phylogenetic relationship between genotypes remains unknown. In this study, the genetic variation and phylogenetic relationship between the genotypes of F. luteovirens in Qinghai-Tibet Plateau was estimated through the analysis on two protein-coding genes (rpb1 and ef-1α) from 398 individuals collected from 24 wild populations. The sample covered the entire range of this species during all the growth seasons from 2011 to 2015. 13 genotypes were detected and moderate genetic diversity was revealed. Based on the results of network analysis, the maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) analyses, the genotypes H-1, H-4, H-6, H-8, H-10, and H-11 were grouped into one clade. Additionally, a relatively higher genotype diversity (average h value is 0.722) and unique genotypes in the northeast edge of Qinghai- Tibet plateau have been found, combined with the results of mismatch analysis and neutrality tests indicated that Southeast Qinghai-Tibet plateau was a refuge for F. luteovirens during the historical geological or climatic events (uplifting of the Qinghai-Tibet Plateau or Last Glacial Maximum). Furthermore, the present distribution of the species on the Qinghai-Tibet plateau has resulted from the recent population expansion. Our findings provide a foundation for the future study of the evolutionary history and the speciation of this species.

Geometry and Kinematics of the Lopukangri Fault System: Implications for Internal Deformation of the Tibetan Plateau

Science.gov (United States)

Murphy, M. A.; Taylor, M. H.

2006-12-01

We present geologic mapping and structural data from the Lopukangri fault system in south-central Tibet that sheds light on the geometry, kinematics and spatial characteristics of deformation in western Tibet and the western Himalaya. The Lopukangri fault system strikes N09E and extends 150 km from the Lhasa terrane into the Tethyan fold-thrust belt at 84.5° N. Geologic mapping shows that the deformation is accommodated by a northwest dipping oblique fault system, which accommodates both right-lateral and normal dip-slip movement, consistent with right-lateral separations of Quaternary surficial deposits. The fault system juxtaposes amphibolite-grade rocks in its footwall against greenschist-grade rocks in its hanging wall. Deformation is distributed over a 4 km wide zone that predominately records right-lateral normal slip in ductile and brittle shear fabrics. The fault system right-laterally separates the Gangdese batholith, Kailas conglomerate, Great Counter thrust, and the Tethyan fold-thrust belt for 15 km. Age estimates of the Kailas conglomerate in the Kailas region implies that the Lopukangri fault system initiated after the Early Miocene( 23Ma). The observation that the Lopukangri fault system cuts the Indus-Yaly suture zone, rules out active strike-slip faulting along it at this locality. To assess the role of the Lopukangri fault system in accommodating strain within western Tibet, we compare our results with fault-slip data and structural geometries from the Karakoram and Dangardzong (Thakkhola graben) fault systems. The Dangardzong fault shares similar kinematics with the Lopukangri fault system, both display a significant component of right-slip. Although the two faults do not strike into one another, they may be linked via a transfer zone. The Karakoram fault accommodates right-lateral slip in which a portion of the total slip extends from the Tibetan plateau into the Himalayan thrust belt via right-stepover structures. Fault slip data from the

Plateau diffusion coefficient for arbitrary flux surface geometry

International Nuclear Information System (INIS)

Meier, H.K.; Hirshman, S.P.; Sigmar, D.J.; Lao, L.L.

1981-03-01

A relatively simple but accurate representation has been developed for magnetic flux surfaces; it is valid for finite β and it describes configurations with both ellipticity and D-shape. This representation has been applied to the computation of the diffusion coefficient in the plateau regime

Neoclassical kinetic theory near an X point: Plateau regime

International Nuclear Information System (INIS)

Solano, E.R.; Hazeltine, R.D.

1994-01-01

Traditionally, neoclassical transport calculations ignore poloidal variation of the poloidal magnetic field. Near an X point of the confining field of a diverted plasma, the poloidal field is small, causing guiding centers to linger at that poloidal position. A study of how neoclassical transport is affected by this differential shaping is presented. The problem is solved in general in the plateau regime, and a model poloidal flux function with an X point is utilized as an analytic example to show that the plateau diffusion coefficient can change considerably (factor of 2 reduction). Ion poloidal rotation is proportional to the local value of B pol but otherwise it is not strongly affected by shaping. The usual favorable scaling of neoclassical confinement time with plasma current is unaffected by the X point

[Dynamic changes of Ruoergai Plateau wetland ecosystem service value].

Science.gov (United States)

Zhang, Xiao-Yun; Lü, Xian-Guo; Shen, Song-Ping

2009-05-01

Based on the satellite remote sensing data acquired in 1975 and 2006, and by using the assessment method of ecosystem service value, the dynamic changes of physical production value, gas regulation value, and water storage value of Ruoergai Plateau wetland ecosystem in 1975-2006 were studied. During study period, the total value of the three services decreased from 19.59 billion RMB Yuan to 12.38 billion Yuan RMB, among which, physical production value increased by 0.302 billion RMB Yuan, while the gas regulation and water storage value decreased by 7.507 billion RMB Yuan. The benefit from the increase of physical production was much less than the loss of ecosystem degradation. Overgrazing induced the biomass reduction and soil deterioration, resulting in the decline of Ruoergai Plateau wetland ecosystem service value and service capacity.

Geomorphological investigations and GIS approach of the Tamiš loess plateau, Banat region (northern Serbia

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Popov Dragan

2012-01-01

Full Text Available The focus of this study was the loess plateau located in the Tamiš River valley in the central part of Banat region (northern Serbia. This morphologic unit has been formed by the loess accumulation process during the last two glacial periods. Digital elevation model (DEM is based on the 1:25.000 scale topographic maps. Detailed geomorphologic and hypsometric maps are provided with selected cross sections. The borders of the plateau and spatial distribution of the micromorphology are precisely defined on DEM. The plateau rises gradually from the Upper Pleistocene terrace on the north and northwest, while to the east and south slopes and vertical bluffs were controlled by the lateral erosion process of surrounding channels and by the weathering process on the loess. The plateau has an atypical morphology characterized by reduced geomorphologic diversity. Loess topography is significantly flattened by human impact. Its micromorphology is characterised by shallow depressions and gullies.

Element concentrations in surface soils of the Coconino Plateau, Grand Canyon region, Coconino County, Arizona

Science.gov (United States)

Van Gosen, Bradley S.

2016-09-15

This report provides the geochemical analyses of a large set of background soils collected from the surface of the Coconino Plateau in northern Arizona. More than 700 soil samples were collected at 46 widespread areas, sampled from sites that appear unaffected by mineralization and (or) anthropogenic contamination. The soils were analyzed for 47 elements, thereby providing data on metal concentrations in soils representative of the plateau. These background concentrations can be used, for instance, for comparison to metal concentrations found in soils potentially affected by natural and anthropogenic influences on the Coconino Plateau in the Grand Canyon region of Arizona.The soil sampling survey revealed low concentrations for the metals most commonly of environmental concern, such as arsenic, cobalt, chromium, copper, mercury, manganese, molybdenum, lead, uranium, vanadium, and zinc. For example, the median concentrations of the metals in soils of the Coconino Plateau were found to be comparable to the mean values previously reported for soils of the western United States.

Denan Depression controlled by northeast-directed Olongbulak Thrust Zone in northeastern Qaidam basin: Implications for growth of northern Tibetan Plateau

Science.gov (United States)

Yu, Xiangjiang; Guo, Zhaojie; Zhang, Qiquan; Cheng, Xiang; Du, Wei; Wang, Zhendong; Bian, Qing

2017-10-01

The Denan Depression is a unique depression in the northeastern Qaidam basin, with a maximum Cenozoic sedimentary thickness of 5 km. Detailed field work, interpretation of seismic profiles and analyzation of well data were conducted to define the Cenozoic tectonic evolution of the northeastern Qaidam basin. All geological evidences indicate that the Denan Depression is controlled by the northeast-directed Olongbulak Thrust at its southern boundary. The Denan Depression grew in concert with the development of the northeast-directed Olongbulak Thrust at least since it began to accept the Xiaganchaigou Formation, supporting the early Cenozoic growth of the northern Tibetan Plateau. Surface and subsurface data both point to enhanced tectonic activity since the Quaternary in the northeastern Qaidam basin, leading to a more individual Denan Depression relative to the main Qaidam basin. The northern boundary of the Denan Depression is a passive boundary, and no foreland developed at the northern slope of the Denan Depression.

Peripheral laser iridoplasty opens angle in plateau iris by thinning the cross-sectional tissues

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Liu J

2013-09-01

Full Text Available Ji Liu,1,2 Tania Lamba,1 David A Belyea1 1Department of Ophthalmology, The George Washington University, Washington DC, USA; 2Yale Eye Center, Yale University, New Haven, CT, USA Abstract: Plateau iris syndrome has been described as persistent angle narrowing or occlusion with intraocular pressure elevation after peripheral iridotomy due to the abnormal plateau iris configuration. Argon laser peripheral iridoplasty (ALPI is an effective adjunct procedure to treat plateau iris syndrome. Classic theory suggests that the laser causes the contraction of the far peripheral iris stroma, "pulls" the iris away from the angle, and relieves the iris-angle apposition. We report a case of plateau iris syndrome that was successfully treated with ALPI. Spectral domain optical coherence tomography confirmed the angle was open at areas with laser treatment but remained appositionally closed at untreated areas. Further analysis suggested significant cross-sectional thinning of the iris at laser-treated areas in comparison with untreated areas. The findings indicate that APLI opens the angle, not only by contracting the iris stroma, but also by thinning the iris tissue at the crowded angle. This is consistent with the ALPI technique to aim at the iris as far peripheral as possible. This case also suggests that spectral domain optical coherence tomography is a useful adjunct imaging tool to gonioscopy in assessing the angle condition. Keywords: plateau iris, optic coherence tomography, argon laser peripheral iridoplasty, angle-closure glaucoma

Pseudoarthrosis of medial tibial plateau fracture-role of alignment procedure

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Devgan Ashish

2013-04-01

Full Text Available 【Abstract】 Nonunion in tibial plateau fractures is very rare. Limited literature is available on Pubmed search on intraarticular tibial nonunion. Most of the cases reported have been following failed surgical treatment and none was neglected fractures. Three patients of isolated and neglected medial tibial plateau nonunion with almost similar demo-graphic profile are reported in this paper. All the three pa-tients were managed by minimally invasive compression fixation using lag screws supplemented with limb realign-ment procedure of high tibial osteotomy. We discussed the injury mechanism, management and rehabilitation in such cases and reviewed the available literature regarding such a presentation. Key words: Fracture healing; Tibial fractures; Frac-ture fixation; Osteotomy

[Simulation of Stipa purpurea distribution pattern on Tibetan Plateau based on MaxEnt model and GIS].

Science.gov (United States)

Hu, Zhong-jun; Zhang, Yi-li; Yu, Hai-bin

2015-02-01

The impact of climate change on species distribution is a hot issue in biogeography research. This study utilized the constructive species Stipa purpurea as the research object, which was widely distributed in alpine meadow of the Tibetan Plateau, investigated its distribution in the Tibetan Plateau through the field survey and herbarium search, and used MaxEnt model to simulate its historical, current and future distribution trends to analyze its distribution pattern in each historical period and explore the cause of species distribution changes. Research results showed that diversity of Stipa species in alpine grassland of the Tibetan Plateau was high, its main distribution area was the hinterland of the Tibetan Plateau and areas along the Himalaya, and its distribution was strongly affected by precipitation of warmest quarter, precipitation of wettest quarter and annual precipitation. According to the distribution pattern of S. purpurea in the Last Glacial Maximum, and geographical and geological features of the Tibetan Plateau, this paper proposed that: North Tibet core area of South Qiangtang and Ali region of west Himalaya mountainous area were the core area of the potential distribution for S. purpurea, since these regions could provide more suitable habitats for S. purpurea than other regions and be the refugia where the current S. purpurea was migrated and differentiated from. The presence of refugia may contribute to the understanding of related issues of the alpine plants' origin and differentiation in the Tibetan Plateau.

Glacier mass changes on the Tibetan Plateau 2003–2009 derived from ICESat laser altimetry measurements

International Nuclear Information System (INIS)

Neckel, N; Kropáček, J; Hochschild, V; Bolch, T

2014-01-01

Glacier mass changes are a valuable indicator of climate variability and monsoon oscillation on the underexplored Tibetan Plateau. In this study data from the Ice Cloud and Elevation Satellite (ICESat) is employed to estimate elevation and mass changes of glaciers on the Tibetan Plateau between 2003 and 2009. In order to get a representative sample size of ICESat measurements, glaciers on the Tibetan Plateau were grouped into eight climatically homogeneous sub-regions. Most negative mass budgets of − 0.77 ± 0.35 m w.e. a −1 were found for the Qilian Mountains and eastern Kunlun Mountains while a mass gain of + 0.37 ± 0.25 m w.e. a −1 was found in the westerly-dominated north-central part of the Tibetan Plateau. A total annual mass budget of − 15.6 ± 10.1 Gt a −1 was estimated for the eight sub-regions sufficiently covered by ICESat data which represents ∼80% of the glacier area on the Tibetan Plateau. 13.9 ± 8.9 Gt a −1 (or 0.04 ± 0.02 mm a −1 sea-level equivalent) of the total mass budget contributed ‘directly’ to the global sea-level rise while 1.7 ± 1.9 Gt a −1 drained into endorheic basins on the plateau. (paper)

Distributional patterns of anemophilous tree pollen indicating the pathways of Indian monsoon through Qinghai–Tibetan Plateau

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Zhi-Yong Zhang

2017-10-01

Full Text Available The distribution pattern of vegetation on Qinghai–Tibetan Plateau is fundamentally influenced by the plateau climate, which is mainly controlled by Indian monsoon during summer. The long distance transportation of pollen (mostly anemophilous taxa produced by trees on the plateau has been recorded by modern pollen samples in previous studies, and hypothesized to be a good indicator of monsoon dynamics. Here we use 270 surface pollen samples from Qinghai–Tibetan Plateau to test the distribution patterns of the anemophilous tree pollen. Meanwhile factors related to Indian monsoon affecting pollen transportation are simulated and analyzed. Results show that depositional patterns of anemophilous tree pollen, especially Abies, Pinus, Quercus and Betula are completely controlled by the pathways of Indian monsoon. This is reflected by climatic indicators of the atmospheric pressure pattern over June–July–August, by the precipitation pattern over June–July–August and by the topographic feature of the plateau. The spatial interpolation of thin plate spline results also display two depositional centers (ca. 30°N, 95°E and 30°N, 105°E of the anemophilous tree pollen. In contrast to previous conclusion that pollen distributional pattern is determined by mean annual precipitation, we argue that Indian monsoon is the essential controller because of the synchronization between timing of monsoon wind and timing of plants flowering. Our finding strongly suggests that distributional pattern of anemophilous tree pollen on the plateau is a good proxy of Indian monsoon.

Dose-rate effects in plateau-phase cultures of S3 HeLa and V79 cells

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.; Bailey, S.M.

1979-01-01

Dose-rate effects on cell survival were studied for log-, fed plateau-, and unfed plateau-phase cultures of V79 and S3 HeLa cells. For log-phase cultures, repair, cell-cycle redistribution, and cell division during exposure can contribute to the overall dose-rate effect, but their relative contributions are difficult to determine. With plateau-phase cultures, the cell-cycle times are greatly lengthened, for those cells that are in cycle. Hence, the contribution to the overall dose-rate effect of cell-cycle redistribution and cell division during the exposure could be minimized using plateau-phase cultures. With respect to the acute dose-survival curves, there was a clear loss in effectiveness when the dose rate was lowered to 154 rad/hr for both fed and unfed plateau-phase HeLa and V79 cells. There was no further reduction in effectiveness per unit dose, however, when the dose rate was reduced to 55 rad/hr. Since there was virtually no cell division or cell-cycle redistribution, it may be that a limit to the repair-dependent dose-rate effect at 37 0 C has been reached at a dose rate of 154 rad/hr

Minimal surfaces, stratified multivarifolds, and the plateau problem

CERN Document Server

Thi, Dao Trong; Primrose, E J F; Silver, Ben

1991-01-01

Plateau's problem is a scientific trend in modern mathematics that unites several different problems connected with the study of minimal surfaces. In its simplest version, Plateau's problem is concerned with finding a surface of least area that spans a given fixed one-dimensional contour in three-dimensional space--perhaps the best-known example of such surfaces is provided by soap films. From the mathematical point of view, such films are described as solutions of a second-order partial differential equation, so their behavior is quite complicated and has still not been thoroughly studied. Soap films, or, more generally, interfaces between physical media in equilibrium, arise in many applied problems in chemistry, physics, and also in nature. In applications, one finds not only two-dimensional but also multidimensional minimal surfaces that span fixed closed "contours" in some multidimensional Riemannian space. An exact mathematical statement of the problem of finding a surface of least area or volume requir...

Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Interim Post-Desiccation Monitoring Results

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chronister, Glen B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-09-01

A field test of desiccation is being conducted as an element of the deep vadose zone treatability test program. Desiccation technology relies on removal of water from a portion of the subsurface such that the resultant low moisture conditions inhibit downward movement of water and dissolved contaminants. Previously, a field test report (Truex et al. 2012a) was prepared describing the active desiccation portion of the test and initial post-desiccation monitoring data. Additional monitoring data have been collected at the field test site during the post-desiccation period and is reported herein along with interpretation with respect to desiccation performance. This is an interim report including about 2 years of post-desiccation monitoring data.

Mapping of lithologic and structural units using multispectral imagery. [Afar-Triangle/Ethiopia and adjacent areas (Ethiopian Plateau, Somali Plateau, and parts of Yemen and Saudi Arabia)

Science.gov (United States)

Kronberg, P. (Principal Investigator)

1974-01-01

The author has identified the following significant results. ERTS-1 MSS imagery covering the Afar-Triangle/Ethiopia and adjacent regions (Ethiopian Plateau, Somali Plateau, and parts of Yemen and Saudi Arabi) was applied to the mapping of lithologic and structural units of the test area at a scale 1:1,000,000. Results of the geological evaluation of the ERTS-1 imagery of the Afar have proven the usefullness of this type of satellite data for regional geological mapping. Evaluation of the ERTS images also resulted in new aspects of the structural setting and tectonic development of the Afar-Triangle, where three large rift systems, the oceanic rifts of the Red Sea and Gulf of Aden and the continental East African rift system, seem to meet each other. Surface structures mapped by ERTS do not indicate that the oceanic rift of the Gulf of Aden (Sheba Ridge) continues into the area of continental crust west of the Gulf of Tadjura. ERTS data show that the Wonji fault belt of the African rift system does not enter or cut through the central Afar. The Aysha-Horst is not a Horst but an autochthonous spur of the Somali Plateau.

Long-term, deep-mantle support of the Ethiopia-Yemen Plateau

Science.gov (United States)

Sembroni, Andrea; Faccenna, Claudio; Becker, Thorsten W.; Molin, Paola; Abebe, Bekele

2016-04-01

Ethiopia is a key site to investigate the interactions between mantle dynamics and surface processes because of the presence of the Main Ethiopian Rift (MER), Cenozoic continental flood basalt volcanism, and plateau uplift. The role of mantle plumes in causing Ethiopia's flood basalts and tectonics has been commonly accepted. However, the location and number of plumes and their impact on surface uplift are still uncertain. Here, we present new constraints on the geological and topographic evolution of the Ethiopian Plateau (NW Ethiopia) prior to and after the emplacement of the large flood basalts (40-20 Ma). Using geological information and topographic reconstructions, we show that the large topographic dome that we see today is a long-term feature, already present prior the emplacement of the flood basalts. We also infer that large-scale doming operated even after the emplacement of the flood basalts. Using a comparison with the present-day topographic setting we show that an important component of the topography has been and is presently represented by a residual, non-isostatic, dynamic contribution. We conclude that the growth of the Ethiopian Plateau is a long-term, probably still active, dynamically supported process. Our arguments provide constraints on the processes leading to the formation of one of the largest igneous plateaus on Earth.

Diversity and Ecology of Dendrobiums (Orchidaceae in Chotanagpur Plateau, India

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Pankaj Kumar

2011-03-01

Full Text Available As part of All India Coordinated Research Project on Taxonomy of orchids (AICOPTAX Chotanagpur Plateau was surveyed extensively for documentation of orchid species and distribution during 2002 -2006. Sixty three species were collected from the study area with Dendrobium as one of the largest group of epiphytic orchids comprising of 11 species, namely, Dendrobium aphyllum, D. bicameratum, D. cucullatum, D. crepidatum, D. formosum, D. fimbriatum, D. herbaceum, D. moschatum, D. peguanum, D. regium and D. transparens. Most of the species were found in the Sal (Shorea robusta dominated forests. Stratified Random Sampling was used for ecological studies in the forested regions on the plateau. Results show that D. aphyllum was the most common amongst 11 species and it was distributed through out the altitudinal gradient, whereas, rest of the orchid species were found to be localised at comparatively higher altitudes. D. herbaceum was always found on the upper areas of the plateaus between 900-1000 m asl. D. crepidatum was seen in both epiphytic as well as lithophytic conditions, whereas D. moschatum were found growing as lithophytes along the streams. Rest of the species were epithytic. The paper also deals some microhabitat features governing the distribution of these orchids on the plateau along with their key for identification.

Repair of potentially lethal damage in unfed plateau phase cultures of Ehrlich ascited tumour cells

International Nuclear Information System (INIS)

Illiakis, G.

1980-01-01

Plateau phase EAT-cells have been irradiated at different times in the plateau phase and their ability to repair PLD has been measured. A large capacity to repair PLD has been observed if the cultures were kept in the plateau phase for some hours after irradiation before diluting and plating to measure the survival. In combination with theoretical considerations it is concluded that almost all the PLD produced under these conditions can be repaired. The reaction rate of this repair was independent of the dose and the age of the culture. The results also indicate that PLD repair is independent of the intercellular contact of EAT-cells. (author)

Growing season carries stronger contributions to albedo dynamics on the Tibetan plateau.

Science.gov (United States)

Tian, Li; Chen, Jiquan; Zhang, Yangjian

2017-01-01

The Tibetan Plateau has experienced higher-than-global-average climate warming in recent decades, resulting in many significant changes in ecosystem structure and function. Among them is albedo, which bridges the causes and consequences of land surface processes and climate. The plateau is covered by snow/ice and vegetation in the non-growing season (nGS) and growing season (GS), respectively. Based on the MODIS products, we investigated snow/ice cover and vegetation greenness in relation to the spatiotemporal changes of albedo on the Tibetan Plateau from 2000 through 2013. A synchronous relationship was found between the change in GSNDVI and GSalbedo over time and across the Tibetan landscapes. We found that the annual average albedo had a decreasing trend, but that the albedo had slightly increased during the nGS and decreased during the GS. Across the landscapes, the nGSalbedo fluctuated in a synchronous pattern with snow/ice cover. Temporally, monthly snow/ice coverage also had a high correspondence with albedo, except in April and October. We detected clear dependencies of albedo on elevation. With the rise in altitude, the nGSalbedo decreased below 4000 m, but increased for elevations of 4500-5500 m. Above 5500 m, the nGSalbedo decreased, which was in accordance with the decreased amount of snow/ice coverage and the increased soil moisture on the plateau. More importantly, the decreasing albedo in the most recent decade appeared to be caused primarily by lowered growing season albedo.

Growing season carries stronger contributions to albedo dynamics on the Tibetan plateau.

Directory of Open Access Journals (Sweden)

Li Tian

Full Text Available The Tibetan Plateau has experienced higher-than-global-average climate warming in recent decades, resulting in many significant changes in ecosystem structure and function. Among them is albedo, which bridges the causes and consequences of land surface processes and climate. The plateau is covered by snow/ice and vegetation in the non-growing season (nGS and growing season (GS, respectively. Based on the MODIS products, we investigated snow/ice cover and vegetation greenness in relation to the spatiotemporal changes of albedo on the Tibetan Plateau from 2000 through 2013. A synchronous relationship was found between the change in GSNDVI and GSalbedo over time and across the Tibetan landscapes. We found that the annual average albedo had a decreasing trend, but that the albedo had slightly increased during the nGS and decreased during the GS. Across the landscapes, the nGSalbedo fluctuated in a synchronous pattern with snow/ice cover. Temporally, monthly snow/ice coverage also had a high correspondence with albedo, except in April and October. We detected clear dependencies of albedo on elevation. With the rise in altitude, the nGSalbedo decreased below 4000 m, but increased for elevations of 4500-5500 m. Above 5500 m, the nGSalbedo decreased, which was in accordance with the decreased amount of snow/ice coverage and the increased soil moisture on the plateau. More importantly, the decreasing albedo in the most recent decade appeared to be caused primarily by lowered growing season albedo.

Erosion patterns produced by the paleo Haizishan ice cap, SE Tibetan Plateau

Science.gov (United States)

Fu, P.; Stroeven, A. P.; Harbor, J.; Hättestrand, C.; Heyman, J.; Caffee, M. W.

2017-12-01

Erosion is a primary driver of landscape evolution, topographic relief production, geochemical cycles, and climate change. Combining in situ 10Be and 26Al exposure age dating, geomorphological mapping, and field investigations, we examine glacial erosion patterns of the almost 4,000 km2 paleo Haizishan ice cap on the southeastern Tibetan Plateau. Our results show that ice caps on the low relief Haizishan Plateau produced a zonal pattern of landscape modification. In locations where apparent exposure ages on bedrock are consistent with the last deglaciation, complete resetting of the cosmogenic exposure age clock indicates glacial erosion of at least a few meters. However, older apparent exposure ages on bedrock in areas known to have been covered by the paleo ice cap during the Last Glacial Maximum indicate inheritance and thus limited glacial erosion. Inferred surface exposure ages from cosmogenic depth profiles through two saprolites vary from resetting and thus saprolite profile truncation to nuclide inheritance indicating limited erosion. Finally, significant nuclide inheritance in river sand samples from basins on the scoured plateau surface also indicate limited glacial erosion during the last glaciation. Hence, for the first time, our study shows clear evidence of preservation under non-erosive ice on the Tibetan Plateau. As patterns of glacial erosion intensity are largely driven by the basal thermal regime, our results confirm earlier inferences from geomorphology for a concentric basal thermal pattern for the paleo Haizishan ice cap during the LGM.

A study of cloud microphysics and precipitation over the Tibetan Plateau by radar observations and cloud-resolving model simulations: Cloud Microphysics over Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

Gao, Wenhua [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China; Pacific Northwest National Laboratory, Richland Washington USA; Sui, Chung-Hsiung [Department of Atmospheric Sciences, National Taiwan University, Taipei Taiwan; Fan, Jiwen [Pacific Northwest National Laboratory, Richland Washington USA; Hu, Zhiqun [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China; Zhong, Lingzhi [State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing China

2016-11-27

Cloud microphysical properties and precipitation over the Tibetan Plateau (TP) are unique because of the high terrains, clean atmosphere, and sufficient water vapor. With dual-polarization precipitation radar and cloud radar measurements during the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-III), the simulated microphysics and precipitation by the Weather Research and Forecasting model (WRF) with the Chinese Academy of Meteorological Sciences (CAMS) microphysics and other microphysical schemes are investigated through a typical plateau rainfall event on 22 July 2014. Results show that the WRF-CAMS simulation reasonably reproduces the spatial distribution of 24-h accumulated precipitation, but has limitations in simulating time evolution of precipitation rates. The model-calculated polarimetric radar variables have biases as well, suggesting bias in modeled hydrometeor types. The raindrop sizes in convective region are larger than those in stratiform region indicated by the small intercept of raindrop size distribution in the former. The sensitivity experiments show that precipitation processes are sensitive to the changes of warm rain processes in condensation and nucleated droplet size (but less sensitive to evaporation process). Increasing droplet condensation produces the best area-averaged rain rate during weak convection period compared with the observation, suggesting a considerable bias in thermodynamics in the baseline simulation. Increasing the initial cloud droplet size causes the rain rate reduced by half, an opposite effect to that of increasing droplet condensation.

Lithosphere density structure beneath the eastern margin of the Tibetan Plateau and its surrounding areas derived from GOCE gradients data

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Honglei Li

2017-05-01

Full Text Available A three-dimensional density model of the crust and uppermost mantle is determined by the inversion of a set of GOCE gravity and gradients residual anomalies beneath the eastern margin of the Tibetan Plateau and its surrounding areas. In our work, we choose five independent gravity gradients (Txx, Tzz, Txy, Txz, Tyz to perform density inversion. Objective function is given based on Tikhonov regularization theory. Seismic S-wave velocities play the role of initial constraint for the inversion based on a relationship between density and S-wave velocity. Damped Least Square method is used during the inversion. The final density results offer some insights into understanding the underlying geodynamic processes: (1 Low densities in the margin of the Tibet, along with low wave velocity and resistivity results, yield conversions from soft and weak Tibet to the hard and rigid cratons. (2The lowest densities are found in the boundary of the plateau, instead of the whole Tibet indicates that the effects of extrusion stress environment in the margin affect the changes of the substance there. The substances and environments conditioning for the earthquake preparations and strong deformation in this transitional zone. (3 Evident low-D anomaly in the upper and middle crust in the Lasha terrane and Songpan-Ganzi terrane illustrated the eastward sub-ducted of southeastern Tibet, which could be accounts for the frequent volcano and earthquakes there.

Numberical Calculations of Atmospheric Conditions over Tibetan Plateau by Using WRF Model

International Nuclear Information System (INIS)

Qian, Xuan; Yao, Yongqiang; Wang, Hongshuai; Liu, Liyong; Li, Junrong; Yin, Jia

2015-01-01

The wind field, precipitable water vapor are analyzed by using the mesoscale numerical model WRF over Tibetan Plateau, and the aerosol is analyzed by using WRF- CHEM model. The spatial and vertical distributions of the relevant atmospheric factors are summarized, providing truth evidence for selecting and further evaluating an astronomical site. It has been showed that this method could provide good evaluation of atmospheric conditions. This study serves as a further demonstration towards astro-climate regionalization, and provides with essential database for astronomical site survey over Tibetan Plateau. (paper)

Diurnal variations of summertime precipitation over the Tibetan Plateau in relation to orographically-induced regional circulations

International Nuclear Information System (INIS)

Liu Xiaodong; Bai Aijuan; Liu Changhai

2009-01-01

The diurnal patterns of variation of summertime precipitation over the Tibetan Plateau were first investigated using the TRMM multi-satellite precipitation analysis product for five summer seasons (i.e. June to August for 2002-2006). Both hourly precipitation amount and precipitation frequency exhibit pronounced daily variability with an overall late-afternoon-evening maximum and a dominant morning minimum. A notable exception is the prevalent nocturnal maximum around the periphery of the Plateau. In terms of the normalized harmonic amplitude, the diurnal signal shows significant regional contrast with the strongest manifestation over the central Plateau and the weakest near the periphery. This remarkable spatial dependence in daily rainfall cycles is clear evidence of orographic and heterogeneous land-surface impacts on convective development. Using six-hourly NCEP FNL data, we then examined the diurnal variability in the atmospheric circulation and thermodynamics in this region. The results show that the Plateau heats (cools) the overlying atmosphere during the day (night) more than the surrounding areas, and as a consequence a relatively stronger confluent circulation in this region occurs during the day than during the night, consistent with the diurnal rainfall cycles. Moreover, the regions with large low-level convergence and upper-level divergence correspond to the strong diurnal rainfall variations. The reversed daily alterations of convergence-divergence patterns in the vicinity of the Plateau edges are in agreement with the observed nighttime rainfall peak therein. This study further demonstrates the importance of the Tibetan Plateau in regulating regional circulation and precipitation.

Impact of Cryosphere Hydrological Changes on the River Runoff in the Tibetan Plateau

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Wang, Y.; Yang, D.

2015-12-01

The Tibetan Plateau is the headwaters of many major rivers in Asia, the change in streamflow is significant for social and economic development and natural ecology in the middle and lower reaches. Located in the alpine region, streamflow in the plateau is mainly affected by the cryosphere hydrological processes. Due to global warming in recent decades, the Tibetan Plateau is experiencing glaciers shrinking and permafrost degradation. Accelerated glacier melt led to the increasing meltwater, thus affecting the streamflow. Permafrost is an important factor in stabilizing the water cycle and streamflow, the ecological degradation and the significant changes of rivers, lakes, swamps, wetlands and other hydrological environment in recent decades in the Tibetan plateau is closely related to permafrost degradation. Therefore, it is important to explore the impact of cryosphere hydrological changes on the streamflow for the future water management. This study uses a method of base flow separation and a stepwise multiple regression model to investigate the reasons for the runoff changes in different regions of the Tibetan Plateau during 1960-2000. The contribution of glacier melt to annual runoff is particularly estimated to explore the possible influences of soil freezing and thawing on annual runoff changes. The results show an increasing trend of the annual runoff in the upstream of Nujiang River, Lancang River and Qilian Mountains, dominated by the increasing of base flow; and a decreasing trend of the runoff in the upper reach of the Yarlung Zangbo River, Yellow River and Yangtze River, dominated by the reduction of quick flow. Change in the amount of runoff was mainly due to change in precipitation. Rising temperature accelerates the melting of glaciers and increases the summer quick flow. In addition, rising temperature may reduce the quick flow and increase the base flow due to change of the active permafrost layers, which leads to the increase of soil water storage

Neglected, semimembranosus osteochondral avulsion fracture of the posteromedial tibial plateau

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Rakesh John

2018-06-01

Full Text Available Semimembranosus avulsion fracture is infrequently reported and is easy to miss on plain radiographs; the mechanism of injury is highly controversial. Initial reports linked it to anterior cruciate ligament and medial meniscal tears. We report an osteochondral semimembranosus avulsion fracture of the posteromedial tibial plateau with associated posterior cruciate ligament rupture. Also described is a novel surgical fixation technique for such osteochondral fractures where the surgical exposure is limited due to the obliquity of the fracture line resulting in a greater involvement of the articular cartilage than the small bony component. The fixation technique described may be used for osteochondral fractures where the application of a conventional compression screw may not be feasible. Keywords: Osteochondral fracture, Semimembranosus avulsion fracture, Posteromedial tibial plateau, Neglected, Nonunion

Three-dimensional Upper Crustal Velocity and Attenuation Structures of the Central Tibetan Plateau from Local Earthquake Tomography

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Zhou, B.; Liang, X.; Lin, G.; Tian, X.; Zhu, G.; Mechie, J.; Teng, J.

