WorldWideScience

Sample records for altitudinal field loss

  1. Bilateral occipital lobe infarction with altitudinal field loss following radiofrequency cardiac catheter ablation

    OpenAIRE

    Chen Celia S; Lee Andrew W; Luu Susie T

    2010-01-01

    Abstract Background Bilateral stroke following radiofrequency catheter ablation is an unusual complication and may result in bilateral altitudinal visual field defects. Bilateral altitudinal visual field defects usually result from prechiasmal pathology causing damage to both retinas or optic nerves and rarely from bilateral symmetric damage to the post chiasmal visual pathways. Case presentation A 48-year-old man complained of visual disturbance on wakening following radiofrequency catheter ...

  2. Bilateral occipital lobe infarction with altitudinal field loss following radiofrequency cardiac catheter ablation

    Directory of Open Access Journals (Sweden)

    Chen Celia S

    2010-03-01

    Full Text Available Abstract Background Bilateral stroke following radiofrequency catheter ablation is an unusual complication and may result in bilateral altitudinal visual field defects. Bilateral altitudinal visual field defects usually result from prechiasmal pathology causing damage to both retinas or optic nerves and rarely from bilateral symmetric damage to the post chiasmal visual pathways. Case presentation A 48-year-old man complained of visual disturbance on wakening following radiofrequency catheter ablation. The patient had a CHADS score of 1 pre-operatively and no complications were noted intra-operatively. Examination revealed a bilateral superior altitudinal defect and MRI of the brain showed multifocal areas of infarction predominantly involving the occipital lobes which correlated to with the visual deficits. Conclusion While the risk of thromboembolism and perioperative stroke during radiofrequency catheter ablation is small, it is not insignificant.

  3. Nitrogen Losses from Flooded Rice Field

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A field microplot experiment was conducted during the tillering stage of paddy rice to investigate nitrogen (N) losses from flooded rice fields following fertilizer application. After application of ammonium bicarbonate,most of nitrogen in the floodwater was present as NHq-N and its concentration varied widely with time.Concentrations of both NO3-N and NO2-N in the floodwater were low due to the weakened nitrification.Under flooded anaerobic reducing conditions, soil solution concentrations of NO3-N and NH4-N were not high, ranging from 0.6 mg L- 1 to 4.8 mg L-1, and decreased with soil depth. However, the groundwater was still contaminated with NO3-N and NH4-N. Rainfall simulation tests showed that the N losses via runoff in rice fields were closely related to the time intervals between fertilizer applications and rainfall events. When a large rain fell for a short period after fertilizer application, the N losses via runoff could be large, which could have a considerable effect on surface water quality. Both irrigation and N fertilizer application must be controlled and managed with great care to minimize N losses via runoff from agricultural land.

  4. Reading performance and central field loss.

    Science.gov (United States)

    Kanonidou, E

    2011-04-01

    Age-related macular degeneration is a major cause of blindness in Europe and the U.S. and a leading cause of significant loss of visual acuity in elderly patients. Reading is a key visual task in everyday living involving a synthesis of a number of different motor, sensory and cognitive functions. When the centre of a reader's visual field is obscured, reading speed declines and oculomotor pattern differs, compared to normal reading. Improvement in the generation of visual stimuli using computer-generated images and projection/display systems as well as advances in eye movement recording techniques, including infrared pupil tracking and magnetic search coils, have contributed greatly to our understanding of these sensorimotor abnormalities. The developed reading strategies have been thoroughly investigated in individuals with central field loss either induced artificially or related to eye pathology.The following review aims at presenting the contemporary literature regarding the sensory and oculomotor deficits in reading ability, resulting from central field loss and should contribute to a greater understanding of the functional visual deficit caused by this visual impairment.

  5. Altitudinal Levels and Altitudinal Limits in High Mountains

    Institute of Scientific and Technical Information of China (English)

    Matthias Kuhle

    2007-01-01

    In lowlands climate-specific processes due to weathering and erosion are dominant, whilst the geomorphology of mountains is dependent on the geologic-tectonic structure, i.e., the energy of erosion that increases according to the vertical. The expression "extremely high mountains" has been established as the extreme of a continuous mountain classification. It has to be understood in terms of geomorphology, glaciology and vegetation.Correspondence of the planetary and hypsometric change of forms is of great value as synthetic explanation. It is confirmed with regard to vegetation,periglacial geomorphology and glaciology. Due to the world-wide reconstruction of the snowline its paleoclimatic importance increases, too. Apart from lower limits the periglacial and glacial altitudinal levels also show zones of optimum development and climatic upper limits in the highest mountains of the earth. According to the proportion of the altitudinal levels a classification as to arid, temperate and humid high mountains has been carried out.

  6. The Electron Losses and Fields Investigation

    Science.gov (United States)

    Bingley, L.; Angelopoulos, V.; Caron, R.; Zarifian, A.; Miller, J.; Gildemeister, A.; Schoen, B.; Tsai, E.; Berger, S.; Zhang, F.; Subramanian, A.; Chung, M.; Runov, A.; Cruce, P. R.

    2015-12-01

    The Electron Losses and Fields Investigation (ELFIN), is a joint NASA/NSF funded project at the University of California, Los Angeles focusing on eliminating the current deficit in the understanding of the innate physical processes behind geomagnetic storms. Set to launch in 2017, the mission takes advantage of a 3U+ CubeSat design to reduce cost and complexity traditionally associated with a space weather mission of this kind. This mission seeks to quantify the precipitation of relativistic electrons from the radiation belts using a pair of energetic particle detectors (EPDs). The spacecraft will also fly a fluxgate magnetometer (FGM) for determining the pitch angle distribution of the particles, which in conjunction with the EPDs will provide insight to the mechanisms responsible for their loss. Electromagnetic Ion Cyclotron (EMIC) waves are thought to be a significant contributor to the precipitation of electrons trapped in the magnetosphere; however without direct measurement to verify the exact energy range of the particles with high angular resolution, the precise role of these waves is as yet undetermined. ELFIN is unique as it is the first spacecraft that will perform direct pitch angle measurements of the high-energy electrons at the region in the ionosphere where the particles are being lost. Together with correlative measurements from THEMIS, Van Allen Probes and the upcoming ERG mission, ELFIN will provide a unique dataset of magnetospheric wave-particle interactions that will be able to contribute to a marked increase in the fidelity of current space weather models.

  7. Magnetic field influence on pulsed air arc anode mass loss

    International Nuclear Information System (INIS)

    Anode mass loss was studied in pulsed air arcs between two electrode pairs, 99.99% Ni/Ni and 99.5% Cu/Cu, in a transverse magnetic field. In both cases the anode mass loss decreased (by a factor of 2 for Cu and by a factor of 6 for Ni) when the magnetic field was increased up to 15-20 Oe and then remained approximately constant for Cu and decreased weakly for Ni. The observed dependences of anode mass loss were explained by the published behaviour of an arc motion in a magnetic field. The lattice parameter was decreased by the discharge treatment. The decrease was attributed to residual tensile stress produced on the arced surface. The lattice parameter of Ni increased with magnetic field, while for Cu it did not change substantially. The different behaviour is attributed to the magneto-plastic effect on magnetic Ni, which increases the plasticity with magnetic field. (paper)

  8. Altitudinal distribution limits of aquatic macroinvertebrates

    DEFF Research Database (Denmark)

    Madsen, Philip B.; Morabowen, Andrés; Andino, Patricio;

    2015-01-01

    altitudinal patterns in population densities, (ii) transplants of the five taxa upstream of their natural altitudinal limit to test the short-term (14days) effect on survival, and (iii) in situ experiments of locomotory activity as a proxy for animal response to relatively small differences in temperature (5...... relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits.......; larvae of Andesiops (Ephemeroptera), Claudioperla, (Plecoptera), Scirtes (Coleoptera) and Anomalocosmoecus (Trichoptera), and the amphipod Hyalella in an Ecuadorian glacier-fed stream (4100-4500ma.s.l.). The following were performed: (i) quantitative benthic sampling at three sites to determine...

  9. Reduction of Field Loss by a Video Processing System

    OpenAIRE

    Mirzoev, Dr. Timur

    2014-01-01

    Streaming of 60 de-interlaced fields per second digital uncompressed video with 720x480 resolution without a loss of video fields is one of the desired technologies by scientists in biomechanics. If it is possible to stream digital uncompressed video without dropped video fields, then a sophisticated computer analysis of the transmitted via IEEE 1394a connection video is possible. Such process is used in biomechanics when it is important to analyze athletes performance via streaming digital u...

  10. Anfibios de las Sierras Pampeanas Centrales de Argentina: diversidad y distribución altitudinal

    Directory of Open Access Journals (Sweden)

    Julián N. Lescano

    2015-09-01

    Full Text Available Amphibians from Sierras Pampeanas Centrales of Argentina: diversity and altitudinal distribution. Sierras Pampeanas Centrales (SPC mountains are located in Córdoba and San Luis provinces (Argentina and represent an area of unique biogeographic importance. In this paper we provide a synthesis about the knowledge of diversity and altitudinal distribution of anurans that inhabit SPC mountains. We compiled a species list through different information sources (field data, biological collections and bibliography. Using this information we characterize altitudinal distribution range of each species and analyze associations between species richness and composition and altitude gradient. We recorded 24 amphibians species belonging to five families. These species are heterogeneously distributed over the altitude gradient of SPC. We detect a linear negative relationship between altitude and species richness and defined assemblages associated with different altitude sectors. The results obtained in the paper represent basic information that will be useful to evaluate anthropogenic impact on this particular and fragile mountain system.

  11. On losses caused in RF cavities by longitudinal electric fields

    International Nuclear Information System (INIS)

    Rf modes with large longitudinal electric fields (div E vector unequal to 0) at the cavity wall systematically show worse rf properties than modes with div E vector identical with 0; e.g. enlarged rf residual losses. While magnetic residual losses R sub(res) proportional f2 are due to uncharged inhomogeneities in the oxide coating the metal, the electric residual losses R sub(orthogonal) occur via charged states in the oxide: the recharging of those states by tunnel exchange causes excitation across the energy gap of the superconductor yielding residual losses at high rf field strengths. The interaction of E sub(orthogonal) with the charges generate (longitudinal) phonons showing up as contribution to R sub(orthogonal). The resulting R sub(orthogonal) increases with E sub(orthogonal) and is nearly independent of frequency f, indicating the importance of R sub(orthogonal) for low frequency sc cavities, especially at high field strengths. In addition R sub(orthogonal) can account for the observed large residual losses of strip line modes in narrow junctions and joints between superconductors. (orig.)

  12. Eccentric gaze direction in patients with central field loss

    NARCIS (Netherlands)

    Verezen, C.A.; Hoyng, C.B.; Meulendijks, C.F.M.; Keunen, J.E.E.; Klevering, B.J.

    2011-01-01

    PURPOSE.: This study describes the binocular eccentric gaze direction (EGD) of 434 patients with binocular central field loss and presents a comparison with other studies on eccentric gaze behavior. METHODS.: We reviewed the records of 434 patients with bilateral central scotomas. Eligible patients

  13. Plasma Heating and Losses in Toroidal Multipole Fields

    Energy Technology Data Exchange (ETDEWEB)

    Armentrout, C. J.; Barter, J. D.; Breun, R. A.; Cavallo, A. J.; Drake, J. R.; Etzweiler,; Greenwood, J. R.

    1974-09-01

    The heating and loss of plasmas have been studied in three pulsed, toroidal multipole devices: a large levitated octupole, a small supported octupole and a very .small supported quadrupole. Plasmas are produced by gun injection and heated by electron and ion cyclotron resonance heating and ohmic heating. Electron cyclotron heating rates have been measured over a wide range of parameters, and the results are in quantitative agreement with stochastic heating theory. Electron cyclotron resonance heating produces ions with energies larger than predicted by theory. With the addition of a toroidal field, ohmic heating gives densities as high as 10{sup 13}cm{sup -3} in the toroidal quadrupole and 10{sup 12}cm{sup -3} in the small octupole. Plasma losses for n=5 x 10{sup 9}cm{sup -3} plasmas are inferred from Langmuir probe and Fabry-Perot interferometer measurements, and measured with special striped collectors on the wall and rings. The loss to a levitated ring is measured using a modulated light beam telemeter. The confinement is better than Bohm but considerably worse than classical. Low frequency convective cells which are fixed in space are observed. These cells around the ring are diminished when a weak toroidal field is added, and loss collectors show a vastly reduced flux to the rings. Analysis of the spatial density profile shows features of B-independent diffusion. The confinement is sensitive to some kinds of dc field errors, but surprisingly insensitive to perturbations of the ac confining field.

  14. Loss and Dynamic Magnetic Field Measurements in LHC Dipoles

    CERN Document Server

    Akhmedov, A A; Balaazi, I; Bottura, L; Gateau, M; Pugnat, P; Walckiers, L

    2002-01-01

    Knowledge of AC loss and dynamic magnetic field distortion in the main LHC dipoles is both important for the assessment of the accelerator performance and providing insight into the properties of assembled magnets. We measured the loss due to the current cycling in a few 1-meter long model dipoles, 15-meter long dipole prototypes and pre-series magnets. As expected the loss depends linearly on the rate of the current change. From the slope of this dependence, the contact resistance between the strands of the opposite layers of the cable, Rc, was evaluated for the inner winding of the dipole. We discuss the method to estimate the Rc value in the outer winding. The Rc value has been also derived independently from measurements of the magnetic field. For this, the ramp rate dependent component of the main field as well as of the harmonics has been measured. The main magnetic field measurements were performed using both stationary coils and Hall probes. Rotating coils were used to perform the harmonic measurement...

  15. Measuring Fast Ion Losses in a Reversed Field Pinch Plasma

    Science.gov (United States)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.

    2015-11-01

    The reversed field pinch (RFP) provides a unique environment to study fast ion confinement and transport. The RFP's weak toroidal field, strong magnetic shear, and ability to enter a 3D state provide a wide range of dynamics to study fast ions. Core-localized, 25 keV fast ions are sourced into MST by a tangentially injected hydrogen/deuterium neutral beam. Neutral particle analysis and measured fusion neutron flux indicate enhanced fast ion transport in the plasma core. Past experiments point to a dynamic loss of fast ions associated with the RFP's transition to a 3D state and with beam-driven, bursting magnetic modes. Consequently, fast ion transport and losses in the RFP have garnered recent attention. Valuable information on fast-ion loss, such as energy and pitch distributions, are sought to provide a better understanding of the transport mechanisms at hand. We have constructed and implemented two fast ion loss detectors (FILDs) for use on MST. The FILDs have two, independent, design concepts: collecting particles as a function of v⊥ or with pitch greater than 0.8. In this work, we present our preliminary findings and results from our FILDs on MST. This research is supported by US DOE.

  16. Tomography of Particle Plasmon Fields from Electron Energy Loss Spectroscopy

    Science.gov (United States)

    Hörl, Anton; Trügler, Andreas; Hohenester, Ulrich

    2013-08-01

    We theoretically investigate electron energy loss spectroscopy (EELS) of metallic nanoparticles in the optical frequency domain. Using a quasistatic approximation scheme together with a plasmon eigenmode expansion, we show that EELS can be rephrased in terms of a tomography problem. For selected single and coupled nanoparticles we extract the three-dimensional plasmon fields from a collection of rotated EELS maps. Our results pave the way for a fully three-dimensional plasmon-field tomography and establish EELS as a quantitative measurement device for plasmonics.

  17. Rotor Field Oriented Control with adaptive Iron Loss Compensation

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    1999-01-01

    It is well known from the literature that iron loses in an induction motor implies field angle estimation errors and hence detuning problems. In this paper a new method for estimating the iron loss resistor in an induction motor is presented. The method is based on a traditional dynamic model of ...... current controlled in a Field Oriented Control scheme. This deviation is used to force a MIT-rule based adaptive estimator. An adaptive compensator containing the developed estimator is introduced and verified by simulations and tested by real time experiments....

  18. Rotor Field Oriented Control with adaptive Iron Loss Compensation

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    1999-01-01

    It is well known from the literature that iron loses in an induction motor implies field angle estimation errors and hence detuning problems. In this paper a new method for estimating the iron loss resistor in an induction motor is presented. The method is based on a traditional dynamic model of ...... controlled in a Field Oriented Control scheme. This deviation is used to force a MIT-rule based adaptive estimator. An adaptive compensator containing the developed estimator is introduced and verified by simulations and tested by real time experiments....

  19. Partial Altitudinal Migration of a Himalayan Forest Pheasant

    OpenAIRE

    Norbu, Nawang; Wikelski, Martin C.; Wilcove, David S.; Partecke, Jesko; Ugyen; Tenzin, Ugyen; Sherub,; Tempa, Tshering

    2013-01-01

    Background Altitudinal migration systems are poorly understood. Recent advances in animal telemetry which enables tracking of migrants across their annual cycles will help illustrate unknown migration patterns and test existing hypotheses. Using telemetry, we show the existence of a complex partial altitudinal migration system in the Himalayas and discuss our findings to help better understand partial and altitudinal migration. Methodology/Principal Findings We used GPS/accelerometer tags to ...

  20. Quantifying Nitrogen Loss From Flooded Hawaiian Taro Fields

    Science.gov (United States)

    Deenik, J. L.; Penton, C. R.; Bruland, G. L.; Popp, B. N.; Engstrom, P.; Mueller, J. A.; Tiedje, J.

