WorldWideScience

Sample records for terrestrial impact structure

  1. Impact of non-native terrestrial mammals on the structure of the terrestrial mammal food web of Newfoundland, Canada.

    Directory of Open Access Journals (Sweden)

    Justin S Strong

    Full Text Available The island of Newfoundland is unique because it has as many non-native terrestrial mammals as native ones. The impacts of non-native species on native flora and fauna can be profound and invasive species have been identified as one of the primary drivers of species extinction. Few studies, however, have investigated the effects of a non-native species assemblage on community and ecosystem properties. We reviewed the literature to build the first terrestrial mammal food web for the island of Newfoundland and then used network analyses to investigate how the timing of introductions and trophic position of non-native species has affected the structure of the terrestrial mammal food web in Newfoundland. The first non-native mammals (house mouse and brown rat became established in Newfoundland with human settlement in the late 15th and early 16th centuries. Coyotes and southern red-backed voles are the most recent mammals to establish themselves on the island in 1985 and 1998, respectively. The fraction of intermediate species increased with the addition of non-native mammals over time whereas the fraction of basal and top species declined over time. This increase in intermediate species mediated by non-native species arrivals led to an overall increase in the terrestrial mammal food web connectance and generality (i.e. mean number of prey per predator. This diverse prey base and sources of carrion may have facilitated the natural establishment of coyotes on the island. Also, there is some evidence that the introduction of non-native prey species such as the southern red-backed vole has contributed to the recovery of the threatened American marten. Long-term monitoring of the food web is required to understand and predict the impacts of the diverse novel interactions that are developing in the terrestrial mammal food web of Newfoundland.

  2. Half a century of progress in research on terrestrial impact structures: A review

    Science.gov (United States)

    McCall, G. J. H.

    2009-02-01

    The author, who investigated the Wolfe Creek, Australia, in 1962 and edited two Benchmark Sets of Readings on Meteorite Craters and possible Astroblemes in 1977 and 1979, reviews the state of knowledge at the present time. The text is concerned with terrestrial impact structures, geological features, without any consideration of extraterrestrial analogues. A handful of definitive publications are drawn on to present the story of terrestrial impact in a single article. The text covers historical aspects (briefly); the effect of target variations; the paucity of human observation of such large-scale events; distinction from volcanic (endogenous) structures; modification by geological processes; the transience of the crater initially formed on the target, and its subsequent modifications; the global geographic distribution of the 174 structures now listed (of which a number are dubious attributions); their distribution in geological time (many ages being known only known to wide limits, maximum or minimum values); their size distribution; calculations of impact frequencies; shock effects; processes on impact; the stages of formation; impact into shallow marine and deep sea targets; impacts on ice (about which little is known); and finally the input of impact into biotic extinctions. In this last lengthy section, the summaries of the conclusions of scientists researching impact on Earth and palaeontologists researching biotic impact are set side by side. It is concluded that, if the recent foraminiferal evidence obtained by Gerta Keller and associates is taken at its face value, the case of impact as a sole agent in extinction is non-existent: biotic extinction is clearly a complex process involving a number of causes, in some cases it was staggered in time, and different sets of organisms responded quite differently and surprisingly, even in the same extinction event. Extraterrestrial impact may have been one of the causes in some cases, but it may have been regional

  3. Structure of the terrestrial planets

    International Nuclear Information System (INIS)

    Lyttleton, R.A.

    1977-01-01

    Recent reviews (cf. Runcorn, 1968; or Cook, 1972, 1975) on the structure of the planets omit reference to the phase-change hypothesis for the nature of the terrestrial core, despite that numerous prior predictions of the theory based on this hypothesis have subsequently been borne out as correct. These reviews also ignore the existence of theoretical calculations of the internal structure of Venus which can be computed with high accuracy by use of the terrestrial seismic data. Several examples of numerous mistakes committed in these reviews are pointed out. (Auth.)

  4. Impact of the method of registering Terrestrial Laser Scanning data on the quality of documenting cultural heritage structures

    Directory of Open Access Journals (Sweden)

    M. Kedzierski

    2015-08-01

    Full Text Available When documenting historical structures and objects, especially delicate artefacts such as pieces of sacred art, only techniques that allow remote, non-contact methods that enable the most precise measurements should be used to obtain data. TLS can be considered as such a technique however in order to obtain complete information for the entire structure, there is usually a need to acquire data from more than one measuring station. In this case, the most important and essential step of processing TLS data is the registration of scans. The paper contains a description of research and analyses concerning the registration of point clouds using three methods: manual, automatic and a combination of the two. The research was carried on measurement data from a historical synagogue. The structure was divided into three parts – three scans. The accuracy with which these scans were registered was assessed and a 3D model of the interior was created.

  5. Some Studies of Terrestrial Impact Cratering Rate

    Directory of Open Access Journals (Sweden)

    Jetsu L.

    2011-06-01

    Full Text Available In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the “human signal” caused by the rounding of these data into integer numbers. The second study confirmed that the original 28.4 Myr periodicity detection was not significant. The third study revealed that the quality and the quantity of the currently available data would allow detection of real periodicity only if all impacts have been periodic, which cannot be the case. The detection of a periodic signal, if present, requires that more craters should be discovered and the accuracy of age estimates improved. If we sometimes will be able to find the difference between the craters caused by asteroid and comet impacts, the aperiodic component could be removed. The lunar impact craters may eventually provide the required supplementary data.

  6. Geological remote sensing signatures of terrestrial impact craters

    International Nuclear Information System (INIS)

    Garvin, J.B.; Schnetzler, C.; Grieve, R.A.F.

    1988-01-01

    Geological remote sensing techniques can be used to investigate structural, depositional, and shock metamorphic effects associated with hypervelocity impact structures, some of which may be linked to global Earth system catastrophies. Although detailed laboratory and field investigations are necessary to establish conclusive evidence of an impact origin for suspected crater landforms, the synoptic perspective provided by various remote sensing systems can often serve as a pathfinder to key deposits which can then be targetted for intensive field study. In addition, remote sensing imagery can be used as a tool in the search for impact and other catastrophic explosion landforms on the basis of localized disruption and anomaly patterns. In order to reconstruct original dimensions of large, complex impact features in isolated, inaccessible regions, remote sensing imagery can be used to make preliminary estimates in the absence of field geophysical surveys. The experienced gained from two decades of planetary remote sensing of impact craters on the terrestrial planets, as well as the techniques developed for recognizing stages of degradation and initial crater morphology, can now be applied to the problem of discovering and studying eroded impact landforms on Earth. Preliminary results of remote sensing analyses of a set of terrestrial impact features in various states of degradation, geologic settings, and for a broad range of diameters and hence energies of formation are summarized. The intention is to develop a database of remote sensing signatures for catastrophic impact landforms which can then be used in EOS-era global surveys as the basis for locating the possibly hundreds of missing impact structures

  7. Use of a mobile terrestrial laser system to quantify the impact of rigid coastal protective structures on sandy beaches, Quebec, Canada

    Science.gov (United States)

    Van-Wierts, S.; Bernatchez, P.

    2012-04-01

    Coastal erosion is an important issue within the St-Lawrence estuary and gulf, especially in zones of unconsolidated material. Wide beaches are important coastal environments; they act as a buffer against breaking waves by absorbing and dissipating their energy, thus reducing the rate of coastal erosion. They also offer protection to humans and nearby ecosystems, providing habitat for plants, animals and lifeforms such as algae and microfauna. Conventional methods, such as aerial photograph analysis, fail to adequately quantify the morphosedimentary behavior of beaches at the scale of a hydrosedimentary cells. The lack of reliable and quantitative data leads to considerable errors of overestimation and underestimation of sediment budgets. To address these gaps and to minimize acquisition costs posed by airborne LiDAR survey, a mobile terrestrial LiDAR has been set up to acquire topographic data of the coastal zone. The acquisition system includes a LiDAR sensor, a high precision navigation system (GPS-INS) and a video camera. Comparison of LiDAR data with 1050 DGPS control points shows a vertical mean absolute error of 0.1 m in beach areas. The extracted data is used to calculate sediment volumes, widths, slopes, and a sediment budget index. A high accuracy coastal characterization is achieved through the integration of laser data and video. The main objective of this first project using this system is to quantify the impact of rigid coastal protective structures on sediment budget and beach morphology. Results show that the average sediment volume of beaches located before a rock armour barrier (12 m3/m) were three times narrower than for natural beaches (35,5 m3/m). Natural beaches were also found to have twice the width (25.4 m) of the beaches bordering inhabited areas (12.7 m). The development of sediment budget index for beach areas is an excellent proxy to quickly identify deficit areas and therefore the coastal segments most at risk of erosion. The obtained

  8. How lichens impact on terrestrial community and ecosystem properties.

    Science.gov (United States)

    Asplund, Johan; Wardle, David A

    2017-08-01

    Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include

  9. Structural Analysis of Hand Drawn Bumblebee Bombus terrestris Silk

    Directory of Open Access Journals (Sweden)

    Andrea L. Woodhead

    2016-07-01

    Full Text Available Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine, poly(alanine-glycine, phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73% while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results.

  10. Ar-Ar dating techniques for terrestrial meteorite impacts

    Science.gov (United States)

    Kelley, S. P.

    2003-04-01

    The ages of the largest (>100 km) known impacts on Earth are now well characterised. However the ages of many intermediate sized craters (20-100 km) are still poorly known, often the only constraints are stratigraphic - the difference between the target rock age and the age of crater filling sediments. The largest impacts result in significant melt bodies which cool to form igneous rocks and can be dated using conventional radiometric techniques. Smaller impacts give rise to thin bands of melted rock or melt clasts intimately mixed with country rock clasts in breccia deposits, and present much more of a challenge to dating. The Ar-Ar dating technique can address a wide variety of complex and heterogeneous samples associated with meteorite impacts and obtain reasonable ages. Ar-Ar results will be presented from a series of terrestrial meteorite impact craters including Boltysh (65.17±0.64 Ma, Strangways (646±42 Ma), and St Martin (220±32 Ma) and a Late Triassic spherule bed, possibly representing distal deposits from Manicouagan (214±1 Ma) crater. Samples from the Boltysh and Strangways craters demonstrate the importance of rapid cooling upon the retention of old ages in glassy impact rocks. A Late Triassic spherule bed in SW England is cemented by both carbonate and K-feldspar cements allowing Ar-Ar dating of fine grained cement to place a mimimum age upon the age of the associated impact. An age of 214.7±2.5 Ma places the deposit with errors of the age of the Manicouagan impact, raising the possibility that it may represent a distal deposit (the deposit lay around 2000 km away from the site of the Manicouagan crater during the Late Triassic). Finally the limits of the technique will be demonstrated using an attempt to date melt rocks from the St Martin Crater in Canada.

  11. Estimating Tropical Forest Structure Using a Terrestrial Lidar.

    Science.gov (United States)

    Palace, Michael; Sullivan, Franklin B; Ducey, Mark; Herrick, Christina

    2016-01-01

    Forest structure comprises numerous quantifiable biometric components and characteristics, which include tree geometry and stand architecture. These structural components are important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying biometric properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar). This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS) system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in a predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs) and calculated a series of parameters including entropy, Fast Fourier Transform (FFT), number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using a series of multiple linear regressions, all of which converged on significant relationships with the strongest relationship being for mean crown depth (r2 = 0.88, p < 0.001, RMSE = 1.04 m). Tree density was found to have the poorest significant relationship (r2 = 0.50, p < 0.01, RMSE = 153.28 n ha-1). We found a significant relationship between basal area and lidar metrics (r2 = 0.75, p < 0.001, RMSE = 3.76 number ha-1). Parameters selected in our models varied, thus indicating the potential relevance of multiple features in canopy profiles and geometry that are related to field-measured structure. Models for biomass estimation included structural canopy

  12. Estimating Tropical Forest Structure Using a Terrestrial Lidar.

    Directory of Open Access Journals (Sweden)

    Michael Palace

    Full Text Available Forest structure comprises numerous quantifiable biometric components and characteristics, which include tree geometry and stand architecture. These structural components are important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying biometric properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar. This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in a predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs and calculated a series of parameters including entropy, Fast Fourier Transform (FFT, number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using a series of multiple linear regressions, all of which converged on significant relationships with the strongest relationship being for mean crown depth (r2 = 0.88, p < 0.001, RMSE = 1.04 m. Tree density was found to have the poorest significant relationship (r2 = 0.50, p < 0.01, RMSE = 153.28 n ha-1. We found a significant relationship between basal area and lidar metrics (r2 = 0.75, p < 0.001, RMSE = 3.76 number ha-1. Parameters selected in our models varied, thus indicating the potential relevance of multiple features in canopy profiles and geometry that are related to field-measured structure. Models for biomass estimation included

  13. Application of terrestrial laser scanning for measuring tree crown structures

    International Nuclear Information System (INIS)

    Pretzsch, H.; Seifert, S.; Huang, P.

    2011-01-01

    This paper addresses the potential of terrestrial laser scanning (TLS) for describing and modelling of tree crown structure and dynamics. We first present a general approach for the metabolic and structural scaling of tree crowns. Out of this approach we emphasize those normalization and scaling parameters which become accessible by TLS. For example we show how the individual tree leaf area index, convex hull, and its space-filling by leaves can be extracted out of laser scan data. This contributes to a theoretical and empirical substantiation of crown structure models which were missing so far for e.g. quantification of structural and species diversity in forest stands, inventory of crown biomass, species detection by remote sensing, and understanding of self- and alien-thinning in pure and mixed stands. Up to now works on this topic delivered a rather scattered empirical knowledge mainly by single inventories of trees and stands. In contrast, we recommend to start with a model approach, and to complete existing data with repeated TLS inventories in order to come to a consistent and theoretically based model of tree crowns. (author) [de

  14. Wetland Microtopographic Structure is Revealed with Terrestrial Laser Scanning

    Science.gov (United States)

    Diamond, J.; Stovall, A. E.; Mclaughlin, D. L.; Slesak, R.

    2017-12-01

    Wetland microtopographic structure and its function has been the subject of research for decades, and several investigations suggest that microtopography is generated by autogenic ecohydrologic processes. But due to the difficulty of capturing the true spatial variability of wetland microtopography, many of the hypotheses for self-organization have remained elusive to test. We employ a novel method of Terrestrial Laser Scanning (TLS) that reveals an unprecedented high-resolution (structure of wetland microtopography in 10 black ash (Fraxinus nigra) stands of northern Minnesota, USA. Here we present the first efforts to synthesize this information and show that TLS provides a good representation of real microtopographic structure, where TLS accurately measured hummock height, but occlusion of low points led to a slight negative bias. We further show that TLS can accurately locate microtopographic high points (hummocks), as well as estimate their height and area. Using these new data, we estimate distributions in both microtopographic elevation and hummock area in each wetland and relate these to monitored hydrologic regime; in doing so, we test hypotheses linking emergent microtopographic patterns to putative hydrologic controls. Finally, we discuss future efforts to enumerate consequent influences of microtopography on wetland systems (soil properties and vegetation composition).

  15. Risk of severe climate change impact on the terrestrial biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Heyder, Ursula; Schaphoff, Sibyll; Gerten, Dieter; Lucht, Wolfgang, E-mail: Ursula.Heyder@pik-potsdam.de, E-mail: Sibyll.Schaphoff@pik-potsdam.de [Potsdam Institute for Climate Impact Research, Telegraphenberg A62, 14473 Potsdam (Germany)

    2011-07-15

    The functioning of many ecosystems and their associated resilience could become severely compromised by climate change over the 21st century. We present a global risk analysis of terrestrial ecosystem changes based on an aggregate metric of joint changes in macroscopic ecosystem features including vegetation structure as well as carbon and water fluxes and stores. We apply this metric to global ecosystem simulations with a dynamic global vegetation model (LPJmL) under 58 WCRP CMIP3 climate change projections. Given the current knowledge of ecosystem processes and projected climate change patterns, we find that severe ecosystem changes cannot be excluded on any continent. They are likely to occur (in > 90% of the climate projections) in the boreal-temperate ecotone where heat and drought stress might lead to large-scale forest die-back, along boreal and mountainous tree lines where the temperature limitation will be alleviated, and in water-limited ecosystems where elevated atmospheric CO{sub 2} concentration will lead to increased water use efficiency of photosynthesis. Considerable ecosystem changes can be expected above 3 K local temperature change in cold and tropical climates and above 4 K in the temperate zone. Sensitivity to temperature change increases with decreasing precipitation in tropical and temperate ecosystems. In summary, there is a risk of substantial restructuring of the global land biosphere on current trajectories of climate change.

  16. Risk of severe climate change impact on the terrestrial biosphere

    International Nuclear Information System (INIS)

    Heyder, Ursula; Schaphoff, Sibyll; Gerten, Dieter; Lucht, Wolfgang

    2011-01-01

    The functioning of many ecosystems and their associated resilience could become severely compromised by climate change over the 21st century. We present a global risk analysis of terrestrial ecosystem changes based on an aggregate metric of joint changes in macroscopic ecosystem features including vegetation structure as well as carbon and water fluxes and stores. We apply this metric to global ecosystem simulations with a dynamic global vegetation model (LPJmL) under 58 WCRP CMIP3 climate change projections. Given the current knowledge of ecosystem processes and projected climate change patterns, we find that severe ecosystem changes cannot be excluded on any continent. They are likely to occur (in > 90% of the climate projections) in the boreal-temperate ecotone where heat and drought stress might lead to large-scale forest die-back, along boreal and mountainous tree lines where the temperature limitation will be alleviated, and in water-limited ecosystems where elevated atmospheric CO 2 concentration will lead to increased water use efficiency of photosynthesis. Considerable ecosystem changes can be expected above 3 K local temperature change in cold and tropical climates and above 4 K in the temperate zone. Sensitivity to temperature change increases with decreasing precipitation in tropical and temperate ecosystems. In summary, there is a risk of substantial restructuring of the global land biosphere on current trajectories of climate change.

  17. Quantifying Vegetation Structure with Lightweight, Rapid-Scanning Terrestrial Lidar

    Science.gov (United States)

    Paynter, I.; Genest, D.; Saenz, E. J.; Strahler, A. H.; Li, Z.; Peri, F.; Schaaf, C.

    2016-12-01

    Light Detection and Ranging (lidar) is proving a competent technology for observing vegetation structure. Terrestrial laser scanners (TLS) are ground-based instruments which utilize hundreds of thousands to millions of lidar observations to provide detailed structural and reflective information of their surroundings. TLS has enjoyed initial success as a validation tool for satellite and airborne estimates of vegetation structure, and are producing independent estimates with increasing accuracy. Reconstruction techniques for TLS observations of vegetation have also improved rapidly, especially for trees. However, uncertainties and challenges still remain in TLS modelling of vegetation structure, especially in geometrically complex ecosystems such as tropical forests (where observation extent and density is hampered by occlusion) and highly temporally dynamic coastal ecosystems (such as saltmarshes and mangroves), where observations may be restricted to narrow microstates. Some of these uncertainties can be mitigated, and challenges met, through the use of lidar instruments optimized for favorable deployment logistics through low weight, rapid scanning, and improved durability. We have conducted studies of vegetation structure in temperate and tropical forests, saltmarshes and mangroves, utilizing a highly portable TLS with considerable deployment flexibility, the Compact Biomass Lidar (CBL). We show results from studies in the temperate Long Term Ecological Research site of Harvard Forest (MA, USA); the tropical forested long-term Carbono sites of La Selva Biological Station (Sarapiqui, Costa Rica); and the saltmarsh LTER of Plum Island (MA, USA). These results demonstrate the improvements to observations in these ecosystems which are facilitated by the specifications of the CBL (and similar TLS) which are optimized for favorable deployment logistics and flexibility. We show the benefits of increased numbers of scanning positions, and specialized deployment

  18. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    Science.gov (United States)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  19. Quantifying Standing Dead Tree Volume and Structural Loss with Voxelized Terrestrial Lidar Data

    Science.gov (United States)

    Popescu, S. C.; Putman, E.

    2017-12-01

    Standing dead trees (SDTs) are an important forest component and impact a variety of ecosystem processes, yet the carbon pool dynamics of SDTs are poorly constrained in terrestrial carbon cycling models. The ability to model wood decay and carbon cycling in relation to detectable changes in tree structure and volume over time would greatly improve such models. The overall objective of this study was to provide automated aboveground volume estimates of SDTs and automated procedures to detect, quantify, and characterize structural losses over time with terrestrial lidar data. The specific objectives of this study were: 1) develop an automated SDT volume estimation algorithm providing accurate volume estimates for trees scanned in dense forests; 2) develop an automated change detection methodology to accurately detect and quantify SDT structural loss between subsequent terrestrial lidar observations; and 3) characterize the structural loss rates of pine and oak SDTs in southeastern Texas. A voxel-based volume estimation algorithm, "TreeVolX", was developed and incorporates several methods designed to robustly process point clouds of varying quality levels. The algorithm operates on horizontal voxel slices by segmenting the slice into distinct branch or stem sections then applying an adaptive contour interpolation and interior filling process to create solid reconstructed tree models (RTMs). TreeVolX estimated large and small branch volume with an RMSE of 7.3% and 13.8%, respectively. A voxel-based change detection methodology was developed to accurately detect and quantify structural losses and incorporated several methods to mitigate the challenges presented by shifting tree and branch positions as SDT decay progresses. The volume and structural loss of 29 SDTs, composed of Pinus taeda and Quercus stellata, were successfully estimated using multitemporal terrestrial lidar observations over elapsed times ranging from 71 - 753 days. Pine and oak structural loss rates

  20. Large-scale impact cratering on the terrestrial planets

    International Nuclear Information System (INIS)

    Grieve, R.A.F.

    1982-01-01

    The crater densities on the earth and moon form the basis for a standard flux-time curve that can be used in dating unsampled planetary surfaces and constraining the temporal history of endogenic geologic processes. Abundant evidence is seen not only that impact cratering was an important surface process in planetary history but also that large imapact events produced effects that were crucial in scale. By way of example, it is noted that the formation of multiring basins on the early moon was as important in defining the planetary tectonic framework as plate tectonics is on the earth. Evidence from several planets suggests that the effects of very-large-scale impacts go beyond the simple formation of an impact structure and serve to localize increased endogenic activity over an extended period of geologic time. Even though no longer occurring with the frequency and magnitude of early solar system history, it is noted that large scale impact events continue to affect the local geology of the planets. 92 references

  1. Structural monitoring of tunnels using terrestrial laser scanning

    NARCIS (Netherlands)

    Lindenbergh, R.C.; Uchanski, L.; Bucksch, A.; Van Gosliga, R.

    2009-01-01

    In recent years terrestrial laser scanning is rapidly evolving as a surveying technique for the monitoring of engineering objects like roof constructions, mines, dams, viaducts and tunnels. The advantage of laser scanning above traditional surveying methods is that it allows for the rapid

  2. Impact structures in Africa: A review

    Science.gov (United States)

    Reimold, Wolf Uwe; Koeberl, Christian

    2014-01-01

    More than 50 years of space and planetary exploration and concomitant studies of terrestrial impact structures have demonstrated that impact cratering has been a fundamental process – an essential part of planetary evolution – ever since the beginning of accretion and has played a major role in planetary evolution throughout the solar system and beyond. This not only pertains to the development of the planets but to evolution of life as well. The terrestrial impact record represents only a small fraction of the bombardment history that Earth experienced throughout its evolution. While remote sensing investigations of planetary surfaces provide essential information about surface evolution and surface processes, they do not provide the information required for understanding the ultra-high strain rate, high-pressure, and high-temperature impact process. Thus, hands-on investigations of rocks from terrestrial impact craters, shock experimentation for pressure and temperature calibration of impact-related deformation of rocks and minerals, as well as parameter studies pertaining to the physics and chemistry of cratering and ejecta formation and emplacement, and laboratory studies of impact-generated lithologies are mandatory tools. These, together with numerical modeling analysis of impact physics, form the backbone of impact cratering studies. Here, we review the current status of knowledge about impact cratering – and provide a detailed account of the African impact record, which has been expanded vastly since a first overview was published in 1994. No less than 19 confirmed impact structures, and one shatter cone occurrence without related impact crater are now known from Africa. In addition, a number of impact glass, tektite and spherule layer occurrences are known. The 49 sites with proposed, but not yet confirmed, possible impact structures contain at least a considerable number of structures that, from available information, hold the promise to be able to

  3. Structural parallels between terrestrial microbialites and Martian sediments: are all cases of `Pareidolia'?

    Science.gov (United States)

    Rizzo, Vincenzo; Cantasano, Nicola

    2017-10-01

    The study analyses possible parallels of the microbialite-known structures with a set of similar settings selected by a systematic investigation from the wide record and data set of images shot by NASA rovers. Terrestrial cases involve structures both due to bio-mineralization processes and those induced by bacterial metabolism, that occur in a dimensional field longer than 0.1 mm, at micro, meso and macro scales. The study highlights occurrence on Martian sediments of widespread structures like microspherules, often organized into some higher-order settings. Such structures also occur on terrestrial stromatolites in a great variety of `Microscopic Induced Sedimentary Structures', such as voids, gas domes and layer deformations of microbial mats. We present a suite of analogies so compelling (i.e. different scales of morphological, structural and conceptual relevance), to make the case that similarities between Martian sediment structures and terrestrial microbialites are not all cases of `Pareidolia'.

  4. Impact of an asteroid or comet in the ocean and extinction of terrestrial life

    Science.gov (United States)

    Ahrens, T. J.; Okeefe, J. D.

    1982-01-01

    Finite difference calculations describing the impact mechanics associated with a 10 to 30 km diameter silicate or water object impacting a 5 km deep ocean overlying a silicate solid planet demonstrate that from 12 to 15% of the bolide energy resides in the water. It is speculated that minimal global tsunami run-up heights on the continents would be 300-400 meters, and that such waves would inundate all low altitude continental areas, and strip and silt-over virtually all vegetation. As a result the terrestrial animal food chain would be seriously perturbed. This could in turn cause extinction of large terrestrial animals.

  5. Differential melt scaling for oblique impacts on terrestrial planets

    Science.gov (United States)

    Abramov, Oleg; Wong, Stephanie M. Wong; Kring, David A. Kring

    2012-01-01

    Analytical estimates of melt volumes produced by a given projectile and contained in a given impact crater are derived as a function of impact velocity, impact angle, planetary gravity, target and projectile densities, and specific internal energy of melting. Applications to impact events and impact craters on the Earth, Moon, and Mars are demonstrated and discussed. The most probable oblique impact (45°) produces ∼1.6 times less melt volume than a vertical impact, and ∼1.6 and 3.7 times more melt volume than impacts with 30° and 15° trajectories, respectively. The melt volume for a particular crater diameter increases with planetary gravity, so a crater on Earth should have more melt than similar-size craters on Mars and the Moon. The melt volume for a particular projectile diameter does not depend on gravity, but has a strong dependence on impact velocity, so the melt generated by a given projectile on the Moon is significantly larger than on Mars. Higher surface temperatures and geothermal gradients increase melt production, as do lower energies of melting. Collectively, the results imply thinner central melt sheets and a smaller proportion of melt particles in impact breccias on the Moon and Mars than on Earth. These effects are illustrated in a comparison of the Chicxulub crater on Earth, linked to the Cretaceous–Tertiary mass extinction, Gusev crater on Mars, where the Mars Exploration Rover Spirit landed, and Tsiolkovsky crater on the Moon. The results are comparable to those obtained from field and spacecraft observations, other analytical expressions, and hydrocode simulations.

  6. Large impacts around a solar-analog star in the era of terrestrial planet formation.

    Science.gov (United States)

    Meng, Huan Y A; Su, Kate Y L; Rieke, George H; Stevenson, David J; Plavchan, Peter; Rujopakarn, Wiphu; Lisse, Carey M; Poshyachinda, Saran; Reichart, Daniel E

    2014-08-29

    The final assembly of terrestrial planets occurs via massive collisions, which can launch copious clouds of dust that are warmed by the star and glow in the infrared. We report the real-time detection of a debris-producing impact in the terrestrial planet zone around a 35-million-year-old solar-analog star. We observed a substantial brightening of the debris disk at a wavelength of 3 to 5 micrometers, followed by a decay over a year, with quasi-periodic modulations of the disk flux. The behavior is consistent with the occurrence of a violent impact that produced vapor out of which a thick cloud of silicate spherules condensed that were then ground into dust by collisions. These results demonstrate how the time domain can become a new dimension for the study of terrestrial planet formation. Copyright © 2014, American Association for the Advancement of Science.

  7. Large impact events and atmospheric evolution on the terrestrial planets

    International Nuclear Information System (INIS)

    Grinspoon, D.H.

    1989-01-01

    The first task undertaken is the characterization of the impact rates in the inner solar system during the present time, and during the first billion years of Solar System history when the flux was changing rapidly. Once defined, these fluxes are used to model the long term cumulative effect of multiple impacts on planetary atmospheres. The implications of cometary impacts on evolution of the water and deuterium abundances on Venus are examined. The short lifetime of water on Venus suggests that the water abundance is in quasi-steady-state balance between loss by escape and replenishment by infall. In addition, the observed deuterium-to-hydrogen ratio on Venus is consistent with a steady state and does not necessarily imply a past water excess. Results are presented of a model incorporating a stochastic cometary source and nonthermal escape of hydrogen that produces the observed water abundance and D/H ratio. The stochastic variability of each of these quantities is shown to be large. Water on Venus is likely to be in a near steady state mediated by large comet impacts. The early history of water on the planet has been obscured by a history of random impacts. A study of the effects of impact-generated dust clouds on the primitive Earth leads to the conclusion that such clouds were significant perturbers of the early climate. The Earth was shrouded by an optically-thick dust cloud for ∼150-250 m.y.. During this time the surface temperature was equal to the planetary equilibrium temperature unless significant heating by impacts or surface heat flow existed beneath the dust cloud. The epoch of continuous dust shrouding was followed by a period of stochastically intermittent dust clouds occurring at greater intervals as the early intense bombardment subsided towards the present day flux

  8. Developing Conceptual Models for Assessing Climate Change Impacts to Contaminant Availability in Terrestrial Ecosystems

    Science.gov (United States)

    2015-03-01

    Greenberg 2005), effects of dredged material (PIANC 2006), and ecosystem restoration (Fischenich 2008) among others. The process of developing a conceptual...Impacts to Contaminant Availability in Terrestrial Ecosystems by Burton C. Suedel, Nathan R. Beane, Eric R. Britzke, Cheryl R. Montgomery, and...are generally project or problem specific. Building a CM includes determining the components of the ecosystem , identifying relationships linking these

  9. Impacts of Climate Chnage on Terrestrial Ecosystems Functioning - An Overview

    DEFF Research Database (Denmark)

    Beier, Claus; Ambus, Per; Amdal, M. F.

    the different climate change factors may not belinear and/or predictable. Computer models may predict some ofthese interactions relatively well (e.g. resource limitations due toincreased growth), while other interactions may be unpredictable.8 beier, c., et al.The assumption that the impact of the "climate...

  10. Human impacts on terrestrial hydrology: climate change versus pumping and irrigation

    International Nuclear Information System (INIS)

    Ferguson, Ian M; Maxwell, Reed M

    2012-01-01

    Global climate change is altering terrestrial water and energy budgets, with subsequent impacts on surface and groundwater resources; recent studies have shown that local water management practices such as groundwater pumping and irrigation similarly alter terrestrial water and energy budgets over many agricultural regions, with potential feedbacks on weather and climate. Here we use a fully-integrated hydrologic model to directly compare effects of climate change and water management on terrestrial water and energy budgets of a representative agricultural watershed in the semi-arid Southern Great Plains, USA. At local scales, we find that the impacts of pumping and irrigation on latent heat flux, potential recharge and water table depth are similar in magnitude to the impacts of changing temperature and precipitation; however, the spatial distributions of climate and management impacts are substantially different. At the basin scale, the impacts on stream discharge and groundwater storage are remarkably similar. Notably, for the watershed and scenarios studied here, the changes in groundwater storage and stream discharge in response to a 2.5 °C temperature increase are nearly equivalent to those from groundwater-fed irrigation. Our results imply that many semi-arid basins worldwide that practice groundwater pumping and irrigation may already be experiencing similar impacts on surface water and groundwater resources to a warming climate. These results demonstrate that accurate assessment of climate change impacts and development of effective adaptation and mitigation strategies must account for local water management practices. (letter)

  11. Do global change experiments overestimate impacts on terrestrial ecosystems?

    DEFF Research Database (Denmark)

    Leuzinger, Sebastian; Luo, Yiqi; Beier, Claus

    2011-01-01

    In recent decades, many climate manipulation experiments have investigated biosphere responses to global change. These experiments typically examined effects of elevated atmospheric CO2, warming or drought (driver variables) on ecosystem processes such as the carbon and water cycle (response...... of the responses to decline with higher-order interactions, longer time periods and larger spatial scales. This means that on average, both positive and negative global change impacts on the biosphere might be dampened more than previously assumed....

  12. Structural Response of the Earth's Crust to an Extra-Terrestrial Source of Stress by Identifying its Characteristic Pattern

    Science.gov (United States)

    Dasgupta, B.

    2016-12-01

    The earth's crust is a geodynamic realm, which is constantly evolving. Due to its dynamic nature, the crust is constantly being subjected to remodelling. The earth's crustal response to stress is a result of isostatic compensation. The crust is also a living proof of yesteryears' dynamics. Extra-terrestrial agents of deformation refers to meteorites, asteroids etc. These are catastrophic events that influence a larger area (considering larger impact bodies). They effect the crust from outside, hence leave behind very specific structural signatures.Consider an extra-terrestrial object impacting the earth's crust. The problem can be broken down into 3 parts: Pre Impact (kinematics of the object and nature of surface of impact); Syn Impact (dissipation of energy and formation of crater); and Post Impact (structural response, geophysical anomalies and effect on biota)Upon impact, the projectile penetrates the earth's crust to a depth of twice its diameter. Shock waves generated due impact propagate in all possible directions. The reflected waves cause complete melting and vaporization of the impact body. At the same time, increased internal energy of the system melts the target rock. Depending on the thickness and density of crustal matter, its' interaction with the mantle is determined. Data collection from such impact sites is the first step towards its theoretical modeling. Integrating geophysical (seismic, magnetic), paleomagnetic, geochemical and geo-chronological data one can determine the kinematic parameters that governed the event. A working model that illustrates the crustal responses to extraterrestrial stress of extreme magnitude cannot be qualitative. Hence the most fundamental thing at this point is quantification of these parameters. The variables form a `mass-energy equation', a simple theorem in Classical Physics. This project is directed to give the equation its shape. The equation will be the foundation on which the simulation model will rest. Mass

  13. Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroids.

    Science.gov (United States)

    Saudan, Christophe; Baume, Norbert; Emery, Caroline; Strahm, Emmanuel; Saugy, Martial

    2008-06-10

    Tribulus terrestris is a nutritional supplement highly debated regarding its physiological and actual effects on the organism. The main claimed effect is an increase of testosterone anabolic and androgenic action through the activation of endogenous testosterone production. Even if this biological pathway is not entirely proven, T. terrestris is regularly used by athletes. Recently, the analysis of two female urine samples by GC/C/IRMS (gas chromatography/combustion/isotope-ratio-mass-spectrometry) conclusively revealed the administration of exogenous testosterone or its precursors, even if the testosterone glucuronide/epitestosterone glucuronide (T/E) ratio and steroid marker concentrations were below the cut-off values defined by World Anti-Doping Agency (WADA). To argue against this adverse analytical finding, the athletes recognized having used T. terrestris in their diet. In order to test this hypothesis, two female volunteers ingested 500 mg of T. terrestris, three times a day and for two consecutive days. All spot urines were collected during 48 h after the first intake. The (13)C/(12)C ratio of ketosteroids was determined by GC/C/IRMS, the T/E ratio and DHEA concentrations were measured by GC/MS and LH concentrations by radioimmunoassay. None of these parameters revealed a significant variation or increased above the WADA cut-off limits. Hence, the short-term treatment with T. terrestris showed no impact on the endogenous testosterone metabolism of the two subjects.

  14. Terrestrial aftermath of the Moon-forming impact.

    Science.gov (United States)

    Sleep, Norman H; Zahnle, Kevin J; Lupu, Roxana E

    2014-09-13

    Much of the Earth's mantle was melted in the Moon-forming impact. Gases that were not partially soluble in the melt, such as water and CO2, formed a thick, deep atmosphere surrounding the post-impact Earth. This atmosphere was opaque to thermal radiation, allowing heat to escape to space only at the runaway greenhouse threshold of approximately 100 W m(-2). The duration of this runaway greenhouse stage was limited to approximately 10 Myr by the internal energy and tidal heating, ending with a partially crystalline uppermost mantle and a solid deep mantle. At this point, the crust was able to cool efficiently and solidified at the surface. After the condensation of the water ocean, approximately 100 bar of CO2 remained in the atmosphere, creating a solar-heated greenhouse, while the surface cooled to approximately 500 K. Almost all this CO2 had to be sequestered by subduction into the mantle by 3.8 Ga, when the geological record indicates the presence of life and hence a habitable environment. The deep CO2 sequestration into the mantle could be explained by a rapid subduction of the old oceanic crust, such that the top of the crust would remain cold and retain its CO2. Kinematically, these episodes would be required to have both fast subduction (and hence seafloor spreading) and old crust. Hadean oceanic crust that formed from hot mantle would have been thicker than modern crust, and therefore only old crust underlain by cool mantle lithosphere could subduct. Once subduction started, the basaltic crust would turn into dense eclogite, increasing the rate of subduction. The rapid subduction would stop when the young partially frozen crust from the rapidly spreading ridge entered the subduction zone. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  15. Accuracy assessment of modeling architectural structures and details using terrestrial laser scanning

    Directory of Open Access Journals (Sweden)

    M. Kedzierski

    2015-08-01

    Full Text Available One of the most important aspects when performing architectural documentation of cultural heritage structures is the accuracy of both the data and the products which are generated from these data: documentation in the form of 3D models or vector drawings. The paper describes an assessment of the accuracy of modelling data acquired using a terrestrial phase scanner in relation to the density of a point cloud representing the surface of different types of construction materials typical for cultural heritage structures. This analysis includes the impact of the scanning geometry: the incidence angle of the laser beam and the scanning distance. For the purposes of this research, a test field consisting of samples of different types of construction materials (brick, wood, plastic, plaster, a ceramic tile, sheet metal was built. The study involved conducting measurements at different angles and from a range of distances for chosen scanning densities. Data, acquired in the form of point clouds, were then filtered and modelled. An accuracy assessment of the 3D model was conducted by fitting it with the point cloud. The reflection intensity of each type of material was also analyzed, trying to determine which construction materials have the highest reflectance coefficients, and which have the lowest reflection coefficients, and in turn how this variable changes for different scanning parameters. Additionally measurements were taken of a fragment of a building in order to compare the results obtained in laboratory conditions, with those taken in field conditions.

  16. Characterization of inclusions in terrestrial impact formed zircon: Constraining the formation conditions of Hadean zircon from Jack Hills, Western Australia

    Science.gov (United States)

    Faltys, J. P.; Wielicki, M. M.; Sizemore, T. M.

    2017-12-01

    Due to the discovery and subsequent geochemical analysis of Hadean terrestrial material (e.g. detrital zircon from Jack Hills, Western Australia), a dramatic paradigm shift has occurred in the hypothesized near surface conditions of the first 500 million years of Earth's evolution. From a hellish setting riddled with impactors and not fit for life to a much milder environment that may have been uniquely suitable for the origin of life. Geochemical analyses of these ancient materials have been used to suggest the presence of water at or near the surface as well as the existence of continental crust during the Hadean, both of which have been suggested as necessary for the origin of life. However, the intensity of extraterrestrial bombardment during the Hadean and the effects of such events on the origin of life remains poorly understood. Clearly, as evidenced by Phanerozoic impact events, extraterrestrial impactors have the potential to dramatically effect the environment, particularly the biosphere. Early Earth likely experienced multiple large impact events, as evidenced by the lunar record, however whether those impacts were sufficient to frustrate the origin of life remains an open question. Although multiple lines of evidence, including the inclusion population, suggest the formation of Hadean zircon from Jack Hills as crystallizing in an under-thrust environment from S-type magmas, a recent study has suggested their formation in an impact melt environment analogous to a portion of the Sudbury Igneous Complex at the Sudbury impact structure. To determine between these two formation scenarios we have under-taken an inclusion study of terrestrial impact formed zircon from four of the largest terrestrial impact structures (Sudbury, Canada; Manicouagan, Canada; Vredefort, South Africa; Morokweng, South Africa), to compare to the vast inclusion dataset that exists for Jack Hills zircon. Preliminary data suggests a different inclusion population, from Hadean zircon

  17. Phylogeography and spatial structure of the lowland tapir (Tapirus terrestris, Perissodactyla: Tapiridae) in South America.

    Science.gov (United States)

    Ruiz-García, Manuel; Vásquez, Catalina; Sandoval, Sergio; Kaston, Franz; Luengas-Villamil, Kelly; Shostell, Joseph Mark

    2016-07-01

    We sequenced the mitochondrial cytochrome b gene of 141 lowland tapirs (Tapirus terrestris) - representing the largest geographical distribution sample of this species studied across of South America to date. We compare our new data regard to two previous works on population structure and molecular systematics of T. terrestris. Our data agree with the Thoisy et al.'s work in (1) the Northern Western Amazon basin was the area with the highest gene diversity levels in T. terrestris, being probably the area of initial diversification; (2) there was no clear association between haplogroups and specific geographical areas; (3) there were clear population decreases during the last glacial maximum for the different haplogroups detected, followed by population expansions during the Holocene; and (4) our temporal splits among different T. terrestris haplogroups coincided with the first molecular clock approach carried out by these authors (fossil calibration). Nevertheless, our study disagreed regard to other aspects of the Thoisy et al.'s claims: (1) meanwhile, they detected four relevant clades in their data, we put forward six different relevant clades; (2) the Amazon River was not a strong barrier for haplotype dispersion in T. terrestris; and (3) we found reciprocal monophyly between T. terrestris and T. pinchaque. Additionally, we sequenced 42 individuals (T. terrestris, T. pinchaque, T. bairdii, and the alleged "new species", T. kabomani) for three concatenated mitochondrial genes (Cyt-b, COI, and COII) agreeing quite well with the view of Voss et al., and against of the claims of Cozzuol et al. Tapirus kabomani should be not considered as a full species with the results obtained throughout the mitochondrial sequences.

  18. Understanding and Projecting Climate and Human Impacts on Terrestrial-Coastal Carbon and Nutrient Fluxes

    Science.gov (United States)

    Lohrenz, S. E.; Cai, W. J.; Tian, H.; He, R.; Fennel, K.

    2017-12-01

    Changing climate and land use practices have the potential to dramatically alter coupled hydrologic-biogeochemical processes and associated movement of water, carbon and nutrients through various terrestrial reservoirs into rivers, estuaries, and coastal ocean waters. Consequences of climate- and land use-related changes will be particularly evident in large river basins and their associated coastal outflow regions. Here, we describe a NASA Carbon Monitoring System project that employs an integrated suite of models in conjunction with remotely sensed as well as targeted in situ observations with the objectives of describing processes controlling fluxes on land and their coupling to riverine, estuarine and ocean ecosystems. The nature of our approach, coupling models of terrestrial and ocean ecosystem dynamics and associated carbon processes, allows for assessment of how societal and human-related land use, land use change and forestry and climate-related change affect terrestrial carbon transport as well as export of materials through watersheds to the coastal margins. Our objectives include the following: 1) Provide representation of carbon processes in the terrestrial ecosystem to understand how changes in land use and climatic conditions influence the export of materials to the coastal ocean, 2) Couple the terrestrial exports of carbon, nutrients and freshwater to a coastal biogeochemical model and examine how different climate and land use scenarios influence fluxes across the land-ocean interface, and 3) Project future changes under different scenarios of climate and human impact, and support user needs related to carbon management and other activities (e.g., water quality, hypoxia, ocean acidification). This research is providing information that will contribute to determining an overall carbon balance in North America as well as describing and predicting how human- and climate-related changes impact coastal water quality including possible effects of coastal

  19. The impacts of past climate change on terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Bradshaw, R.H.W.; Anderson, N.J.

    2001-01-01

    The last two million years of global history have been dominated by the impacts of rapid climate change. This influence is not immediately obvious to most biologists whose observations rarely extend beyond a period of a few years, but becomes apparent when interpreting long-term data sets whether they be population studies or palaeoecological data. It is appropriate therefore to consider how terrestrial and aquatic ecosystems have responded to climate change during the Quaternary when speculating about response to future climatic developments. In this chapter we discuss and illustrate the complex interactions between climate and anthropogenic influence on terrestrial and aquatic ecosystems during the Holocene. Climate influences ecosystems both directly (e.g. physiological responses or lake thermal stratification) and indirectly (e.g. via fire frequency or catchment hydrology). Lake sediments can be used to study both past climatic change directly and the effects of past climatic variability. In this chapter we present summary examples of the influence of past climate change on terrestrial and aquatic ecosystems as well showing how lake sediment records can provide proxy records of past climate change. The geological record from the last 18 000 years documents large changes in terrestrial and aquatic ecosystems that are primarily driven by climatic change, but are modified by internal ecosystem processes. These changes are comparable in magnitude and rapidity to those predicted for the near future. Species at their distributional limits are particularly sensitive to climate change and contractions of range can be sudden in response to extreme climatic events such as the storm of December 1999 that damaged Picea trees far more than tree species that lay within their natural range limits. Palaeoecological records provide compelling evidence for direct climate forcing of aquatic and terrestrial ecosystems but importantly also permit comparative analyses of impacts

  20. The impact of small terrestrial mammals on beech (Fagus sylvatica plantations in spruce monoculture

    Directory of Open Access Journals (Sweden)

    Luboš Purchart

    2007-01-01

    Full Text Available Little is known about the impact of small terrestrial mammals on forest regeneration as yet. In order to determine the level of small rodent impact on artificial forest regeneration, 508 saplings have been researched in a spruce monoculture in the Drahany Uplands. With the objective to hone the interpretation of the data, small terrestrial rodents were trapped to help determine species spectrum. The occurrence of Apodemus flavicollis, Clethrionomys glareolus and Sorex araneus was verified. In 52 cases damage to the trunk caused by small rodents was monitored (10.1% of all saplings. 8 specimens (1.6% had their branches nibbled and 9 saplings (1.8% had tips of branches or trunk tops browsed. Browsing by Lepus europaeus – 423 (83.3% of all damaged specimens was significant.

  1. Terrestrial catastrophe caused by cometary impact at the end of Cretaceous

    Science.gov (United States)

    Hsü, Kenneth J.

    1980-05-01

    Evidence is presented indicating that the extinction, at the end of the Cretaceous, of large terrestrial animals was caused by atmospheric heating during a cometary impact and that the extinction of calcareous marine plankton was a consequence of poisoning by cyanide released by the fallen comet and of a catastrophic rise in calcite-compensation depth in the oceans after the detoxification of the cyanide.

  2. Waveform- and Terrestrial Lidar Assessment of the Usual (Structural) Suspects in a Forest Canopy

    Science.gov (United States)

    van Aardt, J. A.; Romanczyk, P.; Kelbe, D.; van Leeuwen, M.; Cawse-Nicholson, K.; Gough, C. M.; Kampe, T. U.

    2015-12-01

    Forest inventory has evolved from standard stem diameter-height relationships, to coarse canopy metrics, to more involved ecologically-meaningful variables, such as leaf area index (LAI) and even canopy radiative transfer as a function of canopy gaps, leaf clumping, and leaf angle distributions. Accurate and precise measurement of the latter set of variables presents a challenge to the ecological and modeling communities; however, relatively novel remote sensing modalities, e.g., waveform lidar (wlidar) and terrestrial lidar systems (TLS), have the potential to adress this challenge. Research teams at Rochester Institute of Technology (RIT) and the Virginia Commonwealth University (VCU) have been collaborating with the National Ecological Observation Network (NEON) to assess vegetation canopy structure and variation at the University of Michigan Biological Research Station and the NEON Northeast domain (Harvard Forest, MA). Airborne small-footprint wlidar data, in-situ TLS data, and first-principles, physics-based simulation tools are being used to study (i) the impact of vegetation canopy geometric elements on wlidar signals (twigs and petioles have been deemed negligible), (ii) the analysis of airborne wlidar data for top-down assessment of canopy metrics such as LAI, and (iii) our ability to extract "bottom-up" canopy structure from TLS using scans registered to each other using a novel marker-free registration approach (e.g., basal area: R2=0.82, RMSE=7.43 m2/ha). Such studies indicate that we can potentially assess radiative transfer through vegetation canopies remotely using a vertically-stratified approach with wlidar, and augment such an approach via rapid-scan TLS technology to gain a better understanding of fine-scale variation in canopy structure. This in turn is key to quantifying and modeling radiative transfer based on understanding of forest canopy structural change as a function of ecosystem development, climate, and anthropogenic drivers.

  3. Development of new historical global Nitrogen fertilizer map and the evaluation of their impacts on terrestrial N cycling and the evaluation of their impacts on terrestrial N cycling

    Science.gov (United States)

    Nishina, K.; Ito, A.; Hayashi, S.

    2015-12-01

    The use of synthetic nitrogen fertilizer was rapidly growing up after the birth of Haber-Bosch process in the early 20th century. The recent N loading derived from these sources on terrestrial ecosystems was estimated 2 times higher than biogenic N fixation in terrestrial ecosystems (Gruber et al., 2009). However, there are still large uncertainties in cumulative N impacts on terrestrial impact at global scale. In this study, to assess historical N impacts at global scale, we made a new global N fertilizer input map, which was a spatial-temporal explicit map (during 1960-2010) and considered the fraction of NH4+ and NO3- in the N fertilizer inputs. With the developed N fertilizer map, we evaluated historical N20 cycling changes by land-use changes and N depositions in N cycling using ecosystem model 'VISIT'. Prior to the downscaling processes for global N fertilizer map, we applied the statistical data imputation to FAOSTAT data due to there existing many missing data especially in developing countries. For the data imputation, we used multiple data imputation method proposed by Honaker & King (2010). The statistics of various types of synthetic fertilizer consumption are available in FAOSTAT, which can be sorted by the content of NH4+ and NO3-, respectively. To downscaling the country by country N fertilizer consumptions data to the 0.5˚x 0.5˚ grid-based map, we used historical land-use map in Earthstat (Rumankutty et al., 1999). Before the assignment of N fertilizer in each grid, we weighted the double cropping regions to be more N fertilizer input on to these regions. Using M3-Crops Data (Monfreda et al., 2008), we picked up the dominant cropping species in each grid cell. After that, we used Crop Calendar in SAGE dataset (Sacks et al., 2010) and determined schedule of N fertilizer input in each grid cell using dominant crop calendar. Base fertilizer was set to be 7 days before transplanting and second fertilizer to be 30 days after base fertilizer application

  4. Evidence for and implications of an Early Archean terrestrial impact record

    International Nuclear Information System (INIS)

    Lowe, D.R.; Byerly, G.R.

    1988-01-01

    Early Archean, 3.5 to 3.2 Ga, greenstone sequences in South Africa and Western Australia contain a well-preserved record of early terrestrial meteorite impacts. The main impact-produced deposits are layers, 10 cm to over 1 m thick, composed largely of sand-sized spherules, 0.1 to 4 mm in diameter. The beds studied to date show an assemblage of features indicating formation by the fall of debris from impact-generated ejecta clouds. Some presented data effectively rule out normal magmatic or sedimentary processes in the origin of these units and provide substantial support for an origin by large impacts on the early earth. The presence of at least four, remarkably thick, nearly pure spherule layers suggests that smaller-scale impact deposits may be even more abundant in these sequences. The existence of a well-preserved Archean terrestrial impact record suggests that a direct source of evidence is available regarding a number of important aspects of early earth history

  5. Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake

    Science.gov (United States)

    Oschlies, A.

    2009-08-01

    The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. The smaller efficiency of the oceanic carbon uptake under an interactive atmosphere is due to the back flux of CO2 that occurs when atmospheric CO2 is reduced. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively, for pCO2 sensitivities of the terrestrial carbon storage in the middle range of the C4MIP models (Friedlingstein et al., 2006). For such sensitivities, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization originates, on timescales longer than decades, not from the atmosphere

  6. Graphene ultracapacitors: structural impacts.

    Science.gov (United States)

    Song, Weixin; Ji, Xiaobo; Deng, Wentao; Chen, Qiyuan; Shen, Chen; Banks, Craig E

    2013-04-07

    The structural effects of graphene on the electrochemical properties of graphene-based ultracapacitors are investigated for the first time, where the competitive impacts resulting from the edge content, specific surface area, edge/basal defects, oxygen-containing groups and metal oxides/surfactant impurities are taken into consideration, demonstrating that not one element, but all are responsible for the final behavior of graphene-based ultracapacitors. This work will be of wide importance to research producing graphene-based energy storage/generation devices.

  7. Re-plumbing the Terrestrial Hydrosphere: Scope and Impact of Major Inter-basin Water Transfers

    Science.gov (United States)

    Shikhmacheva, K. V.; Vorosmarty, C. J.; Fekete, B. M.; Afshari, S.; Aside, B.; Chibisova, Y.; Dopson, I.; Link, H.; Mouden, A.

    2013-12-01

    The availability of water has become one of the main concerns in modern history and it is an important policymaking strategy. Increasing population, agricultural intensification, rapid urbanization, industrial expansion and environmental changes increase water demand on region and global scales. Inter-Basin Water Transfer (IBWT) is an important element of satisfying immediate water requirements. The complex engineering structures divert water flow between watersheds, thus ';re-plumbing' terrestrial hydrosphere. We report here an analysis of inter-basin water transfer for the Northeast region, which is a part of an NSF funded project entitled 'The NorthEast Regional Earth System Model (NE-RESM).' In addition, this work is also a part of a global IBWT study. First, we present the IBWT geo-referenced assembled data set, derived from from maps, published documents and online resources. The information in the data base was classified by project name, diverted volume, source location, usage, status of construction, transport distance and purpose. The key feature of the dataset is geo-location of the projects, that allows further analysis of the hydrologic impact of each of the projects as well as their collective significance. Upon completion of the data-collection phase, the inputs were verified using RiverGIS and ArcGIS software. In addition, we investigated some key measures of IBWT distortion of regional-scale hydrology as well as their socio-economic impacts across the Northeast region. We calculated several indicators to assess these impacts, for example the donor-to-recipient basin flow ratio, which represents the 'gain' and 'loss' of water relative to the natural flow on a basin scale. Elements of the regional IBWT data base will be incorporated into the regional-scale Water Balance Model (WBM), and linked to the operation of reservoirs and dams. While focused on the Northeastern U.S., we believe that this data, its testing and applications will yield broad use

  8. Impact of an asteroid or comet in the ocean and extinction of terrestrial life

    International Nuclear Information System (INIS)

    Ahrens, T.J.; O'Keefe, J.D.

    1983-01-01

    Finite difference calculations describing the impact mechanics associated with a 10 to 30 km diameter silicate or water object impacting a 5 km deep ocean overlying a silicate solid planet at 30 km/sec demonstrate that from 12 to 15% of the bolide energy resides in the water. In the gravity field of the earth some 10 to 30 times the impactor mass of water is launched on trajectories which would take it to altitudes of 10 km or higher. This ejecta launched on trajectories which can achieve stratospheric heights is 10 1 to 10 2 projectile masses, similar to that resulting from impact of objects on an ocean-free silicate half-space (continent). Ejecta composed of impactor material, launched on trajectories which would carry it to stratospheric heights, matches the fraction (10 -2 to 10 -1 ) of bolide (extraterrestrial) material found in the platinum-metal-rich Cretaceous-Tertiary and Eocene-Oligocene boundary layers. Oceanic impact results in giant tsunamis initially having amplitudes of approx. 4 km, representing the solitary waterwave stability limit in the deep ocean, and containing 10 -2 to 10 -1 of the energy of the impact. Using the constraint of no observed turbidities in marine sediments in the Cretaceous-Tertiary and Eocene-Oligocene boundary materials (calculated maximum water-sediment interface particle velocity approx. 10 0 m/sec) implies a maximum impactor energy of approx. 10 28 to approx. 10 29 erg corresponding to a maximum diameter for a silicate impactor of approx. 2 km (at 11 km/sec). Minimal global tsunami run-up heights on the continents corresponding to impacts of this energy are 300-400 m. We speculate that such waves would inundate all low altitude continental areas. As a result, the terrestrial animal food chain would be seriously perturbed, which could have caused extinction of large terrestrial animals

  9. Late Impacts and the Origins of the Atmospheres on the Terrestrial Planets

    Science.gov (United States)

    Mukhopadhyay, S.; Stewart, S. T.; Lock, S. J.; Parai, R.; Tucker, J. M.

    2014-12-01

    Models for the origin of terrestrial atmospheres typically require an intricate sequence of events, including hydrodynamic escape, outgassing of mantle volatiles and late delivery. Here we discuss the origin of the atmospheres on the terrestrial planets in light of new ideas about the formation of the Moon, giant impact induced atmospheric loss and recent noble gas measurements. Our new measurements indicate that noble gases in the Earth's atmosphere cannot be derived from any combination of fractionation of a nebular-derived atmosphere followed by outgassing of deep or shallow mantle volatiles. While Ne in the mantle retains a nebular component, the present-day atmosphere has no memory of nebular gases. Rather, atmospheric noble gases have a close affinity to chondrites. On the other hand, Venus's atmosphere has 20 and 70 times higher abundance of 20Ne and 36Ar, respectively, and a 20Ne/22Ne ratio closer to the solar value than Earth's atmosphere. While the present atmosphere of Mars is significantly fractionated in the lighter noble gases due to long term atmospheric escape, the Kr isotopic ratios in Martian atmosphere are identical to solar. Thus, while Earth's atmosphere has no memory of accretion of nebular gases, atmospheres on both Venus and Mars preserve at least a component of nebular gases. To explain the above observations, we propose that a common set of processes operated on the terrestrial planets, and that their subsequent evolutionary divergence is simply explained by planetary size and the stochastic nature of giant impacts. We present geochemical observations and simulations of giant impacts to show that most of Earth's mantle was degassed and the outgassed volatiles were largely lost during the final sequence of giant impacts onto Earth. Earth's noble gases were therefore dominantly derived from late-accreting planetesimals. In contrast, Venus did not suffer substantial atmospheric loss by a late giant impact and retains a higher abundance of

  10. Characterizing Tropical Forest Structure using Field-based Measurements and a Terrestrial Lidar

    Science.gov (United States)

    Palace, M. W.; Sullivan, F.; Ducey, M. J.; Herrick, C.

    2015-12-01

    Forest structure comprises numerous quantifiable components of forest biometric characteristics, one of which is tree architecture. This structural component is important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar). This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS) system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs) and calculated a series of parameters including entropy, FFT, number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using multiple linear regressions, all of which converged on statistically significant relationships with the strongest relationship being for mean crown depth (r2 = 0.87, p information on tropical forest structure.

  11. Dynamical Origin and Terrestrial Impact Flux of Large Near-Earth Asteroids

    Science.gov (United States)

    Nesvorný, David; Roig, Fernando

    2018-01-01

    Dynamical models of the asteroid delivery from the main belt suggest that the current impact flux of diameter D> 10 km asteroids on the Earth is ≃0.5–1 Gyr‑1. Studies of the Near-Earth Asteroid (NEA) population find a much higher flux, with ≃ 7 D> 10 km asteroid impacts per Gyr. Here we show that this problem is rooted in the application of impact probability of small NEAs (≃1.5 Gyr‑1 per object), whose population is well characterized, to large NEAs. In reality, large NEAs evolve from the main belt by different escape routes, have a different orbital distribution, and lower impact probabilities (0.8 ± 0.3 Gyr‑1 per object) than small NEAs. In addition, we find that the current population of two D> 10 km NEAs (Ganymed and Eros) is a slight fluctuation over the long-term average of 1.1+/- 0.5 D> 10 km NEAs in a steady state. These results have important implications for our understanding of the occurrence of the K/T-scale impacts on the terrestrial worlds.

  12. Concrete structures under projectile impact

    CERN Document Server

    Fang, Qin

    2017-01-01

    In this book, the authors present their theoretical, experimental and numerical investigations into concrete structures subjected to projectile and aircraft impacts in recent years. Innovative approaches to analyze the rigid, mass abrasive and eroding projectile penetration and perforation are proposed. Damage and failure analyses of nuclear power plant containments impacted by large commercial aircrafts are numerically and experimentally analyzed. Ultra-high performance concrete materials and structures against the projectile impact are developed and their capacities of resisting projectile impact are evaluated. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

  13. Root structural and functional dynamics in terrestrial biosphere models--evaluation and recommendations.

    Science.gov (United States)

    Warren, Jeffrey M; Hanson, Paul J; Iversen, Colleen M; Kumar, Jitendra; Walker, Anthony P; Wullschleger, Stan D

    2015-01-01

    There is wide breadth of root function within ecosystems that should be considered when modeling the terrestrial biosphere. Root structure and function are closely associated with control of plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils, and control of biogeochemical cycles through interactions within the rhizosphere. Root function is extremely dynamic and dependent on internal plant signals, root traits and morphology, and the physical, chemical and biotic soil environment. While plant roots have significant structural and functional plasticity to changing environmental conditions, their dynamics are noticeably absent from the land component of process-based Earth system models used to simulate global biogeochemical cycling. Their dynamic representation in large-scale models should improve model veracity. Here, we describe current root inclusion in models across scales, ranging from mechanistic processes of single roots to parameterized root processes operating at the landscape scale. With this foundation we discuss how existing and future root functional knowledge, new data compilation efforts, and novel modeling platforms can be leveraged to enhance root functionality in large-scale terrestrial biosphere models by improving parameterization within models, and introducing new components such as dynamic root distribution and root functional traits linked to resource extraction. No claim to original US Government works. New Phytologist © 2014 New Phytologist Trust.