2017-12-01

A series of V-shaped conjugate strike-slip faults are the most spectacular geologic features in the central Tibetan plateau. A previous study suggested that this conjugate strike-slip fault system accommodates the east-west extension and coeval north-south contraction. Another previous study suggested that the continuous convergence between the Indian and Eurasian continents and the eastward asthenospheric flow generated lithospheric paired general-shear (PGS) deformation, which then caused the development of conjugate strike-slip faults in central Tibet. Local seismic tomography can image three dimensional upper-crustal velocity and attenuation structures in central Tibet, which will provide us with more information about the spatial distribution of physical properties and compositional variations around the conjugate strike-slip fault zone. Ultimately, this information could improve our understanding of the development mechanism of the conjugate strike-slip fault system. In this study, we collected 6,809 Pg and 2,929 Sg arrival times from 414 earthquakes recorded by the temporary SANDWICH and permanent CNSN networks from November 2013 to November 2015. We also included 300 P and 17 S arrival times from 12 shots recorded by the INDEPTH III project during the summer of 1998 in the velocity tomography. We inverted for preliminary Vp and Vp/Vs models using the SIMUL2000 tomography algorithm, and then relocated the earthquakes with these preliminary velocity models. After that, we inverted for the final velocity models with these improved source locations and origin times. After the velocity inversion, we performed local attenuation tomography using t* measurements from the same dataset with an already existing approach. There are correlated features in the velocity and attenuation structures. From the surface to 10 km depth, the study area is dominated by high Vp and Qp anomalies. However, from 10 km to 20 km depth, there is a low Vp and Qp zone distributed along the

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures.

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Castiglia, Marcello Teixeira; Nogueira-Barbosa, Marcello Henrique; Messias, Andre Marcio Vieira; Salim, Rodrigo; Fogagnolo, Fabricio; Schatzker, Joseph; Kfuri, Mauricio

2018-02-14

Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane-oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two-dimensional videos of computed tomography, and three-dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter- and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi-square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker ( p  < 0.01). The addition of

Les jeux de plateau: une géographie ludique

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Frédéric BIZET

1997-12-01

Full Text Available Les jeux de plateau utilisent le plus souvent une carte «papier» comme support. Au-delà de l'aspect cartographique, ces jeux intègrent également des notions de territorialité et d'analyse spatiale.

Human-computer interfaces applied to numerical solution of the Plateau problem

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Elias Fabris, Antonio; Soares Bandeira, Ivana; Ramos Batista, Valério

2015-09-01

In this work we present a code in Matlab to solve the Problem of Plateau numerically, and the code will include human-computer interface. The Problem of Plateau has applications in areas of knowledge like, for instance, Computer Graphics. The solution method will be the same one of the Surface Evolver, but the difference will be a complete graphical interface with the user. This will enable us to implement other kinds of interface like ocular mouse, voice, touch, etc. To date, Evolver does not include any graphical interface, which restricts its use by the scientific community. Specially, its use is practically impossible for most of the Physically Challenged People.

Satellite precipitation estimation over the Tibetan Plateau

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Porcu, F.; Gjoka, U.

2012-04-01

Precipitation characteristics over the Tibetan Plateau are very little known, given the scarcity of reliable and widely distributed ground observation, thus the satellite approach is a valuable choice for large scale precipitation analysis and hydrological cycle studies. However,the satellite perspective undergoes various shortcomings at the different wavelengths used in atmospheric remote sensing. In the microwave spectrum often the high soil emissivity masks or hides the atmospheric signal upwelling from light-moderate precipitation layers, while low and relatively thin precipitating clouds are not well detected in the visible-infrared, because of their low contrast with cold and bright (if snow covered) background. In this work an IR-based, statistical rainfall estimation technique is trained and applied over the Tibetan Plateau hydrological basin to retrive precipitation intensity at different spatial and temporal scales. The technique is based on a simple artificial neural network scheme trained with two supervised training sets assembled for monsoon season and for the rest of the year. For the monsoon season (estimated from June to September), the ground radar precipitation data for few case studies are used to build the training set: four days in summer 2009 are considered. For the rest of the year, CloudSat-CPR derived snowfall rate has been used as reference precipitation data, following the Kulie and Bennartz (2009) algorithm. METEOSAT-7 infrared channels radiance (at 6.7 and 11 micometers) and derived local variability features (such as local standard deviation and local average) are used as input and the actual rainrate is obtained as output for each satellite slot, every 30 minutes on the satellite grid. The satellite rainrate maps for three years (2008-2010) are computed and compared with available global precipitation products (such as C-MORPH and TMPA products) and with other techniques applied to the Plateau area: similarities and differences are

A Mechanism of Land Degradation in Turf-Mantled Slopes of the Tibetan Plateau

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Okin, Gregory S.; D'Odorico, Paolo; Liu, Jianquan

2018-05-01

Kobresia pygmaea meadows are typical of Tibetan Plateau landscapes in the 3,000 to 5,500 m elevation range and constitute the most extensive alpine ecosystem in the world. Kobresia pygmaea forms turf mats that stabilize the surface and shelter the underlying soils from water erosion. Large tracts of the Plateau, however, exhibit signs of ongoing degradation of the turf and erosion of the underlying soil. Despite the crucial role played by K. pygmaea turf mats in the stabilization of the headwaters of major Asian rivers, the mechanisms responsible for their degradation remain poorly investigated. Here we develop a process-based model of land degradation of Tibetan Plateau slopes, which accounts for (i) turf cracking, (ii) water flow concentration in the cracks, (iii) crack widening by scouring, and (iv) sheet-flow erosion. As expected, soil erosion increases with the slope and drainage area (hence the observation of stronger erosion in relatively steep downhill sites). Model simulations indicate that with a sensible set of parameters representative of soil and hydrologic conditions in the region, Tibetan Plateau landscapes are vulnerable to turf mat degradation and soil erosion. As soon as polygonal cracks develop, water flow widens them until the landscape is completely barren. At this point sheet flow eventually erodes the mineral soil leaving behind a highly degraded landscape.

Effectiveness of 10 polymorphic microsatellite markers for parentage and pedigree analysis in plateau pika (Ochotona curzoniae

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Zhang Yanming

2010-11-01

Full Text Available Abstract Background The plateau pika (Ochotona curzoniae is an underground-dwelling mammal, native to the Tibetan plateau of China. A set of 10 polymorphic microsatellite loci has been developed earlier. Its reliability for parentage assignment has been tested in a plateau pika population. Two family groups with a known pedigree were used to validate the power of this set of markers. Results The error in parentage assignment using a combination of these 10 loci was very low as indicated by their power of discrimination (0.803 - 0.932, power of exclusion (0.351 - 0.887, and an effectiveness of the combined probability of exclusion in parentage assignment of 99.999%. Conclusion All the offspring of a family could be assigned to their biological mother; and their father or relatives could also be identified. This set of markers therefore provides a powerful and efficient tool for parentage assignment and other population analyses in the plateau pika.

The Colorado Plateau V: research, environmental planning, and management for collaborative conservation

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Villarreal, Miguel L.; van Riper, Carena J.; Johnson, Matthew J.; van Riper, Charles

2012-01-01

Roughly centered on the Four Corners region of the southwestern United States, the Colorado Plateau covers some 130,000 square miles of sparsely vegetated plateaus, mesas, canyons, arches, and cliffs in Arizona, Utah, Colorado, and New Mexico. With elevations ranging from 3,000 to 14,000 feet, the natural systems found within the plateau are dramatically varied, from desert to alpine conditions. This volume, the fifth from the University of Arizona Press and the tenth overall, focuses on adaptation of resource management and conservation to climate change and water scarcity, protecting biodiversity through restructured energy policies, ensuring wildlife habitat connectivity across barriers, building effective conservation networks, and exploring new opportunities for education and leadership in conservation science. An informative read for people interested in the conservation and natural history of the region, the book will also serve as a valuable reference for those people engaged in the management of cultural and biological resources of the Colorado Plateau, as well as scientists interested in methods and tools for land and resource management throughout the West.

Stable isotope variations (δ18O and δD) in modern waters across the Andean Plateau

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Bershaw, John; Saylor, Joel E.; Garzione, Carmala N.; Leier, Andrew; Sundell, Kurt E.

2016-12-01

Environmental parameters that influence the isotopic composition of meteoric water (δ18O and δD) are well characterized up the windward side of mountains, where orographic precipitation results in a predictable relationship between the isotopic composition of precipitation and elevation. The topographic and climatic evolution of the Andean Plateau and surrounding regions has been studied extensively by exploiting this relationship through the use of paleowater proxies. However, interpretation on the plateau itself is challenged by a poor understanding of processes that fractionate isotopes during vapor transport and rainout, and by the relative contribution of unique moisture sources. Here, we present an extensive dataset of modern surface water samples for the northern Andean Plateau and surrounding regions to elucidate patterns and causes of isotope fractionation in this continental environment. These data show a progressive increase in δ18O of stream water west of the Eastern Cordillera (∼1‰/70 km), almost identical to the rate observed across the Tibetan Plateau, attributed to a larger fraction of recycled water in precipitation and/or increased evaporative enrichment downwind. This may lead to underestimates of paleoelevation, particularly for sites deep into the rainshadow of the Eastern Cordilleran crest. That said, elevation is a primary control on the isotopic composition of surface waters across the entire Andean Plateau and its flanks when considering the most negative δ18O values, highlighting the need for sufficiently large datasets to distinguish minimally evaporated samples. There is a general increase in δ18O on the plateau from north to south, concomitant with an increase in aridity and decrease in convective moistening (amount effect). Lastly, stable isotope and seasonal precipitation patterns suggest easterlies provide the vast majority of moisture that falls as precipitation across the Andean Plateau and Western Cordillera, from Peru to

Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

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X. Yin

2017-09-01

Full Text Available Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of  ∼ 5 years (January 2011 to October 2015, which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau

Surface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

Science.gov (United States)

Yin, Xiufeng; Kang, Shichang; de Foy, Benjamin; Cong, Zhiyuan; Luo, Jiali; Zhang, Lang; Ma, Yaoming; Zhang, Guoshuai; Rupakheti, Dipesh; Zhang, Qianggong

2017-09-01

Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present continuous measurements of surface ozone mixing ratios at Nam Co Station over a period of ˜ 5 years (January 2011 to October 2015), which is a background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb (mean ± standard deviation) was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions inputs, and the anthropogenic contribution from South Asia in spring and China in summer may affect Nam Co Station occasionally. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions, vertical mixing and downward transport of stratospheric air mass. Model results indicate that the study site is affected differently by the surrounding areas in different seasons: air masses from the southern Tibetan Plateau contribute to the high ozone levels in the spring, and enhanced ozone levels in the summer are associated with air masses from the northern Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites on the Tibetan Plateau, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a

Current deformation in the Tibetan Plateau: a stress gauge in the large-scale India-Asia collision tectonics

Science.gov (United States)

Capitanio, F. A.

2017-12-01

The quantification of the exact tectonic forces budget on Earth has remained thus far elusive. Geodetic velocities provide relevant constraints on the current dynamics of the coupling between collision and continental tectonics, however in the Tibetan plateau these support contrasting, non-unique models. Here, we compare numerical models of coupled India-Asia plate convergence, collision and continent interiors tectonics to the geodetically-constrained motions in the Tibetan Plateau to provide a quantitative assessment of the driving forces of plate tectonics in the area. The models develop a range of long-term evolutions remarkably similar to the Asian tectonics in the Cenozoic, reproducing the current large-scale motions pattern under a range of conditions. Balancing the convergent margin forces, following subduction, and the far-field forcing along the trail of the subducting continent, the geodetic rates in the Tibetan Plateau can be matched. The comparisons support the discussion on the likely processes at work, allowing inferences on the drivers of plateau formation and its role on the plate margin-interiors tectonics. More in general, the outcomes highlight the unique role of the Tibetan Plateau as a pressure gauge for the tectonic forces on Earth.

Long-term complications following tibial plateau levelling osteotomy in small dogs with tibial plateau angles > 30°.

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Knight, Rebekah; Danielski, Alan

2018-04-21

Tibial plateau levelling osteotomy (TPLO) is commonly performed for surgical management of cranial cruciate ligament (CCL) disease. It has been suggested that small dogs may have steeper tibial plateau angles (TPAs) than large dogs, which has been associated with increased complication rates after TPLO. A retrospective study was performed to assess the rate and nature of long-term complications following TPLO in small dogs with TPAs>30°. Medical records were reviewed for dogs with TPAs>30° treated for CCL rupture by TPLO with a 2.0 mm plate over a five-year period. Radiographs were assessed to determine TPA, postoperative tibial tuberosity width and to identify any complication. Up-to-date medical records were obtained from the referring veterinary surgeon and any complications in the year after surgery were recorded. The effects of different variables on complication rate were assessed using logistic regression analysis. Minor complications were reported in 22.7 per cent of cases. This is similar to or lower than previously reported complication rates for osteotomy techniques in small dogs and dogs with steep TPAs. A smaller postoperative TPA was the only variable significantly associated with an increased complication rate. No major complications were identified. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Uplift history of a transform continental margin revealed by the stratigraphic record: The case of the Agulhas transform margin along the Southern African Plateau

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Baby, Guillaume; Guillocheau, François; Boulogne, Carl; Robin, Cécile; Dall'Asta, Massimo

2018-04-01

The south and southeast coast of southern Africa (from 28°S to 33°S) forms a high-elevated transform passive margin bounded to the east by the Agulhas-Falkland Fracture Zone (AFFZ). We analysed the stratigraphic record of the Outeniqua and Durban (Thekwini) Basins, located on the African side of the AFFZ, to determine the evolution of these margins from the rifting stage to present-day. The goal was to reconstruct the strike-slip evolution of the Agulhas Margin and the uplift of the inland high-elevation South African Plateau. The Agulhas transform passive margin results from four successive stages: Rifting stage, from Late Triassic to Early Cretaceous ( 200?-134 Ma), punctuated by three successive rifting episodes related to the Gondwana breakup; Wrench stage (134-131 Ma), evidenced by strike- and dip-slip deformations increasing toward the AFFZ; Active transform margin stage (131-92 Ma), during which the Falkland/Malvinas Plateau drifts away along the AFFZ, with an uplift of the northeastern part of the Outeniqua Basin progressively migrating toward the west; Thermal subsidence stage (92-0 Ma), marked by a major change in the configuration of the margin (onset of the shelf-break passive margin morphology). Two main periods of uplift were documented during the thermal subsidence stage of the Agulhas Margin: (1) a 92 Ma short-lived margin-scale uplift, followed by a second one at 76 Ma located along the Outeniqua Basin and; (2) a long-lasting uplift from 40 to 15 Ma limited to the Durban (Thekwini) Basin. This suggests that the South African Plateau is an old Upper Cretaceous relief (90-70 Ma) reactivated during Late Eocene to Early Miocene times (40-15 Ma).

The Seasonal and Intraseasonal Variability of Diurnal Cloud Activity over the Tibetan Plateau

OpenAIRE

Hatsuki, Fujinami; Tetsuzo, Yasunari; Institute of Geoscience, University of Tsukuba; Institute of Geoscience, University of Tsukuba

2001-01-01

Seasonal variation of diurnal cloud activity(abbreviated DCA)over the Tibetan Plateau throughout the year is examined using 3-hourly geostationary meteorological satellite(GMS)data for 6-years(1989-1994). The DCA shows two distinct variance maxima in the seasonal cycle. One is in spring(pre-monsoon season), and the other is in the summer monsoon season. The DCA begins in late January, and reaches its maximum from March through April. The active DCA extends over almost the whole of the plateau...

Malaria prevalence, anemia and baseline intervention coverage prior to mass net distributions in Abia and Plateau States, Nigeria.

Science.gov (United States)

Noland, Gregory S; Graves, Patricia M; Sallau, Adamu; Eigege, Abel; Emukah, Emmanuel; Patterson, Amy E; Ajiji, Joseph; Okorofor, Iheanyichi; Oji, Oji Uka; Umar, Mary; Alphonsus, Kal; Damen, James; Ngondi, Jeremiah; Ozaki, Masayo; Cromwell, Elizabeth; Obiezu, Josephine; Eneiramo, Solomon; Okoro, Chinyere; McClintic-Doyle, Renn; Oresanya, Olusola; Miri, Emmanuel; Emerson, Paul M; Richards, Frank O

2014-03-26

Nigeria suffers the world's largest malaria burden, with approximately 51 million cases and 207,000 deaths annually. As part of the country's aim to reduce by 50% malaria-related morbidity and mortality by 2013, it embarked on mass distribution of free long-lasting insecticidal nets (LLINs). Prior to net distribution campaigns in Abia and Plateau States, Nigeria, a modified malaria indicator survey was conducted in September 2010 to determine baseline state-level estimates of Plasmodium prevalence, childhood anemia, indoor residual spraying (IRS) coverage and bednet ownership and utilization. Overall age-adjusted prevalence of Plasmodium infection by microscopy was similar between Abia (36.1%, 95% CI: 32.3%-40.1%; n = 2,936) and Plateau (36.6%, 95% CI: 31.3%-42.3%; n = 4,209), with prevalence highest among children 5-9 years. P. malariae accounted for 32.0% of infections in Abia, but only 1.4% of infections in Plateau. More than half of children ≤10 years were anemic, with anemia significantly higher in Abia (76.9%, 95% CI: 72.1%-81.0%) versus Plateau (57.1%, 95% CI: 50.6%-63.4%). Less than 1% of households in Abia (n = 1,305) or Plateau (n = 1,335) received IRS in the 12 months prior to survey. Household ownership of at least one bednet of any type was 10.1% (95% CI: 7.5%-13.4%) in Abia and 35.1% (95% CI: 29.2%-41.5%) in Plateau. Ownership of two or more bednets was 2.1% (95% CI: 1.2%-3.7%) in Abia and 14.5% (95% CI: 10.2%-20.3%) in Plateau. Overall reported net use the night before the survey among all individuals, children Abia and 14.7%, 19.1% and 21.0%, respectively in Plateau. Among households owning nets, 34.4% of children Abia used a net, compared to 52.6% of children and 62.7% of pregnant women in Plateau. These results reveal high Plasmodium prevalence and childhood anemia in both states, low baseline coverage of IRS and LLINs, and sub-optimal net use-especially among age groups with highest observed malaria burden.

Spatial distribution and controlling factors of stable isotopes in meteoric waters on the Tibetan Plateau: Implications for paleoelevation reconstruction

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Li, Lin; Garzione, Carmala N.

2017-02-01

Debates persist about the interpretations of stable isotope based proxies for the surface uplift of the central-northern Tibetan Plateau. These disputes arise from the uncertain relationship between elevation and the δ18 O values of meteoric waters, based on modern patterns of isotopes in precipitation and surface waters. We present a large river water data set (1,340 samples) covering most parts of the Tibetan Plateau to characterize the spatial variability and controlling factors of their isotopic compositions. Compared with the amount-weighted mean annual oxygen isotopic values of precipitation, we conclude that river water is a good substitute for isotopic studies of precipitation in the high flat (e.g., elevation >3,300 m) interior of the Tibetan Plateau in the mean annual timescale. We construct, for the first time based on field data, contour maps of isotopic variations of meteoric waters (δ18 O, δD and d-excess) on the Tibetan Plateau. In the marginal mountainous regions of the Plateau, especially the southern through eastern margins, the δ18 O and δD values of river waters decrease with increasing mean catchment elevation, which can be modeled as a Rayleigh distillation process. However, in the interior of the Plateau, northward increasing trends in δ18 O and δD values are pronounced and present robust linear relations; d-excess values are lower than the marginal regions and exhibit distinct contrasts between the eastern (8 ‰- 12 ‰) and western (Asian monsoon and Westerly winds; 2) contribution of moisture from recycled surface water; and 3) sub-cloud evaporation. We further provide a sub-cloud evaporation modified Rayleigh distillation and mixing model to simulate the isotopic variations in the western Plateau. Results of this work suggest that stable isotope-based paleoaltimetry studies are reliable in the southern through eastern Plateau margins; towards the central-northern Plateau, this method cannot be applied without additional

Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

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Bo He

Full Text Available Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

Science.gov (United States)

He, Bo; Wu, Jian Ping; Xu, Jiake; Day, Robert E; Kirk, Thomas Brett

2013-01-01

Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

Late Quaternary paleoseismology of the Milin fault: Implications for active tectonics along the Yarlung Zangbo Suture, Southeastern Tibet Plateau

Science.gov (United States)

Li, Kang; Xu, Xiwei; Kirby, Eric; Tang, Fangtou; Kang, Wenjun

2018-04-01

How the eastward motion of crust in the central Tibetan Plateau is accommodated in the remote regions of the eastern Himalayan syntaxis remains uncertain. Although the Yarlung Zangbo suture (YZS) forms a striking lineament in the topography of the region, evidence for recent faulting along this zone has been equivocal. To understand whether faults along the YZS are active, we performed a geological investigation along the eastern segments of the YZS. Geomorphic observations suggest the presence of active faulting along several segments of the YZS, which we collectively refer to as the "Milin fault". Paleoseismologic data from trenches reveal evidence for one faulting event, which is constrained to occur between 5620 and 1945 a BP. The latest faulting event displaced alluvial surface T2 by 7 m. The offset on this earthquake place the minimum value on the vertical slip rate of 0.3 mm/yr. Empirical relationships between surface rupture length, displacement and magnitude, suggest that magnitude of the latest event could have been Mw 7.3-7.7. On the basis of this slip rate and the elapsed time since the last event, it is estimated that a seismic moment equivalent to Mw 7.0 has been accumulated on the Milin fault. It is pose a threat to the surrounding region. Our results suggest that shortening occurs in the vicinity of the eastern Himalayan syntaxis, and part of eastward motion of crust from the central Tibetan Plateau is absorbed by uplift of the eastern Himalayan syntaxis.

The anterolateral supra-fibular-head approach for plating posterolateral tibial plateau fractures: A novel surgical technique.

Science.gov (United States)

Hu, Sun-Jun; Chang, Shi-Min; Zhang, Ying-Qi; Ma, Zhuo; Du, Shou-Chao; Zhang, Kai

2016-02-01

The posterolateral (PL) tibial plateau quadrant is laterally covered by the fibular head and posteriorly covered by a mass of muscle ligament and important neurovascular structures. There are several limitations in exposing and fixing the PL tibial plateau fractures using a posterior approach. The aim of this study is to present a novel anterolateral supra-fibular-head approach for plating PL tibial plateau fractures. Five fresh and ten preserved knee specimens were dissected to measure the following parameters:1) the vertical distance from the apex of the fibular head to the lateral plateau surface, 2) the transverse distance between the PL platform and fibula collateral ligament (FCL), and 3) the tension of the FCL in different knee flexion positions. Clinically, isolated PL quadrant tibial plateau fractures were treated via an anterolateral supra-fibular-head approach and lateral rafting plate fixation. The outcome of the patients was assessed after a short to medium follow-up period. The distance from the apex of the fibular head to the lateral condylar surface was 12.2 ± 1.6 mm on average. With the knee extended and the FCL tensioned, the transverse distance between the PL platform and the FCL was 6.7 ± 1.1 mm. With the knee flexed to 60° and the FCL was in the most relaxed position, the distance increased to 21.1 ± 3.0 mm. Clinically, a series of 7 cases of PL tibial plateau fractures were treated via this anterolateral supra-fibular-head approach. The patient was placed in a lateral decubitus position with the knee flexed to approximately 60 degrees. After the posterior retraction of the FCL, the plate was placed more posteriorly to provide a raft or horizontal belt fixation of the PL tibial plateau fragment. After an average of 14.3 months of follow up, the knee range of motion(ROM) was 121.4° ± 8.8° (range: 105°-135°), the HSS score was 96.7 ± 2.6 (range: 90-100), and the SMFA dysfunction score was 22.4 ± 3.8 (range: 16-28) points. The

Interannual variability of the normalized difference vegetation index on the Tibetan Plateau and its relationship with climate change

Science.gov (United States)

Zhou, Dingwen; Fan, Guangzhou; Huang, Ronghui; Fang, Zhifang; Liu, Yaqin; Li, Hongquan

2007-05-01

The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes. In this paper, the interannual variations of the plateau vegetation are investigated using a 21-year normalized difference vegetation index (NDVI) dataset to quantify the consequences of climate warming for the regional ecosystem and its interactions. The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north. On the whole, vegetation activity demonstrates a gradual enhancement in an oscillatory manner during 1982 2002. The temporal variation also exhibits striking regional differences: an increasing trend is most apparent in the west, south, north and southeast, whereas a decreasing trend is present along the southern plateau boundary and in the central-east region. Covariance analysis between the NDVI and surface temperature/precipitation suggests that vegetation change is closely related to climate change. However, the controlling physical processes vary geographically. In the west and east, vegetation variability is found to be driven predominantly by temperature, with the impact of precipitation being of secondary importance. In the central plateau, however, temperature and precipitation factors are equally important in modulating the interannual vegetation variability.

Possible functions of transmitter-controlled plateau potentials in α motoneurones

DEFF Research Database (Denmark)

Eken, T.; Hultborn, H.; Kiehn, O.

1989-01-01

are responsible for this bistable firing property in intact animals. The role of plateau potentials in locomotion is difficult to study. At present there are no clear indications of the utilization of plateau potentials in locomotion in intact animals. However, “clamped frequency” bursts which are observed...... in α motoneurones in reduced preparations is described. Thereafter we present some new data on a bistable behaviour in motor units in unrestrained intact animals during posture. Finally, the possible role of motoneuronal bistability in locomotion and in spasticity is discussed. Recently a bistable...... consequences of a bistable firing behaviour in the intact animal, the firing pattern of individual soleus motor units was studied by means of chronic EMG registration in awake unrestrained rats during quiet standing. Implanted electrodes allowed the delivery of excitatory and inhibitory stimulus trains...

The fractional acoustoelectric current plateau induced by the energy-dependent tunnelling from dynamic quantum dots into an impurity dot

Science.gov (United States)

Chen, S. W.; Song, L.

2016-08-01

The fractional acoustoelectric (AE) current plateau in surface-acoustic-waves (SAW) single-electron transport devices is studied by measuring the current plateau as a function of the SAW power and gate bias as well as a function of perpendicular magnetic filed. Our investigation indicates that the fractional plateau is induced by the tunnelling effect from the dynamic quantum dots (QDs) into a static impurity dot. Rate equations are used to extract the tunnelling rates, which change a lot with the number of electrons in the dynamic QDs, the SAW power and gate bias. In addition, the current plateau evolves into a fractional structure, when a strong perpendicular magnetic field is applied to the system.

Fast Oxidation Processes in a Naturally Reduced Aquifer Zone Caused by Dissolved Oxygen

Science.gov (United States)

Davis, J. A.; Jemison, N. E.; Williams, K. H.; Hobson, C.; Bush, R. P.

2014-12-01

The occurrence of naturally reduced zones is quite common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. The naturally reduced zones are heterogeneously dispersed in such aquifers and are characterized by high concentrations of organic carbon and reduced phases, including iron sulfides and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases that are found in association with these natural reducing zones, although there is little understanding of the relative importance of various potential oxidants. Three field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO wherein groundwater associated with naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in these field systems if supplied to the naturally reduced zones. Small concentrations of nitrate were also observed in the previously nitrate-free groundwater, and Fe(II) decreased to the detection limit. These results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS) rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table, and seasonal variations

Surface hydrologic investigations of the Columbia Plateau Region, Washington

International Nuclear Information System (INIS)

Leonhart, L.S.

1979-07-01

The Washington State portion of the Columbia Plateau is divided into six hydrologic sub-basins on the basis of the principal surface drainage systems present, structural and topographic relationships, and political and other considerations. Baseline descriptions of the surface water systems and resources are presented for the Columbia Plateau with emphasis on the Pasco Sub-basin. A preliminary evaluation of the hydrologic budget for each sub-basin is derived. For each sub-basin, recharge/discharge relationships arising from precipitation/evapotranspiration/runoff, stream losses and gains, and artificial mechanisms are determined on the basis of available data. The net exchange between surface and groundwater systems is evaluated and relative estimates of the net groundwater flow into or out of the sub-basin are obtained. An evaluation is made of hydrologic risk factors arising from: (1) tributary flooding in eastern Washington; and, (2) major flooding of the Columbia River within the Pasco Sub-basin. Scenarios are presented for credible natural and man-generated catastrophic events

Surface hydrologic investigations of the Columbia Plateau region, Washington

International Nuclear Information System (INIS)

Leonhart, L.S.

1979-01-01

The Washington State portion of the Columbia Plateau is divided into six hydrologic sub-basins on the basis of the principal surface drainage systems present, structural and topographic relationships, and political and other considerations. Baseline descriptions of the surface water systems and resources are presented for the Columbia Plateau with emphasis on the Pasco Sub-basin. A preliminary evaluation of the hydrologic budget for each sub-basin is derived. For each sub-basin, recharge/discharge relationships arising from precipitation/evapotranspiration/runoff, stream losses and gains, and artificial mechanisms are determined on the basis of available data. The net exchange between surface and ground-water systems is evaluated and relative estimates of the net ground-water flow into or out of the sub-basin are obtained. An evaluation is made of hydrologic risk factors arising from: (1) tributary flooding in eastern Washington; and (2) major flooding of the Columbia River within the Pasco Sub-basin. Scenarios are presented for credible natural and man-generated catastrophic events

Phased uplift of the northeastern Tibetan Plateau inferred from a pollen record from Yinchuan Basin, northwestern China.

Science.gov (United States)

Li, Xinling; Hao, Qingzhen; Wei, Mingjian; Andreev, Andrei A; Wang, Junping; Tian, Yanyan; Li, Xiaolei; Cai, Maotang; Hu, Jianmin; Shi, Wei

2017-12-21

The uplift of the Tibetan Plateau (TP) significantly affected both regional and global climates. Although there is evidence that the Tibetan Plateau experienced uplift during the Quaternary, the timing and amplitude are poorly constrained. However, the increased availability of long sedimentary records of vegetation change provides an opportunity to reconstruct the timing of the uplift. Here, we present a well-dated, high-resolution pollen record for the last 2.6 Ma from the Yinchuan Basin, which was incised by the Yellow River with its source in the northeastern Tibetan Plateau. Variations in the Artemisia/Chenopodiaceae (A/C) ratio of the reveal changes in moisture conditions in the Yinchuan Basin during glacial-interglacial cycles, as well as a gradual long-term aridification trend which is consistent with progressive global cooling. However, fluctuations in the percentages of Picea and Abies differ from those of the A/C ratio and we propose that they reflect changes in the vegetation and environment of high elevation areas. The Picea and Abies records reveal two phases of increased representation, at 2.1 and 1.2 Ma, which may indicate phases in the uplift of the northeastern Tibetan Plateau. Thus, they provide independent evidence for the timing of the uplift of the Tibetan Plateau during the Quaternary.

Contrast of lithospheric dynamics across the southern and eastern margins of the Tibetan Plateau: a numerical study

Science.gov (United States)

Sun, Yujun; Fan, Taoyuan; Wu, Zhonghai

2018-05-01

Both of the southern and eastern margins of the Tibetan Plateau are bounded by the cratonic blocks (Indian plate and Sichuan basin). However, there are many differences in tectonic deformation, lithospheric structure and surface heat flow between these two margins. What dynamics cause these differences? With the constraints of the lithospheric structure and surface heat flow across the southern and eastern margins of Tibetan Plateau, we constructed 2-D thermal-mechanical finite-element models to investigate the dynamics across these two margins. The results show that the delamination of mantle lithosphere beneath the Lhasa terrane in Oligocene and the rheological contrast between the Indian and Tibetan crust are the two main factors that control the subduction of the Indian plate. The dynamics across the eastern margin of the Tibetan Plateau are different from the southern margin. During the lateral expansion of the Tibetan Plateau, pure shear thickening is the main deformation characteristic for the Songpan-Ganzi lithosphere. This thickening results in the reduction of geothermal gradient and surface heat flow. From this study, it can be seen that the delamination of the mantle lithosphere and the rheological contrast between the Tibetan Plateau and its bounding blocks are the two main factors that control the lithospheric deformation and surface heat flow.

External fixation combined with delayed internal fixation in treatment of tibial plateau fractures with dislocation.

Science.gov (United States)

Tao, Xingguang; Chen, Nong; Pan, Fugen; Cheng, Biao

2017-10-01

The aim of this study was to evaluate the clinical efficacy of external fixation, delayed open reduction, and internal fixation in treating tibial plateau fracture with dislocation.Clinical data of 34 patients diagnosed with tibial plateau fracture complicated with dislocation between January 2009 and May 2015 were retrospectively analyzed. Fifteen patients in group A underwent early calcaneus traction combined with open reduction and internal fixation and 19 in group B received early external fixation combined with delayed open reduction and internal fixation. Operation time, postoperative complication, bone healing time, knee joint range of motion, initial weight-bearing time, Rasmussen tibial plateau score, and knee function score (HSS) were statistically compared between 2 groups.The mean follow-up time was 18.6 months (range: 5-24 months). The mean operation time in group A was 96 minutes, significantly longer than 71 minutes in group B (P  .05). In group A, initial weight-bearing time in group A was (14.0 ± 3.6) weeks, significantly differing from (12.9 ± 2.8) weeks in group B (P  0.05). Rasmussen tibial plateau score in group A was slightly lower than that in group B (P > .05). The excellent rate of knee joint function in group A was 80% and 84.21% in group B (P > .05).External fixation combined with delayed open reduction and internal fixation is a safer and more efficacious therapy of tibial plateau fracture complicated with dislocation compared with early calcaneus traction and open reduction and internal fixation.

Brain blood flow studies with single photon emission computed tomography in patients with plateau waves

International Nuclear Information System (INIS)

Hayashi, Minoru; Kobayashi, Hidenori; Kawano, Hirokazu; Handa, Yuji; Noguchi, Yoshiyuki; Shirasaki, Naoki; Hirose, Satoshi

1986-01-01

The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem : a cross section 25 deg over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves. (author)

Patterns of species diversity and phylogenetic structure of vascular plants on the Qinghai-Tibetan Plateau.