    2010-12-01

    In 2004 a field fertilization experiment showed that approximately 80% of the fertilizer nitrogen (N) added to flooded Hawaiian taro (Colocasia esculenta) fields could not be accounted for using classic N balance calculations. To quantify N loss through denitrification and anaerobic ammonium oxidation (anammox) pathways in these taro systems we utilized a slurry-based isotope pairing technique (IPT). Measured nitrification rates and porewater N profiles were also used to model ammonium and nitrate fluxes through the top 10 cm of soil. Quantitative PCR of nitrogen cycling functional genes was used to correlate porewater N dynamics with potential microbial activity. Rates of denitrification calculated using porewater profiles were compared to those obtained using the slurry method. Potential denitrification rates of surficial sediments obtained with the slurry method were found to drastically overestimate the calculated in-situ rates. The largest discrepancies were present in fields greater than one month after initial fertilization, reflecting a microbial community poised to denitrify the initial N pulse. Potential surficial nitrification rates varied between 1.3% of the slurry-measured denitrification potential in a heavily-fertilized site to 100% in an unfertilized site. Compared to the use of urea, fish bone meal fertilizer use resulted in decreased N loss through denitrification in the surface sediment, according to both porewater modeling and IPT measurements. In addition, sub-surface porewater profiles point to root-mediated coupled nitrification/denitrification as a potential N loss pathway that is not captured in surface-based incubations. Profile-based surface plus subsurface coupled nitrification/denitrification estimates were between 1.1 and 12.7 times denitrification estimates from the surface only. These results suggest that the use of a ‘classic’ isotope pairing technique that employs 15NO3- in fertilized agricultural systems can lead to a drastic

  1. Patterns of non-embolic transient monocular visual field loss.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Plant, G T

    2013-07-01

    The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical history or family history of migraine, eye affected, onset, duration and offset, perception (pattern, positive and negative symptoms), associated headache and autonomic symptoms, attack frequency, and treatment response to nifedipine. We identified 77 patients (28 male and 49 female). Mean age of onset was 37 years (range 14-77 years). The neTMVL was limited to the right eye in 36 % to the left in 47 % and occurred independently in either eye in 5 % of cases. A past medical history of migraine was present in 12 % and a family history in 8 %. Headache followed neTMVL in 14 % and was associated with autonomic features in 3 %. The neTMB was perceived as grey in 35 %, white in 21 %, black in 16 % and as phosphenes in 9 %. Most frequently neTMVL was patchy 20 %. Recovery of vision frequently resembled attack onset in reverse. In 3 patients without associated headache the loss of vision was permanent. Treatment with nifedipine was initiated in 13 patients with an attack frequency of more than one per week and reduced the attack frequency in all. In conclusion, this large series of patients with neTMVL permits classification into five types of reversible visual field loss (grey, white, black, phosphenes, patchy). Treatment response to nifidipine suggests some attacks to be caused by vasospasm.

  2. Weeds Cause Losses in Field Crops through Allelopathy

    Directory of Open Access Journals (Sweden)

    Tasawer ABBAS

    2016-03-01

    Full Text Available A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant residues, volatilization and root exudates. Weeds leave huge quantities of their residues in field and affect the associated, as well as succeeding crops, in various cropping systems. Liberation of allelochemicals from weeds affects the germination, stand establishment, growth, yield and physiology of crop plants. They cause substantial reduction in germination and growth of the crop plants by altering various physiological processes such as enzyme activity, protein synthesis, photosynthesis, respiration, cell division and enlargement, which ultimately leads to a significant reduction in crop yield. In crux, allelopathic weeds represent a potential threat for crop plants and cause economic losses.

  3. Comparison of field-scale herbicide runoff and volatilization losses: an eight-year field investigation.

    Science.gov (United States)

    Gish, Timothy J; Prueger, John H; Daughtry, Craig S T; Kustas, William P; McKee, Lynn G; Russ, Andrew L; Hatfield, Jerry L

    2011-01-01

    An 8-yr study was conducted to better understand factors influencing year-to-year variability in field-scale herbicide volatilization and surface runoff losses. The 21-ha research site is located at the USDA-ARS Beltsville Agricultural Research Center in Beltsville, MD. Site location, herbicide formulations, and agricultural management practices remained unchanged throughout the duration of the study. Metolachlor [2-chloro--(2-ethyl-6-methylphenyl)--(2-methoxy-1-methylethyl) acetamide] and atrazine [6-chloro--ethyl--(1-methylethyl)-1,3,5-triazine-2,4-diamine] were coapplied as a surface broadcast spray. Herbicide runoff was monitored from a month before application through harvest. A flux gradient technique was used to compute volatilization fluxes for the first 5 d after application using herbicide concentration profiles and turbulent fluxes of heat and water vapor as determined from eddy covariance measurements. Results demonstrated that volatilization losses for these two herbicides were significantly greater than runoff losses ( < 0.007), even though both have relatively low vapor pressures. The largest annual runoff loss for metolachlor never exceeded 2.5%, whereas atrazine runoff never exceeded 3% of that applied. On the other hand, herbicide cumulative volatilization losses after 5 d ranged from about 5 to 63% of that applied for metolachlor and about 2 to 12% of that applied for atrazine. Additionally, daytime herbicide volatilization losses were significantly greater than nighttime vapor losses ( < 0.05). This research confirmed that vapor losses for some commonly used herbicides frequently exceeds runoff losses and herbicide vapor losses on the same site and with the same management practices can vary significantly year to year depending on local environmental conditions.

  4. AC losses and transient field stability of PF-FSJS sample

    International Nuclear Information System (INIS)

    This series of 17 slides deals with AC losses and transient field stability of poloidal field full-size-joint sample) which is relevant to the poloidal field coils of ITER. The topic is divided into 6 parts: 1) general - AC losses, 2) conductor magnetization, 3) conductor calorimetry, 4) conclusion on AC losses, 5) stability, and 6) conclusion on stability

  5. AC losses and transient field stability of PF-FSJS sample

    Energy Technology Data Exchange (ETDEWEB)

    Zani, L

    2003-07-01

    This series of 17 slides deals with AC losses and transient field stability of poloidal field full-size-joint sample) which is relevant to the poloidal field coils of ITER. The topic is divided into 6 parts: 1) general - AC losses, 2) conductor magnetization, 3) conductor calorimetry, 4) conclusion on AC losses, 5) stability, and 6) conclusion on stability.

  6. Altitudinal divergence in maternal thermoregulatory behaviour may be driven by differences in selection on offspring survival in a viviparous lizard

    NARCIS (Netherlands)

    Uller, Tobias; While, Geoffrey M.; Cadby, Chloe D.; Harts, Anna; O'Connor, Katherine; Pen, Ido; Wapstra, Erik

    2011-01-01

    Plastic responses to temperature during embryonic development are common in ectotherms, but their evolutionary relevance is poorly understood. Using a combination of field and laboratory approaches, we demonstrate altitudinal divergence in the strength of effects of maternal thermal opportunity on o

  7. Dung Beetles along a Tropical Altitudinal Gradient: Environmental Filtering on Taxonomic and Functional Diversity

    Science.gov (United States)

    Nunes, Cássio Alencar; Braga, Rodrigo Fagundes; Figueira, José Eugênio Cortes; Neves, Frederico de Siqueira; Fernandes, G. Wilson

    2016-01-01

    Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will

  8. Influence of initial visual field sensitivity on visual field loss progression in open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Hentova-Senćanić Paraskeva

    2012-01-01

    Full Text Available Introduction. It is important to know the risk factors for visual field defect progression in order to predict the future development of glaucoma. Objective. To investigate the influence of visual field initial sensitivity on the rate of visual field progression. Methods. A minimum of five visual fields were performed using computerized perimetry (Octopus over a mean follow- up 4-year period (48.85±17.84 months in 64 persons (114 eyes with primary open angle glaucoma. The rate of change of the whole central visual field and each of the seven regions of the field were measured by linear regression analysis of the mean sensitivity value versus time. Based on the slope of the regression line of visual field mean sensitivity over time the eyes were divided into two groups: the group with stable and the group with progressive visual field. The comparison of the mean sensitivity of the whole central visual field between the groups was performed using the Mann-Whitney U-test. The Spearman rang correlation coefficient and the Spearman probability p values were calculated to assess the mean sensitivity of the whole central visual field and of each visual field regions determined at the beginning of the study. Results. The initial mean sensitivity of the whole central visual field was lower in the group with progressive visual field (16.62±6.35 dB. Correlation between the initial mean sensitivity and the slope of the regression line was negative. The lowest mean sensitivity was in the group with progressive visual field in the upper temporal (13.73±7.35 dB, nasal (14.74±7.23 dB and upper nasal (15.03±7.75 dB regions. Conclusion. The lower mean sensitivity value of the visual field, especially in the nasal and upper nasal visual field regions, carries a greater risk for delayed progressive loss of the visual field in persons with glaucoma.

  9. A Prospective Profile of Visual Field Loss following Stroke: Prevalence, Type, Rehabilitation, and Outcome

    OpenAIRE

    Rowe, Fiona J; David Wright; Darren Brand; Carole Jackson; Shirley Harrison; Tallat Maan; Claire Scott; Linda Vogwell; Sarah Peel; Nicola Akerman; Caroline Dodridge; Claire Howard; Tracey Shipman; Una Sperring; Sonia MacDiarmid

    2013-01-01

    Aims. To profile site of stroke/cerebrovascular accident, type and extent of field loss, treatment options, and outcome. Methods. Prospective multicentre cohort trial. Standardised referral and investigation protocol of visual parameters. Results. 915 patients were recruited with a mean age of 69 years (SD 14). 479 patients (52%) had visual field loss. 51 patients (10%) had no visual symptoms. Almost half of symptomatic patients (n = 226) complained only of visual field loss: almost half (n =...

  10. Ripple Field AC Losses in 10-MW Wind Turbine Generators With a MgB2 Superconducting Field Winding

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Magnusson, Niklas;

    2016-01-01

    and the ac armature winding is made with copper conductors. In such generators, the dc field winding is exposed to ac magnetic field ripples due to space harmonics from the armature. In generator design phases, the ac loss caused by these ripple fields needs to be evaluated to avoid local overheating...... and an excessive cooling budget. To determine the applicability of different design solutions in terms of ac losses, this paper estimates the ac loss level of 10-MW wind generator designs employing a MgB2 SC field winding. The effects on ac losses are compared between nonmagnetic and ferromagnetic teeth...... with different numbers of slots per pole per phase. The necessity of an electromagnetic shield is then discussed based on the obtained loss levels. The results show that the total ac loss is so small that ferromagnetic teeth can be applied in the generator design without using an electromagnetic shield....

  11. Digital Spectra and Analysis of Altitudinal Belts in Tianshan Mountains,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Baiping; MO Shenguo; WU Hongzhi; XIAO Fei

    2004-01-01

    Based on the framework of the geo-info spectra of montane altitudinal belts, this paper firstly reviews six classification systems for the spectra of mountain altitudinal belts in China and considers that detailed regional study of altitudinal belts is the key for reaching standardization and systemization of mountain altitudinal belts. Only can this furtheridentify and resolve problems with the study of altitudinal belts. The factors forming the spectra of altitudinal belts are analyzed in the Tianshan Mountains of China, and a digital altitudinal belt system is constructed for the northern flank, Southern flank, the heartland, and Ilivalley in the west. The characteristics of each belt are revealed with a summarization of the pattern of areal differentiation of altitudinal belts.

  12. Altitudinal patterns of the flora of seed plants of Dawei Mountain in Yunnan Province,south China

    Institute of Scientific and Technical Information of China (English)

    WANG Juan; MA Qinyan; DU Fan; YANG Yuming

    2007-01-01

    Altitudinal gradient incorporates multiple resource gradients,which vary continuously in different fashions.It is important to study the mountain floristic patterns along altitudinal gradients which reveal the regular pattern of the flora along the environmental gradients,the changing trend of biodiversity patterns along the altitudinal gradient,and relevance of biological fitness.To explore the compositional characteristics and ecological significance of floristic patterns along altitudinal gradient in China National Nature Reserve of Dawei Mountain in the southeast of Yunnan Province,field investigations have been made to the flora along the two routes of the southwest slope and the northeast slope of the said reserve,including a vertical vegetation transect.Meanwhile,further investigations have also been made to the flora of Dawei Mountain,which has been accounted for in the literature,as Flora Yunnan,The Seed Plant in Yunnan,and so on.The structural characteristics of the flora and the altitudinal distribution pattern of its floristic components were analyzed.By applying systematic cluster analysis,the altitudinal position of the dividing line of floristic changes along altitudinal gradient was detected,and the effects of the montane climate on the vertical variation of floristic composition were studied.Conclusions were put forward.This paper can be summarized as follows:(1) The obvious boundary that differentiates tropical floristic elements is located at the altitude of approximately 1,500 m;it is reasonable to stipulate the boundary line between tropical rain forests and the evergreen broad-leaved forests.(2) The vertical vegetation spectrum made by cluster analysis shows that humid rain forests are below 700 m a.s.1,montane rain forests are between 700 and 1,500 m,monsoon evergreen broad-leaved forests are between 1,300 and 1,800 m,and montane mossy evergreen broad-leaved forests are above 1,800 m a.s.1.Nonrepresentative montane mossy dwarf forests (above

  13. AC losses in a HTS coil carrying DC current in AC external magnetic field

    International Nuclear Information System (INIS)

    We electrically measured AC losses in a Bi2223/Ag-sheathed pancake coil excited by a DC current in AC external magnetic field. Losses in the coil contain two kinds of loss components that are the magnetization losses and dynamic resistance losses. In the measurement, current leads to supply a current to the coil were specially arranged to suppress electromagnetic coupling between the coil current and the AC external magnetic field. A double pick-up coils method was used to suppress a large inductive voltage component contained in voltage signal for measuring the magnetization losses. It was observed that the magnetization losses were dependent on the coil current and that a peak of a curve of the loss factor vs. amplitude of the AC external magnetic field shifted to lower amplitude of the AC magnetic field as the coil current increased. This result suggests the full penetration magnetic field of the coil tape decreases as the coil current increases. The dynamic resistance losses were measured by measuring a DC voltage appearing between the coil terminals. It was observed that the DC voltage appearing in the coil subject to the AC external magnetic field was much larger than that in the coil subject to DC magnetic field

  14. Weeds Cause Losses in Field Crops through Allelopathy

    OpenAIRE

    Tasawer ABBAS; Tahira TABASSUM

    2016-01-01

    A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant resid...

  15. Assessment of Delta Nitrogen Losses (Delta NL) at the Field Level

    Science.gov (United States)

    We defined a new concept of field-level delta nitrogen (N) losses (Delta NL) as a comparison between management scenarios. We defined delta nitrogen losses (Delta NL) as a function of improved N use efficiencies of field management scenarios that reduce the average N inputs and/or modify other manag...

  16. A Prospective Profile of Visual Field Loss following Stroke: Prevalence, Type, Rehabilitation, and Outcome

    Directory of Open Access Journals (Sweden)

    Fiona J. Rowe

    2013-01-01

    Full Text Available Aims. To profile site of stroke/cerebrovascular accident, type and extent of field loss, treatment options, and outcome. Methods. Prospective multicentre cohort trial. Standardised referral and investigation protocol of visual parameters. Results. 915 patients were recruited with a mean age of 69 years (SD 14. 479 patients (52% had visual field loss. 51 patients (10% had no visual symptoms. Almost half of symptomatic patients (n=226 complained only of visual field loss: almost half (n=226 also had reading difficulty, blurred vision, diplopia, and perceptual difficulties. 31% (n=151 had visual field loss as their only visual impairment: 69% (n=328 had low vision, eye movement deficits, or visual perceptual difficulties. Occipital and parietal lobe strokes most commonly caused visual field loss. Treatment options included visual search training, visual awareness, typoscopes, substitutive prisms, low vision aids, refraction, and occlusive patches. At followup 15 patients (7.5% had full recovery, 78 (39% had improvement, and 104 (52% had no recovery. Two patients (1% had further decline of visual field. Patients with visual field loss had lower quality of life scores than stroke patients without visual impairment. Conclusions. Stroke survivors with visual field loss require assessment to accurately define type and extent of loss, diagnose coexistent visual impairments, and offer targeted treatment.

  17. Loss analysis of permanent magnet hybrid brushless machines with and without HTS field windings

    OpenAIRE

    Chau, KT; Liu, C; Li, W

    2010-01-01

    This paper presents and implements the power loss analysis of a new kind of permanent magnet hybrid brushless (PMHB) machines with and without using high-temperature superconductor (HTS) field windings. The circuit-field-torque time-stepping finite element method together with experiential equations is developed to perform power loss analysis of the PMHB machine. Experimentation is carried out to verify the proposed loss analysis. © 2006 IEEE.

  18. Prism therapy and visual rehabilitation in homonymous visual field loss.

    LENUS (Irish Health Repository)

    O'Neill, Evelyn C

    2011-02-01

    Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment.

  19. Neutrino energy loss by electron capture in magnetic field at the crusts of neutron stars

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-Jing; LUO Zhi-Quan

    2008-01-01

    Based on the p-f shell model,the effect of strong magnetic field on neutrino energy loss rates by electron capture is investigated.The calculations show that the magnetic field has only a slight effect on the neutrino energy loss rates in the range of 108-1013 G on the surfaces of most neutron stars.But for some magnetars,the range of the magnetic field is 1013-1018 G,and the neutrino energy loss rates are greatly reduced,even by more than four orders of magnitude due to the strong magnetic field.