  14. Evaluation of Terrestrial Laser Scanner Accuracy in the Control of Hydrotechnical Structures

    Science.gov (United States)

    Muszyński, Zbigniew; Rybak, Jarosław

    2017-12-01

    In many cases of monitoring or load testing of hydrotechnical structures, the measurement results obtained from dial gauges may be affected by random or systematic errors resulting from the instability of the reference beam. For example, the measurement of wall displacement or pile settlement may be increased (or decreased) by displacements of the reference beam due to ground movement. The application of surveying methods such as high-precision levelling, motorized tacheometry or even terrestrial laser scanning makes it possible to provide an independent reference measurement free from systematic errors. It is very important in the case of walls and piles embedded in the rivers, where the construction of reference structure is even more difficult than usually. Construction of an independent reference system is also complicated when horizontal testing of sheet piles or diaphragm walls are considered. In this case, any underestimation of the horizontal displacement of an anchored or strutted construction leads to an understated value of the strut's load. These measurements are even more important during modernization works and repairs of the hydrotechnical structures. The purpose of this paper is to discuss the possibilities of using modern measurement methods for monitoring of horizontal displacements of an excavation wall. The methods under scrutiny (motorized tacheometry and terrestrial laser scanning) have been compared to classical techniques and described in the context of their practical use on the example hydrotechnical structure. This structure was a temporary cofferdam made from sheet pile wall. The research continuously conducted at Wroclaw University of Science and Technology made it possible to collect and summarize measurement results and practical experience. This paper identifies advantages and disadvantages of both analysed methods and presents a comparison of obtained measurement results of horizontal displacements. In conclusion, some

  15. Cernavoda NPP impact study on terrestrial and aquatic biota. Preliminary results

    International Nuclear Information System (INIS)

    Bobric, Elena; Bucur, Cristina; Popescu, Ion; Simionov, Vasile; Titescu, Gheorghe; Varlam, Carmen

    2010-01-01

    Recently, the awareness of the vulnerability of the environment has increased and the need to protect it against industrial pollutants has been recognized. The concept of sustainable development, requires new and developing international policies for environmental protection. See 'Protection of the environment from the effects of ionizing radiation' IAEA-TECDOC-1091, International Atomic Energy Agency, Vienna. As it is recommended in 'Cernavoda Unit No. 2 NPP Environmental Impact Assessment CES-03702-IAD-006', it is Cernavoda NPP responsibility to conduct an Ecological Risk Assessment study, mainly to assess the impact of nuclear power plant operation on terrestrial and aquatic biota. Long records from normal operation of Cernavoda Unit 1, wind pattern, meteorological conditions, and source terms data were used to evaluate areas of interest for environmental impact, conducting to a circle of 20 km radius around mentioned nuclear objective. The screening campaign established tritium level (because Cernavoda NPP is a CANDU type reactor, and tritium is the most important radioisotope evacuated in the environment) in air, water, soil and vegetation, focusing the interest area on particular ecosystem. Using these primary data it was evaluated which are the monitored ecological receptors and which are the measurement endpoints.This paper presents the Ecological Risk Assessment at Cernavoda NPP technical requirements, and the preliminary results of evaluating criteria for representative ecosystem components at Cernavoda NPP. (authors)

  16. Evaluating aggregate terrestrial impacts of road construction projects for advanced regional mitigation.

    Science.gov (United States)

    Thorne, James H; Girvetz, Evan H; McCoy, Michael C

    2009-05-01

    This study presents a GIS-based database framework used to assess aggregate terrestrial habitat impacts from multiple highway construction projects in California, USA. Transportation planners need such impact assessment tools to effectively address additive biological mitigation obligations. Such assessments can reduce costly delays due to protracted environmental review. This project incorporated the best available statewide natural resource data into early project planning and preliminary environmental assessments for single and multiple highway construction projects, and provides an assessment of the 10-year state-wide mitigation obligations for the California Department of Transportation. Incorporation of these assessments will facilitate early and more strategic identification of mitigation opportunities, for single-project and regional mitigation efforts. The data architecture format uses eight spatial scales: six nested watersheds, counties, and transportation planning districts, which were intersected. This resulted in 8058 map planning units statewide, which were used to summarize all subsequent analyses. Range maps and georeferenced locations of federally and state-listed plants and animals and a 55-class landcover map were spatially intersected with the planning units and the buffered spatial footprint of 967 funded projects. Projected impacts were summarized and output to the database. Queries written in the database can sum expected impacts and provide summaries by individual construction project, or by watershed, county, transportation district or highway. The data architecture allows easy incorporation of new information and results in a tool usable without GIS by a wide variety of agency biologists and planners. The data architecture format would be useful for other types of regional planning.

  17. Evaluating Aggregate Terrestrial Impacts of Road Construction Projects for Advanced Regional Mitigation

    Science.gov (United States)

    Thorne, James H.; Girvetz, Evan H.; McCoy, Michael C.

    2009-05-01

    This study presents a GIS-based database framework used to assess aggregate terrestrial habitat impacts from multiple highway construction projects in California, USA. Transportation planners need such impact assessment tools to effectively address additive biological mitigation obligations. Such assessments can reduce costly delays due to protracted environmental review. This project incorporated the best available statewide natural resource data into early project planning and preliminary environmental assessments for single and multiple highway construction projects, and provides an assessment of the 10-year state-wide mitigation obligations for the California Department of Transportation. Incorporation of these assessments will facilitate early and more strategic identification of mitigation opportunities, for single-project and regional mitigation efforts. The data architecture format uses eight spatial scales: six nested watersheds, counties, and transportation planning districts, which were intersected. This resulted in 8058 map planning units statewide, which were used to summarize all subsequent analyses. Range maps and georeferenced locations of federally and state-listed plants and animals and a 55-class landcover map were spatially intersected with the planning units and the buffered spatial footprint of 967 funded projects. Projected impacts were summarized and output to the database. Queries written in the database can sum expected impacts and provide summaries by individual construction project, or by watershed, county, transportation district or highway. The data architecture allows easy incorporation of new information and results in a tool usable without GIS by a wide variety of agency biologists and planners. The data architecture format would be useful for other types of regional planning.

  18. Actual versus predicted impacts of three ethanol plants on aquatic and terrestrial resources

    International Nuclear Information System (INIS)

    Eddlemon, G.K.; Webb, J.W.; Hunsaker, D.B. Jr.; Miller, R.L.

    1993-01-01

    To help reduce US dependence on imported petroleum, Congress passed the Energy Security Act of 1980 (public Law 96-294). This legislation authorized the US Department of Energy (DOE) to promote expansion of the fuel alcohol industry through, among other measures, its Alcohol Fuels Loan Guarantee Program. Under this program, selected proposals for the conversion of plant biomass into fuel-grade ethanol would be granted loan guarantees. of 57 applications submitted for loan guarantees to build and operate ethanol fuel projects under this program, 11 were considered by DOE to have the greatest potential for satisfying DOE's requirements and goals. In accordance with the National Environmental Policy Act (NEPA), DOE evaluated the potential impacts of proceeding with the Loan Guarantee Program in a programmatic environmental assessment (DOE 1981) that resulted in a finding of no significant impact (FANCY) (47 Federal Register 34, p. 7483). The following year, DOE conducted site-specific environmental assessments (EAs) for 10 of the proposed projects. These F-As predicted no significant environmental impacts from these projects. Eventually, three ethanol fuel projects received loan guarantees and were actually built: the Tennol Energy Company (Tennol; DOE 1982a) facility near Jasper in southeastern Tennessee; the Agrifuels Refining Corporation (Agrifuels; DOE 1985) facility near New Liberia in southern Louisiana; and the New Energy Company of Indiana (NECI; DOE 1982b) facility in South Bend, Indiana. As part of a larger retrospective examination of a wide range of environmental effects of ethanol fuel plants, we compared the actual effects of the three completed plants on aquatic and terrestrial resources with the effects predicted in the NEPA EAs several years earlier. A secondary purpose was to determine: Why were there differences, if any, between actual effects and predictions? How can assessments be improved and impacts reduced?

  19. TURBULENCE-GENERATED PROTON-SCALE STRUCTURES IN THE TERRESTRIAL MAGNETOSHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Vörös, Zoltán; Narita, Yasuhito [Space Research Institute, Austrian Academy of Sciences, Graz (Austria); Yordanova, Emiliya [Swedish Institute of Space Physics, Uppsala (Sweden); Echim, Marius M. [Belgian Institute for Space Aeronomy, Bruxelles (Belgium); Consolini, Giuseppe, E-mail: zoltan.voeroes@oeaw.ac.at [INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma (Italy)

    2016-03-01

    Recent results of numerical magnetohydrodynamic simulations suggest that in collisionless space plasmas, turbulence can spontaneously generate thin current sheets. These coherent structures can partially explain the intermittency and the non-homogenous distribution of localized plasma heating in turbulence. In this Letter, Cluster multi-point observations are used to investigate the distribution of magnetic field discontinuities and the associated small-scale current sheets in the terrestrial magnetosheath downstream of a quasi-parallel bow shock. It is shown experimentally, for the first time, that the strongest turbulence-generated current sheets occupy the long tails of probability distribution functions associated with extremal values of magnetic field partial derivatives. During the analyzed one-hour time interval, about a hundred strong discontinuities, possibly proton-scale current sheets, were observed.

  20. New perspectives on the ecology of tree structure and tree communities through terrestrial laser scanning.

    Science.gov (United States)

    Malhi, Yadvinder; Jackson, Tobias; Patrick Bentley, Lisa; Lau, Alvaro; Shenkin, Alexander; Herold, Martin; Calders, Kim; Bartholomeus, Harm; Disney, Mathias I

    2018-04-06

    Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do. Here we focus on the ecological challenges and benefits of understanding tree form, and highlight some advances related to capturing and describing tree shape that are becoming possible with the advent of TLS. We present examples of ongoing work that applies, or could potentially apply, new TLS measurements to better understand the constraints on optimization of tree form. Theories of resource distribution networks, such as metabolic scaling theory, can be tested and further refined. TLS can also provide new approaches to the scaling of woody surface area and crown area, and thereby better quantify the metabolism of trees. Finally, we demonstrate how we can develop a more mechanistic understanding of the effects of avoidance of wind risk on tree form and maximum size. Over the next few years, TLS promises to deliver both major empirical and conceptual advances in the quantitative understanding of trees and tree-dominated ecosystems, leading to advances in understanding the ecology of why trees and ecosystems look and grow the way they do.

  1. Comparison of metal toxic impacts between aquatic and terrestrial organisms: is the free ion concentration a sufficient descriptor?

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Larsen, Henrik Fred

    2011-01-01

    Characterization of metal toxic impacts in comparative risk assessment and life cycle impact assessment (LCIA) should take into account metal speciation and interactions with soil/water organic constituents, because these mechanisms control metal bioavailability and may influence their toxic...... that the free metal ion is an appropriate “general”descriptor of metal toxicity. Results for 128 laboratory tests on Daphnia magna exposed to copper ions (Cu2+) in water show that variation of several orders of magnitude are observed between the toxicity tests. These variations may be a result of the inability...... of magnitude difference occur for the extreme case of barley (Hordeum vulgare). Given the scarcity of terrestrial effect data compared to aquatic data, reliable and transparent, mechanistic-based predictions of terrestrial toxic impacts from aquatic effect data would be an important step ahead in the context...

  2. Terrestrial laser scanning to quantify above-ground biomass of structurally complex coastal wetland vegetation

    Science.gov (United States)

    Owers, Christopher J.; Rogers, Kerrylee; Woodroffe, Colin D.

    2018-05-01

    Above-ground biomass represents a small yet significant contributor to carbon storage in coastal wetlands. Despite this, above-ground biomass is often poorly quantified, particularly in areas where vegetation structure is complex. Traditional methods for providing accurate estimates involve harvesting vegetation to develop mangrove allometric equations and quantify saltmarsh biomass in quadrats. However broad scale application of these methods may not capture structural variability in vegetation resulting in a loss of detail and estimates with considerable uncertainty. Terrestrial laser scanning (TLS) collects high resolution three-dimensional point clouds capable of providing detailed structural morphology of vegetation. This study demonstrates that TLS is a suitable non-destructive method for estimating biomass of structurally complex coastal wetland vegetation. We compare volumetric models, 3-D surface reconstruction and rasterised volume, and point cloud elevation histogram modelling techniques to estimate biomass. Our results show that current volumetric modelling approaches for estimating TLS-derived biomass are comparable to traditional mangrove allometrics and saltmarsh harvesting. However, volumetric modelling approaches oversimplify vegetation structure by under-utilising the large amount of structural information provided by the point cloud. The point cloud elevation histogram model presented in this study, as an alternative to volumetric modelling, utilises all of the information within the point cloud, as opposed to sub-sampling based on specific criteria. This method is simple but highly effective for both mangrove (r2 = 0.95) and saltmarsh (r2 > 0.92) vegetation. Our results provide evidence that application of TLS in coastal wetlands is an effective non-destructive method to accurately quantify biomass for structurally complex vegetation.

  3. Future global SLR network evolution and its impact on the terrestrial reference frame

    Science.gov (United States)

    Kehm, Alexander; Bloßfeld, Mathis; Pavlis, Erricos C.; Seitz, Florian

    2018-06-01

    Satellite laser ranging (SLR) is an important technique that contributes to the determination of terrestrial geodetic reference frames, especially to the realization of the origin and the scale of global networks. One of the major limiting factors of SLR-derived reference frame realizations is the datum accuracy which significantly suffers from the current global SLR station distribution. In this paper, the impact of a potential future development of the SLR network on the estimated datum parameters is investigated. The current status of the SLR network is compared to a simulated potential future network featuring additional stations improving the global network geometry. In addition, possible technical advancements resulting in a higher amount of observations are taken into account as well. As a result, we find that the network improvement causes a decrease in the scatter of the network translation parameters of up to 24%, and up to 20% for the scale, whereas the technological improvement causes a reduction in the scatter of up to 27% for the translations and up to 49% for the scale. The Earth orientation parameters benefit by up to 15% from both effects.

  4. A high-precision 40Ar/39Ar age for the Nördlinger Ries impact crater, Germany, and implications for the accurate dating of terrestrial impact events

    Science.gov (United States)

    Schmieder, Martin; Kennedy, Trudi; Jourdan, Fred; Buchner, Elmar; Reimold, Wolf Uwe

    2018-01-01

    40Ar/39Ar dating of specimens of moldavite, the formation of which is linked to the Ries impact in southern Germany, with a latest-generation ARGUS VI multi-collector mass spectrometer yielded three fully concordant plateau ages with a weighted mean age of 14.808 ± 0.021 Ma (± 0.038 Ma including all external uncertainties; 2σ; MSWD = 0.40, P = 0.67). This new best-estimate age for the Nördlinger Ries is in general agreement with previous 40Ar/39Ar results for moldavites, but constitutes a significantly improved precision with respect to the formation age of the distal Ries-produced tektites. Separates of impact glass from proximal Ries ejecta (suevite glass from three different surface outcrops) and partially melted feldspar particles from impact melt rock of the SUBO 18 Enkingen drill core failed to produce meaningful ages. These glasses show evidence for excess 40Ar introduction, which may have been incurred during interaction with hydrothermal fluids. Only partially reset 40Ar/39Ar ages could be determined for the feldspathic melt separates from the Enkingen core. The new 40Ar/39Ar results for the Ries impact structure constrain the duration of crater cooling, during the prevailing hydrothermal activity, to locally at least ∼60 kyr. With respect to the dating of terrestrial impact events, this paper briefly discusses a number of potential issues and effects that may be the cause for seemingly precise, but on a kyr-scale inaccurate, impact ages.

  5. Evaluation of Terrestrial Laser Scanner Accuracy in the Control of Hydrotechnical Structures

    Directory of Open Access Journals (Sweden)

    Muszyński Zbigniew

    2017-12-01

    Full Text Available In many cases of monitoring or load testing of hydrotechnical structures, the measurement results obtained from dial gauges may be affected by random or systematic errors resulting from the instability of the reference beam. For example, the measurement of wall displacement or pile settlement may be increased (or decreased by displacements of the reference beam due to ground movement. The application of surveying methods such as high-precision levelling, motorized tacheometry or even terrestrial laser scanning makes it possible to provide an independent reference measurement free from systematic errors. It is very important in the case of walls and piles embedded in the rivers, where the construction of reference structure is even more difficult than usually. Construction of an independent reference system is also complicated when horizontal testing of sheet piles or diaphragm walls are considered. In this case, any underestimation of the horizontal displacement of an anchored or strutted construction leads to an understated value of the strut’s load. These measurements are even more important during modernization works and repairs of the hydrotechnical structures.

  6. Leg tendon glands in male bumblebees ( Bombus terrestris): structure, secretion chemistry, and possible functions

    Science.gov (United States)

    Jarau, Stefan; Žáček, Petr; Šobotník, Jan; Vrkoslav, Vladimír; Hadravová, Romana; Coppée, Audrey; Vašíčková, Soňa; Jiroš, Pavel; Valterová, Irena

    2012-12-01

    Among the large number of exocrine glands described in bees, the tarsal glands were thought to be the source of footprint scent marks. However, recent studies showed that the compounds used for marking by stingless bees are secreted by leg tendon instead of tarsal glands. Here, we report on the structure of leg tendon glands in males of Bombus terrestris, together with a description of the chemical composition of their secretions and respective changes of both during the males' lives. The ultrastructure of leg tendon glands shows that the secretory cells are located in three independent regions, separated from each other by unmodified epidermal cells: in the femur, tibia, and basitarsus. Due to the common site of secretion release, the organ is considered a single secretory gland. The secretion of the leg tendon glands of B. terrestris males differs in its composition from those of workers and queens, in particular by (1) having larger proportions of compounds with longer chain lengths, which we identified as wax esters; and (2) by the lack of certain hydrocarbons (especially long chain dienes). Other differences consist in the distribution of double bond positions in the unsaturated hydrocarbons that are predominantly located at position 9 in males but distributed at seven to nine different positions in the female castes. Double bond positions may change chemical and physical properties of a molecule, which can be recognized by the insects and, thus, may serve to convey specific information. The function of male-specific compounds identified from their tendon glands remains elusive, but several possibilities are discussed.

  7. Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

    Science.gov (United States)

    Bargar, J.R.; Fuller, C.C.; Marcus, M.A.; Brearley, A.J.; Perez De la Rosa, M.; Webb, S.M.; Caldwell, W.A.

    2009-01-01

    The microbial catalysis of Mn(II) oxidation is believed to be a dominant source of abundant sorption- and redox-active Mn oxides in marine, freshwater, and subsurface aquatic environments. In spite of their importance, environmental oxides of known biogenic origin have generally not been characterized in detail from a structural perspective. Hyporheic zone Mn oxide grain coatings at Pinal Creek, Arizona, a metals-contaminated stream, have been identified as being dominantly microbial in origin and are well studied from bulk chemistry and contaminant hydrology perspectives. This site thus presents an excellent opportunity to study the structures of terrestrial microbial Mn oxides in detail. XRD and EXAFS measurements performed in this study indicate that the hydrated Pinal Creek Mn oxide grain coatings are layer-type Mn oxides with dominantly hexagonal or pseudo-hexagonal layer symmetry. XRD and TEM measurements suggest the oxides to be nanoparticulate plates with average dimensions on the order of 11 nm thick ?? 35 nm diameter, but with individual particles exhibiting thickness as small as a single layer and sheets as wide as 500 nm. The hydrated oxides exhibit a 10-?? basal-plane spacing and turbostratic disorder. EXAFS analyses suggest the oxides contain layer Mn(IV) site vacancy defects, and layer Mn(III) is inferred to be present, as deduced from Jahn-Teller distortion of the local structure. The physical geometry and structural details of the coatings suggest formation within microbial biofilms. The biogenic Mn oxides are stable with respect to transformation into thermodynamically more stable phases over a time scale of at least 5 months. The nanoparticulate layered structural motif, also observed in pure culture laboratory studies, appears to be characteristic of biogenic Mn oxides and may explain the common occurrence of this mineral habit in soils and sediments. ?? 2008 Elsevier Ltd.

  8. Mitigation of greenhouse gases emissions impact and their influence on terrestrial ecosystem.

    Science.gov (United States)

    Wójcik Oliveira, K.; Niedbała, G.

    2018-05-01

    Nowadays, one of the most important challenges faced by the humanity in the current century is the increasing temperature on Earth, caused by a growing emission of greenhouse gases into the atmosphere. Terrestrial ecosystems, as an important component of the carbon cycle, play an important role in the sequestration of carbon, which is a chance to improve the balance of greenhouse gases. Increasing CO2 absorption by terrestrial ecosystems is one way to reduce the atmospheric CO2 emissions. Sequestration of CO2 by terrestrial ecosystems is not yet fully utilized method of mitigating CO2 emission to the atmosphere. Terrestrial ecosystems, especially forests, are essential for the regulation of CO2 content in the atmosphere and more attention should be paid to seeking the natural processes of CO2 sequestration.

  9. Detecting Changes in Forest Structure over Time with Bi-Temporal Terrestrial Laser Scanning Data

    Directory of Open Access Journals (Sweden)

    Timo Melkas

    2012-10-01

    Full Text Available Changes to stems caused by natural forces and timber harvesting constitute an essential input for many forestry-related applications and ecological studies, especially forestry inventories based on the use of permanent sample plots. Conventional field measurement is widely acknowledged as being time-consuming and labor-intensive. More automated and efficient alternatives or supportive methods are needed. Terrestrial laser scanning (TLS has been demonstrated to be a promising method in forestry field inventories. Nevertheless, the applicability of TLS in recording changes in the structure of forest plots has not been studied in detail. This paper presents a fully automated method for detecting changes in forest structure over time using bi-temporal TLS data. The developed method was tested on five densely populated forest plots including 137 trees and 50 harvested trees in point clouds. The present study demonstrated that 90 percent of tree stem changes could be automatically located from single-scan TLS data. These changes accounted for 92 percent of the changed basal area. The results indicate that the processing of TLS data collected at different times to detect tree stem changes can be fully automated.

  10. Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact approximate to 12,800 Years Ago. 2. Lake, Marine, and Terrestrial Sediments

    Czech Academy of Sciences Publication Activity Database

    Wolbach, W. S.; Ballard, J. P.; Mayewski, P. A.; Parnell, A. C.; Cahill, N.; Adedeji, V.; Bunch, T. E.; Dominguez-Vazquez, G.; Erlandson, J. M.; Firestone, R. B.; French, T. A.; Howard, G.; Israde-Alcántara, I.; Johnson, J. R.; Kimbel, D.; Kinzie, Ch. R.; Kurbatov, A.; Kletetschka, Günther; LeCompte, M. A.; Mahaney, W. C.; Mellot, A. L.; Mitra, S.; Maiorana-Boutilier, A.; Moore, Ch. R.; Napier, W. M.; Parlier, J.; Tankersley, K. B.; Thomas, B. C.; Wittke, J. H.; West, A.; Kennett, J. P.

    2018-01-01

    Roč. 126, č. 2 (2018), s. 185-205 ISSN 0022-1376 Institutional support: RVO:67985831 Keywords : biomass burning * climate feedback * climate variation * ice core * lacustrine deposit * marine sediment * paleoclimate * quantitative analysis * terrestrial deposit * winter * Younger Dryas Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.952, year: 2016

  11. Water and the Interior Structure of Terrestrial Planets and Icy Bodies

    Science.gov (United States)

    Monteux, J.; Golabek, G. J.; Rubie, D. C.; Tobie, G.; Young, E. D.

    2018-02-01

    Water content and the internal evolution of terrestrial planets and icy bodies are closely linked. The distribution of water in planetary systems is controlled by the temperature structure in the protoplanetary disk and dynamics and migration of planetesimals and planetary embryos. This results in the formation of planetesimals and planetary embryos with a great variety of compositions, water contents and degrees of oxidation. The internal evolution and especially the formation time of planetesimals relative to the timescale of radiogenic heating by short-lived 26Al decay may govern the amount of hydrous silicates and leftover rock-ice mixtures available in the late stages of their evolution. In turn, water content may affect the early internal evolution of the planetesimals and in particular metal-silicate separation processes. Moreover, water content may contribute to an increase of oxygen fugacity and thus affect the concentrations of siderophile elements within the silicate reservoirs of Solar System objects. Finally, the water content strongly influences the differentiation rate of the icy moons, controls their internal evolution and governs the alteration processes occurring in their deep interiors.

  12. Terrestrial Laser Scanning-Based Bridge Structural Condition Assessment : Tech Transfer Summaries

    Science.gov (United States)

    2016-05-01

    Problem Statement : While several state departments of transportation (DOTs) have used : terrestrial laser scanning (TLS) in the project planning phase, limited : research has been conducted on employing laser scanners to detect : cracks for bridge c...

  13. Terrestrial exposure of oilfield flowline additives diminish soil structural stability and remediative microbial function

    International Nuclear Information System (INIS)

    George, S.J.; Sherbone, J.; Hinz, C.; Tibbett, M.

    2011-01-01

    Onshore oil production pipelines are major installations in the petroleum industry, stretching many thousands of kilometres worldwide which also contain flowline additives. The current study focuses on the effect of the flowline additives on soil physico-chemical and biological properties and quantified the impact using resilience and resistance indices. Our findings are the first to highlight deleterious effect of flowline additives by altering some fundamental soil properties, including a complete loss of structural integrity of the impacted soil and a reduced capacity to degrade hydrocarbons mainly due to: (i) phosphonate salts (in scale inhibitor) prevented accumulation of scale in pipelines but also disrupted soil physical structure; (ii) glutaraldehyde (in biocides) which repressed microbial activity in the pipeline and reduced hydrocarbon degradation in soil upon environmental exposure; (iii) the combinatory effects of these two chemicals synergistically caused severe soil structural collapse and disruption of microbial degradation of petroleum hydrocarbons. - Highlights: → Effects of flowline additives on soil structure and microbial function highlighted. → Phosphonate salts (in scale inhibitor) were found to disrupt soil physical structure. → Glutaraldehyde (in biocides) caused significant reduction of hydrocarbon degradation in soil. → Flowline additive chemicals synergistically affects soil structure and remediative microbial function. - Scale inhibitor and biocide oilfield flowline additives interactively affect soil physical and microbial properties

  14. Impacts of Environmental Nanoparticles on Chemical, Biological and Hydrological Processes in Terrestrial Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla

    2012-01-01

    This chapter provides insights on nanoparticle (NP) influence or control on the extent and timescales of single or coupled physical, chemical, biological and hydrological reactions and processes that occur in terrestrial ecosystems. Examples taken from the literature that show how terrestrial NPs may determine the fate of the aqueous and sorbed (adsorbed or precipitated) chemical species of nutrients and contaminants, are also included in this chapter. Specifically, in the first section, chapter objectives, term definitions and discussions on size-dependent properties, the origin and occurrence of NP in terrestrial ecosystems and NP toxicity, are included. In the second section, the topic of the binary interactions of NPs of different sizes, shapes, concentrations and ages with the soil solution chemical species is covered, focusing on NP formation, stability, aggregation, ability to serve as sorbents, or surface-mediated precipitation catalysts, or electron donors and acceptors. In the third section, aspects of the interactions in the ternary systems composed of environmental NP, nutrient/contaminant chemical species, and the soil/sediment matrix are discussed, focusing on the inhibitory and catalytic effects of environmental NP on nutrient/contaminant advective mobility and mass transfer, adsorption and desorption, dissolution and precipitation and redox reactions that occur in terrestrial ecosystems. These three review sections are followed by a short summary of future research needs and directions, the acknowledgements, the list of the references, and the figures.

  15. SIMULATING VARIOUS TERRESTRIAL AND UAV LIDAR SCANNING CONFIGURATIONS FOR UNDERSTORY FOREST STRUCTURE MODELLING

    Directory of Open Access Journals (Sweden)

    M. Hämmerle

    2017-09-01

    Full Text Available Information about the 3D structure of understory vegetation is of high relevance in forestry research and management (e.g., for complete biomass estimations. However, it has been hardly investigated systematically with state-of-the-art methods such as static terrestrial laser scanning (TLS or laser scanning from unmanned aerial vehicle platforms (ULS. A prominent challenge for scanning forests is posed by occlusion, calling for proper TLS scan position or ULS flight line configurations in order to achieve an accurate representation of understory vegetation. The aim of our study is to examine the effect of TLS or ULS scanning strategies on (1 the height of individual understory trees and (2 understory canopy height raster models. We simulate full-waveform TLS and ULS point clouds of a virtual forest plot captured from various combinations of max. 12 TLS scan positions or 3 ULS flight lines. The accuracy of the respective datasets is evaluated with reference values given by the virtually scanned 3D triangle mesh tree models. TLS tree height underestimations range up to 1.84 m (15.30 % of tree height for single TLS scan positions, but combining three scan positions reduces the underestimation to maximum 0.31 m (2.41 %. Combining ULS flight lines also results in improved tree height representation, with a maximum underestimation of 0.24 m (2.15 %. The presented simulation approach offers a complementary source of information for efficient planning of field campaigns aiming at understory vegetation modelling.

  16. Simulating Various Terrestrial and Uav LIDAR Scanning Configurations for Understory Forest Structure Modelling

    Science.gov (United States)

    Hämmerle, M.; Lukač, N.; Chen, K.-C.; Koma, Zs.; Wang, C.-K.; Anders, K.; Höfle, B.

    2017-09-01

    Information about the 3D structure of understory vegetation is of high relevance in forestry research and management (e.g., for complete biomass estimations). However, it has been hardly investigated systematically with state-of-the-art methods such as static terrestrial laser scanning (TLS) or laser scanning from unmanned aerial vehicle platforms (ULS). A prominent challenge for scanning forests is posed by occlusion, calling for proper TLS scan position or ULS flight line configurations in order to achieve an accurate representation of understory vegetation. The aim of our study is to examine the effect of TLS or ULS scanning strategies on (1) the height of individual understory trees and (2) understory canopy height raster models. We simulate full-waveform TLS and ULS point clouds of a virtual forest plot captured from various combinations of max. 12 TLS scan positions or 3 ULS flight lines. The accuracy of the respective datasets is evaluated with reference values given by the virtually scanned 3D triangle mesh tree models. TLS tree height underestimations range up to 1.84 m (15.30 % of tree height) for single TLS scan positions, but combining three scan positions reduces the underestimation to maximum 0.31 m (2.41 %). Combining ULS flight lines also results in improved tree height representation, with a maximum underestimation of 0.24 m (2.15 %). The presented simulation approach offers a complementary source of information for efficient planning of field campaigns aiming at understory vegetation modelling.

  17. Impact of the earthworm Lumbricus terrestris (L.) on As, Cu, Pb and Zn mobility and speciation in contaminated soils

    International Nuclear Information System (INIS)

    Sizmur, Tom; Palumbo-Roe, Barbara; Watts, Michael J.; Hodson, Mark E.

    2011-01-01

    To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota. - Research highlights: → Earthworms increase the mobility and availability of metals and metalloids in soils. → We incubated L. terrestris in three soils contaminated with As, Cu, Pb and Zn. → Earthworms increased the mobility of As, Cu, Pb and Zn in their casts. → The mechanisms for this could be explained by changes in pH or organic carbon. - Lumbricus terrestris change the partitioning of metal(loid)s between soil constituents and increase the mobility of metal(loid)s in casts and pore water.

  18. The Impact of Prior Biosphere Models in the Inversion of Global Terrestrial CO2 Fluxes by Assimilating OCO-2 Retrievals

    Science.gov (United States)

    Philip, Sajeev; Johnson, Matthew S.

    2018-01-01

    Atmospheric mixing ratios of carbon dioxide (CO2) are largely controlled by anthropogenic emissions and biospheric fluxes. The processes controlling terrestrial biosphere-atmosphere carbon exchange are currently not fully understood, resulting in terrestrial biospheric models having significant differences in the quantification of biospheric CO2 fluxes. Atmospheric transport models assimilating measured (in situ or space-borne) CO2 concentrations to estimate "top-down" fluxes, generally use these biospheric CO2 fluxes as a priori information. Most of the flux inversion estimates result in substantially different spatio-temporal posteriori estimates of regional and global biospheric CO2 fluxes. The Orbiting Carbon Observatory 2 (OCO-2) satellite mission dedicated to accurately measure column CO2 (XCO2) allows for an improved understanding of global biospheric CO2 fluxes. OCO-2 provides much-needed CO2 observations in data-limited regions facilitating better global and regional estimates of "top-down" CO2 fluxes through inversion model simulations. The specific objectives of our research are to: 1) conduct GEOS-Chem 4D-Var assimilation of OCO-2 observations, using several state-of-the-science biospheric CO2 flux models as a priori information, to better constrain terrestrial CO2 fluxes, and 2) quantify the impact of different biospheric model prior fluxes on OCO-2-assimilated a posteriori CO2 flux estimates. Here we present our assessment of the importance of these a priori fluxes by conducting Observing System Simulation Experiments (OSSE) using simulated OCO-2 observations with known "true" fluxes.

  19. Impact of the earthworm Lumbricus terrestris (L.) on As, Cu, Pb and Zn mobility and speciation in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Sizmur, Tom, E-mail: t.p.sizmur@reading.ac.uk [Soil Research Centre, Department of Geography and Environmental Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading RG6 6DW (United Kingdom); Palumbo-Roe, Barbara; Watts, Michael J. [British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Hodson, Mark E. [Soil Research Centre, Department of Geography and Environmental Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading RG6 6DW (United Kingdom)

    2011-03-15

    To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota. - Research highlights: > Earthworms increase the mobility and availability of metals and metalloids in soils. > We incubated L. terrestris in three soils contaminated with As, Cu, Pb and Zn. > Earthworms increased the mobility of As, Cu, Pb and Zn in their casts. > The mechanisms for this could be explained by changes in pH or organic carbon. - Lumbricus terrestris change the partitioning of metal(loid)s between soil constituents and increase the mobility of metal(loid)s in casts and pore water.

  20. Impacts of droughts on carbon sequestration by China's terrestrial ecosystems from 2000 to 2011

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Wang, S.; Wu, X.; He, M.; Zhu, G.

    2014-05-01

    In recent years, China's terrestrial ecosystems have experienced frequent droughts. How these droughts have affected carbon sequestration by the terrestrial ecosystems is still unclear. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model, driven by remotely sensed vegetation parameters, was employed to assess the effects of droughts on net ecosystem productivity (NEP) of terrestrial ecosystems in China from 2000 to 2011. Droughts of differing severity, as indicated by a standard precipitation index (SPI), hit terrestrial ecosystems in China extensively in 2001, 2006, 2009, and 2011. The national total annual NEP exhibited the slight decline of -11.3 Tg C yr-2 during the aforementioned years of extensive droughts. The NEP reduction ranged from 61.1 Tg C yr-1 to 168.8 Tg C yr-1. National and regional total NEP anomalies were correlated with the annual mean SPI, especially in Northwest China, North China, Central China, and Southwest China. The reductions in annual NEP in 2001 and 2011 might have been caused by a larger decrease in annual gross primary productivity (GPP) than in annual ecosystem respiration (ER). The reductions experienced in 2009 might be due to a decrease in annual GPP and an increase in annual ER, while reductions in 2006 could stem from a larger increase in ER than in GPP. The effects of droughts on NEP lagged up to 3-6 months, due to different responses of GPP and ER. In eastern China, where is humid and warm, droughts have predominant and short-term lagged influences on NEP. In western regions, cold and arid, the drought effects on NEP were relatively weaker but prone to lasting longer.

  1. Terrestrial mammal assemblages in protected and human impacted areas in Northern Brazilian Amazonia

    Directory of Open Access Journals (Sweden)

    Rodolfo Burgos de Luna

    2017-10-01

    Full Text Available Mammal communities in the vicinity of human settlements are often subject to subsistence hunting and retaliatory killings. We used fourteen digital camera traps equipped with infrared triggers to sample the medium-sized and large mammal communities for ca. 34 (±1.64 days per site. Diversity was measured as both Shannon entropy and Fager´s number of moves (NMS, and dominance was quantified using the Berger-Parker index. We used Kruskall-Wallis tests to investigate if there were statistically significant differences in richness, diversity and dominance among the sites. At an overall sampling effort of 1,946 trap days we recorded 216 independent observations of a total of 20 species belonging to 17 genera and 15 families. Richness and diversity appeared to be determined by forest structure, since, independent of the level of human impact, the richest areas were those closest to the ombrophilous forests of southern Guyana shield, closest to central Amazonia, whereas the poorest were at those sites closest to the vegetation mosaics of central Guyana shield. The disappearance of Tayassu pecari from the impacted areas as well as higher relative abundances in the protected areas, albeit not significant, foresees a possible bleak future for the mammalian assemblages in the near future.

  2. The Gardnos Impact Structure, Norway

    Science.gov (United States)

    Dons, J. A.; Naterstad, J.

    1992-07-01

    The Gardnos area is situated 9 km north of the village Nesbyen in the county of Buskerud, south-central Norway. The peculiar "Gardnos breccia" was first described in 1945 and ascribed to explosive volcanic activity in Permian time. This conclusion has lately been questioned, and preliminary field and microscopic investigations by the authors in 1990-91 substantiated a theory of impact origin for the breccia and the structure. The Gardnos Impact Structure is the first of its kind to be described from Norway. Its geographical position is lat. 60 degrees 39'N, long. 9 degrees 00'E. The topography surrounding the structure ranges from 200 m.a.s.l. in the main Hallingdalen valley to more than 1000 m.a.s.l. in the high mountains nearby. At heights of 900-1000 m erosion has cut through the important, more or less horizontal boundary between a complex Precambrian crystalline basement and a deformed Caledonian cover sequence of Cambro-Ordovician sediments and overthrust nappes. Rocks of the latter sequence are however, still preserved in outliers no more than 3 km from the Gardnos structure. Erosional remnants of the Gardnos structure rocks are found within a semicircular area of 4-5 km diameter. Topographically the eroded structure now appears as a bowl-shaped, hanging side valley to Hallingdal. Wooded, late-Quaternary moraines and fluvioglacial deposits cover to a great extent the solid rocks, but the beds of many branching creeks provide good exposures. Thus a great variety of rocks formed within the Gardnos structure can be studied from approximately 350 m.a.s.l. up to more than 800 m.a.s.l. A variety of rocks from the Precambrian basement complex have been affected by the impact. This gives a unique opportunity to study shock-metamorphic effects on varying lithologies. Among the impact-produced structures and rock types that can easily be identified is an outer zone of breccia veining in the varied Precambrian lithologies, a lowermost lens of autochthonous breccia, the

  3. Impacts of large-scale climatic disturbances on the terrestrial carbon cycle

    Directory of Open Access Journals (Sweden)

    Lucht Wolfgang

    2006-07-01

    Full Text Available Abstract Background The amount of carbon dioxide in the atmosphere steadily increases as a consequence of anthropogenic emissions but with large interannual variability caused by the terrestrial biosphere. These variations in the CO2 growth rate are caused by large-scale climate anomalies but the relative contributions of vegetation growth and soil decomposition is uncertain. We use a biogeochemical model of the terrestrial biosphere to differentiate the effects of temperature and precipitation on net primary production (NPP and heterotrophic respiration (Rh during the two largest anomalies in atmospheric CO2 increase during the last 25 years. One of these, the smallest atmospheric year-to-year increase (largest land carbon uptake in that period, was caused by global cooling in 1992/93 after the Pinatubo volcanic eruption. The other, the largest atmospheric increase on record (largest land carbon release, was caused by the strong El Niño event of 1997/98. Results We find that the LPJ model correctly simulates the magnitude of terrestrial modulation of atmospheric carbon anomalies for these two extreme disturbances. The response of soil respiration to changes in temperature and precipitation explains most of the modelled anomalous CO2 flux. Conclusion Observed and modelled NEE anomalies are in good agreement, therefore we suggest that the temporal variability of heterotrophic respiration produced by our model is reasonably realistic. We therefore conclude that during the last 25 years the two largest disturbances of the global carbon cycle were strongly controlled by soil processes rather then the response of vegetation to these large-scale climatic events.

  4. Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

    Institute of Scientific and Technical Information of China (English)

    W. Kolby SMITH; Wei GAO; Heidi STELTZER

    2009-01-01

    One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth's surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

  5. Impact of chronic, low-level ionising radiation exposure on terrestrial invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Hingston, J.; Wood, M.D.; Copplestone, D.; Zinger, I. [Liverpool Univ., School of Biological Sciences, Merseyside (United Kingdom)

    2004-07-01

    There is a need to confirm that the environment is being adequately protected from the mixture of contaminants released into it. In the field of environmental radioactivity, tools have been developed to assess the impacts of ionising radiation on wildlife. The scientific data upon which these assessments are based is, however, lacking. New documentation has been produced by the UK Environment Agency to provide guidelines on structuring experiments (using environmentally relevant doses) and select suitable non-human species and endpoints for study. It is anticipated that this documentation will be used to direct future experiments in this field. This paper presents the results of the first of these experiments. Numbers of the earthworm Eisenia fetida and the wood louse Porcellio scaber were segregated and constantly exposed to one of six radiation doses (background, 0.1, 0.4, 1.5, 4.0 and 8.0 mGyh{sup -1}) for a total of 16 and 14 weeks respectively. The endpoints of mortality, number of viable offspring and average weight of an individual were recorded and the results of this study will be discussed here. (author)

  6. Assessment of land use impact on water-related ecosystem services capturing the integrated terrestrial-aquatic system.

    Science.gov (United States)

    Maes, Wouter H; Heuvelmans, Griet; Muys, Bart

    2009-10-01

    Although the importance of green (evaporative) water flows in delivering ecosystem services has been recognized, most operational impact assessment methods still focus only on blue water flows. In this paper, we present a new model to evaluate the effect of land use occupation and transformation on water quantity. Conceptually based on the supply of ecosystem services by terrestrial and aquatic ecosystems, the model is developed for, but not limited to, land use impact assessment in life cycle assessment (LCA) and requires a minimum amount of input data. Impact is minimal when evapotranspiration is equal to that of the potential natural vegetation, and maximal when evapotranspiration is zero or when it exceeds a threshold value derived from the concept of environmental water requirement. Three refinements to the model, requiring more input data, are proposed. The first refinement considers a minimal impact over a certain range based on the boundary evapotranspiration of the potential natural vegetation. In the second refinement the effects of evaporation and transpiration are accounted for separately, and in the third refinement a more correct estimate of evaporation from a fully sealed surface is incorporated. The simplicity and user friendliness of the proposed impact assessment method are illustrated with two examples.

  7. Assessing hydrometeorological impacts with terrestrial and aerial Lidar data in Monterrey, México

    Science.gov (United States)

    Yepez Rincon, F.; Lozano Garcia, D.; Vela Coiffier, P.; Rivera Rivera, L.

    2013-10-01

    Light Detection Ranging (Lidar) is an efficient tool to gather points reflected from a terrain and store them in a xyz coordinate system, allowing the generation of 3D data sets to manage geoinformation. Translation of these coordinates, from an arbitrary system into a geographical base, makes data feasible and useful to calculate volumes and define topographic characteristics at different scales. Lidar technological advancement in topographic mapping enables the generation of highly accurate and densely sampled elevation models, which are in high demand by many industries like construction, mining and forestry. This study merges terrestrial and aerial Lidar data to evaluate the effectiveness of these tools assessing volumetric changes after a hurricane event of riverbeds and scour bridges The resulted information could be an optimal approach to improve hydrological and hydraulic models, to aid authorities in proper to decision making in construction, urban planning, and homeland security.

  8. The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

    Science.gov (United States)

    Hudson, Lawrence N; Newbold, Tim; Contu, Sara; Hill, Samantha L L; Lysenko, Igor; De Palma, Adriana; Phillips, Helen R P; Senior, Rebecca A; Bennett, Dominic J; Booth, Hollie; Choimes, Argyrios; Correia, David L P; Day, Julie; Echeverría-Londoño, Susy; Garon, Morgan; Harrison, Michelle L K; Ingram, Daniel J; Jung, Martin; Kemp, Victoria; Kirkpatrick, Lucinda; Martin, Callum D; Pan, Yuan; White, Hannah J; Aben, Job; Abrahamczyk, Stefan; Adum, Gilbert B; Aguilar-Barquero, Virginia; Aizen, Marcelo A; Ancrenaz, Marc; Arbeláez-Cortés, Enrique; Armbrecht, Inge; Azhar, Badrul; Azpiroz, Adrián B; Baeten, Lander; Báldi, András; Banks, John E; Barlow, Jos; Batáry, Péter; Bates, Adam J; Bayne, Erin M; Beja, Pedro; Berg, Åke; Berry, Nicholas J; Bicknell, Jake E; Bihn, Jochen H; Böhning-Gaese, Katrin; Boekhout, Teun; Boutin, Céline; Bouyer, Jérémy; Brearley, Francis Q; Brito, Isabel; Brunet, Jörg; Buczkowski, Grzegorz; Buscardo, Erika; Cabra-García, Jimmy; Calviño-Cancela, María; Cameron, Sydney A; Cancello, Eliana M; Carrijo, Tiago F; Carvalho, Anelena L; Castro, Helena; Castro-Luna, Alejandro A; Cerda, Rolando; Cerezo, Alexis; Chauvat, Matthieu; Clarke, Frank M; Cleary, Daniel F R; Connop, Stuart P; D'Aniello, Biagio; da Silva, Pedro Giovâni; Darvill, Ben; Dauber, Jens; Dejean, Alain; Diekötter, Tim; Dominguez-Haydar, Yamileth; Dormann, Carsten F; Dumont, Bertrand; Dures, Simon G; Dynesius, Mats; Edenius, Lars; Elek, Zoltán; Entling, Martin H; Farwig, Nina; Fayle, Tom M; Felicioli, Antonio; Felton, Annika M; Ficetola, Gentile F; Filgueiras, Bruno K C; Fonte, Steven J; Fraser, Lauchlan H; Fukuda, Daisuke; Furlani, Dario; Ganzhorn, Jörg U; Garden, Jenni G; Gheler-Costa, Carla; Giordani, Paolo; Giordano, Simonetta; Gottschalk, Marco S; Goulson, Dave; Gove, Aaron D; Grogan, James; Hanley, Mick E; Hanson, Thor; Hashim, Nor R; Hawes, Joseph E; Hébert, Christian; Helden, Alvin J; Henden, John-André; Hernández, Lionel; Herzog, Felix; Higuera-Diaz, Diego; Hilje, Branko; Horgan, Finbarr G; Horváth, Roland; Hylander, Kristoffer; Isaacs-Cubides, Paola; Ishitani, Masahiro; Jacobs, Carmen T; Jaramillo, Víctor J; Jauker, Birgit; Jonsell, Mats; Jung, Thomas S; Kapoor, Vena; Kati, Vassiliki; Katovai, Eric; Kessler, Michael; Knop, Eva; Kolb, Annette; Kőrösi, Ádám; Lachat, Thibault; Lantschner, Victoria; Le Féon, Violette; LeBuhn, Gretchen; Légaré, Jean-Philippe; Letcher, Susan G; Littlewood, Nick A; López-Quintero, Carlos A; Louhaichi, Mounir; Lövei, Gabor L; Lucas-Borja, Manuel Esteban; Luja, Victor H; Maeto, Kaoru; Magura, Tibor; Mallari, Neil Aldrin; Marin-Spiotta, Erika; Marshall, E J P; Martínez, Eliana; Mayfield, Margaret M; Mikusinski, Grzegorz; Milder, Jeffrey C; Miller, James R; Morales, Carolina L; Muchane, Mary N; Muchane, Muchai; Naidoo, Robin; Nakamura, Akihiro; Naoe, Shoji; Nates-Parra, Guiomar; Navarrete Gutierrez, Dario A; Neuschulz, Eike L; Noreika, Norbertas; Norfolk, Olivia; Noriega, Jorge Ari; Nöske, Nicole M; O'Dea, Niall; Oduro, William; Ofori-Boateng, Caleb; Oke, Chris O; Osgathorpe, Lynne M; Paritsis, Juan; Parra-H, Alejandro; Pelegrin, Nicolás; Peres, Carlos A; Persson, Anna S; Petanidou, Theodora; Phalan, Ben; Philips, T Keith; Poveda, Katja; Power, Eileen F; Presley, Steven J; Proença, Vânia; Quaranta, Marino; Quintero, Carolina; Redpath-Downing, Nicola A; Reid, J Leighton; Reis, Yana T; Ribeiro, Danilo B; Richardson, Barbara A; Richardson, Michael J; Robles, Carolina A; Römbke, Jörg; Romero-Duque, Luz Piedad; Rosselli, Loreta; Rossiter, Stephen J; Roulston, T'ai H; Rousseau, Laurent; Sadler, Jonathan P; Sáfián, Szabolcs; Saldaña-Vázquez, Romeo A; Samnegård, Ulrika; Schüepp, Christof; Schweiger, Oliver; Sedlock, Jodi L; Shahabuddin, Ghazala; Sheil, Douglas; Silva, Fernando A B; Slade, Eleanor M; Smith-Pardo, Allan H; Sodhi, Navjot S; Somarriba, Eduardo J; Sosa, Ramón A; Stout, Jane C; Struebig, Matthew J; Sung, Yik-Hei; Threlfall, Caragh G; Tonietto, Rebecca; Tóthmérész, Béla; Tscharntke, Teja; Turner, Edgar C; Tylianakis, Jason M; Vanbergen, Adam J; Vassilev, Kiril; Verboven, Hans A F; Vergara, Carlos H; Vergara, Pablo M; Verhulst, Jort; Walker, Tony R; Wang, Yanping; Watling, James I; Wells, Konstans; Williams, Christopher D; Willig, Michael R; Woinarski, John C Z; Wolf, Jan H D; Woodcock, Ben A; Yu, Douglas W; Zaitsev, Andrey S; Collen, Ben; Ewers, Rob M; Mace, Georgina M; Purves, Drew W; Scharlemann, Jörn P W; Purvis, Andy

    2014-01-01

    Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015. PMID:25558364

  9. Three-Dimensional Reconstruction of the Virtual Plant Branching Structure Based on Terrestrial LIDAR Technologies and L-System

    Science.gov (United States)

    Gong, Y.; Yang, Y.; Yang, X.

    2018-04-01

    For the purpose of extracting productions of some specific branching plants effectively and realizing its 3D reconstruction, Terrestrial LiDAR data was used as extraction source of production, and a 3D reconstruction method based on Terrestrial LiDAR technologies combined with the L-system was proposed in this article. The topology structure of the plant architectures was extracted using the point cloud data of the target plant with space level segmentation mechanism. Subsequently, L-system productions were obtained and the structural parameters and production rules of branches, which fit the given plant, was generated. A three-dimensional simulation model of target plant was established combined with computer visualization algorithm finally. The results suggest that the method can effectively extract a given branching plant topology and describes its production, realizing the extraction of topology structure by the computer algorithm for given branching plant and also simplifying the extraction of branching plant productions which would be complex and time-consuming by L-system. It improves the degree of automation in the L-system extraction of productions of specific branching plants, providing a new way for the extraction of branching plant production rules.

  10. THREE-DIMENSIONAL RECONSTRUCTION OF THE VIRTUAL PLANT BRANCHING STRUCTURE BASED ON TERRESTRIAL LIDAR TECHNOLOGIES AND L-SYSTEM

    Directory of Open Access Journals (Sweden)

    Y. Gong

    2018-04-01

    Full Text Available For the purpose of extracting productions of some specific branching plants effectively and realizing its 3D reconstruction, Terrestrial LiDAR data was used as extraction source of production, and a 3D reconstruction method based on Terrestrial LiDAR technologies combined with the L-system was proposed in this article. The topology structure of the plant architectures was extracted using the point cloud data of the target plant with space level segmentation mechanism. Subsequently, L-system productions were obtained and the structural parameters and production rules of branches, which fit the given plant, was generated. A three-dimensional simulation model of target plant was established combined with computer visualization algorithm finally. The results suggest that the method can effectively extract a given branching plant topology and describes its production, realizing the extraction of topology structure by the computer algorithm for given branching plant and also simplifying the extraction of branching plant productions which would be complex and time-consuming by L-system. It improves the degree of automation in the L-system extraction of productions of specific branching plants, providing a new way for the extraction of branching plant production rules.

  11. Monitoring of recreational trail erosion using terrestrial structure-from-motion approach

    Science.gov (United States)

    Ewertowski, Marek; Tomczyk, Aleksandra

    2017-04-01

    Protected natural areas (PNAs) such as national and landscape parks as well as suburban green areas often constitute areas very popular among the visitors. Visitor pressure in PNAs is focused mainly on recreational trails, which facilitate activities such as hiking, cycling, horse riding. Trails prepared for different groups of users are among the most common types of infrastructure in PNAs, facilitating access to these areas. However, high visitor pressure can lead to increases in trail width and an associated increase in soil erosion. In case of extensive protected areas, the performing of regular geodetic monitoring using dGPS or laser scanning is expensive and therefore park managers often face a problem in selecting sites for impact monitoring. However, recent advances in technology enables the development of low-cost alternatives for traditional surveys. Consumer-grade cameras can be used to rapid acquire of photographs. The ground-based photographs can be subsequently processed through the structure-from-motion approach to generate detailed mosaics and digital elevation models of trail surfaces. It is possible to apply such models to study, monitor and quantify processes like soil erosion and vegetation trampling. In this study, we present methodological framework for monitoring of trail impact with the use of structure-from-motion approach and demonstrate its application based on examples from recreational trail located in suburban settings of Poznań. The data were collected on 10-meter long trail segment in June, July and October 2016 capturing the initial condition at the beginning of the months, and then two session pre-, and immediately after intense rainfall event, and the last session after termination of summer season. The total number of images was between 150 and 300 for each of the survey session. Dens point clouds were from 18 to 29 million points and were downsampled to DEM with 1 mm resolution. To detect surface changes, Digital elevation

  12. Responses of Aquatic Bacteria to Terrestrial Runoff: Effects on Community Structure and Key Taxonomic Groups

    Science.gov (United States)

    Le, Huong T.; Ho, Cuong T.; Trinh, Quan H.; Trinh, Duc A.; Luu, Minh T. N.; Tran, Hai S.; Orange, Didier; Janeau, Jean L.; Merroune, Asmaa; Rochelle-Newall, Emma; Pommier, Thomas

    2016-01-01

    Organic fertilizer application is often touted as an economical and effective method to increase soil fertility. However, this amendment may increase dissolved organic carbon (DOC) runoff into downstream aquatic ecosystems and may consequently alter aquatic microbial community. We focused on understanding the effects of DOC runoff from soils amended with compost, vermicompost, or biochar on the aquatic microbial community of a tropical reservoir. Runoff collected from a series of rainfall simulations on soils amended with different organic fertilizers was incubated for 16 days in a series of 200 L mesocosms filled with water from a downstream reservoir. We applied 454 high throughput pyrosequencing for bacterial 16S rRNA genes to analyze microbial communities. After 16 days of incubation, the richness and evenness of the microbial communities present decreased in the mesocosms amended with any organic fertilizers, except for the evenness in the mesocosms amended with compost runoff. In contrast, they increased in the reservoir water control and soil-only amended mesocosms. Community structure was mainly affected by pH and DOC concentration. Compared to the autochthonous organic carbon produced during primary production, the addition of allochthonous DOC from these organic amendments seemed to exert a stronger effect on the communities over the period of incubation. While the Proteobacteria and Actinobacteria classes were positively associated with higher DOC concentration, the number of sequences representing key bacterial groups differed between mesocosms particularly between the biochar runoff addition and the compost or vermi-compost runoff additions. The genera of Propionibacterium spp. and Methylobacterium spp. were highly abundant in the compost runoff additions suggesting that they may represent sentinel species of complex organic carbon inputs. Overall, this work further underlines the importance of studying the off-site impacts of organic fertilizers as

  13. How does soil erosion influence the terrestrial carbon cycle and the impacts of land use and land cover change?

    Science.gov (United States)

    Naipal, V.; Wang, Y.; Ciais, P.; Guenet, B.; Lauerwald, R.

    2017-12-01

    The onset of agriculture has accelerated soil erosion rates significantly, mobilizing vast quantities of soil organic carbon (SOC) globally. Studies show that at timescales of decennia to millennia this mobilized SOC can significantly alter previously estimated carbon emissions from land use and land cover change (LULCC). However, a full understanding of the impact of soil erosion on land-atmosphere carbon exchange is still missing. The aim of our study is to better constrain the terrestrial carbon fluxes by developing methods, which are compatible with earth system models (ESMs), and explicitly represent the links between soil erosion and carbon dynamics. For this we use an emulator that represents the carbon cycle of ORCHIDEE, which is the land component of the IPSL ESM, in combination with an adjusted version of the Revised Universal Soil Loss Equation (RUSLE) model. We applied this modeling framework at the global scale to evaluate how soil erosion influenced the terrestrial carbon cycle in the presence of elevated CO2, regional climate change and land use change. Here, we focus on the effects of soil detachment by erosion only and do not consider sediment transport and deposition. We found that including soil erosion in the SOC dynamics-scheme resulted in two times more SOC being lost during the historical period (1850-2005 AD). LULCC is the main contributor to this SOC loss, whose impact on the SOC stocks is significantly amplified by erosion. Regionally, the influence of soil erosion varies significantly, depending on the magnitude of the perturbations to the carbon cycle and the effects of LULCC and climate change on soil erosion rates. We conclude that it is necessary to include soil erosion in assessments of LULCC, and to explicitly consider the effects of elevated CO2 and climate change on the carbon cycle and on soil erosion, for better quantification of past, present, and future LULCC carbon emissions.

  14. Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

    International Nuclear Information System (INIS)

    Rozema, Jelte; Notten, Martje J.M.; Aerts, Rien; Gestel, Cornelis A.M. van; Hobbelen, Peter H.F.; Hamers, Timo H.M.

    2008-01-01

    This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded

  15. Ancient sedimentary structures in the Mars, that resemble macroscopic morphology, spatial associations, and temporal succession in terrestrial microbialites.

    Science.gov (United States)

    Noffke, Nora

    2015-02-01

    Sandstone beds of the Mars have been interpreted as evidence of an ancient playa lake environment. On Earth, such environments have been sites of colonization by microbial mats from the early Archean to the present time. Terrestrial microbial mats in playa lake environments form microbialites known as microbially induced sedimentary structures (MISS). On Mars, three lithofacies of the Gillespie Lake Member sandstone display centimeter- to meter-scale structures similar in macroscopic morphology to terrestrial MISS that include "erosional remnants and pockets," "mat chips," "roll-ups," "desiccation cracks," and "gas domes." The microbially induced sedimentary-like structures identified in Curiosity rover mission images do not have a random distribution. Rather, they were found to be arranged in spatial associations and temporal successions that indicate they changed over time. On Earth, if such MISS occurred with this type of spatial association and temporal succession, they would be interpreted as having recorded the growth of a microbially dominated ecosystem that thrived in pools that later dried completely: erosional pockets, mat chips, and roll-ups resulted from water eroding an ancient microbial mat-covered sedimentary surface; during the course of subsequent water recess, channels would have cut deep into the microbial mats, leaving erosional remnants behind; desiccation cracks and gas domes would have occurred during a final period of subaerial exposure of the microbial mats. In this paper, the similarities of the macroscopic morphologies, spatial associations, and temporal succession of sedimentary structures on Mars to MISS preserved on Earth has led to the following hypothesis: The sedimentary structures in the Mars are ancient MISS produced by interactions between microbial mats and their environment. Proposed here is a strategy for detecting, identifying, confirming, and differentiating possible MISS during current and future Mars missions.

  16. Gene expression in chicken reveals correlation with structural genomic features and conserved patterns of transcription in the terrestrial vertebrates.

    Directory of Open Access Journals (Sweden)

    Haisheng Nie

    Full Text Available BACKGROUND: The chicken is an important agricultural and avian-model species. A survey of gene expression in a range of different tissues will provide a benchmark for understanding expression levels under normal physiological conditions in birds. With expression data for birds being very scant, this benchmark is of particular interest for comparative expression analysis among various terrestrial vertebrates. METHODOLOGY/PRINCIPAL FINDINGS: We carried out a gene expression survey in eight major chicken tissues using whole genome microarrays. A global picture of gene expression is presented for the eight tissues, and tissue specific as well as common gene expression were identified. A Gene Ontology (GO term enrichment analysis showed that tissue-specific genes are enriched with GO terms reflecting the physiological functions of the specific tissue, and housekeeping genes are enriched with GO terms related to essential biological functions. Comparisons of structural genomic features between tissue-specific genes and housekeeping genes show that housekeeping genes are more compact. Specifically, coding sequence and particularly introns are shorter than genes that display more variation in expression between tissues, and in addition intergenic space was also shorter. Meanwhile, housekeeping genes are more likely to co-localize with other abundantly or highly expressed genes on the same chromosomal regions. Furthermore, comparisons of gene expression in a panel of five common tissues between birds, mammals and amphibians showed that the expression patterns across tissues are highly similar for orthologous genes compared to random gene pairs within each pair-wise comparison, indicating a high degree of functional conservation in gene expression among terrestrial vertebrates. CONCLUSIONS: The housekeeping genes identified in this study have shorter gene length, shorter coding sequence length, shorter introns, and shorter intergenic regions, there seems

  17. Canopy rainfall partitioning across an urbanization gradient in forest structure as characterized by terrestrial LiDAR

    Science.gov (United States)

    Mesta, D. C.; Van Stan, J. T., II; Yankine, S. A.; Cote, J. F.; Jarvis, M. T.; Hildebrandt, A.; Friesen, J.; Maldonado, G.

    2017-12-01

    As urbanization expands, greater forest area is shifting from natural stand structures to urban stand structures, like forest fragments and landscaped tree rows. Changes in forest canopy structure have been found to drastically alter the amount of rainwater reaching the surface. However, stormwater management models generally treat all forest structures (beyond needle versus broadleaved) similarly. This study examines the rainfall partitioning of Pinus spp. canopies along a natural-to-urban forest gradient and compares these to canopy structural measurements using terrestrial LiDAR. Throughfall and meteorological observations were also used to estimate parameters of the commonly-used Gash interception model. Preliminary findings indicate that as forest structure changed from natural, closed canopy conditions to semi-closed canopy fragments and, ultimately, to exposed urban landscaping tree rows, the interchange between throughfall and rainfall interception also changed. This shift in partitioning between throughfall and rainfall interception may be linked to intuitive parameters, like canopy closure and density, as well as more complex metrics, like the fine-scale patterning of gaps (ie, lacunarity). Thus, results indicate that not all forests of the same species should be treated the same by stormwater models. Rather, their canopy structural characteristics should be used to vary their hydrometeorological interactions.