Science.gov (United States)

Yan, Yujing; Yang, Xian; Tang, Zhiyao

2013-11-01

Large-scale patterns of species richness and the underlying mechanisms regulating these patterns have long been the central issues in biogeography and macroecology. Phylogenetic community structure is a result of combined effects of contemporary ecological interactions, environmental filtering, and evolutionary history, and it links community ecology with biogeography and trait evolution. The Qinghai-Tibetan Plateau provides a good opportunity to test the influence of contemporary climate on shaping species richness because of its unique geological history, cold climate, and high biodiversity. In this study, based on high-resolution distributions of ˜9000 vascular plant species, we explored how species richness and phylogenetic structure of vascular plants correlate with climates on the highest (and species rich) plateau on the Earth. The results showed that most of the vascular plants were distributed on the eastern part of the plateau; there was a strong association between species richness and climate, even after the effects of habitat heterogeneity were controlled. However, the responses of richness to climate remarkably depended on life-forms. Richness of woody plants showed stronger climatic associations than that of herbaceous plants; energy and water availability together regulated richness pattern of woody plants; whereas water availability predominantly regulated richness pattern of herbaceous plants. The phylogenetic structure of vascular species clustered in most areas of the plateau, suggesting that rapid speciation and environment filtering dominated the assembly of communities on the plateau. We further propose that biodiversity conservation in this area should better take into account ecological features for different life-forms and phylogenetic lineages.

Phosphorus and Defoliation Interact and Improve the Growth and Composition of the Plant Community and Soil Properties in an Alpine Pasture of Qinghai-Tibet Plateau.

Science.gov (United States)

Qi, Juan; Nie, Zhongnan; Jiao, Ting; Zhang, Degang

2015-01-01

Pasture degradation caused by overgrazing and inappropriate fertiliser management is a major production and environmental threat in Qinghai-Tibet Plateau. Previous research has focused on the effects of mixed nitrogen (N) and phosphorus (P) fertiliser and reduced grazing pressure on the plant community of the grassland; however, the role of P and how it interacts with various defoliation (the process of the complete or partial removal of the above-ground parts of plants by grazing or cutting) intensities on the plant and soil of the grassland ecosystem have not been quantified. A field experiment was conducted to quantify how P application in combination of defoliation pressure could impact the dynamic change of the plant and soil in a native alpine grassland ecosystem of the Qinghai-Tibet Plateau, China, from May 2012 to September 2014. A split-plot design with 4 replicates and repeated measures was used to determine the growth and composition of plant community and soil physical and chemical properties under various levels of P fertiliser and defoliation intensity. The results showed that applying 20 kg P/ha increased the herbage yield of Melissitus ruthenica by 68% and total pasture yield by 25%. Close defoliation favoured the growth and plant frequency of the shorter species, whereas lax defoliation favoured that of the taller plant species. Medium P rate and cutting to 3 cm above ground gave an overall best outcome in pasture yield, quality and frequency and soil moisture and nutrient concentration. Application of P fertiliser with a moderate defoliation pressure to promote legume growth and N fixation has the potential to achieve multiple benefits in increasing pasture and livestock production and improving environmental sustainability in the alpine pasture of Qinghai-Tibet Plateau, a fragile and P-deficient ecosystem zone in China and its western neighbouring countries.

Combining CHAMP and Swarm Satellite Data to Invert the Lithospheric Magnetic Field in the Tibetan Plateau.

Science.gov (United States)

Qiu, Yaodong; Wang, Zhengtao; Jiang, Weiping; Zhang, Bingbing; Li, Fupeng; Guo, Fei

2017-01-26

CHAMP and Swarm satellite magnetic data are combined to establish the lithospheric magnetic field over the Tibetan Plateau at satellite altitude by using zonal revised spherical cap harmonic analysis (R-SCHA). These data are integrated with geological structures data to analyze the relationship between magnetic anomaly signals and large-scale geological tectonic over the Tibetan Plateau and to explore the active tectonic region based on the angle of the magnetic anomaly. Results show that the model fitting error is small for a layer 250-500 km high, and the RMSE of the horizontal and radial geomagnetic components is better than 0.3 nT. The proposed model can accurately describe medium- to long-scale lithospheric magnetic anomalies. Analysis indicates that a negative magnetic anomaly in the Tibetan Plateau significantly differs with a positive magnetic anomaly in the surrounding area, and the boundary of the positive and negative regions is generally consistent with the geological tectonic boundary in the plateau region. Significant differences exist between the basement structures of the hinterland of the plateau and the surrounding area. The magnetic anomaly in the Central and Western Tibetan Plateau shows an east-west trend, which is identical to the direction of the geological structures. The magnetic anomaly in the eastern part is arc-shaped and extends along the northeast direction. Its direction is significantly different from the trend of the geological structures. The strongest negative anomaly is located in the Himalaya block, with a central strength of up to -9 nT at a height of 300 km. The presence of a strong negative anomaly implies that the Curie isotherm in this area is relatively shallow and deep geological tectonic activity may exist.

Satellite remote sensing of the island mass effect on the Sub-Antarctic Kerguelen Plateau, Southern Ocean

Science.gov (United States)

Jena, Babula

2016-09-01

The presence of the Kerguelen Plateau and surrounding bathymetric features has a strong influence on the persistently eastward flowing Antarctic Circumpolar Current (ACC), resulting in enhancement of surface chlorophyll-a (Chl- a) in the downstream section of the plateau along the polar front (PF). The phenomenon is reported in this paper as the island mass effect (IME). Analysis of climatological Chl- a datasets from Aqua- Moderate Resolution Imaging Spectroradiometer (Aqua- MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) shows distinct bloomy plumes (Chl- a>0.5 mg/m3) during austral spring-summer spreading as far as ~1800 km offshore up to 98°E along the downstream of the north Kerguelen Plateau (NKP). Similar IME phenomena is apparent over the south Kerguelen Plateau (SKP) with the phytoplankton bloom extending up to 96.7°E, along the southern boundary of ACC. The IME phenomena are pronounced only during austral spring-summer period with the availability of light and sedimentary source of iron from shallow plateau to sea surface that fertilizes the mixed layer. The NKP bloom peaks with a maximum areal extent of 1.315 million km2 during December, and the SKP bloom peaks during January with a time lag of one month. The blooms exist for at least 4 months of a year and are significant both as the base of regional food web and for regulating the biogeochemical cycle in the Southern Ocean. Even though the surface water above the Kerguelen Plateau is rich in Chl- a, an exception of an oligotrophic condition dominated between NKP and SKP due to apparent intrusion of iron limited low phytoplankton regime waters from the Enderby basin through the northeastward Fawn Trough Current.

The expression of Ldh-c in the skeletal muscle of plateau pika (Ochotona curzoniae enhances adaptation to a hypoxic environment

Directory of Open Access Journals (Sweden)

Zhi F. An

2017-09-01

Full Text Available The plateau pika (Ochotona curzoniae is a species of sprint-running alpine animals in the Qinghai-Tibet Plateau, which is a harsh highland hypoxic environment. Ldh-c is expressed in the testis, sperm and somatic tissues of plateau pika. To reveal the role and physiological mechanisms of sperm-specific lactate dehydrogenase (LDH-C4, in plateau pika to adapt to hypoxic environment, an adenoviral line of pMultiRNAi-Ldhc was constructed and injected into the bilateral biceps femoris of the hind legs. The swimming times of the pikas, and the Ldh-c expression levels, total LDH activities and ATP levels in skeletal muscle, were measured after the pikas were raised in the trapped site for 5 days. Our results showed that after Ldh-c was silenced, the sprint-running ability (swimming time of the plateau pikas was significant decreased, and the total LDH activities and ATP levels were reduced by 28.21% and 27.88%, respectively. Our results indicated that expression of Ldh-c in the skeletal muscle of plateau pika increased anaerobic glycolysis and enhanced adaptation to highland hypoxic environments.

Predicting the distribution of Stipa purpurea across the Tibetan Plateau via the MaxEnt model.

Science.gov (United States)

Ma, Baibing; Sun, Jian

2018-02-21

The ecosystems across Tibetan Plateau are changing rapidly under the influence of climate warming, which has caused substantial changes in spatial and temporal environmental patterns. Stipa purpurea, as a dominant herbsage resource in alpine steppe, has a great influence on animal husbandry in the Tibetan Plateau. Global warming has been forecasted to continue in the future (2050s, 2070s), questioning the future distribution of S. purpurea and its response to climate change. The maximum entropy (MaxEnt) modeling, due to its multiple advantages (e.g. uses presence-only data, performs well with incomplete data, and requires small sample sizes and gaps), has been used to understand species environment relationships and predict species distributions across locations that have not been sampled. Annual mean temperature, annual precipitation, temperature seasonality, altitude, and precipitation during the driest month, significantly affected the distribution of S. purpurea. Only 0.70% of the Tibetan Plateau area included a very highly suitable habitat (habitat suitability [HS] = 0.8-1.0). Highly suitable habitat (HS = 0.6-0.8), moderately suitable habitat (HS = 0.4-0.6), and unsuitable habitat (HS = 0.2-0.4) occupied 6.20, 14.30 and 22.40% of the Tibetan Plateau area, respectively, and the majority (56.40%) of the Tibetan Plateau area constituted a highly unsuitable habitat (HS = 0-0.2). In addition, the response curves of species ecological suitability simulated by generalized additive model nearly corresponded with the response curves generated by the MaxEnt model. At a temporal scale, the habitat suitability of S. purpurea tends to increase from the 1990s to 2050s, but decline from the 2050s to 2070s. At a spatial scale, the future distribution of S. purpurea will not exhibit sweeping changes and will remain in the central and southeastern regions of the Tibetan Plateau. These results benefit the local animal husbandry and provide evidence for establishing

Evaluating groundwater recharge variations under climate change in an endorheic basin of the Andean plateau

Science.gov (United States)

Blin, N.; Hausner, M. B.; Suarez, F. I.

2017-12-01

In arid and semi-arid regions, where surface water and precipitations are scarce, groundwater is the main source of drinking water that sustains human and natural ecosystems. Therefore, it is very important to consider the potential impacts of climate change that threaten the availability of this resource. The purpose of this study is to investigate the variations caused by climate change on the recharge of the regional groundwater aquifer at the Huasco salt flat, located in the Chilean Andean plateau. The Huasco salt flat basin has ecosystems sustained by wetlands that depend on the groundwater levels of this aquifer. Due to this reason, the Chilean government has declared this zone as protected. Hence, the assurance of the future availability of the groundwater resource becomes extremely important. The sustainable management of this resource requires reasonable estimates of recharge and evapotranspiration, which are highly dependent on the characteristics and processes occurring in the vadose zone, i.e., topography, soil type and land use, and their temporal and spatial variations are significant in arid regions. With this aim, a three-dimensional groundwater model, implemented in SWAT-MODFLOW, was developed to couple the saturated system with the vadose zone. The model was calibrated and validated using historic data. General circulation models (GCMs) were used as scenarios inputs of recharge to the groundwater model. Future simulations were run by applying an offset to the historic air temperatures and to the precipitation. These offsets were determined using a delta hybrid approach based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble archive. The obtained results were downscaled to the 0.125º latitude x 0.125º longitude grid cell containing the basin of the Huasco salt flat. The hybrid approach considered the 10th, 50th and 90th percentiles of the projected temperature and precipitation output as three scenarios of climate

Spatial variation and driving factors of soil moisture at multi-scales: a case study in Loess Plateau of China

Science.gov (United States)

Zhao, W.; Zhang, X.; Liu, Y.; Fang, X.

2017-12-01

Currently, the ecological restoration of the Loess Plateau has led to significant achievements such as increases in vegetation coverage, decreases in soil erosion, and enhancement of ecosystem services. Soil moisture shortages, however, commonly occur as a result of limited rainfall and strong evaporation in this semiarid region of China. Since soil moisture is critical in regulating plant growth in these semiarid regions, it is crucial to identify the spatial variation and factors affecting soil moisture at multi-scales in the Loess Plateau of China. In the last several years, extensive studies on soil moisture have been carried out by our research group at the plot, small watershed, watershed, and regional scale in the Loess Plateau, providing some information for vegetation restoration in the region. The main research results are as follows: (1) the highest soil moisture content was in the 0-0.1 m layer with a large coefficient of variation; (2) in the 0-0.1m layer, soil moisture content was negatively correlated with relative elevation, slope and vegetation cover, the correlations among slope, aspect and soil moisture increased with depth increased; (3) as for the deep soil moisture content, the higher spatial variation of deep SMC occurred at 1.2-1.4 m and 4.8-5.0m; (4) the deep soil moisture content in native grassland and farmland were significant higher than that of introduced vegetation; (5) at regional scale, the soil water content under different precipitation zones increased following the increase of precipitation, while, the influencing factors of deep SMC at watershed scale varied with land management types; (6) in the areas with multi-year precipitation of 370 - 440mm, natural grass is more suitable for restoration, and this should be treated as the key areas in vegetation restoration; (7) appropriate planting density and species selection should be taken into account for introduced vegetation management; (8) it is imperative to take the local

Seasonal dynamics of the tick Haemaphysalis tibetensis in the Tibetan Plateau, China.

Science.gov (United States)

Liu, M; Li, T; Yu, Z J; Qiu, Z X; Yan, P; Li, Y; Liu, J

2017-12-01

The tick Haemaphysalis tibetensis (Acari: Ixodidae) Hoogstraal is an important arthropod vector widespread in the Qinghai-Tibet Plateau, and knowledge of its seasonal dynamics is still poor. The current study investigated the seasonal dynamics of the parasitic and non-parasitic H. tibetensis over a 2-year period from March 2014 to February 2016 in the Tibetan Plateau, China. During this timeframe, non-parasitic ticks were collected weekly by flag-dragging in grassland and shrubland areas, and parasitic ticks were removed weekly from selected sheep. Plateau pikas were captured using traps and examined for immature ticks between May to September 2014. Results suggest that non-parasitic H. tibetensis were mainly distributed in the grassland, and the parasitic adults and nymphs were found mostly on sheep. Larvae were usually found on Plateau pikas and the prevalence of infestation and mean parasitic intensity were 72.1 and 1.81%, respectively. Adults were observed from March to July with the major peak occurring in mid-April. Nymphs were found from March to August and reached a peak in late June. Larvae were collected from April to September, and their numbers peaked in late May. In the parasitic and non-parasitic period, the overall sex ratio of males to females was 1.62 and 1.30, respectively. Results show that H. tibetensis can complete one generation per year, with a population overlap between stages over the spring-summer months. These findings provide additional information on the biology and ecology of H. tibetensis as well as insights on its control in the environment and on sheep. © 2017 The Royal Entomological Society.

Relationships between climate and growth of Gymnocypris selincuoensis in the Tibetan Plateau.

Science.gov (United States)

Tao, Juan; Chen, Yifeng; He, Dekui; Ding, Chengzhi

2015-04-01

The consequences of climate change are becoming increasingly evident in the Tibetan Plateau, represented by glaciers retreating and lakes expanding, but the biological response to climate change by plateau-lake ecosystems is poorly known. In this study, we applied dendrochronology methods to develop a growth index chronology with otolith increment widths of Selincuo naked carp (Gymnocypris selincuoensis), which is an endemic species in Lake Selincuo (4530 m), and investigated the relationships between fish growth and climate variables (regional and global) in the last three decades. A correlation analysis and principle component regression analysis between regional climate factors and the growth index chronology indicated that the growth of G. selincuoensis was significantly and positively correlated with length of the growing season and temperature-related variables, particularly during the growing season. Most of global climate variables, which are relevant to the Asian monsoon and the midlatitude westerlies, such as El Nino Southern Oscillation Index, the Arctic Oscillation, North Atlantic Oscillation, and North America Pattern, showed negative but not significant correlations with the annual growth of Selincuo naked carp. This may have resulted from the high elevation of the Tibetan Plateau and the high mountains surrounding this area. In comparison, the Pacific Decade Oscillation (PDO) negatively affected the growth of G. selincuoensis. The reason maybe that enhancement of the PDO can lead to cold conditions in this area. Taken together, the results indicate that the Tibetan Plateau fish has been affected by global climate change, particularly during the growing season, and global climate change likely has important effects on productivity of aquatic ecosystems in this area.

Breaking the spiral of unsustainability : an exploratory land use study for Ansai, the Loess Plateau of China

NARCIS (Netherlands)

Lu, C.

2000-01-01

Serious soil loss, food insecurity, population pressure, and low income of the rural population are interrelated, and consequently result in a spiral of unsustainability in the Loess Plateau, China. This thesis takes Ansai County in the Loess Plateau of China as a case study, to explore

The Application of Chaos Theory to the Career-Plateaued Worker.

Science.gov (United States)

Duffy, Jean Ann

2000-01-01

Applies some of the principles of chaos theory to career-plateaued workers on the basis of a case study. Concludes that chaos theory provides career practitioners a useful application for working with this type of client. (Author/JDM)

IODP Expedition 324: Ocean Drilling at Shatsky Rise Gives Clues about Oceanic Plateau Formation

Directory of Open Access Journals (Sweden)

Jörg Geldmacher

2011-09-01

Full Text Available Integrated Ocean Drilling Program (IODP Expedition 324 cored Shatsky Rise at five sites (U1346–U1350 to study processes of oceanic plateau formation and evolution. Site penetrations ranged from 191.8 m to 324.1 m with coring of 52.6 m to 172.7 m into igneous basement at four of the sites. Average recovery in basement was 38.7%–67.4%. Cored igneous sections consist mainly of variably evolved tholeiiticbasalts emplaced as pillows or massive flows. Massive flows are thickest and make up the largest percentage of section on the largest and oldest volcano, late Jurassic age Tamu Massif; thus, it may have formed at high effusion rates. Such massive flows are characteristic of flood basalts, and similar flows were cored at Ontong Java Plateau. Indeed, the similarity of igneous sections at Site U1347 with that cored on Ontong Java Plateau implies similar volcanic styles for these two plateaus. On younger, smaller Shatsky Rise volcanoes, pillow flows are common and massive flows thinner andfewer, which might mean volcanism waned with time. Cored sediments from summit sites contain fossils and structures implying shallow water depths or emergence at the time of eruption and normal subsidence since. Summit sites also show pervasive alteration that could be due to high fluid fluxes. A thick section of volcaniclastics cored on Tamu Massif suggests that shallow, explosive submarine volcanism played a significant role in the geologic development of the plateau summit. Expedition 324 results imply that Shatsky Risebegan with massive eruptions forming a huge volcano and that subsequent eruptions waned in intensity, forming volcanoes that are large, but which did not erupt with unusually high effusionrates. Similarities of cored sections on Tamu Massif with those ofOntong Java Plateau indicate that these oceanic plateaus formed insimilar fashion.

Threshold friction velocity of soils within the Columbia Plateau

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Wind erosion only occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. The TFV of loessial soils commonly found across the Columbia Plateau region of the U.S. Pacific Northwest is virtually unknown even though these soils are highly erodible and a source of...

Influence of environmental factors on spectral characteristic of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China

Science.gov (United States)

Wen, Z. D.; Song, K. S.; Zhao, Y.; Du, J.; Ma, J. H.

2015-06-01

Spectral characteristics of chromophoric dissolved organic matter (CDOM) were examined in conjunction with environmental factors in the waters of 22 rivers and 26 terminal waters in Hulun Buir plateau, northeast China. Dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorous (TP) were significantly higher in terminal waters than rivers waters (p CDOM absorption in river waters was significantly lower than terminal waters (p CDOM in river waters had higher aromaticity, molecular weight, and vascular plant contribution than in terminal waters. Furthermore, results showed that DOC concentration, CDOM light absorption, and the proportion of autochthonous sources of CDOM in plateau waters were all higher than in other freshwater rivers reported in the literature. The strong evapoconcentration, intense ultraviolet irradiance and landscape features of Hulun Buir plateau may be responsible for the above phenomenon. Redundancy analysis (RDA) indicated that the environmental variables TSM, TN, and EC had a strong correlation with light absorption characteristics, followed by TDS and chlorophyll a. In most sampling locations, CDOM was the dominant non-water light-absorbing substance. Light absorption by non-algal particles often exceeded that by phytoplankton in the plateau waters. Study of these optical-physicochemical correlations is helpful in the evaluation of the potential influence of water quality factors on non-water light absorption in cold plateau water environments. And the study on organic carbon in plateau lakes had a vital contribution to global carbon balance estimation.

Differences in inhibition by beta-arabinofuranosyladenine (araA) of radiation induced DNA damage repair in exponentially growing and plateau-phase CHO-cells

International Nuclear Information System (INIS)

Iliakis, G.; Seaner, R.

1988-01-01

The effect of beta-arabinofuranosyladenine (araA) on the repair of radiation induced DNA damage, as measured by the DNA unwinding technique, was studied in exponentially growing and plateau-phase CHO-cells after exposure to X-rays. Induction of DNA damage by radiation was found to be similar in exponentially growing and plateau-phase cells. In the absence of araA, repair of radiation induced DNA damage proceeded with similar kinetics in exponentially growing and plateau-phase cells. AraA at concentrations between 0-1500 μM inhibited DNA repair both in exponentially growing and in plateau-phase cells. However, the degree of inhibition was significantly higher (by a factor of 3) in plateau-phase cells. A similar degree of repair inhibition by araA was observed in plateau-phase cells treated in their conditioned medium, as well as in plateau-phase cells that were transferred in fresh growth medium just before treatment initiation. These results indicate the importance of biochemical parameters associated with alterations in the growth state of the cells for the inhibitory effect of araA and may help in the elucidation of the molecular mechanism(s) underlying repair inhibition by inhibitors of DNA replication. (orig.)

Banana fluxes in the plateau regime for a nonaxisymmetrically confined plasma

International Nuclear Information System (INIS)

Balescu, R.; Fantechi, S.

1990-01-01

The banana (or banana-plateau) fluxes, related to the generalized stresses left-angle B·∇·π α(n) right-angle, left-angle B T ·∇·π α(n) right-angle have been determined in the plateau regime, for a plasma confined by a toroidal magnetic field of arbitrary geometry. The complete set of transport coefficients for both the ''parallel'' (ambipolar) and ''toroidal'' (nonambipolar) banana fluxes was obtained in the 13-moment (13M) approximation, going beyond the previously known expressions in the nonaxisymmetric case. The main emphasis is laid on the structure of the transport matrix and of its coefficients. It is shown that the Onsager symmetry of this matrix partly breaks down (for the mixed electron--ion coefficients) in a nonaxisymmetrically confined plasma

Geologic field-trip guide to the volcanic and hydrothermal landscape of the Yellowstone Plateau

Science.gov (United States)

Morgan Morzel, Lisa Ann; Shanks, W. C. Pat; Lowenstern, Jacob B.; Farrell, Jamie M.; Robinson, Joel E.

2017-11-20

Yellowstone National Park, a nearly 9,000 km2 (~3,468 mi2) area, was preserved in 1872 as the world’s first national park for its unique, extraordinary, and magnificent natural features. Rimmed by a crescent of older mountainous terrain, Yellowstone National Park has at its core the Quaternary Yellowstone Plateau, an undulating landscape shaped by forces of late Cenozoic explosive and effusive volcanism, on-going tectonism, glaciation, and hydrothermal activity. The Yellowstone Caldera is the centerpiece of the Yellowstone Plateau. The Yellowstone Plateau lies at the most northeastern front of the 17-Ma Yellowstone hot spot track, one of the few places on Earth where time-transgressive processes on continental crust can be observed in the volcanic and tectonic (faulting and uplift) record at the rate and direction predicted by plate motion. Over six days, this field trip presents an intensive overview into volcanism, tectonism, and hydrothermal activity on the Yellowstone Plateau (fig. 1). Field stops are linked directly to conceptual models related to monitoring of the various volcanic, geochemical, hydrothermal, and tectonic aspects of the greater Yellowstone system. Recent interest in young and possible future volcanism at Yellowstone as well as new discoveries and synthesis of previous studies, (for example, tomographic, deformation, gas, aeromagnetic, bathymetric, and seismic surveys), provide a framework in which to discuss volcanic, hydrothermal, and seismic activity in this dynamic region.

Thorium abundances on the aristarchus plateau: Insights into the composition of the aristarchus pyroclastic glass deposits

Science.gov (United States)

Hagerty, Justin J.; Lawrence, D.J.; Hawke, B.R.; Gaddis, Lisa R.

2009-01-01

Thorium (Th) data from the Lunar Prospector gamma ray spectrometer (LP-GRS) are used to constrain the composition of lunar pyroclastic glass deposits on top of the Aristarchus plateau. Our goal is to use forward modeling of LP-GRS Th data to measure the Th abundances on the plateau and then to determine if the elevated Th abundances on the plateau are associated with the pyroclastic deposits or with thorium-rich ejecta from Aristarchus crater. We use a variety of remote sensing data to show that there is a large, homogenous portion of the pyroclastics on the plateau that has seen little or no contamination from the Th-rich ejecta of Aristarchus crater. Our results show that the uncontaminated pyroclastic glasses on Aristarchus plateau have an average Th content of 6.7 ppm and ???7 wt % TiO2. These Th and Ti values are consistent with Th-rich, intermediate-Ti yellow glasses from the lunar sample suite. On the basis of this information, we use petrologic equations and interelement correlations for the Moon to estimate the composition of the source region from which the Aristarchus glasses were derived. We find that the source region for the Aristarchus glasses contained high abundances of heat-producing elements, which most likely served as a thermal driver for the prolonged volcanic activity in this region of the Moon. Copyright 2009 by the American Geophysical Union.

On the reproducibility of apatite fission-track plateau-age dating

International Nuclear Information System (INIS)

Poupeau, G.; Baitelli, R.; Berbert, M.; Fonseca, A.

1985-01-01

Duplicate measurements as well as published data show that plateau-age measurements on apatites have a reproducibility - when made in optical microscopy - generally better than +- 5%, which may be accounted for by statistical errors on track density measurement. (Author) [pt

Molecular identification of Taenia mustelae cysts in subterranean rodent plateau zokors (Eospalax baileyi).

Science.gov (United States)

Zhao, Fang; Ma, Jun-Ying; Cai, Hui-Xia; Su, Jian-Ping; Hou, Zhi-Bin; Zhang, Tong-Zuo; Lin, Gong-Hua

2014-07-01

Cestode larvae spend one phase of their two-phase life cycle in the viscera of rodents, but cases of cestodes infecting subterranean rodents have only been rarely observed. To experimentally gain some insight into this phenomenon, we captured approximately 300 plateau zokors (Eospalax baileyi), a typical subterranean rodent inhabiting the Qinghai-Tibet Plateau, and examined their livers for the presence of cysts. Totally, we collected five cysts, and using a mitochondrial gene (cox1) and two nuclear genes (pepck and pold) as genetic markers, we were able to analyze the taxonomy of the cysts. Both the maximum likelihood and Bayesian methods showed that the cysts share a monophyly with Taenia mustelae, while Kimura 2-parameter distances and number of different sites between our sequences and T. mustelae were far less than those found between the examined sequences and other Taeniidae species. These results, alongside supporting paraffin section histology, imply that the cysts found in plateau zokors can be regarded as larvae of T. mustelae, illustrating that zokors are a newly discovered intermediate host record of this parasite.

Aerosol vertical distribution characteristics over the Tibetan Plateau

International Nuclear Information System (INIS)

Deng, Z Q; Han, Y X; Zhao, Q; Li, J

2014-01-01

The Stratospheric Aerosol and Gas Experiment II (SAGE II) aerosol products are widely used in climatic characteristic studies and stratospheric aerosol pattern research. Some SAGE II products, e.g., temperature, aerosol surface area density, 1020 nm aerosol extinction coefficient and dust storm frequency, from ground-based observations were analysed from 1984 to 2005. This analysis explored the time and spatial variations of tropospheric and stratospheric aerosols on the Tibet Plateau. The stratospheric aerosol extinction coefficient increased more than two orders of magnitude because of a large volcanic eruption. However, the tropospheric aerosol extinction coefficient decreased over the same period. Removing the volcanic eruption effect, the correlation coefficient for stratospheric AOD (Aerosol Optical Depth) and tropospheric AOD was 0.197. Moreover, the correlation coefficient for stratospheric AOD and dust storm frequency was 0.315. The maximum stratospheric AOD was attained in January, the same month as the tropospheric AOD, when the Qaidam Basin was the centre of low tropospheric AOD and the large mountains coincided with high stratospheric AOD. The vertical structure generated by westerly jet adjustment and the high altitude of the underlying surface of the Tibetan Plateau were important factors affecting winter stratospheric aerosols

Seismic studies of crustal structure and tectonic evolution across the central California margin and the Colorado Plateau margin

Science.gov (United States)

Howie, John Mark

Poisson's ratio (0.20 plus or minus 0.05) in the middle crust probably indicates high quartz content. The presence of quartz in large amounts would make the middle crust rheologically weak. The localization of reflectivity within the middle crust probably results from a focusing of shear strain and magmatic intrusions in this rheologically weak zone. Lateral variation of reflectivity in the middle crust between the unextended and non-reflective Colorado Plateau and the extended and reflective Transition Zone illustrates the effect of Miocene and younger extensional tectonism on crustal reflectivity.

A longitudinal cline characterizes the genetic structure of human populations in the Tibetan plateau

Science.gov (United States)

Peter, Benjamin M.; Basnyat, Buddha; Neupane, Maniraj; Beall, Cynthia M.; Childs, Geoff; Craig, Sienna R.; Novembre, John; Di Rienzo, Anna

2017-01-01

Indigenous populations of the Tibetan plateau have attracted much attention for their good performance at extreme high altitude. Most genetic studies of Tibetan adaptations have used genetic variation data at the genome scale, while genetic inferences about their demography and population structure are largely based on uniparental markers. To provide genome-wide information on population structure, we analyzed new and published data of 338 individuals from indigenous populations across the plateau in conjunction with worldwide genetic variation data. We found a clear signal of genetic stratification across the east-west axis within Tibetan samples. Samples from more eastern locations tend to have higher genetic affinity with lowland East Asians, which can be explained by more gene flow from lowland East Asia onto the plateau. Our findings corroborate a previous report of admixture signals in Tibetans, which were based on a subset of the samples analyzed here, but add evidence for isolation by distance in a broader geospatial context. PMID:28448508

Heavy metals in the surface sediments of lakes on the Tibetan Plateau, China.

Science.gov (United States)

Guo, Bixi; Liu, Yongqin; Zhang, Fan; Hou, Juzhi; Zhang, Hongbo; Li, Chaoliu

2018-02-01

Heavy metal contamination has affected many regions in the world, particularly the developing countries of Asia. We investigated 8 heavy metals (Cu, Zn, Cd, Pb, Cr, Co, Ni, and As) in the surface sediments of 18 lakes on the Tibetan Plateau. It was found that the distributions of the heavy metals showed no clear spatial pattern on the plateau. The results indicated that the mean concentrations of these metals in the sediment samples diminished as follows: Cr > As > Zn > Ni > Pb > Cu > Co > Cd. The results of geoaccumulation index (I geo ) and potential ecological risk factor (E i r ) assessments showed that the sediments were moderately polluted by Cd and As, which posed much higher risks than the other metals. The values of the potential ecological risk index (RI) showed that lake Bieruoze Co has been severely polluted by heavy metals. Principal component analysis, hierarchical cluster analysis, and Pearson correlation analysis results indicated that the 8 heavy metals in the lake surface sediments of the Tibetan Plateau could be classified into four groups. Group 1 included Cu, Zn, Pb, Co, and Ni which were mainly derived from both natural and traffic sources. Group 2 included Cd which mainly originated from anthropogenic sources like alloying, electroplating, and dyeing industries and was transported to the Tibetan Plateau by atmospheric circulation. Group 3 included Cr and it might mainly generate from parent rocks of watersheds. The last Group (As) was mainly from manufacturing, living, and the striking deterioration of atmospheric environment of the West, Central Asia, and South Asia.

Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study.

Science.gov (United States)

Chen, Pengbo; Lu, Hua; Shen, Hao; Wang, Wei; Ni, Binbin; Chen, Jishizhan

2017-02-23

Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

A model of karst systems of the Usturt plateau (Middle Asia)

International Nuclear Information System (INIS)

Victorov, A. S.

2016-01-01

The issues relating to the structure and development of desert karst is currently one of the least studied problems. The goal of the research efforts presented in this paper was to create a model of karst systems in the Usturt Plateau and, primarily, of the systems formed by the prevailing numerous surface karst landforms. The model is based on the following main assumptions: the process of emergence of the karst phenomena is probabilistic and occurs independently at non-intersecting sites; the probability of emergence of one depression at a reference site depends only on its area. The increase of the dimensions of a karst landform is a random process that occurs independently of other karst landforms, its speed is governed by random factors, and it is directly proportionate to the existing dimensions of the landform. The model does not assume constancy of climatic characteristics. The testing was conducted at several reference sites of the Usturt Plateau. The research allowed us to reach the following conclusions: the karst depressions of the Usturt Plateau, which are the typical forms of desert karst, are governed by the Poisson distribution of their centres and by the lognormal distribution of their dimensions, similar to the karst depressions in a humid climate. The results may be used in assessments of karst hazard for linear and areal structures, as well as for small-dimensional structures. (Author)

[The pathogenesis of subclinical laminitis in dairy cattle: studies of the hoof status, rumen status and blood coagulation factors].

Science.gov (United States)

Brandejsky, F; Stanek, C; Schuh, M

1994-02-01

In 50 dairy cows of the breed "Braunvieh" (36 heifers, 14 cows) of one herd the claw score was recorded over a period of 2 months before parturition until 6 months after parturition. The claw scores were correlated with the clinical findings, the ruminal function and the blood coagulation factors calcium-thromboplastin (TPZ), partial thromboplastin time (PTT), thrombin time (TZ) and antithrombin III (AT III) evaluated one day and one week after calving. The claw score increased from the first to the second examination, remaining on the same level in the postpartal period. No correlation between the claw scores and the ruminal function was evident. In comparison with a control group, TPZ and PTT were found higher one day and one week after parturition in the experimental group. Blood coagulation factors and claw scores were found uncorrelated.