  20. Prism therapy and visual rehabilitation in homonymous visual field loss.

    LENUS (Irish Health Repository)

    O'Neill, Evelyn C

    2012-02-01

    PURPOSE: Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment. METHODS: Twelve patients with acquired, documented HVFD were eligible to be included. All patients underwent specific vision-targeted, health-related QOL questionnaire and monocular and binocular Goldmann perimetry before commencing prism therapy. Patients were fitted with monocular prisms on the side of the HVFD with the base-in the direction of the field defect creating a peripheral optical exotropia and field expansion. After the treatment period, QOL questionnaires and perimetry were repeated. RESULTS: Twelve patients were included in the treatment group, 10 of whom were included in data analysis. Overall, there was significant improvement within multiple vision-related, QOL functioning parameters, specifically within the domains of general health (p < 0.01), general vision (p < 0.05), distance vision (p < 0.01), peripheral vision (p < 0.05), role difficulties (p < 0.05), dependency (p < 0.05), and social functioning (p < 0.05). Visual field expansion was shown when measured monocularly and binocularly during the study period in comparison with pretreatment baselines. CONCLUSIONS: Patients with HVFD demonstrate decreased QOL. Monocular sector prisms can improve the QOL and expand the visual field in these patients.

  1. Trade-off among different anti-herbivore defence strategies along an altitudinal gradient.

    Science.gov (United States)

    Dostálek, Tomáš; Rokaya, Maan Bahadur; Maršík, Petr; Rezek, Jan; Skuhrovec, Jiří; Pavela, Roman; Münzbergová, Zuzana

    2016-01-01

    The type and intensity of plant-herbivore interactions are likely to be altered under climate change as a consequence of differential dispersal rates of plants and their herbivores. Here, we studied variation in herbivore damage on Salvia nubicola in the field and compared its growth and defence strategies against herbivores in controlled conditions using seeds from populations along a broad altitudinal gradient. Our work is one of the first studies to simultaneously measure complex intraspecific variation in plant growth, direct and indirect defences as well as plant tolerance (ability to regrow) as a consequence of herbivore attack simulated by clipping. In the field, we found that plants experienced higher herbivore pressure in lower altitudes. In the greenhouse, plants grown from seeds collected in lower-altitude populations grew better and produced a higher content of phenolic compounds (direct defence) and volatile organic compounds (indirect defence) in response to simulated herbivory. However, there were no differences in tolerance and effect of S. nubicola extracts on the model generalist herbivore Spodoptera littoralis (direct defence) along the altitudinal gradient. Although we found that S. nubicola developed a range of defence strategies, the strategies do not seem to be used simultaneously in all populations even though most of them are correlated with altitudinal gradient. Our finding is in agreement with the current knowledge that co-expression of multiple defences might be costly for a plant, since investment in defensive traits is assumed to reduce the resource availability for growth and reproduction. Our study thus shows the importance of simultaneous study of different defence strategies since understanding these trade-offs could be necessary for detecting the mechanisms by which plants are able to cope with future climate change. PMID:27169609

  2. Trade-off among different anti-herbivore defence strategies along an altitudinal gradient

    Science.gov (United States)

    Dostálek, Tomáš; Rokaya, Maan Bahadur; Maršík, Petr; Rezek, Jan; Skuhrovec, Jiří; Pavela, Roman; Münzbergová, Zuzana

    2016-01-01

    The type and intensity of plant–herbivore interactions are likely to be altered under climate change as a consequence of differential dispersal rates of plants and their herbivores. Here, we studied variation in herbivore damage on Salvia nubicola in the field and compared its growth and defence strategies against herbivores in controlled conditions using seeds from populations along a broad altitudinal gradient. Our work is one of the first studies to simultaneously measure complex intraspecific variation in plant growth, direct and indirect defences as well as plant tolerance (ability to regrow) as a consequence of herbivore attack simulated by clipping. In the field, we found that plants experienced higher herbivore pressure in lower altitudes. In the greenhouse, plants grown from seeds collected in lower-altitude populations grew better and produced a higher content of phenolic compounds (direct defence) and volatile organic compounds (indirect defence) in response to simulated herbivory. However, there were no differences in tolerance and effect of S. nubicola extracts on the model generalist herbivore Spodoptera littoralis (direct defence) along the altitudinal gradient. Although we found that S. nubicola developed a range of defence strategies, the strategies do not seem to be used simultaneously in all populations even though most of them are correlated with altitudinal gradient. Our finding is in agreement with the current knowledge that co-expression of multiple defences might be costly for a plant, since investment in defensive traits is assumed to reduce the resource availability for growth and reproduction. Our study thus shows the importance of simultaneous study of different defence strategies since understanding these trade-offs could be necessary for detecting the mechanisms by which plants are able to cope with future climate change. PMID:27169609

  3. Mass Losses of Magnetized Rheological Mediums Subjected to Magnetic Field

    Science.gov (United States)

    Baev, A. R.; Matoussevitch, N. P.

    Theoretical analysis and experimental research of the film flowing of magnetorheologic fluids when infinitive solid plate is retrieving from the former mediums were carried out. We have got dependencies of fluids mass losses m vs: velocity of moving plate V; magnitude of magnetic intensity, its gradient and angle ϕ between direction of intensity lines and normal vector to plane of plate. It is shown that theoretical and experimental m(ϕ) is anisotropy one and may change its magnitude more than 10 times. Real behavior and extreme characteristics of m(ϕ) depends on rhelogiacal parameters of MRS and its magnetization. Obtained experimental data of dependence m(V) are in qualitative and quantitative agreement with the modernized theory.

  4. Floristic diversity and distribution pattern of plant communities along altitudinal gradient in Sangla Valley, Northwest Himalaya.

    Science.gov (United States)

    Sharma, Pankaj; Rana, J C; Devi, Usha; Randhawa, S S; Kumar, Rajesh

    2014-01-01

    Himalayas are globally important biodiversity hotspots and are facing rapid loss in floristic diversity and changing pattern of vegetation due to various biotic and abiotic factors. This has necessitated the qualitative and quantitative assessment of vegetation here. The present study was conducted in Sangla Valley of northwest Himalaya aiming to assess the structure of vegetation and its trend in the valley along the altitudinal gradient. In the forest and alpine zones of the valley, 15 communities were recorded. Study revealed 320 species belonging to 199 genera and 75 families. Asteraceae, Rosaceae, Apiaceae, and Ranunculaceae were dominant. Among genera, Artemisia followed by Polygonum, Saussurea, Berberis, and Thalictrum were dominant. Tree and shrub's density ranged from 205 to 600 and from 105 to 1030 individual per hectare, respectively, whereas herbs ranged from 22.08 to 78.95 individual/m(2). Nearly 182 species were native to the Himalaya. Maximum altitudinal distribution of few selected climate sensitive species was found to be highest in northeast and north aspects. This study gives an insight into the floristic diversity and community structure of the fragile Sangla Valley which was hitherto not available. PMID:25383363

  5. Field measurements of water and nitrogen losses under irrigated maize

    Science.gov (United States)

    Kengni, L.; Vachaud, G.; Thony, J. L.; Laty, R.; Garino, B.; Casabianca, H.; Jame, P.; Viscogliosi, R.

    1994-10-01

    An intensive multidisciplinary experiment has been conducted over several years at La Côte Saint-André, near Grenoble, France. The major objective is to determine an optimal fertilizer application scheme for an irrigated agricultural system. Such a scheme would not degrade the quality of the environment, and yet would maintain a profitable level of crop production. This study is explicitly related to the cultivation of irrigated maize, a major crop in the area. The various terms of the water balance (consumption, drainage, soil storage) and of the nitrogen cycle (mineralization, plant uptake, leaching) were obtained from intensive monitoring in the upper layer of the 0.8 m of soil which corresponds to the root zone of the crop. This entailed the combined use of a neutron moisture meter, tensiometers and soil suction cups. To determine the specific effects of fertilization and crop growth, there were different treatments. These corresponded to a traditional fertilizer application of 260 kg N ha -1, no fertilization, and bare soil, carried out within an area of approximately 2 ha. Several sites were instrumented on each treatment, one of them being specifically for the application and the monitoring of 15N-tagged fertilizer. The results have shown that, in terms of the water balance, irrigation water management is extremely efficient, as drainage losses under the maize culture are negligible during the crop cycle. The situation is totally different, however, during the intercrop period (October-April), owing to rainfall. Then the soil is left bare and evaporation is very small, and now the drainage corresponds to about 90% of total inputs from precipitation. In terms of the nitrogen cycle, the results showed clearly that up to 150 kg N ha -1 was produced by mineralization in the soil. Nitrogen leaching beyond the root zone during the crop cycle is negligible, regardless of the rate of fertilizer application, as a result of the very small amount of drainage, despite

  6. Partial altitudinal migration of a Himalayan Forest pheasant.

    Directory of Open Access Journals (Sweden)

    Nawang Norbu

    Full Text Available BACKGROUND: Altitudinal migration systems are poorly understood. Recent advances in animal telemetry which enables tracking of migrants across their annual cycles will help illustrate unknown migration patterns and test existing hypotheses. Using telemetry, we show the existence of a complex partial altitudinal migration system in the Himalayas and discuss our findings to help better understand partial and altitudinal migration. METHODOLOGY/PRINCIPAL FINDINGS: We used GPS/accelerometer tags to monitor the migration of Satyr tragopan (Tragopan satyra in the Bhutan Himalayas. We tagged 38 birds from 2009 - 2011 and found that tragopans are partially migratory. Fall migration lasted from the 3(rd week of September till the 3(rd week of November with migrants traveling distances ranging from 1.25 km to 13.5 km over 1 to 32 days. Snowfall did not influence the onset of migration. Return migration started by the 1(st week of March and lasted until the 1(st week of April. Individuals returned within 4 to 10 days and displayed site fidelity. One bird switched from being a migrant to a non-migrant. Tragopans displayed three main migration patterns: 1 crossing multiple mountains; 2 descending/ascending longitudinally; 3 moving higher up in winter and lower down in summer. More females migrated than males; but, within males, body size was not a factor for predicting migrants. CONCLUSIONS/SIGNIFICANCE: Our observations of migrants traversing over multiple mountain ridges and even of others climbing to higher elevations is novel. We support the need for existing hypotheses to consider how best to explain inter- as well as intra-sexual differences. Most importantly, having shown that the patterns of an altitudinal migration system are complex and not a simple up and down slope movement, we hope our findings will influence the way altitudinal migrations are perceived and thereby contribute to a better understanding of how species may respond to climate change.

  7. Alternating magnetic field losses in ATLAS type aluminium stabilized NbTi superconductors

    CERN Document Server

    Boxman, E W; ten Kate, H H J

    2002-01-01

    During ramping up- and down of the current in large-scale magnets the ramp losses are an important factor affecting the thermal and electro-magnetic stability of the system. The calculation of the losses is not straightforward due to the large dimensions of the conductor (~600 mm/sup 2/) implying that diffusion effects have to be taken into account. The AC-losses of the Al stabilized NbTi cable conductors used in the ATLAS magnet system were measured in 0.5 m long samples, using an inductive method with pick-up coils as well as the calorimetric method. External varying magnetic fields up to 2 tesla amplitude were applied parallel and perpendicular to the conductor wide surface. The results are compared to theory. It is found that hysteresis loss, eddy current loss in the Aluminum cladding and cable-to-cladding coupling loss contribute most to the AC loss. (5 refs).

  8. Velocity-space particle loss in field-reversed theta pinches

    International Nuclear Information System (INIS)

    A field-reversed theta pinch (FRTP) is a compact device for magnetic fusion. It has attracted much attention in recent years since encouraging experimental results have been obtained. However, the definite causes for the observed particle loss rate and plasma rotation are not well known. In this work, we study the velocity-space particle loss (VSPL), i.e., particle loss due to the existence of a loss region in velocity space, in FRTP's in order to have a better understanding about the characteristics of this device

  9. Pressure losses and flow field distortion induced by tip clearance of centrifugal and axial compressors

    Science.gov (United States)

    Senoo, Yasutoshi

    1987-03-01

    The flow field near the tip of compressor rotor blades is distorted by leakage through the tip clearance and the performance of the compressor is deteriorated. The literature regarding the tip clearance of compressor blades consists of computational fluid mechanics and experimental studies on the flow field and the pressure loss. Empirical equations expressing the pressure loss and the efficiency drop are varied. They relate to the lift coefficient in different ways, depending upon the ways of understanding the mechanics of pressure losses. These methods are examined and compared. Also, a brief discussion is made on the optimum value of the tip clearance.

  10. A technique for simulating visual field losses in virtual environments to study human navigation.

    Science.gov (United States)

    Fortenbaugh, Francesca C; Hicks, John C; Hao, Lei; Turano, Kathleen A

    2007-08-01

    The following paper describes a new technique for simulating peripheral field losses in virtual environments to study the roles of the central and peripheral visual fields during navigation. Based on Geisler and Perry's (2002) gaze-contingent multiresolution display concept, the technique extends their methodology to work with three-dimensional images that are both transformed and rendered in real time by a computer graphics system. In order to assess the usefulness of this method for studying visual field losses, an experiment was run in which seven participants were required to walk to a target tree in a virtual forest as quickly and efficiently as possible while artificial head and eye-based delays were systematically introduced. Bilinear fits were applied to the mean trial times in order to assess at what delay lengths breaks in performance could be observed. Results suggest that breaks occur beyond the current delays inherent in the system. Increases in trial times across all delays tested were also observed when simulated peripheral field losses were applied compared to full FOV conditions. Possible applications and limitations of the system are discussed. The source code needed to program visual field losses can be found at lions.med.jhu.edu/archive/turanolab/Simulated_Visual_Field_Loss_Code.html. PMID:17958167

  11. ANALYSIS OF HIGH FIELD NON-LINEAR LOSSES ON SRF SURFACES DUE TO SPECIFIC TOPOGRAPHIC ROUGHNESS

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xu,Charles Reece,Michael Kelley

    2012-07-01

    The high-field performance of SRF cavities will eventually be limited by the realization of fundamental material limits, whether it is Hc1 or Hsh, or some derivative thereof, at which the superconductivity is lost. Before reaching this fundamental field limit at the macro level, it must be encountered at localized, perhaps microscopic, sites of field enhancement due to local topography. If such sites are small enough, they may produce thermally stabilized normal-conducting regions which contribute non-linear losses when viewed from the macro resonant field perspective, and thus produce degradation in Q0. We have undertaken a calculation of local surface magnetic field enhancement from specific fine topographic structure by conformal mapping method and numerically. A solution of the resulting normal conducting volume has been derived and the corresponding RF Ohmic loss simulated.

  12. How to Determine Losses in a Flow Field: A Paradigm Shifttowards the Second Law Analysis

    Directory of Open Access Journals (Sweden)

    Heinz Herwig

    2014-05-01

    Full Text Available Assuming that CFD solutions will be more and more used to characterizelosses in terms of drag for external flows and head loss for internal flows, we suggest toreplace single-valued data, like the drag force or a pressure drop, by field information aboutthe losses. These information are gained when the entropy generation in the flow field isanalyzed, an approach that often is called second law analysis (SLA, referring to the secondlaw of thermodynamics. We show that this SLA approach is straight-forward, systematicand helpful when it comes to the physical interpretation of the losses in a flow field. Variousexamples are given, including external and internal flows, two phase flow, compressible flowand unsteady flow. Finally, we show that an energy transfer within a certain process can beput into a broader perspective by introducing the entropic potential of an energy.

  13. A hand-held sensor for analyses of local distributions of magnetic fields and losses

    CERN Document Server

    Krismanic, G; Baumgartinger, N

    2000-01-01

    The paper describes a novel sensor for non-destructive analyses of local field and loss distributions in laminated soft magnetic cores, such as transformer cores. It was designed for rapid information on comparative local degrees of inhomogeneity, e.g., for the estimation of local building factors. Similar to a magnifying glass with handle, the compact hand-held sensor contains extremely sharp needle electrodes for the detection of the induction vector B as well as double-field coils for the vector H. Losses P are derived from the Poynting law. Applied to inner -- or also outer -- core regions, the sensor yields instantaneous computer displays of local H, B, and P.

  14. A loss-based, magnetic field sensor implemented in a ferrofluid infiltrated microstructured polymer optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Candiani, A. [Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion 70013 Greece (Greece); Department of Information Engineering (DII), University of Parma, Parma 43124 (Italy); Argyros, A.; Leon-Saval, S. G.; Lwin, R. [Institute of Photonics and Optical Science (IPOS), School of Physics, The University of Sydney, Sydney (Australia); Selleri, S. [Department of Information Engineering (DII), University of Parma, Parma 43124 (Italy); Pissadakis, S., E-mail: pissas@iesl.forth.gr [Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion 70013 Greece (Greece)

    2014-03-17

    We report an in-fiber magnetic field sensor based on magneto-driven optical loss effects, while being implemented in a ferrofluid infiltrated microstructured polymer optical fiber. We demonstrate that magnetic field flux changes up to 2000 gauss can be detected when the magnetic field is applied perpendicular to the fiber axis. In addition, the sensor exhibits high polarization sensitivity for the interrogated wavelengths, providing the possibility of both field flux and direction measurements. The underlying physical and guidance mechanisms of this sensing transduction are further investigated using spectrophotometric, light scattering measurements, and numerical simulations, suggesting photonic Hall effect as the dominant physical, transducing mechanism.