  18. Impact of ecological doses of the most widespread phthalate on a terrestrial species, the ant Lasius niger.

    Science.gov (United States)

    Cuvillier-Hot, Virginie; Salin, Karine; Devers, Séverine; Tasiemski, Aurélie; Schaffner, Pauline; Boulay, Raphaël; Billiard, Sylvain; Lenoir, Alain

    2014-05-01

    Phthalates are synthetic contaminants released into the environment notably by plastic waste. Semi-volatile, they adsorb to atmospheric particles and get distributed in all ecosystems. Effects of this major anthropogenic pollution in economical species in aquatic habitats have attracted large interest. On the contrary, very few studies have focused on wild terrestrial species. Yet, these lipophilic molecules are easily trapped by insect cuticle; ants and other insects have been shown to permanently bear among their cuticular components a non-negligible proportion of phthalates, meaning that they suffer from chronic exposure to these pollutants. Oral route could also be an additional way of contamination, as phthalates tend to stick to any organic particle. We show here via a food choice experiment that Lasius niger workers can detect, and avoid feeding on, food contaminated with DEHP (DiEthyl Hexyl Phthalate), the most widespread phthalate found in nature. This suggests that the main source of contamination for ants is atmosphere and that doses measured on the cuticle correspond to the chronic exposure levels for these animals. Such an ecologically relevant dose of DEHP was used to contaminate ants in lab and to investigate their physiological impact. Over a chronic exposure (1 dose per week for 5 weeks), the egg-laying rate of queens was significantly reduced lending credence to endocrine disruptive properties of such a pollutant, as also described for aquatic invertebrates. On the contrary, short term exposure (24h) to a single dose of DEHP does not induce oxidative stress in ant workers as expected, but leads to activation of the immune system. Because of their very large distribution, their presence in virtually all terrestrial ecosystems and their representation at all trophic levels, ants could be useful indicators of contamination by phthalates, especially via monitoring the level of activation of their immune state. Copyright © 2014 Elsevier Inc. All

  19. Cross infectivity of Nosema bombi, transmission and impact on bumble bee colonies (Bombus terrestris)

    NARCIS (Netherlands)

    Steen, van der J.J.M.

    2005-01-01

    The project "Biodiversity, impact and control of microsporidia in bumble bee (bombus spp.) pollinators" (acronim "Pollinator parasites") within Key Action 5 of the Fifth framework R&D Programme Quality of LIfe and Management of Living Resources was initiated January 1, 2003 and terminates

  20. Conservation on international boundaries: the impact of security barriers on selected terrestrial mammals in four protected areas in Arizona, USA.

    Directory of Open Access Journals (Sweden)

    Jamie W McCallum

    Full Text Available Several thousand terrestrial protected areas (PAs lie on international boundaries. Because international boundaries can be focal points for trade, illegal activity and development, such PAs can be vulnerable to a range of anthropogenic threats. There is an increasing trend towards the erection of international boundary infrastructure (including fences, barriers and ditches in many parts of the world, which may reduce the risk of these anthropogenic threats to some PAs. However this may restrict home range and access to resources for some native species. We sought to understand the impacts of these two different types of threat by using camera traps to measure the activity level of humans, native and invasive mammals in four US PAs on the Mexican international boundary. Comparisons were made between treatment areas with barriers and those without. Results showed that puma and coati were more likely to appear in treatment areas without barriers, whereas humans were not observed more frequently in one treatment area over another. The suggestion is that the intermittent fencing present in this part of the world does affect some native species, but does not necessarily restrict the movement of humans (including illegal migrants, who may negatively impact native species.

  1. Estimation of structural attributes of walnut trees based on terrestrial laser scanning

    Directory of Open Access Journals (Sweden)

    J. Estornell

    2017-06-01

    Full Text Available Juglans regia L. (walnut is a tree of significant economic importance, usually cultivated for its seed used in the food market, and for its wood used in the furniture industry. The aim of this work was to develop regression models to predict crown parameters for walnut trees using a terrestrial laser scanner. A set of 30 trees was selected and the total height, crown height and crown diameter were measured in the field. The trees were also measured by a laser scanner and algorithms were applied to compute the crown volume, crown diameter, total and crown height. Linear regression models were calculated to estimate walnut tree parameters from TLS data. Good results were obtained with values of R2 between 0.90 and 0.98. In addition, to analyze whether coarser point cloud densities might affect the results, the point clouds for all trees were subsampled using different point densities: points every 0.005 m, 0.01 m, 0.05 m, 0.1 m, 0.25 m, 0.5 m, 1 m, and 2 m. New regression models were calculated to estimate field parameters. For total height and crown volume good estimations were obtained from TLS parameters derived for all subsampled point cloud (0.005 m – 2 m.

  2. [Functional organization and structure of the serotonergic neuronal network of terrestrial snail].

    Science.gov (United States)

    Nikitin, E S; Balaban, P M

    2011-01-01

    The extension of knowledge how the brain works requires permanent improvement of methods of recording of neuronal activity and increase in the number of neurons recorded simultaneously to better understand the collective work of neuronal networks and assemblies. Conventional methods allow simultaneous intracellular recording up to 2-5 neurons and their membrane potentials, currents or monosynaptic connections or observation of spiking of neuronal groups with subsequent discrimination of individual spikes with loss of details of the dynamics of membrane potential. We recorded activity of a compact group of serotonergic neurons (up to 56 simultaneously) in the ganglion of a terrestrial mollusk using the method of optical recording of membrane potential that allowed to record individual action potentials in details with action potential parameters and to reveal morphology of the neurons rcorded. We demonstrated clear clustering in the group in relation with the dynamics of action potentials and phasic or tonic components in the neuronal responses to external electrophysiological and tactile stimuli. Also, we showed that identified neuron Pd2 could induce activation of a significant number of neurons in the group whereas neuron Pd4 did not induce any activation. However, its activation is delayed with regard to activation of the reacting group of neurons. Our data strongly support the concept of possible delegation of the integrative function by the network to a single neuron.

  3. Deep drilling in the Chesapeake Bay impact structure - An overview

    Science.gov (United States)

    Gohn, G.S.; Koeberl, C.; Miller, K.G.; Reimold, W.U.

    2009-01-01

    The late Eocene Chesapeake Bay impact structure lies buried at moderate depths below Chesapeake Bay and surrounding landmasses in southeastern Virginia, USA. Numerous characteristics made this impact structure an inviting target for scientific drilling, including the location of the impact on the Eocene continental shelf, its threelayer target structure, its large size (??85 km diameter), its status as the source of the North American tektite strewn field, its temporal association with other late Eocene terrestrial impacts, its documented effects on the regional groundwater system, and its previously unstudied effects on the deep microbial biosphere. The Chesapeake Bay Impact Structure Deep Drilling Project was designed to drill a deep, continuously cored test hole into the central part of the structure. A project workshop, funding proposals, and the acceptance of those proposals occurred during 2003-2005. Initial drilling funds were provided by the International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS). Supplementary funds were provided by the National Aeronautics and Space Administration (NASA) Science Mission Directorate, ICDP, and USGS. Field operations were conducted at Eyreville Farm, Northampton County, Virginia, by Drilling, Observation, and Sampling of the Earth's Continental Crust (DOSECC) and the project staff during September-December 2005, resulting in two continuously cored, deep holes. The USGS and Rutgers University cored a shallow hole to 140 m in April-May 2006 to complete the recovered section from land surface to 1766 m depth. The recovered section consists of 1322 m of crater materials and 444 m of overlying postimpact Eocene to Pleistocene sediments. The crater section consists of, from base to top: basement-derived blocks of crystalline rocks (215 m); a section of suevite, impact melt rock, lithic impact breccia, and cataclasites (154 m); a thin interval of quartz sand and lithic blocks (26 m); a

  4. Assessing Structure and Condition of Temperate And Tropical Forests: Fusion of Terrestrial Lidar and Airborne Multi-Angle and Lidar Remote Sensing

    Science.gov (United States)

    Saenz, Edward J.

    Forests provide vital ecosystem functions and services that maintain the integrity of our natural and human environment. Understanding the structural components of forests (extent, tree density, heights of multi-story canopies, biomass, etc.) provides necessary information to preserve ecosystem services. Increasingly, remote sensing resources have been used to map and monitor forests globally. However, traditional satellite and airborne multi-angle imagery only provide information about the top of the canopy and little about the forest structure and understory. In this research, we investigative the use of rapidly evolving lidar technology, and how the fusion of aerial and terrestrial lidar data can be utilized to better characterize forest stand information. We further apply a novel terrestrial lidar methodology to characterize a Hemlock Woolly Adelgid infestation in Harvard Forest, Massachusetts, and adapt a dynamic terrestrial lidar sampling scheme to identify key structural vegetation profiles of tropical rainforests in La Selva, Costa Rica.

  5. Impact damages modeling in laminated composite structures

    Directory of Open Access Journals (Sweden)

    Kreculj Dragan D.

    2014-01-01

    Full Text Available Laminated composites have an important application in modern engineering structures. They are characterized by extraordinary properties, such as: high strength and stiffness and lightweight. Nevertheless, a serious obstacle to more widespread use of those materials is their sensitivity to the impact loads. Impacts cause initiation and development of certain types of damages. Failures that occur in laminated composite structures can be intralaminar and interlaminar. To date it was developed a lot of simulation models for impact damages analysis in laminates. Those models can replace real and expensive testing in laminated structures with a certain accuracy. By using specialized software the damage parameters and distributions can be determined (at certain conditions on laminate structures. With performing numerical simulation of impact on composite laminates there are corresponding results valid for the analysis of these structures.

  6. Structural design for aircraft impact loading

    International Nuclear Information System (INIS)

    Schmidt, R.; Heckhausen, H.; Chen, C.; Rieck, P.J.; Lemons, G.W.

    1977-01-01

    The Soft Shell-Hardcore approach to nuclear power plant auxiliary structure design was developed to attenuate the crash effects of impacting aircraft. This report is an initial investigation into defining the important structural features involved that would allow the Soft Shell-Hardcore design to successfully sustain the postulated aircraft impact. Also specified for purposes of this study are aircraft impact locations and the type and velocity of impacting aircraft. The purpose of this initial investigation is to determine the feasibility of the two 0.5 m thick walls of the Soft Shell with the simplest possible mathematical model

  7. Development of novel SSR markers for evaluation of genetic diversity and population structure in Tribulus terrestris L. (Zygophyllaceae).

    Science.gov (United States)

    Kaur, Kuljit; Sharma, Vikas; Singh, Vijay; Wani, Mohammad Saleem; Gupta, Raghbir Chand

    2016-12-01

    Tribulus terrestris L., commonly called puncture vine and gokhru, is an important member of Zygophyllaceae. The species is highly important in context to therapeutic uses and provides important active principles responsible for treatment of various diseases and also used as tonic. It is widely distributed in tropical regions of India and the world. However, status of its genetic diversity remained concealed due to lack of research work in this species. In present study, genetic diversity and structure of different populations of T. terrestris from north India was examined at molecular level using newly developed Simple Sequence Repeat (SSR) markers. In total, 20 primers produced 48 alleles in a size range of 100-500 bp with maximum (4) fragments amplified by TTMS-1, TTMS-25 and TTMS-33. Mean Polymorphism Information Content (PIC) and Marker Index (MI) were 0.368 and 1.01, respectively. Dendrogram showed three groups, one of which was purely containing accessions from Rajasthan while other two groups corresponded to Punjab and Haryana regions with intermixing of few other accessions. Analysis of molecular variance partitioned 76 % genetic variance within populations and 24 % among populations. Bayesian model based STRUCTURE analysis detected two genetic stocks for analyzed germplasm and also detected some admixed individuals. Different geographical populations of this species showed high level of genetic diversity. Results of present study can be useful in identifying diverse accessions and management of this plant resource. Moreover, the novel SSR markers developed can be utilized for various genetic analyses in this species in future.

  8. Impacts of 1, 1.5, and 2 Degree Warming on Arctic Terrestrial Snow and Sea Ice

    Science.gov (United States)

    Derksen, C.; Mudryk, L.; Howell, S.; Flato, G. M.; Fyfe, J. C.; Gillett, N. P.; Sigmond, M.; Kushner, P. J.; Dawson, J.; Zwiers, F. W.; Lemmen, D.; Duguay, C. R.; Zhang, X.; Fletcher, C. G.; Dery, S. J.

    2017-12-01

    The 2015 Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC) established the global temperature goal of "holding the increase in the global average temperature to below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels." In this study, we utilize multiple gridded snow and sea ice products (satellite retrievals; assimilation systems; physical models driven by reanalyses) and ensembles of climate model simulations to determine the impacts of observed warming, and project the relative impacts of the UNFCC future warming targets on Arctic seasonal terrestrial snow and sea ice cover. Observed changes during the satellite era represent the response to approximately 1°C of global warming. Consistent with other studies, analysis of the observational record (1970's to present) identifies changes including a shorter snow cover duration (due to later snow onset and earlier snow melt), significant reductions in spring snow cover and summer sea ice extent, and the loss of a large proportion of multi-year sea ice. The spatial patterns of observed snow and sea ice loss are coherent across adjacent terrestrial/marine regions. There are strong pattern correlations between snow and temperature trends, with weaker association between sea ice and temperature due to the additional influence of dynamical effects such wind-driven redistribution of sea ice. Climate model simulations from the Coupled Model Inter-comparison Project Phase 5(CMIP-5) multi-model ensemble, large initial condition ensembles of the Community Earth System Model (CESM) and Canadian Earth System Model (CanESM2) , and warming stabilization simulations from CESM were used to identify changes in snow and ice under further increases to 1.5°C and 2°C warming. The model projections indicate these levels of warming will be reached over the coming 2-4 decades. Warming to 1.5°C results in an increase in the

  9. The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

    Czech Academy of Sciences Publication Activity Database

    Fayle, Tom Maurice

    2014-01-01

    Roč. 4, č. 24 (2014), s. 4701-4735 ISSN 2045-7758 Grant - others:U.K. Natural Environment Research Council(GB) NE/J011193/1; U.K. Biotechnology and Biological Sciences Research Council(GB) BB/F017324/1 Institutional support: RVO:60077344 Keywords : data sharing * global change * habitat destruction Subject RIV: EH - Ecology, Behaviour Impact factor: 2.320, year: 2014 http://onlinelibrary.wiley.com/doi/10.1002/ece3.1303/epdf

  10. Impact source localisation in aerospace composite structures

    Science.gov (United States)

    De Simone, Mario Emanuele; Ciampa, Francesco; Boccardi, Salvatore; Meo, Michele

    2017-12-01

    The most commonly encountered type of damage in aircraft composite structures is caused by low-velocity impacts due to foreign objects such as hail stones, tool drops and bird strikes. Often these events can cause severe internal material damage that is difficult to detect and may lead to a significant reduction of the structure’s strength and fatigue life. For this reason there is an urgent need to develop structural health monitoring systems able to localise low-velocity impacts in both metallic and composite components as they occur. This article proposes a novel monitoring system for impact localisation in aluminium and composite structures, which is able to determine the impact location in real-time without a-priori knowledge of the mechanical properties of the material. This method relies on an optimal configuration of receiving sensors, which allows linearization of well-known nonlinear systems of equations for the estimation of the impact location. The proposed algorithm is based on the time of arrival identification of the elastic waves generated by the impact source using the Akaike Information Criterion. The proposed approach was demonstrated successfully on both isotropic and orthotropic materials by using a network of closely spaced surface-bonded piezoelectric transducers. The results obtained show the validity of the proposed algorithm, since the impact sources were detected with a high level of accuracy. The proposed impact detection system overcomes current limitations of other methods and can be retrofitted easily on existing aerospace structures allowing timely detection of an impact event.

  11. Contribution to the knowledge of threatened terrestrial fauna of Brazil: data from PETROBRAS environmental impact assessments

    Energy Technology Data Exchange (ETDEWEB)

    Basbaum, Marcos A.; Fonseca, Renata A.A. [SEEBLA - Servicos de Engenharia Emilio Baumgart Ltda., Rio de Janeiro, RJ (Brazil)], e-mail: mbasbaum.seebla@petrobras.com.br, e-mail: renataamorim.seebla@petrobras.com.br; Torggler, Bianca F.; Fernandes, Renato; Guimaraes, Ricardo Z.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)], e-mail: torggler@petrobras.com.br, e-mail: renatofer@petrobras.com.br, e-mail: rzaluar@petrobras.com.br

    2009-12-19

    One of the major problems related to the protection of threatened species in Brazil is the current lack of primary data on their occurrence. PETROBRAS, due to the processes of environmental licensing of new pipelines, held numerous studies on the occurrence of several species. Most of these studies took place in Atlantic Forest remnants located in the states of Sao Paulo, Rio de Janeiro, Minas Gerais, Espirito Santo, Bahia, Sergipe, Alagoas and Pernambuco. This study compared primary data from these Environmental Impact Assessments with the Brazilian list of threatened species published by MMA (Brazilian Ministry of Environment). Many threatened species were recorded in areas where native forest fragments are reduced in number and size, such as those in the Northeastern region. (author)

  12. Response of masonry structure under impact load

    International Nuclear Information System (INIS)

    Makovicka, D.

    1993-01-01

    The paper deals with interaction of a short gaseous impact wave with a plate structure. Analyses of dynamic bending, depending on the parameters of the structure and the impact wave (i.e. the stress and displacement field produced by the resulting incident and reflected wave) have been made by FEM. The calculated data was based on the real material properties of this structure. Pressures greater than computed limit pressures result in the failure of the structure. The calculated and experimental data are compared. (author)

  13. Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States

    International Nuclear Information System (INIS)

    Zhang Chi; Tian Hanqin; Chen, Guangsheng; Chappelka, Arthur; Xu Xiaofeng; Ren Wei; Hui Dafeng; Liu Mingliang; Lu Chaoqun; Pan, Shufen; Lockaby, Graeme

    2012-01-01

    Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 10 15 ) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance. - Highlights: ► A series of spatial and temporal urban/developed land maps were generated. ► Urbanization effects on regional carbon dynamics were studied with a process-based Dynamic Land Ecosystem Model (DLEM). ► Carbon storage of urban/developed land was comparable to that stored in cropland and shrubland in the Southern United States. ► Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. ► Urbanization resulted in carbon emission, but established urban areas may gradually accumulate carbon over time. - Urbanization has resulted in carbon release to the atmosphere, but established urban areas may gradually accumulate carbon over time.

  14. Asteroid impacts on terrestrial planets: the effects of super-Earths and the role of the ν6 resonance

    Science.gov (United States)

    Smallwood, Jeremy L.; Martin, Rebecca G.; Lepp, Stephen; Livio, Mario

    2018-01-01

    With N-body simulations of a planetary system with an asteroid belt, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the ν6 secular resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the Solar system is somewhat special in its lack of a super-Earth mass planet in the inner Solar system. We therefore first consider the effects of the presence of a super-Earth in the terrestrial planet region. We find a significant effect for super-Earths with a mass of around 10 M⊕ and a separation greater than about 0.7 au. For a super-Earth which is interior to the Earth's orbit, the number of asteroids colliding with Earth increases the closer the super-Earth is to the Earth's orbit. This is the result of multiple secular resonance locations causing more asteroids to be perturbed on to Earth-crossing orbits. When the super-Earth is placed exterior to Earth's orbit, the collision rate decreases substantially because the ν6 resonance no longer exists in the asteroid belt region. We also find that changing the semimajor axis of Saturn leads to a significant decrease in the asteroid collision rate, though increasing its mass increases the collision rate. These results may have implications for the habitability of exoplanetary systems.

  15. Interval Optimization Model Considering Terrestrial Ecological Impacts for Water Rights Transfer from Agriculture to Industry in Ningxia, China.

    Science.gov (United States)

    Sun, Lian; Li, Chunhui; Cai, Yanpeng; Wang, Xuan

    2017-06-14

    In this study, an interval optimization model is developed to maximize the benefits of a water rights transfer system that comprises industry and agriculture sectors in the Ningxia Hui Autonomous Region in China. The model is subjected to a number of constraints including water saving potential from agriculture and ecological groundwater levels. Ecological groundwater levels serve as performance indicators of terrestrial ecology. The interval method is applied to present the uncertainty of parameters in the model. Two scenarios regarding dual industrial development targets (planned and unplanned ones) are used to investigate the difference in potential benefits of water rights transfer. Runoff of the Yellow River as the source of water rights fluctuates significantly in different years. Thus, compensation fees for agriculture are calculated to reflect the influence of differences in the runoff. Results show that there are more available water rights to transfer for industrial development. The benefits are considerable but unbalanced between buyers and sellers. The government should establish a water market that is freer and promote the interest of agriculture and farmers. Though there has been some success of water rights transfer, the ecological impacts and the relationship between sellers and buyers require additional studies.

  16. Impact loads on nuclear power plant structures

    International Nuclear Information System (INIS)

    Riera, J.D.

    1993-01-01

    The first step in evaluation of a NPP design for protection against impact loading, is to identify those events that may be credible for a particular site. In connection with external, man-made events IAEA Safety Series No.50-SG-S5 provides a methodology for selecting the events that need to be considered. This presentation deals with modelling of interface forces in projectile impact against unyielding structures, vibrations induced by impact, penetration, scabbing and perforation effects

  17. Leg tendon glands in male bumblebees (Bombus terrestris): structure, secretion chemistry, and possible functions

    Czech Academy of Sciences Publication Activity Database

    Jarau, S.; Žáček, Petr; Šobotník, Jan; Vrkoslav, Vladimír; Hadravová, Romana; Coppée, Audrey; Vašíčková, Soňa; Jiroš, Pavel; Valterová, Irena

    2012-01-01

    Roč. 99, č. 12 (2012), s. 1039-1049 ISSN 0028-1042 R&D Projects: GA TA ČR TA01020969 Institutional support: RVO:61388963 Keywords : bumblebee * hydrocarbons * leg tendon glands * sex specific secretion * wax esters Subject RIV: CC - Organic Chemistry Impact factor: 2.144, year: 2012

  18. Impact analysis of composite aircraft structures

    Science.gov (United States)

    Pifko, Allan B.; Kushner, Alan S.

    1993-01-01

    The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.

  19. Terrestrial laser scanning-based bridge structural condition assessment : InTrans project reports.

    Science.gov (United States)

    2016-05-01

    Objective, accurate, and fast assessment of a bridges structural condition is critical to the timely assessment of safety risks. : Current practices for bridge condition assessment rely on visual observations and manual interpretation of reports a...

  20. The impact of fire on terrestrial tardigrade biodiversity: a first case-study from Portugal

    Directory of Open Access Journals (Sweden)

    Filipe Vicente

    2013-05-01

    Full Text Available Currently, loss of habitat is the greatest threat to biodiversity, yet little is known about its effect on microscopic animal taxa, such as Tardigrada. One of the causes of habitat destruction is forest fire, both natural and anthropogenic. The latter is commonly used in agriculture to kill insect pests, as a soil preparation, or conservation to create habitat mosaics. In Portugal, 42% of fire frequency is anthropogenic. There is no consensus on the impact of fires on biodiversity, with studies pointing towards different conclusions. Different methods and target taxonomic study groups may partly explain this paradigm. This study is the first into possible effects of habitat destruction on tardigrade populations, in which we analysed the taxonomic and genetic variations of tardigrades from a fire affected location in a Portuguese natural park. Sampling was performed over a 10-year period, from 2000 to 2010. The location was affected by a small fire in 1998 and a big fire in 2003. A total of 11 species from nine separate genera was recorded, from which 19 cox1 haplotypes were identified. Our data suggest a negative effect of a forest fire on tardigrade populations. Taxonomic and genetic richness, as well as abundance show lower levels in the years after a fire, compared with the preceding years. Additionally, the population recovered visibly faster after the small fire than after the bigger one. This is consistent with larger fires destroying larger forest areas, leaving fewer animals at a farther distance available for re-colonisation. Most species found before the main fire are also found after it, indicating these tardigrades have a high recolonisation capability. However, only three of all recorded haplotypes were found both pre and post the main fire, which indicates genetic diversity loss as a direct consequence of fire. Therefore, we conclude that habitat destruction by means of forest fire has a detrimental effect on tardigrade

  1. Impact damage reduction by structured surface geometry

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Fedorov, Vladimir; McGugan, Malcolm

    2018-01-01

    performance was observed for polyurethane-coated fibre composites with structured geometries at the back surfaces. Repeated impacts by rubber balls on the coated side caused damage and delamination of the coating. The laminates with structured back surfaces showed longer durability than those with a flat back...

  2. The Impact of Sound Structure on Morphology

    DEFF Research Database (Denmark)

    Laaha, Sabine; Kjærbæk, Laila; Basbøll, Hans

    2011-01-01

    This study examines the impact of sound structure on children’s acquisition of noun plural morphology, focussing on stem change. For this purpose, a threelevel classification of stem change properties according to sound structure is presented, with increasing opacity of the plural stem: no change...

  3. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 1).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. The paper does not provide guidelines but rather...

  4. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 2).

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ralph G. Anderson

    1984-01-01

    The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described in a series of appendices. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. ...

  5. How Do Terrestrial Determinants Impact the Response of Water Quality to Climate Drivers?—An Elasticity Perspective on the Water–Land–Climate Nexus

    Directory of Open Access Journals (Sweden)

    Afed U. Khan

    2017-11-01

    Full Text Available Investigating water–land–climate interactions is critical for urban development and watershed management. This study examined this nexus by elasticity and statistical approaches through the lens of three watersheds: The Yukon, Mekong and Murray. Here, this study reports the fundamental characteristics, explanations and ecological and management implications of terrestrial determinant influence on the response of water quality to climate drivers. The stability of the response, measured by climate elasticity of water quality (CEWQ, is highly dependent on terrestrial determinants, with strong impacts from anthropogenic biomes and low impacts from surficial geology. Compared to temperature elasticity, precipitation elasticity of water quality is more unstable due to its possible linkages with many terrestrial determinants. Correlation and linear models were developed for the interaction system, which uncovered many interesting scenarios. The results implied that watersheds with a higher ratio of rangeland biomes have a lower risk of instability as compared to watersheds with a higher proportion of dense settlement, cropland and forested biomes. This study discusses some of the most essential pathways where instability might adversely affect CEWQ parameters and recommends suggestions for policy makers to alleviate the instability impacts to bring sustainability to the water environment.

  6. Structural Health Monitoring for Impact Damage in Composite Structures.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

    2014-08-01

    Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

  7. Historical Photogrammetry and Terrestrial Laser Scanning for the 3d Virtual Reconstruction of Destroyed Structures: a Case Study in Italy

    Science.gov (United States)

    Bitelli, G.; Dellapasqua, M.; Girelli, V. A.; Sbaraglia, S.; Tinia, M. A.

    2017-05-01

    The current dramatic episodes of destruction of archaeological sites have again highlighted the problem of the safeguarding the threatened heritage and, if possible, recovering those damaged by all the armed conflicts of the past. The historical photogrammetry offers the possibility to recover a posteriori the geometrical and material properties of destroyed structures, reconstructing their 3D model to document, study and maintain their memory, until to support their real anastylosis. The presented work is about the 3D reconstruction of the civic tower of the little town of Sant'Alberto, near the city of Ravenna, Italy. The tower, as a symbol of resistance and pride of the town's population, was destroyed in December 1944 by German troops in retaliation, when they were forced to leave the area. A city committee has subsequently collected all the historical evidence concerning the tower, including a series of photographic images that can be used for the photogrammetric reconstruction; the images calibration and orientation have been solved using the geometric information derived by a terrestrial laser scanner survey realized in the area where the tower was originally located. Despite the scarcity and very poor quality of the available images, the conducted photogrammetric procedure has allowed a complete and qualitatively satisfying object reconstruction, also thanks to the use of geometric constraint tools offered by the chosen software. The integration between the obtained model of the old tower and the 3D TLS survey of the square made it possible to reconstruct the ancient situation of the area.

  8. Quantitative analysis of the impacts of terrestrial environmental factors on precipitation variation over the Beibu Gulf Economic Zone in Coastal Southwest China

    Science.gov (United States)

    Zhao, Yinjun; Deng, Qiyu; Lin, Qing; Cai, Chunting

    2017-03-01

    Taking the Guangxi Beibu Gulf Economic Zone as the study area, this paper utilizes the geographical detector model to quantify the feedback effects from the terrestrial environment on precipitation variation from 1985 to 2010 with a comprehensive consideration of natural factors (forest coverage rate, vegetation type, terrain, terrestrial ecosystem types, land use and land cover change) and social factors (population density, farmland rate, GDP and urbanization rate). First, we found that the precipitation trend rate in the Beibu Gulf Economic Zone is between -47 and 96 mm/10a. Second, forest coverage rate change (FCRC), urbanization rate change (URC), GDP change (GDPC) and population density change (PDC) have a larger contribution to precipitation change through land-surface feedback, which makes them the leading factors. Third, the human element is found to primarily account for the precipitation changes in this region, as humans are the active media linking and enhancing these impact factors. Finally, it can be concluded that the interaction of impact factor pairs has a significant effect compared to the corresponding single factor on precipitation changes. The geographical detector model offers an analytical framework to reveal the terrestrial factors affecting the precipitation change, which gives direction for future work on regional climate modeling and analyses.

  9. Polyamorphic Transformations in Fe-Ni-C Liquids: Implications for Chemical Evolution of Terrestrial Planets: Fe-Ni-C liquid structural change

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Xiaojing [Department of Geology and Geophysics, University of Hawai‘i at Mānoa, Honolulu HI USA; Hawaii Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, Honolulu HI USA; Chen, Bin [Hawaii Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, Honolulu HI USA; Wang, Jianwei [Department of Geology and Geophysics, Center for Computation and Technology, Louisiana State University, Baton Rouge LA USA; Kono, Yoshio [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne IL USA; Zhu, Feng [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor MI USA

    2017-12-01

    During the formation of the Earth's core, the segregation of metallic liquids from silicate mantle should have left behind evident geochemical imprints on both the mantle and the core. Some distinctive geochemical signatures of the mantle-derived rocks likely own their origin to the metal-silicate differentiation of the primitive Earth, setting our planet apart from undifferentiated meteorites as well as terrestrial planets or moons isotopically and compositionally. Understanding the chemical evolution of terrestrial planetary bodies requires knowledge on properties of both liquid iron alloys and silicates equilibrating under physicochemical conditions pertinent to the deep magma ocean. Here we report experimental and computational results on the pressure-induced structural evolution of iron-nickel liquids alloyed with carbon. Our X-ray diffraction experiments up to 7.3 gigapascals (GPa) demonstrate that Fe-Ni (Fe90Ni10) liquids alloyed with 3 and 5 wt % carbon undergo a polyamorphic liquid structure transition at approximately 5 GPa. Corroborating the experimental observations, our first-principles molecular dynamic calculations reveal that the structural transitions result from the marked prevalence of three-atom face-sharing polyhedral connections in the liquids at >5 GPa. The structure and polyamorphic transitions of liquid iron-nickel-carbon alloys govern their physical and chemical properties and may thus cast fresh light on the chemical evolution of terrestrial planets and moons.

  10. Scenarios of giant planet formation and evolution and their impact on the formation of habitable terrestrial planets.

    Science.gov (United States)

    Morbidelli, Alessandro

    2014-04-28

    In our Solar System, there is a clear divide between the terrestrial and giant planets. These two categories of planets formed and evolved separately, almost in isolation from each other. This was possible because Jupiter avoided migrating into the inner Solar System, most probably due to the presence of Saturn, and never acquired a large-eccentricity orbit, even during the phase of orbital instability that the giant planets most likely experienced. Thus, the Earth formed on a time scale of several tens of millions of years, by collision of Moon- to Mars-mass planetary embryos, in a gas-free and volatile-depleted environment. We do not expect, however, that this clear cleavage between the giant and terrestrial planets is generic. In many extrasolar planetary systems discovered to date, the giant planets migrated into the vicinity of the parent star and/or acquired eccentric orbits. In this way, the evolution and destiny of the giant and terrestrial planets become intimately linked. This paper discusses several evolutionary patterns for the giant planets, with an emphasis on the consequences for the formation and survival of habitable terrestrial planets. The conclusion is that we should not expect Earth-like planets to be typical in terms of physical and orbital properties and accretion history. Most habitable worlds are probably different, exotic worlds.

  11. Working group 4: Terrestrial

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A working group at a Canada/USA symposium on climate change and the Arctic identified major concerns and issues related to terrestrial resources. The group examined the need for, and the means of, involving resource managers and users at local and territorial levels in the process of identifying and examining the impacts and consequences of climatic change. Climatic change will be important to the Arctic because of the magnitude of the change projected for northern latitudes; the apparent sensitivity of its terrestrial ecosystems, natural resources, and human support systems; and the dependence of the social, cultural, and economic welfare of Arctic communities, businesses, and industries on the health and quality of their environment. Impacts of climatic change on the physical, biological, and associated socio-economic environment are outlined. Gaps in knowledge needed to quantify these impacts are listed along with their relationships with resource management. Finally, potential actions for response and adaptation are presented

  12. Impact- and earthquake- proof roof structure

    International Nuclear Information System (INIS)

    Shohara, Ryoichi.

    1990-01-01

    Building roofs are constituted with roof slabs, an earthquake proof layer at the upper surface thereof and an impact proof layer made of iron-reinforced concrete disposed further thereover. Since the roofs constitute an earthquake proof structure loading building dampers on the upper surface of the slabs by the concrete layer, seismic inputs of earthquakes to the buildings can be moderated and the impact-proof layer is formed, to ensure the safety to external conditions such as earthquakes or falling accidents of airplane in important facilities such as reactor buildings. (T.M.)

  13. Materials and structures under shock and impact

    CERN Document Server

    Bailly, Patrice

    2013-01-01

    In risk studies, engineers often have to consider the consequences of an accident leading to a shock on a construction. This can concern the impact of a ground vehicle or aircraft, or the effects of an explosion on an industrial site.This book presents a didactic approach starting with the theoretical elements of the mechanics of materials and structures, in order to develop their applications in the cases of shocks and impacts. The latter are studied on a local scale at first. They lead to stresses and strains in the form of waves propagating through the material, this movement then extending

  14. Terrestrial magnetosphere

    International Nuclear Information System (INIS)

    Pande, D.C.; Agarwal, D.C.

    1982-01-01

    This paper presents a review about terrestrial magnetosphere. During the last few years considerable investigation have been carried out about the properties of Solar Wind and its interaction with planetary magnetic fields. It is therefore of high importance to accumulate all the investigations in a comprehensive form. The paper reviews the property of earth's magnetosphere, magnetosheath, magneto pause, polar cusps, bow shook and plasma sheath. (author)

  15. Analysis of flexible structures under lateral impact

    International Nuclear Information System (INIS)

    Ramirez, D. F.; Razavi, H.

    2012-01-01

    Three methods for analysis of flexible structures under lateral impact are presented. The first proposed method (Method A) consists of: (1) modifying an available deceleration on a rigid target with conservation principles to account for structural flexibility; and (2) transient nonlinear analysis of the structure with the corrected forcing function. The second proposed method (Method B) is similar to Method A in obtaining the forcing function but it solves the equations of motion of an idealized two-degree-of-freedom system instead of directly using conservation principles. The last method simply provides the maximum force in the structure using the conservation of energy and linear momentum. A coupled simulation is also performed in LS-DYNA and compared against the proposed methods. A case study is presented to illustrate the applicability of all three methods and the LS-DYNA simulation. (authors)

  16. Analysis of aircraft impact to concrete structures

    International Nuclear Information System (INIS)

    Arros, Jorma; Doumbalski, Nikolay

    2007-01-01

    Analysis of aircraft impact to nuclear power plant structures is discussed utilizing a simplified model of a 'fictitious nuclear building' to perform analyses using LS-DYNA software, representing the loading: (i) by the Riera force history method and (ii) by modeling the crash by impacting a model of a plane similar to Boeing 747-400 to the structure (i.e., 'missile-target interaction method'). Points discussed include: (1) comparison of shock loading within the building as obtained from the Riera force history analysis versus from the missile-target interaction analysis, (2) sensitivity of the results on the assumed Riera force loading area, (3) linear versus nonlinear modeling and (4) on failure criteria

  17. Tree crown structural characterization: A study using terrestrial laser scanning and three-dimensional radiative transfer modeling

    Science.gov (United States)

    Moorthy, Inian

    Spectroscopic observational data for vegetated environments, have been coupled with 3D physically-based radiative transfer models for retrievals of biochemical and biophysical indicators of vegetation health and condition. With the recent introduction of Terrestrial Laser Scanning (TLS) units, there now exists a means of rapidly measuring intricate structural details of vegetation canopies, which can also serve as input into 3D radiative transfer models. In this investigation, Intelligent Laser Ranging and Imaging System (ILRIS-3D) data was acquired of individual tree crowns in laboratory, and field-based experiments. The ILRIS-3D uses the Time-Of-Flight (TOF) principle to measure the distances of objects based on the time interval between laser pulse exitance and return, upon reflection from an object. At the laboratory-level, this exploratory study demonstrated and validated innovative approaches for retrieving crown-level estimates of Leaf Area Index (LAI) (r2 = 0.98, rmse = 0.26m2/m2), a critical biophysical parameter for vegetation monitoring and modeling. These methods were implemented and expanded in field experiments conducted in olive (Olea europaea L.) orchards in Cordoba, Spain, where ILRIS-3D observations for 24 structurally-variable trees were made. Robust methodologies were developed to characterize diagnostic architectural parameters, such as tree height (r2 = 0.97, rmse = 0.21m), crown width (r 2 = 0.98, rmse = 0.12m), crown height (r2 = 0.81, rmse = 0.11m), crown volume (r2 = 0.99, rmse = 2.6m3), and LAI (r2 = 0.76, rmse = 0.27m2/ m2). These parameters were subsequently used as direct inputs into the Forest LIGHT (FLIGHT) 3D ray tracing model for characterization of the spectral behavior of the olive crowns. Comparisons between FLIGHT-simulated spectra and measured data showed small differences in the visible (measurements were significantly correlated to TLS-derived tree crown complexity metrics. The specific implications of internal crown

  18. Remote sensing the vulnerability of vegetation in natural terrestrial ecosystems

    Science.gov (United States)

    Alistair M. S. Smith; Crystal A. Kolden; Wade T. Tinkham; Alan F. Talhelm; John D. Marshall; Andrew T. Hudak; Luigi Boschetti; Michael J. Falkowski; Jonathan A. Greenberg; John W. Anderson; Andrew Kliskey; Lilian Alessa; Robert F. Keefe; James R. Gosz

    2014-01-01

    Climate change is altering the species composition, structure, and function of vegetation in natural terrestrial ecosystems. These changes can also impact the essential ecosystem goods and services derived from these ecosystems. Following disturbances, remote-sensing datasets have been used to monitor the disturbance and describe antecedent conditions as a means of...

  19. A lost generation of impact structures: Imaging the Arctic and Antarctic in magnetics and gravity

    Science.gov (United States)

    Purucker, M. E.

    2017-12-01

    The process of convection that drives plate tectonics has fragmented the early record on the continents, and subducted it in the oceans. Erosion blurs the upper surfaces of impact structures exposed to the atmosphere beyond recognition after a few million years. The largest confirmed impact structures on the Earth are Vredefort, Chicxulub, and Sudbury, with crater diameters averaging 150 km, and maximum ages of about 2 Ga. Contrast this with the situation at Mars or the Moon, where the largest confirmed impact structures have diameters of 2000 km, and ages of 4 Ga. The giant impact basins that form the most ancient, and most prominent, visible structures on the other terrestrial planets and moons have vanished on the Earth. Only with the use of techniques like magnetics and gravity is it possible to see deeper within the crust. We identify possible impact structure(s) in the Arctic and Antarctic in this way, and discuss techniques that can be used to confirm or refute these identifications.

  20. Assessing the Impacts of forest degradation on water, energy, and carbon budgets in Amazon forest using the Functionally Assembled Terrestrial Ecosystem Simulator

    Science.gov (United States)

    Huang, M.; Xu, Y.; Longo, M.; Keller, M.; Knox, R. G.; Koven, C.; Fisher, R.

    2017-12-01

    Tropical forest degradation from logging, fire, and fragmentation not only alters carbon stocks and carbon fluxes, but also impacts physical land-surface properties such as albedo and roughness length. Such impacts are poorly quantified to date due to difficulties in accessing and maintaining observational infrastructures, and the lack of proper modeling tools for capturing the interactions among biophysical properties, ecosystem demography, and biogeochemical cycling in tropical forests. As a first step to address these limitations, we implemented a selective logging module into the Functional Assembled Terrestrial Ecosystem Simulator (FATES) and parameterized the model to reproduce the selective logging experiment at the Tapajos National Forest in Brazil. The model was spun up until it reached the steady state, and simulations with and without logging were compared with the eddy covariance flux towers located at the logged and intact sites. The sensitivity of simulated water, energy, and carbon fluxes to key plant functional traits (e.g. Vcmax and leaf longevity) were quantified by perturbing their values within their documented ranges. Our results suggest that the model can reproduce water and carbon fluxes in intact forests, although sensible heat fluxes were overestimated. The effects of logging intensity and techniques on fluxes were assessed by specifying different disturbance parameters in the models (e.g., size-dependent mortality rates associated with timber harvest, collateral damage, and mechanical damage for infrastructure construction). The model projections suggest that even though the degraded forests rapidly recover water and energy fluxes compared with old-growth forests, the recovery times for carbon stocks, forest structure and composition are much longer. In addition, the simulated recovery trajectories are highly dependent on choices of values for functional traits. Our study highlights the advantages of an Earth system modeling approach

  1. Application of terrestrial 'structure-from-motion' photogrammetry on a medium-size Arctic valley glacier: potential, accuracy and limitations

    Science.gov (United States)

    Hynek, Bernhard; Binder, Daniel; Boffi, Geo; Schöner, Wolfgang; Verhoeven, Geert

    2014-05-01

    Terrestrial photogrammetry was the standard method for mapping high mountain terrain in the early days of mountain cartography, until it was replaced by aerial photogrammetry and airborne laser scanning. Modern low-price digital single-lens reflex (DSLR) cameras and highly automatic and cheap digital computer vision software with automatic image matching and multiview-stereo routines suggest the rebirth of terrestrial photogrammetry, especially in remote regions, where airborne surveying methods are expensive due to high flight costs. Terrestrial photogrammetry and modern automated image matching is widely used in geodesy, however, its application in glaciology is still rare, especially for surveying ice bodies at the scale of some km², which is typical for valley glaciers. In August 2013 a terrestrial photogrammetric survey was carried out on Freya Glacier, a 6km² valley glacier next to Zackenberg Research Station in NE-Greenland, where a detailed glacier mass balance monitoring was initiated during the last IPY. Photos with a consumer grade digital camera (Nikon D7100) were taken from the ridges surrounding the glacier. To create a digital elevation model, the photos were processed with the software photoscan. A set of ~100 dGPS surveyed ground control points on the glacier surface was used to georeference and validate the final DEM. Aim of this study was to produce a high resolution and high accuracy DEM of the actual surface topography of the Freya glacier catchment with a novel approach and to explore the potential of modern low-cost terrestrial photogrammetry combined with state-of-the-art automated image matching and multiview-stereo routines for glacier monitoring and to communicate this powerful and cheap method within the environmental research and glacier monitoring community.

  2. Concrete structures under impact and impulsive loading

    International Nuclear Information System (INIS)

    Plauk, G.

    1982-05-01

    This book contains papers contributed to the RILEM/CEB/IABSE/IASS-Interassociation Symposium on 'Concrete Structures under Impact and Impulsive Loading'. The essential aim of this symposium is to provide an international forum for the exchange of information on existing and current research relating to impact problems as well as to identify areas to which further research activities should be directed. The subject of the symposium is far ranging. Fifty five papers were proposed and arranged in six technical sessions, a task which sometimes posed difficulties for the Organization Committee and the Advisory Group, because some of the papers touched several topics and were difficult to integrate. However, we are confident that these minor difficulties were solved to the satisfaction of everyone involved. Each session of the symposium is devoted to a major subject area and introduced by a distinguished Introductory Reporter. The large international attendance, some 21 countries are represented, and the large number of excellent papers will certainly produce a lively discussion after each session and thus help to further close the gaps in our knowledge about the behaviour of structures and materials under impact and impulsive loading. (orig./RW)

  3. Terrestrial planet formation.

    Science.gov (United States)

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  4. Concrete structures under impact loading: general aspects

    Directory of Open Access Journals (Sweden)

    Cornelia Baeră

    2016-09-01

    Full Text Available Dynamic loading conditions distress the structural integrity of a structure differently than the static ones. Such actions transfer high rate strains and instant energy waves to the structure, inducing the possibility of imminent collapse and casualties as a direct consequence. In the latest years, considering the dramatic increase of terrorist threats and global warming, the structural safety criteria imply more than ever the need to withstand this kind of loading (e.g., missiles and blast, projectiles, strong winds, tornados and earthquakes in addition to the static ones. The aim of this paper is to provide a general overview with regard to impact loading in terms of defining the phenomenon from physical and mechanical perspective, its complex local or global effect on the targeted structure, relevant material characteristics, main research approaches, namely theoretical studies and experimental procedures developed for improving the predictability of the dynamic loads and their effects. New directions in developing superior cementitious composites, with better characteristics in terms of dynamic loading performance are also emphasized.

  5. Histories of terrestrial planets

    International Nuclear Information System (INIS)

    Benes, K.

    1981-01-01

    The uneven historical development of terrestrial planets - Mercury, Venus, Earth, Moon and Mars - is probably due to the differences in their size, weight and rotational dynamics in association with the internal planet structure, their distance from the Sun, etc. A systematic study of extraterrestrial planets showed that the time span of internal activity was not the same for all bodies. It is assumed that the initial history of all terrestrial planets was marked with catastrophic events connected with the overall dynamic development of the solar system. In view of the fact that the cores of small terrestrial bodies cooled quicker, their geological development almost stagnated after two or three thousand million years. This is what probably happened to the Mercury and the Moon as well as the Mars. Therefore, traces of previous catastrophic events were preserved on the surface of the planets. On the other hand, the Earth is the most metamorphosed terrestrial planet and compared to the other planets appears to be atypical. Its biosphere is significantly developed as well as the other shell components, its hydrosphere and atmosphere, and its crust is considerably differentiated. (J.P.)

  6. Terrestrial Zone Exoplanets and Life

    Science.gov (United States)

    Matthews, Brenda

    2018-01-01

    One of the most exciting results from ALMA has been the detection of significant substructure within protoplanetary disks that can be linked to planet formation processes. For the first time, we are able to observe the process of assembly of material into larger bodies within such disks. It is not possible, however, for ALMA to probe the growth of planets in protoplanetary disks at small radii, i.e., in the terrestrial zone, where we expect rocky terrestrial planets to form. In this regime, the optical depths prohibit observation at the high frequencies observed by ALMA. To probe the effects of planet building processes and detect telltale gaps and signatures of planetary mass bodies at such small separations from the parent star, we require a facility of superior resolution and sensitivity at lower frequencies. The ngVLA is just such a facility. We will present the fundamental science that will be enabled by the ngVLA in protoplanetary disk structure and the formation of planets. In addition, we will discuss the potential for an ngVLA facility to detect the molecules that are the building blocks of life, reaching limits well beyond those reachable with the current generation of telescopes, and also to determine whether such planets will be habitable based on studies of the impact of stars on their nearest planetary neighbours.

  7. Impact effects in thin-walled structures

    International Nuclear Information System (INIS)

    Zukas, J.A.; Gaskill, B.

    1996-01-01

    A key parameter in the design of protective structures is the critical impact velocity, also known as the ballistic limit. This is the velocity below which a striker will fail to penetrate a barrier or some protective device. For strikers with regular shapes, such as cylinders (long and short), spheres and cones, analytical and empirical formulations for the determination of a ballistic limit exist at impact velocities ranging from 250 m/s to 6 km/s or higher. For non-standard shapes, two- and three-dimensional wave propagation codes (hydrocodes) can be valuable adjuncts to experiments in ballistic limit determinations. This is illustrated with the help of the ZeuS code in determining the ballistic limit of a short, tubular projectile striking a thin aluminum barrier and contrasting it to the value of the ballistic limit of a spherical projectile of equal mass against the same target. Several interesting features of the debris cloud generated by a tubular projectile striking a Whipple shield at hypervelocity are also pointed out. The paper concludes with a consideration of hydrodynamic ram effects in fluid-filled thin-walled structures. Where possible, comparisons are made of computed results with experimental data

  8. The Guarda structure (Portugal): Impact structure or not? Microstructural studies of Quartz, Zircon and Monazite

    NARCIS (Netherlands)

    Zalinge, M.E. van; Hamers, M.F.; Drury, M.R.

    2012-01-01

    The Guarda Structure in north-eastern Portugal has been proposed as a potential impact structure. We have studied the structure in detail, but no field or microscopic evidence has been found to support the impact hypothesis

  9. Geophysical characterization of the Chicxulub impact structure

    Science.gov (United States)

    Gulick, S. P.; Christeson, G. L.; Barton, P. J.; Grieve, R. A.; Morgan, J. V.; Fucugauchi, J. U.

    2013-05-01

    The Chicxulub impact structure, conclusively linked to the 65.5 Ma mass extinction, includes three sets of inward dipping, ring faults, between 70 and 130 km radially with a topographically elevated inner rim, at the inner edge of these faults except in the northeast where such a rim is absent. Slump blocks offset by large faults result in a terrace zone, that steps down from the inner rim into the annular trough. The inner blocks underlie the peak ring --an internal topographic ring of topography that exhibits variable relief due to target asymmetries and bounds the coherent melt sheet within the central basin. Impact breccias lie within the annular trough above the slump blocks and proximal ejecta and within the central basin above the melt sheet. Beneath the melt sheet is the top of the central uplift, displaced by >10 km vertically, and an upwarped Moho, displaced by 1-2 km. These interpretations and hydrocode models support the following working hypothesis for the formation of Chicxulub: a 50 km radius transient cavity, lined with melt and impact breccia, formed within 10s of seconds of the 65.5 Ma impact and within minutes, weakened rebounding crust rose above kilometers above the surface, the transient crater rim underwent localized, brittle deformation and collapsed into large slump blocks resulting in a inner rim being preserved 70-85 km from crater center, and ring faults forming farther outwards. The overheightened central uplift of weakened crust collapsed outwards forming the peak ring, and buried the inner slump blocks. Most impact melt that lined the transient cavity was transported on top of the central uplift, ultimately emplaced as a coherent <3-km thick melt sheet that shallows within the inner regions of the peak ring. Smaller pockets of melt flowed into the annular trough. During and likely for sometime after these events, slope collapse, proximal ejecta, ground surge, and tsunami waves infilled the annular trough with sediments up to 3 km

  10. Potential impacts of radon, terrestrial gamma and cosmic rays on childhood leukemia in France: a quantitative risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, Olivier [French Institute for Radiological Protection and Nuclear Safety, Radiobiology and Epidemiology Department, IRSN, PRP-HOM, SRBE, LEPID, Fontenay aux Roses (France); University of California, Irvine, Department of Population Health and Disease Prevention, Irvine, CA (United States); Ancelet, Sophie; Laurier, Dominique [French Institute for Radiological Protection and Nuclear Safety, Radiobiology and Epidemiology Department, IRSN, PRP-HOM, SRBE, LEPID, Fontenay aux Roses (France); Richardson, David B. [University of North Carolina at Chapel Hill, Department of Epidemiology, School of Public Health, Chapel Hill, NC (United States); Hemon, Denis; Demoury, Claire; Clavel, Jacqueline [Inserm, CESP Center for Research in Epidemiology and Population Health, U1018, Environmental Epidemiology of Cancer Team, Villejuif (France); Paris-Sud University, UMRS 1018, Villejuif (France); Ielsch, Geraldine [French Institute for Radiological Protection and Nuclear Safety, Assessment Unit for Risks Related to Natural Radioactivity, IRSN, PRP-DGE, SEDRAN, BRN, Fontenay aux Roses (France)

    2013-05-15

    Previous epidemiological studies and quantitative risk assessments (QRA) have suggested that natural background radiation may be a cause of childhood leukemia. The present work uses a QRA approach to predict the excess risk of childhood leukemia in France related to three components of natural radiation: radon, cosmic rays and terrestrial gamma rays, using excess relative and absolute risk models proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Both models were developed from the Life Span Study (LSS) of Japanese A-bomb survivors. Previous risk assessments were extended by considering uncertainties in radiation-related leukemia risk model parameters as part of this process, within a Bayesian framework. Estimated red bone marrow doses cumulated during childhood by the average French child due to radon, terrestrial gamma and cosmic rays are 4.4, 7.5 and 4.3 mSv, respectively. The excess fractions of cases (expressed as percentages) associated with these sources of natural radiation are 20 % [95 % credible interval (CI) 0-68 %] and 4 % (95 % CI 0-11 %) under the excess relative and excess absolute risk models, respectively. The large CIs, as well as the different point estimates obtained under these two models, highlight the uncertainties in predictions of radiation-related childhood leukemia risks. These results are only valid provided that models developed from the LSS can be transferred to the population of French children and to chronic natural radiation exposures, and must be considered in view of the currently limited knowledge concerning other potential risk factors for childhood leukemia. Last, they emphasize the need for further epidemiological investigations of the effects of natural radiation on childhood leukemia to reduce uncertainties and help refine radiation protection standards. (orig.)

  11. Potential impacts of radon, terrestrial gamma and cosmic rays on childhood leukemia in France: a quantitative risk assessment

    International Nuclear Information System (INIS)

    Laurent, Olivier; Ancelet, Sophie; Laurier, Dominique; Richardson, David B.; Hemon, Denis; Demoury, Claire; Clavel, Jacqueline; Ielsch, Geraldine

    2013-01-01

    Previous epidemiological studies and quantitative risk assessments (QRA) have suggested that natural background radiation may be a cause of childhood leukemia. The present work uses a QRA approach to predict the excess risk of childhood leukemia in France related to three components of natural radiation: radon, cosmic rays and terrestrial gamma rays, using excess relative and absolute risk models proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Both models were developed from the Life Span Study (LSS) of Japanese A-bomb survivors. Previous risk assessments were extended by considering uncertainties in radiation-related leukemia risk model parameters as part of this process, within a Bayesian framework. Estimated red bone marrow doses cumulated during childhood by the average French child due to radon, terrestrial gamma and cosmic rays are 4.4, 7.5 and 4.3 mSv, respectively. The excess fractions of cases (expressed as percentages) associated with these sources of natural radiation are 20 % [95 % credible interval (CI) 0-68 %] and 4 % (95 % CI 0-11 %) under the excess relative and excess absolute risk models, respectively. The large CIs, as well as the different point estimates obtained under these two models, highlight the uncertainties in predictions of radiation-related childhood leukemia risks. These results are only valid provided that models developed from the LSS can be transferred to the population of French children and to chronic natural radiation exposures, and must be considered in view of the currently limited knowledge concerning other potential risk factors for childhood leukemia. Last, they emphasize the need for further epidemiological investigations of the effects of natural radiation on childhood leukemia to reduce uncertainties and help refine radiation protection standards. (orig.)

  12. Terrestrial ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The main effort of the Terrestrial Ecology Division has been redirected to a comprehensive study of the Espiritu Santo Drainage Basin located in northeastern Puerto Rico. The general objective are to provide baseline ecological data for future environmental assessment studies at the local and regional levels, and to provide through an ecosystem approach data for the development of management alternatives for the wise utilization of energy, water, and land resources. The interrelationships among climate, vegetation, soils, and man, and their combined influence upon the hydrologic cycle will be described and evaluated. Environmental management involves planning and decision making, and both require an adequate data base. At present, little is known about the interworkings of a complete, integrated system such as a drainage basin. A literature survey of the main research areas confirmed that, although many individual ecologically oriented studies have been carried out in a tropical environment, few if any provide the data base required for environmental management. In view of rapidly changing socio-economic conditions and natural resources limitations, management urgently requires data from these systems: physical (climatological), biological, and cultural. This integrated drainage basin study has been designed to provide such data. The scope of this program covers the hydrologic cycle as it is affected by the interactions of the physical, biological, and cultural systems

  13. Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

    Science.gov (United States)

    Hauptmann, Aviaja L.; Markussen, Thor N.; Stibal, Marek; Olsen, Nikoline S.; Elberling, Bo; Bælum, Jacob; Sicheritz-Pontén, Thomas; Jacobsen, Carsten S.

    2016-01-01

    Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns. PMID:27708629

  14. Upstream freshwater and terrestrial sources are differentially reflected in the bacterial community structure along a small Arctic river and its estuary

    Directory of Open Access Journals (Sweden)

    Aviaja Lyberth Hauptmann

    2016-09-01

    Full Text Available Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N. Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns.

  15. Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Croft, Holly; Gonsamo, Alemu; Luo, Xiangzhong; Liu, Jane; Zheng, Ting; Liu, Ronggao; Liu, Yang

    2017-11-01

    The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2-induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003-2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N-constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000-2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon-water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

  16. Knottin cyclization: impact on structure and dynamics

    Directory of Open Access Journals (Sweden)

    Gracy Jérôme

    2008-12-01

    Full Text Available Abstract Background Present in various species, the knottins (also referred to as inhibitor cystine knots constitute a group of extremely stable miniproteins with a plethora of biological activities. Owing to their small size and their high stability, knottins are considered as excellent leads or scaffolds in drug design. Two knottin families contain macrocyclic compounds, namely the cyclotides and the squash inhibitors. The cyclotide family nearly exclusively contains head-to-tail cyclized members. On the other hand, the squash family predominantly contains linear members. Head-to-tail cyclization is intuitively expected to improve bioactivities by increasing stability and lowering flexibility as well as sensitivity to proteolytic attack. Results In this paper, we report data on solution structure, thermal stability, and flexibility as inferred from NMR experiments and molecular dynamics simulations of a linear squash inhibitor EETI-II, a circular squash inhibitor MCoTI-II, and a linear analog lin-MCoTI. Strikingly, the head-to-tail linker in cyclic MCoTI-II is by far the most flexible region of all three compounds. Moreover, we show that cyclic and linear squash inhibitors do not display large differences in structure or flexibility in standard conditions, raising the question as to why few squash inhibitors have evolved into cyclic compounds. The simulations revealed however that the cyclization increases resistance to high temperatures by limiting structure unfolding. Conclusion In this work, we show that, in contrast to what could have been intuitively expected, cyclization of squash inhibitors does not provide clear stability or flexibility modification. Overall, our results suggest that, for squash inhibitors in standard conditions, the circularization impact might come from incorporation of an additional loop sequence, that can contribute to the miniprotein specificity and affinity, rather than from an increase in conformational rigidity

  17. Isotopic and anatomical evidence of an herbivorous diet in the Early Tertiary giant bird Gastornis. Implications for the structure of Paleocene terrestrial ecosystems

    Science.gov (United States)

    Angst, D.; Lécuyer, C.; Amiot, R.; Buffetaut, E.; Fourel, F.; Martineau, F.; Legendre, S.; Abourachid, A.; Herrel, A.

    2014-04-01

    The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on 13C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ13C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.

  18. Snow-avalanche impact craters in southern Norway: Their morphology and dynamics compared with small terrestrial meteorite craters

    Science.gov (United States)

    Matthews, John A.; Owen, Geraint; McEwen, Lindsey J.; Shakesby, Richard A.; Hill, Jennifer L.; Vater, Amber E.; Ratcliffe, Anna C.

    2017-11-01

    This regional inventory and study of a globally uncommon landform type reveals similarities in form and process between craters produced by snow-avalanche and meteorite impacts. Fifty-two snow-avalanche impact craters (mean diameter 85 m, range 10-185 m) were investigated through field research, aerial photographic interpretation and analysis of topographic maps. The craters are sited on valley bottoms or lake margins at the foot of steep avalanche paths (α = 28-59°), generally with an easterly aspect, where the slope of the final 200 m of the avalanche path (β) typically exceeds 15°. Crater diameter correlates with the area of the avalanche start zone, which points to snow-avalanche volume as the main control on crater size. Proximal erosional scars ('blast zones') up to 40 m high indicate up-range ejection of material from the crater, assisted by air-launch of the avalanches and impulse waves generated by their impact into water-filled craters. Formation of distal mounds up to 12 m high of variable shape is favoured by more dispersed down-range deposition of ejecta. Key to the development of snow-avalanche impact craters is the repeated occurrence of topographically-focused snow avalanches that impact with a steep angle on unconsolidated sediment. Secondary craters or pits, a few metres in diameter, are attributed to the impact of individual boulders or smaller bodies of snow ejected from the main avalanche. The process of crater formation by low-density, low-velocity, large-volume snow flows occurring as multiple events is broadly comparable with cratering by single-event, high-density, high-velocity, small-volume projectiles such as small meteorites. Simple comparative modelling of snow-avalanche events associated with a crater of average size (diameter 85 m) indicates that the kinetic energy of a single snow-avalanche impact event is two orders of magnitude less than that of a single meteorite-impact event capable of producing a crater of similar size

  19. Impact processes, permafrost dynamics, and climate and environmental variability in the terrestrial Arctic as inferred from the unique 3.6 Myr record of Lake El'gygytgyn, Far East Russia - A review

    Science.gov (United States)

    Wennrich, Volker; Andreev, Andrei A.; Tarasov, Pavel E.; Fedorov, Grigory; Zhao, Wenwei; Gebhardt, Catalina A.; Meyer-Jacob, Carsten; Snyder, Jeffrey A.; Nowaczyk, Norbert R.; Schwamborn, Georg; Chapligin, Bernhard; Anderson, Patricia M.; Lozhkin, Anatoly V.; Minyuk, Pavel S.; Koeberl, Christian; Melles, Martin

    2016-09-01

    Lake El'gygytgyn in Far East Russia is a 3.6 Myr old impact crater lake. Located in an area that has never been affected by Cenozoic glaciations nor desiccation, the unique sediment record of the lake represents the longest continuous sediment archive of the terrestrial Arctic. The surrounding crater is the only impact structure on Earth developed in mostly acid volcanic rocks. Recent studies on the impactite, permafrost, and sediment sequences recovered within the framework of the ICDP "El'gygytgyn Drilling Project" and multiple pre-site surveys yielded new insight into the bedrock origin and cratering processes as well as permafrost dynamics and the climate and environmental history of the terrestrial Arctic back to the mid-Pliocene. Results from the impact rock section recovered during the deep drilling clearly confirm the impact genesis of the El'gygytgyn crater, but indicate an only very reduced fallback impactite sequence without larger coherent melt bodies. Isotope and element data of impact melt samples indicate a F-type asteroid of mixed composition or an ordinary chondrite as the likely impactor. The impact event caused a long-lasting hydrothermal activity in the crater that is assumed to have persisted for c. 300 kyr. Geochemical and microbial analyses of the permafrost core indicate a subaquatic formation of the lower part during lake-level highstand, but a subaerial genesis of the upper part after a lake-level drop after the Allerød. The isotope signal and ion compositions of ground ice is overprinted by several thaw-freeze cycles due to variations in the talik underneath the lake. Modeling results suggest a modern permafrost thickness in the crater of c. 340 m, and further confirm a pervasive character of the talik below Lake El'gygytgyn. The lake sediment sequences shed new leight into the Pliocene and Pleistocene climate and environmental evolution of the Arctic. During the mid-Pliocene, significantly warmer and wetter climatic conditions in

  20. Using the Terrestrial Observation and Prediction System (TOPS) to Analyze Impacts of Climate Change on Ecosystems within Northern California Climate Regions

    Science.gov (United States)

    Pitts, K.; Little, M.; Loewenstein, M.; Iraci, L. T.; Milesi, C.; Schmidt, C.; Skiles, J. W.