Numerical Simulation of Stress evolution and earthquake sequence of the Tibetan Plateau

Science.gov (United States)

Dong, Peiyu; Hu, Caibo; Shi, Yaolin

2015-04-01

The India-Eurasia's collision produces N-S compression and results in large thrust fault in the southern edge of the Tibetan Plateau. Differential eastern flow of the lower crust of the plateau leads to large strike-slip faults and normal faults within the plateau. From 1904 to 2014, more than 30 earthquakes of Mw > 6.5 occurred sequentially in this distinctive tectonic environment. How did the stresses evolve during the last 110 years, how did the earthquakes interact with each other? Can this knowledge help us to forecast the future seismic hazards? In this essay, we tried to simulate the evolution of the stress field and the earthquake sequence in the Tibetan plateau within the last 110 years with a 2-D finite element model. Given an initial state of stress, the boundary condition was constrained by the present-day GPS observation, which was assumed as a constant rate during the 110 years. We calculated stress evolution year by year, and earthquake would occur if stress exceed the crustal strength. Stress changes due to each large earthquake in the sequence was calculated and contributed to the stress evolution. A key issue is the choice of initial stress state of the modeling, which is actually unknown. Usually, in the study of earthquake triggering, people assume the initial stress is zero, and only calculate the stress changes by large earthquakes - the Coulomb failure stress changes (Δ CFS). To some extent, this simplified method is a powerful tool because it can reveal which fault or which part of a fault becomes more risky or safer relatively. Nonetheless, it has not utilized all information available to us. The earthquake sequence reveals, though far from complete, some information about the stress state in the region. If the entire region is close to a self-organized critical or subcritical state, earthquake stress drop provides an estimate of lower limit of initial state. For locations no earthquakes occurred during the period, initial stress has to be

KARSTIC GEOMORPHOSITES WITH HIGH TOURISTIC VALUE IN MEHEDINȚI PLATEAU

Directory of Open Access Journals (Sweden)

Mihaela Ioana IAMANDEI

2017-10-01

Full Text Available In the Mehedinţi Plateau area, there is a great number of karsts complexes, also named geomorphosites, created by the action of water in the massive calcareous rocks. Some of these, such as Izverna and Topolnita karsts complexes, are suitable to speleological tourism, cave diving, tourist and scientific explorations, underground and underwater photography and filming. Tourists come here from all over the world and this is a place where special camps for cave diving the fans are organized. This study presents especially the types of geomorphosites generated by water, the touristic offer in this area and the analysis of indicators representing the global value of one of the main geomorphosites. This global value increased in particular due to their scientific, cultural and aesthetic values which makes them suitable to ecotourism. The economic value is also an important indicator for the touristic activities in Mehedinți Plateau.

Observation and calculation of the solar radiation on the Tibetan Plateau

International Nuclear Information System (INIS)

Liu Jiandong; Liu Jingmiao; Linderholm, Hans W.; Chen Deliang; Yu Qiang; Wu Dingrong; Haginoya, Shigenori

2012-01-01

Highlights: ► Five years of continuous solar-radiation observations on the Tibetan Plateau were analyzed. ► Eight solar models were calibrated and validated in this highland region. ► A strategy for calculating solar radiation on the Tibetan Plateau was presented. - Abstract: Distribution of solar radiation is vital to locate the most suitable regions for harvesting solar energy, but solar radiation is only observed at few stations due to high costs and difficult maintenance. From 2001 to 2005, a set of pyranometer instruments were set up in Gaize, on the Tibetan Plateau, to test the hypothesis of high solar-radiation levels in this region, and find a suitable method for estimating the radiation. Over the 5-year observation period, the average daily radiation was 21 MJ m −2 day −1 with maximum daily values of 27 MJ m −2 day −1 occurring in June and minimum values of 14 MJ m −2 day −1 in December, which is much higher than those measured in other regions at similar latitudes. The observational data were used to validate a set of radiation models: five sunshine based and three temperature based. The results showed that of the five sunshine-based models, a newly developed “comprehensive” model performed the best, but that the “vapor revised Angstrom model” was recommended to use for its simplicity and easy operation. The temperature-based models performed worse than the sunshine-based ones, where the Wu model is to be preferred if a temperature-based model is the only option. Moreover, it was shown that when estimating the solar radiation based on time-dependent coefficients, consideration of the seasonal variation of the coefficients has little predictive value and is thus unnecessary. Based on the results of this study, a strategy for the calculation of solar radiation on the Tibetan Plateau was made for potential users.

Electromagnetically Inferred Structure of the Caja del Rio Plateau, New Mexico

Science.gov (United States)

Layton, M. E.; Speed, C.; Shukla, M.; Vila, A.; Chon, E.; Kitamikado, C.; Feucht, D. W.; Bedrosian, P.; Pellerin, L.

2016-12-01

Magnetotelluric (MT) and transient electromagnetic (TEM) data were acquired by students from the Summer of Applied Geophysical Experience (SAGE) to construct structural models in and around the Caja del Rio Plateau, New Mexico. The Caja del Rio is located on the La Bajada-Jemez constriction that separates the Española and Santa Domingo basins in the Rio Grande Rift. The Rio Grande Rift, the result of tectonic extensional forces, extends approximately north-south across northern New Mexico. MT data collected in 2016 were merged with that from previous years to make up an 11 km north line and a 16 km south line extending from the west side of the Caja Del Rio to the east off the plateau in the Old Buckman Road area. The resistivity distributions revealed in one-dimensional (1-D) and two-dimensional (2-D) inverse models show some robust features. Models of the north are interpreted as a top resistive layer (convention) point in the northwest direction towards the conductive Valles Caldera. The MT models are consistent with geologic interpretations of the stratigraphic units. In addition, models disclose an additional conductive layer below the basement that we interpret as the mid-crustal conductor. Transient electromagnetic (TEM) data were collected in seven locations atop the Caja del Rio plateau in an attempt to identify the basal contact of the Cerros del Rio volcanic field, which, in turn, allow for the thickness of these basaltic and andesitic deposits to be mapped across the plateau. One-dimensional inverse models produced from the TEM data were aligned and interpreted geologically. A resistive ( 1000 ohm-m) unit, interpreted to represent the Cerros del Rio volcanics, thickens from 70m to 175m from southeast to northwest. The volcanics are overlain by a thin conductor, interpreted as weathered material. The resistive body is underlain by a thicker conductor, interpreted as sedimentary rocks of the Tertiary-aged Santa Fe Group.

Soil erosion assessment in the core area of the Loss Plateau

Science.gov (United States)

Yang, Bo; Wang, Quanjiu

2017-11-01

In order to explore the spatiotemporal evolution of erosion and sediment yield before and after Grain for Green Project in the Loss Plateau. The soil loss of Yulin is estimated by Chinese Water Erosion on Hill Slope Prediction Model. The result shows that the spatiotemporal variations of soil erosion are largely related to rainfall erosion distribution, slope, and land use type. The overall soil erosion categories in the south region are higher than that of the northwest. Mid slopes and valleys are the major topographical contributors to soil erosion. With the growth of slope gradient, soil erosion significantly increased. The soil loss has a decreasing tendency after Grain for Green Project. The results indicate that the vegetation restoration as part of the Grain for Green Project on the Loess Plateau is effective.

Atmospheric deposition of trace elements recorded in snow from the Mt. Nyainqêntanglha region, southern Tibetan Plateau.

Science.gov (United States)

Huang, Jie; Kang, Shichang; Zhang, Qianggong; Guo, Junming; Chen, Pengfei; Zhang, Guoshuai; Tripathee, Lekhendra

2013-08-01

In May 2009, snowpit samples were collected from a high-elevation glacier in the Mt. Nyainqêntanglha region on the southern Tibetan Plateau. A set of elements (Al, V, Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg and Pb) was analyzed to investigate the concentrations, deposition fluxes of trace elements, and the relative contributions from anthropogenic and natural sources deposited on the southern Tibetan Plateau. Concentrations of most of the trace elements in snowpit samples from the Zhadang glacier are significantly lower than those examined from central Asia (e.g., eastern Tien Shan), with higher concentrations during the non-monsoon season than during the monsoon season. The elements of Al, V, Cr, Mn, Co, and Ni display low crustal enrichment factors (EFs), while Cu, Zn, Cd, Hg, and Pb show high EF values in the snow samples, suggesting anthropogenic inputs are potentially important for these elements in the remote, high-elevation atmosphere on the southern Tibetan Plateau. Together with the fact that the concentration levels of such elements in the Mt. Nyainqêntanglha region are significantly higher than those observed on the south edge of the Tibetan Plateau, our results suggest that the high-elevation atmosphere on the southern Tibetan Plateau may be more sensitive to variations in the anthropogenic emissions of atmospheric trace elements than that in the central Himalayas. Moreover, the major difference between deposition fluxes estimated in our snow samples and those recently measured at Nam Co Station for elements such as Cr and Cu may suggest that atmospheric deposition of some of trace elements reconstructed from snowpits and ice cores could be grossly underestimated on the Tibetan Plateau. Copyright © 2013 Elsevier Ltd. All rights reserved.

Prevalence of plateau iris configuration in primary angle closure glaucoma using ultrasound biomicroscopy in the Indian population

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Gaurav Kumar

2012-01-01

Full Text Available Purpose: To report the prevalence of plateau iris in patients with primary angle closure glaucoma (PACG, in North India. Materials and Methods: The patients with PACG, attending the glaucoma services at a tertiary care center in North India were included in the study. All patients had undergone Nd-YAG laser peripheral iridotomy at least four weeks prior to inclusion in the study. Four weeks prior to inclusion in the study, none of the patients had used pilocarpine. Ultrasound Biomicroscopy (UBM images were qualitatively evaluated and plateau iris configuration was defined in an eye if the following criteria were fulfilled in two or more quadrants: anteriorly directed ciliary process supporting the peripheral iris, steep rise of iris root from its point of insertion followed by a downward angulation from the corneoscleral wall, absent ciliary sulcus, and iridotrabecular contact in the same quadrant. Results: One hundred and one eyes were included in the study. There were 63 (62.4% females and 38 (37.6% males. The mean age of the patients was 57.8 ± 9.5 years (range: 42 to 78 years. The mean axial length in the study population was 22.2 ± 1.1 mm. The mean spherical equivalent refraction was 0.06 ± 1.12 D. The mean intraocular pressure was 18.5 ± 4.7 mmHg (range: 12 - 24 mmHg. Twenty-nine (28.7% subjects were diagnosed with plateau iris on the basis of above-defined criteria. Of the 29 eyes, 18 (62.1% subjects had plateau iris in two quadrants, nine (31.03% in three quadrants, and two (6.8% had this configuration in all the four quadrants. Conclusions: Approximately 30% of the eyes with PACG had plateau iris on UBM. Plateau iris was very often the cause for residual angle closure following laser peripheral iridotomy in Indian eyes with PACG.

Provenance of cryoconite deposited on the glaciers of the Tibetan Plateau: new insights from Nd-Sr isotopic composition and size distribution

Science.gov (United States)

Dong, Z.

2016-12-01

This study presents the Nd-Sr isotopic compositions and size distributions of cryoconite deposited on the glaciers at different locations on the Tibetan Plateau, in order to trace its source areas and the provenance of long-range transported (LRT) Asian dust on the Tibetan Plateau. The result of SEM-EDS analysis indicated that mineral dust particles were dominant in the cryoconite. Most of the cryoconite samples from the Tibetan Plateau indicated different Sr and Nd isotopic composition compared with sand from large deserts (e.g., the Taklimakan and Qaidam deserts). Some cryoconite samples showed very similar Nd-Sr isotopic ratios compared with those of nearby glacier basins (e.g., at Laohugou Glacier No.12, Dongkemadi Glacier and Shiyi Glacier), indicating the potential input of local crustal dust to cryoconite. The volume-size distribution for the cryoconite particles also indicated bi-modal distribution graphs with volume median diameters ranging from 0.57 to 20 μm and from 20 to 100 μm, demonstrating the contribution of both LRT Asian dust and local dust inputs to cryoconite. Based on the particle size distribution, we calculated a mean number ratio of local dust contribution to cryoconite ranging from 0.7% (Baishui Glacier No.1) to 17.6% (Shiyi Glacier) on the Tibetan Plateau. In general, the marked difference in the Nd-Sr isotopic ratios of cryoconite compared with those of large deserts probably indicates that, materials from the western deserts have not been easily transported to the hinterland of Tibetan Plateau by the Westerlies under the current climatic conditions, and the arid deserts on the Tibetan Plateau are the most likely sources for cryoconite deposition. The resistance of the Tibetan Plateau to the Westerlies may have caused such phenomena, especially for LRT eolian dust transported over the Tibetan Plateau. Thus, this work is of great importance in understanding the large scale eolian dust transport and climate over the Tibetan Plateau.

IOD influence on the early winter tibetan plateau snow cover: diagnostic analyses and an AGCM simulation

Energy Technology Data Exchange (ETDEWEB)

Yuan, Chaoxia; Tozuka, Tomoki; Yamagata, Toshio [The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, Tokyo (Japan)

2012-10-15

Using diagnostic analyses and an AGCM simulation, the detailed mechanism of Indian Ocean Dipole (IOD) influence on the early winter Tibetan Plateau snow cover (EWTPSC) is clarified. In early winter of pure positive IOD years with no co-occurrence of El Nino, the anomalous dipole diabatic heating over the tropical Indian Ocean excites the baroclinic response in the tropics. Since both baroclinic and barotropic components of the basic zonal wind over the Arabian Peninsula increase dramatically in early winter due to the equatorward retreat of the westerly jet, the baroclinic mode excites the barotropic Rossby wave that propagates northeastward and induces a barotropic cyclonic anomaly north of India. This enables the moisture transport cyclonically from the northern Indian Ocean toward the Tibetan Plateau. The convergence of moisture over the plateau explains the positive influence of IOD on the EWTPSC. In contrast, the basic zonal wind over the Arabian Peninsula is weak in autumn. This is not favorable for excitation of the barotropic Rossby wave and teleconnection, even though the IOD-related diabatic heating anomaly in autumn similar to that in early winter exists. This result explains the insignificant (significant positive) partial correlation between IOD and the autumn (early winter) Tibetan Plateau snow cover after excluding the influence of ENSO. The sensitivity experiment forced by the IOD-related SST anomaly within the tropical Indian Ocean well reproduces the baroclinic response in the tropics, the teleconnection from the Arabian Peninsula, and the increased moisture supply to the Tibetan Plateau. Also, the seasonality of the atmospheric response to the IOD is simulated. (orig.)

Influences of climate change on area variation of Qinghai Lake on Qinghai-Tibetan Plateau since 1980s.

Science.gov (United States)

Tang, Lingyi; Duan, Xiaofang; Kong, Fanjin; Zhang, Fan; Zheng, Yangfan; Li, Zhen; Mei, Yi; Zhao, Yanwen; Hu, Shuijin

2018-05-09

Qinghai-Tibetan Plateau is the most sensitive region to global warming on Earth. Qinghai Lake, the largest lake on the plateau, has experienced evident area variation during the past several decades. To quantify the area changes of Qinghai Lake, a satellite-based survey based on Landsat images from the 1980s to 2010s has been performed. In addition, meteorological data from all the seven available stations on Qinghai-Tibetan Plateau has been analyzed. Area of Qinghai Lake shrank ~2% during 1987-2005, and then increased ~3% from 2005-2016. Meanwhile, the average annual temperature increased 0.319 °C/10 y in the past 50 years, where the value is 0.415 °C/10 y from 2005-2016. The structural equation modeling (SEM) shows that precipitation is the primary factor influencing the area of Qinghai Lake. Moreover, temperature might be tightly correlated with precipitation, snow line, and evaporation, thereby indirectly causes alternations of the lake area. This study elucidated the significant area variation of water body on the Qinghai-Tibetan Plateau under global warming since 1980s.

Deep Vadose Zone Characterization at the Hanford Site: Accomplishments from the Last Ten Years

International Nuclear Information System (INIS)

Brown, Christopher F.; Serne, R. Jeffrey

2008-01-01

The overall goal of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., is to define risks from past and future single-shell tank farm activities at Hanford. To meet this goal, CH2M HILL Hanford Group, Inc. tasked scientists from Pacific Northwest National Laboratory (PNNL) to perform detailed analyses on vadose zone sediments collected within/adjacent to the twelve single-shell tank farms contained within Hanford's Central Plateau region. This work has been performed under the Resource Conservation and Recovery Act (RCRA) Corrective Action Program and is associated with the Hanford Federal Facility Agreement and Consent Order. While there are many facets to the laboratory studies employed by PNNL, the four primary objectives of this work are to: identify the type and quantity of contamination present, understand the physical processes that affect the transport of contaminants in the vadose zone sediments, when practical, identify the source(s) of the contamination found in the sediment samples, and when practical, determine if a link can be made between the vadose zone contamination observed and any known groundwater contaminants in the vicinity. Since its inception in 1997, PNNL's Vadose Zone Characterization Project has evolved to better meet these four key objectives. The single-largest adaptation of the Vadose Zone Characterization Project over its ten years of operation was the advent of a tiered sample analysis approach. Use of a tiered approach allows resources to be focused on those samples/tests that provide the largest amount of scientific information to best meet the four key project objectives within the budget available. Another significant, but more recent, adaptation has been the implementation of a rapid turnaround characterization process in which sediment samples are analyzed in near real-time to aid drilling activities within the tank farms. This paper highlights details of the characterization activities performed as well

Uranium exploration of the Colorado Plateau: interim staff report

International Nuclear Information System (INIS)

1980-10-01

This report is an issue of the original draft copy of the Interim Staff Report on Uranium Exploration on the Colorado Plateau, dated June 1951. The original draft copy was only recently located and is being published at this time because of the interest in the contained historical content. The table of contents of this report lists: history of uranium mining; geology; proposed program for the geologic investigations section; general activities of industry and government; and future exploration of sedimentary uranium deposits and anticipated results. Under the proposed program section are: future of the copper-uranium deposits as a source of uranium; uraniferous asphaltite deposits; and commission exploration and future possibilities. The section on general activities of industry and government includes: exploratory and development drilling; field investigations and mapping; early geologic investigations and investigations by the US geological survey; and geophysical exploration. Tables are also presented on: uranium production by districts; US Geological survey drilling statistics; Colorado Exploration Branch drilling statistics; summary of drilling projects; and comparative yearly core-drill statistics on the Colorado Plateau

Modeling and Mapping Soil Moisture of Plateau Pasture Using RADARSAT-2 Imagery

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Xun Chai

2015-01-01

Full Text Available Accurate soil moisture retrieval of a large area in high resolution is significant for plateau pasture. The object of this paper is to investigate the estimation of volumetric soil moisture in vegetated areas of plateau pasture using fully polarimetric C-band RADARSAT-2 SAR (Synthetic Aperture Radar images. Based on the water cloud model, Chen model, and Dubois model, we proposed two developed algorithms for soil moisture retrieval and validated their performance using experimental data. We eliminated the effect of vegetation cover by using the water cloud model and minimized the effect of soil surface roughness by solving the Dubois equations. Two experimental campaigns were conducted in the Qinghai Lake watershed, northeastern Tibetan Plateau in September 2012 and May 2013, respectively, with simultaneous satellite overpass. Compared with the developed Chen model, the predicted soil moisture given by the developed Dubois model agreed better with field measurements in terms of accuracy and stability. The RMSE, R2, and RPD value of the developed Dubois model were (5.4, 0.8, 1.6 and (3.05, 0.78, 1.74 for the two experiments, respectively. Validation results indicated that the developed Dubois model, needing a minimum of prior information, satisfied the requirement for soil moisture inversion in the study region.

Spatiotemporal drought variability of the eastern Tibetan Plateau during the last millennium

Science.gov (United States)

Deng, Yang; Gou, Xiaohua; Gao, Linlin; Yang, Meixue; Zhang, Fen

2017-09-01

Tibetan Plateau is the headwater region of many major Asian rivers and very susceptive to climate change. Therefore, knowledge about climate and its spatiotemporal variability in this area is very important for ecological conservation, water resource management and social development. The aim of this study was to reconstruct and analyze the hydroclimate variation on eastern Tibetan Plateau (ETP) over many centuries and explore possible forcing factors on regional hydroclimate variability. We used 118 tree-ring chronologies from ETP to reconstruct the gridded May-July Standardized Precipitation Evapotranspiration Index for the ETP over the last millennium. The reconstruction was developed using an ensemble point-by-point reconstruction method, and a searching region method was used to locate the candidate tree-ring chronologies. The reconstructions have nicely captured the spatial and temporal features of the regional drought variation. The drought variations in south and north of 32.5°N are notably different, which may be related to the divergence influence of North Atlantic Oscillation on the climate systems in the south and north, as well as differences in local climate. Spectral analysis and series comparison suggest that the drought variation in the northeastern Tibetan Plateau has been possibly influenced by solar activity on centurial and longer time scale.

The modulation of Tibetan Plateau heating on the multi-scale northernmost margin activity of East Asia summer monsoon in northern China

Science.gov (United States)

Zhang, Jie; Liu, Chen; Chen, Haishan

2018-02-01

The northernmost margin of East Asian summer monsoon (EASM) could well reflect wet/dry climate variability in the EASM marginal zone (northern China). The study shows that EASM occurs in northern China from Meiyu period to midsummer, and it is also the advancing period of the northern margin of EASM (NMEASM) before the 43rd pentad. NMEASM activity exhibits multi-scale variability, at cycles of 2-3-yr, 4-6-yr and 9-12-yr, which respond not only to EASM intensity but also to westerly circulation anomaly, exhibiting the mid-latitude Eurasian waves and the high-latitude Eurasian teleconnection (EU) patterns. The positive anomalies of Silk Road pattern and EU pattern in recent two decades contribute to the enhanced west-ridge and east-trough anomaly around 120°E over northern China, leading to divergence of moisture flux and north wind anomaly, which is helpful for southward western pacific subtropical high (WPSH) and southward NMEASM. Negative Eurasian pattern along subtropical Jet leads to anticyclone anomaly over south of the Yangtze River, deep trough and north wind anomaly along the west coast of the subtropical Pacific, contributing to southward WPSH and NMEASM at the cycle of 4-6-yr. Remote forcing sources of these anomalous Eurasian waves include North Europe, north of Caspian Sea, Central Asia, Tibetan Plateau and the west of Lake Baikal; the south of Lake Baikal is a local forcing region. The Tibetan Plateau heating and snow cover could modulate Eurasian wave pattern at multi-scale, which could be used as prediction reference of multi-scale NMEASM.

Climatic changes on orbital and sub-orbital time scale recorded by the Guliya ice core in Tibetan Plateau

Institute of Scientific and Technical Information of China (English)

姚檀栋; 徐柏青; 蒲健辰

2001-01-01

Based on ice core records in the Tibetan Plateau and Greenland, the features and possible causes of climatic changes on orbital and sub-orbital time scale were discussed. Orbital time scale climatic change recorded in ice core from the Tibetan Plateau is typically ahead of that from polar regions, which indicates that climatic change in the Tibetan Plateau might be earlier than polar regions. The solar radiation change is a major factor that dominates the climatic change on orbital time scale. However, climatic events on sub-orbital time scale occurred later in the Tibetan Plateau than in the Arctic Region, indicating a different mechanism. For example, the Younger Dryas and Heinrich events took place earlier in Greenland ice core record than in Guliya ice core record. It is reasonable to propose the hypothesis that these climatic events were affected possibly by the Laurentide Ice Sheet. Therefore, ice sheet is critically important to climatic change on sub-orbital time scale in some ice ages.

Greenland plateau jets

Directory of Open Access Journals (Sweden)

George William Kent Moore

2013-08-01

Full Text Available The high ice-covered topography of Greenland represents a significant barrier to atmospheric flow and, as a direct and indirect result, it plays a crucial role in the coupled climate system. The wind field over Greenland is important in diagnosing regional weather and climate, thereby providing information on the mass balance of the ice sheet as well as assisting in the interpretation of ice core data. Here, we identify a number of hitherto unrecognised features of the three-dimensional wind field over Greenland; including a 2500-km-long jet along the central ice sheet's western margin that extends from the surface into the middle-troposphere, as well as a similar but smaller scale and less intense feature along its eastern margin. We refer to these features as Greenland Plateau Jets. The jets are coupled to the downslope katabatic flow and we argue that they are maintained by the zonal temperature gradients associated with the strong temperature inversion over the central ice sheet. Their importance for Greenland's regional climate is discussed.

Eocene to Miocene Out-of-Sequence Deformation in the Eastern Tibetan Plateau: Insights From Shortening Structures in the Sichuan Basin

Science.gov (United States)

Tian, Yuntao; Kohn, Barry P.; Qiu, Nansheng; Yuan, Yusong; Hu, Shengbiao; Gleadow, Andrew J. W.; Zhang, Peizhen

2018-02-01

A distinctive NNE trending belt of shortening structures dominates the topography and deformation of the eastern Sichuan Basin, 300 km east of the Tibetan Plateau. Debate continues as to whether the structures resulted from Cenozoic eastward growth of the Tibetan Plateau. A low-temperature thermochronology (AFT and AHe) data set from four deep boreholes and adjacent outcrops intersecting a branch of the shortening structures indicates distinctive differential cooling at 35-28 Ma across the structure, where stratigraphy has been offset vertically by 0.8-1.3 km. This result forms the first quantitative evidence for the existence of a late Eocene-Oligocene phase of shortening in the eastern Sichuan Basin, synchronous with the early phase of eastward growth and extrusion of the Tibetan Plateau. Further, a compilation of regional Cenozoic structures reveals a Miocene retreat of deformation from the foreland basin to the hinterland areas. Such a tectonic reorganization indicates that Eocene to Miocene deformation in the eastern Tibetan Plateau is out-of-sequence and was probably triggered by enhanced erosion in the eastern Tibetan Plateau.

Deep Vadose Zone Treatability Test for the Hanford Central Plateau. Interim Post-Desiccation Monitoring Results, Fiscal Year 2015

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tartakovsky, Guzel D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chronister, Glen B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-09-01

A field test of desiccation is being conducted as an element of the Deep Vadose Zone Treatability Test Program. The active desiccation portion of the test has been completed. Monitoring data have been collected at the field test site during the post-desiccation period and are reported herein. This is an interim data summary report that includes about 4 years of post-desiccation monitoring data. The DOE field test plan proscribes a total of 5 years of post-desiccation monitoring.

Topographic and sedimentary features in the Yap subduction zone and their implications for the Caroline Ridge subduction

Science.gov (United States)

Dong, Dongdong; Zhang, Zhengyi; Bai, Yongliang; Fan, Jianke; Zhang, Guangxu

2018-01-01

The Yap subduction zone in the western Pacific presents some unique features compared to normal intra-oceanic subduction zones such as the subduction of an oceanic plateau. However, due to the relative paucity of geophysical data, the detailed structure remains unknown in this area. In this study, we present the latest high-quality swath bathymetry and multi-channel seismic data acquired synchronously in 2015 across the Yap subduction zone. The topographic and sedimentary features are intensively investigated and a modified evolutionary model of the Yap subduction zone is proposed. The two-stage evolution of the Parece Vela Basin (PVB) produced fabrics that are N-S trending and NW-SE trending. Our seismic data clearly reveal landslide deposits at the upper slope break of the forearc, to the north of the Yap Island, which was identified as the fault notch denoting a lithological boundary in previous work. The swath bathymetry and seismic profile reveal detailed horst and graben structures, including a crescent-shaped fault zone near the contact between the Yap Trench and the Caroline Ridge. A simple geometric model is proposed to explain the structure formation, indicating that the higher topography of the Caroline Ridge resulted in enhanced bending-related extension. A seismic angular unconformity (named R1) is identified in the Sorol Trough, marking the onset of rifting in the trough. Based on the sequence thickness and deposition rate by Deep Sea Drilling Project (DSDP), it is deduced that the Sorol Trough formed at 10 Ma or even earlier. A modified model for the Yap subduction zone evolution is proposed, incorporating three major tectonic events: the proto-Yap Arc rupture in the Oligocene, the collision of the Caroline Ridge and the Yap Trench in the late Oligocene or middle Miocene, and the onset of the Sorol Trough rifting in the late Miocene.

Climate change and its impacts on vegetation distribution and net primary productivity of the alpine ecosystem in the Qinghai-Tibetan Plateau.

Science.gov (United States)

Gao, Qingzhu; Guo, Yaqi; Xu, Hongmei; Ganjurjav, Hasbagen; Li, Yue; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Liu, Shuo

2016-06-01

Changes in climate have caused impacts on ecosystems on all continents scale, and climate change is also projected to be a stressor on most ecosystems even at the rate of low- to medium-range warming scenarios. Alpine ecosystem in the Qinghai-Tibetan Plateau is vulnerable to climate change. To quantify the climate change impacts on alpine ecosystems, we simulated the vegetation distribution and net primary production in the Qinghai-Tibetan Plateau for three future periods (2020s, 2050s and 2080s) using climate projection for RCPs (Representative Concentration Pathways) RCP4.5 and RCP8.5 scenarios. The modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ model) was parameter and test to make it applicable to the Qinghai-Tibetan Plateau. Climate projections that were applied to LPJ model in the Qinghai-Tibetan Plateau showed trends toward warmer and wetter conditions. Results based on climate projections indicated changes from 1.3°C to 4.2°C in annual temperature and changes from 2% to 5% in annual precipitation. The main impacts on vegetation distribution was increase in the area of forests and shrubs, decrease in alpine meadows which mainly replaced by shrubs which dominated the eastern plateau, and expanding in alpine steppes to the northwest dominated the western and northern plateau. The NPP was projected to increase by 79% and 134% under the RCP4.5 and RCP8.5. The projected NPP generally increased about 200gC·m(-2)·yr(-1) in most parts of the plateau with a gradual increase from the eastern to the western region of the Qinghai-Tibetan Plateau at the end of this century. Copyright © 2016 Elsevier B.V. All rights reserved.

Quartz OSL Dating of the loess deposit in the eastern Tibetan Plateau and its environment implications since the Last Glaciation

Science.gov (United States)

Yang, S.; Cheng, T.; Liu, W.; Fang, X.

2017-12-01

Loess deposit is widespread in the Chuanxi Plateau, the eastern Tibetan Plateau, which is a critical archive for understanding the aeolian process, the evolution of the westerly and the environment changes on the Plateau. Previous studies have shown its aeolian origin, and mainly transported by wind from the western part of the Tibetan Plateau. However, the aeolian processes of the loess and its environment implications are not well understood mainly due to lack of detailed age controls. We carry out a combined quartz optically stimulated luminescence (OSL) dating and accelerator mass spectrometry radiocarbon dating (AMS 14-C) for the loess deposits in Garzê and Jinchuan. The results indicate that the quartz OSL dating can provide reliable age controls for the loess-paleosol sequences from the Chuanxi Plateau, showing the potential of OSL to date loess in the high altitude region. The results indicate that the OSL ages are in agreement with the observed stratigraphy in the field. The constructed OSL and AMS 14-C chronology of the Garzê loess reveals that the widespread loess in Ganzi Region deposited since the Last Glacial. The dust accumulation is rapid during marine isotope stage (MIS) 3 and 2, and a relative low accumulation rate in the Holocene, which may related with the desertification processes of the inner Tibetan Plateau.

Rainfall Erosivity Factor for Uasin Gishu Plateau, Kenya | Kariaga ...

African Journals Online (AJOL)

Runoff plots were established on bare soil classified as Dystric Nitosols (Typic Rhodudults) at Moi University Main Campus, on Uasin Gishu Plateau, Kenya. The objective of the study was to determine the best erosivity factor for the area. This was found to be EI30, defined as the product of the rainstorm's kinetic energy and ...

Potential impacts to perennial springs from tar sand mining, processing, and disposal on the Tavaputs Plateau, Utah, USA

International Nuclear Information System (INIS)

Johnson, William P.; Frederick, Logan E.; Millington, Mallory R.; Vala, David; Reese, Barbara K.; Freedman, Dina R.; Stenten, Christina J.; Trauscht, Jacob S.; Tingey, Christopher E.; Kip Solomon, D.; Fernandez, Diego P.; Bowen, Gabriel J.

2015-01-01

Similar to fracking, the development of tar sand mining in the U.S. has moved faster than understanding of potential water quality impacts. Potential water quality impacts of tar sand mining, processing, and disposal to springs in canyons incised approximately 200 m into the Tavaputs Plateau, at the Uinta Basin southern rim, Utah, USA, were evaluated by hydrogeochemical sampling to determine potential sources of recharge, and chemical thermodynamic estimations to determine potential changes in transfer of bitumen compounds to water. Because the ridgetops in an area of the Tavaputs Plateau named PR Spring are starting to be developed for their tar sand resource, there is concern for potential hydrologic connection between these ridgetops and perennial springs in adjacent canyons on which depend ranching families, livestock, wildlife and recreationalists. Samples were collected from perennial springs to examine possible progression with elevation of parameters such as temperature, specific conductance, pH, dissolved oxygen, isotopic tracers of phase change, water-rock interaction, and age since recharge. The groundwater age dates indicate that the springs are recharged locally. The progression of hydrogeochemical parameters with elevation, in combination with the relatively short groundwater residence times, indicate that the recharge zone for these springs includes the surrounding ridges, and thereby suggests a hydrologic connection between the mining, processing, disposal area and the springs. Estimations based on chemical thermodynamic approaches indicate that bitumen compounds will have greatly enhanced solubility in water that comes into contact with the residual bitumen–solvent mixture in disposed tailings relative to water that currently comes into contact with natural tar. - Highlights: • The potential water quality impacts of the first US tar sand development are considered. • Analyses of perennial springs in adjacent canyons indicate hydrologic

Potential impacts to perennial springs from tar sand mining, processing, and disposal on the Tavaputs Plateau, Utah, USA

Energy Technology Data Exchange (ETDEWEB)

Johnson, William P.; Frederick, Logan E.; Millington, Mallory R. [University of Utah, Department of Geology & Geophysics, Salt lake City, UT 84112 (United States); Vala, David [Murray High School, Murray, UT 84107 (United States); Reese, Barbara K. [Butler Middle School, Cottonwood Heights, UT 84121 (United States); Freedman, Dina R. [Hillside Middle School, Salt Lake City, UT 84108 (United States); Stenten, Christina J. [Draper Park Middle School, Draper, UT 84020 (United States); Trauscht, Jacob S.; Tingey, Christopher E.; Kip Solomon, D.; Fernandez, Diego P.; Bowen, Gabriel J. [University of Utah, Department of Geology & Geophysics, Salt lake City, UT 84112 (United States)

2015-11-01

Similar to fracking, the development of tar sand mining in the U.S. has moved faster than understanding of potential water quality impacts. Potential water quality impacts of tar sand mining, processing, and disposal to springs in canyons incised approximately 200 m into the Tavaputs Plateau, at the Uinta Basin southern rim, Utah, USA, were evaluated by hydrogeochemical sampling to determine potential sources of recharge, and chemical thermodynamic estimations to determine potential changes in transfer of bitumen compounds to water. Because the ridgetops in an area of the Tavaputs Plateau named PR Spring are starting to be developed for their tar sand resource, there is concern for potential hydrologic connection between these ridgetops and perennial springs in adjacent canyons on which depend ranching families, livestock, wildlife and recreationalists. Samples were collected from perennial springs to examine possible progression with elevation of parameters such as temperature, specific conductance, pH, dissolved oxygen, isotopic tracers of phase change, water-rock interaction, and age since recharge. The groundwater age dates indicate that the springs are recharged locally. The progression of hydrogeochemical parameters with elevation, in combination with the relatively short groundwater residence times, indicate that the recharge zone for these springs includes the surrounding ridges, and thereby suggests a hydrologic connection between the mining, processing, disposal area and the springs. Estimations based on chemical thermodynamic approaches indicate that bitumen compounds will have greatly enhanced solubility in water that comes into contact with the residual bitumen–solvent mixture in disposed tailings relative to water that currently comes into contact with natural tar. - Highlights: • The potential water quality impacts of the first US tar sand development are considered. • Analyses of perennial springs in adjacent canyons indicate hydrologic

The Climate Effect of the Topographies at the Northern Margin of the Tibetan Plateau

Science.gov (United States)

Sha, Y.; Shi, Z.; Liu, X.