  15. Effect of the magnetic material on AC losses in HTS conductors in AC magnetic field carrying AC transport current

    Science.gov (United States)

    Wan, Xing-Xing; Huang, Chen-Guang; Yong, Hua-Dong; Zhou, You-He

    2015-11-01

    This paper presents an investigation on the AC losses in several typical superconducting composite conductors using the H-formulation model. A single superconducting strip with ferromagnetic substrate or cores and a stack of coated conductors with ferromagnetic substrates are studied. We consider all the coated conductors carrying AC transport currents and simultaneously exposed to perpendicular AC magnetic fields. The influences of the amplitude, frequency, phase difference and ferromagnetic materials on the AC losses are investigated. The results show that the magnetization losses of single strip and stacked strips have similar characteristics. The ferromagnetic substrate can increase the magnetization loss at low magnetic field, and decrease the loss at high magnetic field. The ferromagnetic substrate can obviously increase the transport loss in stacked strips. The trends of total AC losses of single strip and stacked strips are similar when they are carrying current or exposed to a perpendicular magnetic field. The effect of the frequency on the total AC losses of single strip is related to the amplitude of magnetic field. The AC losses decrease with increasing frequency in low magnetic field region while increase in high magnetic field region. As the phase difference changes, there is a periodic variation for the AC losses. Moreover, when the strip is under only the transport current and magnetic field, the ferromagnetic cores will increase the AC losses for large transport current or field.

  16. Enhanced O2+ loss at Mars due to an ambipolar electric field from electron heating

    Science.gov (United States)

    Ergun, R. E.; Andersson, L. A.; Fowler, C. M.; Woodson, A. K.; Weber, T. D.; Delory, G. T.; Andrews, D. J.; Eriksson, A. I.; McEnulty, T.; Morooka, M. W.; Stewart, A. I. F.; Mahaffy, P. R.; Jakosky, B. M.

    2016-05-01

    Recent results from the MAVEN Langmuir Probe and Waves instrument suggest higher than predicted electron temperatures (Te) in Mars' dayside ionosphere above ~180 km in altitude. Correspondingly, measurements from Neutral Gas and Ion Mass Spectrometer indicate significant abundances of O2+ up to ~500 km in altitude, suggesting that O2+ may be a principal ion loss mechanism of oxygen. In this article, we investigate the effects of the higher Te (which results from electron heating) and ion heating on ion outflow and loss. Numerical solutions show that plasma processes including ion heating and higher Te may greatly increase O2+ loss at Mars. In particular, enhanced Te in Mars' ionosphere just above the exobase creates a substantial ambipolar electric field with a potential (eΦ) of several kBTe, which draws ions out of the region allowing for enhanced escape. With active solar wind, electron, and ion heating, direct O2+ loss could match or exceed loss via dissociative recombination of O2+. These results suggest that direct loss of O2+ may have played a significant role in the loss of oxygen at Mars over time.

  17. Effect of a magnetic field on massive star winds I: mass-loss and velocity for a dipole field

    CERN Document Server

    Bard, Christopher

    2016-01-01

    We generalize the Rigid-Field Hydrodynamic equations to accommodate arbitrary magnetic field topologies, resulting in a new Arbitrary Rigid-Field hydrodynamic (ARFHD) formalism. We undertake a critical point calculation of the steady-state ARFHD equations with a CAK-type radiative acceleration and determine the effects of a dipole magnetic field on the usual CAK mass-loss rate and velocity structure. Enforcing the proper optically-thin limit for the radiative line-acceleration is found to decrease both the mass-loss and wind acceleration, while rotation boosts both properties. We define optically-thin-correction and rotation parameters to quantify these effects on the global mass-loss rate and develop scaling laws for the surface mass-flux as a function of surface colatitude. These scaling laws are found to agree with previous laws derived from magnetohydrodynamic simulations of magnetospheres. The dipole magnetosphere velocity structure is found to differ from a global beta-velocity law, which contradicts a ...

  18. Effect of a magnetic field on massive-star winds - I. Mass-loss and velocity for a dipole field

    Science.gov (United States)

    Bard, Christopher; Townsend, Richard H. D.

    2016-11-01

    We generalize the Rigid-Field Hydrodynamic equations to accommodate arbitrary magnetic field topologies, resulting in a new Arbitrary Rigid-Field Hydrodynamic (ARFHD) formalism. We undertake a critical point calculation of the steady-state ARFHD equations with a CAK-type radiative acceleration and determine the effects of a dipole magnetic field on the usual CAK mass-loss rate and velocity structure. Enforcing the proper optically thin limit for the radiative line-acceleration is found to decrease both the mass-loss and wind acceleration, while rotation boosts both properties. We define optically thin correction and rotation parameters to quantify these effects on the global mass-loss rate and develop scaling laws for the surface mass-flux as a function of surface colatitude. These scaling laws are found to agree with previous laws derived from magnetohydrodynamic simulations of magnetospheres. The dipole magnetosphere velocity structure is found to differ from a global beta-velocity law, which contradicts a central assumption of the previously developed XADM model of X-ray emission from magnetospheres.

  19. Effects of the Electric Field on the Direct Loss Asymmetries on TJ-II

    International Nuclear Information System (INIS)

    The effects of the radial electric fields upon the direct loss asymmetries have been studied for low energy (0.1-1keV)ions. The analysis shows the permanence of the predominant downwards asymmetry that is only slightly modified in the poloidal rotation direction for moderate electric fields. In TJ-II this poloidal rotation is directed towards decreasing poloidal angles for positive (outward) electric fields and the ions drift along the same direction. Nevertheless for very strong fields the lost particles concentrate in the extreme plasma periphery (at the same time that the rate loss decreases strongly) and have no time, any more, to feel the poloidal rotation before escaping. The gaps between the TF coils receive the most of the losses. On the Vacuum Vessel the losses have a very strong concentration along the Hard Core, in particular on the PLT-2 plane plate (the one that is placed down at Phi=0 degree centigree) and a moderate preference for the 2''nd toroidal octant of each period. The poloidal rotation is much less visible than on the plasma border. The resulting power loads are small. (Author)

  20. Model parameter uncertainty analysis for an annual field-scale P loss model

    Science.gov (United States)

    Bolster, Carl H.; Vadas, Peter A.; Boykin, Debbie

    2016-08-01

    Phosphorous (P) fate and transport models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. Because all models are simplifications of complex systems, there will exist an inherent amount of uncertainty associated with their predictions. It is therefore important that efforts be directed at identifying, quantifying, and communicating the different sources of model uncertainties. In this study, we conducted an uncertainty analysis with the Annual P Loss Estimator (APLE) model. Our analysis included calculating parameter uncertainties and confidence and prediction intervals for five internal regression equations in APLE. We also estimated uncertainties of the model input variables based on values reported in the literature. We then predicted P loss for a suite of fields under different management and climatic conditions while accounting for uncertainties in the model parameters and inputs and compared the relative contributions of these two sources of uncertainty to the overall uncertainty associated with predictions of P loss. Both the overall magnitude of the prediction uncertainties and the relative contributions of the two sources of uncertainty varied depending on management practices and field characteristics. This was due to differences in the number of model input variables and the uncertainties in the regression equations associated with each P loss pathway. Inspection of the uncertainties in the five regression equations brought attention to a previously unrecognized limitation with the equation used to partition surface-applied fertilizer P between leaching and runoff losses. As a result, an alternate equation was identified that provided similar predictions with much less uncertainty. Our results demonstrate how a thorough uncertainty and model residual analysis can be used to identify limitations with a model. Such insight can then be used to guide future data collection and model

  1. Altitudinal patterns of Stereocaulon (Lichenized Ascomycota) in China

    Science.gov (United States)

    Huang, Man-Rong

    2010-03-01

    Based on herbarium collections, the altitudinal distribution patterns of six species of the lichen genus Stereocaulon in China were analyzed. Species are elevation-dependent: normal distributions and corresponding empirical formulae were detected for the genus and S. japonicum and S. paschale, the species distributed in low elevation areas, and log-normal distributions detected for S. sorediiferum and S. tomentosum, the species in medium elevation areas, while S. pomiferum and S. myriocarpum, the species in high elevation areas, appear to be irregularly distributed according to altitude. Such formulae should prove valuable for biological conservation practices.

  2. Hemianopic Field Loss in an Infant Post CVA: A Case Study

    Directory of Open Access Journals (Sweden)

    Benjamin J. Konynenbelt, OD

    2015-09-01

    Full Text Available Background: Visual field loss is a common result of cerebrovascular accidents (CVAs, with the location of the vascular incident correlating with the location and extent of visual field loss. Many CVA patients also experience hemi-spatial visual neglect, lacking attention to of one side of space. Those suffering from these conditions may find simple tasks such as reading, self-grooming, and navigating common areas to range from difficult to nearly impossible. Although CVAs are more common in the elderly population, the following presents a case of an infant suffering a CVA shortly after birth. This provides a unique case of a patient facing a diverse set of challenges while in a highly plastic stage of neural development. Case: An 11-month-old female born prematurely with a history of CVA presented for a visual function consult. Her father expressed concern for useful vision in her left eye and was seeking further evaluation and therapeutic options. Examination revealed inattention to the left visual field with no fixation preference toward either eye. Ocular motility was limited in upgaze, but the patient had full motility in both left and right gazes. There was a positive OKN response to 1.6 cycles/deg (~20/400 Snellen equivalent in each eye. Discussion: An infant suffering field loss faces different challenges than an adult. Techniques to evaluate and treat the patient may be adapted to maximize the patient’s visual performance.

  3. Field Evaluation of Cereal Combine Harvesters Processing Losses on JD-955 and JD-1165 Combines Equipped with Grain Loss Monitor

    Directory of Open Access Journals (Sweden)

    M.R Mostofi Sarkari

    2014-09-01

    Full Text Available Grain loss monitors are installed on combine harvester and make it possible to measure grain loss on different parts of the combine. The instrument permits the operator to adjust a proper ground speed to keep grain loss within an acceptable range. In this study a loss monitoring system was implemented to measure grain losses continuously on straw walker and sieves. Two grain loss monitors (KEE and TeeJet were installed behind the straw walker and the sieves of JD-955 and JD-1165 combine harvesters. Harvesting performance parameters such as combine total and processing losses were then measured. To evaluate the precision and accuracy of the instruments, the measured and monitored losses were compared and investigated. The results of a two-year research showed that the average processing loss of the combine harvesters with 10-12% grain moisture content and 750 rpm drum speed was 0.82% which is whitin the acceptable range recommended by ASAE Standard No. S343.3. Furthermore, there was no significant difference between the measured and monitored values of processing loss.

  4. Flood control and loss estimation for paddy field at midstream of Chao Phraya River Basin, Thailand

    Science.gov (United States)

    Cham, T. C.; Mitani, Y.

    2015-09-01

    2011 Thailand flood has brought serious impact to downstream of Chao Phraya River Basin. The flood peak period started from August, 2011 to the end of October, 2011. This research focuses on midstream of Chao Phraya River Basin, which is Nakhon Sawan area includes confluence of Nan River and Yom River, also confluence of Ping River and Nan River. The main purpose of this research is to understand the flood generation, estimate the flood volume and loss of paddy field, also recommends applicable flood counter measurement to ease the flood condition at downstream of Chao Phraya River Basin. In order to understand the flood condition, post-analysis is conducted at Nakhon Sawan. The post-analysis consists of field survey to measure the flood marks remained and interview with residents to understand living condition during flood. The 2011 Thailand flood generation at midstream is simulated using coupling of 1D and 2D hydrodynamic model to understand the flood generation during flood peak period. It is calibrated and validated using flood marks measured and streamflow data received from Royal Irrigation Department (RID). Validation of results shows good agreement between simulated result and actual condition. Subsequently, 3 scenarios of flood control are simulated and Geographic Information System (GIS) is used to assess the spatial distribution of flood extent and reduction of loss estimation at paddy field. In addition, loss estimation for paddy field at midstream is evaluated using GIS with the calculated inundation depth. Results show the proposed flood control at midstream able to minimize 5% of the loss of paddy field in 26 provinces.

  5. Towards identifying the mechanisms underlying field-aligned edge-loss of HHFW power on NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, R. J. [Princeton Plasma Physics Laboratory (PPPL); Ahn, Joonwook [ORNL; Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Bertelli, Nicola [Princeton Plasma Physics Laboratory (PPPL); Diallo, A. [Princeton Plasma Physics Laboratory (PPPL); Gerhardt, S. [Princeton Plasma Physics Laboratory (PPPL); Gray, T. K. [Oak Ridge National Laboratory (ORNL); Green, David L [ORNL; Jaeger, E. F. [XCEL; Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Jaworski, M. A. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); McLean, Adam G [ORNL; Maingi, Rajesh [ORNL; Phillips, C. K. [Princeton Plasma Physics Laboratory (PPPL); Podesta, M. [Princeton Plasma Physics Laboratory (PPPL); Ryan, Philip Michael [ORNL; Sabbagh, S. A. [Columbia University; Scotti, F. [Princeton Plasma Physics Laboratory (PPPL); Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)

    2013-01-01

    Fast-wave heating will be a major heating scheme on ITER, as it can heat ions directly and is relatively unaffected by the large machine size unlike neutral beams. However, fast-wave interactions with the plasma edge can lead to deleterious effects such as, in the case of the high-harmonic fast-wave (HHFW) system on NSTX, large losses of fast-wave power in the scrape off layer (SOL) under certain conditions. In such scenarios, a large fraction of the lost HHFW power is deposited on the upper and lower divertors in bright spiral shapes. The responsible mechanism(s) has not yet been identified but may include fast-wave propagation in the scrape off layer, parametric decay instability, and RF currents driven by the antenna reactive fields. Understanding and mitigating these losses is important not only for improving the heating and current-drive on NSTX-Upgrade but also for understanding fast-wave propagation across the SOL in any fast-wave system. This talk summarizes experimental results demonstrating that the flow of lost HHFW power to the divertor regions largely follows the open SOL magnetic field lines. This lost power flux is relatively large close to both the antenna and the last closed flux surface with a reduced level in between, so the loss mechanism cannot be localized to the antenna. At the same time, significant losses also occur along field lines connected to the inboard edge of the bottom antenna plate. The power lost within the spirals is roughly estimated, showing that these field-aligned losses to the divertor are significant but may not account for the total HHFW loss. To elucidate the role of the onset layer for perpendicular fast-wave propagation with regards to fast-wave propagation in the SOL, a cylindrical cold-plasma model is being developed. This model, in addition to advanced RF codes such as TORIC and AORSA, is aimed at identifying the underlying mechanism(s) behind these SOL losses, to minimize their effects in NSTX-U, and to predict

  6. Altitudinal variation in bumble bee (Bombus) critical thermal limits.

    Science.gov (United States)

    Oyen, K Jeannet; Giri, Susma; Dillon, Michael E

    2016-07-01

    Organism critical thermal limits are often tightly linked to current geographic distribution and can therefore help predict future range shifts driven by changing environmental temperatures. Thermal tolerance of diverse organisms often varies predictably with latitude, with upper thermal limits changing little and lower thermal limits decreasing with latitude. Despite similarly steep gradients in environmental temperatures across altitude, few studies have investigated altitudinal variation in critical thermal limits. We estimated critical thermal minimum (CTmin), critical thermal maximum (CTmax) and recovery temperature (Trec) by tracking righting response of three bumble bee species during thermal ramps: Bombus huntii collected from 2180m asl, and Bombus bifarius and Bombus sylvicola collected from 3290m asl in Wyoming, USA. Overall, larger bees could tolerate more extreme temperatures, likely due to a thermal inertia driven lag between core body temperatures and air temperatures. Despite their smaller size, high altitude bumble bees tolerated colder air temperatures: they had ~1°C lower CTmin and recovered from cold exposure at ~3-4°C lower air temperatures. Conversely, low altitude bees tolerated ~5°C hotter air temperatures. These altitudinal differences in thermal tolerance parallel differences in average daily minimum (1.2°C) and maximum (7.5°C) temperatures between these sites. These results provide one of the few measurements of organism thermal tolerance across altitude and the first evidence for geographical differences in tolerance of temperature extremes in heterothermic bumble bees. PMID:27264888

  7. Minimalist coupled evolution model for stellar X-ray activity, rotation, mass loss, and magnetic field

    Science.gov (United States)

    Blackman, Eric G.; Owen, James E.

    2016-05-01

    Late-type main-sequence stars exhibit an X-ray to bolometric flux ratio that depends on {tilde{R}o}, the ratio of rotation period to convective turnover time, as {tilde{R}o}^{-ζ } with 2 ≤ ζ ≤ 3 for {tilde{R}o} > 0.13, but saturates with |ζ| rates and X-ray activity. The unsaturated stars have magnetic fields and rotation speeds that scale roughly with the square root of their age, though possibly flattening for stars older than the Sun. The connection between faster rotators, stronger fields, and higher activity has been established observationally, but a theory for the unified time-evolution of X-ray luminosity, rotation, magnetic field and mass loss that captures the above trends has been lacking. Here we derive a minimalist holistic framework for the time evolution of these quantities built from combining a Parker wind with new ingredients: (1) explicit sourcing of both the thermal energy launching the wind and the X-ray luminosity via dynamo produced magnetic fields; (2) explicit coupling of X-ray activity and mass-loss saturation to dynamo saturation (via magnetic helicity build-up and convection eddy shredding); (3) use of coronal equilibrium to determine how magnetic energy is divided into wind and X-ray contributions. For solar-type stars younger than the Sun, we infer conduction to be a subdominant power loss compared to X-rays and wind. For older stars, conduction is more important, possibly quenching the wind and reducing angular momentum loss. We focus on the time evolution for stars younger than the Sun, highlighting what is possible for further generalizations. Overall, the approach shows promise towards a unified explanation of all of the aforementioned observational trends.

  8. A quantum optical description of losses in ring resonators based on field operator transformations

    OpenAIRE

    Alsing, Paul M.; Hach III, Edwin E.; Tison, Christopher C.; Smith, A. Matthew

    2016-01-01

    In this work we examine loss in ring resonator networks from an "operator valued phasor addition" approach (or OVPA approach) which considers the multiple transmission and cross coupling paths of a quantum field traversing a ring resonator coupled to one or two external waveguide buses. We demonstrate the consistency of our approach by the preservation of the operator commutation relation of the out-coupled bus mode. We compare our results to those obtained from the conventional quantum Lange...