    2011-12-01

    The projected impacts of climate change on Northern California ecosystems using model outputs from the Terrestrial Observation and Prediction System (TOPS) for the period 1950-2099 based on 1km downscaled climate data from the Geophysical Fluid Dynamics Laboratory (GFDL) model are analyzed in this study. The impacts are analyzed for the Special Report Emissions Scenarios (SRES) A1B and A2, both maintaining present levels of urbanization constant and under projected urban expansion. The analysis is in support of the Climate Adaptation Science Investigation at NASA Ames Research Center. A statistical analysis is completed for time series of temperature, precipitation, gross primary productivity (GPP), evapotranspiration, soil runoff, and vapor pressure deficit. Trends produced from this analysis show that increases in maximum and minimum temperatures lead to declines in peak GPP, length of growing seasons, and overall declines in runoff within the watershed. For Northern California, GPP is projected under the A2 scenario to decrease by 18-25% by the 2090 decade as compared to the 2000 decade. These trends indicate a higher risk to crop production and other ecosystem services, as conditions would be less hospitable to vegetation growth. The increase in dried out vegetation would then lead to a higher risk of wildfire and mudslides in the mountainous regions.

  1. Assessment of Containment Structures Against Missile Impact Threats

    Institute of Scientific and Technical Information of China (English)

    LI Q M

    2006-01-01

    In order to ensure the highest safety requirements,nuclear power plant structures (the containment structures,the fuel storages and transportation systems) should be assessed against all possible internal and external impact threats.The internal impact threats include kinetic missiles generated by the failure of high pressure vessels and pipes,the failure of high speed rotating machineries and accidental drops.The external impact threats may come from airborne missiles,aircraft impact,explosion blast and fragments.The impact effects of these threats on concrete and steel structures in a nuclear power plant are discussed.Methods and procedures for the impact assessment of nuclear power plants are introduced.Recent studies on penetration and perforation mechanics as well as progresses on dynamic properties of concrete-like materials are presented to increase the understanding of the impact effects on concrete containment structures.

  2. Low Velocity Impact Properties of Aluminum Foam Sandwich Structural Composite

    Directory of Open Access Journals (Sweden)

    ZHAO Jin-hua

    2018-01-01

    Full Text Available Sandwich structural composites were prepared by aluminum foam as core materials with basalt fiber(BF and ultra-high molecular weight polyethylene(UHMWPE fiber composite as faceplate. The effect of factors of different fiber type faceplates, fabric layer design and the thickness of the corematerials on the impact properties and damage mode of aluminum foam sandwich structure was studied. The impact properties were also analyzed to compare with aluminum honeycomb sandwich structure. The results show that BF/aluminum foam sandwich structural composites has bigger impact damage load than UHMWPE/aluminum foam sandwich structure, but less impact displacement and energy absorption. The inter-layer hybrid fabric design of BF and UHMWPE has higher impact load and energy absorption than the overlay hybrid fabric design faceplate sandwich structure. With the increase of the thickness of aluminum foam,the impact load of the sandwich structure decreases, but the energy absorption increases. Aluminum foam sandwich structure has higher impact load than the aluminum honeycomb sandwich structure, but smaller damage energy absorption; the damage mode of aluminum foam core material is mainly the fracture at the impact area, while aluminum honeycomb core has obvious overall compression failure.

  3. The Impact of Structural Genomics: Expectations and Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Chandonia, John-Marc; Brenner, Steven E.

    2005-12-21

    Structural Genomics (SG) projects aim to expand our structural knowledge of biological macromolecules, while lowering the average costs of structure determination. We quantitatively analyzed the novelty, cost, and impact of structures solved by SG centers, and contrast these results with traditional structural biology. The first structure from a protein family is particularly important to reveal the fold and ancient relationships to other proteins. In the last year, approximately half of such structures were solved at a SG center rather than in a traditional laboratory. Furthermore, the cost of solving a structure at the most efficient U.S. center has now dropped to one-quarter the estimated cost of solving a structure by traditional methods. However, top structural biology laboratories are much more efficient than the average, and comparable to SG centers despite working on very challenging structures. Moreover, traditional structural biology papers are cited significantly more often, suggesting greater current impact.

  4. Structural Behavior Under Precision Impact Tests

    Science.gov (United States)

    1996-08-01

    ASPECTS OF IMPACT TESTING The problem of impact between two bodies has been studied extensively (for example, Eibl 1987, Feyerabend 1988, Krauthammer...Concrete for Hazard Protection, Edinburgh, Scotland, pp. 175-186. Feyerabend , M., 1988, "Der harte Querstoss auf Stützen aus Stahl und Stahlbeton

  5. The Surface of Venus is Saturated With Ancient Impact Structures, and its Plains are Marine Sediments

    Science.gov (United States)

    Hamilton, W. B.

    2009-05-01

    lander images; and widespread minor structures with neither terrestrial volcanic analogues nor plausible volcanic explanations. Broad tracts of polygonal reticulations 100 m to 5 km in diameter have dimensional and geometric terrestrial analogues in the polygonal faulting shown by 3-D reflection-seismic surveys of dewatered fine-grained sediments in marine basins. Impact-comminuted basaltic crust may dominate the fine sediment. Vast numbers of small low so-called shield volcanoes have geometric analogues in terrestrial mud volcanoes, not magmatic constructs. Less than half of the 1000 small misnamed pristine craters, the only venusian craters accepted by all as of impact origin, in fact are pristine. The rest are variably eroded, their craters partly filled by sediments that often display polygonal faulting, and their aprons partly covered by sediments of surrounding plains. All gradations are displayed between these structures and the more modified but otherwise similar structures from which they are arbitrarily and inconsistently separated. Lunar analogy dates the thousands of large venusian craters, 300-2000 km in rim diameter, as older than 3.8 Ga. Marine sedimentation began before late-stage accretion was complete. The nominally pristine craters are commonly assumed to be younger than 1 Ga but may go back to 3.8 Ga. Venusian oceans persisted long after that, without stillstands sufficient for development of global shorelines and shelves, before complete greenhouse evaporation, deep desiccation, and top-down metamorphism of sediments.

  6. Impacts of fire on nitrogen cycling in aquatic and terrestrial ecosystems in the Yukon-Kuskokwim River Delta, AK

    Science.gov (United States)

    Schade, J. D.; Jardine, L. E.; Bristol, E. M.; Navarro-Perez, E.; Melton, S.; Jimmie, J. A.; Natali, S.; Mann, P. J.; Holmes, R. M.

    2017-12-01

    Global climate change is having a disproportionate impact on northern high latitudes, including rapid increases in temperature, changes in precipitation, and increasing fire frequency and severity. Wildfires have been shown to strongly influence ecosystem processes through acceleration of permafrost thaw and increased nitrogen (N) availability, the effects of which may increase gaseous loss of carbon (C) to the atmosphere, increase primary production by alleviating N limitation, or both. The extent of these fire impacts has not been well-documented in the Arctic, particularly in areas of discontinuous permafrost. In 2015, the Yukon-Kuskokwim River Delta (YK Delta) in southwestern Alaska experienced the largest fire season in recorded history, providing an opportunity to study wildfire impacts on an area particularly vulnerable to permafrost thaw. Our objectives were to study the impacts of these fires on nitrogen availability in a range of land cover classes, including peat plateaus, channel fens, and aquatic ecosystems distributed across the landscapes. We sampled soils from several vegetation patches on burned and unburned peat plateaus, and soil and surface waters from fens, small ponds, and streams downslope of these sites. All water samples were filtered through GFF filters in the field. Soils were transported frozen to the Woods Hole Research Center and extracted in KCl. All water samples and extracts were analyzed for NH4 and NO3 concentrations. We found substantially higher concentrations of extractable NH4 in burned soils, but very little extractable NO3 in either burned or unburned soils. Water samples also showed higher NH4 in aquatic ecosystems in burned watersheds, but, in contrast to soils, showed relatively high NO3 concentrations, particularly in waters from lower landscape positions. Overall, aquatic ecosystems exhibited higher NO3: NH4 ratios than soil extractions, and increasing NO3: NH4 downslope. These results suggest significant export of

  7. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  8. The mutual impact of organizational culture and structure

    OpenAIRE

    Janićijević Nebojša

    2013-01-01

    This paper explores the relationship between the structure and culture of an organization. The starting assumption is that organizational structure and organizational culture impact each other, and that there is a causal relationship due to which the agreement of the two components of organization leads to better performance. First, the mechanism through which organizational culture impacts the design of organizational structures and the manner in which org...

  9. Terrestrial Analogs for Surface Properties Associated with Impact Cratering on the Moon - Self-secondary Impact Features at Kings Bowl, Idaho

    Science.gov (United States)

    Matiella Novak, M. A.; Zanetti, M.; Neish, C.; Kukko, A.; Fan, K.; Heldmann, J.; Hughes, S. S.

    2017-12-01

    The Kings Bowl (KB) eruptive fissure and lava field, located in the southern end of Craters of the Moon National Monument, Idaho, is an ideal location for planetary analogue field studies of surface properties related to volcanic and impact processes. Here we look at possible impact features present in the KB lava field near the main vent that resulted in squeeze-ups of molten lava from beneath a semi-solid lava lake crust. These may have been caused by the ejection of blocks during the phreatic eruption that formed the Kings Bowl pit, and their subsequent impact into a partially solidified lava pond. We compare and contrast these features with analogous self-secondary impact features, such as irregular, rimless secondary craters ("splash craters") observed in lunar impact melt deposits, to better understand how self-secondary impacts determine the surface properties of volcanic and impact crater terrains. We do this by analyzing field measurements of these features, as well as high-resolution DEM data collected through the Kinematic LiDAR System (KLS), both of which give us feature dimensions and distributions. We then compare these data with self-secondary impact features on the Moon and related surface roughness constrained through Lunar Reconnaissance Orbiter observations (Mini-RF and LROC NACs). Possible self-secondary impact features can be found in association with many lunar impact craters. These are formed when ballistic ejecta from the crater falls onto the ejecta blanket and melt surrounding the newly formed crater. Self-secondary impact features involving impact melt deposits are particularly useful to study because the visibly smooth melt texture serves to highlight the impact points in spacecraft imagery. The unusual morphology of some of these features imply that they formed when the melt had not yet completely solidified, strongly suggesting a source of impactors from the primary crater itself. We will also discuss ongoing efforts to integrate field

  10. IMPACT ASSESSMENT OF STRUCTURAL FLOOD MITIGATION MEASURES

    Directory of Open Access Journals (Sweden)

    ZVIJAKOVA LENKA

    2015-03-01

    Full Text Available The objective of the paper is to propose a methodology for assessing water constructions, which will allow impact assessment of water constructions on the environment and hence select the best option for the permission process. The result is “Guideline for environmental impact assessment of flood protection object”, which uses the method of UMRA (universal matrix of risk analysis, which is one of the methods of risk analysis proposed not only to enhance the transparency and sensitivity of the evaluation process, but also to cope with the requirements of the EIA system in the Slovakia and Europe Union.

  11. MODIS-derived terrestrial primary production [chapter 28

    Science.gov (United States)

    Maosheng Zhao; Steven Running; Faith Ann Heinsch; Ramakrishna Nemani

    2011-01-01

    Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of...

  12. The influence of food abundance, food dispersion and habitat structure on territory selection and size of an Afrotropical terrestrial insectivore

    Science.gov (United States)

    Stanley, Thomas R.; Newmark, William D.

    2015-01-01

    Most tropical insectivorous birds, unlike their temperate counterparts, hold and defend a feeding and breeding territory year-around. However, our understanding of ecological factors influencing territory selection and size in tropical insectivores is limited. Here we examine three prominent hypotheses relating food abundance, food dispersion (spatial arrangement of food items), and habitat structure to territoriality in the Usambara Thrush Turdus roehli. We first compared leaf-litter macro-invertebrate abundance and dispersion, and habitat structure between territories and random sites. We then examined the relation between these same ecological factors and territory size. Invertebrate abundance and dispersion were sparsely and evenly distributed across our study system and did not vary between territories and random sites. In contrast, habitat structure did vary between territories and random sites indicating the Usambara Thrush selects territories with open understorey and closed overstorey habitat. Invertebrate abundance and dispersion within territories of the Usambara Thrush were not associated with habitat structure. We believe the most likely explanation for the Usambara Thrush’s preference for open understorey and closed overstorey habitat relates to foraging behavior. Using information-theoretic model selection we found that invertebrate abundance was the highest-ranked predictor of territory size and was inversely related, consistent with food value theory of territoriality.

  13. Impact of 3D Canopy Structure on Remote Sensing Vegetation Index and Solar Induced Chlorophyll Fluorescence

    Science.gov (United States)

    Zeng, Y.; Berry, J. A.; Jing, L.; Qinhuo, L.

    2017-12-01

    Terrestrial ecosystem plays a critical role in removing CO2 from atmosphere by photosynthesis. Remote sensing provides a possible way to monitor the Gross Primary Production (GPP) at the global scale. Vegetation Indices (VI), e.g., NDVI and NIRv, and Solar Induced Fluorescence (SIF) have been widely used as a proxy for GPP, while the impact of 3D canopy structure on VI and SIF has not be comprehensively studied yet. In this research, firstly, a unified radiative transfer model for visible/near-infrared reflectance and solar induced chlorophyll fluorescence has been developed based on recollision probability and directional escape probability. Then, the impact of view angles, solar angles, weather conditions, leaf area index, and multi-layer leaf angle distribution (LAD) on VI and SIF has been studied. Results suggest that canopy structure plays a critical role in distorting pixel-scale remote sensing signal from leaf-scale scattering. In thin canopy, LAD affects both of the remote sensing estimated GPP and real GPP, while in dense canopy, SIF variations are mainly due to canopy structure, instead of just due to physiology. At the microscale, leaf angle reflects the plant strategy to light on the photosynthesis efficiency, and at the macroscale, a priori knowledge of leaf angle distribution for specific species can improve the global GPP estimation by remote sensing.

  14. Structured ion impact: Doubly differential cross sections

    International Nuclear Information System (INIS)

    DuBois, R.D.

    1987-01-01

    The electron emission in coincidence with a projectile that has been ionized has been measured, thus making it possible to separate and identify electrons resulting from these various mechanisms. In 1985, coincidence doubly differential cross sections were measured for 400 to 750 keV/atomic mass unit (amu) He + impact on He, Ne, Ar, Kr, and H 2 O. Cross sections were measured for selected angles and for electron energies ranging from 10 to 1000 eV. Because of the coincidence mode of measurement, the total electron emission was subdivided into its target emission and its projectile emission components. The most interesting findings were that target ionization does not account for the electron emission spectrum at lower electron energies. A sizable percentage of these low-energy electrons were shown to originate as a result of simultaneous projectile/target ionizations. Similar features were observed for all targets and impact energies that were studied

  15. Eco-toxicological impact of “metals” on the aquatic and terrestrial ecosystem: A comparison between eight different methodologies for Life Cycle Impact Assessment (LCIA)

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Christensen, Per; Schmidt, Jannick Andresen

    2011-01-01

    the presence of high uncertainties in the process, in particular when the analysis focuses on metals emissions. Metals are diverse inorganic substances relevant for their characteristic environmental chemistry, their high persistency into the environment and their toxicity at even low environmental...... a contribution analysis at two levels: general and specific. Results show that there is poor agreement between methods in the determination of the total eco-toxic impact attributable to metals, and in defining which metal provokes the highest eco-toxic impact per unitary emission. Furthermore......, the characterization phase is critical in determining the disagreement between methods. However, some similarities were found: there is the tendency in most methods to associate the largest share of the total eco-toxicological impacts to metals. Theoretical and practical differences between methods are discussed...

  16. Structural design for aircraft impact loading

    International Nuclear Information System (INIS)

    Schmidt, R.; Heckhausen, H.; Chen, C.; Rieck, P.J.; Lemons, G.W.

    1977-01-01

    The distribution of military aircraft and proximity to commercial air routes requires the analysis of aircraft impact effect on nuclear power plant facilities in Europe. The typical approach on recent projects has been the hardening of safety-related buildings and/or protection of redundant safety-related equipment through separation. The 'hardened-building' approach has led to the consideration of severe shock and vibration caused by the aircraft impact and development of corresponding floor response spectra for component design. Conservatively calculated loads resulting from these are in some cases quite severe. The reactor auxiliary system building (Soft Shell Hardcore design) allows a more defensive alternate in the form of a partially softened design. In this approach the equipment layout is arranged such that equipment performing either safety functions or having the potential for significant release of radioactivity (upon destruction) is located in the central area of the plant and is enclosed in thick concrete walls for shielding and protection purposes. The non-safety class equipment is arranged in the area peripheral to the hardened central area and enclosed in thin concrete walls. Since the kinetic energy of the impacting aircraft is absorbed by the collapsed thin walls and ceilings, the vibrational effect on the safety class equipment is drastically reduced. In order to achieve the objective of absorbing high kinetic energy and yet reduce the shock and vibration effects, the softened exterior walls require low resistance and high ductility. This investigation determines the feasibility of two 0.5 m thick walls of the Soft Shell with the simplest possible mathematical model. (Auth.)

  17. Inverse Analysis of Cavitation Impact Phenomena on Structures

    National Research Council Canada - National Science Library

    Lambrakos, S. G; Tran, N. E

    2007-01-01

    A general methodology is presented for in situ detection of cavitation impact phenomena on structures based on inverse analysis of luminescent emissions resulting from the collapsing of bubbles onto surfaces...

  18. Impact of the structural changes on the nuclear safety

    International Nuclear Information System (INIS)

    Ziakova, M.

    2005-01-01

    In this presentation author deals with impact of the structural changes (privatization of the Slovenske Elektrarne, a.s.) and new Atomic law (541/2004 Coll. Laws) on the nuclear safety in the Slovak Republic.

  19. Aircraft impact on nuclear power plants concrete structures

    International Nuclear Information System (INIS)

    Coombs, R.F.; Barbosa, L.C.B.; Santos, S.H.C.

    1980-01-01

    A summary about the procedures for the analysis of aircraft on concrete structures, aiming to emphasize the aspects related to the nuclear power plants safety, is presented. The impact force is determined by the Riera model. The effect of this impact force on the concrete structures is presented, showing the advantages to use nonlinear behaviour in the concrete submitted to short loads. The simplifications used are shown through a verification example of the nuclear reactor concrete shielding. (E.G.) [pt

  20. Structural impact detection with vibro-haptic interfaces

    Science.gov (United States)

    Jung, Hwee-Kwon; Park, Gyuhae; Todd, Michael D.

    2016-07-01

    This paper presents a new sensing paradigm for structural impact detection using vibro-haptic interfaces. The goal of this study is to allow humans to ‘feel’ structural responses (impact, shape changes, and damage) and eventually determine health conditions of a structure. The target applications for this study are aerospace structures, in particular, airplane wings. Both hardware and software components are developed to realize the vibro-haptic-based impact detection system. First, L-shape piezoelectric sensor arrays are deployed to measure the acoustic emission data generated by impacts on a wing. Unique haptic signals are then generated by processing the measured acoustic emission data. These haptic signals are wirelessly transmitted to human arms, and with vibro-haptic interface, human pilots could identify impact location, intensity and possibility of subsequent damage initiation. With the haptic interface, the experimental results demonstrate that human could correctly identify such events, while reducing false indications on structural conditions by capitalizing on human’s classification capability. Several important aspects of this study, including development of haptic interfaces, design of optimal human training strategies, and extension of the haptic capability into structural impact detection are summarized in this paper.

  1. Terrestrial Turtle Habitats Potentially Impacted

    National Research Council Canada - National Science Library

    Dickerson, Dena

    1999-01-01

    .... This group includes the tortoises and box turtles with two species Federally threatened and three species having protection in at least one state. Three of these protected species are associated with environmental issues at 21 USACE projects from 5 USACE Districts.

  2. The impact of financial crisis on portuguese firms' capital structure

    OpenAIRE

    Lemos, Jéssica Andreia Rocha

    2017-01-01

    G01, G32 This study aims to verify the impacts of financial crises in the capital structure for Portuguese companies. The purpose is to study different firm-specific determinants of a sample of general PSI Portuguese listed firms at the Euronext Lisbon stock exchange, during the recent crises that endured from 2011 until 2013 and test the impacts on short and long-term debt. In order to test the changes/impacts on Portuguese firms’ capital structure, the most important theor...

  3. Revisiting the West Clearwater Lake Impact Structure, Canada

    Science.gov (United States)

    Osinski, G. R.; Brunner, A.; Collins, G.; Cohen, B. A.; Coulter, A.; Elphic, R.; Grieve, R. A. F.; Hodges, K.; Horne, A.; Kerrigan, M.

    2015-01-01

    The West and East Clearwater Lake impact structures are two of the most distinctive and recognizable impact structures on Earth. Known regionally as the "Clearwater Lake Complex", these structures are located in northern Quebec, Canada (56 deg 10 N, 74 deg 20 W) approximately 125 km east of Hudson Bay. The currently accepted diameters are 36 km and 26 km for the West and East structures, respectively. Long thought to represent a rare example of a double impact, recent age dating has called this into question with ages of approximately 286 Ma and approximately 460-470 Ma being proposed for the West and East structures, respectively. Relatively little is known about the East Clearwater Lake structure. There is no surface exposure and what information there is comes from geophysics and two drill cores obtained in the 1960s. In contrast, the West Clearwater Lake structure is relatively well preserved with large ring of islands in the approximately 30 km diameter lake. Much of the work done on West Clearwater stems from field investigations carried out in 1977 driven by the Apollo program, with a focus on the impact melt rocks and other impactites, which are well exposed on the ring of islands. To our knowledge, the Clearwater Lake impact structures have not been the focus of detailed impact geology field investigations since the 1977 expedition and the only geological map that exists is from the 1960s and is at the reconnaissance level. Our knowledge of impact cratering processes have increased substantially since this time, as have the analytical techniques available for samples. This provided the motivation for a joint Canadian-US-UK expedition to the West Clearwater Lake impact structure in August and September 2015, under the auspices of the FINESSE (Field Investigations to Enable Solar System Science and Exploration) project, part of NASA's Solar System Exploration Research Virtual Institute (SSERVI). We focus here on the impactites of the West Clearwater Lake

  4. Governance structures impact on eHealth

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2015-01-01

    Background National eHealth implementation efforts need to move beyond the scope of making technology the primary focus and instead consider the broader spectrum of influences that can either hinder or facilitate eHealth adoption such as governance structures and policies. In this study, Denmark...... serves as an ideal candidate for further examination due to the country׳s rich history of intertwining events that have played an important role in the dynamic relationship between governance and eHealth success and failures. Methods A case study approach was used to gather a combination of primary...... and secondary data sources. All data collection was carried out through desk-research. Data collection relied on performing an extensive search of literature for relevant studies using combinations of keywords that reflected eHealth and governance-related topics. Inclusion and exclusion criteria׳s were applied...

  5. Chesapeake Bay impact structure: A blast from the past

    Science.gov (United States)

    Powars, David S.; Edwards, Lucy E.; Gohn, Gregory S.; Horton, J. Wright

    2015-10-28

    About 35 million years ago, a 2-mile-wide meteorite smashed into Earth in what is now the lower Chesapeake Bay in Virginia. The oceanic impact vaporized, melted, fractured, and displaced rocks and sediments and sent billions of tons of water, sediments, and rocks into the air. Glassy particles of solidified melt rock rained down as far away as Texas and the Caribbean. Large tsunamis affected most of the North Atlantic basin. The resulting impact structure is more than 53 miles wide and has a 23-mile-wide, filled central crater surrounded by collapsed sediments. Now buried by hundreds of feet of younger sediments, the Chesapeake Bay impact structure is among the 20 largest known impact structures on Earth.

  6. The mutual impact of organizational culture and structure

    Directory of Open Access Journals (Sweden)

    Janićijević Nebojša

    2013-01-01

    Full Text Available This paper explores the relationship between the structure and culture of an organization. The starting assumption is that organizational structure and organizational culture impact each other, and that there is a causal relationship due to which the agreement of the two components of organization leads to better performance. First, the mechanism through which organizational culture impacts the design of organizational structures and the manner in which organizational structure affects the maintenance, strengthening, or changing of organizational culture is explained at the conceptual level. Then, based on the known classifications of organizational structure and culture, they are put into a relationship of direct mutual interdependence. This is done by generating hypotheses about the agreement of particular types of organizational culture and particular types of organizational structure.

  7. Characterizing Terrestrial Exoplanets

    Science.gov (United States)

    Meadows, V. S.; Lustig-Yaeger, J.; Lincowski, A.; Arney, G. N.; Robinson, T. D.; Schwieterman, E. W.; Deming, L. D.; Tovar, G.

    2017-11-01

    We will provide an overview of the measurements, techniques, and upcoming missions required to characterize terrestrial planet environments and evolution, and search for signs of habitability and life.

  8. Assessing the performance of reinforced concrete structures under impact loads

    International Nuclear Information System (INIS)

    Sharma, Akanshu; Reddy, G.R.; Vaze, K.K.; Ozbolt, Josko; Hofmann, J.

    2011-01-01

    Reinforced concrete (RC) structures housing nuclear facilities must qualify against much stringent requirements of operating and accidental loads than conventional structures. One such accidental load that must be considered while assessing the performance of safety related RC structures is impact load. It is known that the behavior of concrete/reinforced concrete structures is strongly influenced by the loading rate. The RC structural members subjected to impact loads behave quite differently as compared to the same subjected to quasi-static loading due to the strain-rate influence on strength, stiffness, and ductility as well as to the activation of inertia forces. Moreover, for concrete structures, which exhibit damage and fracture phenomena, the failure mode and cracking pattern depend significantly on loading rate. In general, there is a tendency that with the increase of loading rate the failure mode changes from mode-I to mixed mode. In order to assess the performance of existing structures against impact loads that may be generated mainly due to man-made accidental conditions, it is important to have models that can realistically predict the impact behavior of concrete structures. The present paper focuses on a relatively new approach for 3D finite element analysis of RC structures under impact loads. The approach uses rate sensitive micro-plane model as constitutive law for concrete, while the strain-rate influence is captured by the activation energy. Inertia forces are implicitly accounted for through dynamic finite element analysis. It is shown with the help of different examples that the approach can very well simulate the behavior of RC structural elements under high rate loading. (author)

  9. Basic concept on the responses of structural members and structures under impact or impulsive loadings

    International Nuclear Information System (INIS)

    Takeda, J.I.; Tachikawa, H.; Fujimoto, K.

    1982-01-01

    The responses of structural members and structures subjected to impact or impulsive loadings are generated by the interaction between acting bodies and structures, and the interaction is affected by many factors, e.g. the relations of masses, sizes, rigidities, etc. between acting bodies and structures and especially by relative velocity. The development of the responses of structural members and structures are controlled by the constitutive equations and failure criteria of constituent materials, the relationships of cowork system between the constituent materials and existing stress waves. Furthermore, the first two are influenced by rate effects and they all widely change by the speeds of impact and impulsive loadings. This paper deals with the physical meaning of the responses of structures under impact and impulsive loadings. (orig.) [de

  10. A Comparative Analysis of the Magnetic Field Signals over Impact Structures on the Earth, Mars and the Moon

    Science.gov (United States)

    Isac, Anca; Mandea, Mioara; Purucker, Michael; Langlais, Benoit

    2015-01-01

    An improved description of magnetic fields of terrestrial bodies has been obtained from recent space missions, leading to a better characterization of the internal fields including those of crustal origin. One of the striking differences in their crustal magnetic field is the signature of large impact craters. A comparative analysis of the magnetic characteristics of these structures can shed light on the history of their respective planetary-scale magnetic dynamos. This has motivated us to identify impact craters and basins, first by their quasi-circular features from the most recent and detailed topographic maps and then from available global magnetic field maps. We have examined the magnetic field observed above 27 complex craters on the Earth, 34 impact basins on Mars and 37 impact basins on the Moon. For the first time, systematic trends in the amplitude and frequency of the magnetic patterns, inside and outside of these structures are observed for all three bodies. The demagnetization effects due to the impact shock wave and excavation processes have been evaluated applying the Equivalent Source Dipole forward modeling approach. The main characteristics of the selected impact craters are shown. The trends in their magnetic signatures are indicated, which are related to the presence or absence of a planetary-scale dynamo at the time of their formation and to impact processes. The low magnetic field intensity at center can be accepted as the prime characteristic of a hypervelocity impact and strongly associated with the mechanics of impact crater formation. In the presence of an active internal field, the process of demagnetization due to the shock impact is associated with post-impact remagnetization processes, generating a more complex magnetic signature.

  11. V. Terrestrial vertebrates

    Science.gov (United States)

    Dean Pearson; Deborah Finch

    2011-01-01

    Within the Interior West, terrestrial vertebrates do not represent a large number of invasive species relative to invasive weeds, aquatic vertebrates, and invertebrates. However, several invasive terrestrial vertebrate species do cause substantial economic and ecological damage in the U.S. and in this region (Pimental 2000, 2007; Bergman and others 2002; Finch and...

  12. Quantification of anthropogenic impact on groundwater-dependent terrestrial ecosystem using geochemical and isotope tools combined with 3-D flow and transport modelling

    Science.gov (United States)

    Zurek, A. J.; Witczak, S.; Dulinski, M.; Wachniew, P.; Rozanski, K.; Kania, J.; Postawa, A.; Karczewski, J.; Moscicki, W. J.

    2015-02-01

    Groundwater-dependent ecosystems (GDEs) have important functions in all climatic zones as they contribute to biological and landscape diversity and provide important economic and social services. Steadily growing anthropogenic pressure on groundwater resources creates a conflict situation between nature and man which are competing for clean and safe sources of water. Such conflicts are particularly noticeable in GDEs located in densely populated regions. A dedicated study was launched in 2010 with the main aim to better understand the functioning of a groundwater-dependent terrestrial ecosystem (GDTE) located in southern Poland. The GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Błoto fen). It relies mostly on groundwater from the shallow Quaternary aquifer and possibly from the deeper Neogene (Bogucice Sands) aquifer. In July 2009 a cluster of new pumping wells abstracting water from the Neogene aquifer was set up 1 km to the northern border of the fen. A conceptual model of the Wielkie Błoto fen area for the natural, pre-exploitation state and for the envisaged future status resulting from intense abstraction of groundwater through the new well field was developed. The main aim of the reported study was to probe the validity of the conceptual model and to quantify the expected anthropogenic impact on the studied GDTE. A wide range of research tools was used. The results obtained through combined geologic, geophysical, geochemical, hydrometric and isotope investigations provide strong evidence for the existence of upward seepage of groundwater from the deeper Neogene aquifer to the shallow Quaternary aquifer supporting the studied GDTE. Simulations of the groundwater flow field in the study area with the aid of a 3-D flow and transport model developed for Bogucice Sands (Neogene) aquifer and calibrated using environmental tracer data and observations of hydraulic head in three different locations on the study area

  13. Biodiversity, Community and Trophic Structure of the Suprabenthos of the Gulf of Cádiz-Guadalquivir Estuary Coupled System: Linking Pelagic-Benthic and Terrestrial-Marine Ecosystems.

    Science.gov (United States)

    Vilas, C.

    2016-02-01

    Suprabenthos biodiversity and species densities on both offshore and coastal systems are largely unknown. Main components like mysids, euphasiids or amphipods are omnivorous and constitute a major dietary component for many benthic and pelagic fishes, mammals, cephalopods and decapods. Despite their relevant ecological role linking pelagic-benthic food webs, suprabenthos have been chronically undersampled and their components underrepresented and underestimated in food web models. Many pelagic and demersal species of high commercial and ecological interest at the Gulf of Cádiz (GoC) feed at a bottom scattering layer identified from 0 to 200 m depth and up to 50 km from coast, related to the Guadalquivir Estuary (GE) influence coastal area, and present life history cycles based on a sequential use of habitats from GoC to GE nursery area, may be adapted to match the horizontal migrations of key suprabenthos prey species. In order to understand the ecological mechanisms through which the GE-GoC coupled ecosystem would influence the recruitment of these fishery resources, the suprabenthos was sampled by suprabenthic sldege (200 μm) from the shallow estuary to 75 m depth during June, August and November of 2013. We identified up to 300 species (H index 0.4-2-9 and Beta diversity 0.55), being copepods, molluscs, cumacea, cladocera, poliquets, decapods, mysids and amphipods the most important groups by biomass (mg/m3), finding densities up to 32.9 mg/m3 for copepods, 6 for mysids and up to 100 mg/m3 for decapods. Multivariate analysis determines depth as the most important variable explaining community structure, decreasing biodiversity with depth, while for sites at depths species show seasonal horizontal migrations between GoC and GE, connecting terrestrial and marine ecosystems.

  14. [Perissodactyla: the primary structure of hemoglobins from the lowland tapir (Tapirus terrestris): glutamic acid in position 2 of the beta chains].

    Science.gov (United States)

    Mazur, G; Braunitzer, G

    1984-09-01

    The hemoglobins from a lowland tapir (Tapirus terrestris) were analysed and the complete primary structure is described. The globin chains were separated on CM cellulose column in 8M urea and the amino-acid sequences were determined in the liquid phase sequenator. The results show that globin consists of two alpha chains (alpha I and alpha II) and beta major and beta minor components. The alpha chains differ only at one position: alpha I contains aspartic acid and alpha II glycine. The beta chains are heterogeneous: aspartic and glutamic acid were found at position beta 21 and beta 73 of the beta major components and asparagine and serine at position beta 139. In the beta minor components four positions were found with more than one amino acid, namely beta 2, beta 4, beta 6 and beta 56. The sequences are compared with those of man, horse and rhinoceros. Four residues of horse methemoglobin, which are involved in the alpha 1 beta 1 contacts are substituted in tapir hemoglobins. In the alpha chains: alpha 107(G14)Ser----Val, alpha 111-(G18) Val----Leu, alpha 115(GH3) Asn----Asp or Gly; in the beta chains: beta 116(G18) Arg----Gln. The amino acid at beta 2 of the major components is glutamic acid while glutamine and histidine are found in the minor components. Although glutamic acid, a binding site for ATP, does not interact with 2,3-bisphosphoglycerate, glutamine and histidine in the minor components are responsible for the slight effect of 2,3-bisphosphoglycerate on tapir hemoglobin.

  15. Numerical analysis of pipe impact on reinforced concrete structures

    International Nuclear Information System (INIS)

    Prinja, N.K.

    1990-01-01

    This paper presents the methodology and the results of numerical analyses carried out by using the computer code DYNA3D to analyse pipe impacts on a reinforced concrete slab, a floor beam and a column. Modelling techniques employed to represent various features of typical reinforced concrete (RC) structures and the details of a soil and crushable foam type of material model used to represent concrete material behaviour are described. The results show that a reasonable prediction of global behaviour of reinforced concrete structures under impact loading can be obtained by this numerical method. (author)

  16. Mechanical properties and impact behavior of a microcellular structural foam

    Directory of Open Access Journals (Sweden)

    M. Avalle

    Full Text Available Structural foams are a relatively new class of materials with peculiar characteristics that make them very attractive in some energy absorption applications. They are currently used for packaging to protect goods from damage during transportation in the case of accidental impacts. Structural foams, in fact, have sufficient mechanical strength even with reduced weight: the balance between the two antagonist requirements demonstrates that these materials are profitable. Structural foams are generally made of microcellular materials, obtained by polymers where voids at the microscopic level are created. Although the processing technologies and some of the material properties, including mechanical, are well known, very little is established for what concerns dynamic impact properties, for the design of energy absorbing components made of microcellular foams. The paper reports a number of experimental results, in different loading conditions and loading speed, which will be a basis for the structural modeling.

  17. Determinants of capital structure and financial crisis impact: evidence

    OpenAIRE

    Proença, Pedro Miguel Correia

    2012-01-01

    Mestrado em contabilidade The objectives of this empirical work are to investigate the determinants of Portuguese SMEs capital structure, evaluate whether and how the impacts of those determinants affect the debt ratios and examine the effects of financial crisis and industry on Portuguese SMEs capital structure. The sample used considers the period 2007-2010, resulting in 12.857 Portugues e SMEs per year observations. R...

  18. Structural analysis of aircraft impact on a nuclear powered ship

    International Nuclear Information System (INIS)

    Dietrich, R.

    1976-01-01

    As part of a general safety analysis, the reliability against structural damage due to an aircraft crash on a nuclear powered ship is evaluated. This structural analysis is an aid in safety design. It is assumed that a Phantom military jet-fighter hits a nuclear powered ship. The total reaction force due to such an aircraft impact on a rigid barrier is specified in the guidelines of the Reaktor-Sicherheitskommission (German Safety Advisory Committee) for pressurized water reactors. This paper investigates the aircraft impact on the collision barrier at the side of the ship. The aircraft impact on top of the reactor hatchway is investigated by another analysis. It appears that the most unfavorable angle of impact is always normal to the surface of the collision barrier. Consequently, only normal impact will be considered here. For the specific case of an aircraft striking a nuclear powered ship, the following two effects are considered: Local penetration and dynamic response of the structure. (Auth.)

  19. Calculation of forces arising from impacting projectiles upon yielding structures

    International Nuclear Information System (INIS)

    Drittler, K.; Gruner, P.; Krivy, J.

    1977-01-01

    Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building [QUOTE]acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might-in general-be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behaviour of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. The calculations are performed with a one-dimensional model for the projectile. The presented model calculations seem to verify that the motion of the target does not have much influence on the impact force for projectiles similar to the model projectile, provided the displacement of the yielding target is small in comparison with the path covered by the free-flying projectile during a time which is equivalent to the total time of impact. (Auth.)

  20. Nonlinear system identification of smart structures under high impact loads

    Science.gov (United States)

    Sarp Arsava, Kemal; Kim, Yeesock; El-Korchi, Tahar; Park, Hyo Seon

    2013-05-01

    The main purpose of this paper is to develop numerical models for the prediction and analysis of the highly nonlinear behavior of integrated structure control systems subjected to high impact loading. A time-delayed adaptive neuro-fuzzy inference system (TANFIS) is proposed for modeling of the complex nonlinear behavior of smart structures equipped with magnetorheological (MR) dampers under high impact forces. Experimental studies are performed to generate sets of input and output data for training and validation of the TANFIS models. The high impact load and current signals are used as the input disturbance and control signals while the displacement and acceleration responses from the structure-MR damper system are used as the output signals. The benchmark adaptive neuro-fuzzy inference system (ANFIS) is used as a baseline. Comparisons of the trained TANFIS models with experimental results demonstrate that the TANFIS modeling framework is an effective way to capture nonlinear behavior of integrated structure-MR damper systems under high impact loading. In addition, the performance of the TANFIS model is much better than that of ANFIS in both the training and the validation processes.

  1. Impact of structured education on glucose control and ...

    African Journals Online (AJOL)

    Objective: To assess the impact of structured education on glucose control and hypoglycaemia in the management of Type-2 diabetes. Methods: A systematic review was done using Medline via Ovid and EMBASE databases of published English literature between 1980 and 2014. Included studies were randomized control ...

  2. Calculation of forces arising from impacting projectiles upon yielding structures

    International Nuclear Information System (INIS)

    Drittler, K.; Gruner, P.; Krivy, J.

    1977-01-01

    Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building 'acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might -in general- be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behavior of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. In view of the applications of the calculations to the impact of airplanes upon buildings which are constructed to withstand loads of this kind without serious damage and without large deformations, it is possible to simplify the calculations to some extent. That is, the investigations need not take into account in detail the behavior of the target during impact. The calculations are performed with a one-dimensional model for the projectile. The direction of impact is perpendicular to the target surface; direction of impact and projectile axis coincide. The calculations were performed for several initial velocities of the projectiles simulating a fast flying military airplane. Variations of the peak values of the load functions as compared to corresponding values for a rigid target do not exceed about 10%. The overall temporal behavior of the load curves turns out to be not very sensitive to the yielding of the target, though, in some cases displacements in time of the peak positions within a single load curve do arise

  3. Impacts of land use and cover change on terrestrial carbon stocks and the micro-climate over urban surface: a case study in Shanghai, China

    Science.gov (United States)

    Zhang, F.; Zhan, J.; Bai, Y.

    2016-12-01

    Land use and cover change is the key factor affecting terrestrial carbon stocks and micro-climate, and their dynamics not only in regional ecosystems but also in urbanized areas. Using the typical fast-growing city of Shanghai, China as a case study, this paper explored the relationships between terrestrial carbon stocks, micro-climate and land cover within an urbanized area. The main objectives were to assess variation in soil carbon stocks and local climate conditions across terrestrial land covers with different intensities of urban development, and quantify spatial distribution and dynamic variation of carbon stocks and microclimate in response to urban land use and cover change. On the basis of accurate spatial datasets derived from a series of Landsat TM images during the years 1988 to 2010 and reliable estimates of urban climate and soil carbon stocks using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, our results showed that carbon stocks per unit area in terrestrial land covers decreased and urban temperature increased with increasing intensity of urban development. Urban land use and cover change and sealing of the soil surface created hotspots for losses in carbon stocks. Total carbon stocks in Shanghai decreased by about 30%-35%, representing a 1.5% average annual decrease, and the temperature increased by about 0.23-0.4°/10a during the past 20 years. We suggested potential policy measures to mitigate negative effects of land use and cover change on carbon stocks and microclimate in urbanized areas.

  4. Behaviour of cellular structures with fluid fillers under impact loading

    Directory of Open Access Journals (Sweden)

    Matej Vesenjak

    2007-03-01

    Full Text Available The paper investigates the behaviour of closed- and open-cell cellular structures under uniaxial impact loading by means of computational simulations using the explicit nonlinear finite element code LS-DYNA. Simulations also consider the influence of pore fillers and the base material strain rate sensitivity. The behaviour of closed-cell cellular structure has been evaluated with use of the representative volume element, where the influence of residual gas inside the closed pores has been studied. Open- cell cellular structure was modelled as a whole to properly account for considered fluid flow through the cells, which significantly influences macroscopic behaviour of the cellular structure. The fluid has been modelled by applying a meshless Smoothed Particle Hydrodynamics (SPH method. Parametric computational simulations provide grounds for optimization of cellular structures to satisfy different requirements, which makes them very attractive for use in general engineering applications.

  5. Adequacy of Pay Structure and Its Impact on Personal Outcomes

    Directory of Open Access Journals (Sweden)

    Siti Salwa Salim

    2015-12-01

    Full Text Available Pay structure consists of two salient elements: monetary and non-monetary rewards. The ability of administrators to adequately provide these rewards may have a significant impact on personal outcomes. Although this relationship is vital, the role of adequacy of pay structures as an important antecedent was given less emphasis in the organizational pay structure research literature. Thus, this study was undertaken to examine the association between the adequacy of pay structure and personal outcomes. A survey method was conducted to collect data from employees who worked in private institutions of higher learning in Malaysia. The SmartPLS path model analysis demonstrated that job satisfaction and organizational commitment were important outcomes of the adequacy of pay structure in the studied organizations. Furthermore, this study also provided the relevant discussions, implications and conclusion.

  6. Impact of Financial Structure on the Cost of Solar Energy

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsohn, M.; Kreycik, C.; Bird, L.; Schwabe, P.; Cory, K.

    2012-03-01

    To stimulate investment in renewable energy generation projects, the federal government developed a series of support structures that reduce taxes for eligible investors--the investment tax credit, the production tax credit, and accelerated depreciation. The nature of these tax incentives often requires an outside investor and a complex financial arrangement to allocate risk and reward among the parties. These financial arrangements are generally categorized as 'advanced financial structures.' Among renewable energy technologies, advanced financial structures were first widely deployed by the wind industry and are now being explored by the solar industry to support significant scale-up in project development. This report describes four of the most prevalent financial structures used by the renewable sector and evaluates the impact of financial structure on energy costs for utility-scale solar projects that use photovoltaic and concentrating solar power technologies.

  7. Introduced Terrestrial Species (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted future potential distributions of terrestrial plants, animals, and pathogens non-native to the Middle-Atlantic region. These data are...

  8. Terrestrial ecosystems and biodiversity

    CSIR Research Space (South Africa)

    Davis-Reddy, Claire

    2017-10-01

    Full Text Available Ecoregions Terrestrial Biomes Protected Areas Climate Risk and Vulnerability: A Handbook for Southern Africa | 75 7.2. Non-climatic drivers of ecosystem change 7.2.1. Land-use change, habitat loss and fragmentation Land-use change and landscape... concentrations of endemic plant and animal species, but these mainly occur in areas that are most threatened by human activity. Diverse terrestrial ecosystems in the region include tropical and sub-tropical forests, deserts, savannas, grasslands, mangroves...

  9. Impact of small-scale structures on estuarine circulation

    Science.gov (United States)

    Liu, Zhuo; Zhang, Yinglong J.; Wang, Harry V.; Huang, Hai; Wang, Zhengui; Ye, Fei; Sisson, Mac

    2018-05-01

    We present a novel and challenging application of a 3D estuary-shelf model to the study of the collective impact of many small-scale structures (bridge pilings of 1 m × 2 m in size) on larger-scale circulation in a tributary (James River) of Chesapeake Bay. We first demonstrate that the model is capable of effectively transitioning grid resolution from 400 m down to 1 m near the pilings without introducing undue numerical artifact. We then show that despite their small sizes and collectively small area as compared to the total channel cross-sectional area, the pilings exert a noticeable impact on the large-scale circulation, and also create a rich structure of vortices and wakes around the pilings. As a result, the water quality and local sedimentation patterns near the bridge piling area are likely to be affected as well. However, when evaluating over the entire waterbody of the project area, the near field effects are weighed with the areal percentage which is small compared to that for the larger unaffected area, and therefore the impact on the lower James River as a whole becomes relatively insignificant. The study highlights the importance of the use of high resolution in assessing the near-field impact of structures.

  10. Magnetic Properties of Three Impact Structures in Canada

    Science.gov (United States)

    Scott, R. G.; Pilkington, M.; Tanczyk, E. I.; Grieve, R. A. F.

    1995-09-01

    Magnetic anomaly lows associated with the West Hawk Lake (Manitoba), Deep Bay (Saskatchewan) and Clearwater Lakes (Quebec) impact structures, are variable in lateral extent and intensity, a characteristic shared with most impact structures [1]. Drill core from the centres of these structures provides a unique opportunity to ground truth the causes of the reduction in magnetic field intensity in impact structures. Magnetic susceptibility and remanent magnetization levels have been found to be well below regional levels in melt rocks, impact breccias, fractured/shocked basement rocks in the central uplifts, and post-impact sediments. Deep Bay, formed in Pre-Cambrian paragneisses, is a complex crater with a submerged central uplift. It has been extensively infilled with non-magnetic black shales of Cretaceous age [2]. An airborne magnetic low of about 100 nT is associated with the Deep Bay structure. Below the shales and along the rim of the structure are highly brecciated country rocks with variable amounts of very fine rock flour. Susceptibility and remanent magnetization are both weak due to extensive alteration in the brecciated rocks. Alteration of the brecciated rocks, and the effect of several hundred meters of non-magnetic sedimentary infill, both contribute to the magnetic low. West Hawk Lake, a simple crater, was excavated in metavolcanic and metasedimentary rocks of the Superior Province [3], and has a ground magnetic low of about 250 nT. As with Deep Bay, West Hawk Lake has been infilled with dominantly non-magnetic sediments. Brecciation and alteration are extensive, with breccia derived from greenschist-facies meta-andesite displaying slightly higher susceptibilities and remanent magnetizations than breccia derived from the more felsic metasediments. Brecciation has effectively randomized magnetization vectors, and subsequent alteration resulted in the destruction of magnetic phases. These two factors contribute to the magnetic low over this structure

  11. Analysis of Dynamic Properties of Piezoelectric Structure under Impact Load

    Directory of Open Access Journals (Sweden)

    Taotao Zhang

    2015-10-01

    Full Text Available An analytical model of the dynamic properties is established for a piezoelectric structure under impact load, without considering noise and perturbations in this paper. Based on the general theory of piezo-elasticity and impact mechanics, the theoretical solutions of the mechanical and electrical fields of the smart structure are obtained with the standing and traveling wave methods, respectively. The comparisons between the two methods have shown that the standing wave method is better for studying long-time response after an impact load. In addition, good agreements are found between the theoretical and the numerical results. To simulate the impact load, both triangle and step pulse loads are used and comparisons are given. Furthermore, the influence of several parameters is discussed so as to provide some advices for practical use. It can be seen that the proposed analytical model would benefit, to some extent, the design and application (especially the airport runway of the related smart devices by taking into account their impact load performance.

  12. Impact induced solitary wave propagation through a woodpile structure

    International Nuclear Information System (INIS)

    Kore, R; Waychal, A; Yadav, P; Shelke, A; Agarwal, S; Sahoo, N; Uddin, Ahsan

    2016-01-01

    In this paper, we investigate solitary wave propagation through a one-dimensional woodpile structure excited by low and high velocity impact. Woodpile structures are a sub-class of granular metamaterial, which supports propagation of nonlinear waves. Hertz contact law governs the behavior of the solitary wave propagation through the granular media. Towards an experimental study, a woodpile structure was fabricated by orthogonally stacking cylindrical rods. A shock tube facility has been developed to launch an impactor on the woodpile structure at a velocity of 30 m s −1 . Embedded granular chain sensors were fabricated to study the behavior of the solitary wave. The impact induced stress wave is studied to investigate solitary wave parameters, i.e. contact force, contact time, and solitary wave velocity. With the aid of the experimental setup, numerical simulations, and a theoretical solution based on the long wavelength approximation, formation of the solitary wave in the woodpile structure is validated to a reasonable degree of accuracy. The nondispersive and compact supported solitary waves traveling at sonic wave velocity offer unique properties that could be leveraged for application in nondestructive testing and structural health monitoring. (paper)

  13. Structural analysis of aircraft impact on a nuclear powered ship

    International Nuclear Information System (INIS)

    Dietrich, R.

    1976-01-01

    The paper investigates the aircraft impact on the collision barrier at the side of the ship. The aircraft impact on top of the reactor hatchway is investigated by another analysis. It appears that the most unfavorable angle of impact is always normal to the surface of the collision barrier. Consequently, only normal impact will be considered here. For the specific case of an aircraft striking a nuclear powered ship, the following two effects are considered: Local penetration and dynamic response of the structuure. The local penetration occurs at points where the engines or other rigid objects hit the structure. It is assumed that the aircraft engine is a rigid body projectile and the side wall of the ship is the target. The applied steel penetration formulae for projectiles were empirically derived for military applications, where both the projectile and the target are unlike those of an impact of an aircraft engine. For this reason it is expedient to calculate the upper and the lower limit values of the penetration depths. The results show that the highest penetration depth is less than the sum of all wall thicknesses of the collision barrier. The solution of the dynamic analysis is obtained by using the finite element method. The results are the eigenmodes, the eigenfrequencies, the displacements of the nodes, and the stresses in the applied plane stress elements. It is shown that the maximum stress which only appears in one element is on the same level as the yield stress of the St. 42 steel. The structural analysis shows that the collision barrier is a sufficient safeguard against the perforation of the engine and against the cracking of the structure as a result of the dynamic response to an aircraft impact. (orig./HP) [de

  14. Meteorite impact craters and possibly impact-related structures in Estonia

    Science.gov (United States)

    Plado, Jüri

    2012-10-01

    Three structures (Neugrund, Kärdla, and Kaali) of proven impact origin make Estonia the most cratered country in the world by area. In addition, several candidate impact structures exist, waiting for future studies to determine their origin. This article is an overview of these proven and possible impact structures, including some breccia layers. It summarizes the information and descriptions of the morphology; geological characteristics; and mineralogical, chemical, and geophysical data available in the literature. The overview was prepared to make information in many earlier publications in local journals (many of which had been published in Estonian or Russian) accessible to the international community. This review summarizes the facts and observations in a historical fashion, summarizing the current state of knowledge with some additional comments, and providing the references.

  15. Sensitivity of nuclear power plant structural response to aircraft impact

    International Nuclear Information System (INIS)

    Buchhardt, F.; Magiera, G.; Matthees, W.; Weber, M.

    1984-01-01

    In this paper a sensitivity study for aircraft impact is performed concerning the excitation of internal components, with particular regard to nonlinear structural material behaviour in the impact area. The nonlinear material values are varied within the bandwidth of suitable material strength, depending on local stiffness pre-calculations. The analyses are then performed on a globally discretized three-dimensional finite element model of a nuclear power plant, using a relatively fine mesh. For specified nodal points results are evaluated by comparing their response spectra. (Author) [pt

  16. The design of impact absorbing structures for additive manufacture

    International Nuclear Information System (INIS)

    Brennan-Craddock, J; Brackett, D; Wildman, R; Hague, R

    2012-01-01

    Additive manufacturing (AM) is increasingly becoming a viable manufacturing process due to dramatic advantages that it facilitates in the area of design complexity. This paper investigates the potential of additively manufactured lattice structures for the application of tailored impact absorption specifically for conformal body protection. It explores lattice cell types based on foam microstructures and assesses their suitability for impact absorption. The effect of varying the cell strut edge design is also investigated. The implications of scaling these cells up for AM are discussed as well as the design issues regarding the handling of geometric complexity and the requirement for body conformity. The suitability of AM materials for this application is also discussed.

  17. 3D-finite element impact simulation on concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Heider, N.

    1989-12-15

    The analysis of impact processes is an interesting application of full 3D Finite Element calculations. This work presents a simulation of the penetration process of a Kinetic Energy projectile into a concrete target. Such a calculation requires an adequate FE model, especially a proper description of the crack opening process in front of the projectile. The aim is the prediction of the structural survival of the penetrator case with the help of an appropriate failure criterion. Also, the computer simulation allows a detailed analysis of the physical phenomena during impact. (orig.) With 4 refs., 14 figs.

  18. Variations of the Electron Fluxes in the Terrestrial Radiation Belts Due To the Impact of Corotating Interaction Regions and Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Benacquista, R.; Boscher, D.; Rochel, S.; Maget, V.

    2018-02-01

    In this paper, we study the variations of the radiation belts electron fluxes induced by the interaction of two types of solar wind structures with the Earth magnetosphere: the corotating interaction regions and the interplanetary coronal mass ejections. We use a statistical method based on the comparison of the preevent and postevent fluxes. Applied to the National Oceanic and Atmospheric Administration-Polar Operational Environmental Satellites data, this gives us the opportunity to extend previous studies focused on relativistic electrons at geosynchronous orbit. We enlighten how corotating interaction regions and Interplanetary Coronal Mass Ejections can impact differently the electron belts depending on the energy and the L shell. In addition, we provide a new insight concerning these variations by considering their amplitude. Finally, we show strong relations between the intensity of the magnetic storms related to the events and the variation of the flux. These relations concern both the capacity of the events to increase the flux and the deepness of these increases.

  19. Grid faults' impact on wind turbine structural loads

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Iov, F.

    2007-01-01

    The objective of this work is to illustrate the impact of the grid faults on the wind turbine structural loads. Grid faults are typically simulated in detailed power system simulation tools, which by applying simplified mechanical models, are not able to provide a throughout insight...... on the structural loads caused by sudden disturbances on the grid. On the other hand, structural loads of the wind turbine are typically assessed in advanced aerolastic computer codes, which by applying simplified electrical models do not provide detailed electrical insight. This paper presents a simulation...... strategy, where the focus is on how to access a proper combination of two complimentary simulations tools, such as the advanced aeroelastic computer code HAWC2 and the detailed power system simulation tool DIgSILENT, in order to provide a whole overview of both the structural and the electrical behaviour...

  20. Strategic Planning Process and Organizational Structure: Impacts, Confluence and Similarities

    Directory of Open Access Journals (Sweden)

    Dyogo Felype Neis

    2017-01-01

    Full Text Available This article aims to analyze the relationship between the strategic planning process and organizational structure in the reality of a complex organization: the Public Prosecutor’s Office of Santa Catarina (MPSC. The research is set by the single case study research strategy and data were collected through the following instruments: bibliographical research, documentary research, semi-structured interviews and systematic observation. The conclusion indicates that the phases of the strategic planning process influence and are influenced by the elements of the organizational structure and highlights the confluences, the impacts and similarities between the stages of formulation and implementation of the strategic process with the various constituent elements of the organizational structure.

  1. Behavior of auxetic structures under compression and impact forces

    Science.gov (United States)

    Yang, Chulho; Vora, Hitesh D.; Chang, Young

    2018-02-01

    In recent years, various auxetic material structures have been designed and fabricated for diverse applications that utilize normal materials that follow Hooke’s law but still show the properties of negative Poisson’s ratios (NPR). One potential application is body protection pads that are comfortable to wear and effective in protecting body parts by reducing impact force and preventing injuries in high-risk individuals such as elderly people, industrial workers, law enforcement and military personnel, and athletes. This paper reports an integrated theoretical, computational, and experimental investigation conducted for typical auxetic materials that exhibit NPR properties. Parametric 3D CAD models of auxetic structures such as re-entrant hexagonal cells and arrowheads were developed. Then, key structural characteristics of protection pads were evaluated through static analyses of FEA models. Finally, impact analyses were conducted through dynamic simulations of FEA models to validate the results obtained from the static analyses. Efforts were also made to relate the individual and/or combined effect of auxetic structures and materials to the overall stiffness and shock-absorption performance of the protection pads. An advanced additive manufacturing (3D printing) technique was used to build prototypes of the auxetic structures. Three different materials typically used for fused deposition modeling technology, namely polylactic acid (PLA) and thermoplastic polyurethane material (NinjaFlex® and SemiFlex®), were used for different stiffness and shock-absorption properties. The 3D printed prototypes were then tested and the results were compared to the computational predictions. The results showed that the auxetic material could be effective in reducing the shock forces. Each structure and material combination demonstrated unique structural properties such as stiffness, Poisson’s ratio, and efficiency in shock absorption. Auxetic structures showed better shock

  2. A Possible Buried Impact Structure Near Bow City, Alberta

    Science.gov (United States)

    Xie, W.; Glombick, P.; Schmitt, D. R.; Bown, T. D.

    2012-12-01

    In recent years, improved exploration techniques have resulted in the serendipitous discoveries of increasing numbers of extraterrestrial impact structures in sedimentary basins around the world. Following in this tradition, a new potential impact structure centered near 50.4°N, 112.35°N in SE Alberta has been identified. The first indications of this structure appeared in careful systematic mapping of Cretaceous age sediments using public domain well log information that showed overturned and missing components in what regionally is a simple layered stratigraphy. This motivated the examination of legacy 2D seismic profiles over the area that confirmed the stratigraphic anomalies and provided new details that further supported interpretation of a potential impact structure. Further, the existence of unexpected faults through the Cretaceous Bearpaw formation had been noted as early as the 1940's in the limited outcrop available in coulees, and these as well as other complex fault structures along the Bow River outcrops were confirmed in recent field visits to the site. The 2D seismic data displays a number of listric and rose-petal faulting consistent with late stage collapse of the impact crater. Further, a seismically transparent central uplift peak is visible. Based on the results, the structure is recognized as a complex crater with a diameter of approximately 8 kilometers and, today, bottoming at a depth of 900 meters from the current surface. Currently, the age of the feature is grossly estimated to be less than 70 my on the basis of underlying undisturbed seismic reflectors. The structure may be somewhat unique in that weak coals surrounding the feature are clearly thickened indicating outward lateral sliding along shear planes through weaker layers. Work in progress includes acquisition of a high resolution seismic profile and detailed mapping of the magnetic and gravity potential fields. More detailed mapping will include searches for shock metamorphism

  3. Parallel Computing for Terrestrial Ecosystem Carbon Modeling

    International Nuclear Information System (INIS)

    Wang, Dali; Post, Wilfred M.; Ricciuto, Daniel M.; Berry, Michael

    2011-01-01

    Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO 2 . The influence of terrestrial ecosystems on atmospheric CO 2 can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO 2 concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO 2 uptake and respiratory CO 2 release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change

  4. Impact testing and analysis for structural code benchmarking

    International Nuclear Information System (INIS)

    Glass, R.E.