2017-12-01

The Tibetan Plateau play a crucial role in the formation and evolution of the Asian monsoon-interior aridity climate system. However, the climate effect of other relatively smaller topographies receives less attention. Based on high-resolved general circulation models, we conducted a series of sensitive experiments as with/without mountains, which include the Mongolian Plateau and the Tian Shan Mountains. The numerical simulations reveal the important impacts of the mountain ranges at the northern margins of the Tibetan Plateau. Compared to the main body of the Tibetan Plateau, the uplift of the Mongolian Plateau is essential for the establishment of the strong Siberian High. The East Asian winter monsoon and the westerly jet over the North Pacific Ocean are also significantly strengthened. At present, the Tian Shan Mountains geographically separate the arid interior Asia to the west and east sub-regions. However, the arid west sub-region (Central Asia) and the east sub-region (arid northwestern China) was connected as one large arid region before the uplift of the Tian Shan Mountains. The large arid interior land shares the same precipitation seasonality, with most rains fall in spring and winter while lowest precipitation in summer. After the uplift of the Tian Shan, the large arid region is divided into the west and east sub-regions by the wetter uplifted mountain ranges. More importantly, the precipitation seasonality in the east of the Tian Shan is reversed to be the summer-peak type, which is opposite to that in the Central Asia. The precipitation alteration corresponds well with the change of vertical motion. By the conservation of potential vorticity, the atmosphere stationary waves are modulated. Thus, the remote East Asian monsoon is also modulated. Though enhanced southerly wind blows over East Asia, the monsoon precipitation over the east coast of China and subtropical western Pacific Ocean is significantly reduced as an anticyclonic circulation appears

Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

Directory of Open Access Journals (Sweden)

M. Kopacz

2011-03-01

Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5–15 W m⁻² within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

Groundwater recharge mechanism in an integrated tableland of the Loess Plateau, northern China: insights from environmental tracers

Science.gov (United States)

Huang, Tianming; Pang, Zhonghe; Liu, Jilai; Ma, Jinzhu; Gates, John

2017-11-01

Assessing groundwater recharge characteristics (recharge rate, history, mechanisms (piston and preferential flow)) and groundwater age in arid and semi-arid environments remains a difficult but important research frontier. Such assessments are particularly important when the unsaturated zone (UZ) is thick and the recharge rate is limited. This study combined evaluations of the thick UZ with those of the saturated zone and used multiple tracers, such as Cl, NO3, Br, 2H, 18O, 13C, 3H and 14C, to study groundwater recharge characteristics in an integrated loess tableland in the Loess Plateau, China, where precipitation infiltration is the only recharge source for shallow groundwater. The results indicate that diffuse recharge beneath crops, as the main land use of the study area, is 55-71 mm yr-1 based on the chloride mass balance of soil profiles. The length of time required for annual precipitation to reach the water table is 160-400 yrs. The groundwater is all pre-modern water and paleowater, with corrected 14C age ranging from 136 to 23,412 yrs. Most of the water that eventually becomes recharge originally infiltrated in July-September. The Cl and NO3 contents in the upper UZ are considerably higher than those in the deep UZ and shallow groundwater because of recent human activities. The shallow groundwater has not been in hydraulic equilibrium with present near-surface boundary conditions. The homogeneous material of the UZ and relatively old groundwater age imply that piston flow is the dominant recharge mechanism for the shallow groundwater in the tableland.

Plateau inflation in SUGRA-MSSM

Directory of Open Access Journals (Sweden)

Girish Kumar Chakravarty

2016-09-01

Full Text Available We explored a Higgs inflationary scenario in the SUGRA embedding of the MSSM in Einstein frame where the inflaton is contained in the SU(2 Higgs doublet. We include all higher order non-renormalizable terms to the MSSM superpotential and an appropriate Kähler potential which can provide slow-roll inflaton potential in the D-flat direction. In this model, a plateau-like inflation potential can be obtained if the imaginary part of the neutral Higgs acts as the inflaton. The inflationary predictions of this model are consistent with the latest CMB observations. The model represents a successful Higgs inflation scenario in the context of Supergravity and it is compatible with Minimal Supersymmetric extension of the Standard Model.

Hf-Nd isotope constraints on the origin of the Cretaceous Caribbean plateau and its relationship to the Galápagos plume

Science.gov (United States)

Thompson, P. M. E.; Kempton, P. D.; White, R. V.; Kerr, A. C.; Tarney, J.; Saunders, A. D.; Fitton, J. G.; McBirney, A.

2004-01-01

Formation of the Cretaceous Caribbean plateau, including the komatiites of Gorgona, has been linked to the currently active Galápagos hotspot. We use Hf-Nd isotopes and trace element data to characterise both the Caribbean plateau and the Galápagos hotspot, and to investigate the relationship between them. Four geochemical components are identified in the Galápagos mantle plume: two 'enriched' components with ɛHf and ɛNd similar to enriched components observed in other mantle plumes, one moderately enriched component with high Nb/Y, and a fourth component which most likely represents depleted MORB source mantle. The Caribbean plateau basalt data form a linear array in Hf-Nd isotope space, consistent with mixing between two mantle components. Combined Hf-Nd-Pb-Sr-He isotope and trace element data from this study and the literature suggest that the more enriched Caribbean end member corresponds to one or both of the enriched components identified on Galápagos. Likewise, the depleted end member of the array is geochemically indistinguishable from MORB and corresponds to the depleted component of the Galápagos system. Enriched basalts from Gorgona partially overlap with the Caribbean plateau array in ɛHf vs. ɛNd, whereas depleted basalts, picrites and komatiites from Gorgona have a high ɛHf for a given ɛNd, defining a high- ɛHf depleted end member that is not observed elsewhere within the Caribbean plateau sequences. This component is similar, however, in terms of Hf-Nd-Pb-He isotopes and trace elements to the depleted plume component recognised in basalts from Iceland and along the Reykjanes Ridge. We suggest that the Caribbean plateau represents the initial outpourings of the ancestral Galápagos plume. Absence of a moderately enriched, high Nb/Y component in the older Caribbean plateau (but found today on the island of Floreana) is either due to changing source compositions of the plume over its 90 Ma history, or is an artifact of limited sampling. The

Paleodrainage of the Columbia River system on the Columbia Plateau of Washington State: a summary

International Nuclear Information System (INIS)

Fecht, K.R.; Reidel, S.P.; Tallman, A.M.

1985-12-01

The evolution of the Columbia River drainage system on the Columbia Plateau of Washington in the last 17 My reflects the geologic history of the plateau. We have updated an interpretation of the evolution of the Columbia River system and defined the geomorphic and structural features that have controlled the position of ancestral streams. The sequence of geologic events and the resulting drainage system for various time intervals in the last 17 My are summarized below. 121 refs., 14 figs

The long-term trends (1982-2006) in vegetation greenness of the alpine ecosystem in the Qinghai-Tibetan Plateau

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Zhang, Li; Guo, Huadong; Wang, Cuizhen; Ji, Lei; Li, Jing; Wang, Kun; Dai, Lin

2014-01-01

The increased rate of annual temperature in the Qinghai-Tibetan Plateau exceeded all other areas of the same latitude in recent decades. The influence of the warming climate on the alpine ecosystem of the plateau was distinct. An analysis of alpine vegetation under changes in climatic conditions was conducted in this study. This was done through an examination of vegetation greenness and its relationship with climate variability using the Advanced Very High Resolution Radiometer satellite imagery and climate datasets. Vegetation in the plateau experienced a positive trend in greenness, with 18.0 % of the vegetated areas exhibiting significantly positive trends, which were primarily located in the eastern and southwestern parts of the plateau. In grasslands, 25.8 % of meadows and 14.1 % of steppes exhibited significant upward trends. In contrast, the broadleaf forests experienced a trend of degradation. Temperature, particularly summer temperature, was the primary factor promoting the vegetation growth in the plateau. The wetter and warmer climate in the east contributed to the favorable conditions for vegetation. The alpine meadow was mostly sensitive to temperature, while the steppes were sensitive to both temperature and precipitation. Although a warming climate was expected to be beneficial to vegetation growth in the alpine region, the rising temperature coupled with reduced precipitation in the south did not favor vegetation growth due to low humidity and poor soil moisture conditions.

Salinity drives archaeal distribution patterns in high altitude lake sediments on the Tibetan Plateau.

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Liu, Yongqin; Priscu, John C; Xiong, Jinbo; Conrad, Ralf; Vick-Majors, Trista; Chu, Haiyan; Hou, Juzhi

2016-03-01

Archaeal communities and the factors regulating their diversity in high altitude lakes are poorly understood. Here, we provide the first high-throughput sequencing study of Archaea from Tibetan Plateau lake sediments. We analyzed twenty lake sediments from the world's highest and largest plateau and found diverse archaeal assemblages that clustered into groups dominated by methanogenic Euryarchaeota, Crenarchaeota and Halobacteria/mixed euryarchaeal phylotypes. Statistical analysis inferred that salinity was the major driver of community composition, and that archaeal diversity increased with salinity. Sediments with the highest salinities were mostly dominated by Halobacteria. Crenarchaeota dominated at intermediate salinities, and methanogens were present in all lake sediments, albeit most abundant at low salinities. The distribution patterns of the three functional types of methanogens (hydrogenotrophic, acetotrophic and methylotrophic) were also related to changes in salinity. Our results show that salinity is a key factor controlling archaeal community diversity and composition in lake sediments on a spatial scale that spans nearly 2000 km on the Tibetan Plateau. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Phylogeographic investigation and ecological niche modelling of the endemic frog species Nanorana pleskei revealed multiple refugia in the eastern Tibetan Plateau.

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Wang, Bin; Xie, Feng; Li, Jiannan; Wang, Gang; Li, Cheng; Jiang, Jianping

2017-01-01

The largest plateau Tibetan Plateau supplied an excellent opportunity to investigate the influence of the Pleistocene events on the high-elevation species. To test for the alternative hypotheses of Pleistocene glacial refugia, we used partial sequences of two mitochondrial genes and one nuclear gene to examine the phylogeographic patterns of the endemic frog species Nanorana pleskei across its known range in the eastern Tibetan Plateau, and conducted species distribution modelling (SDM) to explore changes of its distribution range through current and paleo periods. In all data sets, the species was divided into lineage north occupying open plateau platform and lineage south colonizing the mountainous plateau. The divergence of two major clades was estimated at the early Pleistocene. In mtDNA, lineage north contained northeastern and northwestern sublineages, and lineage south had two overlapping-distributed sublineages. Different lineages possessed distinct demographic characteristics, i.e., subdivision in the northeastern sublineage, historical bottleneck effects and recent expansions in the northwestern sublineage and the southeastern sublineage. SDMs depicted that stable suitable habitats had existed in the upper-middle streams of the Yellow River, Dadu River, Jinsha River and Yalong River. These regions were also recognized as the ancestral areas of different lineages. In conclusion, Nanorana pleskei lineages have probably experienced long-term separations. Stable suitable habitats existing in upper-middle streams of major rivers on the eastern Tibetan Plateau and distinct demographic dynamics of different lineages indicated that the lineages possessed independent evolutionary processes in multiple glacial refugia. The findings verified the profound effects of Pleistocene climatic fluctuations on the plateau endemic species.

Control of electron localization to isolate and enhance molecular harmonic plateau in asymmetric HeH2+ system

International Nuclear Information System (INIS)

Lu, Ruifeng; Yu, Chao; Wang, Yunhui; Shi, Qi; Zhang, Yadong

2014-01-01

High-order harmonic generation from the asymmetric molecular ion HeH 2+ exposed to intense laser fields was investigated by quantum wave packet calculations in which the initial wave packet of HeH 2+ was prepared in the first excited 2pσ state. The calculated molecular harmonic plateau at low frequencies was effectively isolated and enhanced by adjusting the carrier-envelope phase (CEP) of the laser field. Furthermore, double-well model, time-dependent electronic density, electronic state population, and time-frequency analyses were presented to explain the underlying mechanism of the efficient isolated molecular plateau. By taking advantage of the CEP effect to control the electronic dynamics, this isolated molecular plateau can be used to generate high-intensity single attosecond pulses.

Strontium isotope evidence for a highly mobile population on the Pamir Plateau 2500 years ago

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Wang, Xueye; Tang, Zihua; Wu, Jing; Wu, Xinhua; Wu, Yiqun; Zhou, Xinying

2016-10-01

Archeological researches have proposed arguments for human mobility and long-distance trading over the Eurasia before the Silk Roads. Here we utilize biologically available strontium isotope analysis to assess the extent of pre-Silk Road population movements and cultural communications across the Asian interior. From an early Iron Age cemetery (ca. 2500 yr B.P.) on the eastern Pamir Plateau, mean 87Sr/86Sr ratios from 34 individuals display considerable isotopic variability, and 10 individuals are distinguished as migrants based on the local strontium isotope range of 0.710296-0.710572 defined by 12 ovicaprine bones. Comparison of the proportion (10/34) with the regional census data completed in 1909 A.D. (3% non-locals) suggests a highly migratory behavior on the plateau 2500 years ago. Furthermore, exotic mortuary objects, such as silk fabrics from eastern China and angular harp originated from the Near East, clearly demonstrate an interaction between different cultures on the plateau before the establishment of the Silk Road.

Ecotone shift and major droughts during the mid-late Holocene in the central Tibetan Plateau.

Science.gov (United States)

Shen, Caiming; Liu, Kam-Biu; Morrill, Carrie; Overpeck, Jonathan T; Peng, Jinlan; Tang, Lingyu

2008-04-01

A well-dated pollen record from a large lake located on the meadow-steppe ecotone provides a history of ecotone shift in response to monsoonal climate changes over the last 6000 years in the central Tibetan Plateau. The pollen record indicates that the ecotone shifted eastward during 6000-4900, 4400-3900, and 2800-1600 cal. yr BP when steppes occupied this region, whereas it shifted westward during the other intervals when the steppes were replaced by meadows. The quantitative reconstruction of paleoclimate derived from the pollen record shows that monsoon precipitation fluctuated around the present level over the last 6000 years in the central Tibetan Plateau. Three major drought episodes of 5600-4900, 4400-3900, and 2800-2400 cal. yr BP are detected by pollen signals and lake sediments. Comparison of our record with other climatic proxy data from the Tibetan Plateau and other monsoonal regions shows that these episodes are three major centennial-scale monsoon weakening events.

The involvement of DNA repair genes in the hypoxia-dependent NLCQ-1 (NSC 709257) toxicity and its synergistic interaction with cisplatin or melphalan

International Nuclear Information System (INIS)

Papadopoulou, M.V.; Xue, C.-J.; Bloomer, W.D.

2003-01-01

4-[3-(2-Nitro-1-imidazolyl)-propylamino]-7-chloro-quinoline hydrochloride (NLCQ-1) is a weakly DNA-intercalating hypoxia selective cytotoxin, which synergistically enhances the antitumor effect of several chemotherapeutic agents or radiation against mouse tumors or human xenografts. Synergy with melphalan (L-PAM) or cisplatin (cisPt) requires hypoxic pre-exposure of cells to NLCQ-1 or, in mice, administration of NLCQ-1 about 1 h before L-PAM or cisPt. This suggests that NLCQ-1 may cause DNA lesions upon reductive metabolism. To indirectly identify such lesions, rodent cell lines defective in specific DNA repair genes (EM9 and UV41) and their repair-proficient parental AA8, were exposed to NLCQ-1 alone and in combination with L-PAM or cisPt under hypoxic/aerobic conditions and appropriate routes, and assessed for clonogenicity. Selected comparisons with tirapazamine (TPZ) were also performed. DNA ssbs were identified by using the alkaline comet assay. Synergism was assessed by isobologramic analysis. EM9, which lack the functional XRCC1 gene and are unable to efficiently repair DNA ssbs, were 3.7x and 4.5x more sensitive to NLCQ-1 and TPZ, respectively, than the parental AA8 cells. Similarly, UV41, which are defective in the ERCC4/XPF gene and thus, hypersensitive to DNA cross-linking agents, were 4.1x more sensitive than AA8 cells to NLCQ-1. Equitoxic concentrations of NLCQ-1 and TPZ gave similar numbers of ssbs in AA8 and EM9 cells exposed to each compound for 1 h under hypoxic conditions. In combination with L-PAM or cisPt, synergy was observed in AA8 but not in EM9 or UV41 cells, with either NLCQ-1 or TPZ. These results suggest that NLCQ-1 is involved in the formation of DNA ssbs and interstrand crosslinks, with the latter being most likely responsible for NLCQ-1 hypoxic toxicity. The synergistic interaction of NLCQ-1 with L-PAM or cisPt is probably due to an enhancement in the L-PAM/cisPt-induced DNA interstrand crosslinks, possibly as a result of an inhibited

Bed-material entrainment and associated transportation infrastructure problems in streams of the Edwards Plateau, central Texas

Science.gov (United States)

Heitmuller, Franklin T.; Asquith, William H.

2008-01-01

The Texas Department of Transportation commonly builds and maintains low-water crossings (LWCs) over streams in the Edwards Plateau in Central Texas. LWCs are low-height structures, typically constructed of concrete and asphalt, that provide acceptable passage over seasonal rivers or streams with relatively low normal-depth flow. They are designed to accommodate flow by roadway overtopping during high-flow events. The streams of the Edwards Plateau are characterized by cobble- and gravel-sized bed material and highly variable flow regimes. Low base flows that occur most of the time occasionally are interrupted by severe floods. The floods entrain and transport substantial loads of bed material in the stream channels. As a result, LWCs over streams in the Edwards Plateau are bombarded and abraded by bed material during floods and periodically must be maintained or even replaced.

External versus internal fixation for bicondylar tibial plateau fractures: systematic review and meta-analysis.

Science.gov (United States)

Metcalfe, David; Hickson, Craig J; McKee, Lesley; Griffin, Xavier L

2015-12-01

It is uncertain whether external fixation or open reduction internal fixation (ORIF) is optimal for patients with bicondylar tibial plateau fractures. A systematic review using Ovid MEDLINE, Embase Classic, Embase, AMED, the Cochrane Library, Open Grey, Orthopaedic Proceedings, WHO International Clinical Trials Registry Platform, Current Controlled Trials, US National Institute for Health Trials Registry, and the Cochrane Central Register of Controlled Trials. The search was conducted on 3rd October 2014 and no language limits were applied. Inclusion criteria were all clinical study designs comparing external fixation with open reduction internal fixation of bicondylar tibial plateau fractures. Studies of only one treatment modality were excluded, as were those that included unicondylar tibial plateau fractures. Treatment effects from studies reporting dichotomous outcomes were summarised using odds ratios. Continuous outcomes were converted to standardized mean differences to assess the treatment effect, and inverse variance methods used to combine data. A fixed effect model was used for meta-analyses. Patients undergoing external fixation were more likely to have returned to preinjury activities by six and twelve months (P = 0.030) but not at 24 months follow-up. However, external fixation was complicated by a greater number of infections (OR 2.59, 95 % CI 1.25-5.36, P = 0.01). There were no statistically significant differences in the rates of deep infection, venous thromboembolism, compartment syndrome, or need for re-operation between the two groups. Although external fixation and ORIF are associated with different complication profiles, both are acceptable strategies for managing bicondylar tibial plateau fractures.

Application of Minimally Invasive Treatment of Locking Compression Plate in Schatzker Ⅰ-Ⅲ Tibial Plateau Fracture

OpenAIRE

Guohui Zhao

2014-01-01

Objective: To investigate the clinical effect of minimally invasive treatment of locking compression plate (LCP) in Schatzker Ⅰ-Ⅲ tibial plateau fracture. Methods: Thirty-eight patients with Schatzker Ⅰ-Ⅲ tibial plateau fracture in our hospital were given minimally invasive treatment of LCP, and the artificial bone was transplanted to the depressed bone. Adverse responses, wound healing time and clinical efficacy were observed. Results: All patients were followed-up for 14- 20 months, and the...

Journal of Business and Administrative Studies - Vol 1, No 2 (2009)

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An assessment of the impact of tourism globalization in Africa · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. TPZ Mpofu, 1-19. http://dx.doi.org/10.4314/jbas.v1i2.57346 ...

New insights into trace elements deposition in the snow packs at remote alpine glaciers in the northern Tibetan Plateau, China.

Science.gov (United States)

Dong, Zhiwen; Kang, Shichang; Qin, Xiang; Li, Xiaofei; Qin, Dahe; Ren, Jiawen

2015-10-01

Trace element pollution resulting from anthropogenic emissions is evident throughout most of the atmosphere and has the potential to create environmental and health risks. In this study we investigated trace element deposition in the snowpacks at two different locations in the northern Tibetan Plateau, including the Laohugou (LHG) and the Tanggula (TGL) glacier basins, and its related atmospheric pollution information in these glacier areas, mainly focusing on 18 trace elements (Li, Be, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Nb, Mo, Cd, Sb, Cs, Ba, Tl, and Pb). The results clearly demonstrate that pronounced increases of both concentrations and crustal enrichment factors (EFs) are observed in the snowpack at the TGL glacier basin compared to that of the LHG glacier basin, with the highest EFs for Sb and Zn in the TGL basin, whereas with the highest EFs for Sb and Cd in the LHG basin. Compared with other studies in the Tibetan Plateau and surrounding regions, trace element concentration showed gradually decreasing trend from Himalayan regions (southern Tibetan Plateau) to the TGL basin (central Tibetan Plateau), and to the LHG basin (northern Tibetan Plateau), which probably implied the significant influence of atmospheric trace element transport from south Asia to the central Tibetan Plateau. Moreover, EF calculations at two sites showed that most of the heavy metals (e.g., Cu, Zn, Mo, Cd, Sb, and Pb) were from anthropogenic sources and some other elements (e.g., Li, Rb, and Ba) were mainly originated from crustal sources. MODIS atmospheric optical depth (AOD) fields derived using the Deep Blue algorithm and CALIOP/CALIPSO transect showed significant influence of atmospheric pollutant transport from south Asia to the Tibetan Plateau, which probably caused the increased concentrations and EFs of trace element deposition in the snowpack on the TGL glacier basin. Copyright © 2015 Elsevier B.V. All rights reserved.

3-D mechanical modeling of the eastward escape flow pattern around the Northeastern Tibetan plateau and surrounding regions

Science.gov (United States)

Cheng, H.; Shi, Y.; Zhang, H.

2016-12-01

Since the last 50 million years, 2500km shorting of Indian Plate moving north collided with the Eurasian Plate has resulted in rapid uplift of the Tibetan Plateau shaped into the most intensive and extensive orogen on earth (Molnar and Tapponnier, 1975; Li et al., 2013). Based on previous geological and geophysical investigations (Royden et al., 1997; Clark and Royden, 2000), two end-member models of the entire Tibetan Plateau are proposed: thin visous sheet model and lateral escape model. However, when we scope into a special local area, for example, Northeastern Tibetan plateau and surrounding regions, end-member models could change to lower crustal flow model and upper crust shorting model. Recently, with vigorous geophysical observations, more data such as differential traveltime tomography and seismic velocity structure in the Tibetan Plateau actually reveal that the eastward crustal flow from the central Tibetan plateau is expected to divert north-eastward and south-eastward around the rigid Sichuan basin (Royden et al., 1997, 2008; Clark and Royden, 2000). Moreover, both the P-wave polarization tomography and gravitational anomaly and the GPS data from the intensive crustal movement monitoring network in China show that the north-eastward crustal flow divide two direction due to the Ordos Block as a barrier with rigid, cold and stable crust. In order to investigate mechanical of the eastward escape flow pattern around the Northeastern Tibetan plateau and surrounding regions, especially along the Xi'an-Taiyuan-Datong, we construct 3-D geological finite element model with high resolution topography and non-homogeneous strata. For the uncertainties of computational parameters, such as the depth and width and viscosity coefficient of the middle-lower crust, and the pressure differences, several models were tested to analyze the spatial distribution of curst flow and try to known about the uplift of Datong in Shanxi Province.

Ethnobotanical survey of medicinal plants used in the treatment of animal diarrhoea in Plateau State, Nigeria.

Science.gov (United States)

Offiah, Nkechi V; Makama, Sunday; Elisha, Ishaku L; Makoshi, Micah S; Gotep, Jurbe G; Dawurung, Christiana J; Oladipo, Olusola O; Lohlum, Ann S; Shamaki, David

2011-07-11

The use of medicinal plants in the treatment of diseases has generated renewed interest in recent times, as herbal preparations are increasingly being used in both human and animal healthcare systems. Diarrhoea is one of the common clinical signs of gastrointestinal disorders caused by both infectious and non-infectious agents and an important livestock debilitating condition. Plateau State is rich in savannah and forest vegetations and home to a vast collection of plants upheld in folklore as having useful medicinal applications. There is however scarcity of documented information on the medicinal plants used in the treatment of animal diarrhoea in the state, thus the need for this survey. Ten (10) out of 17 Local Government Areas (LGAs), spread across the three senatorial zones were selected. Farmers were interviewed using well structured, open-ended questionnaire and guided dialogue techniques between October and December 2010. Medicinal plants reported to be effective in diarrhoea management were collected using the guided field-walk method for identification and authentication. A total of 248 questionnaires were completed, out of which 207 respondents (83.47%) acknowledged the use of herbs in diarrhoea management, while 41 (16.53%) do not use herbs or apply other traditional methods in the treatment of diarrhoea in their animals. Medicinal plants cited as beneficial in the treatment of animal diarrhoea numbered 132, from which 57(43.18%) were scientifically identified and classified into 25 plant families with the families Fabaceae (21%) and Combretaceae (14.04%) having the highest occurrence. The plant parts mostly used in antidiarrhoeal herbal preparations are the leaves (43.86%) followed by the stem bark (29.82%). The herbal preparations are usually administered orally. Rural communities in Plateau State are a rich source of information on medicinal plants as revealed in this survey. There is need to scientifically ascertain the authenticity of the claimed

Integrating Data of ASTER and Landsat-8 OLI (AO for Hydrothermal Alteration Mineral Mapping in Duolong Porphyry Cu-Au Deposit, Tibetan Plateau, China

Directory of Open Access Journals (Sweden)

Tingbin Zhang

2016-10-01

Full Text Available One of the most important characteristics of porphyry copper deposits (PCDs is the type and distribution pattern of alteration zones which can be used for screening and recognizing these deposits. Hydrothermal alteration minerals with diagnostic spectral absorption properties in the visible and near-infrared (VNIR through the shortwave infrared (SWIR regions can be identified by multispectral and hyperspectral remote sensing data. Six Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER bands in SWIR have been shown to be effective in the mapping of Al-OH, Fe-OH, Mg-OH group minerals. The five VNIR bands of Landsat-8 (L8 Operational Land Imager (OLI are useful for discriminating ferric iron alteration minerals. In the absence of complete hyperspectral coverage area, an opportunity, however, exists to integrate ASTER and L8-OLI (AO to compensate each other’s shortcomings in covering area for mineral mapping. This study examines the potential of AO data in mineral mapping in an arid area of the Duolong porphyry Cu-Au deposit(Tibetan Plateau in China by using spectral analysis techniques. Results show the following conclusions: (1 Combination of ASTER and L8-OLI data (AO has more mineral information content than either alone; (2 The Duolong PCD alteration zones of phyllic, argillic and propylitic zones are mapped using ASTER SWIR bands and the iron-bearing mineral information is best mapped using AO VNIR bands; (3 The multispectral integration data of AO can provide a compensatory data of ASTER VNIR bands for iron-bearing mineral mapping in the arid and semi-arid areas.

Angular-stable locking plate fixation of tibial plateau fractures-clinical and radiological midterm results in 101 patients

OpenAIRE

Sven Mardian; Felix Landmann; Florian Wichlas; Norbert P Haas; Klaus-Dieter Schaser; Philipp Schwabe

2015-01-01

Background: Articular reconstruction and stable fixation of tibial plateau fractures and its various subtypes continue to represent a surgical challenge. Only few trials have studied results following angular stable plate fixation. The present study aimed to investigate the clinical, radiological, functional and quality of life results following tibial plateau fractures using angular stable plate fixation. Materials and Methods: 101 patients were retrospectively studied using functional (...

Deformation of the southeast part of the Columbia Plateau

International Nuclear Information System (INIS)

Hooper, P.R.; Camp, V.E.

1981-01-01

Four structural elements north of the Olympic-Wallowa lineament in the southeast part of the Columbia Plateau (Washington, Idaho, and Oregon) are (1) the offlap of progressively younger basalt units from prebasalt topographic highs; (2) east-west open folds associated with reverse faulting; (3) northwest-southeast, northeast-southwest, and north-south faults with predominantly vertical displacement; and (4) vertical north-northwest-south-southeast feeder dikes. These may be explained by (1) a regional east to west tilting of the plateau caused by the isostatic rise of older rocks on the eastern margin; (2) a stress regime with a horizontal maximum principal stress in a north-northwest-south-southeast direction, and a horizontal minimum principal stress in a west-southwest-east-northeast direction; and (3) reactivation of an older northwest-southeast, northeast-southwest, and north-south structural grain in the pre-Miocene basement. The stress regime is similar to that envisaged for the area southwest of the Olympic-Wallowa lineament, and the difference in the type of deformation on either side of that feature may be attributed to differences in the thickness of the crust across the ancient boundary

Detours in long-distance migration across the Qinghai-Tibetan Plateau: individual consistency and habitat associations.

Science.gov (United States)

Liu, Dongping; Zhang, Guogang; Jiang, Hongxing; Lu, Jun

2018-01-01

Migratory birds often follow detours when confronted with ecological barriers, and understanding the extent and the underlying drivers of such detours can provide important insights into the associated cost to the annual energy budget and the migration strategies. The Qinghai-Tibetan Plateau is the most daunting geographical barrier for migratory birds because the partial pressure of oxygen is dramatically reduced and flight costs greatly increase. We analyzed the repeated migration detours and habitat associations of four Pallas's Gulls Larus ichthyaetus across the Qinghai-Tibetan Plateau over 22 migration seasons. Gulls exhibited notable detours, with the maximum distance being more than double that of the expected shortest route, that extended rather than reduced the passage across the plateau. The extent of longitudinal detours significantly increased with latitude, and detours were longer in autumn than in spring. Compared with the expected shortest routes, proximity to water bodies increased along autumn migration routes, but detour-habitat associations were weak along spring migration routes. Thus, habitat availability was likely one, but not the only, factor shaping the extent of detours, and migration routes were determined by different mechanisms between seasons. Significant between-individual variation but high individual consistency in migration timing and routes were revealed in both seasons, indicating a stronger influence of endogenous schedules than local environmental conditions. Gulls may benefit from repeated use of familiar routes and stopover sites, which may be particularly significant in the challenging environment of the Qinghai-Tibetan Plateau.

Quantum critical behaviour of the plateau-insulator transition in the quantum Hall regime

International Nuclear Information System (INIS)

Visser, A de; Ponomarenko, L A; Galistu, G; Lang, D T N de; Pruisken, A M M; Zeitler, U; Maude, D

2006-01-01

High-field magnetotransport experiments provide an excellent tool to investigate the plateau-insulator phase transition in the integral quantum Hall effect. Here we review recent low-temperature high-field magnetotransport studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs quantum well. We find that the longitudinal resistivity ρ xx near the critical filling factor ν c ∼ 0.5 follows the universal scaling law ρ xx (ν, T) ∝ exp(-Δν/(T/T 0 ) κ ), where Δν = ν-ν c . The critical exponent κ equals 0.56 ± 0.02, which indicates that the plateau-insulator transition falls in a non-Fermi liquid universality class

Land–biosphere–atmosphere interactions over the Tibetan plateau from MODIS observations

International Nuclear Information System (INIS)

Jin, Menglin S; Mullens, Terrence J

2012-01-01

Eleven years (2000–10) of monthly observations from the National Aeronautics and Space Administration (NASA) Terra Moderate-resolution Imaging Spectroradiometer (MODIS) show the diurnal, seasonal, and inter-annual variations of skin temperature over the Tibetan plateau (75–100°E, 27–45°N) at 0.05° × 0.05° resolution. A slight warming trend is observed during this period of time, although the relatively short duration of the observation makes such a trend uncertain. More importantly, using the most recent climatology of land skin temperature, spatially high correlation coefficients are found among normalized difference vegetation index (NDVI), water vapor and cloud relations, indicating that the land surface, vegetation and atmosphere influence one another. Such a quantitative understanding of these relationships at high spatial resolution would be helpful for modeling the biosphere–atmosphere–land surface interaction processes over the Tibetan plateau. (letter)

Evaluating the coupling effects of climate aridity and vegetation restoration on soil erosion over the Loess Plateau in China.