  9. Effects of stator bending on pressure field and loss of transonic turbine stage

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; ZHOU Xun; WANG Zhong-qi

    2009-01-01

    To study effects of the upstream flow field changing on the downstream flow field of transonic turbine, different three-dimensional bowed blades, which are the stator blades of transonic turbine stage, were designed in this paper. And then numerical calculations were carried out. The effects on downstream flow field were studied and analyzed in detail. Results show that, at the middle of stator blades, although the increasing Mach number causes the increase of shock-wave strength and friction, the middle flow field of downstream rotors is improved obviously. It is an important change in transonic condition. This causes the loss of the rotor's middie part decreased greatly. Correspondingly, efficiency of the whole transonic stage can be increased.

  10. Minimalist coupled evolution model for stellar x-ray activity, rotation, mass loss, and magnetic field

    CERN Document Server

    Blackman, Eric G

    2015-01-01

    Late-type main sequence stars exhibit an x-ray to bolometric flux that depends on the Corolis number $Co$ (product of convective turnover time and angular rotation speed) as $Co^{\\zeta}$ with $2\\le \\zeta \\le 3$ for $Co > 1$. Stars in the unsaturated regime also obey the Skumanich law--- their rotation speeds scale inversely with square root of their age. The associated stellar magnetic field strengths follow a similar decrease with age. While the connection between faster rotators, stronger fields, and higher activity has been well established observationally, a basic theory for the time evolution of x-ray luminosity, rotation, magnetic field and mass loss been lacking. Here we offer a minimalist model for the time evolution of these quantities built from combining a Parker wind with several new ingredients: (1) explicit sourcing of both the thermal energy launching the wind and the x-ray luminosity via dynamo produced magnetic fields; (2) explicit coupling of x-ray activity and mass loss saturation to dynamo...

  11. Extremely narrow resonances, giant sensitivity and field enhancement in low-loss waveguide sensors

    Science.gov (United States)

    Nesterenko, D. V.; Hayashi, S.; Sekkat, Z.

    2016-06-01

    Low-loss waveguides (WGs), which support excitation of waveguide modes (WMs), are based on a dielectric WG separated from an absorptive film by a low-index dielectric spacer layer. We perform numerical and analytical study of the impact of the losses imposed to the WG in a planar sensing structure in the Kretschmann configuration on the resonance properties of the excitation. We demonstrate that the loss degree of the WMs can be controlled by the thickness of the spacer layer for both s and p polarizations. Extremely narrow resonances are discovered in the reflectivity spectra due to excitation of the low-loss WMs, and the maximum of the estimated sensitivity by intensity is found to be of 105-fold higher as compared to the conventional surface plasmon and WG-coupled surface plasmon sensors. We reveal the giant field intensity enhancement of 107-fold on the surface of the sensing structure in aqueous sensing media that can provide stronger fluorescence intensity at lower sample volumes for fluorescent labeling sensing.

  12. Field distribution and power loss assessment in conductive rod cores exhibiting hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    Adly, A.A.; Mahfouz, A.A.; Mahgoub, O.A.; Zeid, S.A. [Cairo Univ., Giza (Egypt). Electric Power and Machines Dept.

    1996-09-01

    Recently, a new numerical approach for core loss evaluation in media exhibiting hysteresis has been proposed for relatively long conductive rods, subject to surface excitation along their azimuthal direction. In this approach, the Crank-Nicolson finite-difference technique is used, while exact media properties are taken into account by utilizing Preisach-type models of hysteresis. The purpose of this paper is to provide some experimental verification of the aforementioned approach. Accuracy of this approach has been assessed for a 2 cm diameter, 25 cm long iron alloy rod. Voltage wave-forms and core losses corresponding to some controlled applied field frequencies and amplitudes were experimentally deduced. For every experimentally considered excitation amplitude and frequency, computations were performed using the developed approach. Comparisons have demonstrated good quantitative agreements between the experimentally measured and computed results. Sample comparison results are given in the paper.

  13. Altitudinal dependence of meteor radio afterglows measured via optical counterparts

    CERN Document Server

    Obenberger, K S; Dowell, J D; Schinzel, F K; Stovall, K; Sutton, E K; Taylor, G B

    2016-01-01

    Utilizing the all-sky imaging capabilities of the LWA1 radio telescope along with a host of all-sky optical cameras, we have now observed 44 optical meteor counterparts to radio afterglows. Combining these observations we have determined the geographic positions of all 44 afterglows. Comparing the number of radio detections as a function of altitude above sea level to the number of expected bright meteors we find a strong altitudinal dependence characterized by a cutoff below $\\sim$ 90 km, below which no radio emission occurs, despite the fact that many of the observed optical meteors penetrated well below this altitude. This cutoff suggests that wave damping from electron collisions is an important factor for the evolution of radio afterglows, which agrees with the hypothesis that the emission is the result of electron plasma wave emission.

  14. Transient loss of plasma from a theta pinch having an initially reversed magnetic field

    International Nuclear Information System (INIS)

    The results of an experimental study of the transient loss of plasma from a 25-cm-long theta pinch initially containing a reversed trapped magnetic field are presented. The plasma, amenable to MHD analyses, was a doubly ionized helium plasma characterized by an ion density N/sub i/ = 2 x 1016 cm-3 and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 1016 cm-3 and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil

  15. Transient loss of plasma from a theta pinch having an initially reversed magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Heidrich, J. E.

    1981-01-01

    The results of an experimental study of the transient loss of plasma from a 25-cm-long theta pinch initially containing a reversed trapped magnetic field are presented. The plasma, amenable to MHD analyses, was a doubly ionized helium plasma characterized by an ion density N/sub i/ = 2 x 10/sup 16/ cm/sup -3/ and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10/sup 16/ cm/sup -3/ and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil.

  16. Climate change and frog calls: long-term correlations along a tropical altitudinal gradient

    OpenAIRE

    Narins, Peter M.; Meenderink, Sebastiaan W. F.

    2014-01-01

    Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration....

  17. Binocular Glaucomatous Visual Field Loss and Its Impact on Visual Exploration - A Supermarket Study

    Science.gov (United States)

    Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as “passed” or “failed” with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p<0.001). Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD) area than patients who failed (t-test, p<0.05). According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a “time-effective” compensatory mechanism during the present supermarket task. PMID:25162522

  18. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Science.gov (United States)

    Sippel, Katrin; Kasneci, Enkelejda; Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001). Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD) area than patients who failed (t-test, p < 0.05). According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  19. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Directory of Open Access Journals (Sweden)

    Katrin Sippel

    Full Text Available Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii to identify factors influencing the performance, and (iii to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP, and ten healthy-sighted control subjects (GC were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item. Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001. Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD area than patients who failed (t-test, p < 0.05. According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  20. Detailed modelling of screening currents, their magnetic field and AC loss in coated conductor magnets containing up to 40000 turns

    OpenAIRE

    Pardo, Enric

    2016-01-01

    Screening currents caused by varying magnetic fields degrade the homogeneity and stability of the magnetic fields created by $RE$BCO coated conductor coils. They are responsible for the AC loss, which is also important for other power applications containing windings. Since real magnets contain coils exceeding 10000 turns, accurate modeling tools for this number of turns are necessary for magnet design. This article presents a fast numerical method to model coils with no loss of accuracy. We ...

  1. A Novel Scanning Near-Field Microwave Microscope Capable of High Resolution Loss Imaging

    Science.gov (United States)

    Imtiaz, Atif

    2005-03-01

    To study novel physics in condensed matter and materials science, experimental techniques need to be pushed for better sensitivity and higher spatial resolution. Classical techniques of probing the high frequency electrical properties of materials are limited in resolution to the wavelength of the incident electromagnetic wave. We report here a novel near-field microwave microscope to image materials contrast, with 2.5 nm spatial resolution in capacitance. Our objective is to improve the spatial resolution in local loss imaging. We will present evidence of sheet resistance contrast in a Boron-doped Silicon sample on sub- micron length scales. We will present quantitative analysis of the data on the Boron-doped Silicon sample in light of evanescent wave model of the microscope that we have developed. In addition, the probe to sample interaction on nanometer length scales will be discussed [1]. This work has been supported by an NSF IMR Grant DMR-9802756, and the University of Maryland/Rutgers NSF-MRSEC through the Near Field Microwave Microscope Shared Experimental Facility Grant DMR-00-80008. [1] Atif Imtiaz, Marc Pollak, Steven M. Anlage, John D. Barry and John Melngailis, ``Near-Field Microwave Microscopy on nanometer length scales'', to be published in J. Appl. Phys. (Feb. 1, 2005).

  2. Loss mechanisms and back surface field effect in photon enhanced thermionic emission converters

    Science.gov (United States)

    Segev, Gideon; Rosenwaks, Yossi; Kribus, Abraham

    2013-07-01

    Photon Enhanced Thermionic Emission (PETE) solar converters are based on emission of energetic electrons from a semiconductor cathode that is illuminated and heated with solar radiation. By using a semiconductor cathode, photo generated electrons enable high electron emission at temperatures much lower than the common range for thermionic emitters. Simple models show that PETE conversion can theoretically reach high efficiency, for example, above 40% at concentration of 1000 suns. In this work, we present a detailed one-dimensional model of PETE conversion, accounting for recombination mechanisms, surface effects, and spatial distribution of potential and carrier concentration. As in the previous PETE models, negative space charge effects, photon recycling, and temperature gradients are not considered. The conversion efficiency was calculated for Si and GaAs based cathodes under a wide range of operating conditions. The calculated efficiencies are lower than predictions of previous zero-dimensional models. We analyze the loss mechanisms and show that electron recombination at the cathode contact is a significant loss. An electron-blocking junction at the cathode back contact is therefore essential for achieving high efficiency. The predicted efficiencies for Si and GaAs cathodes with homo-junction back surface field layers are both around 31%, but with more favorable assumptions on the contact structure, it may be near 40%. The analysis leads to important conclusions regarding the selection of cathode material and back surface junction configuration.

  3. Evaluation and selection of soil amendments for field testing to reduce P losses

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, G.A.; Brinton, S.; Silveira, M.L. [University of Florida, Gainesville, FL (United States). Dept. of Soil & Water Science

    2005-07-01

    The effectiveness of chemical amendments in reducing P losses from manure impacted Florida soil was evaluated using a variety of protocols, including total elemental analysis, short-term laboratory equilibrations, column leaching experiments, and simulated rainfall studies. Amendments used included: two Fe-humates (a Fe-water treatment residual (WTR) and a titanium-mine waste), two Al-WTRs, one Ca-WTR, a coal combustion slag, a Si-rich material (Pro-Sil), a Leonardite material (dinoSoil), and two agricultural materials (lime and gypsum). In equilibration studies, Al-WTRs were the most effective at sorbing P, while Fe-humate sorbed the least P of all treatments. Other amendments effectively reduced soluble P, but increased suspension pH and electrical conductivity (EC) to an extent expected to adversely affect plant growth. Gypsum was the most effective amendment in reducing P leaching in small column studies. DinoSoil treatment significantly altered the soil hydraulic properties, yielding the greatest runoff volumes in a simulated rainfall study. Total P loss (runoff + leachate) was largely determined by the leaching component, and was essentially all soluble reactive phosphorus (SRP) for both bare and grassed soil surfaces. AD treatments reduced runoff SRP compared to the control. Amendment effects in the grassed rainfall study (dominated by leaching) were inconsistent with results from the small column leaching study, possibly due to the different hydraulic conditions and kinetic factors involved in the two studies. The Al-WTRs amendments were recommended for field evaluation.

  4. Embolic and nonembolic transient monocular visual field loss: a clinicopathologic review.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Hu, Han-Hwa; Plant, Gordon T

    2013-01-01

    Transient monocular blindness and amaurosis fugax are umbrella terms describing a range of patterns of transient monocular visual field loss (TMVL). The incidence rises from ≈1.5/100,000 in the third decade of life to ≈32/100,000 in the seventh decade of life. We review the vascular supply of the retina that provides an anatomical basis for the types of TMVL and discuss the importance of collaterals between the external and internal carotid artery territories and related blood flow phenomena. Next, we address the semiology of TMVL, focusing on onset, pattern, trigger factors, duration, recovery, frequency-associated features such as headaches, and on tests that help with the important differential between embolic and non-embolic etiologies.

  5. Effects of Optical Loss Factors on Heliostat Field Layout for Beam-Down Solar Concentrating Systems

    Science.gov (United States)

    Utamura, Motoaki; Takamatsu, Tadahiko; Yuasa, Minoru; Kajita, Rina; Yamamoto, Takashi

    A methodology to give an optimal layout of a group of heliostats has been developed for beam-down concentrating solar tower systems. Given the maximum solar power together with optical parameters, the method determines an optimal configuration of a heliostat field around a tower. Various optical losses such as cosine factor, shadowing and blocking at heliostats are considered in the calculation. Furthermore, spillage at the receiver is taken into account due to the spread of light caused by the effects of a finite solar disk, flat facet and various stochastic errors in optical hardware and control. It is found the effect of spillage becomes significant at heliostats from the tower at the distance farther than four times of upper focus height of the reflector when receiver diameter is one fifteenth of the height and dominates the configuration of the optimal heliostat layout.

  6. Reverse altitudinal cline in cold hardiness among Erebia butterflies.

    Science.gov (United States)

    Vrba, Pavel; Konvicka, Martin; Nedved, Oldrich

    2012-01-01

    There is strong evidence for a shifting of range boundaries by many temperate butterfly species to higher altitudes and latitudes. Climate change represents a potential threat to mountain fauna. Nevertheless, information on ecophysiological limits of individual species is scarce. We studied the lower thermal limits of four species representing the prevailingly mountain Holarctic butterfly genus Erebia. We measured the cold tolerance of hibernating larvae, namely the supercooling point (SCP) and the lower lethal temperature (LLT). Three mountain species were freeze avoiding, with various levels of SCP (-8 to -22 degree C), and LLT close to SCP. The only exception was lowland E. medusa, whose caterpillars were freeze tolerant with LLT (-21 degree C) slightly below its SCP (-17 degree C). Surprisingly, LLT was highest in the alpine E. tyndarus and lowest in E. medusa inhabiting lower altitudes with higher mean winter temperatures. We explain the observed reversed altitudinal cline in cold hardiness by the buffering function of snow cover in the hibernacula of caterpillars that is strong at high mountains but irregular, unpredictable and thus unreliable in lowlands. PMID:22987236

  7. Temperature is the key to altitudinal variation of phenolics in Arnica montana L. cv. ARBO.

    Science.gov (United States)

    Albert, Andreas; Sareedenchai, Vipaporn; Heller, Werner; Seidlitz, Harald K; Zidorn, Christian

    2009-05-01

    Plants in alpine habitats are exposed to many environmental stresses, in particular temperature and radiation extremes. Recent field experiments on Arnica montana L. cv. ARBO indicated pronounced altitudinal variation in plant phenolics. Ortho-diphenolics increased with altitude compared to other phenolic compounds, resulting in an increase in antioxidative capacity of the tissues involved. Factors causing these variations were investigated by climate chamber (CC) experiments focusing on temperature and ultraviolet (UV)-B radiation. Plants of A. montana L. cv. ARBO were grown in CCs under realistic climatic and radiation regimes. Key factors temperature and UV-B radiation were altered between different groups of plants. Subsequently, flowering heads were analyzed by HPLC for their contents of flavonoids and caffeic acid derivatives. Surprisingly, increased UV-B radiation did not trigger any change in phenolic metabolites in Arnica. In contrast, a pronounced increase in the ratio of B-ring ortho-diphenolic (quercetin) compared to B-ring monophenolic (kaempferol) flavonols resulted from a decrease in temperature by 5 degrees C in the applied climate regime. In conclusion, enhanced UV-B radiation is probably not the key factor triggering shifts in the phenolic composition in Arnica grown at higher altitudes but rather temperature, which decreases with altitude.

  8. [A 65-year-old woman with progressive loss of vision and visual field defects].

    Science.gov (United States)

    Furuya, Tsuyoshi; Namihira, Tomoo; Yamazaki, Shigetaka; Mori, Hideo; Hattori, Nobutaka; Mizuno, Yoshikuni

    2003-01-01

    We report a 65-year-old Japanese lady who suffered from progressive loss of vision and visual field defect. She was well until her 61 years of the age in November of 1999, when she was found to have bitemporal hemianopsia. A small enhancing mass lesion was found in the chiasmatic region. She was treated with steroid and she noted marked improvement in her visual field defects. In August of 2000, she noted disturbance of gait. Cranial MRI revealed a mass in the right midbrain extending into the hypothalamic and thalamic regions. She was again treated with steroid with marked improvement. However, in November of 2001, she started to show somnolence and diabetes insipidus. She was treated with steroid, nasal desmopressin, and insulin for her steroid induced diabetes mellitus. Cranial CT scan showed a large enhancing lesion involving the entire midbrain, hypothalamus, and the thalamic regions. She developed respiratory arrest on July 15, 2001 and was pronounced dead. She was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had a primary malignant lymphoma of the brain. Clinical diagnosis in the early stage of her disease was neurosarcoidosis. Post-mortem examination revealed a mass continuously involving the pons, midbrain, hypothalamus, thalamus, and the putamen. The optic chiasm was enlarged. By histologic examination, the mass consisted of dense medium sized tumor cells. Immunohistologic observation revealed that the tumor cells were B-cell type malignant lymphoma. No tumor cells were found in the systemic organs. PMID:12649905

  9. First Measurements of the Unique Influence of Spin on the Energy Loss of Ultrarelativistic Electrons in Strong Electromagnetic Fields

    Science.gov (United States)

    Kirsebom, K.; Mikkelsen, U.; Uggerhøj, E.; Elsener, K.; Ballestrero, S.; Sona, P.; Vilakazi, Z. Z.