    1989-01-01

    Sandia National Laboratories, in cooperation with industry and other national laboratories, has been benchmarking computer codes (''Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Cask,'' R.E. Glass, Sandia National Laboratories, 1985; ''Sample Problem Manual for Benchmarking of Cask Analysis Codes,'' R.E. Glass, Sandia National Laboratories, 1988; ''Standard Thermal Problem Set for the Evaluation of Heat Transfer Codes Used in the Assessment of Transportation Packages, R.E. Glass, et al., Sandia National Laboratories, 1988) used to predict the structural, thermal, criticality, and shielding behavior of radioactive materials packages. The first step in the benchmarking of the codes was to develop standard problem sets and to compare the results from several codes and users. This step for structural analysis codes has been completed as described in ''Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Casks,'' R.E. Glass, Sandia National Laboratories, 1985. The problem set is shown in Fig. 1. This problem set exercised the ability of the codes to predict the response to end (axisymmetric) and side (plane strain) impacts with both elastic and elastic/plastic materials. The results from these problems showed that there is good agreement in predicting elastic response. Significant differences occurred in predicting strains for the elastic/plastic models. An example of the variation in predicting plastic behavior is given, which shows the hoop strain as a function of time at the impacting end of Model B. These differences in predicting plastic strains demonstrated a need for benchmark data for a cask-like problem. 6 refs., 5 figs

  5. The ecology of seamounts: structure, function, and human impacts.

    OpenAIRE

    Clark, MR; Rowden, AA; Schlacher, T; Williams, A; Consalvey, M; Stocks, KI; Rogers, AD; O'Hara, TD; White, M; Shank, TM; Hall-Spencer, JM

    2010-01-01

    In this review of seamount ecology, we address a number of key scientific issues concerning the structure and function of benthic communities, human impacts, and seamount management and conservation. We consider whether community composition and diversity differ between seamounts and continental slopes, how important dispersal capabilities are in seamount connectivity, what environmental factors drive species composition and diversity, whether seamounts are centers of enhanced biological prod...

  6. Nonlinear system identification of smart structures under high impact loads

    International Nuclear Information System (INIS)

    Sarp Arsava, Kemal; Kim, Yeesock; El-Korchi, Tahar; Park, Hyo Seon

    2013-01-01

    The main purpose of this paper is to develop numerical models for the prediction and analysis of the highly nonlinear behavior of integrated structure control systems subjected to high impact loading. A time-delayed adaptive neuro-fuzzy inference system (TANFIS) is proposed for modeling of the complex nonlinear behavior of smart structures equipped with magnetorheological (MR) dampers under high impact forces. Experimental studies are performed to generate sets of input and output data for training and validation of the TANFIS models. The high impact load and current signals are used as the input disturbance and control signals while the displacement and acceleration responses from the structure–MR damper system are used as the output signals. The benchmark adaptive neuro-fuzzy inference system (ANFIS) is used as a baseline. Comparisons of the trained TANFIS models with experimental results demonstrate that the TANFIS modeling framework is an effective way to capture nonlinear behavior of integrated structure–MR damper systems under high impact loading. In addition, the performance of the TANFIS model is much better than that of ANFIS in both the training and the validation processes. (paper)

  7. Impact testing and analysis for structural code benchmarking

    International Nuclear Information System (INIS)

    Glass, R.E.

    1989-01-01

    Sandia National Laboratories, in cooperation with industry and other national laboratories, has been benchmarking computer codes used to predict the structural, thermal, criticality, and shielding behavior of radioactive materials packages. The first step in the benchmarking of the codes was to develop standard problem sets and to compare the results from several codes and users. This step for structural analysis codes has been completed as described in Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Casks, R.E. Glass, Sandia National Laboratories, 1985. The problem set is shown in Fig. 1. This problem set exercised the ability of the codes to predict the response to end (axisymmetric) and side (plane strain) impacts with both elastic and elastic/plastic materials. The results from these problems showed that there is good agreement in predicting elastic response. Significant differences occurred in predicting strains for the elastic/plastic models. An example of the variation in predicting plastic behavior is given, which shows the hoop strain as a function of time at the impacting end of Model B. These differences in predicting plastic strains demonstrated a need for benchmark data for a cask-like problem

  8. Rare earth impact on glass structure and alteration kinetics

    International Nuclear Information System (INIS)

    Molieres, E.

    2012-01-01

    This work is related to the question of the geological deep repository of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated. (author) [fr

  9. Impact analysis of automotive structures with distributed smart material systems

    Science.gov (United States)

    Peelamedu, Saravanan M.; Naganathan, Ganapathy; Buckley, Stephen J.

    1999-06-01

    New class of automobiles has structural skins that are quite different from their current designs. Particularly, new families of composite skins are developed with new injection molding processes. These skins while support the concept of lighter vehicles of the future, are also susceptible to damage upon impact. It is important that their design should be based on a better understanding on the type of impact loads and the resulting strains and damage. It is possible that these skins can be integrally designed with active materials to counter damages. This paper presents a preliminary analysis of a new class of automotive skins, using piezoceramic as a smart material. The main objective is to consider the complex system with, the skin to be modeled as a layered plate structure involving a lightweight material with foam and active materials imbedded on them. To begin with a cantilever beam structure is subjected to a load through piezoceramic and the resulting strain at the active material site is predicted accounting for the material properties, piezoceramic thickness, adhesive thickness including the effect of adhesives. A finite element analysis is carried out to compare experimental work. Further work in this direction would provide an analytical tool that will provide the basis for algorithms to predict and counter impacts on the future class of automobiles.

  10. Terrestrial Analogs to Mars

    Science.gov (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

    2002-08-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  11. Linking animals aloft with the terrestrial landscape

    Science.gov (United States)

    Buler, Jeffrey J.; Barrow, Wylie; Boone, Matthew; Dawson, Deanna K.; Diehl, Robert H.; Moore, Frank R.; Randall, Lori A.; Schreckengost, Timothy; Smolinsky, Jaclyn A.

    2018-01-01

    Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. We highlight a recently developed methodological approach that precisely and quantitatively links the horizontal spatial structure of birds aloft to their terrestrial distributions and provides novel insights into avian ecology and conservation across broad landscapes. Specifically, we present case studies that (1) elucidate how migrating birds contend with crossing ecological barriers and extreme weather events, (2) identify important stopover areas and habitat use patterns of birds along their migration routes, and (3) assess waterfowl response to wetland habitat management and restoration. These studies aid our understanding of how anthropogenic modification of the terrestrial landscape (e.g., urbanization, habitat management), natural geographic features, and weather (e.g., hurricanes) can affect the terrestrial distributions of flying animals.

  12. Impact of tillage intensity on clay loam soil structure

    DEFF Research Database (Denmark)

    Daraghmeh, Omar; Petersen, Carsten; Munkholm, Lars Juhl

    Soil structure and structural stability are key parameters in sustainable soil management and optimum cropping practices. Locally and temporally adapted precision tillage may improve crop performance while at the same time reduce environmental impacts. The main objective of this study...... was to improve the knowledge of precision tillage practices through characterizing the effect of varied tillage intensities on structural properties of a clay loam soil. A field experiment was conducted using a randomized complete block design with two main factors, i.e. operational speed (OS, 2 levels......) and rotovating speed (RS, 3 levels). The tillage was conducted using a PTO-driven rotovator equipped to measure angular velocity. The effect of traffic compaction, made directly after tillage, was measured on soil taken from wheel track (WT) compared with soil outside wheel track (NWT). Soil samples from 0-3 cm...

  13. Vegetation Structure, Tree Volume and Biomass Estimation using Terrestrial Laser Scanning Remote Sensing: A Case Study of the Mangrove Forests in the Everglades National Park

    Science.gov (United States)

    Feliciano, E. A.; Wdowinski, S.; Potts, M. D.

    2012-12-01

    Mangrove forests are being threatened by accelerated climate change, sea level rise and coastal projects. Carbon/above ground biomass (AGB) losses due to natural or human intervention can affect global warming. Thus, it is important to monitor AGB fluctuations in mangrove forests similar to those inhabiting the Everglades National Park (ENP). Tree volume and tree wood specific density are two important measurements for the estimation of AGB (mass = volume * density). Wood specific density is acquired in the laboratory by analyzing stem cores acquired in the field. However, tree volume is a challenging task because trees resemble tapered surfaces. The majority of published studies estimate tree volume and biomass using allometric equations, which describe the size, shape, volume or AGB of a given population of trees. However, these equations can be extremely general and might not give a representative value of volume or AGB for a specific tree species. In order to have precise biomass estimations, other methodologies for tree volume estimation are needed. To overcome this problem, we use a state-of-the-art remote sensing tool known as ground-based LiDAR a.k.a Terrestrial Laser Scanner (TLS), which can be used to precisely measure vegetation structure and tree volume from its 3-D point cloud. We surveyed three mangrove communities: (Rhizophora mangle, Laguncuria racemosa and Avicennia germinans) in three different sites along Shark River Slough (SRS), which is the primary source of water to the ENP. Our sites included: small-, intermediate- and tall- size mangroves. Our ground measurements included both: traditional forestry surveys and TLS surveys for tree attributes (tree height and diameter at breast height (DBH)) comparison. These attributes are used as input to allometric equations for the estimation of tree volume and AGB. A total of 25 scans were collected in 2011 with a Leica ScanStation C10 TLS. The 3-D point cloud acquired from the TLS data revealed that

  14. Hailar crater - A possible impact structure in Inner Mongolia, China

    Science.gov (United States)

    Xiao, Zhiyong; Chen, Zhaoxu; Pu, Jiang; Xiao, Xiao; Wang, Yichen; Huang, Jun

    2018-04-01

    Hailar crater, a probable impact structure, is a circular depression about 300 m diameter in Inner Mongolia, northeast China. With broad elevated rims, the present rim-to-floor depth is 8-20 m. Regional geological background and geomorphological comparison suggest that this feature is likely not formed by surface processes such as salt diapir, karst, aeolian, glacial, or volcanic activity. Its unique occurrence in this region and well-preserved morphology are most consistent with it being a Cenozoic impact crater. Two field expeditions in 2016 and 2017 investigated the origin of this structure, recognizing that (1) no additional craters were identified around Hailar crater in the centimeter-scale digital topography models that were constructed using a drone imaging system and stereo photogrammetry; (2) no bedrock exposures are visible within or adjacent to the crater because of thick regolith coverage, and only small pieces of angular unconsolidated rocks are present on the crater wall and the gently-sloped crater rim, suggesting recent energetic formation of the crater; (3) most samples collected from the crater have identical lithology and petrographic characteristics with the background terrain, but some crater samples contain more abundant clasts and silicate hydrothermal veins, indicating that rocks from depths have been exposed by the crater; (4) no shock metamorphic features were found in the samples after thin section examinations; and (5) a systematic sample survey and iron detector scan within and outside of the crater found no iron-rich meteorites larger than 2 cm in size in a depth of 30 cm. Although no conclusive evidence for an impact origin is found yet, Hailar crater was most likely formed by an impact based on its unique occurrence and comparative geomorphologic study. We suggest that drilling in the crater center is required to verify the impact origin, where hypothesized melt-bearing impactites may be encountered.

  15. Ethnopharmacological Studies of Tribulus Terrestris (Linn). in ...

    African Journals Online (AJOL)

    Synergism and antagonism impact of different plant metabolites present in crude fruit extract of Tribulus terrestris 'the herbal Viagra' have been studied. Variability in plant composition, biomass and metabolites concentration in different modules was significantly contributed by spatial factor. However the edhaphic ...

  16. Terrestrial and extraterrestrial fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Heymann, D.; Jenneskens, L.W.; Jehlicka, J; Koper, C.; Vlietstra, E. [Rice Univ, Houston, TX (United States). Dept. of Earth Science

    2003-07-01

    This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous-Tertiary-Boundary and Pennian-Triassic-Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated processes of fullerene formation, including the suggestion that some natural fullerenes might have formed from biological (algal) remains.

  17. Analysis of reinforced concrete structures subjected to aircraft impact loading

    International Nuclear Information System (INIS)

    Bauer, J.; Scharpf, F.; Schwarz, R.

    1983-01-01

    Concerning the evaluation of the effects of aircraft impact loading on the reactor building and the contained equipment special interest belongs to both the characteristic of loading conditions and the consideration of the nonlinear behaviour of the local impacted area as well as the overall behaviour of the structure. To cover this extensive scope of problems the fully 3-dimensional code DYSMAS/L was prepared for the analysis of highly dynamic continuum mechanics problems. For this totally Lagrangian description, derived and tested in the field of the simulation of impact phenomena and penetration of armoured structures, an extension was made for the reasonable modelling of the material behaviour of reinforced concrete. Conforming the available experimental data a nonlinear stress-strain curve is given and a continuous triaxial failure-surface is composed which allows cracking of concrete in the tensile region and its crushing in the compressive mode. For the separately modeled reinforcement an elastic-plastic stress-strain relationship with kinematic hardening is used. (orig./RW)

  18. Comparing marine and terrestrial ecosystems: Implications for the design of coastal marine reserves

    Science.gov (United States)

    Carr, M.H.; Neigel, J.E.; Estes, J.A.; Andelman, S.; Warner, R.R.; Largier, J. L.

    2003-01-01

    Concepts and theory for the design and application of terrestrial reserves is based on our understanding of environmental, ecological, and evolutionary processes responsible for biological diversity and sustainability of terrestrial ecosystems and how humans have influenced these processes. How well this terrestrial-based theory can be applied toward the design and application of reserves in the coastal marine environment depends, in part, on the degree of similarity between these systems. Several marked differences in ecological and evolutionary processes exist between marine and terrestrial ecosystems as ramifications of fundamental differences in their physical environments (i.e., the relative prevalence of air and water) and contemporary patterns of human impacts. Most notably, the great extent and rate of dispersal of nutrients, materials, holoplanktonic organisms, and reproductive propagules of benthic organisms expand scales of connectivity among near-shore communities and ecosystems. Consequently, the "openness" of marine populations, communities, and ecosystems probably has marked influences on their spatial, genetic, and trophic structures and dynamics in ways experienced by only some terrestrial species. Such differences appear to be particularly significant for the kinds of organisms most exploited and targeted for protection in coastal marine ecosystems (fishes and macroinvertebrates). These and other differences imply some unique design criteria and application of reserves in the marine environment. In explaining the implications of these differences for marine reserve design and application, we identify many of the environmental and ecological processes and design criteria necessary for consideration in the development of the analytical approaches developed elsewhere in this Special Issue.

  19. Optimum structure of Whipple shield against hypervelocity impact

    International Nuclear Information System (INIS)

    Lee, M

    2014-01-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  20. Optimum structure of Whipple shield against hypervelocity impact

    Science.gov (United States)

    Lee, M.

    2014-05-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  1. Impact of constrained rewiring on network structure and node dynamics

    Science.gov (United States)

    Rattana, P.; Berthouze, L.; Kiss, I. Z.

    2014-11-01

    In this paper, we study an adaptive spatial network. We consider a susceptible-infected-susceptible (SIS) epidemic on the network, with a link or contact rewiring process constrained by spatial proximity. In particular, we assume that susceptible nodes break links with infected nodes independently of distance and reconnect at random to susceptible nodes available within a given radius. By systematically manipulating this radius we investigate the impact of rewiring on the structure of the network and characteristics of the epidemic. We adopt a step-by-step approach whereby we first study the impact of rewiring on the network structure in the absence of an epidemic, then with nodes assigned a disease status but without disease dynamics, and finally running network and epidemic dynamics simultaneously. In the case of no labeling and no epidemic dynamics, we provide both analytic and semianalytic formulas for the value of clustering achieved in the network. Our results also show that the rewiring radius and the network's initial structure have a pronounced effect on the endemic equilibrium, with increasingly large rewiring radiuses yielding smaller disease prevalence.

  2. The Rise of the Anthroposphere since 50,000 Years: An Ecological Replacement of Megaherbivores by Humans in Terrestrial Ecosystems?

    Directory of Open Access Journals (Sweden)

    Hervé Bocherens

    2018-01-01

    Full Text Available Megaherbivores fulfilled a number of important ecological functions in terrestrial ecosystems and behaved as ecological engineers since 300 million years until around 12,000 years ago. These essential ecological functions include opening vegetation cover, selective seed dispersal and nutrient recycling and spreading. Thanks to these effects, megaherbivores change the vegetation structure where they live, with cascading effects on smaller herbivores and also on climate. The late Pleistocene extinction strongly impacted the megaherbivores almost all over the world and led to the loss of these important ecological functions in terrestrial ecosystems. These functions were partially restored by agriculturist humans through an ecological replacement that occurred through an ecological shift within the species Homo sapiens. A better understanding of the differences and similarities between the ecological impacts of megaherbivores and those of agricultural humans should help to predict the future of terrestrial ecosystems.

  3. Grid faults' impact on wind turbine structural loads

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Cutululis, N.A.; Soerensen, P.; Larsen, T.J. [Risoe National Lab., DTU, Wind Energy Dept. (Denmark); Iov, F.

    2007-11-15

    The objective of this work is to illustrate the impact of the grid faults on the wind turbine structural loads. Grid faults are typically in detailed power system simulation tools, which by applying simplified mechanical models, are not able to provide a throughout insight on the structural loads caused by sudden disturbances on the grid. On the other hand, structural loads of the wind turbine are typically assessed in advanced aeroelastic computer codes, which by applying simplified electrical models do not provide detailed electrical insight. This paper presents a simulation strategy, where the focus is on how to access a proper combination of two complementary simulation tools, such as the advanced aeroelastic computer code HAWC2 and the detailed power system simulation tool DIgSILENT, in order to provide a whole overview of both the structural and the electrical behaviour of the wind turbine during grid faults. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator. (au)

  4. Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

    Science.gov (United States)

    Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

    2016-01-01

    Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors. © 2015 John Wiley & Sons Ltd.

  5. Modeled Impacts of Farming Practices and Structural Agricultural Changes on Nitrogen Fluxes in the Netherlands

    Directory of Open Access Journals (Sweden)

    Wim de Vries

    2001-01-01

    Full Text Available In the Netherlands, nutrient emissions from intensive animal husbandry have contributed to decreased species diversity in (semi natural terrestrial and aquatic ecosystems, pollution of groundwater, and possibly global warming due to N2O emissions. This paper presents the results of a modelling study presenting the impacts of both structural measures and improved farming practices on major nitrogen (N fluxes, including NH3 and N2O emission, uptake, leaching, and runoff, in the Netherlands, using input data for the year 2000. Average annual fluxes (Gg N year–1 for the year 2000 were estimated at 132 for NH3 emission (160 Gg NH3 year–1, 28 for N2O emission, 50 for N inflow to groundwater, and 15 for N inflow to surface water at a total N input of 1046. At this input, nitrate (NO3 concentrations in groundwater often exceeded the target of 50 mg NO3 l–1, specifically in well-drained sandy soils. The ammonia (NH3 emissions exceeded emission targets that were set to protect the biodiversity of nonagricultural land. Improved farming practices were calculated to lead to a significant reduction in NH3 emissions to the atmosphere and N leaching and runoff to groundwater and surface water, but these improvements were not enough to reach all the targets set for those fluxes. Only strong structural measures clearly improved the situation. The NH3 emission target of 30 Gg NH3 year–1, suggested for the year 2030, could not be attained, however, unless pig and poultry farming is completely banned in the Netherlands and all cattle stay almost permanently in low emission stables.

  6. Characterization of Thermal and Mechanical Impact on Aluminum Honeycomb Structures

    Science.gov (United States)

    Robinson, Christen M.

    2013-01-01

    This study supports NASA Kennedy Space Center's research in the area of intelligent thermal management systems and multifunctional thermal systems. This project addresses the evaluation of the mechanical and thermal properties of metallic cellular solid (MCS) materials; those that are lightweight; high strength, tunable, multifunctional and affordable. A portion of the work includes understanding the mechanical properties of honeycomb structured cellular solids upon impact testing under ambient, water-immersed, liquid nitrogen-cooled, and liquid nitrogen-immersed conditions. Additionally, this study will address characterization techniques of the aluminum honeycomb's ability to resist multiple high-rate loadings or impacts in varying environmental conditions, using various techniques for the quantitative and qualitative determination for commercial applicability.

  7. Chesapeake Bay Impact Structure Deep Drilling Project Completes Coring

    Directory of Open Access Journals (Sweden)

    the Scientific Staff of the Chesapeake Bay Impact Structure Deep Drilling Project

    2006-09-01

    Full Text Available The Chesapeake Bay Impact Structure Deep Drilling Project (CBIS Project completed its coring operations during September–December 2005 and April–May 2006. Cores were collected continuously to a total depth of 1766 m. The recovered section consists of 1322 m of impactites beneath 444 m of post-impact continental shelf sediments.The CBIS Project is a joint venture of the International Continental Scientifi c Drilling Program (ICDP and the U.S. Geological Survey (USGS. Project activities began with a planning workshop in September 2003 attended by sixtythree scientists from ten countries. Field operations began with site preparation in July 2005, and coring began in September 2005. Drilling, Observation and Sampling of theEarth’s Continental Crust (DOSECC was the general contractor for the drilling operations throughout 2005.

  8. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Bocock, K.L.

    1981-01-01

    This report summarizes information on the distribution and movement of radionuclides in semi-natural terrestrial ecosystems in north-west England with particular emphasis on inputs to, and outputs from ecosystems; on plant and soil aspects; and on radionuclides in fallout and in discharges by the nuclear industry. (author)

  9. Low temperature impact testing of welded structural wrought iron

    Science.gov (United States)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  10. Proposed law of nature linking impacts, plume volcanism, and Milankovitch cycles to terrestrial vertebrate mass extinctions via greenhouse-embryo death coupling

    Science.gov (United States)

    Mclean, D. M.

    1994-01-01

    A greenhouse-physiological coupling killing mechanism active among mammals, birds, and reptiles has been identified. Operating via environmental thermal effects upon the maternal core-skin blood flow critical to the survival and development of embryos, it reduces the flow of blood to the uterine tract. Today, during hot summers, this phenomena kills embryos on a vast, global scale. Because of sensitivity of many mammals to modern heat, a major modern greenhouse could reduce population numbers on a global scale, and potentially trigger population collapses in the more vulnerable parts of the world. In the geological past, the killing mechanism has likely been triggered into action by greenhouse warming via impact events, plume volcanism, and Earth orbital variations (Milankovitch cycles). Earth's biosphere is maintained and molded by the flow of energy from the solar energy source to Earth and on to the space energy sink (SES). This SES energy flow maintains Earth's biosphere and its living components, as open, intermediate, dissipative, nonequilibrium systems whose states are dependent upon the rate of energy flowing through them. Greenhouse gases such as CO2 in the atmosphere influence the SES energy flow rate. Steady-state flow is necessary for global ecological stability (autopoiesis). Natural fluctuations of the C cycle such as rapid releases of CO2 from the mantle, or oceans, disrupt steady-state SES flow. These fluctuations constantly challenge the biosphere; slowdown of SES energy flow drives it toward thermodynamical equilibrium and stagnation. Fluctuations induced by impact event, mantle plume volcanism, and Milankovitch cycles can grow into structure-breaking waves triggering major perturbations of Earth's C cycle and mass extinctions. A major C cycle perturbation involves readjustment of the outer physiochemical spheres of the Earth: the atmosphere, hydrosphere, and lithosphere; and by necessity, the biosphere. A greenhouse, one manifestation of a major

  11. Airborne and impact sound transmission in super-light structures

    DEFF Research Database (Denmark)

    Christensen, Jacob Ellehauge; Hertz, Kristian Dahl; Brunskog, Jonas

    2011-01-01

    -aggregate concrete. A super-light deck element is developed. It is intended to be lighter than traditional deck structures without compromising the acoustic performance. It is primarily the airborne sound insulation, which is of interest as the requirements for the impact sound insulation to a higher degree can...... be fulfilled by external means such as floorings. The acoustical performance of the slab element is enhanced by several factors. Load carrying internal arches stiffens the element. This causes a decrease in the modal density, which is further improved by the element being lighter. These parameters also...

  12. Microplastics as an emerging threat to terrestrial ecosystems.

    Science.gov (United States)

    de Souza Machado, Anderson Abel; Kloas, Werner; Zarfl, Christiane; Hempel, Stefan; Rillig, Matthias C

    2018-04-01

    Microplastics (plastics plastic litter or from direct environmental emission. Their potential impacts in terrestrial ecosystems remain largely unexplored despite numerous reported effects on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Hence, it is within terrestrial systems that microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems. © 2017 John Wiley & Sons Ltd.

  13. Impact of methionine oxidation on calmodulin structural dynamics

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, Megan R.; Thompson, Andrew R.; Nitu, Florentin [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States); Moen, Rebecca J. [Chemistry and Geology Department, Minnesota State University, Mankato, MN 56001 (United States); Olenek, Michael J. [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Klein, Jennifer C., E-mail: jklein@uwlax.edu [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Thomas, David D., E-mail: ddt@umn.edu [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States)

    2015-01-09

    Highlights: • We measured the distance distribution between two spin labels on calmodulin by DEER. • Two structural states, open and closed, were resolved at both low and high Ca. • Ca shifted the equilibrium toward the open state by a factor of 13. • Methionine oxidation, simulated by glutamine substitution, decreased the Ca effect. • These results have important implications for aging in muscle and other tissues. - Abstract: We have used electron paramagnetic resonance (EPR) to examine the structural impact of oxidizing specific methionine (M) side chains in calmodulin (CaM). It has been shown that oxidation of either M109 or M124 in CaM diminishes CaM regulation of the muscle calcium release channel, the ryanodine receptor (RyR), and that mutation of M to Q (glutamine) in either case produces functional effects identical to those of oxidation. Here we have used site-directed spin labeling and double electron–electron resonance (DEER), a pulsed EPR technique that measures distances between spin labels, to characterize the structural changes resulting from these mutations. Spin labels were attached to a pair of introduced cysteine residues, one in the C-lobe (T117C) and one in the N-lobe (T34C) of CaM, and DEER was used to determine the distribution of interspin distances. Ca binding induced a large increase in the mean distance, in concert with previous X-ray crystallography and NMR data, showing a closed structure in the absence of Ca and an open structure in the presence of Ca. DEER revealed additional information about CaM’s structural heterogeneity in solution: in both the presence and absence of Ca, CaM populates both structural states, one with probes separated by ∼4 nm (closed) and another at ∼6 nm (open). Ca shifts the structural equilibrium constant toward the open state by a factor of 13. DEER reveals the distribution of interprobe distances, showing that each of these states is itself partially disordered, with the width of each

  14. Asset Structure Impact on Capital Structure of Capital Market-Listed Firms in Indonesia and Malaysia

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Sahabuddin

    2017-07-01

    Full Text Available Debt was able to be used by firm as source of funds for investment-related activities,especially when the amount of retained earnings was not sufficient to cover the amount of investment needed. Naturally, the use of debt definitely caused the agency conflict between firm shareholders and debt holders. To reduce this conflict, the existence of fixed assets as collateral was needed when firm decided to borrow money from debt holders.The purpose of this study was to prove the agency theory perspective by testing an impact of asset structure on capital structure of firms. The population of this study was the firms listed on Indonesia Stock Exchange and Malaysian Stock Exchange. The firms as sample were taken from the population by conducting stratified random sampling method. The pooled data regression model was used as the data analysis method. This result of this study showed that asset structure had the positive impact on capital structure. It meant the causal relationship between asset structure and capital structure happened and was supported by the agency theory perspective.

  15. Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

    Science.gov (United States)

    Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

    2017-12-01

    Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

  16. Structural modeling of the Vichada impact structure from interpreted ground gravity and magnetic anomalies

    International Nuclear Information System (INIS)

    Hernandez, Orlando; Khurama, Sait; Alexander, Gretta C

    2011-01-01

    A prominent positive free-air gravity anomaly mapped over a roughly 50-km diameter basin is consistent with a mascon centered on (4 degrades 30 minutes N, 69 degrades 15 minutes W) in the Vichada Department, Colombia, South America. Ground follow up gravity and magnetic anomalies were modeled confirming the regional free air gravity anomalies. These potential field anomalies infer a hidden complex impact basin structure filled with tertiary sedimentary rocks and recent quaternary deposits. Negative Bouguer anomalies of 8 mgals to 15 mgals amplitude are associated with a concentric sedimentary basin with a varying thickness from 100 m to 500 m in the outer rings to 700 m to 1000 m at the center of the impact crater basin. Strong positive magnetic anomalies of 100 nt to 300 nt amplitude infer the presence of a local Precambrian crystalline basement that was affected by intensive faulting producing tectonic blocks dipping to the center of the structure, showing a typical domino structure of impact craters such as that of Sudbury, Ontario, Canada. Basic to intermediate mineralized veins and dikes with contrasting density and magnetic susceptibility properties could be emplaced along these faulting zones, as inferred from local gravity and magnetic highs. The geologic mapping of the area is limited by the flat topography and absence of outcrops/ geomorphologic units. Nevertheless, local normal faults along the inner ring together with radially sparse irregular blocks over flat terrains can be associated with terraced rims or collapse of the inner crater structure and eject blanket, respectively. A detailed airborne electromagnetic survey is recommended to confirm the gravity and magnetic anomalies together with a seismic program to evaluate the economic implications for energy and mineral exploration of the Vichada impact structure.

  17. Furostanol and Spirostanol Saponins from Tribulus terrestris.

    Science.gov (United States)

    Wang, Zhen-Fang; Wang, Bing-Bing; Zhao, Yang; Wang, Fang-Xu; Sun, Yan; Guo, Rui-Jie; Song, Xin-Bo; Xin, Hai-Li; Sun, Xin-Guang

    2016-03-30

    Twelve new steroidal saponins, including eleven furostanol saponins, terrestrinin J-T (1-11), and one spirostanol saponin, terrestrinin U (12), together with seven known steroidal saponins 13-19 were isolated from T. terrestris. The structures of the new compounds were established on the basis of spectroscopic data, including 1D and 2D NMR and HRESIMS, and comparisons with published data.

  18. Structural Composite Supercapacitors: Electrical and Mechanical Impact of Separators and Processing Conditions

    Science.gov (United States)

    2013-09-01

    Structural Composite Supercapacitors : Electrical and Mechanical Impact of Separators and Processing Conditions by Edwin B. Gienger, James F...Proving Ground, MD 21005-5066 ARL-TR-6624 September 2013 Structural Composite Supercapacitors : Electrical and Mechanical Impact of...2012 4. TITLE AND SUBTITLE Structural Composite Supercapacitors : Electrical and Mechanical Impact of Separators and Processing Conditions 5a

  19. Long-term efficiency of soil stabilization with apatite and Slovakite: the impact of two earthworm species (Lumbricus terrestris and Dendrobaena veneta) on lead bioaccessibility and soil functioning.

    Science.gov (United States)

    Tica, D; Udovic, M; Lestan, D

    2013-03-01

    Remediation soil is exposed to various environmental factors over time that can affect the final success of the operation. In the present study, we assessed Pb bioaccessibility and microbial activity in industrially polluted soil (Arnoldstein, Austria) stabilized with 5% (w/w) of Slovakite and 5% (w/w) of apatite soil after exposure to two earthworm species, Lumbricus terrestris and Dendrobaena veneta, used as model environmental biotic soil factors. Stabilization resulted in reduced Pb bioaccessibility, as assessed with one-step extraction tests and six-step sequential extraction, and improved soil functioning, mirrored in reduced β-glucosidase activity in soil. Both earthworm species increased Pb bioaccessibility, thus decreasing the initial stabilization efficacy and indicating the importance of considering the long-term fate of remediated soil. The earthworm species had different effects on soil enzyme activity, which can be attributed to species-specific microbial populations in earthworm gut acting on the ingested soil. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Network Structure as a Modulator of Disturbance Impacts in Streams

    Science.gov (United States)

    Warner, S.; Tullos, D. D.

    2017-12-01

    This study examines how river network structure affects the propagation of geomorphic and anthropogenic disturbances through streams. Geomorphic processes such as debris flows can alter channel morphology and modify habitat for aquatic biota. Anthropogenic disturbances such as road construction can interact with the geomorphology and hydrology of forested watersheds to change sediment and water inputs to streams. It was hypothesized that the network structure of streams within forested watersheds would influence the location and magnitude of the impacts of debris flows and road construction on sediment size and channel width. Longitudinal surveys were conducted every 50 meters for 11 kilometers of third-to-fifth order streams in the H.J. Andrews Experimental Forest in the Western Cascade Range of Oregon. Particle counts and channel geometry measurements were collected to characterize the geomorphic impacts of road crossings and debris flows as disturbances. Sediment size distributions and width measurements were plotted against the distance of survey locations through the network to identify variations in longitudinal trends of channel characteristics. Thresholds for the background variation in sediment size and channel width, based on the standard deviations of sample points, were developed for sampled stream segments characterized by location as well as geomorphic and land use history. Survey locations were classified as "disturbed" when they deviated beyond the reference thresholds in expected sediment sizes and channel widths, as well as flow-connected proximity to debris flows and road crossings. River network structure was quantified by drainage density and centrality of nodes upstream of survey locations. Drainage density and node centrality were compared between survey locations with similar channel characteristic classifications. Cluster analysis was used to assess the significance of survey location, proximity of survey location to debris flows and road

  1. Phytopharmacology of Tribulus terrestris.

    Science.gov (United States)

    Shahid, M; Riaz, M; Talpur, M M A; Pirzada, T

    2016-01-01

    Tribulus terrestris is an annual herb which belongs to the Zygophyllaceae family. This plant has been used in traditional medicine for the treatment of various diseases for hundreds of decades. The main active phytoconstituents of this plant include flavonoids, alkaloids, saponins, lignin, amides, and glycosides. The plant parts have different pharmacological activities including aphrodisiac, antiinflammatory, antimicrobial and antioxidant potential. T. terrestris is most often used for infertility and loss of libido. It has potential application as immunomodulatory, hepatoprotective, hypolipidemic, anthelmintic and anticarcinogenic activities. The aim of the present article is to create a database for further investigation of the phytopharmacological properties of this plant to promote research. This study will definitely help to confirm its traditional use along with its value-added utility, eventually leading to higher revenues from the plant.

  2. Terrestrial plant methane production

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Møller, Ian M.

    We evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants. We conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH4 production, i.e. cutting injuries, increasing temperature...... the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  3. THE IMPACT OF OVERCONFIDENCE ON CAPITAL STRUCTURE IN TURKEY

    Directory of Open Access Journals (Sweden)

    Serpil Tomak

    2013-04-01

    Full Text Available The aim of this study is to investigate the relationship between the overconfidence and capital structure in Turkish manufacturing firms. In addition to management confidence, the impact of the fundamental factors on the market leverage is analyzed. The annual data of 115 manufacturing firms on the Istanbul Stock Exchange (ISE for the period between 2002 and 2011 is used for the analysis by means of the ordinary least squares regression model. The results show that the relationship between confidence and leverage is ambiguous. There isn’t enough evidence for the idea of overconfident managers tends to use more debt level. However, this study provides some evidence for firm specific factors like size and profitability effects on leverage.

  4. The Ecology of Seamounts: Structure, Function, and Human Impacts

    Science.gov (United States)

    Clark, Malcolm R.; Rowden, Ashley A.; Schlacher, Thomas; Williams, Alan; Consalvey, Mireille; Stocks, Karen I.; Rogers, Alex D.; O'Hara, Timothy D.; White, Martin; Shank, Timothy M.; Hall-Spencer, Jason M.

    2010-01-01

    In this review of seamount ecology, we address a number of key scientific issues concerning the structure and function of benthic communities, human impacts, and seamount management and conservation. We consider whether community composition and diversity differ between seamounts and continental slopes, how important dispersal capabilities are in seamount connectivity, what environmental factors drive species composition and diversity, whether seamounts are centers of enhanced biological productivity, and whether they have unique trophic architecture. We discuss how vulnerable seamount communities are to fishing and mining, and how we can balance exploitation of resources and conservation of habitat. Despite considerable advances in recent years, there remain many questions about seamount ecosystems that need closer integration of molecular, oceanographic, and ecological research.

  5. Ancient Terrestrial Carbon: Lost and Found

    Science.gov (United States)

    Freeman, K. H.

    2017-12-01

    Carbon fluxes in terrestrial environments dominate the global carbon cycle. The fluxes of terrestrial carbon are strongly tied to regional climate due to the influences of temperature, water, and nutrient dynamics on plant productivity. However, climate also influences the destruction of terrestrial organic matter, through weathering, erosion, and biomass loss via fire and oxidative microbial processes. Organic geochemical methods enable us to interrogate past terrestrial carbon dynamics and learn how continental processes might accelerate, or mitigate carbon transfer to the atmosphere, and the associated greenhouse warming. Terrestrial soil systems represent the weathering rind of the continents, and are inherently non-depositional and erosive. The production, transport, and depositional processes affecting organics in continental settings each impart their own biases on the amount and characteristics of preserved carbon. Typically, the best archives for biomarker records are sediments in ancient lakes or subaqueous fans, which represents a preservation bias that tends to favor wetter environments. Paleosols, or ancient soils, formed under depositional conditions that, for one reason or another, truncated soil ablation, erosion, or other loss processes. In modern soils, widely ranging organic carbon abundances are almost always substantially greater than the trace amounts of carbon left behind in ancient soils. Even so, measureable amounts of organic biomarkers persist in paleosols. We have been investigating processes that preserve soil organic carbon on geologic timescales, and how these mechanisms may be sensitive to past climate change. Climate-linked changes in temperature, moisture, pH, and weathering processes can impact carbon preservation via organo-mineral sorption, soil biogeochemistry, and stability based on the physical and chemical properties of organic compounds. These will be discussed and illustrated with examples from our studies of Cenozoic

  6. Comparative Climatology of Terrestrial Planets

    Science.gov (United States)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    Public awareness of climate change on Earth is currently very high, promoting significant interest in atmospheric processes. We are fortunate to live in an era where it is possible to study the climates of many planets, including our own, using spacecraft and groundbased observations as well as advanced computational power that allows detailed modeling. Planetary atmospheric dynamics and structure are all governed by the same basic physics. Thus differences in the input variables (such as composition, internal structure, and solar radiation) among the known planets provide a broad suite of natural laboratory settings for gaining new understanding of these physical processes and their outcomes. Diverse planetary settings provide insightful comparisons to atmospheric processes and feedbacks on Earth, allowing a greater understanding of the driving forces and external influences on our own planetary climate. They also inform us in our search for habitable environments on planets orbiting distant stars, a topic that was a focus of Exoplanets, the preceding book in the University of Arizona Press Space Sciences Series. Quite naturally, and perhaps inevitably, our fascination with climate is largely driven toward investigating the interplay between the early development of life and the presence of a suitable planetary climate. Our understanding of how habitable planets come to be begins with the worlds closest to home. Venus, Earth, and Mars differ only modestly in their mass and distance from the Sun, yet their current climates could scarcely be more divergent. Our purpose for this book is to set forth the foundations for this emerging science and to bring to the forefront our current understanding of atmospheric formation and climate evolution. Although there is significant comparison to be made to atmospheric processes on nonterrestrial planets in our solar system — the gas and ice giants — here we focus on the terrestrial planets, leaving even broader comparisons

  7. Terrestrial gamma-ray flashes

    Science.gov (United States)

    Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

    2013-08-01

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models.

  8. Terrestrial gamma-ray flashes

    International Nuclear Information System (INIS)

    Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

    2013-01-01

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models

  9. The Solar-Terrestrial Environment

    Science.gov (United States)

    Hargreaves, John Keith

    1995-05-01

    The book begins with three introductory chapters that provide some basic physics and explain the principles of physical investigation. The principal material contained in the main part of the book covers the neutral and ionized upper atmosphere, the magnetosphere, and structures, dynamics, disturbances, and irregularities. The concluding chapter deals with technological applications. The account is introductory, at a level suitable for readers with a basic background in engineering or physics. The intent is to present basic concepts, and for that reason, the mathematical treatment is not complex. SI units are given throughout, with helpful notes on cgs units where these are likely to be encountered in the research literature. This book is suitable for advanced undergraduate and graduate students who are taking introductory courses on upper atmospheric, ionospheric, or magnetospheric physics. This is a successor to The Upper Atmosphere and Solar-Terrestrial Relations, published in 1979.

  10. The early evolution of the atmospheres of terrestrial planets

    CERN Document Server

    Raulin, François; Muller, Christian; Nixon, Conor; Astrophysics and Space Science Proceedings : Volume 35

    2013-01-01

    “The Early Evolution of the Atmospheres of Terrestrial Planets” presents the main processes participating in the atmospheric evolution of terrestrial planets. A group of experts in the different fields provide an update of our current knowledge on this topic. Several papers in this book discuss the key role of nitrogen in the atmospheric evolution of terrestrial planets. The earliest setting and evolution of planetary atmospheres of terrestrial planets is directly associated with accretion, chemical differentiation, outgassing, stochastic impacts, and extremely high energy fluxes from their host stars. This book provides an overview of the present knowledge of the initial atmospheric composition of the terrestrial planets. Additionally it includes some papers about the current exoplanet discoveries and provides additional clues to our understanding of Earth’s transition from a hot accretionary phase into a habitable world. All papers included were reviewed by experts in their respective fields. We are ...

  11. High resolution measurement of earthquake impacts on rock slope stability and damage using pre- and post-earthquake terrestrial laser scans

    Science.gov (United States)

    Hutchinson, Lauren; Stead, Doug; Rosser, Nick

    2017-04-01

    Understanding the behaviour of rock slopes in response to earthquake shaking is instrumental in response and relief efforts following large earthquakes as well as to ongoing risk management in earthquake affected areas. Assessment of the effects of seismic shaking on rock slope kinematics requires detailed surveys of the pre- and post-earthquake condition of the slope; however, at present, there is a lack of high resolution monitoring data from pre- and post-earthquake to facilitate characterization of seismically induced slope damage and validate models used to back-analyze rock slope behaviour during and following earthquake shaking. Therefore, there is a need for additional research where pre- and post- earthquake monitoring data is available. This paper presents the results of a direct comparison between terrestrial laser scans (TLS) collected in 2014, the year prior to the 2015 earthquake sequence, with that collected 18 months after the earthquakes and two monsoon cycles. The two datasets were collected using Riegl VZ-1000 and VZ-4000 full waveform laser scanners with high resolution (c. 0.1 m point spacing as a minimum). The scans cover the full landslide affected slope from the toe to the crest. The slope is located in Sindhupalchok District, Central Nepal which experienced some of the highest co-seismic and post-seismic landslide intensities across Nepal due to the proximity to the epicenters (<20 km) of both of the main aftershocks on April 26, 2015 (M 6.7) and May 12, 2015 (M7.3). During the 2015 earthquakes and subsequent 2015 and 2016 monsoons, the slope experienced rockfall and debris flows which are evident in satellite imagery and field photographs. Fracturing of the rock mass associated with the seismic shaking is also evident at scales not accessible through satellite and field observations. The results of change detection between the TLS datasets with an emphasis on quantification of seismically-induced slope damage is presented. Patterns in the

  12. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP......-Terrestrial Plan/the Plan) as the framework for coordinated, long-term Arctic terrestrial biodiversity monitoring. The goal of the CBMP-Terrestrial Plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect, understand and report on long...

  13. Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

    Science.gov (United States)

    Walton, E. L.; Sharp, T. G.; Hu, J.; Tschauner, O.

    2018-01-01

    Impact metamorphic effects from quartz and feldspar and to a lesser extent olivine and pyroxene have been studied in detail. Comparatively, studies documenting shock effects in other minerals, such as double chain inosilicates, phyllosilicates, carbonates, and sulfates, are lacking. In this study, we investigate impact metamorphism recorded in crystalline basement rocks from the Steen River impact structure (SRIS), a 25 km diameter complex crater in NW Alberta, Canada. An array of advanced analytical techniques was used to characterize the breakdown of biotite in two distinct settings: along the margins of localized regions of shock melting and within granitic target rocks entrained as clasts in a breccia. In response to elevated temperature gradients along shock vein margins, biotite transformed at high pressure to an almandine-Ca/Fe majorite-rich garnet with a density of 4.2 g cm-3. The shock-produced garnets are poikilitic, with oxide and silicate glass inclusions. Areas interstitial to garnets are vesiculated, in support of models for the formation of shock veins via oscillatory slip, with deformation continuing during pressure release. Biotite within granitic clasts entrained within the hot breccia matrix thermally decomposed at ambient pressure to produce a fine-grained mineral assemblage of orthopyroxene + sanidine + titanomagnetite. These minerals are aligned to the (001) cleavage plane of the original crystal. In this and previous work, the transformation of an inosilicate (pargasite) and a phyllosilicate (biotite) to form garnet, an easily identifiable, robust mineral, has been documented. We contend that in deeply eroded astroblemes, high-pressure minerals that form within or in the environs of shock veins may serve as one of the possibly few surviving indicators of impact metamorphism.

  14. Contaminant exposure in terrestrial vertebrates

    International Nuclear Information System (INIS)

    Smith, Philip N.; Cobb, George P.; Godard-Codding, Celine; Hoff, Dale; McMurry, Scott T.; Rainwater, Thomas R.; Reynolds, Kevin D.

    2007-01-01

    Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Chemical fate and transport in the environment determine contaminant bioaccessibility. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. We review limitations in our understanding of elements of exposure and the unique aspects of exposure associated with terrestrial and semi-terrestrial taxa. We provide insight on taxa-specific traits that contribute, or limit exposure to, transport phenomenon that influence exposure throughout terrestrial systems, novel contaminants, bioavailability, exposure data analysis, and uncertainty associated with exposure in wildlife risk assessments. Lastly, we identify areas related to exposure among terrestrial and semi-terrestrial organisms that warrant additional research. - Both biotic and abiotic factors determine chemical exposure for terrestrial vertebrates

  15. Change in atmospheric deposition during last half century and its impact on lichen community structure in Eastern Himalaya.

    Science.gov (United States)

    Bajpai, Rajesh; Mishra, Seema; Dwivedi, Sanjay; Upreti, Dalip Kumar

    2016-08-09

    Climatic fluctuations largely affects species turnover and cause major shifts of terrestrial ecosystem. In the present study the five decade old herbarium specimens of lichens were compared with recent collection from Darjeeling district with respect to elements, PAHs accumulation and carbon isotope composition (δ(13)C) to explore the changes in climatic conditions and its impact on lichen flora. The δ(13)C has increased in recent specimens which is in contrast to the assumption that anthropogenic emission leads to δ(13)C depletion in air and increased carbon discrimination in flora. Study clearly demonstrated an increase in anthropogenic pollution and drastic decrease in precipitation while temperature showed abrupt changes during the past five decades resulting in significant change in lichen community structure. The Usneoid and Pertusorioid communities increased, while Physcioid and Cyanophycean decreased, drastically. Lobarian abolished from the study area, however, Calcicoid has been introduced in the recent past. Probably, post-industrial revolution, the abrupt changes in the environment has influenced CO2 diffusion and/C fixation of (lower) plants either as an adaptation strategy or due to toxicity of pollutants. Thus, the short term studies (≤5 decades) might reflect recent micro-environmental condition and lichen community structure can be used as model to study the global climate change.

  16. Change in atmospheric deposition during last half century and its impact on lichen community structure in Eastern Himalaya

    Science.gov (United States)

    Bajpai, Rajesh; Mishra, Seema; Dwivedi, Sanjay; Upreti, Dalip Kumar

    2016-08-01

    Climatic fluctuations largely affects species turnover and cause major shifts of terrestrial ecosystem. In the present study the five decade old herbarium specimens of lichens were compared with recent collection from Darjeeling district with respect to elements, PAHs accumulation and carbon isotope composition (δ13C) to explore the changes in climatic conditions and its impact on lichen flora. The δ13C has increased in recent specimens which is in contrast to the assumption that anthropogenic emission leads to δ13C depletion in air and increased carbon discrimination in flora. Study clearly demonstrated an increase in anthropogenic pollution and drastic decrease in precipitation while temperature showed abrupt changes during the past five decades resulting in significant change in lichen community structure. The Usneoid and Pertusorioid communities increased, while Physcioid and Cyanophycean decreased, drastically. Lobarian abolished from the study area, however, Calcicoid has been introduced in the recent past. Probably, post-industrial revolution, the abrupt changes in the environment has influenced CO2 diffusion and/C fixation of (lower) plants either as an adaptation strategy or due to toxicity of pollutants. Thus, the short term studies (≤5 decades) might reflect recent micro-environmental condition and lichen community structure can be used as model to study the global climate change.

  17. Terrestrial forest management plan for Palmyra Atoll

    Science.gov (United States)

    Hathaway, Stacie A.; McEachern, Kathryn; Fisher, Robert N.

    2011-01-01

    , and though rarely documented, beach nesting could be affected by terrestrial management actions. There are various nonnative or invasive species throughout the terrestrial ecosystem. The most notable examples of terrestrial invasive species include coconut palms (Cocos nucifera) and black rats (Rattus rattus). Although it is unclear whether they are nonnative, coconut palms are currently the most dominant plant across Palmyra Atoll. They compete with native plant species for space and resources and are potentially detrimental to sea birds dependent on native vegetation for roosting and nesting habitat. This competition in turn impacts nutrient resource availability, thereby reshaping energy flow in the ecosystem. Black rats are known to prey on ground-nesting sea birds and are likely responsible for the lack of burrowing sea bird reproduction at Palmyra Atoll. In addition, they may be facilitating the invasion of other nonnative species and negatively impacting other native fauna. Although the extent and impacts of these and other nonnative and (or) invasive species are not fully understood, the extent and impacts are clearly a threat to the native species and one of the most urgent threats to the overall ecosystem integrity of Palmyra Atoll. This 'Terrestrial Forest Management Plan for Palmyra Atoll' addresses issues related to invasive species and other problems. Priority goals are established as are associated objectives and strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem integrity through the following techniques: 1. Habitat management: Maintain and enhance habitat to the extent possible to sustain thriving Pisonia grandis forest, coastal strand forest, endemic grassland, self-sustaining populations of sea birds, shore birds, coconut crabs, native lizards, and native insects. 2. Monitoring and assessment: Acquire information on distribution and abundance as needed for conservation of each resour

  18. The terrestrial biosphere in the SFR region

    Energy Technology Data Exchange (ETDEWEB)

    Jerling, L; Isaeus, M [Stockholm Univ. (Sweden). Dept. of Botany; Lanneck, J [Stockholm Univ. (Sweden). Dept. of Physical Geography; Lindborg, T; Schueldt, R [Danish Nature Council, Copenhagen (Denmark)

    2001-03-01

    coarse model of the future vegetation. To make this fully clear we have included a description of past development of environmental conditions and vegetation as a key to understand the discrepancy between past events and predictions of the future. Thus, the part dealing with the development of vegetation is started by a description of the past, followed by a prediction of future vegetation. The history of vegetation shows that the development is an interaction between changes in climate, shore displacement,local vegetation development and human activities. Differences in plant community structure can, to a large extent, be related to climatic change. When it got warmer and more humid, nemoral (thermophilus) species immigrated, and the distribution of land classes changed on a regional scale. The most important factors for the change of the biotic environment and plant community has been human impact and climate change, while shore displacement rather has an effect locally and on a short time scale. In the premises for future development of vegetation, change in climate and most of human activities are omitted. A general outline of the anticipated future development of the vegetation is described. There will be a major change in the vegetation of the area from year 3000 to 4000 in that vast areas will be transformed from aquatic to terrestrial. This probably means that new accumulation areas for water transported materials are formed. With the transformation from aquatic to terrestrial environment more stable sinks will be formed such as lakes and mires. In these, organic material will be accumulated and carbon will be concentrated to particular areas. In year 5000 practically no aquatic areas are to be found and at this stage very small amount of organic material will leave the area except by water transport and by gases. Since the mobility is higher in dryer areas where the organic material is decomposed at a faster rate one will expect an increased mobility whereas in

  19. The terrestrial biosphere in the SFR region

    International Nuclear Information System (INIS)

    Jerling, L.; Isaeus, M.

    2001-03-01

    model of the future vegetation. To make this fully clear we have included a description of past development of environmental conditions and vegetation as a key to understand the discrepancy between past events and predictions of the future. Thus, the part dealing with the development of vegetation is started by a description of the past, followed by a prediction of future vegetation. The history of vegetation shows that the development is an interaction between changes in climate, shore displacement,local vegetation development and human activities. Differences in plant community structure can, to a large extent, be related to climatic change. When it got warmer and more humid, nemoral (thermophilus) species immigrated, and the distribution of land classes changed on a regional scale. The most important factors for the change of the biotic environment and plant community has been human impact and climate change, while shore displacement rather has an effect locally and on a short time scale. In the premises for future development of vegetation, change in climate and most of human activities are omitted. A general outline of the anticipated future development of the vegetation is described. There will be a major change in the vegetation of the area from year 3000 to 4000 in that vast areas will be transformed from aquatic to terrestrial. This probably means that new accumulation areas for water transported materials are formed. With the transformation from aquatic to terrestrial environment more stable sinks will be formed such as lakes and mires. In these, organic material will be accumulated and carbon will be concentrated to particular areas. In year 5000 practically no aquatic areas are to be found and at this stage very small amount of organic material will leave the area except by water transport and by gases. Since the mobility is higher in dryer areas where the organic material is decomposed at a faster rate one will expect an increased mobility whereas in

  20. The terrestrial biosphere in the SFR region

    Energy Technology Data Exchange (ETDEWEB)

    Jerling, L.; Isaeus, M. [Stockholm Univ. (Sweden). Dept. of Botany; Lanneck, J. [Stockholm Univ. (Sweden). Dept. of Physical Geography; Lindborg, T.; Schueldt, R. [Danish Nature Council, Copenhagen (Denmark)

    2001-03-01

    in a coarse model of the future vegetation. To make this fully clear we have included a description of past development of environmental conditions and vegetation as a key to understand the discrepancy between past events and predictions of the future. Thus, the part dealing with the development of vegetation is started by a description of the past, followed by a prediction of future vegetation. The history of vegetation shows that the development is an interaction between changes in climate, shore displacement,local vegetation development and human activities. Differences in plant community structure can, to a large extent, be related to climatic change. When it got warmer and more humid, nemoral (thermophilus) species immigrated, and the distribution of land classes changed on a regional scale. The most important factors for the change of the biotic environment and plant community has been human impact and climate change, while shore displacement rather has an effect locally and on a short time scale. In the premises for future development of vegetation, change in climate and most of human activities are omitted. A general outline of the anticipated future development of the vegetation is described. There will be a major change in the vegetation of the area from year 3000 to 4000 in that vast areas will be transformed from aquatic to terrestrial. This probably means that new accumulation areas for water transported materials are formed. With the transformation from aquatic to terrestrial environment more stable sinks will be formed such as lakes and mires. In these, organic material will be accumulated and carbon will be concentrated to particular areas. In year 5000 practically no aquatic areas are to be found and at this stage very small amount of organic material will leave the area except by water transport and by gases. Since the mobility is higher in dryer areas where the organic material is decomposed at a faster rate one will expect an increased mobility

  1. Impact of ATLAS measurements on the knowledge of proton structure

    CERN Document Server

    Gwenlan, Claire; The ATLAS collaboration

    2016-01-01

    Several measurements performed by the ATLAS collaboration can be used to constrain the proton structure. Measurements of the W+c production and the inclusive W and Z differential cross sections are found to constrain the poorly known strange-quark density at low x. Similarly, the ratio of W+/W- production is found to constrain the valence quarks at low x. New results will be presented using W,Z production at 13 TeV. New precise measurements of Drell-Yan cross section measurements performed above the Z peak region have a different sensitivity to parton flavour, parton momentum fraction x and scale Q compared to measurements on the Z peak. A large impact is found on the photon content of the proton as well as high x quarks. Measurements of the inclusive jet and photon cross sections are standard candles and constrain the medium and high x gluon densities. New precise measurements of inclusive photon and jet cross sections at 8 TeV are presented and compared to various PDF predictions.

  2. Impact of Corrugated Paperboard Structure on Puncture Resistance

    Directory of Open Access Journals (Sweden)

    Vaidas Bivainis

    2015-03-01

    Full Text Available Thanks to its excellentprotective properties, lightness, a reasonable price, and ecology, corrugated paperboardis one of the most popular materials used in the production of packaging for variousproducts. During transportation or storage, packaging with goods can be exposedto the mass of other commodities, dropping from heights and transportationshock loads, which can lead to their puncture damage. Depending on the purposeand size of the packaging, the thickness, grammage, constituent paper layers,numbers of layers and type of fluting of corrugated paperboard used in itsproduction differ. A standard triangular prism, corrugated paperboard fixationplates and a universal tension-compression machine were used to investigate theimpact of corrugated paperboard structure and other parameters on the punctureresistance of the material. The investigation determines the maximum punctureload and estimates energy required to penetrate the corrugated paperboard. Itwas found that the greatest puncture resistance is demonstrated by paperboardwith a larger number of corrugating flutings and the board produced from harderpaper with a smaller amount of recycled paper. It was established that thegrammage of three-layered paperboard with two different fluting profiles has thegreatest impact on the level of static puncture energy.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5713

  3. The Impact of Microphysics on Intensity and Structure of Hurricanes

    Science.gov (United States)

    Tao, Wei-Kuo; Shi, Jainn; Lang, Steve; Peters-Lidard, Christa

    2006-01-01

    During the past decade, both research and operational numerical weather prediction models, e.g. Weather Research and Forecast (WRF) model, have started using more complex microphysical schemes originally developed for high-resolution cloud resolving models (CRMs) with a 1-2 km or less horizontal resolutions. WFW is a next-generation mesoscale forecast model and assimilation system that has incorporated modern software framework, advanced dynamics, numeric and data assimilation techniques, a multiple moveable nesting capability, and improved physical packages. WFW model can be used for a wide range of applications, from idealized research to operational forecasting, with an emphasis on horizontal grid sizes in the range of 1-10 km. The current WRF includes several different microphysics options such as Lin et al. (1983), WSM 6-class and Thompson microphysics schemes. We have recently implemented three sophisticated cloud microphysics schemes into WRF. The cloud microphysics schemes have been extensively tested and applied for different mesoscale systems in different geographical locations. The performances of these schemes have been compared to those from other WRF microphysics options. We are performing sensitivity tests in using WW to examine the impact of six different cloud microphysical schemes on hurricane track, intensity and rainfall forecast. We are also performing the inline tracer calculation to comprehend the physical processes @e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes.

  4. Terrestrial Water Storage

    Science.gov (United States)

    Rodell, M.; Chambers, D. P.; Famiglietti, J. S.

    2015-01-01

    During 2014 dryness continued in the Northern Hemisphere and relative wetness continued in the Southern Hemisphere (Fig. 2.21; Plate 2.1g). These largely canceled out such that the global land surface began and ended the year with a terrestrial water storage (TWS) anomaly slightly below 0 cm (equivalent height of water; Fig. 2.22). TWS is the sum of groundwater, soil moisture, surface water, snow, and ice. Groundwater responds more slowly to meteorological phenomena than the other components because the overlying soil acts as a low pass filter, but often it has a larger range of variability on multiannual timescales (Rodell and Famiglietti 2001; Alley et al. 2002).In situ groundwater data are only archived and made and Tanzania. The rest of the continent experienced mixed to dry conditions. Significant reductions in TWS in Greenland, Antarctica, and southern coastal Alaska reflect ongoing ice sheet and glacier ablation, not groundwater depletion.

  5. Impact of terrestrial mining and intensive agriculture in pollution of estuarine surface sediments: Spatial distribution of trace metals in the Gulf of Urabá, Colombia.

    Science.gov (United States)

    Vallejo Toro, Pedro Pablo; Vásquez Bedoya, Luis Fernando; Correa, Iván Darío; Bernal Franco, Gladys Rocío; Alcántara-Carrió, Javier; Palacio Baena, Jaime Alberto

    2016-10-15

    The Gulf of Urabá (northwestern Colombia) is a geostrategic region, rich in biodiversity and natural resources. Its economy is mainly based on agribusinesses and mining activities. In this research is determined the impact of these activities in bottom surface sediments of the estuary. Thus, grain size, total organic carbon, total nitrogen, carbonates, Ag, Al, Ca, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb and Zn concentrations from 17 surface sediment samples were obtained and enrichment factors (EF) as well as geo-accumulation indices (Igeo) were calculated to determine the contamination level in the gulf. EF and Igeo values revealed that the estuary is extremely contaminated with Ag and moderately contaminated with Zn. Therefore, the observed enrichment of Ag may be explained as a residue of the extraction of gold and platinum-group metals and the enrichment with Zn associated mainly to pesticides used in banana plantations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. New Investigations of the Gow Lake Impact Structure, Saskatchewan, Canada: Impact Melt Rocks, Astronaut Training, and More

    Science.gov (United States)

    Osinski, G. R.; Singleton, A. C.; Ozaruk, A.; Hansen, J. R.

    2012-03-01

    New investigations of the Gow Lake impact structure has revealed an almost complete sequence of impactites from the crater floor upward through a series of melt-free and melt-bearing rocks. This research involved an astronaut training component.

  7. The Origin of the Moon Within a Terrestrial Synestia

    Science.gov (United States)

    Lock, Simon J.; Stewart, Sarah T.; Petaev, Michail I.; Leinhardt, Zoë; Mace, Mia T.; Jacobsen, Stein B.; Cuk, Matija

    2018-04-01

    The giant impact hypothesis remains the leading theory for lunar origin. However, current models struggle to explain the Moon's composition and isotopic similarity with Earth. Here we present a new lunar origin model. High-energy, high-angular-momentum giant impacts can create a post-impact structure that exceeds the corotation limit, which defines the hottest thermal state and angular momentum possible for a corotating body. In a typical super-corotation-limit body, traditional definitions of mantle, atmosphere, and disk are not appropriate, and the body forms a new type of planetary structure, named a synestia. Using simulations of cooling synestias combined with dynamic, thermodynamic, and geochemical calculations, we show that satellite formation from a synestia can produce the main features of our Moon. We find that cooling drives mixing of the structure, and condensation generates moonlets that orbit within the synestia, surrounded by tens of bars of bulk silicate Earth vapor. The moonlets and growing moon are heated by the vapor until the first major element (Si) begins to vaporize and buffer the temperature. Moonlets equilibrate with bulk silicate Earth vapor at the temperature of silicate vaporization and the pressure of the structure, establishing the lunar isotopic composition and pattern of moderately volatile elements. Eventually, the cooling synestia recedes within the lunar orbit, terminating the main stage of lunar accretion. Our model shifts the paradigm for lunar origin from specifying a certain impact scenario to achieving a Moon-forming synestia. Giant impacts that produce potential Moon-forming synestias were common at the end of terrestrial planet formation.