Science.gov (United States)

Zhang, Baoqing; He, Chansheng; Burnham, Morey; Zhang, Lanhui

2016-01-01

In this study, the coupling effects of climate aridity and vegetation restoration on runoff and sediment yield over the Loess Plateau were examined and characterized. To take into consideration the complexity of drought, as well as the varied strengths and weaknesses of different drought measures, two drought indices are selected to identify and evaluate drought variability. The Normalized Difference Vegetation Index (NDVI) data were obtained to monitor and express spatiotemporal variations in vegetation cover. The results show that most regions of the Loess Plateau experienced increasingly severe droughts over the past 40years, and these regions comprise the major source of the Yellow River sediment. Climatic drying initially occurred in the 1990s, and became statistically significant in 2000s. The increasingly severe droughts could negatively impact surface and groundwater supplies as well as soil water storage, but may also minimize surface runoff yield, which is one of the major causes of soil erosion on the Loess Plateau. Vegetation cover on the Loess Plateau was significantly improved after the implementation of "Grain for Green" project, which were helpful for controlling severe soil erosion. With the impacts of the construction of check dams, terraces and large reservoirs, runoff and sediment yield over the Loess Plateau initially exhibited downward trends between 1970 and 1990. After 1990, with the effects of the climate warming and drying, a second sharp reduction in runoff and sediment yield occurred. The coupling effects of climate aridity and vegetation restoration have led to a third significant decrease in runoff and sediment yield over the Loess Plateau after 2000. Copyright © 2015 Elsevier B.V. All rights reserved.

Prevalence of Gastro-Intestinal Parasites of Pigs in Jos, Plateau ...

African Journals Online (AJOL)

There is a growing concern for pig parasites as a bottleneck for low productivity and reduction in the market value of pork meat. The economic losses resulting from gastrointestinal parasites of pigs are quite enormous. This study was designed to investigate the prevalence of gastrointestinal parasites of pigs in Jos Plateau ...

Protozoan Diversity in a productive fishpond of a tropical plateau ...

African Journals Online (AJOL)

A survey of the Protozoan species diversity in a productive fishpond of the Jos Plateau, Nigeria was investigated at 7 day interval over a period of 11 months. Samples were collected from water column and sediment. Protozoans were found to compose of the flagellates sarcodines and cilliates. There was a significant ...

Long-term Outcome of Argon Laser Peripheral Iridoplasty in the Management of Plateau Iris Syndrome Eyes.

Science.gov (United States)

Peterson, Jeffrey R; Anderson, John W; Blieden, Lauren S; Chuang, Alice Z; Feldman, Robert M; Bell, Nicholas P

2017-09-01

To report long-term (>5 y) outcomes of plateau iris syndrome patients treated with argon laser peripheral iridoplasty (ALPI). A retrospective chart review was performed on all patients with plateau iris syndrome treated with ALPI from 1996 to 2007. The study included 22 eyes from 22 patients with plateau iris after peripheral iridotomy that were followed for at least 1 year after ALPI. The primary outcome was incidence of needing any intraocular pressure (IOP)-lowering medications or surgery (either a filtering procedure or phacoemulsification). Demographic and baseline clinical data were summarized by mean (±SD) or frequency (percentage). Snellen best-corrected visual acuity was converted to logMAR. The paired t test was used to compare IOP changes, number of IOP-lowering medications, and best-corrected visual acuity from baseline to annual follow-up. Mean follow-up was 76 months. Only 2 (9%) eyes maintained an IOPiris in our patient population.

Zone separator for multiple zone vessels

Science.gov (United States)

Jones, John B.

1983-02-01

A solids-gas contact vessel, having two vertically disposed distinct reaction zones, includes a dynamic seal passing solids from an upper to a lower zone and maintaining a gas seal against the transfer of the separate treating gases from one zone to the other, and including a stream of sealing fluid at the seal.

Signals of pollution revealed by trace elements in recent snow from mountain glaciers at the Qinghai-Tibetan plateau.

Science.gov (United States)

Li, Yuefang; Li, Zhen; Cozzi, Giulio; Turetta, Clara; Barbante, Carlo; Huang, Ju; Xiong, Longfei

2018-06-01

In order to extract pollution signal of trace elements (TEs) in glacier snow at the Qinghai-Tibetan plateau of China by human activities, concentrations of 18 TEs (Al, Ti, Fe, Rb, Sr, Ba, V, Cr, Mn, Li, Cu, Co, Mo, Cs, Sb, Pb, Tl, and U), 14 rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), Y and Th in digested snow samples from five glaciers in April-May 2013 before monsoon season were measured. Results shown that higher TEs concentrations were found in glaciers at the northern plateau while lower concentrations in glaciers at the central and southern plateau. Discussion revealed that EF values calculated from elements with mass fraction TEs such as Sb, Sr, As, Cu and Pb etc. Analysis indicated that most TEs mainly originated from dust sources, whereas Pb, Cu, Mo and Sb showed occasionally significant contributions from polluted sources in three snow pits and the GRHK surface snow samples. The pollution probably originated from mining and smelting, road transport emissions on the plateau and some regions outside of the plateau. Dust provenance tracing results based on REEs indicated that Taklimakan Desert, Qaidam Basin, and Tibetan surface soil were the potential dust sources for the studied glaciers, while the Indian Thar Desert was an occasional dust sources for YZF,XDKMD and GRHK snow samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Holocene monsoon variability inferred from Targo Xian peat bog in the Tangra Yumco basin, central Tibetan Plateau

Science.gov (United States)

Henkel, Karoline; Haberzettl, Torsten; Miehe, Sabine; Frenzel, Peter; Daut, Gerhard; Dietze, Elisabeth; Kasper, Thomas; Ahlborn, Marieke; Mäusbacher, Roland

2013-04-01

The Tibetan Plateau is the greatest plateau on Earth with an average altitude of 4,500 m asl. Due to its high elevation, large area and significant role in the formation of the Asian Monsoon Systems (e.g., Indian Ocean and East-Asian Summer Monsoon) it is considered to react very sensitive to climate variations. The numerous lake systems on the Tibetan Plateau represent excellent archives reflecting variations in the strength of the monsoon system in terms of hydrological changes expressed in lake level fluctuations. For example, terraces and lacustrine deposits around the saline lake Tangra Yumco indicate lake level highstands up to ~215 m higher than the present lake level. To study Holocene lake level variations we investigated a 3.6 m long sediment core recovered from a peat bog (near the Targo Xian settlement, 30°46'N, 86°40'E) on a recessional lake level terrace ~150 m above the present shoreline of Tangra Yumco. In particular, our analyses of sedimentological (grain size), geochemical (CNS and ICP-OES) and mineralogical (XRD) data allow a detailed and high-resolution interpretation of the hydrological conditions during the Holocene. The existence of two carbonate layers in the Targo Xian record, separated by a sand layer and intercalated in peat sequences at the bottom and top of the core, provide evidence for two stable lake stages at the coring position. Peat at the bottom of the core, which is radiocarbon-dated to 11,130 +130/-345 cal BP, indicates wetland conditions similar to the Recent situation (Miehe et al., submitted). After a transition zone, a layer of pure aragonitic lake marl gives evidence for a lake stage. During this stage, high values of the total inorganic carbon (TIC) and Ca/Ti ratios as well as low C/N ratios point to a stable lake due to wet climatic conditions. This carbonate layer can be correlated with a 2-3 m thick carbonate layer found in outcrops around the present lake Tangra Yumco presenting a high lake level until approx. 2

Using a Coupled Human-Natural System to Assess the Vulnerability of the Karst Landform Region in China

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Xiang He

2015-09-01

Full Text Available Guizhou Plateau is a region in China that typically shows the contradictory human-earth system. A vulnerability assessment indicator system was constructed to explore the coupled human-natural system characteristic of the karst landform based on the grey correlation analysis mathematic model. The quantitative assessment results show that Qiandongnan and Tongren Districts belong to the slight degree of the sensitivity evaluation index. Bijie district belongs to the middle degree and the other districts of Guizhou Plateau belong to the light degree. In terms of the exposure and resilience evaluation index, only Guiyang City belongs to the slight degree and other districts are in the middle degree. Thus, Guizhou Plateau could be divided into three level zones based on the comprehensive vulnerability degree of the coupled human-natural system. The strong degree vulnerability zone includes Liupanshui City, Bijie City, Anshun City, and Qiannan District. The middle degree vulnerability zone includes the districts of Qiandongnan, Qianxinan, and Tongren and the city of Zunyi. The slight degree vulnerability zone only includes Guiyang City. The research results suggest that the coupled human-natural system in Guizhou Plateau has a high vulnerability.

Qinghai-Tibet Plateau crustal thickness derived from EGM2008 and CRSUT2.0

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Zhou Hao

2014-11-01

Full Text Available Qinghai-Tibet Plateau is the most complex region for crustal thickness inversion, while high-resolution earth gravity model (EGM makes it possible to obtain high precision gravity anomaly, which is a key parameter to depict the Earth’s inner structure in geodesy domain. On the basis of this principle, we calculated the Bouguer gravity anomalies in Qinghai-Tibet Plateau with EGM2008 and SRTM6. 0 by efficient high-degree spherical harmonic synthesis algorithm. In order to obtain the gravity anomaly caused by Moho density mutant, the noises caused by the topography was removed by wavelet details. Then, the crustal thickness was corrected on the basis of CRUST 2. 0 with the deep-large-scale single density interface formula. The inversion result indicates that the crustal thickness in Qinghai-Tibet Plateau is between 50 km and 75 km, which is in correspondence with the recent science research result. Compared with the 2 degree CRUST 2. 0 model, the spatial resolution of crustal thickness in our research can reach 40 arc minutes. In addition, there is a positive relationship between the inversed crustal thickness and topography, which can prove the effectiveness of Airy-Heiskanen isostatic model in gravity reduction.

The vascular flora of the Tepoš plateau around Pirot city (Eastern Serbia

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Jotić, B.

2013-12-01

Full Text Available The flora of the karst plateau Tepoš, which is the part of Vidlič mountain (eastern Serbia was studied. Based on the analysis of the collected material and data from the literature, it was noted that the flora of Tepoš plateau is represented by 486 species, distributed in 284 genera and 68 families of vascular plants. The biological spectra was shown. The hemicriptophytic-terophytic character was established by analyzing the presence of plant life forms. By phytogeographical analysis the presence of 25 area types was established. The euroasian florystic chorion with 258 species of eurasian area type is the most abundant, followed by mediterranean-submediterranean (58 species, central-european (47 species, cosmopolitan (27 species and pontian area type (24 species. In the flora of Tepoš plateau the 9 balkan endemic taxa were recorded, which is 3,14% of total balkan endemic taxa in flora of Serbia. A small number of endemic taxa is expected, considering the low diversity of habitats. Balkan endemic taxa recorded in this area are: Acer hyrcanum subsp. intermedium, Bupleurum flavicans, Crucianella graeca, Eryngium palmatum, Pastinaca hirsuta, Hypericum rumeliacum subsp. rumeliacum, Thymus praecox subsp. jankae, Linaria rubioides subsp. nissana and Viola tricolor subsp. macedonica.

Fractal Feature of Particle-Size Distribution in the Rhizospheres and Bulk Soils during Natural Recovery on the Loess Plateau, China

Science.gov (United States)

Song, Zilin; Zhang, Chao; Liu, Guobin; Qu, Dong; Xue, Sha

2015-01-01

The application of fractal geometry to describe soil structure is an increasingly useful tool for better understanding the performance of soil systems. Only a few studies, however, have focused on the structure of rhizospheric zones, where energy flow and nutrient recycling most frequently occur. We used fractal dimensions to investigate the characteristics of particle-size distribution (PSD) in the rhizospheres and bulk soils of six croplands abandoned for 1, 5, 10, 15, 20, and 30 years on the Loess Plateau of China and evaluated the changes over successional time. The PSDs of the rhizospheres and the fractal dimensions between rhizosphere soil and bulk soils during the natural succession differed significantly due to the influence of plant roots. The rhizospheres had higher sand (0.05–1.00 mm) contents, lower silt (soils during the early and intermediate successional stages (1–15 years). The fractal dimensions of the rhizosphere soil and bulk soil ranged from 2.102 to 2.441 and from 2.214 to 2.459, respectively, during the 30-year restoration. Rhizospheric clay and silt contents and fractal dimension tended to be higher and sand content tended to be lower as abandonment age increased, but the bulk soils had the opposite trend. Linear regression analysis indicated that the fractal dimensions of both the rhizospheres and bulk soils were significantly linearly correlated with clay, sand, organic-carbon, and total-nitrogen contents, with R 2 ranging from 0.526 to 0.752 (Psoil and bulk soil. The fractal dimension was a sensitive and useful index for quantifying changes in the properties of the different soil zones. This study will greatly aid the application of the fractal method for describing soil structure and nutrient status and the understanding of the performance of rhizospheric zones during ecological restoration. PMID:26368339

The melt inclusion record from the rhyolitic Kos Plateau Tuff (Aegean Arc)

Science.gov (United States)

Bachmann, Olivier; Wallace, Paul J.; Bourquin, Julie

2010-02-01

The >60 km3 rhyolitic Kos Plateau Tuff provides an exceptional probe into the behavior of volatile components in highly evolved arc magmas: it is crystal-rich (30-40 vol% crystals), was rapidly quenched by the explosive eruptive process, and contains abundant homogeneous melt inclusions in large quartz crystals. Several methods for measuring major, trace and volatile element concentrations (SIMS, FTIR, Raman spectroscopy, electron microprobe, LA-ICPMS) were applied to these melt inclusions. We found a ~2 wt% range of H2O contents (4.5-6.5 wt% H2O, measured independently by SIMS, FTIR, and Raman spectroscopy) and relatively low CO2 concentrations (15-140 ppm measured by FTIR, with most analyses <100 ppm). No obvious correlations between H2O, CO2, major and trace elements are observed. These observations require a complex, protracted magma evolution in the upper crust that included: (1) vapor-saturated crystallization in a chamber located between 1.5 and 2.5 kb pressure, (2) closed-system degassing (with up to 10 vol% exsolved gas) as melts percolated upwards through a vertically extensive mush zone (2-4 km thick), and (3) periodic gas fluxing from subjacent, more mafic and more CO2-rich magma, which is preserved as andesite bands in pumices. These processes can account for the range of observed H2O and CO2 values and the lack of correlation between volatiles and trace elements in the melt inclusions.

Study on Sr-Nd isotopes of mesozoic-cenozoic granites in Qinghai-Tibetan plateau

International Nuclear Information System (INIS)

Qiu Ruizhao; Deng Jinfu; Zhou Su; Xiao Qinghui; Cai Zhiyong

2003-01-01

Mesozoic-Cenozoic magmatic activities were intensive in Qinghai-Tibetan plateau. Nd-Sr isotopic compositions of representative granitic plutons in western Qinghai-Tibetan plateau are reported in this paper. Combining with past isotopic data, which has reported in eastern Qinghai-Tibetan plateau, Sr-Nd isotopic compositions and material source and genesis of Mesozoic and Cenozoic granites in Qinghai-Tibetan plateau have been studied. The research result indicates there are three types of granite existing in Qinghai-Tibetan plateau, the granites of Late stage of Yanshan Period which distributing on north and south boundary of Gandes block (namely in north and south granitic belts of Dangdes) and cause of oceanic crust subduction, have ( 87 Sr/ 86 Sr)i of 0.7041-0.7064, ε (Nd) t of +2.5 - +5.7 and TDM age of 312-562 Ma, positive ε Nd, low ( 87 Sr/ 86 Sr)i ratio and young Nd model ages suggest relatively high contents of mantle-derived components in their sources, and this type granite might melt from subduction oceanic crust. The granites occurred intra-Gangdes block which were caused by collision of continent and post-collision, have ( 87 Sr/ 86 Sr)i of 0.706-0.719, ε (Nd) t of -5.3 - -8.3 and TDM age of 1323-1496 Ma, negative ε Nd, relative high ( 87 Sr/ 86 Sr)i ratio with an mid-Proterozoic Nd model ages, suggest granite has the mixing genesis of mantle-derived components and old crustal components in their sources. With relatively small variation range in ε (Nd) t and TDM age, it might imply granitic isotopic source in Gandes block to keep relative homogenization in long period. The granites in Himalayan block which there is not oceanic material to join in melting and to cause of intra-continental subduction, has most ( 87 Sr/ 86 Sr)i ratio more than 0.720, ε (Nd) t of -10.3 - -16.3 and TDM age of 1792-2206 Ma, high ( 87 Sr/ 86 Sr)i ratio, low negative ε (Nd)t with old Nd isotopic model ages and consistent with the Sr, Nd isotopic compositions of basement

Plateau properties in mammalian spinal interneurons during transmitter-induced locomotor activity

DEFF Research Database (Denmark)

Kiehn, O.; Johnson, B. R.; Raastad, M.

1996-01-01

We examined the organization of spinal networks controlling locomotion in the isolated spinal cord of the neonatal rat, and in this study we provide the first demonstration of plateau and bursting mechanisms in mammalian interneurons that show locomotor-related activity. Using tight-seal whole...

Prolonged operative time increases infection rate in tibial plateau fractures.

Science.gov (United States)

Colman, Matthew; Wright, Adam; Gruen, Gary; Siska, Peter; Pape, Hans-Christoph; Tarkin, Ivan

2013-02-01

Fractures of the tibial plateau present a treatment challenge and are susceptible to both prolonged operative times and high postoperative infection rates. For those fractures treated with open plating, we sought to identify the relationship between surgical site infection and prolonged operative time as well as to identify other surgical risk factors. We performed a retrospective controlled analysis of 309 consecutive unicondylar and bicondylar tibial plateau fractures treated with open plate osteosynthesis at our institution's level I trauma centre during a recent 5-year period. We recorded operative times, injury characteristics, surgical treatment, and need for operative debridement due to infection. Operative times of infected cases were compared to uncomplicated surgical cases. Multivariable logistic regression analysis was performed to identify independent risk factors for postoperative infection. Mean operative time in the infection group was 2.8h vs. 2.2h in the non-infected group (p=0.005). 15 fractures (4.9%) underwent four compartment fasciotomies as part of their treatment, with a significantly higher infection rate than those not undergoing fasciotomy (26.7% vs. 6.8%, p=0.01). Open fracture grade was also significantly related to infection rate (closed fractures: 5.3%, grade 1: 14.3%, grade 2: 40%, grade 3: 50%, pinfection rates (13.9% vs. 8.7%, p=0.36). Multivariable logistic regression analysis of the entire study group identified longer operative times (OR 1.78, p=0.013) and open fractures (OR 7.02, psite infection. Operative times approaching 3h and open fractures are related to an increased overall risk for surgical site infection after open plating of the tibial plateau. Dual incision approaches with bicolumnar plating do not appear to expose the patient to increased risk compared to single incision approaches. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants.

Science.gov (United States)

Zhong, Rui; Liu, Hua; Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin

2015-01-01

Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants

Science.gov (United States)

Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin

2015-01-01

Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated. PMID:26637115

Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants.

Directory of Open Access Journals (Sweden)

Rui Zhong

Full Text Available Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb and hematocrit (Hct, which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP, which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG and oxygen tension to attain 50% oxygen saturation of Hb (P50 in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.

Discovery of cryptic Armillaria solidipes genotypes within the Colorado Plateau

Science.gov (United States)

J. W. Hanna; N. B. Klopfenstein; M. -S. Kim; S. M. Ashiglar; A. L. Ross-Davis; G. I. McDonald

2012-01-01

Armillaria solidipes (= A. ostoyae) is a root-disease pathogen that causes severe losses in growth and productivity of forest trees throughout the Northern Hemisphere. This species is genetically diverse with variable disease activities across different regions of the world. In North America, A. solidipes in the Colorado Plateau exists in drier habitats and causes more...

Soil Nitrogen Storage, Distribution, and Associated Controlling Factors in the Northeast Tibetan Plateau Shrublands

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Xiuqing Nie

2017-11-01

Full Text Available Although the soils in the Tibetan Plateau shrublands store large amounts of total nitrogen (N, the estimated values remain uncertain because of spatial heterogeneity and a lack of field observations. In this study, we quantified the regional soil N storage, spatial and vertical density distributions, and related climatic controls using 183 soil profiles sampled from 61 sites across the Northeast Tibetan Plateau shrublands during the period of 2011–2013. Our analysis revealed a soil N storage value of 132.40 Tg at a depth of 100 cm, with an average density of 1.21 kg m−2. Soil N density was distributed at greater levels in alpine shrublands, compared with desert shrublands. Spatially, soil N densities decreased from south to north and from east to west, and, vertically, the soil N in the upper 30 and 50 cm accounted for 42% and 64% of the total soil N stocks in the Tibetan Plateau. However, compared with desert shrublands, the surface layers in alpine shrublands exhibited a larger distribution of soil N stocks. Overall, the soil N density in the top 30 cm increased significantly with the mean annual precipitation (MAP and tended to decrease with the mean annual temperature (MAT, although the dominant climatic controls differed among shrubland types. Specifically, MAP in alpine shrublands, and MAT in desert shrubland, had a weak effect on N density. Soil pH can significant affect soil N density in the Tibetan Plateau shrublands. In conclusion, changes in soil N density should be monitored over the long term to provide accurate information about the effects of climatic factors.

The link between Tibetan Plateau monsoon and Indian summer precipitation: a linear diagnostic perspective

Science.gov (United States)

Ge, Fei; Sielmann, Frank; Zhu, Xiuhua; Fraedrich, Klaus; Zhi, Xiefei; Peng, Ting; Wang, Lei

2017-12-01

The thermal forcing of the Tibetan Plateau (TP) is analyzed to investigate the formation and variability of Tibetan Plateau Summer Monsoon (TPSM), which affects the climates of the surrounding regions, in particular the Indian summer monsoon precipitation. Dynamic composites and statistical analyses indicate that the Indian summer monsoon precipitation is less/greater than normal during the strong/weak TPSM. Strong (weak) TPSM is associated with an anomalous near surface cyclone (anticyclone) over the western part of the Tibetan Plateau, enhancing (reducing) the westerly flow along its southern flank, suppressing (favoring) the meridional flow of warm and moist air from the Indian ocean and thus cutting (providing) moisture supply for the northern part of India and its monsoonal rainfall. These results are complemented by a dynamic and thermodynamic analysis: (i) A linear thermal vorticity forcing primarily describes the influence of the asymmetric heating of TP generating an anomalous stationary wave flux. Composite analysis of anomalous stationary wave flux activity (after Plumb in J Atmos Sci 42:217-229, 1985) strongly indicate that non-orographic effects (diabatic heating and/or interaction with transient eddies) of the Tibetan Plateau contribute to the generation of an anomalous cyclone (anti-cyclone) over the western TP. (ii) Anomalous TPSM generation shows that strong TPSM years are related to the positive surface sensible heating anomalies over the eastern TP favoring the strong diabatic heating in summer. While negative TPSM years are associated with the atmospheric circulation anomalies during the preceding spring, enhancing northerly dry-cold air intrusions into TP, which may weaken the condensational heat release in the middle and upper troposphere, leading to a weaker than normal summer monsoon over the TP in summer.

Dendrochronological potential of the alpine shrub Rhododendron nivale on the south-eastern Tibetan Plateau.

Science.gov (United States)

Liang, Eryuan; Eckstein, Dieter

2009-09-01

Shrubs and dwarf shrubs are wider spread on the Tibetan Plateau than trees and hence offer a unique opportunity to expand the present dendrochronological network into extreme environments beyond the survival limit of trees. Alpine shrublands on the Tibetan Plateau are characterized by rhododendron species. The dendrochronological potential of one alpine rhododendron species and its growth response to the extreme environment on the south-east Tibetan Plateau were investigated. Twenty stem discs of the alpine snowy rhododendron (Rhododendron nivale) were collected close to the tongue of the Zuoqiupu Glacier in south-east Tibet, China. The skeleton plot technique was used for inter-comparison between samples to detect the growth pattern of each stem section. The ring-width chronology was developed by fitting a negative exponential function or a straight line of any slope. Bootstrapping correlations were calculated between the standard chronology and monthly climate data. The wood of snowy rhododendron is diffuse-porous with evenly distributed small-diameter vessels. It has well-defined growth rings. Most stem sections can be visually and statistically cross-dated. The resulting 75-year-long standard ring-width chronology is highly correlated with a timberline fir chronology about 200 km apart, providing a high degree of confidence in the cross-dating. The climate/growth association of alpine snowy rhododendron and of this timberline fir is similar, reflecting an impact of monthly mean minimum temperatures in November of the previous year and in July during the year of ring formation. The alpine snowy rhododendron offers new research directions to investigate the environmental history of the Tibetan Plateau in those regions where up to now there was no chance of applying dendrochronology.

Holocene debris flows on the Colorado Plateau: The influence of clay mineralogy and chemistry

Science.gov (United States)

Webb, R.H.; Griffiths, P.G.; Rudd, L.P.

2008-01-01

Holocene debris flows do not occur uniformly on the Colorado Plateau province of North America. Debris flows occur in specific areas of the plateau, resulting in general from the combination of steep topography, intense convective precipitation, abundant poorly sorted material not stabilized by vegetation, and the exposure of certain fine-grained bedrock units in cliffs or in colluvium beneath those cliffs. In Grand and Cataract Canyons, fine-grained bedrock that produces debris flows contains primarily single-layer clays - notably illite and kaolinite - and has low multilayer clay content. This clay-mineral suite also occurs in the colluvium that produces debris flows as well as in debris-flow deposits, although unconsolidated deposits have less illite than the source bedrock. We investigate the relation between the clay mineralogy and major-cation chemistry of fine-grained bedrock units and the occurrence of debris flows on the entire Colorado Plateau. We determined that 85 mapped fine-grained bedrock units potentially could produce debris flows, and we analyzed clay mineralogy and major-cation concentration of 52 of the most widely distributed units, particularly those exposed in steep topography. Fine-grained bedrock units that produce debris flows contained an average of 71% kaolinite and illite and 5% montmorillonite and have a higher concentration of potassium and magnesium than nonproducing units, which have an average of 51% montmorillonite and a higher concentration of sodium. We used multivariate statistics to discriminate fine-grained bedrock units with the potential to produce debris flows, and we used digital-elevation models and mapped distribution of debris-flow producing units to derive a map that predicts potential occurrence of Holocene debris flows on the Colorado Plateau. ?? 2008 Geological Society of America.

Snow effects on alpine vegetation in the Qinghai-Tibetan Plateau

Science.gov (United States)

Wang, Kun; Zhang, Li; Qiu, Yubao; Ji, Lei; Tian, Feng; Wang, Cuizhen; Wang, Zhiyong

2013-01-01

Understanding the relationships between snow and vegetation is important for interpretation of the responses of alpine ecosystems to climate changes. The Qinghai-Tibetan Plateau is regarded as an ideal area due to its undisturbed features with low population and relatively high snow cover. We used 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) datasets during 2001–2010 to examine the snow–vegetation relationships, specifically, (1) the influence of snow melting date on vegetation green-up date and (2) the effects of snow cover duration on vegetation greenness. The results showed that the alpine vegetation responded strongly to snow phenology (i.e., snow melting date and snow cover duration) over large areas of the Qinghai-Tibetan Plateau. Snow melting date and vegetation green-up date were significantly correlated (p growth was influenced by different seasonal snow cover durations (SCDs) in different regions. Generally, the December–February and March–May SCDs played a significantly role in vegetation growth, both positively and negatively, depending on different water source regions. Snow's positive impact on vegetation was larger than the negative impact.

Climate change on the Tibetan Plateau in response to shifting atmospheric circulation since the LGM

Science.gov (United States)

Zhu, Liping; Lü, Xinmiao; Wang, Junbo; Peng, Ping; Kasper, Thomas; Daut, Gerhard; Haberzettl, Torsten; Frenzel, Peter; Li, Quan; Yang, Ruimin; Schwalb, Antje; Mäusbacher, Roland

2015-01-01

The Tibetan Plateau (TP) is primarily influenced by the northern hemispheric middle latitude Westerlies and the Indian summer monsoon (ISM). The extent, long-distance effects and potential long-term changes of these two atmospheric circulations are not yet fully understood. Here, we analyse modern airborne pollen in a transition zone of seasonally alternating dominance of the Westerlies and the ISM to develop a pollen discrimination index (PDI) that allows us to distinguish between the intensities of the two circulation systems. This index is applied to interpret a continuous lacustrine sedimentary record from Lake Nam Co covering the past 24 cal kyr BP to investigate long-term variations in the atmospheric circulation systems. Climatic variations on the central TP widely correspond to those of the North Atlantic (NA) realm, but are controlled through different mechanisms resulting from the changing climatic conditions since the Last Glacial Maximum (LGM). During the LGM, until 16.5 cal kyr BP, the TP was dominated by the Westerlies. After 16.5 cal kyr BP, the climatic conditions were mainly controlled by the ISM. From 11.6 to 9 cal kyr BP, the TP was exposed to enhanced solar radiation at the low latitudes, resulting in greater water availability. PMID:26294226

Thickening the outer margins of the Tibetan Plateau: The role of crustal shortening

Science.gov (United States)

Lease, R. O.; Burbank, D. W.

2012-12-01

One of the most direct consequences of the collision of two buoyant continents is large-scale crustal thickening that results in the upward and outward growth of high terrain. As the stronger Indian continent has collided with weaker Asia over at least the past 50 Myr, widespread crustal thickening has occurred over an area that is approximately 2.5 million km^2 at present. The resultant Tibetan crust is the thickest observed on Earth today with an average thickness of 65 km and a maximum that may reach 90 km in places. The mechanisms by which Tibetan crust has thickened, however, as well as the timing and distribution of these mechanisms across the plateau, remain debatable. Two of the most popular mechanisms for thickening the crust beneath the margins of the Tibetan Plateau are: 1) pure shear with faulting and folding in the upper crust and horizontal shortening below; and 2) flow and inflation of lower or middle crust without significant shortening of the upper crust. To help discriminate between the relative contributions of these two mechanisms, well-constrained estimates of upper crustal shortening are needed. Here we document the Cenozoic shortening budget across the northeastern Tibetan Plateau margin near 36°N 102.5°E with several 100- to 145-km-long balanced cross sections. Thermochronological and magnetostratigraphic data indicate that modest NNE-SSW shortening began in middle Eocene time, shortly after initial India-Asia collision. Accelerated east-west shortening, however, did not commence until ~35 Myr later. A five-fold acceleration in shortening rates in middle Miocene-to-Recent time accounts for more than half of the total Cenozoic crustal shortening and thickening in this region. Overall, the balanced cross sections indicate 11 ± 2 % east-west shortening since middle Miocene time, and ~9 ± 2 % NNE-SSW shortening between middle Eocene and middle Miocene times. Given the present-day crustal thickness of 56 ± 4 km in northeastern Tibet, crustal

Parapapillary atrophy: histological gamma zone and delta zone.

Directory of Open Access Journals (Sweden)

Jost B Jonas

Full Text Available BACKGROUND: To examine histomorphometrically the parapapillary region in human eyes. METHODOLOGY/PRINCIPAL FINDINGS: The histomorphometric study included 65 human globes (axial length:21-37 mm. On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME-optic nerve margin ("Gamma zone", BME-retinal pigment epithelium (RPE ("Beta zone", BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm was significantly (P = 0.01 larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28 associated with axial length. Beta zone was significantly (P = 0.004 larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm was associated with axial length (P50 µm diameter within gamma zone was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

Impacts of the active layer on runoff in an upland permafrost basin, northern Tibetan Plateau.

Science.gov (United States)

Gao, Tanguang; Zhang, Tingjun; Guo, Hong; Hu, Yuantao; Shang, Jianguo; Zhang, Yulan

2018-01-01

The paucity of studies on permafrost runoff generation processes, especially in mountain permafrost, constrains the understanding of permafrost hydrology and prediction of hydrological responses to permafrost degradation. This study investigated runoff generation processes, in addition to the contribution of summer thaw depth, soil temperature, soil moisture, and precipitation to streamflow in a small upland permafrost basin in the northern Tibetan Plateau. Results indicated that the thawing period and the duration of the zero-curtain were longer in permafrost of the northern Tibetan Plateau than in the Arctic. Limited snowmelt delayed the initiation of surface runoff in the peat permafrost in the study area. The runoff displayed intermittent generation, with the duration of most runoff events lasting less than 24 h. Precipitation without runoff generation was generally correlated with lower soil moisture conditions. Combined analysis suggested runoff generation in this region was controlled by soil temperature, thaw depth, precipitation frequency and amount, and antecedent soil moisture. This study serves as an important baseline to evaluate future environmental changes on the Tibetan Plateau.

On the relationship between the early spring Indian Ocean's sea surface temperature (SST) and the Tibetan Plateau atmospheric heat source in summer

Science.gov (United States)

Ji, Chenxu; Zhang, Yuanzhi; Cheng, Qiuming; Li, Yu; Jiang, Tingchen; San Liang, X.

2018-05-01

In this study, we evaluated the effects of springtime Indian Ocean's sea surface temperature (SST) on the Tibetan Plateau's role as atmospheric heat source (AHS) in summer. The SST data of the National Oceanic and Atmospheric Administration (NOAA), European Centre for Medium-Range Weather Forecasts (ECMWF) and the Hadley Centre Sea Ice and Sea Surface Temperature data set (HadISST) and the reanalysis data of the National Center for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) for 33 years (from 1979 to 2011) were used to analyze the relationship between the Indian Ocean SST and the Tibetan Plateau's AHS in summer, using the approaches that include correlation analysis, and lead-lag analysis. Our results show that some certain strong oceanic SSTs affect the summer plateau heat, specially finding that the early spring SSTs of the Indian Ocean significantly affect the plateau's ability to serve as a heat source in summer. Moreover, the anomalous atmospheric circulation and transport of water vapor are related to the Plateau heat variation.

Preliminary evaluation of the uranium favorability in the Kaiparowits Plateau Region, Garfield and Kane Counties, Utah

International Nuclear Information System (INIS)

Dubyk, W.S.; Young, P.