    2001-07-01

    Although some authors have claimed that the effect is not detectable, we show experimentally for the first time that as the quantum parameter χ grows beyond 1, an increasingly large part of the hard radiation emitted arises from the spin of the electron. Results for the energy loss of electrons in the energy range 35-243 GeV incident on a W single crystal are presented. Close to the axial direction the strong electromagnetic fields induce a radiative energy loss which is significantly enhanced compared to incidence on an amorphous target. In such continuously strong fields, the radiation process is highly nonperturbative for ultrarelativistic particles and a full quantum description is needed. The remarkable effect of spin flips and the energy loss is connected to the presence of a field comparable in magnitude to the Schwinger critical field, E0 = m2c3/eħ, in the rest frame of the emitting electron.

  10. Driving with homonymous visual field loss: a review of the literature.

    Science.gov (United States)

    Bowers, Alex R

    2016-09-01

    Driving is an important rehabilitation goal for patients with homonymous field defects (HFDs); however, whether or not people with HFDs should be permitted to drive is not clear. Over the last 15 years, there has been a marked increase in the number of studies evaluating the effects of HFDs on driving performance. This review of the literature provides a much-needed summary for practitioners and researchers, addressing the following topics: regulations pertaining to driving with HFDs, self-reported driving difficulties, pass rates in on-road tests, the effects of HFDs on lane position and steering stability, the effects of HFDs on scanning and detection of potential hazards, screening for potential fitness to drive, evaluating practical fitness to drive and the efficacy of interventions to improve driving of persons with HFDs. Although there is clear evidence from on-road studies that some people with HFDs may be rated as safe to drive, others are reported to have significant deficits in skills important for safe driving, including taking a lane position too close to one side of the travel lane, unstable steering and inadequate viewing (scanning) behaviour. Driving simulator studies have provided strong evidence of a wide range in compensatory scanning abilities and detection performance, despite similar amounts of visual field loss. Conventional measurements of visual field extent (in which eye movements are not permitted) do not measure such compensatory abilities and are not predictive of on-road driving performance. Thus, there is a need to develop better tests to screen people with HFDs for visual fitness to drive. We are not yet at a point where we can predict which HFD patient is likely to be a safe driver. Therefore, it seems only fair to provide an opportunity for individualised assessments of practical fitness to drive either on the road and/or in a driving simulator. PMID:27535208

  11. Altitudinal and seasonal variations in the diet of Japanese macaques in Yakushima.

    Science.gov (United States)

    Hanya, Goro; Noma, Naohiko; Agetsuma, Naoki

    2003-01-01

    Altitudinal and seasonal variations in the diet of Japanese macaques in Yakushima, southwestern Japan, were studied for 2 years by means of fecal analysis. The altitudinal range of fecal samples collected was 30 m to 1,203 m above sea level, and it was divided into three zones: low-zone forest (0-399 m), middle-zone forest (400-799 m), and high-zone forest (800 m-1,230 m). There was a considerable altitudinal and seasonal variation in the macaques' diet. Seed/fruit and animal matter were eaten more in the lower zones, whereas more fiber and fungi were consumed in the higher zones. In all of the zones, they ate seed/fruits the most in autumn (September-November) and the least in spring (March-April). They ate fibrous food the most in spring and the least in autumn. Macaques relied on seed/fruits heavily in the lower zone for a longer period than in the higher zones. Macaques in the high-zone forest ate almost no seed/fruit foods from March to May. Altitudinal variations in availability of seed/fruit foods seem to have influenced the altitudinal variations in diet. Total basal area of seed/fruit-food trees, species richness of seed/fruit-foods, main seed/fruit-food types available, and annual fleshy-fruit production all decreased with increasing altitude. Both interannual variation and annual cyclicity of diet were found in all zones.

  12. Denitrification Losses and N2O Emissions from Nitrogen Fertilizer Applied to a Vegetable Field

    Institute of Scientific and Technical Information of China (English)

    CAO Bing; He Fa-Yun; Xu Qiu-Ming; Yin Bin; CAI Gui-Xin

    2006-01-01

    A field experiment was conducted on Chinese cabbage (Brassica campestris L. ssp. pekinensis (Lour.) Olsson) in a Nanjing suburb in 2003. The experiment included 4 treatments in a randomized complete block design with 3 replicates: zero chemical fertilizer N (CK); urea at rates of 300 kg N ha-1 (U300) and 600 kg N ha-1 (U600), both as basal and two topdressings; and polymer-coated urea at a rate of 180 kg N ha-1 (PCU180) as a basal application. The acetylene inhibition technique was used to measure denitrification (N2 + N2O) from intact soil cores and N2O emissions in the absence of acetylene. Results showed that compared to CK total denitrification losses were significantly greater (P ≤ 0.05) in the PCU180, U300, and U600 treatments, while N2O emissions in the U300 and U600 treatments were significantly higher (P ≤ 0.05) than CK. In the U300 and U600 treatments peaks of denitrification and N2O emission were usually observed after N application. In the polymer-coated urea treatment (PCU180) during the period 20 to 40 days after transplanting, higher denitrification rates and N2O fluxes occurred. Compared with urea, polymer-coated urea did not show any effect on reducing denitrification losses and N2O emissions in terms of percentage of applied N. As temperature gradually decreased from transplanting to harvest, denitrification rates and N2O emissions tended to decrease. A significant (P ≤ 0.01) positive correlation occurred between denitrification (r = 0.872) or N2O emission (r = 0.781) flux densities and soil temperature in the CK treatment with a stable nitrate content during the whole growing season.

  13. Nutrient addition modifies phosphatase activities along an altitudinal gradient in a tropical montane forest in Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Karla eDietrich

    2016-02-01

    Full Text Available Atmospheric nutrient deposition and climate change are expected to endanger the diversity of tropical forest ecosystems. Nitrogen (N deposition might influence nutrient fluxes beyond the N cycle by a concomitant increased demand for other nutritional elements such as phosphorus (P. Organisms might respond to the increased P demand by enhanced activity of enzymes involved in releasing inorganic P from organic matter (OM. Our aims were to assess the effect of i climate shifts (approximated by an altitudinal gradient, and ii nutrient addition (N, P, N+P on phosphatase activity (PA in organic layer and mineral soil of a tropical montane rainforest in Southern Ecuador. A nutrient manipulation experiment (NUMEX was set up along an altitudinal gradient (1000, 2000, and 3000 m a.s.l.. We determined PA and inorganic and total P concentrations. PA at 1000 m was significantly lower (mean ± standard error: 48 ± 20 µmol p-NP g-1 dm h-1 as compared to 2000 m and 3000 m (119 ± 11 and 137 ± 19, respectively. One explanation might be that very rapid decomposition of OM at 1000 m results in very thin organic layers reducing the stabilization of enzymes and thus, resulting in leaching loss of enzymes under the humid tropical climate. We found no effect of N addition on PA neither in the organic layer nor in mineral soil, probably because of the low nutrient addition rates that showed ambiguous results so far on productivity measures as a proxy for P demand. In the organic layers of P and N+P treatments, we found decreased PA and increased concentrations of inorganic P. This indicates that the surplus of inorganic P reduced the biosynthesis of phosphatase enzymes. PA in megadiverse montane rainforests is likely to be unaffected by increased atmospheric N deposition but reduced upon atmospheric P deposition.

  14. Do American dippers obtain a survival benefit from altitudinal migration?

    Directory of Open Access Journals (Sweden)

    David J Green

    Full Text Available Studies of partial migrants provide an opportunity to assess the cost and benefits of migration. Previous work has demonstrated that sedentary American dippers (residents have higher annual productivity than altitudinal migrants that move to higher elevations to breed. Here we use a ten-year (30 period mark-recapture dataset to evaluate whether migrants offset their lower productivity with higher survival during the migration-breeding period when they occupy different habitat, or early and late-winter periods when they coexist with residents. Mark-recapture models provide no evidence that apparent monthly survival of migrants is higher than that of residents at any time of the year. The best-supported model suggests that monthly survival is higher in the migration-breeding period than winter periods. Another well-supported model suggested that residency conferred a survival benefit, and annual apparent survival (calculated from model weighted monthly apparent survival estimates using the Delta method of residents (0.511 ± 0.038SE was slightly higher than that of migrants (0.487 ± 0.032. Winter survival of American dippers was influenced by environmental conditions; monthly apparent survival increased as maximum daily flow rates increased and declined as winter temperatures became colder. However, we found no evidence that environmental conditions altered differences in winter survival of residents and migrants. Since migratory American dippers have lower productivity and slightly lower survival than residents our data suggests that partial migration is likely an outcome of competition for limited nest sites at low elevations, with less competitive individuals being forced to migrate to higher elevations in order to breed.

  15. Field Loss Accounted Design and Simulation of a Stand Alone Photovoltaic System

    Directory of Open Access Journals (Sweden)

    E. Suresh Kumar

    2012-01-01

    Full Text Available The performance of a photovoltaic system (PV can be characterised by many parameters like latitude , ambient temperature, module temperature, long term degradation, irradiance , wind speed, wind direction, air gap between modules, dust, rainfall, corrosion, water vapour intrusion, humidity, mechanical load, salt mist, partial shading, summer-winter climate change, clearness of sky, ageing and component derating, panel orientation and shading, inverter sizing, accuracy of ratings, impact of actual operating conditions on equipment performance, equipment reliability and durability. The use of appropriate performance parameters facilitates the comparison of photovoltaic (PV systems that may differ with respect to design, technology, or geographic location.Further electrical derating factors such as mismatch, component derating, wiring losses, circuit derating also causes reduced PV performance. The goal of a stand-alone system designer is to assure customer satisfaction by providing a welldesigned, durable system with a 20+ year life expectancy. This depends on sound design, specification and procurement of quality components, good engineering and installation practices. This paper describes the design of a stand alone PV system for the geographic location, Kolkata in India, with field lossconsiderations and the simulation of the system using PVsyst, asoftware package for the study, sizing, simulation and data analysisof a complete PV systems.

  16. Species richness and trait composition of butterfly assemblages change along an altitudinal gradient.

    Science.gov (United States)

    Leingärtner, Annette; Krauss, Jochen; Steffan-Dewenter, Ingolf

    2014-06-01

    Species richness patterns along altitudinal gradients are well-documented ecological phenomena, yet very little data are available on how environmental filtering processes influence the composition and traits of butterfly assemblages at high altitudes. We have studied the diversity patterns of butterfly species at 34 sites along an altitudinal gradient ranging from 600 to 2,000 m a.s.l. in the National Park Berchtesgaden (Germany) and analysed traits of butterfly assemblages associated with dispersal capacity, reproductive strategies and developmental time from lowlands to highlands, including phylogenetic analyses. We found a linear decline in butterfly species richness along the altitudinal gradient, but the phylogenetic relatedness of the butterfly assemblages did not increase with altitude. Compared to butterfly assemblages at lower altitudes, those at higher altitudes were composed of species with larger wings (on average 9%) which laid an average of 68% more eggs. In contrast, egg maturation time in butterfly assemblages decreased by about 22% along the altitudinal gradient. Further, butterfly assemblages at higher altitudes were increasingly dominated by less widespread species. Based on our abundance data, but not on data in the literature, population density increased with altitude, suggesting a reversed density-distribution relationship, with higher population densities of habitat specialists in harsh environments. In conclusion, our data provide evidence for significant shifts in the composition of butterfly assemblages and for the dominance of different traits along the altitudinal gradient. In our study, these changes were mainly driven by environmental factors, whereas phylogenetic filtering played a minor role along the studied altitudinal range.

  17. [Effects of irrigation mode and N application rate on cotton field fertilizer N use efficiency and N losses].

    Science.gov (United States)

    Wang, Xiao-Juan; Wei, Chang-Zhou; Zhang, Jun; Dong, Peng; Wang, Juan; Zhu, Qi-Chao; Wang, Jin-Xin

    2012-10-01

    A field experiment was conducted to study the effects of different irrigation modes (drip irrigation and furrow irrigation) and different N application rates (0, 240, 360 and 480 kg N x hm(-2)) on the fertilizer N use efficiency and N losses in a cotton field in Xinjiang, Northwest China. The main N cycling pathways, such as the N uptake by cotton plant, NO3(-)-N residual in soil, NH3 volatilization, NO3(-)-N leaching, and nitrification-denitrification, were quantitatively monitored. Compared with furrow irrigation, drip irrigation increased the seed cotton yield, plant N uptake, and fertilizer N use efficiency significantly. The NO3(-)-N residual in soil was significantly greater under furrow irrigation than under drip irrigation. With the application of fertilizer N, the N loss from NH3 volatilization under drip irrigation occupied 0.06% -0.14% of applied N, and was significantly greater than that under furrow irrigation. The N loss from NO3(-)-N leaching under drip irrigation and furrow irrigation was 4.4% and 8.8% of the applied N, respectively. Compared with furrow irrigation, drip irrigation could significantly decrease the NO3(-)-N leakage rate in leakage water. The nitrification-dinetrification loss under drip irrigation and furrow irrigation was 17.9% and 16.8% of the applied N, respectively. It was suggested that NO3(-)-N leaching and nitrification-denitrification were the main N losses in the cotton fields of Xinjiang.

  18. Adaptation and diversity along an altitudinal gradient in Ethiopian barley (Hordeum vulgare L. landraces revealed by molecular analysis

    Directory of Open Access Journals (Sweden)

    Bitocchi Elena

    2010-06-01

    Full Text Available Abstract Background Among the cereal crops, barley is the species with the greatest adaptability to a wide range of environments. To determine the level and structure of genetic diversity in barley (Hordeum vulgare L. landraces from the central highlands of Ethiopia, we have examined the molecular variation at seven nuclear microsatellite loci. Results A total of 106 landrace populations were sampled in the two growing seasons (Meher and Belg; the long and short rainy seasons, respectively, across three districts (Ankober, Mojanawadera and Tarmaber, and within each district along an altitudinal gradient (from 1,798 to 3,324 m a.s.l. Overall, although significant, the divergence (e.g. FST is very low between seasons and geographical districts, while it is high between different classes of altitude. Selection for adaptation to different altitudes appears to be the main factor that has determined the observed clinal variation, along with population-size effects. Conclusions Our data show that barley landraces from Ethiopia are constituted by highly variable local populations (farmer's fields that have large within-population diversity. These landraces are also shown to be locally adapted, with the major driving force that has shaped their population structure being consistent with selection for adaptation along an altitudinal gradient. Overall, our study highlights the potential of such landraces as a source of useful alleles. Furthermore, these landraces also represent an ideal system to study the processes of adaptation and for the identification of genes and genomic regions that have adaptive roles in crop species.

  19. Ammonia Volatilization and Denitrification Losses from an Irrigated Maize-Wheat Rotation Field in the North China Plain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-Ming; CHEN De-Li; ZHANG Jia-Bao; R. EDIS; HU Chun-Sheng; ZHU An-Ning

    2004-01-01

    Ammonia (NH3) volatilization, denitrification loss, and nitrous oxide (N2O) emission were investigated from an irrigated wheat-maize rotation field on the North China Plain, and the magnitude of gaseous N loss from denitrification and NH3 volatilization was assessed. The micrometeorological gradient diffusion method in conjunction with a Bowen Ratio system was utilized to measure actual NH3 fluxes over a large area, while the acetylene inhibition technique (intact soil cores) was employed for measurement of denitrification losses and N2O emissions. Ammonia volatilization loss was 26.62% of the applied fertilizer nitrogen (N) under maize, while 0.90% and 15.55% were lost from the wheat field at sowing and topdressing, respectively. The differences in NH3 volatilization between different measurement events may be due to differences between the fertilization methods, and to differences in climatic conditions such as soil temperature.Denitrification losses in the fertilized plots were 0.67%-2.87% and 0.31%-0.49% of the applied fertilizer N under maize and wheat after subtracting those of the controls, respectively. Nitrous oxide emissions in the fertilized plots were approximately 0.08%-0.41% and 0.26%-0.34% of the applied fertilizer N over the maize and wheat seasons after subtracting those of the controls, correspondingly. The fertilizer N losses due to NH3 volatilization were markedly higher than those through denitrification and nitrous oxide emissions. These results indicated that NH3 volatilization was an important N transformation in the crop-soil system and was likely to be the major cause of low efficiencies with N fertilizer in the study area. Denitrification was not a very important pathway of N fertilizer loss, but did result in important evolution of the greenhouse gas N2O and the effect of N2O emitted from agricultural fields on environment should not be overlooked.

  20. The dependence of stellar mass and angular momentum losses on latitude and on active region and dipolar magnetic fields

    CERN Document Server

    Garraffo, Cecilia; Cohen, Ofer

    2015-01-01

    Rotation evolution of late-type stars is dominated by magnetic braking and the underlying factors that control this angular momentum loss are important for the study of stellar spin-down. In this work, we study angular momentum loss as a function of two different aspects of magnetic activity using a calibrated Alfv\\'en wave-driven magnetohydrodynamic wind model: the strengths of magnetic spots and their distribution in latitude. By driving the model using solar and modified solar surface magnetograms, we show that the topology of the field arising from the net interaction of both small-scale and large-scale field is important for spin-down rates and that angular momentum loss is not a simple function of large scale magnetic field strength. We find that changing the latitude of magnetic spots can modify mass and angular momentum loss rates by a factor of two. The general effect that causes these differences is the closing down of large-scale open field at mid- and high-latitudes by the addition of the small-sc...