  8. Impacts on terrestrial biodiversity of moving from a 2°C to a 1.5°C target

    Science.gov (United States)

    Price, Jeff; Molotoks, Amy; Warren, Rachel

    2018-01-01

    We applied a recently developed tool to examine the reduction in climate risk to biodiversity in moving from a 2°C to a 1.5°C target. We then reviewed the recent literature examining the impact of (a) land-based mitigation options and (b) land-based greenhouse gas removal options on biodiversity. We show that holding warming to 1.5°C versus 2°C can significantly reduce the number of species facing a potential loss of 50% of their climatic range. Further, there would be an increase of 5.5–14% of the globe that could potentially act as climatic refugia for plants and animals, an area equivalent to the current global protected area network. Efforts to meet the 1.5°C target through mitigation could largely be consistent with biodiversity protection/enhancement. For impacts of land-based greenhouse gas removal technologies on biodiversity, some (e.g. soil carbon sequestration) could be neutral or positive, others (e.g. bioenergy with carbon capture and storage) are likely to lead to conflicts, while still others (e.g. afforestation/reforestation) are context-specific, when applied at scales necessary for meaningful greenhouse gas removal. Additional effort to meet the 1.5°C target presents some risks, particularly if inappropriately managed, but it also presents opportunities. This article is part of the theme issue ‘The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'. PMID:29610386

  9. Impacts on terrestrial biodiversity of moving from a 2°C to a 1.5°C target

    Science.gov (United States)

    Smith, Pete; Price, Jeff; Molotoks, Amy; Warren, Rachel; Malhi, Yadvinder

    2018-05-01

    We applied a recently developed tool to examine the reduction in climate risk to biodiversity in moving from a 2°C to a 1.5°C target. We then reviewed the recent literature examining the impact of (a) land-based mitigation options and (b) land-based greenhouse gas removal options on biodiversity. We show that holding warming to 1.5°C versus 2°C can significantly reduce the number of species facing a potential loss of 50% of their climatic range. Further, there would be an increase of 5.5-14% of the globe that could potentially act as climatic refugia for plants and animals, an area equivalent to the current global protected area network. Efforts to meet the 1.5°C target through mitigation could largely be consistent with biodiversity protection/enhancement. For impacts of land-based greenhouse gas removal technologies on biodiversity, some (e.g. soil carbon sequestration) could be neutral or positive, others (e.g. bioenergy with carbon capture and storage) are likely to lead to conflicts, while still others (e.g. afforestation/reforestation) are context-specific, when applied at scales necessary for meaningful greenhouse gas removal. Additional effort to meet the 1.5°C target presents some risks, particularly if inappropriately managed, but it also presents opportunities. This article is part of the theme issue `The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.

  10. Furostanol and Spirostanol Saponins from Tribulus terrestris

    Directory of Open Access Journals (Sweden)

    Zhen-Fang Wang

    2016-03-01

    Full Text Available Twelve new steroidal saponins, including eleven furostanol saponins, terrestrinin J–T (1–11, and one spirostanol saponin, terrestrinin U (12, together with seven known steroidal saponins 13–19 were isolated from T. terrestris. The structures of the new compounds were established on the basis of spectroscopic data, including 1D and 2D NMR and HRESIMS, and comparisons with published data.

  11. Impact of Oil on Bacterial Community Structure in Bioturbated Sediments

    Science.gov (United States)

    Stauffert, Magalie; Cravo-Laureau, Cristiana; Jézéquel, Ronan; Barantal, Sandra; Cuny, Philippe; Gilbert, Franck; Cagnon, Christine; Militon, Cécile; Amouroux, David; Mahdaoui, Fatima; Bouyssiere, Brice; Stora, Georges; Merlin, François-Xavier; Duran, Robert

    2013-01-01

    Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions – with tidal cycles and natural seawater – was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g−1 wet sediment), the common burrowing organism Hediste (Nereis) diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled) showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition) revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by

  12. Impact of oil on bacterial community structure in bioturbated sediments.

    Directory of Open Access Journals (Sweden)

    Magalie Stauffert

    Full Text Available Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions--with tidal cycles and natural seawater--was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g⁻¹ wet sediment, the common burrowing organism Hediste (Nereis diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by

  13. China's Coal Methane: Actors, Structures, Strategies and their Global Impacts

    International Nuclear Information System (INIS)

    Chen, Ke; Charnoz, Olivier

    2012-12-01

    The need for China to alleviate its energy shortage, reduce its dependence on foreign sources and mitigate its climate impact is driving a dire quest for alternative fuels. Coal Mine Methane (CMM), in this context, holds significant potential. While the 11. Five-Year Plan aimed to capture and use 10 billion m"3 per year of CMM by 2010, the country achieved less than a quarter of this. This paper enquires into this puzzling outcome, which bears consequences for the world at large. China is indeed responsible for more than 40% of the world's total un-captured CMM emissions - which act as a greenhouse gas 21 times more potent than CO_2, and whose role in global warming is often underestimated, especially in short- and medium-term climate strategies. While the Chinese central government may have incentive to work towards promoting CMM, the benefits of such policies at the sub-national level are far from self-evident. National CMM policies can have significant economic and social costs at the local level, and thus their implementation can be jeopardized. Implementation of such policies is inherently ambiguous, conflicting, and as such, political. Current research on the Chinese CMM industry has largely focused on its techno-economic aspects, with little if any politico-institutional analyses. As for policy research on the larger Chinese energy sector, this seems sturdily to embody a top-down view: it mostly ends up blaming the country's decentralized governance structure and lack of a stringent implementation chain. Such top-down approaches do not help uncover 'the sinews of war': the range of less formal mechanisms, negotiations and agreements among the local actors, without which implementation does not in fact occur at the sub-national level. Nor do top-down research approaches facilitate inquiry into the way local stakeholders re-frame the meaning, content and impact of CMM policies. More generally, the top-down approaches fail to consider the significance of

  14. The terrestrial record of Late Heavy Bombardment

    Science.gov (United States)

    Lowe, Donald R.; Byerly, Gary R.

    2018-04-01

    Until recently, the known impact record of the early Solar System lay exclusively on the surfaces of the Moon, Mars, and other bodies where it has not been erased by later weathering, erosion, impact gardening, and/or tectonism. Study of the cratered surfaces of these bodies led to the concept of the Late Heavy Bombardment (LHB), an interval from about 4.1 to 3.8 billion years ago (Ga) during which the surfaces of the planets and moons in the inner Solar System were subject to unusually high rates of bombardment followed by a decline to present low impact rates by about 3.5 Ga. Over the past 30 years, however, it has become apparent that there is a terrestrial record of large impacts from at least 3.47 to 3.22 Ga and from 2.63 to 2.49 Ga. The present paper explores the earlier of these impact records, providing details about the nature of the 8 known ejecta layers that constitute the evidence for large terrestrial impacts during the earlier of these intervals, the inferred size of the impactors, and the potential effects of these impacts on crustal development and life. The existence of this record implies that LHB did not end abruptly at 3.8-3.7 Ga but rather that high impact rates, either continuous or as impact clusters, persisted until at least the close of the Archean at 2.5 Ga. It implies that the shift from external, impact-related controls on the long-term development of the surface system on the Earth to more internal, geodynamic controls may have occurred much later in geologic history than has been supposed previously.

  15. Terrestrial ecosystems in a changing world

    Energy Technology Data Exchange (ETDEWEB)

    Canadell, J.G. [CSIRO Marine and Atmospheric Research, Canberra, ACT (Australia). Global Carbon Project; Pataki, D.E. [California Univ., Irvine, CA (United States). Dept. of Earth System Science]|[California Univ., Irvine, CA (United States). Dept. of Ecology and Evolutionary Biology; Pitelka, L.F. (eds.) [Maryland Univ., Frostburg, MD (United States). Appalachian Lab.

    2007-07-01

    Over 100 authors present 25 contributions on the impacts of global change on terrestrial ecosystems including: * key processes of the earth system such as the CO2 fertilization effect, shifts in disturbances and biome distribution, the saturation of the terrestrial carbon sink, and changes in functional biodiversity, * ecosystem services such the production of wheat, pest control, and carbon storage in croplands, and * sensitive regions in the world threaten by rapid changes in climate and land use such as high latitudes ecosystems, tropical forest in Southeast Asia, and ecosystems dominated by Monsoon climate. The book also explores new research developments on spatial thresholds and nonlinearities, the key role of urban development in global biogeochemical processes, and the integration of natural and social sciences to address complex problems of the human-environment system. (orig.)

  16. Effect factors for terrestrial acidification in Brazil

    DEFF Research Database (Denmark)

    Crespo Mendes, Natalia; Laurent, Alexis; Hauschild, Michael Zwicky

    conditions, which is an essential approach considering countries like Brazil, with high biodiversity. Previous studies have assessed the impacts of terrestrial acidification from the estimations of the potential losses of vascular plants species richness as a result of exposure to acidifying substances...... for 13 biomes, with 2409 species addressed for whole world. In this context this work aims to provide spatially-differentiated effect factors (EF) for terrestrial acidification in Brazil and support the development of spatially-differentiated characterization factors for Brazil. In order to maintain...... in Brazil, represented by 33167 species, indicating that this is a comprehensive study. Maps of soil pH in Brazil were extracted at 1-km resolution and pH values were extracted for the depth range of 0-30cm. For each ecoregion, species richness was plotted against soil pH and the exposure-response curves...

  17. Application of Terrestrial Environments in Orion Assessments

    Science.gov (United States)

    Barbre, Robert E.

    2016-01-01

    This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-earth orbit and is currently undergoing a series of tests including Exploration Test Flight (EFT) - 1. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

  18. Spiral arms, comets and terrestrial catastrophism

    International Nuclear Information System (INIS)

    Clube, S.V.M.; Napier, W.M.

    1982-01-01

    A review is presented of an hypothesis of terrestrial catastrophism in which comets grow in molecular clouds and are captured by the Sun as it passes through the spiral arms of the Galaxy. Assuming that comets are a major supplier of the Earth-crossing (Appollo) asteroid population, the latter fluctuates correspondingly and leads to episodes of terrestrial bombardment. Changes in the rotational momentum of core and mantle, generated by impacts, lead to episodes of magnetic field reversal and tectonic activity, while surface phenomena lead to ice-ages and mass extinctions. An episodic geophysical history with an interstellar connection is thus implied. If comets in spiral arms are necessary intermediaries in the process of star formation, the theory also has implications relating to early solar system history and galactic chemistry. These aspects are briefly discussed with special reference to the nature of spiral arms. (author)

  19. Structural identification of short/middle span bridges by rapid impact testing: theory and verification

    International Nuclear Information System (INIS)

    Zhang, Jian; Wu, Z S; Zhang, Q Q; Guo, S L; Xu, D W

    2015-01-01

    A structural strain flexibility identification method by processing the multiple-reference impact testing data is proposed. First, a kind of novel long-gauge fiber optic sensor is developed for structural macro-strain monitoring. Second, the multiple-reference impact testing technology is employed, during which both the impacting force and structural strain responses are measured. The impact testing technology has unique merit because it is able to extract exact structural frequency response functions (FRFs), while other test methods, for instance ambient tests, can only output the FRFs with scaled magnitudes. Most importantly, the originality of the article is that a method of identifying the structural strain flexibility characteristic from the impact test data has been proposed, which is useful for structural static strain prediction and capacity evaluation. Examples of a six meter simple supported beam and a multiple-span continuous beam bridge have successfully verified the effectiveness of the proposed method. (paper)

  20. Structural identification of short/middle span bridges by rapid impact testing: theory and verification

    Science.gov (United States)

    Zhang, Jian; Zhang, Q. Q.; Guo, S. L.; Xu, D. W.; Wu, Z. S.

    2015-06-01

    A structural strain flexibility identification method by processing the multiple-reference impact testing data is proposed. First, a kind of novel long-gauge fiber optic sensor is developed for structural macro-strain monitoring. Second, the multiple-reference impact testing technology is employed, during which both the impacting force and structural strain responses are measured. The impact testing technology has unique merit because it is able to extract exact structural frequency response functions (FRFs), while other test methods, for instance ambient tests, can only output the FRFs with scaled magnitudes. Most importantly, the originality of the article is that a method of identifying the structural strain flexibility characteristic from the impact test data has been proposed, which is useful for structural static strain prediction and capacity evaluation. Examples of a six meter simple supported beam and a multiple-span continuous beam bridge have successfully verified the effectiveness of the proposed method.

  1. Tidally Heated Terrestrial Exoplanets

    Science.gov (United States)

    Henning, Wade Garrett

    This work models the surface and internal temperatures for hypothetical terrestrial planets in situations involving extreme tidal heating. The feasibility of such planets is evaluated in terms of the orbital perturbations that may give rise to them, their required proximity to a hoststar, and the potential for the input tidal heating to cause significant partial melting of the mantle. Trapping terrestrial planets into 2:1 resonances with migrating Hot Jupiters is considered as a reasonable way for Earth-like worlds to both maintain high eccentricities and to move to short enough orbital periods (1-20 days) for extreme tidal heating to occur. Secular resonance and secular orbital perturbations may support moderate tidal heating at a low equilibrium eccentricity. At orbital periods below 10-30 days, with eccentricities from 0.01 to 0.1, tidal heat may greatly exceed radiogenic heat production. It is unlikely to exceed insolation, except when orbiting very low luminosity hosts, and thus will have limited surface temperature expression. Observations of such bodies many not be able to detect tidal surface enhancements given a few percent uncertainty in albedo, except on the nightside of spin synchronous airless objects. Otherwise detection may occur via spectral detection of hotspots or high volcanic gas concentrations including sulfur dioxide and hydrogen sulfide. The most extreme cases may be able to produce magma oceans, or magma slush mantles with up to 40-60% melt fractions. Tides may alter the habitable zones for smaller red dwarf stars, but are generally detrimental. Multiple viscoelastic models, including the Maxwell, Voigt-Kelvin, Standard Anelastic Solid, and Burgers rheologies are explored and applied to objects such as Io and the super-Earth planet GJ 876d. The complex valued Love number for the Burgers rheology is derived and found to be a useful improvement when modeling the low temperature behavior of tidal bodies, particularly during low eccentricity

  2. Impact of climate variability on terrestrial environment in Western Europe between 45 and 9 kyr cal. BP: vegetation dynamics recorded by the Bergsee Lake (Black Forest, Germany).

    Science.gov (United States)

    Duprat-Oualid, Fanny; Begeot, Carole; Rius, Damien; Millet, Laurent; Magny, Michel

    2016-04-01

    changes at millennial/pluri-millennial scale. The well-known afforestation of the Late-Glacial interstadial and the Holocene (with pine and hazel-dominated forests respectively) are recorded. Our results also reveal a three-phase sequence in the Last-Glacial. The persistence of very cold conditions between 24 and 30 kyr cal. BP favored a drastic steppe grassland. In contrast, trees proportion increased during the two other periods (14.7-24 and 30-45 kyr cal. BP) in correlation with a relative favorable climate. Second, the respons of vegetation to centennial scale climatic events is characterized by the successive rapid establishment of two different landscapes. GS are dominated by steppic taxa (Artemisia, Helianthemum), whereas more or less complete ecological successions Juniperus-Betula-Pinus seem to occur for most GIs when edaphic conditions became more favorable. Therefore, we suggest a global forcing defined by the strong impact of the climate variability on vegetation changes. We also propose the contribution of local characteristics (latitude, topography) which favored flora migration and long distance pollen inputs from refuge areas. Heiri O., Koinig K.A., Spötl C., Barrett S, Brauer A., Drescher-Schneider R., Gaar D., Ivy-Ochs S., Kerschner H., Luetscher M., Moran A., Nicolussi K., Preusser F., Schmidt R., Schoeneich P., Schwörer C., Sprafke T., Terhorst B., Tinner W. -2014- "Palaeoclimate records 60-8 ka in the Austrian and Swiss Alps and their forelands", Quaternary Science Review, 106 : 186-205.

  3. Sampling supraglacial debris thickness using terrestrial photogrammetry

    Science.gov (United States)

    Nicholson, Lindsey; Mertes, Jordan

    2017-04-01

    The melt rate of debris-covered ice differs to that of clean ice primarily as a function of debris thickness. The spatial distribution of supraglacial debris thickness must therefore be known in order to understand how it is likely to impact glacier behaviour, and meltwater contribution to local hydrological resources and global sea level rise. However, practical means of determining debris cover thickness remain elusive. In this study we explore the utility of terrestrial photogrammetry to produce high resolution, scaled and texturized digital terrain models of debris cover exposures above ice cliffs as a means of quantifying and characterizing debris thickness. Two Nikon D5000 DSLRs with Tamron 100mm lenses were used to photograph a sample area of the Ngozumpa glacier in the Khumbu Himal of Nepal in April 2016. A Structure from Motion workflow using Agisoft Photoscan software was used to generate a surface models with <10cm resolution. A Trimble Geo7X differential GPS with Zephyr antenna, along with a local base station, was used to precisely measure marked ground control points to scale the photogrammetric surface model. Measurements of debris thickness along the exposed cliffline were made from this scaled model, assuming that the ice surface at the debris-ice boundary is horizontal, and these data are compared to 50 manual point measurements along the same clifftops. We conclude that sufficiently high resolution photogrammetry, with precise scaling information, provides a useful means to determine debris thickness at clifftop exposures. The resolution of the possible measurements depends on image resolution, the accuracy of the ground control points and the computational capacity to generate centimetre scale surface models. Application of such techniques to sufficiently high resolution imagery from UAV-borne cameras may offer a powerful means of determining debris thickness distribution patterns over debris covered glacier termini.

  4. Ecological transfer mechanisms - Terrestrial

    International Nuclear Information System (INIS)

    Martin, W.E.; Raines, Gilbert E.; Bloom, S.G.; Levin, A.A.

    1969-01-01

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  5. Solar-terrestrial physics

    International Nuclear Information System (INIS)

    Patel, V.L.

    1977-01-01

    The Glossary is designed to be a technical dictionary that will provide solar workers of various specialties, students, other astronomers and theoreticians with concise information on the nature and the properties of phenomena of solar and solar-terrestrial physics. Each term, or group of related terms, is given a concise phenomenological and quantitative description, including the relationship to other phenomena and an interpretation in terms of physical processes. The references are intended to lead the non-specialist reader into the literature. This section deals with: geomagnetic field; coordinate systems; geomagnetic indices; Dst index; auroral electrojet index AE; daily, 27-day and semi-annual variations of geomagnetic field; micropulsation; geomagnetic storms; storm sudden commencement (SSC) or sudden commencement (SC); initial phase; ring current; sudden impulses; ionosphere; D region; polar cap absorption; sudden ionospheric disturbance; E region; sporadic E; equatorial electrojet; solar flare effect; F 1 and F 2 regions; spread F; travelling ionospheric disturbances; magnetosphere; magnetospheric coordinate systems; plasmasphere; magnetosheath; magnetospheric tail; substorm; radiation belts or Van Allen belts; whistlers; VLF emissions; aurora; auroral forms; auroral oval and auroral zones; auroral intensity; stable auroral red arcs; pulsing aurora; polar glow aurora; and airglow. (B.R.H.)

  6. Ecological transfer mechanisms - Terrestrial

    Energy Technology Data Exchange (ETDEWEB)

    Martin, W E; Raines, Gilbert E; Bloom, S G; Levin, A A [Battelle Memorial Institute, CoIumbus, OH (United States)

    1969-07-01

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  7. Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth; Markussen, Thor N; Stibal, Marek

    2016-01-01

    of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation......Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact...... and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity...

  8. Taiwan's industrial heavy metal pollution threatens terrestrial biota

    International Nuclear Information System (INIS)

    Hsu, M.J.; Selvaraj, K.; Agoramoorthy, G.

    2006-01-01

    The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan

  9. Aquatic and Terrestrial Environment 2004

    DEFF Research Database (Denmark)

    Andersen, J. M.; Boutrup, S.; Bijl, L. van der

    This report presents the 2004 results of the Danish National Monitoring and Assess-ment Programme for the Aquatic and Terrestrial Environments (NOVANA). 2004 was the first year in which terrestrial nature was included in the monitoring pro-gramme. The report reviews the state of the groundwater......, watercourses, lakes and marine waters and the pressures upon them and reviews the monitoring of terrestrial natural habitats and selected plants and animals. The report is based on the annual reports prepared for each subprogramme by the Topic Centres. The latter reports are mainly based on data collected...

  10. Design Manual for Impact Damage Tolerant Aircraft Structure. Addendum

    Science.gov (United States)

    1988-03-01

    Effective Flaw Size 20 22 Effective Flaws for Cubical Fragments Impacting Graphite/Epoxy Laminates 21 23 Effective Flaws for Aligned and Tumbled Armour ... armour -piercing projectiles impact, penetrate, and traverse a fuel tank and generate intensive pressure waves that act on the fuel tank. Since...eg. aerodynamic smoothnessflutter, etc.) and the repai concept (eag boiled repar external bonded pateh. flush scar bonded patch, etc., and (3) dhe

  11. Structural capacity assessment of a generic pre-stressed concrete containment structure under aircraft impact

    International Nuclear Information System (INIS)

    Iliev, Alexander

    2013-01-01

    The studied containment expressed adequate capacity to resist impact loads in the upper range of the studied diapason. The aircraft impact capacity of the containment for impact in the upper part of the cylindrical shell is about 25‐30% higher than the capacity for impact in the middle part of the cylindrical shell. The obtained fragility curves reefed to MoA can be then used for various additional calculations in the safety assessment of nuclear facilities under aircraft impact

  12. Steroidal saponins from Tribulus terrestris.

    Science.gov (United States)

    Kang, Li-Ping; Wu, Ke-Lei; Yu, He-Shui; Pang, Xu; Liu, Jie; Han, Li-Feng; Zhang, Jie; Zhao, Yang; Xiong, Cheng-Qi; Song, Xin-Bo; Liu, Chao; Cong, Yu-Wen; Ma, Bai-Ping

    2014-11-01

    Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-2α,3β,22α,26-tetrol-12-one (terrestrinin C), 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin D), 26-O-β-d-glucopyranosyl-(25S)-furost-4-en-22α,26-diol-3,6,12-trione (terrestrinin E), 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-3β,22α,26-triol-12-one (terrestrinin F), 26-O-β-d-glucopyranosyl-(25R)-furost-4-en-12β,22α,26-triol-3-one (terrestrinin G), 26-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl-(25R)-furost-4-en-22α,26-diol-3,12-dione (terrestrinin H), and 24-O-β-d-glucopyranosyl-(25S)-5α-spirostan-3β,24β-diol-12-one-3-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. On Variability in Satellite Terrestrial Chlorophyll Fluorescence Measurements: Relationships with Phenology and Ecosystem-Atmosphere Carbon Exchange, Vegetation Structure, Clouds, and Sun-Satellite Geometry

    Science.gov (United States)

    Joiner, J.; Yoshida, Y.; Guanter, L.; Zhang, Y.; Vasilkov, A. P.; Schaefer, K. M.; Huemmrich, K. F.; Middleton, E.; Koehler, P.; Jung, M.; Tucker, C. J.; Lyapustin, A.; Wang, Y.; Frankenberg, C.; Berry, J. A.; Koster, R. D.; Reichle, R. H.; Lee, J. E.; Kawa, S. R.; Collatz, G. J.; Walker, G. K.; Van der Tol, C.

    2014-12-01

    Over the past several years, there have been several breakthroughs in our ability to detect the very small fluorescence emitted by chlorophyll in vegetation globally from space. There are now multiple instruments in space capable of measuring this signal at varying temporal and spatial resolutions. We will review the state-of-the-art with respect to these relatively new satellite measurements and ongoing studies that examine the relationships with photosynthesis. Now that we have a data record spanning more than seven years, we can examine variations due to seasonal carbon uptake, interannual variability, land-use changes, and water and temperature stress. In addition, we examine how clouds and satellite viewing geometry impact the signal. We compare and contrast these variations with those from popular vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), related to the potential photosynthesis as well as with measurements from flux tower gas exchange measurements and other model-based estimates of Global Primary Productivity (GPP). Vegetation fluorescence can be simulated in global vegetation models as well as with 1D canopy radiative transport models. We will describe how the satellite fluorescence data are being used to evaluate and potentially improve these models.

  14. Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America.

    Science.gov (United States)

    Mitchell, Jonathan S; Roopnarine, Peter D; Angielczyk, Kenneth D

    2012-11-13

    The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

  15. Culture, Structure and Leadership Impacts on Gender Inclusion in the Security Sector

    Science.gov (United States)

    2017-09-01

    Culture, structure and leadership impacts on gender inclusion in the security sector 1 DANIEL K. INOUYE ASIA PACIFIC CENTER FOR SECURITY...STUDIES OCCASIONAL PAPER, SEPTEMBER 2017 Culture, structure and leadership impacts on gender inclusion in the security sector Canyon DV Abstract...Depending on your perspective, the primary challenge to gender inclusion is either culture, structure or leadership . The good news is that they are all

  16. Environmental impact on morphological and anatomical structure of ...

    African Journals Online (AJOL)

    Morphological and anatomical structure of Tansy (Tanacetum vulgare L.) from two specific locations in one town, depending on environmental conditions, were carried out: anthropogenic Ada Huja (polluted zone) and non anthropogenic Topcider park (unpolluted). Study included the diferences in the structure of leaves, ...

  17. Analysis of NPP protection structure reliability under impact of a falling aircraft

    International Nuclear Information System (INIS)

    Shul'man, G.S.

    1996-01-01

    Methodology for evaluation of NPP protection structure reliability by impact of aircraft fall down is considered. The methodology is base on the probabilistic analysis of all potential events. The problem is solved in three stages: determination of loads on structural units, calculation of local reliability of protection structures by assigned loads and estimation of the structure reliability. The methodology proposed may be applied at the NPP design stage and by determination of reliability of already available structures

  18. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors.

    Science.gov (United States)

    Si, Liang; Baier, Horst

    2015-07-08

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with "orange peel" surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments.

  19. The behavior of osmium and other siderophile elements during impacts: Insights from the Ries impact structure and central European tektites

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Magna, T.; Žák, Karel; Skála, Roman; Jonášová, Šárka; Mizera, Jiří; Řanda, Zdeněk

    2017-01-01

    Roč. 210, 1 August (2017), s. 59-70 ISSN 0016-7037 R&D Projects: GA ČR GA13-22351S; GA MŠk LM2015056 Institutional support: RVO:67985831 ; RVO:61389005 Keywords : highly siderophile elements * meteoritic component * Osmium isotopes * Ries impact structure * tektite Subject RIV: DB - Geology ; Mineralogy; CB - Analytical Chemistry, Separation (UJF-V) OBOR OECD: Geology; Analytical chemistry (UJF-V) Impact factor: 4.609, year: 2016

  20. Towards reliable simulations of ballistic impact on concrete structures

    NARCIS (Netherlands)

    Khoe, Y.S.; Tyler Street, M.D.; Maravalalu Suresh,, R.S.; Weerheijm, J.

    2013-01-01

    Protection against weapon effects like ballistic impacts, fragmenting shells and explosions is the core business of the Explosions, Ballistics and Protection department of TNO (The Netherlands). Experimental and numerical research is performed to gain and maintain the knowledge to support the Dutch

  1. Impact of Seed Structure Modification on the Rate

    Czech Academy of Sciences Publication Activity Database

    Rochová, Kristina; Sovová, Helena; Sobolík, Václav; Allaf, K.

    2008-01-01

    Roč. 44, č. 2 (2008), s. 211-218 ISSN 0896-8446 R&D Projects: GA AV ČR(CZ) GA104/06/1174 Institutional research plan: CEZ:AV0Z40720504 Keywords : dic process * supercritical extraction * porosity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.428, year: 2008

  2. Droplet impact on superheated micro-structured surfaces

    NARCIS (Netherlands)

    Tran, Tuan; Staat, Erik-Jan; Susarrey Arce, A.; Foertsch, T.C.; van Houselt, Arie; Gardeniers, Johannes G.E.; Prosperetti, Andrea; Lohse, Detlef; Sun, Chao

    2013-01-01

    When a droplet impacts upon a surface heated above the liquid's boiling point, the droplet either comes into contact with the surface and boils immediately (contact boiling), or is supported by a developing vapor layer and bounces back (film boiling, or Leidenfrost state). We study the transition

  3. Methane emissions form terrestrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, P.; Dentener, F.; Grassi, G.; Leip, A.; Somogyi, Z.; Federici, S.; Seufert, G.; Raes, F. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

    2006-07-01

    In a recent issue of Nature Keppler et al. (2006) report the discovery that terrestrial plants emit CH4 under aerobic conditions. Until now it was thought that bacterial decomposition of plant material under anaerobic conditions, such as in wetlands and water flooded rice paddies, is the main process leading to emissions from terrestrial ecosystems. In a first attempt to upscale these measurements, the authors estimate that global total emissions may be 149 Tg CH4/yr (62-236 Tg CH4/yr), with the main contribution estimated from tropical forests and grasslands (107 Tg CH4/yr with a range of 46-169 Tg CH4/yr). If confirmed, this new source of emission would constitute a significant fraction of the total global methane sources (estimated 500-600 Tg CH4/yr for present day total natural and anthropogenic sources) and have important implications for the global CH4 budget. To accommodate it within the present budget some sources would need to be re-assessed downwards and/or some sinks re-assessed upwards. Furthermore, also considering that methane is a {approx}23 times more powerful greenhouse gas than CO2, the possible feedbacks of these hitherto unknown CH4 emissions on global warming and their impacts on greenhouse gases (GHG) mitigation strategies need to be carefully evaluated. The merit of the paper is without doubt related to the remarkable discovery of a new process of methane emissions active under aerobic conditions. However, we think that the applied approach of scaling up emissions from the leaf level to global totals by using only few measured data (mainly from herbaceous species) and the Net Primary Productivity of the main biomes is scientifically questionable and tends to overestimate considerably the global estimates, especially for forest biomes. Furthermore, some significant constraints on the upper limit of the global natural CH4 emissions arise from the pre-industrial CH4 budget. Pre-industrial atmospheric CH4 mixing ratios have been measured

  4. The Impact of Structural Competence towards Speaking Competence of the Fourth Semester Students of English Department

    Directory of Open Access Journals (Sweden)

    Muhammad Nafi Annury

    2013-11-01

    Full Text Available This paper tries to define any impact of structural competence towards speaking competence. In this research, the writer used descriptive co-relational method. It was used to describe whether there was an impact between two variables, i.e. structural competence (X as independent variable and speaking competence (Y as dependent variable. The subject of study was the fourth semester students of English department of Tarbiyah Faculty IAIN Walisongo Semarang. After the data had been analyzed, it was found that there was significant impact of structural competence especially in appropriateness. It helped students to arrange words into sentences that they utter.

  5. Largest terrestrial electromagnetic pulsar

    Czech Academy of Sciences Publication Activity Database

    Pardy, Miroslav

    2002-01-01

    Roč. 46, č. 6 (2002), s. 1155-1163 ISSN 0020-7748 R&D Projects: GA MŠk LN00A100 Institutional research plan: CEZ:AV0Z2043910 Keywords : source theory, spectral formula, synchrotron radiation Subject RIV: BE - Theoretical Physics Impact factor: 0.655, year: 2002

  6. Team Structure and Scientific Impact of "Big Science" Research

    DEFF Research Database (Denmark)

    Lauto, Giancarlo; Valentin, Finn; Jeppesen, Jacob

    This paper summarizes preliminary results from a project studying how the organizational and cognitive features of research carried out in a Large Scale Research Facility (LSRF) affect scientific impact. The study is based on exhaustive bibliometric mapping of the scientific publications...... of the Neutron Science Department of Oak Ridge National Laboratories in 2006-2009. Given the collaborative nature of research carried out at LSRFs, it is important to understand how its organization affects scientific impact. Diversity of teams along the institutional and cognitive dimensions affects both...... opportunities for combination of knowledge and coordination costs. The way specific collaborative configurations strike this trade-offs between these opportunities and costs have notable effects on research performance. The findings of the paper show that i.) scientists combining affiliations to both...

  7. Impact of aging and material structure on CANDU plant performance

    International Nuclear Information System (INIS)

    Nadeau, E.; Ballyk, J.; Ghalavand, N.

    2011-01-01

    In-service behaviour of pressure tubes is a key factor in the assessment of safety margins during plant operation. Pressure tube deformation (diametral expansion) affects fuel bundle dry out characteristics resulting in reduced margin to trip for some events. Pressure tube aging mechanisms also erode design margins on fuel channels or interfacing reactor components. The degradation mechanisms of interest are primarily deformation, loss of fracture resistance and hydrogen ingress. CANDU (CANada Deuterium Uranium, a registered trademark of the Atomic Energy of Canada Limited used under exclusive licence by Candu Energy Inc.) owners and operators need to maximize plant capacity factor and meet or exceed the reactor design life targets while maintaining safety margins. The degradation of pressure tube material and geometry are characterized through a program of inspection, material surveillance and assessment and need to be managed to optimize plant performance. Candu is improving pressure tubes installed in new build and life extension projects. Improvements include changes designed to reduce or mitigate the impact of pressure tube elongation and diametral expansion rates, improvement of pressure tube fracture properties, and reduction of the implications of hydrogen ingress. In addition, Candu provides an extensive array of engineering services designed to assess the condition of pressure tubes and address the impact of pressure tube degradation on safety margins and plant performance. These services include periodic and in-service inspection and material surveillance of pressure tubes and deterministic and probabilistic assessment of pressure tube fitness for service to applicable standards. Activities designed to mitigate the impact of pressure tube deformation on safety margins include steam generator cleaning, which improves trip margins, and trip design assessment to optimize reactor trip set points restoring safety and operating margins. This paper provides an

  8. Impact of aging and material structure on CANDU plant performance

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, E.; Ballyk, J.; Ghalavand, N. [Candu Energy Inc., Mississauga, Ontario (Canada)

    2011-07-01

    In-service behaviour of pressure tubes is a key factor in the assessment of safety margins during plant operation. Pressure tube deformation (diametral expansion) affects fuel bundle dry out characteristics resulting in reduced margin to trip for some events. Pressure tube aging mechanisms also erode design margins on fuel channels or interfacing reactor components. The degradation mechanisms of interest are primarily deformation, loss of fracture resistance and hydrogen ingress. CANDU (CANada Deuterium Uranium, a registered trademark of the Atomic Energy of Canada Limited used under exclusive licence by Candu Energy Inc.) owners and operators need to maximize plant capacity factor and meet or exceed the reactor design life targets while maintaining safety margins. The degradation of pressure tube material and geometry are characterized through a program of inspection, material surveillance and assessment and need to be managed to optimize plant performance. Candu is improving pressure tubes installed in new build and life extension projects. Improvements include changes designed to reduce or mitigate the impact of pressure tube elongation and diametral expansion rates, improvement of pressure tube fracture properties, and reduction of the implications of hydrogen ingress. In addition, Candu provides an extensive array of engineering services designed to assess the condition of pressure tubes and address the impact of pressure tube degradation on safety margins and plant performance. These services include periodic and in-service inspection and material surveillance of pressure tubes and deterministic and probabilistic assessment of pressure tube fitness for service to applicable standards. Activities designed to mitigate the impact of pressure tube deformation on safety margins include steam generator cleaning, which improves trip margins, and trip design assessment to optimize reactor trip set points restoring safety and operating margins. This paper provides an

  9. Distributive impacts of alternative tax structures. The case of Uruguay

    OpenAIRE

    Verónica Amarante; Marisa Bucheli; Cecilia Olivieri; Ivone Perazzo

    2011-01-01

    This article considers the distributional impact of different changes in Uruguayan tax system, using a static micro-simulation framework based on the combination of data from household and expenditure surveys. On the indirect taxes side, we consider two alternatives that imply the same reduction in tax revenue: a general reduction of 2 points in the VAT basic rate, and a selective reduction in the VAT rate applied to specific goods that make up a large share of consumption of low income popul...

  10. Modeling of fracture of protective concrete structures under impact loads

    Energy Technology Data Exchange (ETDEWEB)

    Radchenko, P. A., E-mail: radchenko@live.ru; Batuev, S. P.; Radchenko, A. V.; Plevkov, V. S. [Tomsk State University of Architecture and Building, Tomsk, 634003 (Russian Federation)

    2015-10-27

    This paper presents results of numerical simulation of interaction between a Boeing 747-400 aircraft and the protective shell of a nuclear power plant. The shell is presented as a complex multilayered cellular structure consisting of layers of concrete and fiber concrete bonded with steel trusses. Numerical simulation was performed three-dimensionally using the original algorithm and software taking into account algorithms for building grids of complex geometric objects and parallel computations. Dynamics of the stress-strain state and fracture of the structure were studied. Destruction is described using a two-stage model that allows taking into account anisotropy of elastic and strength properties of concrete and fiber concrete. It is shown that wave processes initiate destruction of the cellular shell structure; cells start to destruct in an unloading wave originating after the compression wave arrival at free cell surfaces.

  11. Modeling of fracture of protective concrete structures under impact loads

    Science.gov (United States)

    Radchenko, P. A.; Batuev, S. P.; Radchenko, A. V.; Plevkov, V. S.

    2015-10-01

    This paper presents results of numerical simulation of interaction between a Boeing 747-400 aircraft and the protective shell of a nuclear power plant. The shell is presented as a complex multilayered cellular structure consisting of layers of concrete and fiber concrete bonded with steel trusses. Numerical simulation was performed three-dimensionally using the original algorithm and software taking into account algorithms for building grids of complex geometric objects and parallel computations. Dynamics of the stress-strain state and fracture of the structure were studied. Destruction is described using a two-stage model that allows taking into account anisotropy of elastic and strength properties of concrete and fiber concrete. It is shown that wave processes initiate destruction of the cellular shell structure; cells start to destruct in an unloading wave originating after the compression wave arrival at free cell surfaces.

  12. National customer satisfaction indices: The impact of market structure

    DEFF Research Database (Denmark)

    Eskildsen, Jacob Kjær; Kristensen, Kai

    The popularity of customer satisfaction measurements has grown considerably over the last few years but we know very little about how the structure of the individual markets with respect to the transparency of products and services as well as consumer preferences affects customer satisfaction. Here...... a total of 14540 customers have evaluated their preferred supplier with respect to banking, property insurance, supermarkets and mobile telecom. The analysis shows that market structure has a profound effect on customer satisfaction measurements and that this effect differs from industry to industry....... The paper concludes with an evaluation of the implications of the findings in relation to the use of results from customer satisfaction studies....

  13. The Impact of Capital Structure on Stock Returns: International Evidence

    Directory of Open Access Journals (Sweden)

    Reza TAHMOORESPOUR

    2015-03-01

    Full Text Available This study examines the relationship between capital structure and stock returns of firms in the following eight countries in the Asia Pacific regionfor a period of 22 years from 1990 to 2012. The methodology is Panel Regression. The results indicate that the effect of capital structure depends on the nature of industry as well as market. In Australia, China, and Korea, return of companies in the Basic Material industry have negative relationship with debt to common equity. Long term debt to common equity positively affects the return of firms in Australia and Korea in the Basic Material industry.

  14. Achievements and opportunities from ESF Research Networking Programme: Natural molecular structures as drivers and tracers of terrestrial C fluxes, and COST Action 639: Greenhouse gas budget of soils under changing climate and land use

    Science.gov (United States)

    Boeckx, P.; Rasse, D.; Jandl, R.

    2009-04-01

    One of the activities of the European Science Foundation (ESF, www.esf.org) is developing European scale Research Networking Programmes (RNPs). RNPs lay the foundation for nationally funded research groups to address major scientific and research infrastructure issues, in order to advance the frontiers of existing science. MOLTER (www.esf.org/molter or www.molter.no) is such an RNP. MOLTER stands for "Natural molecular structures as drivers and tracers of terrestrial C fluxes" aims at stimulating the use of isotopic and organic chemistry to study carbon stabilization and biogeochemistry in terrestrial ecosystems and soils in particular. The understanding of the formation, stabilization and decomposition of complex organic compounds in the environment is currently being revolutionized by advanced techniques in identification, quantification, and origin tracing of functional groups and individual molecules. MOLTER focuses on five major research themes: - Molecular composition and turnover time of soil organic matter; - Plant molecular structures as drivers of C stabilisation in soils; - Fire transformations of plant and soil molecular structures - Molecular markers in soils; - Dissolved organic molecules in soils: origin, functionality and transport. These research themes are covered via the following activities: - Organisation of international conferences; - Organisation of specific topical workshops; - Organisation of summer schools for PhD students; - Short- and long-term exchange grants for scientists. MOLTER is supported by research funding or performing agencies from Austria, Belgium, France, Germany, the Netherlands, Norway, Romania, Spain, Sweden, Switzerland and the United Kingdom. The ESF is also the implementing agency of COST (European Cooperation in Science and Technology, www.cost.esf.org), one of the longest-running European instruments supporting cooperation among scientists and researchers across Europe. COST Action 639 "Greenhouse gas budget of

  15. Impact of spatial dimension on structural ordering in metallic glass.

    Science.gov (United States)

    Hu, Yuan-Chao; Tanaka, Hajime; Wang, Wei-Hua

    2017-08-01

    Metallic glasses (MGs) have so far attracted considerable attention for their applications as bulk materials. However, new physics and applications often emerge by dimensional reduction from three dimensions (3D) to two dimensions (2D). Here, we study, by molecular dynamics simulations, how the liquid-to-glass transition of a binary Cu_{50}Zr_{50} MG is affected by spatial dimensionality. We find clear evidence that crystal-like structural ordering controls both dynamic heterogeneity and slow dynamics, and thus plays a crucial role in the formation of the 2DMG. Although the 2DMG reproduces the dynamical behaviors of its 3D counterpart by considering Mermin-Wagner-type fluctuations specific to 2D, this atomic-scale structural mechanism is essentially different from that for the 3DMG in which icosahedral clusters incompatible with crystallographic symmetry play a key role in glassy behaviors. Our finding provides a structural mechanism for the formation of 2DMGs, which cannot be inferred from the knowledge of 3DMGs. The results suggest a structural basis for the glass transition in 2DMG and provide possible explanations for some previous experimental observations in ultrathin film MGs.

  16. Impacts of chemical gradients on microbial community structure

    DEFF Research Database (Denmark)

    Chen, Jianwei; Hanke, Anna; Tegetmeyer, Halina E

    2017-01-01

    Succession of redox processes is sometimes assumed to define a basic microbial community structure for ecosystems with oxygen gradients. In this paradigm, aerobic respiration, denitrification, fermentation and sulfate reduction proceed in a thermodynamically determined order, known as the 'redox ...... Journal advance online publication, 17 January 2017; doi:10.1038/ismej.2016.175....

  17. The Impact Of Family Structure On Psychosocial Adjustment Of ...

    African Journals Online (AJOL)

    This paper x-ray the psychosocial adjustment of adolescences based on their families structure, hence families were further revealed to include intact family, divorced family, separated family, psychological and none psychological broken homes, as it influence adolescence generally. Under the definition of terms ...

  18. Genetic modification and its impact on industry structure and performance

    NARCIS (Netherlands)

    Vlaar, P.W.L.; van Beek, P.; Visser, R.G.F.

    2007-01-01

    Genetic modification has led to fierce debates around the world. Nevertheless, scientific evidence for its potential effects on the structure and performance of industries has hitherto remained rather meagre. In this article, we take some preliminary steps towards closing this gap by exploring the

  19. Modelling functional and structural impact of non-synonymous ...

    African Journals Online (AJOL)

    ... that could affect protein function and structure. Further wet-lab confirmatory analysis in a pathological association study involving a larger population of goats is required at the DQA1 locus. This would lay a sound foundation for breeding disease-resistant individuals in the future. Keywords: Goats, in silico, mutants, protein, ...

  20. Impact of Information Technology Governance Structures on Strategic Alignment

    Science.gov (United States)

    Gordon, Fitzroy R.

    2013-01-01

    This dissertation is a study of the relationship between Information Technology (IT) strategic alignment and IT governance structure within the organization. This dissertation replicates Asante (2010) among a different population where the prior results continue to hold, the non-experimental approach explored two research questions but include two…

  1. Impact of structural reforms on planning systems and policies

    DEFF Research Database (Denmark)

    Galland, Daniel; Enemark, Stig

    2013-01-01

    spatial development processes. The reasoning behind this argument stems from the case of Denmark, where a structural reform that changed the country’s geographies of inter-governmental arrangements significantly transformed the configuration and functioning of the national spatial planning system. Once...... concerning how the scope of Danish spatial planning has been reoriented over time in light of three interrelated strands of understanding....

  2. (Mohar) impact structure, Shivpuri district., Madhya Pradesh, India

    Indian Academy of Sciences (India)

    8

    The melt breccia, occurring as sparse isolated outcrops around the structure, is an extremely .... The clast, under the naked eye (Fig.7a; sample no. ..... Mohar Cauldron, Shivpuri district, M.P. Unpublished Annual Report of Field Season 2005-2006 ... induced shock metamorphism in the basement granitoids and rhyolitic melt ...

  3. Impact of culture on autobiographical life structure in depression.

    Science.gov (United States)

    Jobson, Laura; Miskon, Nazleen; Dalgleish, Tim; Hitchcock, Caitlin; Hill, Emma; Golden, Ann-Marie; Zulkefly, Nor Sheereen; Mukhtar, Firdaus

    2018-03-23

    Distortions in autobiographical memory have been implicated in major depressive disorder (MDD). Those with MDD demonstrate a 'depressogenic' autobiographical life structure. Research has not examined how culture influences this process. We investigated whether Malay individuals (members of an interdependent culture) with MDD demonstrated a 'depressogenic' autobiographical life structure similar to that of British individuals (members of an independent culture) with MDD. A 2 (Culture; Malay, British) × 2 (Mood; depressed, control) cross-sectional design using a card sort task and self-report measures was used. Malay individuals with MDD or no history of MDD completed the life-structure card-sorting task, which provided a novel method for investigating organizational structure of the life narrative. These data were compared to previously collected data in which British individuals with MDD or without MDD had completed the same task within the same experimental protocol. Pan-culturally those with MDD had greater negativity (i.e., used more negative attributes), negative redundancy (i.e., used the same negative attributes repeatedly across life chapters) and negative emodiversity (i.e., had greater variety and relative abundance of negative attributes), and reduced positive redundancy (i.e., used the same positive attributes repeatedly across chapters) in their structuring relative to controls. While the British MDD group had greater compartmentalization (i.e., the negative and positive attributes were clustered separately across different chapters) than British controls, the Malay MDD group had lower levels of compartmentalization than Malay controls. The findings suggest culture may shape aspects of the autobiographical life structure in MDD. The majority of the literature investigating depression pertains to individuals from European Western cultures, despite recognition that depression ranks as one of the most debilitating diseases worldwide. This raises

  4. A compilation of structural property data for computer impact calculation (5/5)

    International Nuclear Information System (INIS)

    Ikushima, Takeshi

    1988-10-01

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 5 involve structural property data of wood. (author)

  5. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2011-01-01

    Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of

  6. Reinforced concrete structures under impact and impulsive loading: recent development, problems and trends

    International Nuclear Information System (INIS)

    Plauk, G.; Herter, J.

    1984-01-01

    Nuclear plant facilities and other reinforced concrete structures have to be regarded as to their safety in design and construction with respect to impact and impulsive loading in order to avoid serious damage to mankind and environment. The paper gives a survey on theoretical and experimental developments currently in progress, in particular regarding airplane crash. Some new results arising out of several research programs relevant to particular problems of impact loading have been reviewed and are presented. Experimental investigation for determination of material properties of plain concrete, reinforcing steel as well as steel-concrete bond under high strain-rates are treated in this paper including theoretical approaches for the respective material laws. An outline of soft missile impact tests performed on structural members, e.g. beams and plates, to determine the load deformation or fracture behaviour is given. Furthermore, numerical models and calculations to analyse structural components and structures under impact loading were discussed. (Author) [pt

  7. Local damage to reinforced concrete structures caused by impact of aircraft engine missiles. Pt. 1

    International Nuclear Information System (INIS)

    Sugano, T.; Tsubota, H.; Kasai, Y.; Koshika, N.; Ohnuma, H.; Von Riesemann, W.A.; Bickel, D.C.; Parks, M.B.

    1993-01-01

    Structural damage induced by an aircraft crashing into a reinforced concrete structure includes local damage caused by the deformable engines, and global damage caused by the entire aircraft. Local damage to the target may consist of spalling of concrete from its front face together with missile penetration into it, scabbing of concrete from its rear face, and perforation of missile through it. Until now, local damage to concrete structures has been mainly evaluated by rigid missile impact tests. Past research work regarding local damage caused by impact of deformable missiles has been limited. This paper presents the results of a series of impact tests of small-, intermediate-, and full-scale engine models into reinforced concrete panels. The purpose of the tests was to determine the local damage to a reinforced concrete structure caused by the impact of a deformable aircraft engine. (orig.)

  8. Impact of maintenance dredging on macrobenthic community structure of a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rehitha, T.V.; Ullas, N.; Vineetha, G.; Benny, P.Y.; Madhu, N.V.; Revichandran, C.

    This paper demonstrates the impact of maintenance dredging activities on the macrobenthic community structure of a tropical monsoonal estuary (Cochin estuary), located in the southwest coast of India for three consecutive years. The results...

  9. Modeling the Effect of Fluid-Structure Interaction on the Impact Dynamics of Pressurized Tank Cars

    Science.gov (United States)

    2009-11-13

    This paper presents a computational framework that : analyzes the effect of fluid-structure interaction (FSI) on the : impact dynamics of pressurized commodity tank cars using the : nonlinear dynamic finite element code ABAQUS/Explicit. : There exist...

  10. Vulnerability Assessment for a Complex Structure Using Vibration Response Induced by Impact Load

    International Nuclear Information System (INIS)

    Park, Jeongwon; Park, Junhong; Koo, Man Hoi

    2014-01-01

    This work presents a vulnerability assessment procedure for a complex structure using vibration characteristics. The structural behavior of a three-dimensional framed structure subjected to impact forces was predicted using the spectral element method. The Timoshenko beam function was applied to simulate the impact wave propagations induced by a high-velocity projectile at relatively high frequencies. The interactions at the joints were analyzed for both flexural and longitudinal wave propagations. Simulations of the impact energy transfer through the entire structure were performed using the transient displacement and acceleration responses obtained from the frequency analysis. The kill probabilities of the crucial components for an operating system were calculated as a function of the predicted acceleration amplitudes according to the acceptable vibration levels. Following the proposed vulnerability assessment procedure, the vulnerable positions of a three-dimensional combat vehicle with high possibilities of damage generation of components by impact loading were identified from the estimated vibration responses

  11. Approximating spectral impact of structural perturbations in large networks

    CERN Document Server

    Milanese, A; Nishikawa, Takashi; Sun, Jie

    2010-01-01

    Determining the effect of structural perturbations on the eigenvalue spectra of networks is an important problem because the spectra characterize not only their topological structures, but also their dynamical behavior, such as synchronization and cascading processes on networks. Here we develop a theory for estimating the change of the largest eigenvalue of the adjacency matrix or the extreme eigenvalues of the graph Laplacian when small but arbitrary set of links are added or removed from the network. We demonstrate the effectiveness of our approximation schemes using both real and artificial networks, showing in particular that we can accurately obtain the spectral ranking of small subgraphs. We also propose a local iterative scheme which computes the relative ranking of a subgraph using only the connectivity information of its neighbors within a few links. Our results may not only contribute to our theoretical understanding of dynamical processes on networks, but also lead to practical applications in ran...

  12. The positive impact of structured teaching in the operating room.

    Science.gov (United States)

    Leung, Yee; Salfinger, Stuart; Mercer, Annette

    2015-12-01

    A survey of obstetric and gynaecology trainees in Australia found the trainee's opinion of the consultants' teaching ability for laparoscopic procedures and procedures dealing with complications as 'poor' in 21.2% and 23.4% of responses, respectively (Aust NZ J Obstet Gynaecol 2009; 49: 84). Surgical caseload per trainee is falling for a variety of reasons. Strategies need to be adopted to enhance the surgical learning experience of trainees in the operating room. We describe the use of a structured encounter template to facilitate the teaching of surgery in the operating room and report the response of the trainees to this intervention. Trainees attached to a gynaecologic surgery unit all underwent surgical training using a set format based on the surgical encounter template, including briefing, goal setting and intra-operative teaching aims as well as debriefing. Data on the trainees' experience and perception of their learning experience were then collected and analysed as quantitative and qualitative data sets. The trainees reported satisfaction with the use of a structured encounter template to facilitate the surgical teaching in the operating room. Some trainees had not received such clarity of feedback or the opportunity to complete a procedure independently prior to using the structured encounter template. A structured surgical encounter template based on andragogy principles to focus consultant teaching in the operating room is highly acceptable to obstetric and gynaecology trainees in Australia. Allowing the trainee the opportunity to set objectives and receive feedback empowers the trainee and enhances their educational experience. © 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  13. Impacts of Power Structure on Sustainable Supply Chain Management

    OpenAIRE

    Zhi Li; Yangyang Xu; Fumin Deng; Xuedong Liang

    2017-01-01

    The present paper examines the manufacturer’s operational decisions, e.g., wholesale price and product sustainability level, the retailer’s operational decision, e.g., retail margin, and supply chain efficiency under three supply chain power structures: manufacturer Stackelberg, Nash and retailer Stackelberg. As a benchmark, we first obtain the equlibrium price and product sustainability level in a vertically integrated supply chain. Our analysis provides some interesting findings in a decent...

  14. A New Furostanol Glycoside from Tribulus terrestris

    Directory of Open Access Journals (Sweden)

    Tonghua Liu

    2010-01-01

    Full Text Available Besides two known glycosides, a new furostanol glycoside was isolated from the Fruits of Tribulus terrestris L. The structure of the new furostanol glycoside was established as 26-O-β-D-glucopyranosyl-(25S-5α-furostane-20(22-en-12-one-3β, 26-diol-3-O-α-L-rhamnopyranosyl-(1→2-[β-D-glucopyranosyl-(1→4]-β-D-galactopyranoside (1 on the basis of 1D and 2D-NMR techniques, including COSY, HMBC, and HMQC correlations.

  15. Two new furostanol saponins from Tribulus terrestris.

    Science.gov (United States)

    Xu, Ya-Juan; Xu, Tun-Hai; Zhou, Hai-Ou; Li, Bo; Xie, Sheng-Xu; Si, Yun-Shan; Liu, Yue; Liu, Tong-Hua; Xu, Dong-Ming

    2010-05-01

    Two new furostanol saponins were isolated from the fruits of Tribulus terrestris L. Their structures were established as 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furost-20(22)-en-3beta,26-diol-3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-glucopyranosyl-(1 --> 4)]-beta-D-galactopyranoside (1) and 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furost-20(22)-en-12-one-3beta,26-diol-3-O-beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside (2) on the basis of spectroscopic data as well as chemical evidence.

  16. A new furostanol glycoside from Tribulus terrestris.

    Science.gov (United States)

    Xu, Yajuan; Liu, Yonghong; Xu, Tunhai; Xie, Shengxu; Si, Yunshan; Liu, Yue; Zhou, Haiou; Liu, Tonghua; Xu, Dongming

    2010-01-27

    Besides two known glycosides, a new furostanol glycoside was isolated from the Fruits of Tribulus terrestris L. The structure of the new furostanol glycoside was established as 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furostane-20(22)-en-12-one-3beta, 26-diol-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-beta-D-galactopyranoside (1) on the basis of 1D and 2D-NMR techniques, including COSY, HMBC, and HMQC correlations.

  17. Structural and Functional Impacts of ER Coactivator Sequential Recruitment.

    Science.gov (United States)

    Yi, Ping; Wang, Zhao; Feng, Qin; Chou, Chao-Kai; Pintilie, Grigore D; Shen, Hong; Foulds, Charles E; Fan, Guizhen; Serysheva, Irina; Ludtke, Steven J; Schmid, Michael F; Hung, Mien-Chie; Chiu, Wah; O'Malley, Bert W

    2017-09-07

    Nuclear receptors recruit multiple coactivators sequentially to activate transcription. This "ordered" recruitment allows different coactivator activities to engage the nuclear receptor complex at different steps of transcription. Estrogen receptor (ER) recruits steroid receptor coactivator-3 (SRC-3) primary coactivator and secondary coactivators, p300/CBP and CARM1. CARM1 recruitment lags behind the binding of SRC-3 and p300 to ER. Combining cryo-electron microscopy (cryo-EM) structure analysis and biochemical approaches, we demonstrate that there is a close crosstalk between early- and late-recruited coactivators. The sequential recruitment of CARM1 not only adds a protein arginine methyltransferase activity to the ER-coactivator complex, it also alters the structural organization of the pre-existing ERE/ERα/SRC-3/p300 complex. It induces a p300 conformational change and significantly increases p300 HAT activity on histone H3K18 residues, which, in turn, promotes CARM1 methylation activity on H3R17 residues to enhance transcriptional activity. This study reveals a structural role for a coactivator sequential recruitment and biochemical process in ER-mediated transcription. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Conformational impact of structural modifications in 2-fluorocyclohexanone

    Directory of Open Access Journals (Sweden)

    Francisco A. Martins

    2017-08-01

    Full Text Available 2-Haloketones are building blocks that combine physical, chemical and biological features of materials and bioactive compounds, while organic fluorine plays a fundamental role in the design of performance organic molecules. Since these features are dependent on the three-dimensional chemical structure of a molecule, simple structural modifications can affect its conformational stability and, consequently, the corresponding physicochemical/biological property of interest. In this work, structural changes in 2-fluorocyclohexanone were theoretically studied with the aim at finding intramolecular interactions that induce the conformational equilibrium towards the axial or equatorial conformer. The interactions evaluated were hydrogen bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classical effects indeed rule the conformational equilibrium of the compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants, which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.

  19. Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

    Science.gov (United States)

    2013-01-01

    REPORT Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions 14. ABSTRACT 16. SECURITY...properties and of the attendant ballistic-impact failure mechanisms in prototypical friction stir welding (FSW) joints found in armor structures made of high...mechanisms, friction stir welding M. Grujicic, B. Pandurangan, A. Arakere, C-F. Yen, B. A. Cheeseman Clemson University Office of Sponsored Programs 300

  20. The Impact of Structured Activities among Palestinian Children in a Time of Conflict

    Science.gov (United States)

    Loughry, Maryanne; Ager, Alastair; Flouri, Eirini; Khamis, Vivian; Afana, Abdel Hamid; Qouta, Samir

    2006-01-01

    Background: There is growing evidence of the impact on children's well-being of exposure to political conflict in such settings as the Palestinian territories. This study examined the impact of child-focused interventions involving structured activities, supported by provision of equipment and training of facilitators. The focus of interventions…

  1. Understanding the Impact of Trauma Exposure on Posttraumatic Stress Symptomatology: A Structural Equation Modeling Approach

    Science.gov (United States)

    Chen, Wei; Wang, Long; Zhang, Xing-Li; Shi, Jian-Nong

    2012-01-01

    The objective of this study was to investigate the impact of trauma exposure on the posttraumatic stress symptomatology (PTSS) of children who resided near the epicenter of the 2008 Wenchuan earthquake. The mechanisms of this impact were explored via structural equation models with self-esteem and coping strategies included as mediators. The…

  2. Carbonate Melt Rocks from the Haughton Impact Structure, Devon Island, Nunavut, Canada

    Science.gov (United States)

    Osinski, G. R.; Spray, J. G.; Lee, P.

    2002-01-01

    The target rocks at the Haughton impact structure, Canada, are predominantly carbonates. The well preserved allochthonous crater-fill deposits are reinterpreted here as being carbonatitic impact melt rocks. The implications of our findings will be discussed. Additional information is contained in the original extended abstract.

  3. Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Méndez, M Soledad; Ballaré, Carlos L

    2016-04-19

    A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.