1978-05-01

The basal sandstone of the Chinle Formation (Upper Triassic) and the Salt Wash Member of the Morrison Formation (Upper Jurassic) in the Kaiparowits Plateau, southcentral Utah, were evaluated in terms of uranium potential. Both surface and subsurface data were utilized. Favorability of the basal Chinle sandstone was based on (1) presence of intermediate-size sandstone-filled channels cut into the Moenkopi; (2) presence of carbonaceous material; (3) an adequate source of uranium; and (4) gamma-ray anomalies from test-hole logs. Favorability of the Salt Wash Member of the Morrison Formation was based on (1) sandstone-mudstone ratios that approach equality, and (2) presence of thick sandstone lenses, carbonaceous material, and halos of light-tan to brown limonite staining. Although the basal Chinle sandstone and the Salt Wash Member of the Morrison contain sizable uranium deposits throughout much of the Colorado Plateau, both units lack characteristics that are favorable for significant uranium deposits in the Kaiparowits Plateau

The application of INAA in a study of environment geochemistry on the Xizang (Tibet) Plateau, China

International Nuclear Information System (INIS)

Junliang Tian; Puling Liu; Yaqi Li

1993-01-01

INAA as a routine analysis method has been used in a study of environment geochemistry on the Xizang (Tibet) Plateau in China, and 34 elements in soil samples were determined by INAA with both short and long irradiations. Some primary results from the study, including mean element concentrations in Tibetian soil, patterns of element distribution in soils developed from main types of parent materials on the plateau are described. The results confirm the expectation that soil formed in such cold and dry environment on the the plateau retained the main geochemical characteristics of the parent materials. However, the results still imply the possible migration of some elements in different bio-climatic environments during the soil formation. The elements in the top soils, mainly the alkalis and alkaline earths, and also As, Br, etc., were enriched or depleted in varying degrees in proportion to their abundance in the parent materials. (author) 9 refs.; 4 tabs

Long-term strain accommodation in the eastern margin of the Tibetan Plateau: Insights from 3D thermo-kinematic modelling

Science.gov (United States)

Tian, Y.; Vermeesch, P.; Carter, A.; Zhang, P.

2017-12-01

The Cenozoic deformation of the Tibetan Plateau were dominated by the north-south collision between the Indian and Eurasian continents since Early Cenozoic time. Numerous lines of evidence suggest that the plateau has expanded outward after the collision, forming a diverging stress-regime from the collisional belt to plateau margins. When and how the expansional strain had propagated to the current plateau margins has been hotly debated. This work presents results of an on-going projects for understanding the long-term strain history along the Longmen Shan, the eastern margin of the Tibetan Plateau, where deformation is controlled by three parallel NW-dipping faults. From foreland (southeast) to hinterland (northwest), the main faults are the Guanxian-Anxian fault, Yingxiu-Beichuan fault and Wenchuan-Maowen fault. Exhumation pattern constrained by one-dimensional modelling made from a compilation of published and unpublished thermochronometry data shows a strong structural control, with highest amounts of exhumation in the hinterland region, a pattern that is characteristic of out-of-sequence reverse faulting (Tian et al., 2013, Tectonics, doi:10.1002/tect.20043; Tian et al., 2015, Geophys. Res. Lett., doi:10.1002/2014GL062383). Three-dimensional thermo-kinematic modelling of these data suggests that the Longmen Shan faults are listric in geometry, merging into a detachment at a depth of 20-30 km. The models require a marked decrease in slip-rate along the frontal Yingxiu-Beichuan in the late Miocene, whereas the slip-rate along the hinterland Wenchuan-Maowen fault remained relatively constant since early Miocene time. The long-term pattern of strain accommodation revealed by the three-dimensional thermo-kinematic modelling have important implications for distinguishing geodynamic models proposed for explaining the eastward growth of the Tibetan Plateau.

Impact of Cataract Surgery on Quality of Life in Plateau State, Nigeria

African Journals Online (AJOL)

Impact of Cataract Surgery on Quality of Life in Plateau State, Nigeria. ... The study instrument was the standardized Visual Function (VF-14) and Quality of ... Outcome Research Team (PORT), and designed to measure the impact of impaired ...

Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

Science.gov (United States)

Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

2016-01-01

Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

Conventional radiographic examination in the evaluation of sequelae after tibial plateau fractures

International Nuclear Information System (INIS)

Jensen, D.B.; Bjerg-Nielsen, A.; Laursen, N.; Glostrup Univ. Hospital

1988-01-01

Seventy patients with 72 conservatively treated tibial plateau fractures were re-examined after an average of 5 3/4 years. Among 55 fractured knees with a primary articular depression of 1-20 mm, the depression was still present radiographically in 47 knees. No correlation existed between the persistent radiographic depression and function of the knee. Moderate to severe osteoarthrosis was found in 10 knees; in five of these the osteoarthrosis was of clinical importance. More than 10 degrees of valgus/varus deformity was present in two knees. In two patients osteotomy had been performed to correct deformity. It is concluded that a persistent radiographic articular depression is of no clinical importance in tibial plateau fractures treated by conservative methods, which include early movement of the knee. The radiographic examination, however is, useful in the evaluation of valgus/varus deformity and osteoarthrosis. (orig.)

Water chemistry in the rives of the permafrost regions on the eastern Qinghai-Tibetan Plateau

Science.gov (United States)

Wu, X.; Ma, X.; Ye, L.; Liu, G.

2017-12-01

Qinghai-Tibetan is the largest middle-low latitude permafrost areas on the world. There are several large rivers in the plateau, and the changes of the water resources of these rivers are associated with the water resource security of more than 1.35 billion people. Due to the high gradients, these rivers have a tremendous amount of potential energy for electricity output. To promote economic and social development and provide clean energy, hydropower development has taken place on several rivers which originate on the Qinghai-Tibetan Plateau. Since dam construction affect the flow velocity, water temperature, sediments delivery as well as organic matter and nitrogen, it is important to investigate the river chemistry in the head rivers of the reservoirs. We examined the water physio-chemical characteristics in the rivers under the typical vegetation types in the eastern Qinghai-Tibetan Plateau, and further analyzed their relationship to vegetation. The results showed that the total suspended sediment in the rivers were higher within the catchment of alpine steppe, with the lowest dissolved organic carbon content. In contrast, the rivers within the meadow had the highest dissolved organic carbon and lowest total suspension sediment. The dissolved organic carbon significantly positively correlated with the proportions of the meadow and wet meadow in the catchment. The pH, turbidity, and SUVA254 and dissolved organic carbon also correlated with each other. The results suggest that the vegetation type strongly affect the water chemistry in the permafrost regions on the Qinghai-Tibetan Plateau.

Deep Vadose Zone-Applied Field Research Initiative Fiscal Year 2011 Annual Report

International Nuclear Information System (INIS)

Wellman, Dawn M.; Johnson, Timothy C.; Smith, Ronald M.; Truex, Michael J.; Matthews, Hope E.

2011-01-01

environment that leverages technology and scientific expertise from DOE, Pacific Northwest National Laboratory, CH2M HILL Plateau Remediation Company, and the broad scientific research community. As project manager for the DVZ-AFRI, I have had the privilege this past year to team with creative, talented members of the scientific community nationwide to develop effective long-term solutions to address deep vadose zone contamination. This report highlights how the DVZ-AFRI project team is delivering results by achieving significant programmatic accomplishments, and developing and field-testing transformational technologies to address the nation's most pressing groundwater and vadose zone contamination problems.

Response of greenhouse gas emissions from three types of wetland soils to simulated temperature change on the Qinghai-Tibetan Plateau

Science.gov (United States)

Liu, Yi; Liu, Guihua; Xiong, Ziqian; Liu, Wenzhi

2017-12-01

Wetlands emit a large quantity of greenhouse gases into the atmosphere and contribute significantly to global warming. The Qinghai-Tibetan Plateau, known as the ;Third Pole; of the earth, contains abundant and diverse wetlands. Due to increasing human-induced pressures such as reclamation, overgrazing and climate change, many plateau wetlands have been degraded or destroyed. Until now, the response of soil greenhouse gas emissions to extreme summer temperatures in the plateau wetlands remains unknown. In this study, we collected 36 soil samples from riverine, lacustrine and palustrine wetlands on the Qinghai-Tibetan Plateau. We compared the carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions from soils incubated aerobically at 7, 12, and 19 °C. The results showed that the emissions of CH4 and N2O but not CO2 were significantly affected by the simulated temperature change. The N2O emission rate was considerably higher in palustrine wetlands compared with lacustrine and riverine wetlands. However, the CO2 and CH4 emissions did not differ significantly among the three wetland types. The ratio of CO2 to CH4 production increased with increasing incubation temperatures. The global warming potential of greenhouse gases at 19 °C was approximately 1.18 and 2.12 times greater than that at 12 and 7 °C, respectively. Our findings suggest that temperature change has a strong effect on soil greenhouse gas emissions and global warming potential of wetlands on the Qinghai-Tibetan Plateau, especially palustrine wetlands. Therefore, targeted strategies should be developed to mitigate the potential impacts of climate warming on the plateau.

Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

International Nuclear Information System (INIS)

Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

1989-01-01

Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case where a flux tube of equipotential contours is not circular at the central cell

Role of pre-existing structures in controlling the Cenozoic tectonic evolution of the eastern Tibetan plateau: New insights from analogue experiments

Science.gov (United States)

Sun, Ming; Yin, An; Yan, Danping; Ren, Hongyu; Mu, Hongxu; Zhu, Lutao; Qiu, Liang

2018-06-01

Pre-existing weakness due to repeated tectonic, metamorphic, and magmatic events is a fundamental feature of the continental lithosphere on Earth. Because of this, continental deformation results from a combined effect of boundary conditions imposed by plate tectonic processes and heterogeneous and anisotropic mechanical strength inherited from protracted continental evolution. In this study, we assess how this interaction may have controlled the Cenozoic evolution of the eastern Tibetan plateau during the India-Asia collision. Specifically, we use analogue models to evaluate how the pre-Cenozoic structures may have controlled the location, orientation, and kinematics of the northwest-striking Xianshuihe and northeast-striking Longmen Shan fault zones, the two most dominant Cenozoic structures in eastern Tibet. Our best model indicates that the correct location, trend, and kinematics of the two fault systems can only be generated and maintained if the following conditions are met: (1) the northern part of the Songpan-Ganzi terrane in eastern Tibet has a strong basement whereas its southern part has a weak basement, (2) the northern strong basement consists of two pieces bounded by a crustal-scale weak zone that is expressed by the Triassic development of a northwest-trending antiform exposing middle and lower crustal rocks, and (3) the region was under persistent northeast-southwest compression since ∼35 Ma. Our model makes correct prediction on the sequence of deformation in eastern Tibet; the Longmen Shan right-slip transpressional zone was initiated first as an instantaneous response to the northeast-southwest compression, which is followed by the formation of the Xianshuihe fault about a half way after the exertion of northeast-southwest shortening in the model. The success of our model highlights the importance of pre-existing weakness, a key factor that has been largely neglected in the current geodynamic models of continental deformation.

Magnetostratigraphy of the Dali Basin in Yunnan and implications for late Neogene rotation of the southeast margin of the Tibetan Plateau

NARCIS (Netherlands)

Li, Shihu; Deng, Chenglong; Yao, Haitao; Huang, Sheng; Liu, Chengying; He, Huaiyu; Pan, Yongxin; Zhu, Rixiang

[1] The rotation pattern and fault activity in the southeast margin of the Tibetan Plateau (SEMTP) provide meaningful constraints on the geodynamic evolution of the plateau. However, the lack of Cenozoic paleomagnetic studies and accurate age constraints on Neogene sediments prevents a better

Characteristics and sources of chromophoric dissolved organic matter in lakes of the Yungui Plateau, China, differing in trophic state and altitude

NARCIS (Netherlands)

Zhang, Y.; Zhang, E.; Yin, Y.; Van Dijk, M.A.; Feng, L.; Shi, Z.; Liu, M.; Qina, B.

2010-01-01

The high-mountain lakes on the Yungui Plateau in China are exposed to high-intensity ultraviolet radiation, and contain low concentrations of chromophoric dissolved organic matter (CDOM). We determined CDOM absorption, fluorescence, composition, and source in 38 lakes on the Yungui Plateau at

Evidence for northeastern Tibetan Plateau uplift between 25 and 20Ma in the sedimentary archive of the Xining Basin, Northwestern China

NARCIS (Netherlands)

Xiao, G.; Guo, Z.; Dupont-Nivet, G.; Lu, H.; Wu, N.; Ge, J.; Hao, Q.; Peng, S.; Li, F.; Abels, H.A.; Zhang, K.

2011-01-01

The growth history of the Tibetan Plateau provides a valuable natural laboratory to understand tectonic processes of the India–Asia collision and their impact on and interactions with Asian and global climate change. However, both Tibetan Plateau growth and Asian paleoenvironments are generally

Slow growth of the Rayleigh-Plateau instability in aqueous two phase systems

NARCIS (Netherlands)

Geschiere, S.D.; Ziemecka, I.; Van Steijn, V.; Koper, G.J.M.; Van Esch, J.H.; Kreutzer, M.T.

2012-01-01

This paper studies the Rayleigh-Plateau instability for co-flowing immiscible aqueous polymer solutions in a microfluidic channel. Careful vibration-free experiments with controlled actuation of the flow allowed direct measurement of the growth rate of this instability. Experiments for the

Reassessment of soil erosion on the Chinese loess plateau: were rates overestimated?

Science.gov (United States)

Zhao, Jianlin; Govers, Gerard

2014-05-01

Several studies have estimated regional soil erosion rates (rill and interrill erosion) on the Chinese loess plateau using an erosion model such as the RUSLE (e.g. Fu et al., 2011; Sun et al., 2013). However, the question may be asked whether such estimates are realistic: studies have shown that the use of models for large areas may lead to significant overestimations (Quinton et al., 2010). In this study, soil erosion rates on the Chinese loess plateau were reevaluated by using field measured soil erosion data from erosion plots (216 plots and 1380 plot years) in combination with a careful extrapolation procedure. Data analysis showed that the relationship between slope and erosion rate on arable land could be well described by erosion-slope relationships reported in the literature (Nearing, 1997). The increase of average erosion rate with slope length was clearly degressive, as could be expected from earlier research. However, for plots with permanent vegetation (grassland, shrub, forest) no relationship was found between erosion rates and slope gradient and/or slope length. This is important, as it implies that spatial variations of erosion on permanently vegetated areas cannot be modeled using topographical functions derived from observations on arable land. Application of relationships developed for arable land will lead to a significant overestimation of soil erosion rates. Based on our analysis we estimate the total soil erosion rate in the Chinese Loess plateau averages ca. 6.78 t ha-1 yr-1 for the whole loess plateau, resulting in a total sediment mobilisation of ca. 0.38 Gt yr-1. Erosion rates on arable land average ca. 15.10 t ha-1 yr-1. These estimates are 2 to 3 times lower than previously published estimates. The main reason why previous estimates are likely to be too high is that the values of (R)USLE parameters such as K, P and LS factor were overestimated. Overestimations of the K factor are due to the reliance of nomograph calculations, resulting

Lower crustal relaxation beneath the Tibetan Plateau and Qaidam Basin following the 2001 Kokoxili earthquake

Science.gov (United States)

Ryder, I.; Burgmann, R.; Pollitz, F.

2011-01-01

In 2001 November a magnitude 7.8 earthquake ruptured a 400 km long portion of the Kunlun fault, northeastern Tibet. In this study, we analyse over five years of post-seismic geodetic data and interpret the observed surface deformation in terms of stress relaxation in the thick Tibetan lower crust. We model GPS time-series (first year) and InSAR line of sight measurements (years two to five) and infer that the most likely mechanism of post-seismic stress relaxation is time-dependent distributed creep of viscoelastic material in the lower crust. Since a single relaxation time is not sufficient to model the observed deformation, viscous flow is modelled by a lower crustal Burgers rheology, which has two material relaxation times. The optimum model has a transient viscosity 9 ?? 1017 Pa s, steady-state viscosity 1 ?? 1019 Pa s and a ratio of long term to Maxwell shear modulus of 2:3. This model gives a good fit to GPS stations south of the Kunlun Fault, while displacements at stations north of the fault are over-predicted. We attribute this asymmetry in the GPS residual to lateral heterogeneity in rheological structure across the southern margin of the Qaidam Basin, with thinner crust/higher viscosities beneath the basin than beneath the Tibetan Plateau. Deep afterslip localized in a shear zone beneath the fault rupture gives a reasonable match to the observed InSAR data, but the slip model does not fit the earlier GPS data well. We conclude that while some localized afterslip likely occurred during the early post-seismic phase, the bulk of the observed deformation signal is due to viscous flow in the lower crust. To investigate regional variability in rheological structure, we also analyse post-seismic displacements following the 1997 Manyi earthquake that occurred 250 km west of the Kokoxili rupture. We find that viscoelastic properties are the same as for the Kokoxili area except for the transient viscosity, which is 5 ?? 1017 Pa s. The viscosities estimated for the

[Tibial plateau fractures in winter sports. Current treatment options].

Science.gov (United States)

Zimmermann, V

2014-01-01

Tibial plateau fractures overall and especially in winter sports are rare. However, the incidence in recent years is increasing. In a retrospective study from 2009-2012, we found 52 injuries affiliated with winter sports. Noticeable was the high rate of severe injury patterns. In 20 of the 52 cases, there were complete articular or bicondylar fractures (38 %). In 25 cases (48 %), fragment dislocation corresponding to the Moore classification was observed. The operative algorithm was based on the initial soft tissue damage and the type of fracture. A two or more stage procedure with first line soft tissue management and temporary external fixation stabilization was performed 12 times. The final internal osteosynthesis was based on the morphology of the fracture, i.e., direct exposition and stabilization of relevant fracture patterns. In 24 cases (46 %), there was a need for two (or more) approaches. In the anterior aspect of the tibial head, customary implants were used; posterior pathologies were stabilized with low-dimension implants. Summarizing with regard to the literature, there is a more discriminating view of tibial plateau fractures, regarding all relevant fracture patterns. Thus, different options in operative access and choice of implants can be made.

A CLINICAL STUDY ON SURGICAL MANAGEMENT OF TIBIAL PLATEAU FRACTURES - FUNCTIONAL AND RADIOLOGICAL EVALUATION

Directory of Open Access Journals (Sweden)

Bhavani

2015-10-01

Full Text Available BACKGROUND: Tremendous advance in mechanization and fastness of travel have been accompanied by steep increase in number and severity of fractures and those of tibial plateau are no exception. Knee being one of the major weight bearing joints of the body, fractures around it will be of paramount importance. AIM OF STUDY: This study is to analyze the functional outcome of CRIF or ORIF with or without bone grafting in tibial plateau fractures in adults. MATERIALS AND METHODS: 30 cases of tibial plateau fractures treated by various modalities were studied from 1 - 8 - 2012 to 31 - 1 - 2014 at our institution and followed for a minimum of 6 months. Fractures were evaluated using Modified Rasmussen’s Clinical, Radiological grading system. RESULTS : The selected patients were evaluated thoroughly and after the relevant investigations, were taken for surgery. The fractures were classified as per the SCHATZKER’S types and operated accordingly with CRIF with Percutaneous cannulated cancellous screws, ORIF with buttress plate/LCP with or without bone grafting. Immobilization of fractures continued for 3 weeks by POP slab. Early range of motion was then started. Weight bearing up to 6 - 8 weeks was not allowed. The full weight bearing deferred until 12 weeks or complete fracture union . The knee range of motion was excellent to very good, gait and weight bearing after complete union was satisfactory, knee stiffness in 3 cases , wound dehiscence and infection in 1 case and non - union in none of our cases was noted. CONCLUSION: Functional outcome is better in operatively treated tibial plateau fractures in adults, because it gives excellent anatomical reduction and rigid fixation to restore articular congruity and early motion thereby preventing knee stiffness.

Modern limnology of two lakes in the Tibetan Plateau - evidence from in-situ monitoring

Science.gov (United States)

Wang, M.; Li, X.; Lei, L.; He, Y.; Hou, J.

2013-12-01

The mechanisms of climate change in the Tibetan Plateau, known as the Third Pole, receive more and more attention due to its unique geographic location and the influence of multiple climate systems. Among the paleoclimate archives, widespread lakes provide abundant information on past climate changes and have been investigated for decades. Though many high-quality paleolimnological records have been reported in the Tibetan Plateau, little is known about the modern limnological processes in most Tibetan lakes as most lakes are difficult to access and not ready for long-term monitoring. We have installed a series of temperature data logger at different water levels in two Tibetan lakes, Bangong Co and Dagze Co in July 2012 to monitor hourly variability of temperature profile. Bangong Co (33.5°N, 79.8°E, 4245 m asl) is a freshwater lake (salinity ~0.5 g/L) in the westernmost Tibetan Plateau, receiving melt water from mountain glaciers in the basin. Dagze Co (31.9°N, 87.5°E, 4470 m asl) is saline lake (salinity ~15 g/L) in the central Tibetan Plateau, mostly fed by precipitation. In combination with the climate data in the nearby weather stations, we wish to understand the modern limnological processes in the two lakes and their potential effect on the lake biology, sedimentation, and sedimentary biomarkers. Based on the data collected for the first calendar year (Jul 2012 ~ Aug 2013), we anticipate to understand: 1) the influence of climate on the hydrological processes in high elevation lakes; 2) the difference in the metalimnion in meltwater-fed lake (Bangong Co) and precipitation-fed lake (Dagze Co) and their potential effect on the lake biology; 3) the difference in the spring turnover and fall turnover and the effect of meltwater and salinity.

Sports activity after surgical treatment of intra-articular tibial plateau fractures in skiers.

Science.gov (United States)

Loibl, Markus; Bäumlein, Martin; Massen, Felix; Gueorguiev, Boyko; Glaab, Richard; Perren, Thomas; Rillmann, Paavo; Ryf, Christian; Naal, Florian D

2013-06-01

Tibial plateau fractures occur frequently while participating in winter sports, but there is no information on whether skiers can resume sports and recreational activities after internal fixation of these fractures. Skiers can resume low-impact sports activity after internal fixation of tibial plateau fractures. Case series; Level of evidence, 4. A total of 103 patients were surveyed by postal questionnaires to determine their sports activities at a mean of 7.8 ± 1.8 years after internal fixation of intra-articular tibial plateau fractures. The survey also included the Lysholm score, the Tegner activity scale, and a visual analog scale (VAS) for pain. At the time of the survey, 88% of the patients were engaged in sports activities (rate of return to sports, 88%), and 53% continued to participate in downhill skiing. The median number of different activities declined from 5 (range, 1-17) preoperatively to 4 (range, 0-11) postoperatively (P Sports frequency and duration per week did not change: 3 (range, 1-7) preoperatively versus 3 (range, 0-7) postoperatively (P = .275) and 4 hours (range, 1-16 hours) preoperatively versus 3.5 hours (range, 0-15 hours) postoperatively (P = .217), respectively. Median values of all outcome scores declined: Lysholm score, 100 (range, 85-100) preoperatively versus 94.5 (range, 37-100) postoperatively (P sports at the time of follow-up compared with the ability before the accident was rated as "similar" by 57 patients (62.0%) and as "worse" by 35 patients (38.0%). The more severe fracture types, B3 and C3 according to the AO classification system, were associated with poorer outcomes related to return to sports and functional scores. A large percentage of skiers with surgically treated intra-articular tibial plateau fractures cannot continue to participate in downhill skiing; however, the majority could resume an active lifestyle for several years after the trauma. Fracture type seems to be an important factor influencing physical

Evaluation of ECMWF's soil moisture analyses using observations on the Tibetan Plateau

NARCIS (Netherlands)

Su, Zhongbo; de Rosnay, P.; Wen, J.; Wang, Lichun; Zeng, Yijian

2013-01-01

An analysis is carried out for two hydrologically contrasting but thermodynamically similar areas on the Tibetan Plateau, to evaluate soil moisture analysis based on the European Centre for Medium‐Range Weather Forecasts (ECMWF) previous optimum interpolation scheme and the current point‐wise

Regional circulation around Heard and McDonald Islands and through the Fawn Trough, central Kerguelen Plateau

Science.gov (United States)

van Wijk, Esmee M.; Rintoul, Stephen R.; Ronai, Belinda M.; Williams, Guy D.

2010-05-01

The fine-scale circulation around the Heard and McDonald Islands and through the Fawn Trough, Kerguelen Plateau, is described using data from three high-resolution CTD sections, Argo floats and satellite maps of chlorophyll a, sea surface temperature (SST) and absolute sea surface height (SSH). We confirm that the Polar Front (PF) is split into two branches over the Kerguelen Plateau, with the NPF crossing the north-eastern limits of our survey carrying 25 Sv to the southeast. The SPF was associated with a strong eastward-flowing jet carrying 12 Sv of baroclinic transport through the deepest part of Fawn Trough (relative to the bottom). As the section was terminated midway through the trough this estimate is very likely to be a lower bound for the total transport. We demonstrate that the SPF contributes to the Fawn Trough Current identified by previous studies. After exiting the Fawn Trough, the SPF crossed Chun Spur and continued as a strong north-westward flowing jet along the eastern flank of the Kerguelen Plateau before turning offshore between 50°S and 51.5°S. Measured bottom water temperatures suggest a deep water connection between the northern and southern parts of the eastern Kerguelen Plateau indicating that the deep western boundary current continues at least as far north as 50.5°S. Analysis of satellite altimetry derived SSH streamlines demonstrates a southward shift of both the northern and southern branches of the Polar Front from 1994 to 2004. In the direct vicinity of the Heard and McDonald islands, cool waters of southern origin flow along the Heard Island slope and through the Eastern Trough bringing cold Winter Water (WW) onto the plateau. Complex topography funnels flow through canyons, deepens the mixed layer and increases productivity, resulting in this area being the preferred foraging region for a number of satellite-tracked land-based predators.

Ethnobotanical Study of Medicinal Plants Used for the Treatment of Malaria in the Plateau Region, Togo.

Science.gov (United States)

Agbodeka, Kodjovi; Gbekley, Holaly E; Karou, Simplice D; Anani, Kokou; Agbonon, Amegnona; Tchacondo, Tchadjobo; Batawila, Komlan; Simpore, Jacques; Gbeassor, Messanvi

2016-03-01

In Togo, malaria constitutes a major public health problem but, until now, the population still mostly relies on herbal medicine for healing. This study aimed to document medicinal plants used for malaria therapy in the Plateau region of the country. Semi-structured questionnaire interviews were used to gather ethnobotanical and sociodemographic data from traditional healers of the study area. A total of 61 plants species belonging to 33 families were found to be in use for malaria therapy in the Plateau region. Caesalpiniaceae were the most represented family with 7 species, followed by Euphorbiaceae and Poaceae with 4 species each. According to the relative frequency of citation (RFC), Newbouldia laevis Seem. (RFC =0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC =0.48), Acanthospermum hispidum DC. (RFC =0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC =0.40) were the most cited in the treatment of malaria in the traditional medicine in the Plateau region. The parts of plants used could either be the barks, roots, leaves, or whole plants. The recipes also could be a combination of various species of plants or plant parts. This study highlights the potential sources for the development of new antimalarial drugs from indigenous medicinal plants found in the Plateau region of Togo. Such results could be a starting point for in vitro antimalarial screenings. 61 plants species from 33 families are use for malaria therapy in the Plateau region of TogoThe main families are Caesalpiniaceae Euphorbiaceae and PoaceaeThe most used species are Newbouldia laevis Seem. (RFC = 0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC = 0.48), Acanthospermum hispidum DC. (RFC = 0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC = 0.40) Abbreviations Used: RFC: Relative frequency of citation, FC: Frequency of citation, Dec: Decoction, Orl: Oral route, Mac: Maceration, Jui: Juice, Inf: Infusion, Sau: Sauce, Kne: Kneading, Le: Leaves, Rt: Roots, Wp: Whole plant

Observational Evidence of EHP Effects on the Melting of Snowpack over the Tibetan Plateau

Science.gov (United States)

Kim, Maeng-Ki; Lau, William K. M.; Kim, Kyu-Myong; Lee, Woo-Seop

2012-01-01

Observational evidences are presented showing that the Indo-Gangetic Plain (IGP) regions, bounded by the high altitude Himalayan mountains, are subject to heavy loading of absorbing aerosols, i.e., black carbon and dust, which can lead to widespread enhancement warming over the Tibetan Plateau and accelerated snowmelt in the western Tibetan Plateau (WTP) and Himalayas. The two pre-monsoon seasons of 2004 and 2005 were strikingly contrasting in terms of the aerosol loading over IGP. The warming of the TP in 2004 relative to 2005 was widespread, covering most of the WTP and Himalayas. This warming is closely linked to patterns of the snow melt. Consistent with the Elevated Heat Pump hypothesis, we find that increased loading of absorbing aerosols over IGP in the pre-monsoon season is associated with increased heating of the upper troposphere by dynamical feedback induced by aerosol heating, and enhances the rate of snowmelt over Himalayas and the WTP in April-May. Composite analysis with more contrasting years also shows that the heating of the troposphere by elevated dust and black carbon aerosols in the boreal spring can lead to widespread enhanced land-atmosphere warming, and accelerated snow melt in the Himalayas and Tibetan Plateau.

Giant magnetoresistance, three-dimensional Fermi surface and origin of resistivity plateau in YSb semimetal.

Science.gov (United States)

Pavlosiuk, Orest; Swatek, Przemysław; Wiśniewski, Piotr

2016-12-09

Very strong magnetoresistance and a resistivity plateau impeding low temperature divergence due to insulating bulk are hallmarks of topological insulators and are also present in topological semimetals where the plateau is induced by magnetic field, when time-reversal symmetry (protecting surface states in topological insulators) is broken. Similar features were observed in a simple rock-salt-structure LaSb, leading to a suggestion of the possible non-trivial topology of 2D states in this compound. We show that its sister compound YSb is also characterized by giant magnetoresistance exceeding one thousand percent and low-temperature plateau of resistivity. We thus performed in-depth analysis of YSb Fermi surface by band calculations, magnetoresistance, and Shubnikov-de Haas effect measurements, which reveals only three-dimensional Fermi sheets. Kohler scaling applied to magnetoresistance data accounts very well for its low-temperature upturn behavior. The field-angle-dependent magnetoresistance demonstrates a 3D-scaling yielding effective mass anisotropy perfectly agreeing with electronic structure and quantum oscillations analysis, thus providing further support for 3D-Fermi surface scenario of magnetotransport, without necessity of invoking topologically non-trivial 2D states. We discuss data implying that analogous field-induced properties of LaSb can also be well understood in the framework of 3D multiband model.

Old-field plant succession on the Pajarito Plateau

International Nuclear Information System (INIS)

Foxx, T.; Mullen, M.; Salisbury, M.; Tierney, G.

1997-10-01

Eight fallow historic fields of the ponderosa pine and pinon-juniper cover types were surveyed to determine species composition and distribution. The purpose of the study was to understand plant succession on old fields as related to mechanically manipulated sites such as material disposal areas (MDAs). Additionally, the authors wanted a listing of species on disturbed lands of the Pajarito Plateau to aide in the reclamation planning of MDAs using native species. They also wanted to determine if any species could be used as an indicator of disturbance. The eight historic fields were all within Los Alamos County, New Mexico, and had been abandoned in 1943. Two sites were within the boundaries of Los Alamos National Laboratory and were studied both in 1982 and 1993. The study provides a description of each of the field sites, historic information about the homesteads from patent applications, a photographic record of some of the sites, and a listing of species found within each field. The study showed that there were 78 different plant species found on disturbed sites. Of these 78 species, 23 were found to be dominant on one or more of the MDAs or old fields. Although, the disturbance history of each site is imperfectly known, the study does provide an indication of successional processes within disturbed sites of the Pajarito Plateau. Additionally, it provides a listing of species that will invade disturbed sites, species that may be used in site reclamation

Old-field plant succession on the Pajarito Plateau

Energy Technology Data Exchange (ETDEWEB)

Foxx, T.; Mullen, M.; Salisbury, M. [Los Alamos National Lab., NM (United States); Tierney, G. [Tierney (Gail), Santa Fe, NM (United States)

1997-10-01

Eight fallow historic fields of the ponderosa pine and pinon-juniper cover types were surveyed to determine species composition and distribution. The purpose of the study was to understand plant succession on old fields as related to mechanically manipulated sites such as material disposal areas (MDAs). Additionally, the authors wanted a listing of species on disturbed lands of the Pajarito Plateau to aide in the reclamation planning of MDAs using native species. They also wanted to determine if any species could be used as an indicator of disturbance. The eight historic fields were all within Los Alamos County, New Mexico, and had been abandoned in 1943. Two sites were within the boundaries of Los Alamos National Laboratory and were studied both in 1982 and 1993. The study provides a description of each of the field sites, historic information about the homesteads from patent applications, a photographic record of some of the sites, and a listing of species found within each field. The study showed that there were 78 different plant species found on disturbed sites. Of these 78 species, 23 were found to be dominant on one or more of the MDAs or old fields. Although, the disturbance history of each site is imperfectly known, the study does provide an indication of successional processes within disturbed sites of the Pajarito Plateau. Additionally, it provides a listing of species that will invade disturbed sites, species that may be used in site reclamation.

Influence of environmental factors on spectral characteristics of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China

Science.gov (United States)

Wen, Z. D.; Song, K. S.; Zhao, Y.; Du, J.; Ma, J. H.

2016-02-01

Spectral characteristics of chromophoric dissolved organic matter (CDOM) were examined in conjunction with environmental factors in the waters of rivers and terminal lakes within the Hulun Buir plateau, northeast China. Dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorous (TP) were significantly higher in terminal lakes than rivers waters (p CDOM absorption in river waters was significantly lower than terminal lakes. Analysis of the ratio of absorption at 250 to 365 nm (E250 : 365), specific ultraviolet (UV) absorbance (SUVA254), and the spectral slope ratio (Sr) indicated that CDOM in river waters had higher aromaticity, molecular weight, and vascular plant contribution than in terminal lakes. Furthermore, results showed that DOC concentration, CDOM light absorption, and the proportion of autochthonous sources of CDOM in plateau waters were all higher than in other freshwater rivers reported in the literature. The strong evapoconcentration, intense ultraviolet irradiance, and landscape features of the Hulun Buir plateau may be responsible for the above phenomenon. Redundancy analysis (RDA) indicated that the environmental variables total suspended matter (TSM), TN, and electrical conductivity (EC) had a strong correlation with light absorption characteristics, followed by total dissolved solid (TDS) and chlorophyll a. In most sampling locations, CDOM was the dominant non-water light-absorbing substance. Light absorption by non-algal particles often exceeded that by phytoplankton in the plateau waters. Study of these optical-physicochemical correlations is helpful in the evaluation of the potential influence of water quality factors on non-water light absorption in cold plateau water environments. The construction of a correlation between DOC concentration and water quality factors may help contribute to regional estimates of carbon sources and fate for catchment carbon budget assessments.