  1. Incidence of Glaucomatous Visual Field Loss : A Ten-Year Follow-up from the Rotterdam Study

    NARCIS (Netherlands)

    Czudowska, Monika A.; Ramdas, Wishal D.; Wolfs, Roger C. W.; Hofman, Albert; De Jong, Paulus T. V. M.; Vingerling, Johannes R.; Jansonius, Nomdo M.

    2010-01-01

    Purpose: To determine the 10-year incidence of glaucomatous visual field loss (GVFL) and to investigate the influence of risk factors for open-angle glaucoma on this incidence. Design: Population-based cohort study. Participants: Participants aged >55 years from the Rotterdam Study. Methods: Of the

  2. Incidence of Glaucomatous Visual Field Loss: A Ten-Year Follow-up from the Rotterdam Study

    NARCIS (Netherlands)

    M.A. Czudowska; W.D. Ramdas; R.C.W. Wolfs; A. Hofman; P.T.V.M. de Jong; J.R. Vingerling; N.M. Jansonius

    2010-01-01

    Purpose: To determine the 10-year incidence of glaucomatous visual field loss (GVFL) and to investigate the influence of risk factors for open-angle glaucoma on this incidence. Design: Population-based cohort study. Participants: Participants aged >55 years from the Rotterdam Study. Methods: Of the

  3. A phytosociological study of the paramo along two altitudinal transects in El Carchi province, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    We here present a plant composition study of paramo grasslands in the East Andean Cordillera of northern Ecuador that discerns altitudinal distribution patterns. This study took place at two locations: the relatively undisturbed Guandera Biological Reserve site and the highly disturbed El Angel Ecol

  4. Ullmann coupling mediated assembly of an electrically driven altitudinal molecular rotor.

    Science.gov (United States)

    Murphy, Colin J; Smith, Zachary C; Pronschinski, Alex; Lewis, Emily A; Liriano, Melissa L; Wong, Chloe; Ivimey, Christopher J; Duffy, Mitchell; Musial, Wojciech; Therrien, Andrew J; Thomas, Samuel W; Sykes, E Charles H

    2015-12-21

    Surface-bound molecular rotation can occur with the rotational axis either perpendicular (azimuthal) or parallel (altitudinal) to the surface. The majority of molecular rotor studies involve azimuthal rotors, whereas very few altitudinal rotors have been reported. In this work, altitudinal rotors are formed by means of coupling aryl halides through a surface-mediated Ullmann coupling reaction, producing a reaction state-dependent altitudinal molecular rotor/stator. All steps in the reaction on a Cu(111) surface are visualized by low-temperature scanning tunneling microscopy. The intermediate stage of the coupling reaction is a metal-organic complex consisting of two aryl groups attached to a single copper atom with the aryl rings angled away from the surface. This conformation leads to nearly unhindered rotational motion of ethyl groups at the para positions of the aryl rings. Rotational events of the ethyl group are both induced and quantified by electron tunneling current versus time measurements and are only observed for the intermediate structure of the Ullmann coupling reaction, not the starting material or finished product in which the ethyl groups are static. We perform an extensive set of inelastic electron tunneling driven rotation experiments that reveal that torsional motion around the ethyl group is stimulated by tunneling electrons in a one-electron process with an excitation energy threshold of 45 meV. This chemically tunable system offers an ideal platform for examining many fundamental aspects of the dynamics of chemically tunable molecular rotor and motors. PMID:26567846

  5. Altitudinal distribution of birds in a mountainous region in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Francisco Mallet-Rodrigues

    2010-08-01

    Full Text Available We studied the altitudinal distribution of 426 bird species in the Serra dos Órgãos, a mountainous region in southeastern Brazil. Thirty-four localities were visited between 1991 and 2009. Our study revealed a decline in bird species richness with elevation, although a smaller number of species was recorded at lower altitudes (below 300 m possibly due to local extinctions caused by the intense human occupation of the region. A less diverse avifauna was found above 2,000 m, with only one species (Caprimulgus longirostris recorded exclusively in this altitudinal range. Most endemic species were found between 300 and 1,200 m, but the endemism was more significant at higher altitudes. Nearly half of the birds found above 1,400 m were endemic species. Most of the threatened species from the state of Rio de Janeiro recorded in our study were found below 1,200 m, but no significant difference was found between the proportions of threatened species among different altitudinal ranges. Species of seventeen genera have exhibited some replacement (sometimes with partial overlap along altitudinal gradients.

  6. Prospective large-scale field study generates predictive model identifying major contributors to colony losses.

    Science.gov (United States)

    Kielmanowicz, Merav Gleit; Inberg, Alex; Lerner, Inbar Maayan; Golani, Yael; Brown, Nicholas; Turner, Catherine Louise; Hayes, Gerald J R; Ballam, Joan M

    2015-04-01

    Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA. Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses. Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA. In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides. Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration. Our results show that a linear association between load of viruses (DWV or IAPV) in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees). The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses. This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss. The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health. PMID:25875764

  7. A field study of triclosan loss rates in river water (Cibolo Creek, TX).

    Science.gov (United States)

    Morrall, Donna; McAvoy, Drew; Schatowitz, Bert; Inauen, Josef; Jacob, Martin; Hauk, Armin; Eckhoff, William

    2004-02-01

    Triclosan (TCS) is an anti-microbial agent used in down-the-drain consumer products. Following sewage treatment some of the triclosan will enter receiving waters. This study was designed to determine the die-away rate of triclosan released into a river as part of the sewage treatment plant effluent matrix. The study was conducted in Cibolo Creek, a moderate sized stream (discharge approximately 0.1 m(3)s(-1)) located in South Central Texas. Triclosan was analyzed from samples collected upstream of the sewage treatment plant, the sewage treatment plant effluent, and the river downstream from the effluent discharge. The first-order loss rate of parent triclosan from the water column was calculated from measured data (0.06 h(-1)) and this rate corresponded to a 76% reduction in triclosan over an 8 km river reach below the discharge. Mathematical modeling indicated that sorption and settling accounted for approximately 19% of total triclosan loss over 8 km. When removing sorption and settling, the remaining amount of triclosan had an estimated first-order loss rate of 0.25 h(-1). This loss rate was presumably due to other processes such as biodegradation and photolysis. These data show that loss of parent triclosan from the water column is rapid. Additional data are needed to fully document loss mechanisms. PMID:14599511

  8. Prospective large-scale field study generates predictive model identifying major contributors to colony losses.

    Directory of Open Access Journals (Sweden)

    Merav Gleit Kielmanowicz

    2015-04-01

    Full Text Available Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA. Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses. Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA. In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides. Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration. Our results show that a linear association between load of viruses (DWV or IAPV in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees. The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses. This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss. The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health.

  9. Prospective large-scale field study generates predictive model identifying major contributors to colony losses.

    Science.gov (United States)

    Kielmanowicz, Merav Gleit; Inberg, Alex; Lerner, Inbar Maayan; Golani, Yael; Brown, Nicholas; Turner, Catherine Louise; Hayes, Gerald J R; Ballam, Joan M

    2015-04-01

    Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA. Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses. Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA. In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides. Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration. Our results show that a linear association between load of viruses (DWV or IAPV) in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees). The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses. This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss. The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health.

  10. Visual field loss in schizophrenia: evaluation of magnocellular pathway dysfunction in schizophrenic patients and their parents

    Directory of Open Access Journals (Sweden)

    Gracitelli CPB

    2013-05-01

    Full Text Available Carolina Pelegrini Barbosa Gracitelli,1 Fabiana Benites Vaz de Lima,2,3 Rodrigo A Bressan,2,3 Augusto Paranhos Junior1 1Department of Ophthalmology, Federal University of São Paulo (UNIFESP, São Paulo, SP, Brazil; 2LiNC – Interdisciplinary Laboratory of Neuroimaging and Cognition, Department of Psychiatry, Federal University of São Paulo (UNIFESP, São Paulo, SP, Brazil; 3PROESQ – Schizophrenia Program, Federal University of São Paulo (UNIFESP, São Paulo, SP, Brazil Purpose: We sought to evaluate the visual pathway deficits in schizophrenic patients, compared with their parents and healthy controls, using Matrix frequency doubling technology (FDT perimetry. Matrix FDT is an ophthalmic test used to detect visual field loss. Method: A total of 13 patients, 13 parents, and 12 healthy controls were enrolled in the study. Participants were subjected to Matrix FDT perimetry in a single test session. We analyzed the mean deviation for each eye and used a generalized estimated equation to evaluate differences among the groups and correct the dependency between the eyes. Results: The global mean deviation (presented as the mean of both eyes was significantly lower in the schizophrenic patients than in their parents or controls. Analysis of the general sensitivity of the fibers crossing the optic chiasm showed a difference between the groups (P = 0.006, indicating that the sensitivity of the fibers crossing the optic chiasm was lower than those which did not cross. But when we analyzed the specific groups, the difference between the fibers was not considerable. Comparison of the right and left hemispheres showed that general sensitivity was lower for the left hemisphere, but when we analyzed specific groups, the difference was not significant (P = 0.29. Conclusion: These findings are suggestive of a lower global sensitivity in schizophrenic patients and their parents compared with controls. This difference may be an endophenotype of schizophrenia

  11. Flow field and pressure loss analysis of junction and its structure optimization of aircraft hydraulic pipe system

    Institute of Scientific and Technical Information of China (English)

    Li Xin; Wang Shaoping

    2013-01-01

    The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft.In this study,the flow fields of T-junction and Y-junction were analyzed using shear stress transport (SST) model in ANSYS/CFX software.The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences,meanwhile,the eddy and velocity shock existed in the corner of the T-junction,and the limit working state was obtained.Although the eddy disappeared in Y-junction,the velocity shock and pressure loss were still too big.To address these faults,an arc-junction was designed.Based on the flow fields of arc-junction,the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction.Additionally,8 series of arcjunction with different radiuses were tested to get the variation rule of velocity peak.Through the computation of the pressure loss of three junctions,the arc-junction had a lowest loss value,and its pressure loss reached the minimum value when the curvature radius is 35.42 mm,meanwhile,the velocity shock has decreased in a low phase.

  12. Computation of self-field hysteresis losses in conductors with helicoidal structure using a 2D finite element method

    Science.gov (United States)

    Stenvall, A.; Siahrang, M.; Grilli, F.; Sirois, F.

    2013-04-01

    It is well known that twisting current-carrying conductors helps to reduce their coupling losses. However, the impact of twisting on self-field hysteresis losses has not been as extensively investigated as that on the reduction of coupling losses. This is mostly because the reduction of coupling losses has been an important issue to tackle in the past, and it is not possible to consider twisting within the classical two-dimensional (2D) approaches for the computation of self-field hysteresis losses. Recently, numerical codes considering the effect of twisting in continuous symmetries have appeared. For general three-dimensional (3D) simulations, one issue is that no robust, widely accepted and easy to obtain model for expressing the relationship between the current density and the electric field is available. On the other hand, we can consider that in these helicoidal structures currents flow only along the helicoidal trajectories. This approach allows one to use the scalar power-law for superconductor resistivity and makes the eddy current approach to a solution of a hysteresis loss problem feasible. In this paper we use the finite element method to solve the eddy current model in helicoidal structures in 2D domains utilizing the helicoidal symmetry. The developed tool uses the full 3D geometry but allows discretization which takes advantage of the helicoidal symmetry to reduce the computational domain to a 2D one. We utilize in this tool the non-linear power law for modelling the resistivity in the superconducting regions and study how the self-field losses are influenced by the twisting of a 10-filament wire. Additionally, in the case of high aspect ratio tapes, we compare the results computed with the new tool and a one-dimensional program based on the integral equation method and developed for simulating single layer power cables made of ReBCO coated conductors. Finally, we discuss modelling issues and present open questions related to helicoidal structures

  13. Computer Calculations of Eddy-Current Power Loss in Rotating Titanium Wheels and Rims in Localized Axial Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Mayhall, D J; Stein, W; Gronberg, J B

    2006-05-15

    We have performed preliminary computer-based, transient, magnetostatic calculations of the eddy-current power loss in rotating titanium-alloy and aluminum wheels and wheel rims in the predominantly axially-directed, steady magnetic fields of two small, solenoidal coils. These calculations have been undertaken to assess the eddy-current power loss in various possible International Linear Collider (ILC) positron target wheels. They have also been done to validate the simulation code module against known results published in the literature. The commercially available software package used in these calculations is the Maxwell 3D, Version 10, Transient Module from the Ansoft Corporation.

  14. [Altitudinal richness patterns of Papilionidae, Pieridae and Nymphalidae (Lepidoptera) in Mexican mountain areas].

    Science.gov (United States)

    Monteagudo Sabaté, David; Luis Martínez, Moisés Armando

    2013-09-01

    Altitudinal richness patterns of Papilionidae, Pieridae and Nymphalidae (Lepidoptera) in Mexican mountain areas. Butterflies constitute an useful group to investigate biodiversity patterns in specific geographic areas. The aim of this study was to describe the altitudinal patterns distribution and to recognize the main grouping factors of these families. We conducted a comparative study between the butterfly fauna (Papilionidae, Pieridae and Nymphalidae) of five Mexican mountain ranges (Sierra de Manantlán, Sierra de Atoyac de Alvarez, Loxicha Region, Teocelo-Xalapa and Sierra de Juárez), that included 34 sites of altitudinal ranges from 100 to 2 820m. Data was obtained from the Zoology Museum of the National University of Mexico, and comprised more than 60 000 butterfly records of 398 taxa (subspecies level) proceeding during the last 35 years. Fauna similarity between localities were analyzed using a cluster analysis by Sorensen similarity coefficient. Species richness showed a general tendency to decrease with altitude; the main difference was found between the locality with higher altitude and the rest of the sites. The principal factors affecting the identified clusters followed this order: the location in Pacific or Atlantic slope, and location on a particular mountain range. Three altitudinal levels (low elevations, up to 1 200m; intermediate elevations, from 1200 to 1800 m; and high elevations, from 1800 to 2500 m) were described in accordance to their main characteristic taxa. While Neartic elements were common in the highest altitudinal floor, Neotropical taxa were common in the lowest one. It was more difficult to characterize the intermediate level in which a high number of localities were clustered; this intermediate level was characterized by the presence of some endemic species. The results suggest that historical factors are preeminent in butterfly fauna composition in these areas. Future studies may include other Mexican mountain areas to obtain

  15. Body Size Adaptations to Altitudinal Climatic Variation in Neotropical Grasshoppers of the Genus Sphenarium (Orthoptera: Pyrgomorphidae.

    Directory of Open Access Journals (Sweden)

    Salomón Sanabria-Urbán

    Full Text Available Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group.

  16. First Measurements of the Unique Influence of Spin on the Energy Loss of Ultrarelativistic Electrons in Strong Electromagnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Kirsebom, K.; Mikkelsen, U.; Uggerhoj, E.; Elsener, K.; Ballestrero, S.; Sona, P.; Vilakazi, Z. Z.

    2001-07-30

    Although some authors have claimed that the effect is not detectable, we show experimentally for the first time that as the quantum parameter {chi} grows beyond 1, an increasingly large part of the hard radiation emitted arises from the spin of the electron. Results for the energy loss of electrons in the energy range 35--243GeV incident on a W single crystal are presented. Close to the axial direction the strong electromagnetic fields induce a radiative energy loss which is significantly enhanced compared to incidence on an amorphous target. In such continuously strong fields, the radiation process is highly nonperturbative for ultrarelativistic particles and a full quantum description is needed. The remarkable effect of spin flips and the energy loss is connected to the presence of a field comparable in magnitude to the Schwinger critical field, E{sub 0}=m{sup 2}c{sup 3}/e{Dirac_h} , in the rest frame of the emitting electron.

  17. Development towards a fast ion loss detector for the reversed field pinch

    Science.gov (United States)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.; Egedal, J.

    2016-11-01

    A fast ion loss detector has been constructed and implemented on the Madison Symmetric Torus (MST) to investigate energetic ion losses and transport due to energetic particle and MHD instabilities. The detector discriminates particle orbits solely on pitch and consists of two thin-foil, particle collecting plates that are symmetric with respect to the device aperture. One plate collects fast ion signal, while the second aids in the minimization of background and noise effects. Initial measurements are reported along with suggestions for the next design phase of the detector.

  18. Seasonal pattern of apoplastic solute accumulation and loss of cell turgor during ripening of Vitis vinifera fruit under field conditions

    OpenAIRE

    Wada, Hiroshi; MATTHEWS, MARK A.; Shackel, Ken A

    2009-01-01

    Using a novel pressure membrane (PM) apparatus for the extraction of apoplastic fluid from field-grown grape (Vitis vinifera L.) berries, our hypothesis that significant apoplast solutes accumulate at the beginning of the ripening process (i.e. veraison), and that this accumulation might contribute to progressive berry softening due to a progressive loss of mesocarp cell turgor pressure (P) was tested. It was necessary to correct the solute potential (Ψs) of fluid collected with the PM for di...