  4. Utilization of the terrestrial cyanobacteria

    Science.gov (United States)

    Katoh, Hiroshi; Tomita-Yokotani, Kaori; Furukawa, Jun; Kimura, Shunta; Yokoshima, Mika; Yamaguchi, Yuji; Takenaka, Hiroyuki

    The terrestrial, N _{2}-fixing cyanobacterium, Nostoc commune has expected to utilize for agriculture, food and terraforming cause of its extracellular polysaccharide, desiccation tolerance and nitrogen fixation. Previously, the first author indicated that desiccation related genes were analyzed and the suggested that the genes were related to nitrogen fixation and metabolisms. In this report, we suggest possibility of agriculture, using the cyanobacterium. Further, we also found radioactive compounds accumulated N. commune (cyanobacterium) in Fukushima, Japan after nuclear accident. Thus, it is investigated to decontaminate radioactive compounds from the surface soil by the cyanobacterium and showed to accumulate radioactive compounds using the cyanobacterium. We will discuss utilization of terrestrial cyanobacteria under closed environment. Keyword: Desiccation, terrestrial cyanobacteria, bioremediation, agriculture

  5. Food-web structure of seagrass communities across different spatial scales and human impacts.

    Science.gov (United States)

    Coll, Marta; Schmidt, Allison; Romanuk, Tamara; Lotze, Heike K

    2011-01-01

    Seagrass beds provide important habitat for a wide range of marine species but are threatened by multiple human impacts in coastal waters. Although seagrass communities have been well-studied in the field, a quantification of their food-web structure and functioning, and how these change across space and human impacts has been lacking. Motivated by extensive field surveys and literature information, we analyzed the structural features of food webs associated with Zostera marina across 16 study sites in 3 provinces in Atlantic Canada. Our goals were to (i) quantify differences in food-web structure across local and regional scales and human impacts, (ii) assess the robustness of seagrass webs to simulated species loss, and (iii) compare food-web structure in temperate Atlantic seagrass beds with those of other aquatic ecosystems. We constructed individual food webs for each study site and cumulative webs for each province and the entire region based on presence/absence of species, and calculated 16 structural properties for each web. Our results indicate that food-web structure was similar among low impact sites across regions. With increasing human impacts associated with eutrophication, however, food-web structure show evidence of degradation as indicated by fewer trophic groups, lower maximum trophic level of the highest top predator, fewer trophic links connecting top to basal species, higher fractions of herbivores and intermediate consumers, and higher number of prey per species. These structural changes translate into functional changes with impacted sites being less robust to simulated species loss. Temperate Atlantic seagrass webs are similar to a tropical seagrass web, yet differed from other aquatic webs, suggesting consistent food-web characteristics across seagrass ecosystems in different regions. Our study illustrates that food-web structure and functioning of seagrass habitats change with human impacts and that the spatial scale of food-web analysis

  6. Food-web structure of seagrass communities across different spatial scales and human impacts.

    Directory of Open Access Journals (Sweden)

    Marta Coll

    Full Text Available Seagrass beds provide important habitat for a wide range of marine species but are threatened by multiple human impacts in coastal waters. Although seagrass communities have been well-studied in the field, a quantification of their food-web structure and functioning, and how these change across space and human impacts has been lacking. Motivated by extensive field surveys and literature information, we analyzed the structural features of food webs associated with Zostera marina across 16 study sites in 3 provinces in Atlantic Canada. Our goals were to (i quantify differences in food-web structure across local and regional scales and human impacts, (ii assess the robustness of seagrass webs to simulated species loss, and (iii compare food-web structure in temperate Atlantic seagrass beds with those of other aquatic ecosystems. We constructed individual food webs for each study site and cumulative webs for each province and the entire region based on presence/absence of species, and calculated 16 structural properties for each web. Our results indicate that food-web structure was similar among low impact sites across regions. With increasing human impacts associated with eutrophication, however, food-web structure show evidence of degradation as indicated by fewer trophic groups, lower maximum trophic level of the highest top predator, fewer trophic links connecting top to basal species, higher fractions of herbivores and intermediate consumers, and higher number of prey per species. These structural changes translate into functional changes with impacted sites being less robust to simulated species loss. Temperate Atlantic seagrass webs are similar to a tropical seagrass web, yet differed from other aquatic webs, suggesting consistent food-web characteristics across seagrass ecosystems in different regions. Our study illustrates that food-web structure and functioning of seagrass habitats change with human impacts and that the spatial scale of

  7. Hydraulic modeling of flow impact on bridge structures: a case study on Citarum bridge

    Science.gov (United States)

    Siregar, R. I.

    2018-02-01

    Flood waves because of the rapid catchment response to high intense rainfall, breaches of flood defenses may induce huge impact forces on structures, causing structural damage or even failures. Overflowing stream that passes over the bridge, it means to discharge flood water level is smaller than the capacity of the river flow. In this study, the researches present the methodological approach of flood modeling on bridge structures. The amount of force that obtained because of the hydrostatic pressure received by the bridge at the time of the flood caused the bridge structure disrupted. This paper presents simulation of flow impact on bridge structures with some event flood conditions. Estimating the hydrostatic pressure developed new model components, to quantify the flow impact on structures. Flow parameters applied the model for analyzing, such as discharge, velocity, and water level or head that effect of bridge structures. The simulation will illustrate the capability of bridge structures with some event flood river and observe the behavior of the flow that occurred during the flood. Hydraulic flood modeling use HEC-RAS for simulation. This modeling will describe the impact on bridge structures. Based on the above modelling resulted, in 2008 has flood effect more than other years on the Citarum Bridge, because its flow overflow on the bridge.

  8. RESPONSE OF STRUCTURES TO HIGH VELOCITY IMPACTS: A GENERALIZED ALGORITHM

    Directory of Open Access Journals (Sweden)

    Aversh'ev Anatoliy Sergeevich

    2012-10-01

    Full Text Available In this paper, a high velocity impact produced by a spherical striker and a target are considered; different stages of loading and unloading, target deformations and propagation of non-stationary wave surfaces within the target are analyzed. The problem of the strike modeling and subsequent deformations is solved by using not only the equations of mechanics of deformable rigid bodies, but also fluid mechanics equations. The target material is simulated by means of an ideal "plastic gas". Modeling results and theoretical calculations are compared to the experimental results. The crater depth, its correlation with the striker diameter, values of the pressure and deformations of the target underneath the contact area are determined as the main characteristics of dynamic interaction.

  9. Communication Breakdown: The Impact of Ageing on Synapse Structure

    Science.gov (United States)

    Petralia, Ronald S.; Mattson, Mark P.; Yao, Pamela J.

    2014-01-01

    Impaired synaptic plasticity is implicated in the functional decline of the nervous system associated with ageing. Understanding the structure of ageing synapses is essential to understanding the functions of these synapses and their role in the ageing nervous system. In this review, we summarize studies on ageing synapses in vertebrates and invertebrates, focusing on changes in morphology and ultrastructure. We cover different parts of the nervous system, including the brain, the retina, the cochlea, and the neuromuscular junction. The morphological characteristics of aged synapses could shed light on the underlying molecular changes and their functional consequences. PMID:24495392

  10. Dynamical load factor of impact loaded shell structures

    International Nuclear Information System (INIS)

    Hammel, J.

    1977-01-01

    Dynamical loaded structures can be analysed by spectral representations, which usually lead to an enormous computational effort. If it is possible to find a fitting dynamical load factor, the dynamical problem can be reduced to a statical one. The computation of this statical problem is much simpler. The disadvantage is that the dynamical load factor usually leads to a very rough approximation. In this paper it will be shown, that by combination of these two methods, the approximation of the dynamical load factor can be improved and the consumption of computation time can be enormously reduced. (Auth.)

  11. Structural ambidexterity in NPD processes; A firm-level assessment of the impact of differentiated structures on innovation performance

    NARCIS (Netherlands)

    de Visser, Matthias; de Weerd-Nederhof, Petronella C.; Faems, D.L.M.; Song, Michael; Song, Michael; van Looy, Bart; van Looy, Bart; Visscher, Klaasjan

    2010-01-01

    Based on a survey study of 155 U.S. firms, we conducted a firm-level assessment of the impact of different kinds of structures (i.e., functional versus cross-functional) in different kinds of new product development (NPD) processes (i.e., incremental versus radical) on different kinds of firm

  12. A review of climate change effects on terrestrial rangeland birds

    Science.gov (United States)

    D. M. Finch; K. E. Bagne; M. M. Friggens; D. M. Smith; K. M. Brodhead

    2011-01-01

    We evaluated existing literature on predicted and known climate change effects on terrestrial rangeland birds. We asked the following questions: 1) How does climate change affect birds? 2) How will birds respond to climate change? 3) Are species already responding? 4) How will habitats be impacted?

  13. Serine protease from midgut of Bombus terrestris males

    Czech Academy of Sciences Publication Activity Database

    Brabcová, Jana; Kindl, Jiří; Valterová, Irena; Pichová, Iva; Zarevúcka, Marie; Brabcová, J.; Jágr, Michal; Mikšík, Ivan

    2013-01-01

    Roč. 82, č. 3 (2013), s. 117-128 ISSN 0739-4462 R&D Projects: GA ČR GA203/09/1446; GA TA ČR TA01020969 Institutional support: RVO:61388963 ; RVO:67985823 Keywords : Bombus terrestris * midgut * serine protease * bumblebee Subject RIV: CE - Biochemistry; CE - Biochemistry (FGU-C) Impact factor: 1.160, year: 2013

  14. Climate control of terrestrial carbon exchange across biomes and continents

    Czech Academy of Sciences Publication Activity Database

    Yi, C.; Ricciuto, D.; Marek, Michal V.

    2010-01-01

    Roč. 5, č. 3 (2010), s. 034007 ISSN 1748-9326 Institutional research plan: CEZ:AV0Z60870520 Keywords : NEE * climate control * terrestrial carbon sequestration * temperature * dryness * eddy flux * biomes * photosynthesis * respiration * global carbon cycle Subject RIV: EH - Ecology, Behaviour Impact factor: 3.049, year: 2010

  15. Soil and terrestrial biology studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Soil and terrestrial biology studies focused on developing an understanding of the uptake of gaseous substances from the atmosphere by plants, biodegradation of oil, and the movement of Pu in the terrestrial ecosystems of the southeastern United States. Mathematical models were developed for SO 2 and tritium uptake from the atmosphere by plants; the uptake of tritium by soil microorganisms was measured; and the relationships among the Pu content of soil, plants, and animals of the Savannah River Plant area were studied. Preliminary results are reported for studies on the biodegradation of waste oil on soil surfaces

  16. Priapism caused by 'Tribulus terrestris'.

    Science.gov (United States)

    Campanelli, M; De Thomasis, R; Tenaglia, R L

    2016-01-01

    A 36-year-old Caucasian man was diagnosed with a 72-h-lasting priapism that occurred after the assumption of a Herbal supplement based on Tribulus terrestris, which is becoming increasingly popular for the treatment of sexual dysfunction. The patient underwent a cavernoglandular shunt (Ebbehoj shunt) in order to obtain complete detumescence, from which derived negative post-episode outcomes on sexual function. All patients consuming non-FDA-approved alternative supplements such as Tribulus terrestris should be warned about the possible serious side effects.

  17. Advances in imaging: impact on studying craniofacial bone structure.

    Science.gov (United States)

    Majumdar, S

    2003-01-01

    Methods for measuring the structure of craniofacial bones are discussed in this paper. In addition to the three-dimensional macro-structure of the craniofacial skeleton, there is considerable interest in imaging the bone at a microscopic resolution in order to depict the micro-architecture of the trabecular bone itself. In addition to the density of the bone, the microarchitecture reflects bone quality. An understanding of bone quality and density changes has implications for a number of craniofacial pathologies, as well as for implant design and understanding the biomechanical function and loading of the jaw. Trabecular bone micro-architecture has been recently imaged using imaging methods such as micro-computed tomography, magnetic resonance imaging, and the images have been used in finite element models to assess bone mechanical properties. In this paper, some of the recent advances in micro-computed tomography and magnetic resonance imaging are reviewed, and their potential for imaging the trabecular bone in mandibular bones is presented. Examples of in vitro and in vivo images are presented.

  18. Sloshing, fluid-structure interaction and structural response due to shock and impact loads 1994. PVP-Vol. 272

    International Nuclear Information System (INIS)

    Ma, D.C.; Shin, Y.S.; Brochard, D.; Fujita, K.

    1994-01-01

    This volume is comprised of papers presented in two symposia at the 1994 ASME Pressure Vessels and Piping Conference. These sessions, sponsored by the Fluid-Structure Interaction and Seismic Engineering Technical Committees, provided a forum for the discussion of recent advances in sloshing, fluid-structure interaction, and structural dynamics produced by high energy excitations. The papers presented at the four technical sessions on Sloshing and Fluid-Structure Interaction represent a broad spectrum of fluid-structure systems: sloshing, fluid-structure interaction, and dynamic and seismic response of various fluid-structure systems such as reactor components, liquid storage tanks, submerged structures and piping systems, etc. The paper presented at the session on Structural Dynamics Produced by High-Energy Excitations cover underwater explosion effects on submerged structures, bubble loading phenomena, finite element mesh refinements on failure predictions, penetration and impact problems, and dynamic design of blast containment vessels. Also included are numerical analysis, design, and testing to understand difficult transient response phenomena. Separate abstracts were prepared for 24 papers in this volume

  19. Impact of metal pollution on fungal diversity and community structures.

    Science.gov (United States)

    Op De Beeck, Michiel; Lievens, Bart; Busschaert, Pieter; Rineau, Francois; Smits, Mark; Vangronsveld, Jaco; Colpaert, Jan V

    2015-06-01

    The impact of metal pollution on plant communities has been studied extensively in the past, but little is known about the effects of metal pollution on fungal communities that occur in metal-polluted soils. Metal-tolerant ecotypes of the ectomycorrhizal fungus Suillus luteus are frequently found in pioneer pine forests in the Campine region in Belgium on metal-polluted soils. We hypothesized that metal pollution would play an important role in shaping below-ground fungal communities that occur in these soils and that Suillus luteus would be a dominant player. To test these hypotheses, the fungal communities in a young pine plantation in soil polluted with zinc, and cadmium were studied using 454 amplicon pyrosequencing. Results show that zinc, cadmium and soil organic matter content were strongly correlated with the fungal community composition, but no effects on fungal diversity were observed. As hypothesized, S. luteus was found to be a dominant member of the studied fungal communities. However, other dominant fungal species, such as Sistotrema sp., Wilcoxina mikolae and Cadophora finlandica were found as well. Their presence in metal-polluted sites is discussed. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. THE IMPACT OF COMPENSATION PAYMENTS ON EMPLOYMENT, IN REGIONAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    Nicoleta JULA

    2015-07-01

    Full Text Available Compensation payments are considered active labour market policies designed to increase efficiency, to mitigate unemployment and to sustaining employment. We tested this hypothesis for the period 1993-2013, in territorial structures (42 counties through a dynamic panel model (confirmed by Granger causality tests – Toda-Yamamoto version, and by means of error correction model. We found that the dynamics of regional employment are positively related to expenditure incurred for active policies and there are negatively correlated with the ratio between the unemployment average indemnity (and support allowance and the average net nominal monthly salary earnings. But, the connexion between employment and compensation payments converges extremely slowly for a long-term stable relationship.

  1. Impacts of Power Structure on Sustainable Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2017-12-01

    Full Text Available The present paper examines the manufacturer’s operational decisions, e.g., wholesale price and product sustainability level, the retailer’s operational decision, e.g., retail margin, and supply chain efficiency under three supply chain power structures: manufacturer Stackelberg, Nash and retailer Stackelberg. As a benchmark, we first obtain the equlibrium price and product sustainability level in a vertically integrated supply chain. Our analysis provides some interesting findings in a decentralized supply chain: (i a dominant manufacturer (retailer always benefits from its power; (ii the entire supply chain earns the most profit from the Nash game, and the least from the retailer Stackelberg game, respectively; (iii as the power shifts from the manufacturer to the retailer, product sustainability and retail price increase; (iv dominant manufacturer does not necessarily imply low wholesale price that would benefit the retailer. Managerial insights are provided for the manufacturer and the retailer, respectively.

  2. The impact of firm and industry characteristics on small firms' capital structure

    NARCIS (Netherlands)

    Degryse, H.A.; de Goeij, P. C.; Kappert, P.

    2012-01-01

    We study the impact of firm and industry characteristics on small firms’ capital structure, employing a proprietary database containing financial statements of Dutch small and medium-sized enterprises (SMEs) from 2003 to 2005. The firm characteristics suggest that the capital structure decision is

  3. An analysis of burn-off impact on the structure microporous of activated carbons formation

    Science.gov (United States)

    Kwiatkowski, Mirosław; Kopac, Türkan

    2017-12-01

    The paper presents the results on the application of the LBET numerical method as a tool for analysis of the microporous structure of activated carbons obtained from a bituminous coal. The LBET method was employed particularly to evaluate the impact of the burn-off on the obtained microporous structure parameters of activated carbons.

  4. Experiencing the Impact of Organizational Structure on Planning and Visioning Tasks

    Science.gov (United States)

    Pennisi, Lisa

    2012-01-01

    The various ways natural resource agencies and programs are structured and how that impacts leadership style and products is an important concept for students to understand. Leadership style and organizational structure determine visions, missions, goals and objectives that set the tone for organizations. This exercise demonstrates organizational…

  5. Structural impact response for assessing railway vibration induced on buildings

    Science.gov (United States)

    Kouroussis, Georges; Mouzakis, Harris P.; Vogiatzis, Konstantinos E.

    2018-03-01

    Over the syears, the rapid growth in railway infrastructure has led to numerous environmental challenges. One such significant issue, particularly in urban areas, is ground-borne vibration. A common source of ground-borne vibration is caused by local defects (e.g. rail joints, switches, turnouts, etc.) that generate large amplitude excitations at isolated locations. Modelling these excitation sources is particularly challenging and requires the use of complex and extensive computational efforts. For some situations, the use of experiments and measured data offers a rapid way to estimate the effect of such defects and to evaluate the railway vibration levels using a scoping approach. In this paper, the problem of railway-induced ground vibrations is presented along with experimental studies to assess the ground vibration and ground borne noise levels, with a particular focus on the structural response of sensitive buildings. The behaviour of particular building foundations is evaluated through experimental data collected in Brussels Region, by presenting the expected frequency responses for various types of buildings, taking into account both the soil-structure interaction and the tramway track response. A second study is dedicated to the Athens metro, where transmissibility functions are used to analyse the effect of various Athenian building face to metro network trough comprehensive measurement campaigns. This allows the verification of appropriate vibration mitigation measures. These benchmark applications based on experimental results have been proved to be efficient to treat a complex problem encountered in practice in urban areas, where the urban rail network interacts with important local defects and where the rise of railway ground vibration problems has clearly been identified.

  6. Impact velocity vs. target hardness relationships for equivalent response of cask structures

    International Nuclear Information System (INIS)

    Chen, T.F.; Chen, J.C.; Witte, M.C.; Fischer, L.E.

    1993-01-01

    In this paper, impact velocity vs. target hardness relationships for cask structures are reviewed. The relationships are based on equivalent cask responses in terms of equal deceleration or similar cask damages. By examining several past cask or container tests as well as some analytical results, some conclusions can be drawn about the relationship between target hardness and equivalent impact velocities. This relationship clearly shows that the cask response to impact is cask-dependent and that the rigid sphere impact model results in an unconservative estimate of equivalent velocity

  7. Impacts of initial convective structure on subsequent squall line evolution

    Science.gov (United States)

    Varble, A.; Morrison, H.; Zipser, E. J.

    2017-12-01

    A Weather Research and Forecasting simulation of the 20 May 2011 MC3E squall line using 750-m horizontal grid spacing produces wide convective regions with strongly upshear tilted convective updrafts and mesoscale bowing segments that are not produced in radar observations. Similar features occur across several different bulk microphysics schemes, despite surface observations exhibiting cold pool equivalent potential temperature drops that are similar to and pressure rises that are greater than those in the simulation. Observed rear inflow remains more elevated than simulated, partly counteracting the cold pool circulation, whereas the simulated rear inflow descends to low levels, maintaining its strength and reinforcing the cold pool circulation that overpowers the pre-squall line low level vertical wind shear. The descent and strength of the simulated rear inflow is fueled by strong latent cooling caused by large ice water contents detrained from upshear tilted convective cores that accumulate at the rear of the stratiform region. This simulated squall evolution is sensitive to model resolution, which is too coarse to resolve individual convective drafts. Nesting a 250-m horizontal grid spacing domain into the 750-m domain substantially alters the initial convective cells with reduced latent cooling, weaker convective downdrafts, and a weaker initial cold pool. As the initial convective cells develop into a squall line, the rear inflow remains more elevated in the 250-m domain with a cold pool that eventually develops to be just as strong and deeper than the one in the 750-m run. Despite this, the convective cores remain more upright in the 250-m run with the rear inflow partly counteracting the cold pool circulation, whereas the 750-m rear inflow near the surface reinforces the shallower cold pool and causes bowing in the squall line. The different structure in the 750-m run produces excessive mid-level front-to-rear detrainment that widens the convective region

  8. The Impact of capital structure on the performance efficiency of Baltic listed companies

    OpenAIRE

    Norvaišienė, Rasa

    2012-01-01

    The capital structure can influence the behavior of the company as well as its performance results and its value. However, the effect can be quite different. The financial indicators of Lithuanian, Latvian and Estonian listed companies published in their annual reports have been used in order to investigate the impact of capital structure on performance efficiency of the companies. The research included data of only non-financial companies, because the capital structure of financial instituti...

  9. Evaluating the impact of investments in information technology on structural inertia in health organizations.

    Science.gov (United States)

    Bewley, Lee W

    2010-01-01

    Structural inertia is the overall capacity of an organization to adapt within a market environment. This paper reviews the impact of healthcare investments in information management/information technology (IM/IT) on the strategic management concept of structural inertia. Research indicates that healthcare executives should consider the relative state of structural inertia for their firms and match them with potential IM/IT solutions. Additionally, organizations should favorably consider IM/IT solutions that are comparatively less complex.

  10. Intensification of steam explosion and structural intricacies impacting sugar recovery.

    Science.gov (United States)

    Gaur, Ruchi; Semwal, Surbhi; Raj, Tirath; Yadav Lamba, Bhawna; Ramu, E; Gupta, Ravi P; Kumar, Ravindra; Puri, Suresh K

    2017-10-01

    Dilute acid (DA) pretreatment at pilot level failed for cotton stalk (CS) due to the technical issues posed by its inherent nature. Reasonable glucan conversion has been reported via two-stage pretreatment but adds on to the process cost. Proposed herewith is a single-stage steam explosion (SE) process preceded by water extraction resulting in high sugar recovery from CS. Raising the extraction temperature to 80°C increased the glucan conversion from 37.9 to 52.4%. Further improvement up to 68.4% was achieved when DA was incorporated during the room temperature extraction. LC-MS revealed the formation of xylo-oligomers limiting the glucan conversion in proportion to the length of xylo-oligomers. Varying extraction conditions induced structural alterations in biomass after SE evident by compositional analysis, Infrared Spectroscopy, X-Ray Diffraction and Scanning Electron Microscopy. Overall glucose recovery, i.e. 75.8-76.7% with and without DA extraction respectively was achieved. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Workplace experience of radiographers: impact of structural and interpersonal interventions

    Energy Technology Data Exchange (ETDEWEB)

    Kubik-Huch, R.A.; Roempler, M.; Weber, A. [Kantonsspital Baden, Institute of Radiology, Baden (Switzerland); Klaghofer, R.; Buddeberg-Fischer, B. [Zurich University Hospital, Department of Psychosocial Medicine, Zurich (Switzerland)

    2010-02-15

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  12. Hazardous E-waste and its impact on soil structure

    Science.gov (United States)

    Dharini, K.; Cynthia, J. Bernadette; Kamalambikai, B.; Sudar Celestina, J. P. Arul; Muthu, D.

    2017-07-01

    E-waste disposal has been a significant issue over the past few decades with the development of technology and the plethora of electronic products produced. The inclusive term E-Waste encapsulates various forms of electrical and electronical equipment which provides no value to the current owners and it is one among the fastest growing waste streams. E-Waste is a complex, non-biodegradable waste which is generally dumped in mountain like heaps. These wastes are said to have a large quantities of lead, cadmium, arsenic etc.it is mandatory to dispose such scrupulously since they have the ability to affect the soil and water parameters. Solid waste management is a blooming field which strives to reduce the accumulation of used electronic gadgets. Rainwater gets infiltrated through the e-waste landfill and it leaches through the soil which in turn reaches the groundwater directly thereby affecting the water intended for drinking and domestic purposes. This study focuses on the consequences of toxic waste by comparing the difference in properties of the soil structure prior to and after the e-waste landfill at various concentrations.

  13. Workplace experience of radiographers: impact of structural and interpersonal interventions

    International Nuclear Information System (INIS)

    Kubik-Huch, R.A.; Roempler, M.; Weber, A.; Klaghofer, R.; Buddeberg-Fischer, B.

    2010-01-01

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  14. Characterisation of fluid-structure interaction for water impact of composite panels

    Directory of Open Access Journals (Sweden)

    M Battley

    2016-09-01

    Full Text Available Hydrodynamic loads can be very significant for high performance marine vessels. Water impact of panels, known as "slamming", typically generates high magnitude short duration pressure pulses that move across the structure. In the case of compliant panels there can be significant coupling between the pressures and the structural responses. While there has been significant development of numerical methods to simulate this type of fluid-structure interaction there is only very limited experimental data available for validation of the simulation approaches. This paper describes an experimental study of sandwich composite panels subjected to water slamming impacts. The results demonstrate that compliant panels subjected to water slamming impacts experience different pressures than rigid panels, and have different structural responses than predicted by traditional uniform pressure based analysis approaches. The study also characterizes the significant effects that the dimensions of pressure transducers and data acquisition sampling rates have on the measured pressures.

  15. Impact of soil-structure interaction on the probabilistic frequency variation of concrete structures

    International Nuclear Information System (INIS)

    Hadjian, A.H.; Hamilton, C.W.

    1975-01-01

    Earthquake response of equipment in nuclear power plants is characterized by floor response spectra. Since these spectra peak at the natural frequencies of the structure, it is important, both from safety and cost standpoints, to determine the degree of the expected variability of the calculated structural frequencies. A previous work is extended on the variability of the natural frequencies of structures due to the variations of concrete properties and a rigorous approach is presented to evaluate frequency variations based on the probability distributions of both the structural and soil parameters and jointly determine the distributions of the natural frequencies. It is assumed that the soil-structure interaction coefficients are normally distributed. With the proper choice of coordinates, the simultaneous random variations of both the structural properties and the interaction coefficients can be incorporated in the eigenvalue problem. The key methodology problem is to obtain the probability distribution of eigenvalues of matrices with random variable elements. Since no analytic relation exists between the eigenvalues and the elements, a numerical procedure had to be designed. It was found that the desired accuracy can be best achieved by splitting the joint variation into two parts: the marginal distribution of soil variations and the conditional distribution of structural variations at specific soil fractiles. Then after calculating the actual eigenvalues at judiciously selected paired values of soil and structure parameters, this information is recombined to obtain the desired cumulative distribution of natural frequencies

  16. Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

    International Nuclear Information System (INIS)

    Ellingwood, B.; Song, J.

    1996-03-01

    The Structural Aging Program is addressing the potential for degradation of concrete structural components and systems in nuclear power plants over time due to aging and aggressive environmental stressors. Structures are passive under normal operating conditions but play a key role in mitigating design-basis events, particularly those arising from external challenges such as earthquakes, extreme winds, fires and floods. Structures are plant-specific and unique, often are difficult to inspect, and are virtually impossible to replace. The importance of structural failures in accident mitigation is amplified because such failures may lead to common-cause failures of other components. Structural condition assessment and service life prediction must focus on a few critical components and systems within the plant. Components and systems that are dominant contributors to risk and that require particular attention can be identified through the mathematical formalism of a probabilistic risk assessment, or PRA. To illustrate, the role of structural degradation due to aging on plant risk is examined through the framework of a Level 1 seismic PRA of a nuclear power plant. Plausible mechanisms of structural degradation are found to increase the core damage probability by approximately a factor of two

  17. Designing, implementing and monitoring social impact mitigation strategies: Lessons from Forest Industry Structural Adjustment Packages

    International Nuclear Information System (INIS)

    Loxton, Edwina A.; Schirmer, Jacki; Kanowski, Peter

    2013-01-01

    Social impact mitigation strategies are implemented by the proponents of policies and projects with the intent of reducing the negative, and increasing the positive social impacts of their activities, and facilitating the achievement of policy/project goals. Evaluation of mitigation strategies is critical to improving their future success and cost-effectiveness. This paper evaluates two Forest Industry Structural Adjustment Packages (FISAP) implemented in Australia in the 1990s to 2000s as part of broader policy changes that reduced access to timber from publicly owned native forests. It assesses the effectiveness of the structure, design, implementation and monitoring of the FISAPs, and highlights the interactions between these four elements and their influence on social impacts. The two FISAPs were found to be effective in terms of reducing negative impacts, encouraging positive impacts and contributing towards policy goals, although they did not mitigate negative impacts in all cases, and sometimes interacted with external factors and additional policy changes to contribute to significant short and long term negative impacts. -- Highlights: ► Mitigation strategies aim to reduce negative and enhance positive social impacts ► Mitigation strategy design, implementation, and monitoring are critical to success ► Effective mitigation enhanced the capacity of recipients to respond to change ► Mitigation strategies influenced multiple interacting positive and negative impacts ► Success required good communication, transparency, support, resources and timing

  18. The Impact of Embedded Story Structures versus Sequential Story Structures on Critical Thinking of Iranian Intermediate EFL Learners

    Directory of Open Access Journals (Sweden)

    Sara Samadi

    2016-09-01

    Full Text Available Confirming the constructive effects of reading comprehension on critical thinking, this paper attempted to investigate the impact of story structures on critical thinking of Iranian EFL learners. In doing so, the researcher utilized a quasi–experimental design with 60 intermediate students who were divided into two embedded story structures and sequential story structures groups (experimental groups. After taking PET, a critical thinking questionnaire was employed as a pre-test. The two groups received 16 sessions of treatment. All participants received similar amount of instruction but one group was given embedded short stories and the other group sequential short stories. To compare the two groups, they were received the parallel critical thinking questionnaire as a post-test. The two null hypotheses in this study were rejected due to different performance of the two groups. Statistical results did not support the superiority of neither structures. Therefore, the researcher was not able to suggest which structure caused a better or higher impact on critical thinking. However, the findings reveal that teaching story structures in EFL context can develop critical thinking of intermediate EFL learners. The study have some implications for test-designers, teachers, and students.

  19. Generating spatial precipitation ensembles: impact of temporal correlation structure

    Science.gov (United States)

    Rakovec, O.; Hazenberg, P.; Torfs, P. J. J. F.; Weerts, A. H.; Uijlenhoet, R.

    2012-09-01

    Sound spatially distributed rainfall fields including a proper spatial and temporal error structure are of key interest for hydrologists to force hydrological models and to identify uncertainties in the simulated and forecasted catchment response. The current paper presents a temporally coherent error identification method based on time-dependent multivariate spatial conditional simulations, which are conditioned on preceding simulations. A sensitivity analysis and real-world experiment are carried out within the hilly region of the Belgian Ardennes. Precipitation fields are simulated for pixels of 10 km × 10 km resolution. Uncertainty analyses in the simulated fields focus on (1) the number of previous simulation hours on which the new simulation is conditioned, (2) the advection speed of the rainfall event, (3) the size of the catchment considered, and (4) the rain gauge density within the catchment. The results for a sensitivity analysis show for typical advection speeds >20 km h-1, no uncertainty is added in terms of across ensemble spread when conditioned on more than one or two previous hourly simulations. However, for the real-world experiment, additional uncertainty can still be added when conditioning on a larger number of previous simulations. This is because for actual precipitation fields, the dynamics exhibit a larger spatial and temporal variability. Moreover, by thinning the observation network with 50%, the added uncertainty increases only slightly and the cross-validation shows that the simulations at the unobserved locations are unbiased. Finally, the first-order autocorrelation coefficients show clear temporal coherence in the time series of the areal precipitation using the time-dependent multivariate conditional simulations, which was not the case using the time-independent univariate conditional simulations. The presented work can be easily implemented within a hydrological calibration and data assimilation framework and can be used as an

  20. Generating spatial precipitation ensembles: impact of temporal correlation structure

    Directory of Open Access Journals (Sweden)

    O. Rakovec

    2012-09-01

    Full Text Available Sound spatially distributed rainfall fields including a proper spatial and temporal error structure are of key interest for hydrologists to force hydrological models and to identify uncertainties in the simulated and forecasted catchment response. The current paper presents a temporally coherent error identification method based on time-dependent multivariate spatial conditional simulations, which are conditioned on preceding simulations. A sensitivity analysis and real-world experiment are carried out within the hilly region of the Belgian Ardennes. Precipitation fields are simulated for pixels of 10 km × 10 km resolution. Uncertainty analyses in the simulated fields focus on (1 the number of previous simulation hours on which the new simulation is conditioned, (2 the advection speed of the rainfall event, (3 the size of the catchment considered, and (4 the rain gauge density within the catchment. The results for a sensitivity analysis show for typical advection speeds >20 km h−1, no uncertainty is added in terms of across ensemble spread when conditioned on more than one or two previous hourly simulations. However, for the real-world experiment, additional uncertainty can still be added when conditioning on a larger number of previous simulations. This is because for actual precipitation fields, the dynamics exhibit a larger spatial and temporal variability. Moreover, by thinning the observation network with 50%, the added uncertainty increases only slightly and the cross-validation shows that the simulations at the unobserved locations are unbiased. Finally, the first-order autocorrelation coefficients show clear temporal coherence in the time series of the areal precipitation using the time-dependent multivariate conditional simulations, which was not the case using the time-independent univariate conditional simulations. The presented work can be easily implemented within a hydrological calibration and data assimilation

  1. The impacts of multiple stressors to model ecological structures

    International Nuclear Information System (INIS)

    Landis, W.G.; Kelly, S.A.; Markiewicz, A.J.; Matthews, R.A.; Matthews, G.B.

    1995-01-01

    The basis of the community conditioning hypothesis is that ecological structures are the result of their unique etiology. Systems that have been exposed to a variety of stressors should reflect this history. The authors how conducted a series of microcosm experiments that can compare the effects of multiple stressors upon community dynamics. The microcosm protocols are derived from the Standardized Aquatic Microcosm (SAM) and have Lemma and additional protozoan species. Two multiple stressor experiments have been conducted. In an extended length SAM (ELSAM), two of four treatments were dosed with the turbine fuel JP-8 one week into the experiment. Two treatments were later exposed to the heat stress, one that had received jet fuel and one that had not. Similarly, an ELSAM was conducted with the second stressor being the further addition of JP-8 replacing the heat shock. Biological, physical and chemical data were analyzed with multivariate techniques including nonmetric clustering and association analysis. Space-time worms and phase diagrams were also employed to ascertain the dynamic relationships of variables identified as important by the multivariate techniques. The experiments do not result in a simple additive linear response to the additional stressor. Examination of the relative population dynamics reveal alterations in trajectories that suggest treatment related effects. As in previous single stressor experiments, recovery does not occur even after extended experimental periods. The authors are now attempting to measure the resulting trajectories, changes in similarity vectors and overall dynamics. However, community conditioning does appear to be an important framework in understanding systems with a heterogeneous array of stressors

  2. Local Impact Simulation of SC Wall Structures using Aircraft Engine Projectile

    International Nuclear Information System (INIS)

    Chung, Chulhun; Lee, Jungwhee; Lee, Hanjoo; Jung, Raeyoung; Hyun, Changhun

    2013-01-01

    SC wall structure developed for nuclear power plant buildings consists of plain concrete and two steel plates on both surface of the concrete, while RC structure consists of re bar and concrete. SC structure has higher scabbing resistance than RC structure due to the action of steel plate on the rear side of impact. Therefore SC structure is known as more effective structure from the viewpoint of aircraft crash than RC structure. However, most of the recent researches and experiments about local impact damage deal with RC structures, and the effect of re bar and steel plate is not considered reasonably. Although Walter et al. and Make-work et al. suggested a formula for evaluating perforation depth of steel plate covered RC walls, most of the previous researches about SC structure are focused on perforation and scabbing due to the impact of hard projectile, rather than soft projectile such as an aircraft. In this research a soft projectile, i. e. aircraft engine, is utilized for impact simulation of RC and SC walls. To evaluate local damage of SC wall structures, parametric study with the variables of wall thickness and steel ratio of the cover plate is performed, and the results are compared with those of RC structures. Since scabbing was prevented by the steel plates, penetration mode of damage was observed in SC walls while scabbing damage was occurred in RC walls. It is confirmed that the rear steel plate not only contains concrete debris, but also reduces the internal damage of the concrete walls. Penetration depth of SC walls did not largely vary due to the increasing steel ratio, and similar results to RC walls were observed when the wall thickness is larger than a certain value since the impact resistance of SC wall is mainly governed by the thickness of concrete part. Therefore, it is expected that similar level of impact resistance to RC structure can be produced with the minimum thickness of steel plates of SC structure. According to these results, SC

  3. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  4. The Planetary Terrestrial Analogues Library (PTAL)

    Science.gov (United States)

    Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

    2018-04-01

    The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

  5. Evaluation of the Impact of the EU Structural Support on the Competitiveness of Lithuanian Economics

    Directory of Open Access Journals (Sweden)

    Rita Remeikiene

    2016-06-01

    Full Text Available Increasing amounts of the EU structural support in Lithuania require theoretical and practical research to disclose the determinants that have a significant impact on the competitiveness of Lithuanian economics. The purpose of this article is to evaluate the impact of the EU structural support on the competitiveness of Lithuanian economics. The methods of the research include systematic and comparative analysis of the scientific literature, expert evaluation and linear regression. The research disclosed the main determinants of country’s competitiveness. The results have revealed that EU structural support has the most significant impact on Lithuanian engineering and technological infrastructure. The impact of the support on country’s macroeconomic, scientific and social environment can also be considered as significant. The EU structural support has medium strong impact on education and business environment conditions in Lithuania. It has been established that, in the field of business advancement, Lithuanian should be rated as medium competitive. Hence, the increase in country’s competitiveness by employing EU structural funds should be treated as one of priority aims. In addition, responsible authorities should perform with higher efficiency seeking for higher competitiveness of the country.

  6. Terrestrial Steering Group. 2014. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Aastrup, Peter; Aronsson, Mora; Barry, Tom

    capacity and information may be currently available and (b) to outline near-term required steps to begin implementing the plan and reporting on an initial set of Arctic terrestrial biodiversity focal ecosystem component attributes. The specific objectives of the workshop were to: Identify key products...... for TSG for the next two years. Identify key components of a pan-Arctic status report for priority focal ecosystem components (FEC) attributes for policy and decision makers. Develop a prioritized set of activities to meet reporting objectives. Identify key milestones and timelines for the successful...... implementation of the Arctic Terrestrial Biodiversity Monitoring Plan for the next two years. Identify expert networks required for successful implementation of the plan. Identify key gaps and opportunities for the TSG related to plan implementation and identify near-term next steps to address gaps....

  7. Degradation Factor Approach for Impacted Composite Structural Assessment: MSFC Center Director's Discretionary Fund Final Report, Project No. 96-17

    Science.gov (United States)

    Ortega, R.; Price, J. M.; Fox, D.

    2000-01-01

    This technical memorandum documents the results of the research to develop a concept for assessing the structural integrity of impacted composite structures using the strength degradation factor in conjunction with available finite element tools. For this purpose, a literature search was conducted, a plan for conducting impact testing on two laminates was developed, and a finite element model of the impact process was created. Specimens for the impact testing were fabricated to support the impact testing plan.

  8. Direct and terrestrial vegetation-mediated effects of environmental change on aquatic ecosystem processes

    Science.gov (United States)

    Becky A. Ball; John S. Kominoski; Heather E. Adams; Stuart E. Jones; Evan S. Kane; Terrance D. Loecke; Wendy M. Mahaney; Jason P. Martina; Chelse M. Prather; Todd M.P. Robinson; Christopher T. Solomon

    2010-01-01

    Global environmental changes have direct effects on aquatic ecosystems, as well as indirect effects through alterations of adjacent terrestrial ecosystem structure and functioning. For example, shifts in terrestrial vegetation communities resulting from global changes can affect the quantity and quality of water, organic matter, and nutrient inputs to aquatic...

  9. Implications of sensor configuration and topography on vertical plant profiles derived from terrestrial LiDAR

    NARCIS (Netherlands)

    Calders, K.; Armston, J.; Newnham, G.; Herold, M.; Goodwin, N.

    2014-01-01

    The vertical distribution of plant constituents is a key parameter to describe vegetation structure and influences several processes, such as radiation interception, growth and habitat. Terrestrial laser scanning (TLS), also referred to as terrestrial LiDAR, has the potential to measure the canopy

  10. Data acquisition considerations for Terrestrial Laser Scanning of forest plots

    NARCIS (Netherlands)

    Wilkes, Phil; Lau Sarmiento, Alvaro; Disney, Mathias; Calders, Kim; Burt, Andrew; Gonzalez De Tanago Meñaca, J.; Bartholomeus, Harm; Brede, Benjamin; Herold, Martin

    2017-01-01

    The poor constraint of forest Above Ground Biomass (AGB) is responsible, in part, for large uncertainties in modelling future climate scenarios. Terrestrial Laser Scanning (TLS) can be used to derive unbiased and non-destructive estimates of tree structure and volume and can, therefore, be used to

  11. Geophysical survey of the proposed Tsenkher impact structure, Gobi Altai, Mongolia

    Science.gov (United States)

    Ormö, Jens; Gomez-Ortiz, David; Komatsu, Goro; Bayaraa, Togookhuu; Tserendug, Shoovdor

    2010-03-01

    We have performed forward magnetic and gravity modeling of data obtained during the 2007 expedition to the 3.7km in diameter, circular, Tsenkher structure, Mongolia, in order to evaluate the cause of its formation. Extensive occurrences of brecciated rocks, mainly in the form of an ejecta blanket outside the elevated rim of the structure, support an explosive origin (e.g., cosmic impact, explosive volcanism). The host rocks in the area are mainly weakly magnetic, silica-rich sandstones, and siltstones. A near absence of surface exposures of volcanic rocks makes any major volcanic structures (e.g., caldera) unlikely. Likewise, the magnetic models exclude any large, subsurface, intrusive body. This is supported by an 8mGal gravity low over the structure indicating a subsurface low density body. Instead, the best fit is achieved for a bowl-shaped structure with a slight central rise as expected for an impact crater of this size in mainly sedimentary target. The structure can be either root-less (i.e., impact crater) or rooted with a narrow feeder dyke with relatively higher magnetic susceptibility and density (i.e., volcanic maar crater). The geophysical signature, the solitary appearance, the predominantly sedimentary setting, and the comparably large size of the Tsenkher structure favor the impact crater alternative. However, until mineralogical/geochemical evidence for an impact is presented, the maar alternative remains plausible although exceptional as it would make the Tsenkher structure one of the largest in the world in an unusual setting for maar craters.

  12. On a digital wireless impact-monitoring network for large-scale composite structures

    International Nuclear Information System (INIS)

    Yuan, Shenfang; Mei, Hanfei; Qiu, Lei; Ren, Yuanqiang

    2014-01-01

    Impact, which may occur during manufacture, service or maintenance, is one of the major concerns to be monitored throughout the lifetime of aircraft composite structures. Aiming at monitoring impacts online while minimizing the weight added to the aircraft to meet the strict limitations of aerospace engineering, this paper puts forward a new digital wireless network based on miniaturized wireless digital impact-monitoring nodes developed for large-scale composite structures. In addition to investigations on the design methods of the network architecture, time synchronization and implementation method, a conflict resolution method based on the feature parameters of digital sequences is first presented to address impact localization conflicts when several nodes are arranged close together. To verify the feasibility and stability of the wireless network, experiments are performed on a complex aircraft composite wing box and an unmanned aerial vehicle (UAV) composite wing. Experimental results show the successful design of the presented network. (paper)

  13. Cumulus convection and the terrestrial water-vapor distribution

    Science.gov (United States)

    Donner, Leo J.

    1988-01-01

    Cumulus convection plays a significant role in determining the structure of the terrestrial water vapor field. Cumulus convection acts directly on the moisture field by condensing and precipitating water vapor and by redistributing water vapor through cumulus induced eddy circulations. The mechanisms by which cumulus convection influences the terrestrial water vapor distribution is outlined. Calculations using a theory due to Kuo is used to illustrate the mechanisms by which cumulus convection works. Understanding of these processes greatly aids the ability of researchers to interpret the seasonal and spatial distribution of atmospheric water vapor by providing information on the nature of sources and sinks and the global circulation.

  14. A compilation of structural property data for computer impact calculation (3/5)

    International Nuclear Information System (INIS)

    Ikushima, Takeshi

    1988-10-01

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 3 involve structural property data of stainless steel. (author)

  15. A compilation of structural property data for computer impact calculation (2/5)

    International Nuclear Information System (INIS)

    Ikushima, Takeshi

    1988-10-01

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 2 involve structural property data of mild steel. (author)

  16. A compilation of structural property data for computer impact calculation (1/5)

    International Nuclear Information System (INIS)

    Ikushima, Takeshi; Nagata, Norio.

    1988-10-01

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 1 involve structural property data and data processing computer program. (author)

  17. Bacterial community composition and structure in an Urban River impacted by different pollutant sources.

    Science.gov (United States)

    Ibekwe, A Mark; Ma, Jincai; Murinda, Shelton E

    2016-10-01

    Microbial communities in terrestrial fresh water are diverse and dynamic in composition due to different environmental factors. The goal of this study was to undertake a comprehensive analysis of bacterial composition along different rivers and creeks and correlate these to land-use practices and pollutant sources. Here we used 454 pyrosequencing to determine the total bacterial community composition, and bacterial communities that are potentially of fecal origin, and of relevance to water quality assessment. The results were analyzed using UniFrac coupled with principal coordinate analysis (PCoA) to compare diversity, abundance, and community composition. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to correlate bacterial composition in streams and creeks to different environmental parameters impacting bacterial communities in the sediment and surface water within the watershed. Bacteria were dominated by the phyla Proteobacteria, Bacteroidetes, Acidobacteria, and Actinobacteria, with Bacteroidetes significantly (PPCoA and DCA showed that bacterial composition in sediment and surface water was significantly different (Pmicrobial community compositions were influenced by several environmental factors, and pH, NO2, and NH4 were the major environmental factors driving FIB in surface water based on CCA analysis, while NO3 was the only factor in sediment. Published by Elsevier B.V.

  18. Impact simulation in the gravity regime: Exploring the effects of parent body size and internal structure

    Science.gov (United States)

    Benavidez, P. G.; Durda, D. D.; Enke, B.; Bagatin, A. Campo; Richardson, D. C.; Asphaug, E.; Bottke, W. F.

    2018-04-01

    In this work we extend the systematic investigation of impact outcomes of 100-km-diameter targets started by Durda et al. (2007) and Benavidez et al. (2012) to targets of D = 400 km using the same range of impact conditions and two internal structures: monolithic and rubble-pile. We performed a new set of simulations in the gravity regime for targets of 400 km in diameter using these same internal structures. This provides a large set of 600 simulations performed in a systematic way that permits a thorough analysis of the impact outcomes and evaluation of the main features of the size frequency distribution due mostly to self-gravity. In addition, we use the impact outcomes to attempt to constrain the impact conditions of the asteroid belt where known asteroid families with a large expected parent body were formed. We have found fairly good matches for the Eunomia and Hygiea families. In addition, we identified a potential acceptable match to the Vesta family from a monolithic parent body of 468 km. The impact conditions of the best matches suggest that these families were formed in a dynamically excited belt. The results also suggest that the parent body of the Eunomia family could be a monolithic body of 382 km diameter, while the one for Hygiea could have a rubble-pile internal structure of 416 km diameter.

  19. Low-Cost Impact Detection and Location for Automated Inspections of 3D Metallic Based Structures

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2015-05-01

    Full Text Available This paper describes a new low-cost means to detect and locate mechanical impacts (collisions on a 3D metal-based structure. We employ the simple and reasonably hypothesis that the use of a homogeneous material will allow certain details of the impact to be automatically determined by measuring the time delays of acoustic wave propagation throughout the 3D structure. The location of strategic piezoelectric sensors on the structure and an electronic-computerized system has allowed us to determine the instant and position at which the impact is produced. The proposed automatic system allows us to fully integrate impact point detection and the task of inspecting the point or zone at which this impact occurs. What is more, the proposed method can be easily integrated into a robot-based inspection system capable of moving over 3D metallic structures, thus avoiding (or minimizing the need for direct human intervention. Experimental results are provided to show the effectiveness of the proposed approach.

  20. The Impact of Organizational Structure on Internal and External Integration: An empirical, cross-regional assessment

    Directory of Open Access Journals (Sweden)

    Xenophon Koufteros

    2014-06-01

    Full Text Available We examine the effects of organizational structure on cross-functional integration, supplier integration, and customer integration and assess whether such effects vary by geographical region. Specifically, we investigate the impact of centralization, formalization, and complexity on both internal (cross-functional and external (supplier, customer integration. Relationships are examined across Western and East Asian environments using data collected from 238 manufacturing plants in eight countries. We find that structural features have differing impacts on cross-functional, supplier, and customer integration, and these effects vary across geographical regions.

  1. Advances in the analysis of NPP and other critical structures subjected to aircraft impact

    International Nuclear Information System (INIS)

    Riera, Jorge

    2013-01-01

    A brief overview of analysis and design criteria of structures subjected to aircraft impact was presented, focusing attention on factors considered of relevance for NPP design. One of these factors is related to model uncertainty, i.e. to the degree of belief of the designer in the numerical or analytical model employed to determine the structural response. Note that uncertainty grows as we approach the limits of past experience, region in which the analyst and design engineer find themselves when assessing the effects of aircraft impact

  2. Soft impact testing of a wall-floor-wall reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Vepsä, Ari, E-mail: ari.vepsa@vtt.fi; Calonius, Kim; Saarenheimo, Arja; Aatola, Seppo; Halonen, Matti

    2017-01-15

    Highlights: • A wall-floor-wall reinforced concrete structure was built. • The structure was subjected to three almost identical soft impact tests. • Response was measured with accelerometers, displacement sensors and strain gauges. • Modal tests was also carried out with the same structure in different conditions. • The results are meant to be used for validation of computational methods and models. - Abstract: Assessing the safety of the reactor building of a nuclear power plant against the crash of an airplane calls for valid computational tools such as finite element models and material constitutive models. Validation of such tools and models in turn calls for reliable and relevant experimental data. The problem is that such data is scarcely available. One of the aspects of such a crash is vibrations that are generated by the impact. These vibrations tend to propagate from the impact point to the internal parts of the building. If strong enough, these vibrations may cause malfunction of the safety-critical equipment inside the building. To enable validation of computational models for this type of behaviour, we have conducted a series of three tests with a wall-floor-wall reinforced concrete structure under soft impact loading. The response of the structure was measured with accelerometers, displacement sensors and strain gauges. In addition to impact tests, the structure was subjected to modal tests under different conditions. The tests yielded a wealth of useful data for validation of computational models and better understanding about shock induced vibration physics especially in reinforced concrete structures.

  3. On impact damage detection and quantification for CFRP laminates using structural response data only

    Science.gov (United States)

    Sultan, M. T. H.; Worden, K.; Pierce, S. G.; Hickey, D.; Staszewski, W. J.; Dulieu-Barton, J. M.; Hodzic, A.

    2011-11-01

    The overall purpose of the research is to detect and attempt to quantify impact damage in structures made from composite materials. A study that uses simplified coupon specimens made from a Carbon Fibre-Reinforced Polymer (CFRP) prepreg with 11, 12 and 13 plies is presented. PZT sensors were placed at three separate locations in each test specimen to record the responses from impact events. To perform damaging impact tests, an instrumented drop-test machine was used and the impact energy was set to cover a range of 0.37-41.72 J. The response signals captured from each sensor were recorded by a data acquisition system for subsequent evaluation. The impacted specimens were examined with an X-ray technique to determine the extent of the damaged areas and it was found that the apparent damaged area grew monotonically with impact energy. A number of simple univariate and multivariate features were extracted from the sensor signals recorded during impact by computing their spectra and calculating frequency centroids. The concept of discordancy from the statistical discipline of outlier analysis is employed in order to separate the responses from non-damaging and damaging impacts. The results show that the potential damage indices introduced here provide a means of identifying damaging impacts from the response data alone.

  4. Parameter studies to determine sensitivity of slug impact loads to properties of core surrounding structures

    International Nuclear Information System (INIS)

    Gvildys, J.

    1985-01-01

    A sensitivity study of the HCDA slug impact response of fast reactor primary containment to properties of core surrounding structures was performed. Parameters such as the strength of the radial shield material, mass, void, and compressibility properties of the gas plenum material, mass of core material, and mass and compressibility properties of the coolant were used as variables to determine the magnitude of the slug impact loads. The response of the reactor primary containment and the partition of energy were also given. A study was also performed using water as coolant to study the difference in slug impact loads

  5. Spatial vision in Bombus terrestris

    Directory of Open Access Journals (Sweden)

    Aravin eChakravarthi

    2016-02-01

    Full Text Available Bombus terrestris is one of the most commonly used insect models to investigate visually guided behavior and spatial vision in particular. Two fundamental measures of spatial vision are spatial resolution and contrast sensitivity. In this study, we report the threshold of spatial resolution in B. terrestris and characterize the contrast sensitivity function of the bumblebee visual system for a dual choice discrimination task. We trained bumblebees in a Y-maze experimental set-up to associate a vertical sinusoidal grating with a sucrose reward, and a horizontal grating with absence of a reward. Using a logistic psychometric function, we estimated a resolution threshold of 0.21 cycles deg-1 of visual angle. This resolution is in the same range but slightly lower than that found in honeybees (Apis mellifera and A. cerana and another bumblebee species (B. impatiens. We also found that the contrast sensitivity of B. terrestris was 1.57 for the spatial frequency 0.09 cycles deg-1 and 1.26. for 0.18 cycles deg-1.

  6. Impact localization on composite structures using time difference and MUSIC approach

    Science.gov (United States)

    Zhong, Yongteng; Xiang, Jiawei

    2017-05-01

    1-D uniform linear array (ULA) has the shortcoming of the half-plane mirror effect, which does not allow discriminating between a target placed above the array and a target placed below the array. This paper presents time difference (TD) and multiple signal classification (MUSIC) based omni-directional impact localization on a large stiffened composite structure using improved linear array, which is able to perform omni-directional 360° localization. This array contains 2M+3 PZT sensors, where 2M+1 PZT sensors are arranged as a uniform linear array, and the other two PZT sensors are placed above and below the array. Firstly, the arrival times of impact signals observed by the other two sensors are determined using the wavelet transform. Compared with each other, the direction range of impact source can be decided in general, 0°to 180° or 180°to 360°. And then, two dimensional multiple signal classification (2D-MUSIC) based spatial spectrum formula using the uniform linear array is applied for impact localization by the general direction range. When the arrival times of impact signals observed by upper PZT is equal to that of lower PZT, the direction can be located in x axis (0°or 180°). And time difference based MUSIC method is present to locate impact position. To verify the proposed approach, the proposed approach is applied to a composite structure. The localization results are in good agreement with the actual impact occurring positions.

  7. The capital structure impact on forming company’s accounting policy

    OpenAIRE

    Česnavičiūtė, Giedrė

    2011-01-01

    KEWORDS: Accounting policy, accounting policy choice, disclosure of accounting policies, capital structure, financial leverage, legitimacy theory, agency theory, signal theory, stakeholder theory. The optimal structure of the capital has a huge impact assuring its goals and financial stability. The company’s appropriate situation of financial condition depends on the accounting policies formation as well. In this paper there was made the investigation of correlation of company’s capital struc...

  8. Using structural sustainability for forest health monitoring and triage: Case study of a mountain pine beetle (Dendroctonusponderosae)-impacted landscape

    Science.gov (United States)

    Jonathan A. Cale; Jennifer G. Klutsch; Nadir Erbilgin; Jose F. Negron; John D. Castello

    2016-01-01

    Heavy disturbance-induced mortality can negatively impact forest biota, functions, and services by drastically altering the forest structures that create stable environmental conditions. Disturbance impacts on forest structure can be assessed using structural sustainability - the degree of balance between living and dead portions of a tree population’s size-...

  9. Quantification of the impact of PSI:Biology according to the annotations of the determined structures.

    Science.gov (United States)

    DePietro, Paul J; Julfayev, Elchin S; McLaughlin, William A

    2013-10-21

    Protein Structure Initiative:Biology (PSI:Biology) is the third phase of PSI where protein structures are determined in high-throughput to characterize their biological functions. The transition to the third phase entailed the formation of PSI:Biology Partnerships which are composed of structural genomics centers and biomedical science laboratories. We present a method to examine the impact of protein structures determined under the auspices of PSI:Biology by measuring their rates of annotations. The mean numbers of annotations per structure and per residue are examined. These are designed to provide measures of the amount of structure to function connections that can be leveraged from each structure. One result is that PSI:Biology structures are found to have a higher rate of annotations than structures determined during the first two phases of PSI. A second result is that the subset of PSI:Biology structures determined through PSI:Biology Partnerships have a higher rate of annotations than those determined exclusive of those partnerships. Both results hold when the annotation rates are examined either at the level of the entire protein or for annotations that are known to fall at specific residues within the portion of the protein that has a determined structure. We conclude that PSI:Biology determines structures that are estimated to have a higher degree of biomedical interest than those determined during the first two phases of PSI based on a broad array of biomedical annotations. For the PSI:Biology Partnerships, we see that there is an associated added value that represents part of the progress toward the goals of PSI:Biology. We interpret the added value to mean that team-based structural biology projects that utilize the expertise and technologies of structural genomics centers together with biological laboratories in the community are conducted in a synergistic manner. We show that the annotation rates can be used in conjunction with established metrics, i

  10. Research on the Impact of Ownership Structure to Operation Performance of the Chinese Listed Port Companies

    Directory of Open Access Journals (Sweden)

    Bao Jiang

    2015-06-01

    Full Text Available The ownership structure which has a huge impact on company operation performance is the foundation of corporate governance structure choice. At present, the number of China's listed port companies is the largest in the world; however, they have a very complex ownership structure. This study discusses the impact of ownership structure on the operation performance of the Chinese ports. This empirical research applies factor analysis to evaluate the operation performance of listed port companies, and then adopts linear regression analysis based on the evaluation results to explore the impact of ownership structure to operation performance. Finally, it proposes recommendations for optimizing the ownership structure of listed port companies, in order to promote a better and faster development of China's port industry. The empirical results show that for most of the listed port companies, the largest shareholder is in the absolute controlling position, and the gap between the largest shareholder and the second largest shareholder is very large, which means the ownership concentration is relatively high. Meanwhile, the top five shareholders equity ratio squared is in negative correlation with operation performance.

  11. An adjoint method of sensitivity analysis for residual vibrations of structures subject to impacts

    Science.gov (United States)

    Yan, Kun; Cheng, Gengdong

    2018-03-01

    For structures subject to impact loads, the residual vibration reduction is more and more important as the machines become faster and lighter. An efficient sensitivity analysis of residual vibration with respect to structural or operational parameters is indispensable for using a gradient based optimization algorithm, which reduces the residual vibration in either active or passive way. In this paper, an integrated quadratic performance index is used as the measure of the residual vibration, since it globally measures the residual vibration response and its calculation can be simplified greatly with Lyapunov equation. Several sensitivity analysis approaches for performance index were developed based on the assumption that the initial excitations of residual vibration were given and independent of structural design. Since the resulting excitations by the impact load often depend on structural design, this paper aims to propose a new efficient sensitivity analysis method for residual vibration of structures subject to impacts to consider the dependence. The new method is developed by combining two existing methods and using adjoint variable approach. Three numerical examples are carried out and demonstrate the accuracy of the proposed method. The numerical results show that the dependence of initial excitations on structural design variables may strongly affects the accuracy of sensitivities.

  12. Weathering of post-impact hydrothermal deposits from the Haughton impact structure: implications for microbial colonization and biosignature preservation.

    Science.gov (United States)

    Izawa, M R M; Banerjee, Neil R; Osinski, G R; Flemming, R L; Parnell, J; Cockell, C S

    2011-01-01

    Meteorite impacts are among the very few processes common to all planetary bodies with solid surfaces. Among the effects of impact on water-bearing targets is the formation of post-impact hydrothermal systems and associated mineral deposits. The Haughton impact structure (Devon Island, Nunavut, Canada, 75.2 °N, 89.5 °W) hosts a variety of hydrothermal mineral deposits that preserve assemblages of primary hydrothermal minerals commonly associated with secondary oxidative/hydrous weathering products. Hydrothermal mineral deposits at Haughton include intra-breccia calcite-marcasite vugs, small intra-breccia calcite or quartz vugs, intra-breccia gypsum megacryst vugs, hydrothermal pipe structures and associated surface "gossans," banded Fe-oxyhydroxide deposits, and calcite and quartz veins and coatings in shattered target rocks. Of particular importance are sulfide-rich deposits and their associated assemblage of weathering products. Hydrothermal mineral assemblages were characterized structurally, texturally, and geochemically with X-ray diffraction, micro X-ray diffraction, optical and electron microscopy, and inductively coupled plasma atomic emission spectroscopy. Primary sulfides (marcasite and pyrite) are commonly associated with alteration minerals, including jarosite (K,Na,H(3)O)Fe(3)(SO(4))(2)(OH)(6), rozenite FeSO(4)·4(H(2)O), copiapite (Fe,Mg)Fe(4)(SO(4))(6)(OH)(2)·20(H(2)O), fibroferrite Fe(SO(4))(OH)·5(H(2)O), melanterite FeSO(4)·7(H(2)O), szomolnokite FeSO(4)·H(2)O, goethite α-FeO(OH), lepidocrocite γ-FeO(OH) and ferrihydrite Fe(2)O(3)·0.5(H(2)O). These alteration assemblages are consistent with geochemical conditions that were locally very different from the predominantly circumneutral, carbonate-buffered environment at Haughton. Mineral assemblages associated with primary hydrothermal activity, and the weathering products of such deposits, provide constraints on possible microbial activity in the post-impact environment. The initial period of

  13. The impacts of source structure on geodetic parameters demonstrated by the radio source 3C371

    Science.gov (United States)

    Xu, Ming H.; Heinkelmann, Robert; Anderson, James M.; Mora-Diaz, Julian; Karbon, Maria; Schuh, Harald; Wang, Guang L.

    2017-07-01

    Closure quantities measured by very-long-baseline interferometry (VLBI) observations are independent of instrumental and propagation instabilities and antenna gain factors, but are sensitive to source structure. A new method is proposed to calculate a structure index based on the median values of closure quantities rather than the brightness distribution of a source. The results are comparable to structure indices based on imaging observations at other epochs and demonstrate the flexibility of deriving structure indices from exactly the same observations as used for geodetic analysis and without imaging analysis. A three-component model for the structure of source 3C371 is developed by model-fitting closure phases. It provides a real case of tracing how the structure effect identified by closure phases in the same observations as the delay observables affects the geodetic analysis, and investigating which geodetic parameters are corrupted to what extent by the structure effect. Using the resulting structure correction based on the three-component model of source 3C371, two solutions, with and without correcting the structure effect, are made. With corrections, the overall rms of this source is reduced by 1 ps, and the impacts of the structure effect introduced by this single source are up to 1.4 mm on station positions and up to 4.4 microarcseconds on Earth orientation parameters. This study is considered as a starting point for handling the source structure effect on geodetic VLBI from geodetic sessions themselves.