Consuming the savings: Water conservation in a vegetation barrier system at the Central Plateau in Burkina Faso

OpenAIRE

Spaan, W.

2003-01-01

The vast majority of land users at the Central Plateau of Burkina Faso make a living by farming small plots, where mainly staple crops are produced for subsistence use. Both area interventions and line interventions comprising indigenous techniques as well as introduced techniques can be encountered at the Central Plateau and have proved to be effective. There is a preference for semi-permeable line measures that slow down runoff and prevent water logging in wet periods.In order to ascertain ...

Vadose Zone Infiltration Rates from Sr isotope Measurements

Science.gov (United States)

Maher, K.; Maher, K.; DePaolo, D. J.; DePaolo, D. J.; Conrad, M.

2001-12-01

Predicting infiltration rates and recharge through the vadose zone in arid regions is difficult and hence developing methods for the measurement of infiltration rates is important. We have been investigating the use of Sr isotope measurements for determining infiltration at the 200 Area plateau on the Hanford reservation in central Washington. In this context, infiltration affects the transport of contaminants to the water table as well as recharge of the groundwater system. Using Sr isotopes for this purpose requires drill core and water samples from the vadose zone, although leaches of the cores can substitute for water samples. Complementary information, including some constraints on regional recharge, can also be obtained using water samples from groundwater monitoring wells. The VZ method is based on the fact that the Sr isotope ratio of soil water just below the surface is often set by dissolution of aeolian material including carbonate, and this ratio is different from the average value in the deeper underlying vadose zone rock matrix. As water infiltrates, the Sr isotopic composition of the water changes toward the rock values as a result of Sr released from the rocks by weathering reactions. The rate of change with depth of the Sr isotope ratio of the vadose zone water is a function ultimately of q/R; the ratio of the infiltration flux (q) to the bulk rock weathering rate (R). Where it is possible to evaluate R, q can be estimated. As data accumulate it may be possible to improve the calibration of the method. At Hanford the vadose zone rock material is mostly unconsolidated sand, silt, and gravel of broadly granitic composition, which constitute the Hanford and Ringold formations. Annual precipitation is about 160 mm/yr. Drilling and coring of a ca. 70m hole to the water table in 1999 as part of the Hanford groundwater monitoring program, in a relatively undisturbed area of the site, allowed us to generate a unique Sr isotope data set. The Sr isotope

Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

International Nuclear Information System (INIS)

Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

1988-07-01

Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case that a magnetic flux tube of an equipotential contours is not circular at the central cell. (author)

Ornithological monitoring of the wind farms of the Garrigue high plateau (Aude); Suivi ornithologique des parcs eoliens du Plateau de Garrigue Haute (Aude)

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This document presents the monitoring of the premarital migration 2001 in the wind farm of Corbieres-Maritime on the Garrigue Haute plateau. It aims to study the wind turbines impacts and risks on the migration. In spite of a weak mortality, the number of observed modifications in the birds habits at the approach of the wind turbines confirms the necessity of taking into account the migration phenomena in the wind farms projects. (A.L.B.)

Desertification in 1957-2015 Estimated from Vegetation Coverage and Climate Conditions on the Tibetan Plateau

Science.gov (United States)

Cuo, L.

2017-12-01

Desert is an area that receives less than 25 cm precipitation in cold climate or 50 cm precipitation in hot climate (Miller, 1961). Others defined true desert as a region having no recorded precipitation in 12 consecutive months (McGinnies et al., 1968). According to Koppen-Gieger climate classification system, if mean annual precipitation is less than 50% of the value A calculated by mean annual temperature times 20 plus 280 if 70% or more precipitation falls in April-September, the region has desert climate; if the mean annual precipitation is within 50%-100% of the value A, the region has semi-arid or steppe climate. On the Tibetan Plateau, the above definitions will result in no desert at all or the majority of the region falling into the category of desert which is not consistent with reality based on field exploration. In this study, the fractional vegetation coverage (FPC), precipitation, soil moisture and extreme wind days are used as indices to define areas of various degrees of desertification which produces much more realistic distribution of desert areas on the plateau. The Lund-Potsdam-Jena Dynamic Vegetation model (LPJ) is used to simulate vegetation growth, succession and vegetation properties such as FPC and soil moisture on the Tibetan Plateau. Gridded daily climate data are generated to drive the model and to analyze the status and changes of various deserts including light desert, medium desert, severe desert, extremely severe desert and desert proned area. The study will reveal the status and changes of possible driving factors of desertification, as well as various kinds of desert on the Tibetan Plateau during 1957-2015.

Historical reconstruction of mercury pollution across the Tibetan Plateau using lake sediments.

Science.gov (United States)

Yang, Handong; Battarbee, Richard W; Turner, Simon D; Rose, Neil L; Derwent, Richard G; Wu, Guangjian; Yang, Ruiqiang

2010-04-15

The Tibetan Plateau is described as the "Roof of the World" averaging over 4000 m above sea level; it is remote, isolated, and presumed to be a pristine region. In order to study the history of atmospheric mercury (Hg) pollution and its spatial variation across the Plateau, lakes were chosen from three areas forming a north to south transect. Sediment cores were taken from three sites in each area and dated using the radionuclides 210Pb and 137Cs. Analysis of the cores yielded the first comprehensive Hg reconstructions for the Plateau, showing clear Hg pollution at all sites. The first indication of Hg pollution is much earlier than the onset of the industrial revolution in Europe, but the most significant pollution increase is from the 1970s, followed by a further marked increase from the 1990s. The mean post-2000 atmospheric pollution Hg accumulation rates for the sampling sites were estimated at between 5.1 and 7.9 microg m(-2) yr(-1). The increase in Hg pollution over the last few decades is synchronous with the recent economic development in Asia (especially China and India), and pollution Hg levels continue to increase. Furthermore, contemporary sediment Hg accumulation rate data are in broad agreement with Hg deposition values derived from global models that attribute pollution to sources mainly within southeast Asia. As most of the sites are exceptionally remote and situated above the atmospheric boundary layer, these results underline the need to understand the local Hg cycle in both regional and global context.

Snow surface microbiome on the High Antarctic Plateau (DOME C).

Science.gov (United States)

Michaud, Luigi; Lo Giudice, Angelina; Mysara, Mohamed; Monsieurs, Pieter; Raffa, Carmela; Leys, Natalie; Amalfitano, Stefano; Van Houdt, Rob

2014-01-01

The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH), and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<10(3) cells/ml of snowmelt), concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae), which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae) and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau.

Snow surface microbiome on the High Antarctic Plateau (DOME C.

Directory of Open Access Journals (Sweden)

Luigi Michaud

Full Text Available The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH, and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<10(3 cells/ml of snowmelt, concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae, which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau.

Spontaneous osteonecrosis of the knee associated with tibial plateau and femoral condyle insufficiency stress fracture

Energy Technology Data Exchange (ETDEWEB)

Narvaez, J.A.; Narvaez, J.; Lama, E.De; Sanchez, A. [Department of Magnetic Resonance Imaging, IDI Hospital Duran i Reynals, Ciutat Sanitaria i Universitaria de Bellvitge, Gran Via s/n, 08907, L' Hospitalet de Llobregat (Barcelona) (Spain)

2003-08-01

The purpose of this article is to describe the association between spontaneous osteonecrosis and insufficiency stress fractures of the knee. To determine whether insufficiency stress fracture is associated with spontaneous osteonecrosis of the knee, we retrospectively reviewed the medical charts and imaging studies of all patients with spontaneous osteonecrosis of the knee, studied by MR imaging, seen in a tertiary hospital over an 8-year period. Four women (age range 66-84 years) presented spontaneous osteonecrosis of the knee associated with insufficiency stress fracture of the medial tibial plateau. One of these patients also presented a concomitant insufficiency stress fracture of the medial femoral condyle. Radiographs were diagnostic of spontaneous osteonecrosis of the medial femoral condyle in three cases, and insufficiency stress fracture of the medial tibial plateau was detected in one case. Magnetic resonance imaging allows the diagnosis of both conditions in all four cases. Spontaneous osteonecrosis of the knee may be associated with insufficiency stress fracture of the medial femoral condyle and the medial tibial plateau. This association provides additional arguments in favor of the traumatic etiology of spontaneous osteonecrosis of knee. (orig.)

Seasonal variations of stable isotope in precipitation and moisture transport at Yushu,eastern Tibetan Plateau

Institute of Scientific and Technical Information of China (English)

2008-01-01

Precipitation δ 18O at Yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at Yushu is apparently different from either that of the southwest monsoon region to the south or that of the inland region to the north. This different seasonal pattern probably reflects the shift of different moisture sources. In this paper, we present the spatial comparison of the seasonal patterns of precipitation δ 18O, and calculate the moisture transport flux by using the NCAR/NCEP reanalysis data. This allows us to discuss the relation between moisture transport flux and precipitation δ 18O. This study shows that both the southwest monsoon from south and inland air mass transport from north affected the seasonal precipitation δ 18O at Yushu, eastern Tibetan Plateau. Southwest monsoon brings the main part of the moisture, but southwest transport flux is weaker than in the southern part of the Tibetan Plateau. However, contribution of the inland moisture from north or local evaporation moisture is enhanced. The combined effect is the strong fluctuation of summer precipitation δ 18O at Yushu and comparatively poor seasonality.

Spontaneous osteonecrosis of the knee associated with tibial plateau and femoral condyle insufficiency stress fracture

International Nuclear Information System (INIS)

Narvaez, J.A.; Narvaez, J.; Lama, E.De; Sanchez, A.

2003-01-01

The purpose of this article is to describe the association between spontaneous osteonecrosis and insufficiency stress fractures of the knee. To determine whether insufficiency stress fracture is associated with spontaneous osteonecrosis of the knee, we retrospectively reviewed the medical charts and imaging studies of all patients with spontaneous osteonecrosis of the knee, studied by MR imaging, seen in a tertiary hospital over an 8-year period. Four women (age range 66-84 years) presented spontaneous osteonecrosis of the knee associated with insufficiency stress fracture of the medial tibial plateau. One of these patients also presented a concomitant insufficiency stress fracture of the medial femoral condyle. Radiographs were diagnostic of spontaneous osteonecrosis of the medial femoral condyle in three cases, and insufficiency stress fracture of the medial tibial plateau was detected in one case. Magnetic resonance imaging allows the diagnosis of both conditions in all four cases. Spontaneous osteonecrosis of the knee may be associated with insufficiency stress fracture of the medial femoral condyle and the medial tibial plateau. This association provides additional arguments in favor of the traumatic etiology of spontaneous osteonecrosis of knee. (orig.)

Deep physical structure and geotectonic implications of the eastern margin of the Qinghai–Tibet Plateau

Directory of Open Access Journals (Sweden)

Jun Li

2016-10-01

Full Text Available The eastern margin of the Qinghai–Tibet Plateau (QTP is the focus of studies on eastward lateral extrusion of the latter’s crustal material. This study aims to explore the structural response of the QTP’s eastern crust–mantle to the extrusion, and the basis for the latter’s geological structure. Data on long-period magnetotelluric sounding of cross-tectonic units and Bouguer gravity were used to determine the physical structure of the crust–mantle at the plateau’s eastern margin. The findings are as follows: (i the apparent density structure indicates extensive presence of a low-density material in the middle–lower crusts of the Songpan and Sichuan–Yunnan blocks at the QTP’s eastern margin. On the other hand, the Yangtze cratonic block (Sichuan Basin contains a material with a significantly higher density. To the west of the Longmenshan–Panxi tectonic zones, and along the lower crust at 40–50 km depth, is an obvious low-density zone aligned in a northeast–southwest orientation; (ii the electrical structural model spanning Songpan block–Longmenshan tectonic zone–Yangtze block reveals three distinct electrical structural units along the cross-section bounded by the Longmenshan tectonic zone. The first is the Songpan block, which has high and low resistivity at the shallow layer and middle–lower crusts, respectively. Next is the Yangtze craton, which has low and relatively higher resistivity at the shallow layer and middle–lower crusts, respectively. Third is the Longmenshan transitional tectonic zone, whose shallow layer and deep structure are characterized by an electrical structure with a thrust nappe towards the east, and a high-conductivity material extending to the lithospheric mantle, respectively; (iii the apparent density and electrical structures indicate that the Panxi tectonic zone has a weakened structure in the lower crust; and (iv physical properties of the QTP’s deep structure indicate that its

A model for the “quasi” 60 K plateau in the YBa2Cu3O6+x high-Tc compound

International Nuclear Information System (INIS)

Matic, V.M.; Lazarov, N.Dj.; Milic, M.

2013-01-01

Highlights: ► A theoretical model for the chain-to-plane charge transfer process in YBCO has been expounded. ► Explained how the critical chain length parameter influences the behaviour of p(x) and T c (x) characteristics. ► The origin of the classic (horizontal) 60 K plateau in T c (x) is explained. ► The “quasi” 60 K plateau is explained in terms of increased orthorhombicity in recently produced YBCO samples. - Abstract: The 60 K plateau of the YBa 2 Cu 3 O 6+x high-T c superconducting compound has traditionally been known as a horizontal section in its T c (x) characteristics within which the critical temperature maintains at a constant level T c ≈ 60 K. However, recent experiments on a series of high quality single crystals samples of the YBa 2 Cu 3 O 6+x compound (produced by improved techniques of sample preparation) have shown the 60 K plateau does not manifest itself anymore as a horizontal section of the T c (x), but emerges as a section over which T c (x) keeps on continuously rising (the “quasi” 60 K plateau). Here we propose a theoretical model that explains how the classical (horizontal) 60 K plateau naturally evolves into the “quasi” 60 K plateau, due to the improved orthorhombicity in the high quality single crystal material accompanied by longer CuO chains. The model assumes that short CuO chains do not contribute to the hole transfer from chains to CuO 2 layers, but only chains whose length is greater than, or equal to, a certain threshold length l cr . Our calculations point to a conclusion that this minimal number of oxygen atoms in a CuO chain, that is required to trigger the hole transfer, is equal to four. The calculated values for T c (x) are in a very good correlation with the corresponding experimentally obtained results.

Regional chemical setting of the Apollo 16 landing site and the importance of the Kant Plateau

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Andre, C. G.; El-Baz, F.

1982-01-01

Orbital X-ray data from the Apollo 16 region indicate that physiographic units identified before the lunar mission can be classified as chemical units as well. The Descartes Mountains, however, appear to be an extension of the Kant Plateau composition that is unusually anorthositic and resembles farside terra. The Cayley Plains have closer affinities to basaltic materials than terra materials, physically, spectrally and chemically. The Theophilus impact, 330 km east of the landing site, excavated magnesium-rich basalts from below less-magnesian flows in Mare Nectaris; but, mafic ejecta was substantially blocked from the Apollo 16 site by the Kant Plateau that rises 5 km above the level of the mare. Apollo 16 soil samples from stations selected to collect either Descartes Mountains material or Cayley Plains material were surprisingly similar. However, they do, indeed, show the chemical trends indicative of the two units as defined by the orbiting geochemistry detectors. The Kant Plateau and Descartes Mountains material may be among the rare nearside examples of a plagioclase-rich cumulate of the primordial magma ocean.

Uranium indicator plants of the Colorado plateau

International Nuclear Information System (INIS)

Massingill, G.L.

1979-01-01

Two methods of botanical prospecting for uranium deposits have been applied on the Colorado Plateau. The first, based on a chemical analysis of deep-rooted plants that absorb uranium from ore bodies, detects small but measurable amounts of the element in plants rooted in ore. A second method involves mapping the distribution of indicator plants because these plants are dependent--either directly or indirectly--upon the presence of abnormally high levels of elements in the parent soil or rock. Botanical prospecting studies made in ten districts have been productive. In the Thompson district, Grand County, Utah, five ore bodies were found solely on the basis of indicator plant data. 15 refs

Plateau inflation from random non-minimal coupling

International Nuclear Information System (INIS)

Broy, Benedict J.; Roest, Diederik

2016-06-01

A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength ξ of the order N 2 e . In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of ξ, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes ξ≅10 4 obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observables measured.

Accreted fragments of the Late Cretaceous Caribbean Colombian Plateau in Ecuador

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Mamberti, Marc; Lapierre, Henriette; Bosch, Delphine; Jaillard, Etienne; Ethien, Raynald; Hernandez, Jean; Polvé, Mireille

2003-02-01

The eastern part of the Western Cordillera of Ecuador includes fragments of an Early Cretaceous (≈123 Ma) oceanic plateau accreted around 85-80 Ma (San Juan-unit). West of this unit and in fault contact with it, another oceanic plateau sequence (Guaranda unit) is marked by the occurrence of picrites, ankaramites, basalts, dolerites and shallow level gabbros. A comparable unit is also exposed in northwestern coastal Ecuador (Pedernales unit). Picrites have LREE-depleted patterns, high ɛNd i and very low Pb isotopic ratios, suggesting that they were derived from an extremely depleted source. In contrast, the ankaramites and Mg-rich basalts are LREE-enriched and have radiogenic Pb isotopic compositions similar to the Galápagos HIMU component; their ɛNd i are slightly lower than those of the picrites. Basalts, dolerites and gabbros differ from the picrites and ankaramites by flat rare earth element (REE) patterns and lower ɛNd; their Pb isotopic compositions are intermediate between those of the picrites and ankaramites. The ankaramites, Mg-rich basalts, and picrites differ from the lavas from the San Juan-Multitud Unit by higher Pb ratios and lower ɛNd i. The Ecuadorian and Gorgona 88-86 Ma picrites are geochemically similar. The Ecuadorian ankaramites and Mg-rich basalts share with the 92-86 Ma Mg-rich basalts of the Caribbean-Colombian Oceanic Plateau (CCOP) similar trace element and Nd and Pb isotopic chemistry. This suggests that the Pedernales and Guaranda units belong to the Late Cretaceous CCOP. The geochemical diversity of the Guaranda and Pedernales rocks illustrates the heterogeneity of the CCOP plume source and suggests a multi-stage model for the emplacement of these rocks. Stratigraphic and geological relations strongly suggest that the Guaranda unit was accreted in the late Maastrichtian (≈68-65 Ma).

Distribution of hanging garden vegetation associations on the Colorado Plateau, USA

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James F. Fowler; N. L. Stanton; Ronald L. Hartman

2007-01-01

Hanging gardens are island-like habitats dominated by mesophytic-hydrophytic plant communities, growing on seeps on the xeric canyon walls of the Colorado Plateau in the American West. We measured the abundance of species and physical microhabitat characteristics of 73 individual hanging gardens during the growing seasons of 1991-1993. Cluster analysis of a simplified...

Comparison of time/phase lags in the hard state and plateau state of GRS 1915+105

Energy Technology Data Exchange (ETDEWEB)

Pahari, Mayukh; Yadav, J. S. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, India (MP) (India); Neilsen, Joseph [Boston University, Boston, MA 02215 (United States); Misra, Ranjeev [Inter University Center for Astronomy and Astrophysics, Pune (India); Uttley, Phil, E-mail: mp@tifr.res.in [Astronomical Institute, " Anton Pannekoek," University of Amsterdam, Science Park 904, 1098-XH Amsterdam (Netherlands)

2013-12-01

We investigate the complex behavior of energy- and frequency-dependent time/phase lags in the plateau state and the radio-quiet hard (χ) state of GRS 1915+105. In our timing analysis, we find that when the source is faint in the radio, quasi-periodic oscillations (QPOs) are observed above 2 Hz and typically exhibit soft lags (soft photons lag hard photons), whereas QPOs in the radio-bright plateau state are found below 2.2 Hz and consistently show hard lags. The phase lag at the QPO frequency is strongly anti-correlated with that frequency, changing sign at 2.2 Hz. However, the phase lag at the frequency of the first harmonic is positive and nearly independent of that frequency at ∼0.172 rad, regardless of the radio emission. The lag energy dependence at the first harmonic is also independent of radio flux. However, the lags at the QPO frequency are negative at all energies during the radio-quiet state, but lags at the QPO frequency during the plateau state are positive at all energies and show a 'reflection-type' evolution of the lag energy spectra with respect to the radio-quiet state. The lag energy dependence is roughly logarithmic, but there is some evidence for a break around 4-6 keV. Finally, the Fourier-frequency-dependent phase lag spectra are fairly flat during the plateau state, but increase from negative to positive during the radio-quiet state. We discuss the implications of our results in light of some generic models.

Pharmacodynamic Comparison of Rocuronium Bromide between Patients from the Plateau Area and from the Plain Area.

Science.gov (United States)

Xie, Min; Huang, Jianxin; Li, Peng; Ou, Zhiyan; Hou, Jing

2016-06-23

We aimed to conduct a pharmacodynamic comparison of rocuronium bromide between patients from the plateau area and from the plain area. A total of 104 patients who received laparoscopic cholecystectomy in Sichuan Provincial People's Hospital and Aba Autonomous Prefecture People's Hospital from October 2015 to December 2015 were included in this study. Among them, 46 patients were from the plateau area and 58 were from the plain area. Both groups received total intravenous anesthesia (TIVA) with a dose of 0.6mg/kg rocuronium bromide during induction. In the meantime, neuromuscular block was monitored using a train-of-four (TOF) stimulation mode. The onset time (time to achieve the lowest TOF value after the injection of rocuronium bromide), duration of maximal neuromuscular block (duration of lowest T1 value), time to 25% recovery, time to 75% recovery, recovery index (time from 25% recovery to 75% recovery), time to extubation, length of stay in Post Anesthesia Care Unit (PACU) and muscle strength upon PACU discharge were all recorded. The onset time, time to 25% recovery, time to 75% recovery and time to extubation were all significantly prolonged in patients from the plateau area after receiving one single dose of rocuronium bromide (P0.05). Compared to patients from the plain area, patients from the plateau area showed prolonged onset time of rocuronium bromide, reduced metabolic capabilities and longer duration of muscular relaxation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Understanding the circulation of geothermal waters in the Tibetan Plateau using oxygen and hydrogen stable isotopes

International Nuclear Information System (INIS)

Tan, Hongbing; Zhang, Yanfei; Zhang, Wenjie; Kong, Na; Zhang, Qing; Huang, Jingzhong

2014-01-01

Highlights: • Unique geothermal resources in Tibetan Plateau were discussed. • Isotopes were used to trace circulation of geothermal water. • Magmatic water mixing dominates geothermal water evolution. - Abstract: With the uplift of the Tibetan Plateau, many of the world’s rarest and most unique geothermal fields have been developed. This study aims to systematically analyze the characteristics of the hydrogen and oxygen isotopic data of geothermal, river, and lake waters to understand the circulation of groundwater and to uncover the mechanism of geothermal formation in the Tibetan Plateau. Field observations and isotopic data show that geothermal water has higher temperatures and hydraulic pressures, as well as more depleted D and 18 O isotopic compositions than river and lake waters. Thus, neither lakes nor those larger river waters are the recharge source of geothermal water. Snow-melt water in high mountains can vertically infiltrate and deeply circulate along some stretching tensile active tectonic belts or sutures and recharge geothermal water. After deep circulation, cold surface water evolves into high-temperature thermal water and is then discharged as springs at the surface again in a low area, under high water-head difference and cold–hot water density difference. Therefore, the large-scale, high-temperature, high-hydraulic-pressure geothermal systems in the Tibetan Plateau are developed and maintained by rapid groundwater circulation and the heat source of upwelled residual magmatic water. Inevitably, the amount of geothermal water will increase if global warming accelerates the melting of glaciers in high mountains

Future vegetation ecosystem response to warming climate over the Tibetan Plateau

Science.gov (United States)

Bao, Y.; Gao, Y.; Wang, Y.

2017-12-01

The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

MARGATS cruise: investigation of the deep internal structure and the heterogeneous margins of the Demerara plateau reveals a polyphased volcanic history

Science.gov (United States)

Graindorge, D.; Museur, T.; Roest, W. R.; Klingelhoefer, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Heuret, A.; Jean-Frederic, L.; Perrot, J.

2017-12-01

The MARGATS scientific cruise was carried out from October 20th to November 16th 2016 on board the R/V L'Atalante, offshore Suriname and French Guiana. This cruise is part of a program dedicated to the geological investigation of the continental margin, including the Demerara plateau, following the GUYAPLAC (2003), IGUANES (2013) and DRADEM (2016) cruises. The aim of MARGATS was to image the internal structure of the Demerara plateau and its different margins using coincident deep penetrating wide angle refraction and multi channel reflection seismic (MCS) methods. During the MARGATS experiment 171 OBS deployments were distributed along 4 wide-angle lines. Along each wide-angle line we also recorded coincident MCS data using a 3 km long 480 channel streamer. The dataset was completed by three MCS lines along the eastern part of the Demerara plateau. MCS MAR007 line which is coincident with line OBS MAR-3 was extended on land by 13 land stations deployed along the Maroni River. This line, together with MCS MAR001 and the coincident OBS MAR-1 line reveal the highly homogeneous deep structure of the internal part of the plateau. MCS MAR005 line, which is coincident with OBS MAR-2, MCS MAR006 line coincident with OBS MAR-4, MCS MAR002, MCS MAR003 and MCS MAR004 helps to elucidate the structural complexity of the northern transform margin and the eastern divergent margin of the plateau. These new datasets are highly complementary to the DRADEM dredge results which provide evidence for mid Jurassic volcanic rocks along the plateau and significant vertical displacements along the transform margin. These results allow to interpret the plateau as the remains of a huge jurassic volcanic divergent margin along the Central Atlantic ocean to the west, possibly remobilized during the cretaceous opening of the Equatorial Atlantic ocean as an highly oblique margin to the north and a divergent margin to the east in persistent presence of volcanism. This AGU session will be a great

The effect of the Asian Monsoon to the atmospheric boundary layer over the Tibetan Plateau

Science.gov (United States)

Li, Maoshan; Su, Zhongbo; Chen, Xuelong; Zheng, Donghai; Sun, Fanglin; Ma, Yaoming; Hu, Zeyong

2016-04-01

Modulation of the diurnal variations in the convective activities associated with day-by-day changes of surface flux and soil moisture was observed in the beginning of the monsoon season on the central Tibetan plateau (Sugimoto et al., 2008) which indicates the importance of land-atmosphere interactions in determining convective activities over the Tibetan plateau. Detailed interaction processes need to be studied by experiments designed to evaluate a set of hypotheses on mechanisms and linkages of these interactions. A possible function of vegetation to increase precipitation in cases of Tibetan High type was suggested by Yamada and Uyeda (2006). Use of satellite derived plateau scale soil moisture (Wen et al., 2003) enables the verification of these hypotheses (e.g. Trier et al. 2004). To evaluate these feedbacks, the mesoscale WRF model will be used because several numerical experiments are being conducted to improve the soil physical parameterization in the Noah land surface scheme in WRF so that the extreme conditions on the Tibetan plateau could be adequately represented (Van der Velde et al., 2009) such that the impacts on the structure of the atmospheric boundary layer can be assessed and improved. The Tibetan Observational Research Platform (TORP) operated by the Institute of Tibetan Plateau (Ma et al., 2008) will be fully utilized to study the characteristics of the plateau climate and different aspects of the WRF model will be evaluated using this extensive observation platform (e.g. Su et al., 2012). Recently, advanced studies on energy budget have been done by combining field and satellite measurements over the Tibetan Plateau (e.g. Ma et al., 2005). Such studies, however, were based on a single satellite observation and for a few days over an annual cycle, which are insufficient to reveal the relation between the land surface energy budget and the Asian monsoon over the Tibetan plateau. Time series analysis of satellite observations will provide the

Sustainable bioenergy production with little carbon debt in the Loess Plateau of China.

Science.gov (United States)

Liu, Wei; Peng, Cheng; Chen, Zhifen; Liu, Yue; Yan, Juan; Li, Jianqiang; Sang, Tao

2016-01-01

As a key strategy for mitigating global climate change, bioenergy production by reducing CO2 emissions plays an important role in ensuring sustainable development. However, land-use change by converting natural ecosystems into energy crop field could create a carbon debt at the beginning. Thus, the potential carbon debt calculation is necessary for determining a promising bioenergy crop production, especially in the region rich of marginal land. Here, we used high-resolution historical land-use data to identify the marginal land available and to evaluate the carbon debt of planting Miscanthus in the Loess Plateau, China. We found that there were 27.6 Mha for energy production and 9.7 Mha for ecological restoration, with total annual production of 0.41 billion tons of biomass. We also found that soil carbon sequestration and total CO2 mitigation were 9.3 Mt C year(-1) and 542 Mt year(-1), respectively. More importantly, the result showed that planting Miscanthus on marginal land in the Loess Plateau only took 0.97 years on average to repay the carbon debt. Our study demonstrated that Miscanthus production in suitable marginal land in the Loess Plateau can offer considerable renewable energy and mitigate climate change with little carbon debt. These results suggested that bioenergy production in the similar arid and semiarid region worldwide would contribute to carbon sequestration in the context of rapid climate change.

Low-energy fracture of posterolateral tibial plateau: treatment by a posterolateral prone approach.

Science.gov (United States)

Yu, Guang-Rong; Xia, Jiang; Zhou, Jia-Qian; Yang, Yun-Feng

2012-05-01

Most of the posterolateral tibial plateau fractures are caused by low-energy injury. The posterior fracture fragment could not be exposed and reduced well through traditional approaches. The aim of this study was to review the results of surgical treatment of this kind of fracture using posterolateral approach with patient in prone position. The low-energy posterolateral fracture is defined as the main part of articular depression or split fragment limited within the posterior half of the lateral column. Direct reduction and buttress plate fixation through the posterolateral prone approach was applied in all the patients. In our series, 15 of 132 (11.4%) patients with tibial plateau fractures were identified as low-energy posterolateral fractures. The clinical outcomes were available in 14 of the 15 patients through phone interviews and chart reviews. Mean follow-up was 35.1 months (range: 24-48 months). All the patients had anatomic or good reductions (≤ 2 mm step/gap). Average range of motion was 0.7 degrees to 123.2 degrees (5-110 degrees to 0-140 degrees). The complications were limited to one superficial wound infection, two slight flexion contractures, and five implants removal. The average modified hospital for special surgery knee score was 93.4 (range: 86-100). The posterolateral prone approach provides excellent visualization, which can facilitate the reduction and posterior buttress plate fixation for low-energy posterolateral tibial plateau fractures and shows encouraging results. V, therapeutic study.

[Treatment of Schatzker IV tibial plateau fractures with arthroscopy combined with MIPPO technique].

Science.gov (United States)

Li, Jian-Wen; Ye, Feng; Bi, Da-Wei; Zheng, Xiao-Dong; Chen, Jian-Liang

2018-02-25

To discusses the clinical effects of arthroscopy combined with minimally invasive percutaneous plate osteosynthesis(MIPPO) technology in treating Schatzker IV tibial plateau fractures. From January 2012 to January 2016, 19 patients with Schatzker type IV tibial plateau fractures were treated with arthroscopy combined with minimally invasive technique including 12 males and 7 females with an average age of 46.5 years old ranging from 19 to 78 years old. Patients were suffering knee pain, swelling, flexion and extension limited, and other symptoms preoperative. Patients were followed up and assessed by Rasmussen knee function score. No infection, traumatic arthritis, and knee joint valgus occurred after operation. Nineteen cases were followed up for 12 to 24 months with an average of 18.6 months. Fracture healing time was 3 to 5 months with an average of 3.8 months. The knee pain and limited mobility improved significantly. The range of autonomic movement of joints was from 90 to 136 degrees. According to Rasmussen functional score criteria, the total score was 27.00±2.49, the result was excellent in 16 cases, good in 2 cases, fair in 1 case. Arthroscopic treatment for Schatzker type IV tibial plateau fractures combined with MIPPO can simultaneously treat internal structural injuries such as meniscus and other knee joints, with less trauma, fewer complications, and faster joint function recovery, but we must strictly grasp surgical indications and avoid expanding injuries. Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.

Agrobiodiversity of cactus pear (Opuntia, Cactaceae in the Meridional Highlands Plateau of Mexico

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Juan Antonio Reyes-Agüero

2011-08-01

Full Text Available Mexico is characterized by a remarkable richness of Opuntia, mostly at the Meridional Highlands Plateau; it is also here where the greatest richness of Opuntia variants occurs. Most of these variants have been maintained in homegardens; however, the gathering process which originated these homegardens has been disrupted over the past decades, as a result of social change and the destruction of large wild nopaleras. If the variants still surviving in homegardens are lost, these will be hard to recover, that is, the millenary cultural heritage from the human groups that populated the Mexican Meridional Highland Plateau will be lost forever. This situation motivated the preparation of a catalogue that records the diversity of wild and cultivated Opuntia variants living in the meridional Highlands Plateau. To this end, 379 samples were obtained in 29 localities, between 1998 and 2003. The information was processed through Twinspan. All specimens were identified and preserved in herbaria. Botanical keys and descriptions were elaborated. The catalogue includes information on 126 variants comprising 18 species. There were species with only one variant (Opuntia atropes, O. cochinera, O. jaliscana, O. leucotricha, O. rzedowskii and O. velutina, two (O. durangensis, O. lindheimeri, O. phaeacantha and O. robusta, five (O. joconostle and O. lasiacantha, seven (O. chavena, 12 (O. hyptiacantha and O. streptacantha, 15 (O. ficus-indica, 22 (O. albicarpa, and up to 34 (O. megacantha. Additionally, 267 common cactus pear names were related to those variants.

Threshold friction velocity influenced by wetness of soils within the Columbia Plateau

Science.gov (United States)

Windblown dust impacts air quality in the Columbia Plateau of the U.S. Pacific Northwest. Wind erosion of agricultural lands, which is the predominate source of windblown dust in the region, occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. Soil moisture...

Generalizing ecological site concepts of the Colorado Plateau for landscape-level applications

Science.gov (United States)

The Colorado Plateau is an iconic landscape of the American West— containing dozens of national parks, monuments, historic sites, and several UNESCO World Heritage Sites— including some of the Nation’ s most recognizable landmarks, such as the Grand Canyon and the Arches National Park. The concentra...