  14. Measurement of deforming mode of lattice truss structures under impact loading

    Directory of Open Access Journals (Sweden)

    Zhao H.

    2012-08-01

    Full Text Available Lattice truss structures, which are used as a core material in sandwich panels, were widely investigated experimentally and theoretically. However, explanation of the deforming mechanism using reliable experimental results is almost rarely reported, particularly for the dynamic deforming mechanism. The present work aimed at the measurement of the deforming mode of lattice truss structures. Indeed, quasi-static and Split Hopkinson Pressure Bar (SHPB tests have been performed on the tetrahedral truss cores structures made of Aluminum 3003-O. Global values such as crushing forces and displacements between the loading platens are obtained. However, in order to understand the deforming mechanism and to explain the observed impact strength enhancement observed in the experiments, images of the truss core element during the tests are recorded. A method based on the edge detection algorithm is developed and applied to these images. The deforming profiles of one beam are extracted and it allows for calculating the length of beam. It is found that these lengths diminish to a critical value (due to compression and remain constant afterwards (because of significant bending. The comparison between quasi-static and impact tests shows that the beam were much more compressed under impact loading, which could be understood as the lateral inertia effect in dynamic bucking. Therefore, the impact strength enhancement of tetrahedral truss core sandwich panel can be explained by the delayed buckling of beam under impact (more compression reached, together with the strain hardening of base material.

  15. Adopting Continuous Delivery and Deployment: Impacts on Team Structures, Collaboration and Responsibilities

    DEFF Research Database (Denmark)

    Shahin, Mojtaba; Zahedi, Mansooreh; Babar, Muhammad Ali

    2017-01-01

    Context: Continuous Delivery and Deployment (CD) practices aim to deliver software features more frequently and reliably. While some efforts have been made to study different aspects of CD practices, a little empirical work has been reported on the impact of CD on team structures, collaboration a...

  16. Using dye tracer for visualizing roots impact on soil structure and soil porous system

    Czech Academy of Sciences Publication Activity Database

    Kodešová, R.; Němeček, K.; Žigová, Anna; Nikodem, A.; Fér, M.

    2015-01-01

    Roč. 70, č. 11 (2015), s. 1439-1443 ISSN 0006-3088 R&D Projects: GA ČR GA526/08/0434 Institutional support: RVO:67985831 Keywords : field sections * macro-scale * micro-scale, * micromorphological images * plant * ponding dye infiltration * roots * soil structure Subject RIV: DF - Soil Science Impact factor: 0.719, year: 2015

  17. Studying Impact of Different Precipitating Agents on Crystal Structure, Morphology and Photocatalytic Activity of Bismuth Oxide

    Directory of Open Access Journals (Sweden)

    Yayuk Astuti

    2017-10-01

    How to Cite: Astuti, Y., Arnelli, Pardoyo, Fauziyah, A., Nurhayati, S., Wulansari, A.D., Andianingrum, R., Widiyandari, H., Bhaduri, G.A. (2017. Studying Impact of Different Precipitating Agents on Crystal Structure, Morphology and Photocatalytic Activity of Bismuth Oxide. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3: 478-484 (doi:10.9767/bcrec.12.3.1144.478-484

  18. Highly Shocked Low Density Sedimentary Rocks from the Haughton Impact Structure, Devon Island, Nunavut, Canada

    Science.gov (United States)

    Osinski, G. R.; Spray, J. G.

    2001-01-01

    We present the preliminary results of a detailed investigation of the shock effects in highly shocked, low density sedimentary rocks from the Haughton impact structure. We suggest that some textural features can be explained by carbonate-silicate immiscibility. Additional information is contained in the original extended abstract.

  19. Vulnerability of the global terrestrial ecosystems to climate change.

    Science.gov (United States)

    Li, Delong; Wu, Shuyao; Liu, Laibao; Zhang, Yatong; Li, Shuangcheng

    2018-05-27

    Climate change has far-reaching impacts on ecosystems. Recent attempts to quantify such impacts focus on measuring exposure to climate change but largely ignore ecosystem resistance and resilience, which may also affect the vulnerability outcomes. In this study, the relative vulnerability of global terrestrial ecosystems to short-term climate variability was assessed by simultaneously integrating exposure, sensitivity, and resilience at a high spatial resolution (0.05°). The results show that vulnerable areas are currently distributed primarily in plains. Responses to climate change vary among ecosystems and deserts and xeric shrublands are the most vulnerable biomes. Global vulnerability patterns are determined largely by exposure, while ecosystem sensitivity and resilience may exacerbate or alleviate external climate pressures at local scales; there is a highly significant negative correlation between exposure and sensitivity. Globally, 61.31% of the terrestrial vegetated area is capable of mitigating climate change impacts and those areas are concentrated in polar regions, boreal forests, tropical rainforests, and intact forests. Under current sensitivity and resilience conditions, vulnerable areas are projected to develop in high Northern Hemisphere latitudes in the future. The results suggest that integrating all three aspects of vulnerability (exposure, sensitivity, and resilience) may offer more comprehensive and spatially explicit adaptation strategies to reduce the impacts of climate change on terrestrial ecosystems. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Impact damage response of natural stitched single lap-joint in composite structures

    International Nuclear Information System (INIS)

    Ghasemnejad, H.; Argentiero, Y.; Tez, T.A.; Barrington, P.E.

    2013-01-01

    Highlights: • To study the impact resistance of single lap-joints in composite structures. • To improve the impact resistance of stitched single lap joints using natural Flax yarn. • To investigate the effect of stitching on the damage process of composite materials. • To develop FE techniques to model the impact process of composite structures using LSDYNA. - Abstract: In this paper the damage behaviour of natural stitched composite single lap-joints are investigated under low velocity impact loading conditions. For this study, the laminated hybrid composite beams were pinned using Flax yarns before curing process. The Charpy impact test was chosen to study the energy absorbing capability of single lap composite joints. Composite beams were fabricated from combination of glass/epoxy and carbon/epoxy composites. It was shown that composite beams which are stitched through the thickness are able to absorb more energy in comparison with adhesive bonded composite joints in the hybrid composite beams. The Charpy impact test of stitched composite single lap joint was also simulated by finite element analysis using software LS-DYNA and the results verified with relevant experimental data

  1. Elements of the Chicxulub Impact Structure as Revealed in SRTM and Surface GPS Topographic Data

    Science.gov (United States)

    Kinsland, Gary L.; Sanchez, Gary; Kobrick, Michael; Cardador, Manuel Hurtado

    2003-01-01

    Pope et al. [1] utilized the elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxulub Impact Structure is a roughly semi-circular, lowrelief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact, which possibly led to the development of these features. These are summarized in Table 1. Kinsland et al. [2] presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Very recently we have acquired digital topography data from NASA s Shuttle Radar Topography Mission (SRTM). Our subset covers 6 square degrees from 20deg N 91degW to 22deg N 88degW (corner to corner) with a pixel size of about 90m. This area includes all of the identified portion of the crater on land.

  2. Unbalanced voltage faults: the impact on structural loads of doubly fed asynchronous generator wind turbines

    DEFF Research Database (Denmark)

    Barahona Garzón, Braulio; Cutululis, Nicolaos Antonio; Hansen, Anca Daniela

    2014-01-01

    This paper investigates the impact that unbalanced voltage faults have on wind turbine structural loads. In such cases, electromagnetic torque oscillations occur at two times the supply voltage frequency. The objectives of this work are to quantify wind turbine structural loads induced...... by unbalanced voltage faults relative to those during normal operation; and to evaluate the potential for reducing structural loads with the control of the generator. The method applied is integrated dynamic analysis. Namely, dynamic analysis with models that consider the most important aeroelastic, electrical...

  3. Structural Changes of International Trade Flows under the Impact of Globalization

    Directory of Open Access Journals (Sweden)

    Anca Dachin

    2006-08-01

    Full Text Available Structural changes of international trade flows indicate modifications in competitiveness of countries, in terms of production, technological upgrading and exports under the pressure of globalization. The paper aims to point out sources of competitive advantages especially in manufacturing exports of different groups of countries. The focus is on the shifts in the structure of manufacturing in the European Union and their effects on international rankings in export performances. An important issue refers to the opportunities given by the enlargement of the European Union and their impact on EU trade structures.

  4. The Impact of Tariff Structure on Customer Retention, Usage, and Profitability of Access Services

    OpenAIRE

    Raghuram Iyengar; Kamel Jedidi; Skander Essegaier; Peter J. Danaher

    2011-01-01

    Past research in marketing and psychology suggests that pricing structure may influence consumers' perception of value. In the context of two commonly used pricing schemes, pay-per-use and two-part tariff, we evaluate the impact of pricing structure on consumer preferences for access services. To this end, we develop a utility-based model of consumer retention and usage of a new service. A notable feature of the model is its ability to capture the pricing structure effect and measure its impa...

  5. Improved structural integrity through advances in reliable residual stress measurement: the impact of ENGIN-X

    Science.gov (United States)

    Edwards, L.; Santisteban, J. R.

    The determination of accurate reliable residual stresses is critical to many fields of structural integrity. Neutron stress measurement is a non-destructive technique that uniquely provides insights into stress fields deep within engineering components and structures. As such, it has become an increasingly important tool within engineering, leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise lifing procedures. This paper describes the likely impact of the next generation of dedicated engineering stress diffractometers currently being constructed and the utility of the technique using examples of residual stresses both beneficial and detrimental to structural integrity.

  6. Major decline in marine and terrestrial animal consumption by brown bears (Ursus arctos).

    Science.gov (United States)

    Matsubayashi, Jun; Morimoto, Junko O; Tayasu, Ichiro; Mano, Tsutomu; Nakajima, Miyuki; Takahashi, Osamu; Kobayashi, Kyoko; Nakamura, Futoshi

    2015-03-17

    Human activities have had the strongest impacts on natural ecosystems since the last glacial period, including the alteration of interspecific relationships such as food webs. In this paper, we present a historical record of major alterations of trophic structure by revealing millennium-scale dietary shifts of brown bears (Ursus arctos) on the Hokkaido islands, Japan, using carbon, nitrogen, and sulfur stable isotope analysis. Dietary analysis of brown bears revealed that salmon consumption by bears in the eastern region of Hokkaido significantly decreased from 19% to 8%. In addition, consumption of terrestrial animals decreased from 56% to 5% in western region, and 64% to 8% in eastern region. These dietary shifts are likely to have occurred in the last approximately 100-200 years, which coincides with the beginning of modernisation in this region. Our results suggest that human activities have caused an alteration in the trophic structure of brown bears in the Hokkaido islands. This alteration includes a major decline in the marine-terrestrial linkage in eastern region, and a loss of indirect-interactions between bears and wolves, because the interactions potentially enhanced deer predation by brown bears.

  7. Nonlinear Waves in the Terrestrial Quasiparallel Foreshock.

    Science.gov (United States)

    Hnat, B; Kolotkov, D Y; O'Connell, D; Nakariakov, V M; Rowlands, G

    2016-12-02

    We provide strongly conclusive evidence that the cubic nonlinearity plays an important part in the evolution of the large amplitude magnetic structures in the terrestrial foreshock. Large amplitude nonlinear wave trains at frequencies above the proton cyclotron frequency are identified after nonharmonic slow variations are filtered out by applying the empirical mode decomposition. Numerical solutions of the derivative nonlinear Schrödinger equation, predicted analytically by the use of a pseudopotential approach, are found to be consistent with the observed wave forms. The approximate phase speed of these nonlinear waves, indicated by the parameters of numerical solutions, is of the order of the local Alfvén speed. We suggest that the feedback of the large amplitude fluctuations on background plasma is reflected in the evolution of the pseudopotential.

  8. New steroidal glycosides from Tribulus terrestris L.

    Science.gov (United States)

    Chen, Gang; Liu, Tao; Lu, Xuan; Wang, Hai-Feng; Hua, Hui-Ming; Pei, Yue-Hu

    2012-01-01

    Two new steroidal glycosides were isolated from Tribulus terrestris L. Their structures were elucidated as 26-O-β-D-glucopyranosyl-5α-furostan-12-one-20(22)-ene-3β,23,26-triol-3-O-β-D-xylopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 4)-[α-L-rhamnopyranosyl-(1 → 2)]-β-D-galactopyranoside (1) and 26-O-β-D-glucopyranosyl-5α-furostan-20(22)-ene-3β,23,26-triol-3-O-β-D-xylopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 4)-[α-L-rhamnopyranosyl-(1 → 2)]-β-D-galactopyranoside (2) by spectroscopic methods including 1D and 2D NMR experiments.

  9. Coexistence of Terrestrial and HAP 3G Networks during Disaster Scenarios

    Directory of Open Access Journals (Sweden)

    P. Pechac

    2008-12-01

    Full Text Available The aim of this paper is to show the possible coexistence of an HAP and a terrestrial component of 3G networks at a single carrier frequency. The main goal is to compare the basic parameters of terrestrial and HAP com-ponent 3G networks modeled in suburban (macrocell and urban (macro/microcell areas and to demonstrate the way they impact on each other. This study should present what we assume are the better capabilities of HAP 3G networks compared to their terrestrial counterparts. The parameters of the HAP and terrestrial component of 3G networks, were the terrestrial cells to be disabled during disasters, are also presented.

  10. Planetary Structures And Simulations Of Large-scale Impacts On Mars

    Science.gov (United States)

    Swift, Damian; El-Dasher, B.

    2009-09-01

    The impact of large meteroids is a possible cause for isolated orogeny on bodies devoid of tectonic activity. On Mars, there is a significant, but not perfect, correlation between large, isolated volcanoes and antipodal impact craters. On Mercury and the Moon, brecciated terrain and other unusual surface features can be found at the antipodes of large impact sites. On Earth, there is a moderate correlation between long-lived mantle hotspots at opposite sides of the planet, with meteoroid impact suggested as a possible cause. If induced by impacts, the mechanisms of orogeny and volcanism thus appear to vary between these bodies, presumably because of differences in internal structure. Continuum mechanics (hydrocode) simulations have been used to investigate the response of planetary bodies to impacts, requiring assumptions about the structure of the body: its composition and temperature profile, and the constitutive properties (equation of state, strength, viscosity) of the components. We are able to predict theoretically and test experimentally the constitutive properties of matter under planetary conditions, with reasonable accuracy. To provide a reference series of simulations, we have constructed self-consistent planetary structures using simplified compositions (Fe core and basalt-like mantle), which turn out to agree surprisingly well with the moments of inertia. We have performed simulations of large-scale impacts, studying the transmission of energy to the antipodes. For Mars, significant antipodal heating to depths of a few tens of kilometers was predicted from compression waves transmitted through the mantle. Such heating is a mechanism for volcanism on Mars, possibly in conjunction with crustal cracking induced by surface waves. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Impact of environmental inputs on reverse-engineering approach to network structures.

    Science.gov (United States)

    Wu, Jianhua; Sinfield, James L; Buchanan-Wollaston, Vicky; Feng, Jianfeng

    2009-12-04

    Uncovering complex network structures from a biological system is one of the main topic in system biology. The network structures can be inferred by the dynamical Bayesian network or Granger causality, but neither techniques have seriously taken into account the impact of environmental inputs. With considerations of natural rhythmic dynamics of biological data, we propose a system biology approach to reveal the impact of environmental inputs on network structures. We first represent the environmental inputs by a harmonic oscillator and combine them with Granger causality to identify environmental inputs and then uncover the causal network structures. We also generalize it to multiple harmonic oscillators to represent various exogenous influences. This system approach is extensively tested with toy models and successfully applied to a real biological network of microarray data of the flowering genes of the model plant Arabidopsis Thaliana. The aim is to identify those genes that are directly affected by the presence of the sunlight and uncover the interactive network structures associating with flowering metabolism. We demonstrate that environmental inputs are crucial for correctly inferring network structures. Harmonic causal method is proved to be a powerful technique to detect environment inputs and uncover network structures, especially when the biological data exhibit periodic oscillations.

  12. On the structural behavior of ship's shell structures due to impact loading

    Directory of Open Access Journals (Sweden)

    Hyung Kyun Lim

    2018-01-01

    Full Text Available When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper–Symonds model and Johnson–Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

  13. The thermal impact of subsurface building structures on urban groundwater resources - A paradigmatic example.

    Science.gov (United States)

    Epting, Jannis; Scheidler, Stefan; Affolter, Annette; Borer, Paul; Mueller, Matthias H; Egli, Lukas; García-Gil, Alejandro; Huggenberger, Peter

    2017-10-15

    Shallow subsurface thermal regimes in urban areas are increasingly impacted by anthropogenic activities, which include infrastructure development like underground traffic lines as well as industrial and residential subsurface buildings. In combination with the progressive use of shallow geothermal energy systems, this results in the so-called subsurface urban heat island effect. This article emphasizes the importance of considering the thermal impact of subsurface structures, which commonly is underestimated due to missing information and of reliable subsurface temperature data. Based on synthetic heat-transport models different settings of the urban environment were investigated, including: (1) hydraulic gradients and conductivities, which result in different groundwater flow velocities; (2) aquifer properties like groundwater thickness to aquitard and depth to water table; and (3) constructional features, such as building depths and thermal properties of building structures. Our results demonstrate that with rising groundwater flow velocities, the heat-load from building structures increase, whereas down-gradient groundwater temperatures decrease. Thermal impacts on subsurface resources therefore have to be related to the permeability of aquifers and hydraulic boundary conditions. In regard to the urban settings of Basel, Switzerland, flow velocities of around 1 md -1 delineate a marker where either down-gradient temperature deviations or heat-loads into the subsurface are more relevant. Furthermore, no direct thermal influence on groundwater resources should be expected for aquifers with groundwater thicknesses larger 10m and when the distance of the building structure to the groundwater table is higher than around 10m. We demonstrate that measuring temperature changes down-gradient of subsurface structures is insufficient overall to assess thermal impacts, particularly in urban areas. Moreover, in areas which are densely urbanized, and where groundwater flow

  14. The impact of sample size and marker selection on the study of haplotype structures

    Directory of Open Access Journals (Sweden)

    Sun Xiao

    2004-03-01

    Full Text Available Abstract Several studies of haplotype structures in the human genome in various populations have found that the human chromosomes are structured such that each chromosome can be divided into many blocks, within which there is limited haplotype diversity. In addition, only a few genetic markers in a putative block are needed to capture most of the diversity within a block. There has been no systematic empirical study of the effects of sample size and marker set on the identified block structures and representative marker sets, however. The purpose of this study was to conduct a detailed empirical study to examine such impacts. Towards this goal, we have analysed three representative autosomal regions from a large genome-wide study of haplotypes with samples consisting of African-Americans and samples consisting of Japanese and Chinese individuals. For both populations, we have found that the sample size and marker set have significant impact on the number of blocks and the total number of representative markers identified. The marker set in particular has very strong impacts, and our results indicate that the marker density in the original datasets may not be adequate to allow a meaningful characterisation of haplotype structures. In general, we conclude that we need a relatively large sample size and a very dense marker panel in the study of haplotype structures in human populations.

  15. The effects of pressure dependent constitutive model to simulate concrete structures failure under impact loads

    Science.gov (United States)

    Mokhatar, S. N.; Sonoda, Y.; Kamarudin, A. F.; Noh, M. S. Md; Tokumaru, S.

    2018-04-01

    The main objective of this paper is to explore the effect of confining pressure in the compression and tension zone by simulating the behaviour of reinforced concrete/mortar structures subjected to the impact load. The analysis comprises the numerical simulation of the influences of high mass low speed impact weight dropping on concrete structures, where the analyses are incorporated with meshless method namely as Smoothed Particle Hydrodynamics (SPH) method. The derivation of the plastic stiffness matrix of Drucker-Prager (DP) that extended from Von-Mises (VM) yield criteria to simulate the concrete behaviour were presented in this paper. In which, the displacements for concrete/mortar structures are assumed to be infinitesimal. Furthermore, the influence of the different material model of DP and VM that used numerically for concrete and mortar structures are also discussed. Validation upon existing experimental test results is carried out to investigate the effect of confining pressure, it is found that VM criterion causes unreal impact failure (flexural cracking) of concrete structures.

  16. Single-impact calibrated electromagnetic tightening of long-life bolted joints in aviation structures

    Science.gov (United States)

    Firsov, V. A.; Bekhmet'ev, V. I.

    The general design and operation of a newly developed electromagnetic impact driver for the assembly of aviation structures is described. The electromagnetic impact driver makes it possible to considerably improve the precision of bolt torquing during the assembly. To test the performance of the new tool, M6 bolts of 16KhSN steel (tensile strength 120 +/- 10 kg/sq mm) were tightened by a manual torque wrench and by the electromagnetic impact driver. It is shown that the scatter of bolt elongation during the tightening by the impact driver is a factor of 3-5 less than in the case of manual torquing, which corresponds to a torque precision of 1.5-2 percent.

  17. The impact of ownership structure on bank credit risk: Evidence from Bangladesh

    Directory of Open Access Journals (Sweden)

    Niluthpaul SARKER

    2017-05-01

    Full Text Available This study investigates the impact of ownership structure of Commercial Banks on bank credit risk in an emerging market like Bangladesh. Prais Winten regression model is applied to a sample of 32 commercial banks from the year of 2000 to 2014 with 390 observations. The result reveals that National Commercial Banks, depositors’ influence, shareholders’ influence, liquidity and profitability are negatively associated with credit risk whereas lag risk has a significant positive impact on credit risk. The effect of banks ownership structure on credit risk divulges a delicate governance of the banking sector. The study conveys a momentous implication of research findings in the national economy. It also found that national commercial banks have the tendency of violating the rules and absorbing heavy risk. It suggests that policy maker should rethink about the government ownership of banks. Therefore the denationalization or reducing government ownership structure is highly recommended.

  18. The Financial Structure and its Impact on Financial -Economic Results in Cuban Companies

    Directory of Open Access Journals (Sweden)

    María Esperanza González-del-Foyo

    2016-06-01

    Full Text Available The financial structure refers to the way a company finances its assets through a combination of equity, debtor hybrid securities. Financial decisions are important in business management, on which heavily rely the viability and rentability of business. Hence the need for managers to know and analyze the financing structure in order to evaluate the impact on its results from the point of view of risk, cost and performance. In the article the main theories of financial structure are based, and the different approaches for its study. Considerations are made on this issue in the Cuban economy, and techniques are applied to evaluate the impact of financing in the form of risk and performance against the company on the “Cecilio Sanchez Valiente” in Santiago de Cuba.

  19. Simulation of High Velocity Impact on Composite Structures - Model Implementation and Validation

    Science.gov (United States)

    Schueler, Dominik; Toso-Pentecôte, Nathalie; Voggenreiter, Heinz

    2016-08-01

    High velocity impact on composite aircraft structures leads to the formation of flexural waves that can cause severe damage to the structure. Damage and failure can occur within the plies and/or in the resin rich interface layers between adjacent plies. In the present paper a modelling methodology is documented that captures intra- and inter-laminar damage and their interrelations by use of shell element layers representing sub-laminates that are connected with cohesive interface layers to simulate delamination. This approach allows the simulation of large structures while still capturing the governing damage mechanisms and their interactions. The paper describes numerical algorithms for the implementation of a Ladevèze continuum damage model for the ply and methods to derive input parameters for the cohesive zone model. By comparison with experimental results from gas gun impact tests the potential and limitations of the modelling approach are discussed.

  20. Diagnostic tool for structural health monitoring: effect of material nonlinearity and vibro-impact process

    Science.gov (United States)

    Hiwarkar, V. R.; Babitsky, V. I.; Silberschmidt, V. V.

    2013-07-01

    Numerous techniques are available for monitoring structural health. Most of these techniques are expensive and time-consuming. In this paper, vibration-based techniques are explored together with their use as diagnostic tools for structural health monitoring. Finite-element simulations are used to study the effect of material nonlinearity on dynamics of a cracked bar. Additionally, several experiments are performed to study the effect of vibro-impact behavior of crack on its dynamics. It was observed that a change in the natural frequency of the cracked bar due to crack-tip plasticity and vibro-impact behavior linked to interaction of crack faces, obtained from experiments, led to generation of higher harmonics; this can be used as a diagnostic tool for structural health monitoring.

  1. Low-Frequency Acoustic Noise Mitigation Characteristics of Metamaterials-Inspired Vibro-Impact Structures

    Science.gov (United States)

    Rekhy, Anuj

    Acoustic absorbers like foams, fiberglass or liners have been used commonly in structures for infrastructural, industrial, automotive and aerospace applications to mitigate noise. However, these conventional materials have limited effectiveness to mitigate low-frequency (LF) acoustic waves with frequency less than 400 Hz owing to the need for impractically large mass or volume. LF acoustic waves contribute significantly towards environmental noise pollution as well as unwanted structural responses. Therefore, there is a need to develop lightweight, compact, structurally-integrated solutions to mitigate LF noise in several applications. Inspired by metamaterials, which are man-made structural materials that derive their unique dynamic behavior not just from material constituents but more so from engineered configurations, tuned mass-loaded membranes as vibro-impact attachments on a baseline structure are investigated to determine their performance as a LF acoustic barrier. The hypothesis is that the LF incident waves are up-converted via impact to higher modes in the baseline structure which are far more evanescent and may then be effectively mitigated using conventional means. Such Metamaterials-Inspired Vibro-Impact Structures (MIVIS) could be tuned to match the dominant frequency content of LF acoustic sources in specific applications. Prototype MIVIS unit cells were designed and tested to study the energy transfer mechanism via impact-induced frequency up-conversion, and the consequent sound transmission loss. Structural acoustic simulations were done to predict responses using models based on normal incidence transmission loss tests. Experimental proof-of-concept was achieved and further correlations to simulations were utilized to optimize the energy up-conversion mechanism using parametric studies. Up to 36 dB of sound transmission loss increase is obtained at the anti-resonance frequency (326 Hz) within a tunable LF bandwidth of about 200 Hz while impact

  2. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2014-01-01

    Terrestrial water storage (TWS) comprises groundwater, soil moisture, surface water, snow,and ice. Groundwater typically varies more slowly than the other TWS components because itis not in direct contact with the atmosphere, but often it has a larger range of variability onmultiannual timescales (Rodell and Famiglietti, 2001; Alley et al., 2002). In situ groundwaterdata are only archived and made available by a few countries. However, monthly TWSvariations observed by the Gravity Recovery and Climate Experiment (GRACE; Tapley et al.,2004) satellite mission, which launched in 2002, are a reasonable proxy for unconfinedgroundwater at climatic scales.

  3. On the failure behaviour to striking bow penetration of impacted marine-steel structures

    Science.gov (United States)

    Prabowo, Aditya Rio; Muttaqie, Teguh; Sohn, Jung Min; Bae, Dong Myung; Setiyawan, Agus

    2018-04-01

    Demands for water transportation modes are continuously increasing as rapid economic and industrial growths in the recent decade. Ship as representative of the water transportation is generally needed to carry various products from one location to another. Besides as product carrier, ship also acts as public facility to transport human across islands for number of reasons, such as tourism and vehicle. Considering its importance, structural damage due to accidental loads or so-called impact can cause unacceptable casualties which threat ship passenger, shipping industry and maritime environment in same time. The most frequent impact phenomena occur in forms of collision and grounding, which are targeting side structure and double bottom consecutively. However, since responses of the impacts on structure are highly nonlinear and vary due to development of ship structures, sustainable analysis as an update of pioneer calculation can be beneficial as rational reference for improving safety and navigational instruments. This work aims to assess failures of the side structures subjected to penetration of striking bow in ship-ship collision scenario. Locations of impact are idealized to happen on after-end, midsection and fore-end to provide complete assessment. Striking bow is to be deployed by varying input velocity to observe significance of the fractures on the side structure. This configuration is implemented on the designed collision scenario, and later calculated using nonlinear finite element method (NLFEM). Summary of the solution indicated that the midsection produced the highest resistance against side collision. Breaching of the inner shell was successfully avoided on the fore-end, but the critical damage to the cargo was observed during bow penetration to the after-end region. This location was recommended to be added by longitudinal framing to increase its resistance against ship collision.

  4. On the failure behaviour to striking bow penetration of impacted marine-steel structures

    Directory of Open Access Journals (Sweden)

    Prabowo Aditya Rio

    2018-04-01

    Full Text Available Demands for water transportation modes are continuously increasing as rapid economic and industrial growths in the recent decade. Ship as representative of the water transportation is generally needed to carry various products from one location to another. Besides as product carrier, ship also acts as public facility to transport human across islands for number of reasons, such as tourism and vehicle. Considering its importance, structural damage due to accidental loads or so-called impact can cause unacceptable casualties which threat ship passenger, shipping industry and maritime environment in same time. The most frequent impact phenomena occur in forms of collision and grounding, which are targeting side structure and double bottom consecutively. However, since responses of the impacts on structure are highly nonlinear and vary due to development of ship structures, sustainable analysis as an update of pioneer calculation can be beneficial as rational reference for improving safety and navigational instruments. This work aims to assess failures of the side structures subjected to penetration of striking bow in ship-ship collision scenario. Locations of impact are idealized to happen on after-end, midsection and fore-end to provide complete assessment. Striking bow is to be deployed by varying input velocity to observe significance of the fractures on the side structure. This configuration is implemented on the designed collision scenario, and later calculated using nonlinear finite element method (NLFEM. Summary of the solution indicated that the midsection produced the highest resistance against side collision. Breaching of the inner shell was successfully avoided on the fore-end, but the critical damage to the cargo was observed during bow penetration to the after-end region. This location was recommended to be added by longitudinal framing to increase its resistance against ship collision.

  5. Chemical constituents from Tribulus terrestris and screening of their antioxidant activity

    NARCIS (Netherlands)

    Hammoda, Hala M; Ghazy, Nabila M; Harraz, Fathalla M; Radwan, Mohamed M; ElSohly, Mahmoud A; Abdallah, Ingy I

    Two oligosaccharides (1,2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4-8). The structures of the compounds were established as

  6. Pizza or Pancake? Formation Models of Gas Escape Biosignatures in Terrestrial and Martian Sediments

    Science.gov (United States)

    Bonaccorsi, R.; Fairen, A. G.; Baker, L.; McKay, C. P.; Willson, D.

    2016-05-01

    Fine-grained sedimentary hollowed structures were imaged in Gale Crater, but no biomarkers identified to support biology. Our observation-based (gas escape) terrestrial model could inform on possible martian paleoenvironments at time of formation.

  7. Intermittent Astrophysical Radiation Sources and Terrestrial Life

    Science.gov (United States)

    Melott, Adrian

    2013-04-01

    Terrestrial life is exposed to a variety of radiation sources. Astrophysical observations suggest that strong excursions in cosmic ray flux and spectral hardness are expected. Gamma-ray bursts and supernovae are expected to irradiate the atmosphere with keV to GeV photons at irregular intervals. Supernovae will produce large cosmic ray excursions, with time development varying with distance from the event. Large fluxes of keV to MeV protons from the Sun pose a strong threat to electromagnetic technology. The terrestrial record shows cosmogenic isotope excursions which are consistent with major solar proton events, and there are observations of G-stars suggesting that the rate of such events may be much higher than previously assumed. In addition there are unknown and unexplained astronomical transients which may indicate new classes of events. The Sun, supernovae, and gamma-ray bursts are all capable of producing lethal fluences, and some are expected on intervals of 10^8 years or so. The history of life on Earth is filled with mass extinctions at a variety of levels of intensity. Most are not understood. Astrophysical radiation may play a role, particularly from large increases in muon irradiation on the ground, and changes in atmospheric chemistry which deplete ozone, admitting increased solar UVB. UVB is strongly absorbed by DNA and proteins, and breaks the chemical bonds---it is a known carcinogen. High muon fluxes will also be damaging to such molecules, but experiments are needed to pin down the rate. Solar proton events which are not directly dangerous for the biota may nevertheless pose a major threat to modern electromagnetic technology through direct impact on satellites and magnetic induction of large currents in power grids, disabling transformers. We will look at the kind of events that are expected on timescales from human to geological, and their likely consequences.

  8. TERRESTRIAL PLANET FORMATION FROM AN ANNULUS

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Kevin J.; Levison, Harold F., E-mail: kwalsh@boulder.swri.edu [Southwest Research Institute, 1050 Walnut St. Suite 300, Boulder, CO 80302 (United States)

    2016-09-01

    It has been shown that some aspects of the terrestrial planets can be explained, particularly the Earth/Mars mass ratio, when they form from a truncated disk with an outer edge near 1.0 au. This has been previously modeled starting from an intermediate stage of growth utilizing pre-formed planetary embryos. We present simulations that were designed to test this idea by following the growth process from km-sized objects located between 0.7 and 1.0 au up to terrestrial planets. The simulations explore initial conditions where the solids in the disk are planetesimals with radii initially between 3 and 300 km, alternately including effects from a dissipating gaseous solar nebula and collisional fragmentation. We use a new Lagrangian code known as LIPAD, which is a particle-based code that models the fragmentation, accretion, and dynamical evolution of a large number of planetesimals, and can model the entire growth process from km-sizes up to planets. A suite of large (∼ Mars mass) planetary embryos is complete in only ∼1 Myr, containing most of the system mass. A quiescent period then persists for 10–20 Myr characterized by slow diffusion of the orbits and continued accretion of the remaining planetesimals. This is interrupted by an instability that leads to embryos crossing orbits and embryo–embryo impacts that eventually produce the final set of planets. While this evolution is different than that found in other works exploring an annulus, the final planetary systems are similar, with roughly the correct number of planets and good Mars-analogs.

  9. Rain water drop impact as a laboratory methodology to determinate the soils structural stability

    International Nuclear Information System (INIS)

    Arias, Dora M; Amezquita E

    1999-01-01

    To avoid degradation, it is necessary to have (sufficiently) sensitive parameter to the use actions, so that it is possible to determine what negative changes are happening and to take the soil management measures that avoid the degradation. One of the main causes of degradation in the areas of hillside of Colombia is the erosion, which begins with the impact of the drop of rainwater on the bare soil. For this research samples of an oxic dystropepts were taken at two depths (0-2.5 and 2.5-5 cm) to studying the susceptibility of its structure, to the impact of the drop falling from 2000 mm high. The samples were subjected to drop impact, in a special assembly apparatus that generated drops falling on samples that were 2-m below rotating in a rotations apparatus of generation of drops. As the time of impact advanced, the changes in the hydraulic conductivity were determined. This as parameter was used as an indicator appraiser of the structural resistance of the soils. The results show that the used methodology was sensitive to the situations of use of the soils. The initial hydraulic conductivity was higher in the production systems less intervened (natural forest, leucaena, with mulch, without mulch) and smaller in la those ones most intervened (monocrops of corn, bean, yuca), showing that human intervention has promotes a decay in the stability of soil structure

  10. Quantifying the Impacts of Outlet Control Structures on Lake Hydrology and Ecology

    Science.gov (United States)

    Budd, B. M.; Kendall, A. D.; Martin, S. L.; Hyndman, D. W.

    2012-12-01

    There have been limited studies of the impacts of lake level control structures on stream ecology and lake property erosion. We examine the influence of historical lake level management strategies on Higgins Lake in Michigan, which is regionally known for recreation, fisheries, and scenery. Lake control structures have potentially increased shoreline erosion and seasonally-reduced flow through the outlets, likely impacting fish habitat. Concerns over these issues spurred local land owners to seek a study on the possible hydrologic and ecological impacts of the removal or modification of the control structure. Bathymetry maps are fundamental to understanding and managing lake ecosystems. From the 1930's through the 1950's, these maps were developed for thousands of Michigan inland lakes using soundings lowered through holes cut in winter lake ice. Increased land use change and alterations of lake outlets have likely modified erosion and sedimentation rates of these lake systems. Our research includes bathymetry surveys of Higgins Lake using an Acoustic Doppler Current Profiler (ADCP) and side-scan sonar. The new higher-resolution bathymetry serves as the basis for simulating impacts of potential changes in lake management, on a verity of inpoint including shoreline position and fish habitat.

  11. Fluid-structure interaction analysis of the drop impact test for helicopter fuel tank.

    Science.gov (United States)

    Yang, Xianfeng; Zhang, Zhiqiang; Yang, Jialing; Sun, Yuxin

    2016-01-01

    The crashworthiness of helicopter fuel tank is vital to the survivability of the passengers and structures. In order to understand and improve the crashworthiness of the soft fuel tank of helicopter during the crash, this paper investigated the dynamic behavior of the nylon woven fabric composite fuel tank striking on the ground. A fluid-structure interaction finite element model of the fuel tank based on the arbitrary Lagrangian-Eulerian method was constructed to elucidate the dynamic failure behavior. The drop impact tests were conducted to validate the accuracy of the numerical simulation. Good agreement was achieved between the experimental and numerical results of the impact force with the ground. The influences of the impact velocity, the impact angle, the thickness of the fuel tank wall and the volume fraction of water on the dynamic responses of the dropped fuel tank were studied. The results indicated that the corner of the fuel tank is the most vulnerable location during the impact with ground.

  12. Effect of temperature on composite sandwich structures subjected to low velocity impact. [aircraft construction materials

    Science.gov (United States)

    Sharma, A. V.

    1980-01-01

    The effect of low velocity projectile impact on sandwich-type structural components was investigated. The materials used in the fabrication of the impact surface were graphite-, Kevlar-, and boron-fibers with appropriate epoxy matrices. The testing of the specimens was performed at moderately low- and high-temperatures as well as at room temperature to assess the impact-initiated strength degradation of the laminates. Eleven laminates with different stacking sequences, orientations, and thicknesses were tested. The low energy projectile impact is considered to simulate the damage caused by runway debris, the dropping of the hand tools during servicing, etc., on the secondary aircraft structures fabricated with the composite materials. The results show the preload and the impact energy combinations necessary to cause catastrophic failure in the laminates tested. A set of faired curves indicating the failure thresholds is shown separately for the tension-and compression-loaded laminates. The specific-strengths and -modulii for the various laminates tested are also given.

  13. THE IMPACT OF CORPORATE GOVERNANCE DIMENSIONS ON FINANCIAL STRUCTURE OF THE COMPANIES IN DEVELOPING COUNTRIES

    Directory of Open Access Journals (Sweden)

    IONESCU ALIN

    2014-12-01

    Full Text Available Corporate governance represents a current topic for academic community and practitioners, in the context of globalization and crisis, especially in case of developing countries. The main purpose of this paper is to analyze which dimensions of corporate governance are able to exercise a significant impact on the companies’ financial structure, using a dataset with 77 developing countries from Africa, Asia, Latin America and Central and Eastern Europe. The data are provided from World Bank Enterprise Survey website and the variables are grouped in two directions: corporate governance and financial structure variables. In this regard, using principal components analysis approach, we grouped firstly the variables related to financial structure and then variables related to the main four dimensions of corporate governance, such as ownership structure and management quality, transparency, environment and corruption. The impact of corporate governance dimensions on companies’ financial structure was analyzed in a generalized linear model framework and the main result of this paper consists in the fact that, for analyzed countries, companies’ financial structure is significantly influenced by several dimensions of the governance like transparency, environment or corruption

  14. THE IMPACT OF CORPORATE GOVERNANCE DIMENSIONS ON FINANCIAL STRUCTURE OF THE COMPANIES IN DEVELOPING COUNTRIES

    Directory of Open Access Journals (Sweden)

    IONESCU ALIN

    2014-12-01

    Full Text Available Corporate governance represents a current topic for academic community and practitioners, in the context of globalization and crisis, especially in case of developing countries. The main purpose of this paper is to analyze which dimensions of corporate governance are able to exercise a significant impact on the companies’ financial structure, using a dataset with 77 developing countries from Africa, Asia, Latin America and Central and Eastern Europe. The data are provided from World Bank Enterprise Survey website and the variables are grouped in two directions: corporate governance and financial structure variables. In this regard, using principal components analysis approach, we grouped firstly the variables related to financial structure and then variables related to the main four dimensions of corporate governance, such as ownership structure and management quality, transparency, environment and corruption. The impact of corporate governance dimensions on companies’ financial structure was analyzed in a generalized linear model framework and the main result of this paper consists in the fact that, for analyzed countries, companies’ financial structure is significantly influenced by several dimensions of the governance like transparency, environment or corruption.

  15. The impact of category structure and training methodology on learning and generalizing within-category representations.

    Science.gov (United States)

    Ell, Shawn W; Smith, David B; Peralta, Gabriela; Hélie, Sébastien

    2017-08-01

    When interacting with categories, representations focused on within-category relationships are often learned, but the conditions promoting within-category representations and their generalizability are unclear. We report the results of three experiments investigating the impact of category structure and training methodology on the learning and generalization of within-category representations (i.e., correlational structure). Participants were trained on either rule-based or information-integration structures using classification (Is the stimulus a member of Category A or Category B?), concept (e.g., Is the stimulus a member of Category A, Yes or No?), or inference (infer the missing component of the stimulus from a given category) and then tested on either an inference task (Experiments 1 and 2) or a classification task (Experiment 3). For the information-integration structure, within-category representations were consistently learned, could be generalized to novel stimuli, and could be generalized to support inference at test. For the rule-based structure, extended inference training resulted in generalization to novel stimuli (Experiment 2) and inference training resulted in generalization to classification (Experiment 3). These data help to clarify the conditions under which within-category representations can be learned. Moreover, these results make an important contribution in highlighting the impact of category structure and training methodology on the generalization of categorical knowledge.

  16. European network infrastructures of observatories for terrestrial Global Change research

    Science.gov (United States)

    Vereecken, H.; Bogena, H.; Lehning, M.

    2009-04-01

    The earth's climate is significantly changing (e.g. IPCC, 2007) and thus directly affecting the terrestrial systems. The number and intensity hydrological extremes, such as floods and droughts, are continually increasing, resulting in major economical and social impacts. Furthermore, the land cover in Europe has been modified fundamentally by conversions for agriculture, forest and for other purposes such as industrialisation and urbanisation. Additionally, water resources are more than ever used for human development, especially as a key resource for agricultural and industrial activities. As a special case, the mountains of the world are of significant importance in terms of water resources supply, biodiversity, economy, agriculture, traffic and recreation but particularly vulnerable to environmental change. The Alps are unique because of the pronounced small scale variability they contain, the high population density they support and their central position in Europe. The Alps build a single coherent physical and natural environment, artificially cut by national borders. The scientific community and governmental bodies have responded to these environmental changes by performing dedicated experiments and by establishing environmental research networks to monitor, analyse and predict the impact of Global Change on different terrestrial systems of the Earths' environment. Several European network infrastructures for terrestrial Global Change research are presently immerging or upgrading, such as ICOS, ANAEE, LifeWatch or LTER-Europe. However, the strongest existing networks are still operating on a regional or national level and the historical growth of such networks resulted in a very heterogeneous landscape of observation networks. We propose therefore the establishment of two complementary networks: The NetwOrk of Hydrological observAtories, NOHA. NOHA aims to promote the sustainable management of water resources in Europe, to support the prediction of

  17. Dietary characterization of terrestrial mammals.

    Science.gov (United States)

    Pineda-Munoz, Silvia; Alroy, John

    2014-08-22

    Understanding the feeding behaviour of the species that make up any ecosystem is essential for designing further research. Mammals have been studied intensively, but the criteria used for classifying their diets are far from being standardized. We built a database summarizing the dietary preferences of terrestrial mammals using published data regarding their stomach contents. We performed multivariate analyses in order to set up a standardized classification scheme. Ideally, food consumption percentages should be used instead of qualitative classifications. However, when highly detailed information is not available we propose classifying animals based on their main feeding resources. They should be classified as generalists when none of the feeding resources constitute over 50% of the diet. The term 'omnivore' should be avoided because it does not communicate all the complexity inherent to food choice. Moreover, the so-called omnivore diets actually involve several distinctive adaptations. Our dataset shows that terrestrial mammals are generally highly specialized and that some degree of food mixing may even be required for most species.

  18. A new feruloyl amide derivative from the fruits of Tribulus terrestris.

    Science.gov (United States)

    Zhang, Xiaopo; Wei, Na; Huang, Jian; Tan, Yinfeng; Jin, Dejun

    2012-01-01

    A new feruloyl amide derivative, named tribulusamide C, was isolated from the fruits of Tribulus terrestris. Its structure was determined on the basis of spectroscopic analysis including IR, 1-D-, 2-D-NMR and HR-ESI-MS. The structure of tribulusamide C was characterised by a unit of pyrrolidine-2,5-dione, which distinguished it from other lignanamides previously isolated from the fruits of T. terrestris.

  19. Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

    Science.gov (United States)

    Ryan, S.; Ordonez, E.; Christiansen, E. L.; Lear, D. M.

    2010-01-01

    Open cell metallic foam core sandwich panel structures are of interest for application in spacecraft micrometeoroid and orbital debris shields due to their novel form and advantageous structural and thermal performance. Repeated shocking as a result of secondary impacts upon individual foam ligaments during the penetration process acts to raise the thermal state of impacting projectiles ; resulting in fragmentation, melting, and vaporization at lower velocities than with traditional shielding configurations (e.g. Whipple shield). In order to characterize the protective capability of these structures, an extensive experimental campaign was performed by the Johnson Space Center Hypervelocity Impact Technology Facility, the results of which are reported in this paper. Although not capable of competing against the protection levels achievable with leading heavy shields in use on modern high-risk vehicles (i.e. International Space Station modules), metallic foam core sandwich panels are shown to provide a substantial improvement over comparable structural panels and traditional low weight shielding alternatives such as honeycomb sandwich panels and metallic Whipple shields. A ballistic limit equation, generalized in terms of panel geometry, is derived and presented in a form suitable for application in risk assessment codes.

  20. Estimations of impact strength on reinforced concrete structures by the discrete element method

    International Nuclear Information System (INIS)

    Morikawa, H.; Kusano, N.; Koshika, N.; Aoyagi, T.; Hagiwara, Y.; Sawamoto, Y.

    1993-01-01

    There has been a rising interest in the response of reinforced concrete structures to impact loading, from the point of view in particular of disaster prevention at nuclear power facilities, and there is an urgent requirement for establishment of design methods against such type of loads. Structural damage on reinforced concrete structures under impact load includes local damage and global damage. The behavior of local damage, such as penetration into the structures, rear face scabbing, perforation, or spalling, has been difficult to estimate by numerical analysis, but over recent years research has advantaged and various analytical methods have been tried. The authors proposed a new approach for assessing local damage characteristics by applying the discrete element method (DEM), and verified that the behavior of a concrete slab suffering local damage may be qualitatively expressed. This was followed by the discussion of the quantitative evaluation of various constants used in the DEM analysis in reference. The authors apply the DEM to the simulation analysis of impact tests on reinforced concrete panels and analytical investigations are made on the local damage characteristics and response values that are difficult to assess through tests, in an attempt to evaluate the mechanism of local damage according to the hardness of the missiles

  1. Local damage to reinforced concrete structures caused by impact of aircraft engine missiles. Pt. 2

    International Nuclear Information System (INIS)

    Sugano, T.; Tsubota, H.; Kasai, Y.; Koshika, N.; Itoh, C.; Shirai, K.; Von Riesemann, W.A.; Bickel, D.C.; Parks, M.B.

    1993-01-01

    Three sets of impact tests, small-, intermediate-, and full-scale tests, have been executed to determine local damage to reinforced concrete structures caused by the impact of aircraft engine missiles. The results of the test program showed that (1) the use of the similarity law is appropriate, (2) suitable empirical formulas exist for predicting the local damage caused by rigid missiles, (3) reduction factors may be used for evaluating the reduction in local damage due to the deformability of the engines, (4) the reinforcement ratio has no effect on local damage, and (5) the test results could be adequately predicted using nonlinear response analysis. (orig.)

  2. A study for structural safety of ISER reactor building under impact load

    International Nuclear Information System (INIS)

    Takeuchi, Yoichiro; Hasegawa, Toshiyasu; Mutoh, Atsushi; Wakabayashi, Hiroaki.

    1991-01-01

    ISER (Inherently Safe and Economical Reactor) proposed in Japan by an academic circle and industries is expected to be used world-wide particularly in developing countries where an energy crunch is feared in the 21-st century. A certain level of hardened structures for plant safety seems to be effective and may be required by the regulatory body, since the ISER is claimed to be inherently safe even against a kind of external load. This paper concerns impact resistant design of ISER. A brief state-of-the-art review on related works, impact resistant design flow and results of some preliminary analysis of a proposed ISER model is also presented. (author)

  3. Evaluation of underground pipe-structure interface for surface impact load

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shen, E-mail: swang@terrapower.com

    2017-06-15

    Highlights: • A simple method is proposed for the evaluation of underground pipelines for surface impact load considering the effect of a nearby pipe-structure interface. • The proposed simple method can be used to evaluate the magnitude of damage within a short period of time after accidental drop occurs. • The proposed method is applied in a practical example and compared by using finite element analysis. - Abstract: Nuclear safety related buried pipelines need to be assessed for the effects of postulated surface impact loads. In published solutions, the buried pipe is often considered within an elastic half space without interference with other underground structures. In the case that a surface impact occurs in short distance from an underground pipe-structure interface, this boundary condition will further complicate the buried pipe evaluation. Neglecting such boundary effect in the assessment may lead to underestimating potential damage of buried pipeline, and jeopardizing safety of the nuclear power plant. Comprehensive analysis of such structure-pipe-soil system is often subjected to availability of state-of-art finite element tools, as well as costly and time consuming. Simple, but practical conservative techniques have not been established. In this study, a mechanics based solution is proposed in order to assess the magnitude of damage to a buried pipeline beneath a heavy surface impact considering the effect of a nearby pipe-structure interface. The proposed approach provides an easy to use tool in the early stage of evaluation before the decision of applying more costly technique can be made by owner of the nuclear facility.

  4. Evaluation of underground pipe-structure interface for surface impact load

    International Nuclear Information System (INIS)

    Wang, Shen

    2017-01-01

    Highlights: • A simple method is proposed for the evaluation of underground pipelines for surface impact load considering the effect of a nearby pipe-structure interface. • The proposed simple method can be used to evaluate the magnitude of damage within a short period of time after accidental drop occurs. • The proposed method is applied in a practical example and compared by using finite element analysis. - Abstract: Nuclear safety related buried pipelines need to be assessed for the effects of postulated surface impact loads. In published solutions, the buried pipe is often considered within an elastic half space without interference with other underground structures. In the case that a surface impact occurs in short distance from an underground pipe-structure interface, this boundary condition will further complicate the buried pipe evaluation. Neglecting such boundary effect in the assessment may lead to underestimating potential damage of buried pipeline, and jeopardizing safety of the nuclear power plant. Comprehensive analysis of such structure-pipe-soil system is often subjected to availability of state-of-art finite element tools, as well as costly and time consuming. Simple, but practical conservative techniques have not been established. In this study, a mechanics based solution is proposed in order to assess the magnitude of damage to a buried pipeline beneath a heavy surface impact considering the effect of a nearby pipe-structure interface. The proposed approach provides an easy to use tool in the early stage of evaluation before the decision of applying more costly technique can be made by owner of the nuclear facility.

  5. Asynchronous exposure to global warming: freshwater resources and terrestrial ecosystems

    International Nuclear Information System (INIS)

    Gerten, Dieter; Lucht, Wolfgang; Ostberg, Sebastian; Heinke, Jens; Kundzewicz, Zbigniew W; Rastgooy, Johann; Schellnhuber, Hans Joachim; Kowarsch, Martin; Kreft, Holger; Warren, Rachel

    2013-01-01

    This modelling study demonstrates at what level of global mean temperature rise (ΔT g ) regions will be exposed to significant decreases of freshwater availability and changes to terrestrial ecosystems. Projections are based on a new, consistent set of 152 climate scenarios (eight ΔT g trajectories reaching 1.5–5 ° C above pre-industrial levels by 2100, each scaled with spatial patterns from 19 general circulation models). The results suggest that already at a ΔT g of 2 ° C and mainly in the subtropics, higher water scarcity would occur in >50% out of the 19 climate scenarios. Substantial biogeochemical and vegetation structural changes would also occur at 2 ° C, but mainly in subpolar and semiarid ecosystems. Other regions would be affected at higher ΔT g levels, with lower intensity or with lower confidence. In total, mean global warming levels of 2 ° C, 3.5 ° C and 5 ° C are simulated to expose an additional 8%, 11% and 13% of the world population to new or aggravated water scarcity, respectively, with >50% confidence (while ∼1.3 billion people already live in water-scarce regions). Concurrently, substantial habitat transformations would occur in biogeographic regions that contain 1% (in zones affected at 2 ° C), 10% (3.5 ° C) and 74% (5 ° C) of present endemism-weighted vascular plant species, respectively. The results suggest nonlinear growth of impacts along with ΔT g and highlight regional disparities in impact magnitudes and critical ΔT g levels. (letter)

  6. Workshop on Oxygen in the Terrestrial Planets

    Science.gov (United States)

    2004-01-01

    This volume contains abstracts that have been accepted for presentation at the Workshop on Oxygen in the Terrestrial Planets, July 20-23,2004, Santa Fe, New Mexico. The contents include: 1) Experimental Constraints on Oxygen and Other Light Element Partitioning During Planetary Core Formation; 2) In Situ Determination of Fe(3+)/SigmaFe of Spinels by Electron Microprobe: An Evaluation of the Flank Method; 3) The Effect of Oxygen Fugacity on Large-Strain Deformation and Recrystallization of Olivine; 4) Plagioclase-Liquid Trace Element Oxygen Barometry and Oxygen Behaviour in Closed and Open System Magmatic Processes; 5) Core Formation in the Earth: Constraints from Ni and Co; 6) Oxygen Isotopic Compositions of the Terrestrial Planets; 7) The Effect of Oxygen Fugacity on Electrical Conduction of Olivine and Implications for Earth s Mantle; 8) Redox Chemical Diffusion in Silicate Melts: The Impact of the Semiconductor Condition; 9) Ultra-High Temperature Effects in Earth s Magma Ocean: Pt and W Partitioning; 10) Terrestrial Oxygen and Hydrogen Isotope Variations: Primordial Values, Systematics, Subsolidus Effects, Planetary Comparisons, and the Role of Water; 11) Redox State of the Moon s Interior; 12) How did the Terrestrial Planets Acquire Their Water?; 13) Molecular Oxygen Mixing Ratio and Its Seasonal Variability in the Martian Atmosphere; 14) Exchange Between the Atmosphere and the Regolith of Mars: Discussion of Oxygen and Sulfur Isotope Evidence; 15) Oxygen and Hydrogen Isotope Systematics of Atmospheric Water Vapor and Meteoric Waters: Evidence from North Texas; 16) Implications of Isotopic and Redox Heterogeneities in Silicate Reservoirs on Mars; 17) Oxygen Isotopic Variation of the Terrestrial Planets; 18) Redox Exchanges in Hydrous Magma; 19) Hydrothermal Systems on Terrestrial Planets: Lessons from Earth; 20) Oxygen in Martian Meteorites: A Review of Results from Mineral Equilibria Oxybarometers; 21) Non-Linear Fractionation of Oxygen Isotopes Implanted in

  7. Structural-Phase Transformations of CuZn Alloy Under Thermal-Impact Cycling

    Science.gov (United States)

    Potekaev, A. I.; Chaplygina, A. A.; Kulagina, V. V.; Chaplygin, P. A.; Starostenkov, M. D.; Grinkevich, L. S.

    2017-02-01

    Using the Monte Carlo method, special features of structural - phase transformations in β-brass are investigated during thermal impact using thermal cycling as an example (a number of successive order - disorder and disorder - order phase transitions in the course of several heating - cooling cycles). It is shown that a unique hysteresis is observed after every heating and cooling cycle, whose presence indicates irreversibility of the processes, which suggests a difference in the structural - phase states both in the heating and cooling stages. A conclusion is drawn that the structural - phase transformations in the heating and cooling stages occur within different temperature intervals, where the thermodynamic stimuli of one or the other structural - phase state are low. This is also demonstrated both in the plots of configurational energy, long- and short-range order parameter, atomic structure variations, and structural - phase state distributions. Simultaneously, there coexist ordered and disordered phases and a certain collection of superstructure domains. This implies the presence of low - stability states in the vicinity of the order - disorder phase transition. The results of investigations demonstrate that the structural - phase transitions within two successive heating and cooling cycles at the same temperature are different in both stages. These changes, though not revolutionary, occur in every cycle and decrease with the increasing cycle number. In fact, the system undergoes training with a tendency towards a certain sequence of structural - phase states.

  8. Development of an ultrasonic nondestructive inspection method for impact damage detection in composite aircraft structures

    Science.gov (United States)

    Capriotti, M.; Kim, H. E.; Lanza di Scalea, F.; Kim, H.

    2017-04-01

    High Energy Wide Area Blunt Impact (HEWABI) due to ground service equipment can often occur in aircraft structures causing major damages. These Wide Area Impact Damages (WAID) can affect the internal components of the structure, hence are usually not visible nor detectable by typical one-sided NDE techniques and can easily compromise the structural safety of the aircraft. In this study, the development of an NDI method is presented together with its application to impacted aircraft frames. The HEWABI from a typical ground service scenario has been previously tested and the desired type of damages have been generated, so that the aircraft panels could become representative study cases. The need of the aircraft industry for a rapid, ramp-friendly system to detect such WAID is here approached with guided ultrasonic waves (GUW) and a scanning tool that accesses the whole structure from the exterior side only. The wide coverage of the specimen provided by GUW has been coupled to a differential detection approach and is aided by an outlier statistical analysis to be able to inspect and detect faults in the challenging composite material and complex structure. The results will be presented and discussed with respect to the detection capability of the system and its response to the different damage types. Receiving Operating Characteristics curves (ROC) are also produced to quantify and assess the performance of the proposed method. Ongoing work is currently aimed at the penetration of the inner components of the structure, such as shear ties and C-frames, exploiting different frequency ranges and signal processing techniques. From the hardware and tool development side, different transducers and coupling methods, such as air-coupled transducers, are under investigation together with the design of a more suitable scanning technique.

  9. Vibration Control of Structures using Vibro-Impact Nonlinear Energy Sinks

    Directory of Open Access Journals (Sweden)

    M. Ahmadi

    2016-09-01

    Full Text Available Using Vibro-Impact Nonlinear Energy Sinks (VI NESs is one of the novel strategies to control structural vibrations and mitigate their seismic response. In this system, a mass is tuned on the structure floor, so that it has a specific distance from an inelastic constraint connected to the floor mass. In case of structure stimulation, the displaced VI NES mass collides with the  inelastic constraint and upon impacts, energy is dissipated. In the present work, VI NES is studied when its parameters, including clearance and stiffness ratio, are simultaneously optimized. Harmony search as a recent meta-heuristic algorithm is efficiently specialized and utilized for the aforementioned continuous optimization problem. The optimized attached VI NES is thus shown to be capable of interacting with the primary structure over a wide range of frequencies. The resulting controlled response is then investigated, in a variety of low and medium rise steel moment frames, via nonlinear dynamic time history analyses. Capability of the VI NES to dissipate siesmic input energy of earthquakes and their capabilitiy in reducing response of srtructures effectively, through vibro-impacts between the energy sink’s mass and the floor mass, is discussed by extracting several performance indices and the corresponding Fourier spectra. Results of the numerical simulations done on some structural model examples reveal that the optimized VI NES has caused successive redistribution of energy from low-frequency high-amplitude vibration modes to high-frequency low-amplitude modes, bringing about the desired attenuation of the structural responses.

  10. Mercury Exposure Affects the Reproductive Success of a Free-living Terrestrial Songbird, the Carolina Wren, (Thryothrus ludovicianus)

    Science.gov (United States)

    The impacts of mercury contamination on aquatic-feeding wildlife are well-established, but recent attention has focused on the effects of mercury on species in terrestrial ecosystems. Despite mounting evidence of mercury accumulation in terrestrial ecosystems, there is little dat...

  11. Aerosol-induced thermal effects increase modelled terrestrial photosynthesis and transpiration

    International Nuclear Information System (INIS)

    Steiner, Allison L.; Chameides, W.L.

    2005-01-01

    Previous studies suggest that the radiative effects of atmospheric aerosols (reducing total radiation while increasing the diffuse fraction) can enhance terrestrial productivity. Here, simulations using a regional climate/terrestrial biosphere model suggest that atmospheric aerosols could also enhance terrestrial photosynthesis and transpiration through an interaction between solar radiation, leaf temperature and stomatal conductance. During midday, clear-sky conditions, sunlit-leaf temperatures can exceed the optimum for photosynthesis, depressing both photosynthesis and transpiration. Aerosols decrease surface solar radiation, thereby reducing leaf temperatures and enhancing sunlit-leaf photosynthesis and transpiration. This modelling study finds that, under certain conditions, this thermal response of aerosols can have a greater impact on photosynthesis and transpiration than the radiative response. This implies that a full understanding of the impact of aerosols on climate and the global carbon cycle requires consideration of the biophysical responses of terrestrial vegetation as well as atmospheric radiative and thermodynamic effects

  12. A terrestrial ecosystem model (SOLVEG) coupled with atmospheric gas and aerosol exchange processes

    International Nuclear Information System (INIS)

    Katata, Genki; Ota, Masakazu

    2017-01-01

    In order to predict the impact of atmospheric pollutants (gases and aerosols) to the terrestrial ecosystem, new schemes for calculating the processes of dry deposition of gases and aerosols, and water and carbon cycles in terrestrial ecosystems were implemented in the one-dimensional atmosphere-SOiL-VEGetation model, SOLVEG. We made performance tests at various vegetation areas to validate the newly developed schemes. In this report, the detail in each modeled process is described with an instruction how to use the modified SOLVEG. The framework of 'terrestrial ecosystem model' was developed for investigation of a change in water, energy, and carbon cycles associated with global warming and air pollution and its impact on terrestrial ecosystems. (author)

  13. Analytical, Experimental, and Modelling Studies of Lunar and Terrestrial Rocks

    Science.gov (United States)

    Haskin, Larry A.

    1997-01-01

    The goal of our research has been to understand the paths and the processes of pla