  19. Linking water balance of mountain grasslands along altitudinal transects to climate and land-use change

    Science.gov (United States)

    Leitinger, Georg; Obojes, Nikolaus; Tasser, Erich; Tappeiner, Ulrike

    2010-05-01

    Changes of the water balance of mountain grasslands with regard to climate and land-use changes are a popular research field since years. Measuring evapotranspiration (EVT) for different land-use types and plant communities at varying sea level helps us to understand the change of water availability in a future environment. Linked with transplantation experiments, this method is promising to cover most forecasted scenarios. Although the mentioned approach is well established, our study is innovative in so far as the field work as well as data analyses was supported by more than 50 pupils from a secondary school for agriculture and food industry. Hence, a huge number of field measurements could be conducted at the same time distributed over a whole alpine valley. In our study site Stubai Valley (300km²), Tyrol, Austria, 13 sites on 4 different altitudinal transects (valley bottom, hillside, and sub-alpine/alpine) ranging from 900m a.s.l. up to 2400m a.s.l. were selected and equipped with weather stations recording air temperature, air humidity, precipitation, solar radiation, and soil water content in different soil depths at 15-minute interval. Additionally, more than 300 small lysimeters have been installed and data on EVT, infiltration, leaf conductivity, and soil wetness was collected on 7 measuring days. The measurements spanned an entire daylight period from sunrise to sunset. Moreover, soil and vegetation analyses on all selected plots complete the enormous data pool. The lysimeters on each plot contained samples of long-stemmed local vegetation (1 cut / 1 uncut), short-stemmed local vegetation (1 cut / 1 uncut), alpine standard vegetation (1), intensive standard vegetation (1 cut / 1 uncut), and water for potential transpiration (1). Each type was replicated three times resulting in a total number of 24 lysimeters per study plot. Results revealed a little increase in EVT rates for the Alpine Standard Vegetation transplanted to lower altitudes and slight

  20. A DYNAMIC MIXED MODEL WITH NITROGEN LEACHING LOSSES FROM THE PONDED PADDY RICE FIELD UNDER SITUATION OF BURIED PIPE DRAINAGE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to study the law of nitrogen leaching losses from the paddy field under the condition of drainage, based on the theories of potential energy and solute transport, a water-nitrogen dynamic mixed model by combining the flow net with dynamic method was established. In the computation of buried pipe drainage, the superposition principle was used to simplify the complex solving of the two-dimensional problem about water-nitrogen transportation in Soil-Plant-Air-Continuous (SPAC) system into several one-dimensional problems. The presented method is simple and practical. Some field experiments were carried out to demonstrate the validity of the model.

  1. Dataset of MIGRAME Project (Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains)

    OpenAIRE

    Pérez-Luque, Antonio Jesús; Zamora, Regino; Bonet, Francisco Javier; Pérez-Pérez, Ramón

    2015-01-01

    Abstract In this data paper, we describe the dataset of the Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains (MIGRAME) project, which aims to assess the capacity of altitudinal migration and colonization of marginal habitats by Quercus pyrenaica Willd. forests in Sierra Nevada (southern Spain) considering two global-change drivers: temperature increase and land-use changes. The dataset includes information of the forest structure (diamete...

  2. Dataset of MIGRAME Project (Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains)

    OpenAIRE

    Pérez-Luque, Antonio Jesús; Zamora, Regino; Bonet, Francisco Javier; Pérez-Pérez, Ramón

    2015-01-01

    In this data paper, we describe the dataset of the Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains (MIGRAME) project, which aims to assess the capacity of altitudinal migration and colonization of marginal habitats by Quercus pyrenaica Willd. forests in Sierra Nevada (southern Spain) considering two global-change drivers: temperature increase and land-use changes. The dataset includes information of the forest structure (diameter size, t...

  3. Damping loss factor estimation of two-dimensional orthotropic structures from a displacement field measurement

    Science.gov (United States)

    Cherif, Raef; Chazot, Jean-Daniel; Atalla, Noureddine

    2015-11-01

    This paper presents a damping loss factor estimation method of two-dimensional orthotropic structures. The method is based on a scanning laser vibrometer measurement. The dispersion curves of the studied structures are first estimated at several chosen angles of propagation with a spatial Fourier transform. Next the global damping loss factor is evaluated with the proposed inverse wave method. The method is first tested using numerical results obtained from a finite element model. The accuracy of the proposed method is then experimentally investigated on an isotropic aluminium panel and two orthoropic sandwich composite panels with a honeycomb core. The results are finally compared and validated over a large frequency band with classical methods such as the half-power bandwidth method (3 dB method), the decay rate method and the steady-state power input method. The present method offers the possibility of structural characterization with a simple measurement scan.

  4. Loss of the Statical Stabity of Electrical Machine Rotor Under Influence of Stator Magnetic Field

    Directory of Open Access Journals (Sweden)

    Shekyan H.G.

    2007-06-01

    Full Text Available It is assumed, that magnetic forces, acting on to the rotor by the stator field, are varied proportional with displacements. The criteria of rotor statical stability, depending on rigid characteristics and boundary conditions are obtained.

  5. Bryophyte species richness and composition along an altitudinal gradient in Gongga Mountain, China.

    Directory of Open Access Journals (Sweden)

    Shou-Qin Sun

    Full Text Available An investigation of terrestrial bryophyte species diversity and community structure along an altitudinal gradient from 2,001 to 4,221 m a.s.l. in Gongga Mountain in Sichuan, China was carried out in June 2010. Factors which might affect bryophyte species composition and diversity, including climate, elevation, slope, depth of litter, vegetation type, soil pH and soil Eh, were examined to understand the altitudinal feature of bryophyte distribution. A total of 14 representative elevations were chosen along an altitudinal gradient, with study sites at each elevation chosen according to habitat type (forests, grasslands and accessibility. At each elevation, three 100 m × 2 m transects that are 50 m apart were set along the contour line, and three 50 cm × 50 cm quadrats were set along each transect at an interval of 30 m. Species diversity, cover, biomass, and thickness of terrestrial bryophytes were examined. A total of 165 species, including 42 liverworts and 123 mosses, are recorded in Gongga mountain. Ground bryophyte species richness does not show any clear elevation trend. The terrestrial bryophyte cover increases with elevation. The terrestrial bryophyte biomass and thickness display a clear humped relationship with the elevation, with the maximum around 3,758 m. At this altitude, biomass is 700.3 g m(-2 and the maximum thickness is 8 cm. Bryophyte distribution is primarily associated with the depth of litter, the air temperature and the precipitation. Further studies are necessary to include other epiphytes types and vascular vegetation in a larger altitudinal range.

  6. Altitudinal Clinal Variation in Wing Size & Shape in African Drosophila melanogaster: One Cline or Many?

    OpenAIRE

    Pitchers, William; Pool, John E.; Dworkin, Ian

    2012-01-01

    Geographical patterns of morphological variation have been useful in addressing hypotheses about environmental adaptation. In particular, latitudinal clines in phenotypes have been studied in a number of Drosophila species. Some environmental conditions along latitudinal clines – e.g. temperature – also vary along altitudinal clines, but these have been studied infrequently and it remains unclear whether these environmental factors are similar enough for convergence or parallel evolution. Mos...

  7. Altitudinal Patterns of Species Diversity and Phylogenetic Diversity across Temperate Mountain Forests of Northern China

    Science.gov (United States)

    Zhang, Wenxin; Huang, Dizhou; Wang, Renqing; Liu, Jian; Du, Ning

    2016-01-01

    The spatial patterns of biodiversity and their underlying mechanisms have been an active area of research for a long time. In this study, a total of 63 samples (20m × 30m) were systematically established along elevation gradients on Mount Tai and Mount Lao, China. We explored altitudinal patterns of plant diversity in the two mountain systems. In order to understand the mechanisms driving current diversity patterns, we used phylogenetic approaches to detect the spatial patterns of phylogenetic diversity and phylogenetic structure along two elevation gradients. We found that total species richness had a monotonically decreasing pattern and tree richness had a unimodal pattern along the elevation gradients in the two study areas. However, altitudinal patterns in shrub richness and herbs richness were not consistent on the two mountains. At low elevation, anthropogenic disturbances contributed to the increase of plant diversity, especially for shrubs and herbs in understory layers, which are more sensitive to changes in microenvironment. The phylogenetic structure of plant communities exhibited an inverted hump-shaped pattern along the elevation gradient on Mount Tai, which demonstrates that environmental filtering is the main driver of plant community assembly at high and low elevations and inter-specific competition may be the main driver of plant community assembly in the middle elevations. However, the phylogenetic structure of plant communities did not display a clear pattern on Mount Lao where the climate is milder. Phylogenetic beta diversity and species beta diversity consistently increased with increasing altitudinal divergence in the two study areas. However, the altitudinal patterns of species richness did not completely mirror phylogenetic diversity patterns. Conservation areas should be selected taking into consideration the preservation of high species richness, while maximizing phylogenetic diversity to improve the potential for diversification in the

  8. Altitudinal Patterns of Species Diversity and Phylogenetic Diversity across Temperate Mountain Forests of Northern China.

    Science.gov (United States)

    Zhang, Wenxin; Huang, Dizhou; Wang, Renqing; Liu, Jian; Du, Ning

    2016-01-01

    The spatial patterns of biodiversity and their underlying mechanisms have been an active area of research for a long time. In this study, a total of 63 samples (20m × 30m) were systematically established along elevation gradients on Mount Tai and Mount Lao, China. We explored altitudinal patterns of plant diversity in the two mountain systems. In order to understand the mechanisms driving current diversity patterns, we used phylogenetic approaches to detect the spatial patterns of phylogenetic diversity and phylogenetic structure along two elevation gradients. We found that total species richness had a monotonically decreasing pattern and tree richness had a unimodal pattern along the elevation gradients in the two study areas. However, altitudinal patterns in shrub richness and herbs richness were not consistent on the two mountains. At low elevation, anthropogenic disturbances contributed to the increase of plant diversity, especially for shrubs and herbs in understory layers, which are more sensitive to changes in microenvironment. The phylogenetic structure of plant communities exhibited an inverted hump-shaped pattern along the elevation gradient on Mount Tai, which demonstrates that environmental filtering is the main driver of plant community assembly at high and low elevations and inter-specific competition may be the main driver of plant community assembly in the middle elevations. However, the phylogenetic structure of plant communities did not display a clear pattern on Mount Lao where the climate is milder. Phylogenetic beta diversity and species beta diversity consistently increased with increasing altitudinal divergence in the two study areas. However, the altitudinal patterns of species richness did not completely mirror phylogenetic diversity patterns. Conservation areas should be selected taking into consideration the preservation of high species richness, while maximizing phylogenetic diversity to improve the potential for diversification in the

  9. Distribution of vascular plants along the altitudinal gradient of Gyebangsan (Mt.) in Korea

    OpenAIRE

    Jong-Cheol Yang; Hee-Suk Hwang; Hye-Jeong Lee 167; Su-Young Jung; Seong-Jin Ji; Seung-Hwan Oh; You-Mi Lee

    2014-01-01

    This study was conducted to examine the distribution of vascular plants along the altitudinal gradient and investigation routes of Gyebangsan (Mt.) in Korea. The total number of flora of Gyebangsan (Mt.) was 510 taxa in total, comprising 83 families, 283 genera, 449 species, four subspecies, 52 varieties and five forms. In the flora of this area, 14 taxa were Korean endemic plants and 17 taxa were rare plants. Naturalized plants in Korea numbered 27 taxa. The number of vascular plants monoton...

  10. Soil respiration along an altitudinal gradient in a subalpine secondary forest in China

    OpenAIRE

    Luo S.; Liu G; Li Z; Hu C; Gong L; Wang M; Hu H

    2015-01-01

    The subalpine forest ecosystems in the Miyaluo Forest District in western Sichuan (China) could be very sensitive to global climate change, with important consequences for the regional carbon (C) balance. In a birch secondary forest in this area, we measured plots with (Control) and without (No Litter) leaf litter to explore variation in soil respiration and its relationship with environmental factors along an altitudinal gradient, and to quantify the litter contribution to soil respiration. ...

  11. Angular momentum loss of primordial gas in Lyman-alpha radiation field

    CERN Document Server

    Yajima, Hidenobu

    2013-01-01

    We present results on the radiation drag exerted by an isotropic and homogenous background of Lya photons on neutral gas clouds orbiting within HII regions around Population III stars of different masses. The Doppler shift causes a frequency difference between photons moving in the direction of the cloud and opposite to it resulting in a net momentum loss of the cloud in the direction of motion. We find that half of the angular momentum of gas with v_theta 10^8 yr even for low velocity clouds. Our results suggest that a sweet spot exists for the loss of angular momentum by radiation drag for gas clouds at z > 10 and with v ~ 20 km/s. Comparison to dynamical friction forces acting on typical gas clouds suggest that radiation drag is the dominant effect impacting the orbit. We propose that this effect can suppress the formation of extended gas discs in the first galaxies and help gas accretion near galactic centres and central black holes.

  12. Importance of mountain height and latitude for the altitudinal distribution limits of vascular plants in Scandinavia: are the mountains high enough?

    OpenAIRE

    Arvid Odland

    2010-01-01

    The main aim of the present paper was to study regional differences in the altitudinal distribution limits of vascular plants in relation to mountain height and latitudinal position. Altitudinal limits from previously studied areas were compared with the altitudinal distribution limits given by Lid and Lid (2005) as a reference. Based on these comparisons, different trend lines were used to evaluate the effects of mountain height and thereby estimate how high a mountain must be for vascular p...

  13. SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF PARTITION WITH MICRO-PERFORATED PLATE INSERTION UNDER DIFFUSE FIELD INCIDENCE

    Directory of Open Access Journals (Sweden)

    A. Putra

    2013-06-01

    Full Text Available In noise control applications, a double-leaf partition has been applied widely as a lightweight structure for noise insulation, such as in car doors, train bodies, and aircraft fuselages. Unfortunately, the insulation performance deteriorates significantly at mass-air-mass resonance due to coupling between the panels and the air in the gap. This paper investigates the effect of a micro-perforated panel (MPP, inserted in the conventional double-panel partition, on sound transmission loss at troublesome resonant frequencies. It is found that the transmission loss improves at this resonance if the MPP is located at a distance of less than half that of the air gap. A mathematical model is derived for the diffuse field incidence of acoustic loading.

  14. Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

    DEFF Research Database (Denmark)

    Magnusson, N.; Abrahamsen, Asger Bech; Liu, Dawei;

    2014-01-01

    MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must...... be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB2 conductors. In this article we reason towards...... equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB2 DC coils in the 1–4T range with low AC magnetic field and current ripples....

  15. Variation and Genetic Structure in Platanus mexicana (Platanaceae along Riparian Altitudinal Gradient

    Directory of Open Access Journals (Sweden)

    Dulce M. Galván-Hernández

    2015-01-01

    Full Text Available Platanus mexicana is a dominant arboreal species of riparian ecosystems. These ecosystems are associated with altitudinal gradients that can generate genetic differences in the species, especially in the extremes of the distribution. However, studies on the altitudinal effect on genetic variation to riparian species are scarce. In Mexico, the population of P. mexicana along the Colipa River (Veracruz State grows below its reported minimum altitude range, possibly the lowest where this tree grows. This suggests that altitude might be an important factor in population genetics differentiation. We examined the genetic variation and population structuring at four sites with different altitudes (70, 200, 600 and 1700 m a.s.l. using ten inter-simple sequence repeats (ISSR markers. The highest value for Shannon index and Nei’s gene diversity was obtained at 1700 m a.s.l. (He = 0.27, Ne = 1.47, I = 0.42 and polymorphism reached the top value at the middle altitude (% p = 88.57. Analysis of molecular variance (AMOVA and STRUCTURE analysis indicated intrapopulation genetic differentiation. The arithmetic average (UPGMA dendrogram identified 70 m a.s.l. as the most genetically distant site. The genetic structuring resulted from limited gene flow and genetic drift. This is the first report of genetic variation in populations of P. mexicana in Mexico. This research highlights its importance as a dominant species, and its ecological and evolutionary implications in altitudinal gradients of riparian ecosystems.

  16. Plant Species Diversity along an Altitudinal Gradient of Bhabha Valley in Western Himalaya

    Institute of Scientific and Technical Information of China (English)

    Amit Chawla; S. Rajkumar; K.N. Singh; Brij Lal; R.D. Singh; A. K. Thukral

    2008-01-01

    The present study highlights the rich species diversity of higher plants in the Bhabha Valley of western Himalaya in India. The analysis of species diversity revealed that a total of 313 species of higher plants inhabit the valley with a charactersfic of moist alpine shrub vegetation. The herbaceous life forms dominate and increase with increasing altitude. The major representations are from the families Asteraceae, Rosaceae, Lamiaceae and Poaceae, suggesting thereby the alpine meadow nature of the study area. The effect of altitude on species diversity displays a hump-shaped curve which may be attributed to increase in habitat diversity at the median ranges and relatively less habitat diversity at higher altitudes. The anthropogenic pressure at lower altitudes results in low plant diversity towards the bottom of the valley with most of the species being exotic in nature. Though the plant diversity is less at higher altitudinal ranges, the uniqueness is relatively high with high species replacement rates. More than 90% of variability in the species diversity could be explained using appropriate quantitative and statistical analysis along the altitudinal gradient. The valley harbours 18 threatened and 41 endemic species, most of which occur at higher altitudinal gradients due to habitat specificity.

  17. Selection by pollinators on floral traits in generalized Trollius ranunculoides (Ranunculaceae along altitudinal gradients.

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Zhao

    Full Text Available Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral differentiation. We investigated the variation of Trollius ranunculoides flowers and its pollinators along an altitudinal gradient on the eastern Qinghai-Tibet Plateau, and measured phenotypic selection by pollinators on floral traits across populations. The results showed significant decline of visitation rate of bees along altitudinal gradients, while flies was unchanged. When fitness is estimated by the visitation rate rather than the seed number per plant, phenotypic selection on the sepal length and width shows a significant correlation between the selection strength and the altitude, with stronger selection at higher altitudes. However, significant decreases in the sepal length and width of T. ranunculoides along the altitudinal gradient did not correspond to stronger selection of pollinators. In contrast to the pollinator visitation, mean annual precipitation negatively affected the sepal length and width, and contributed more to geographical variation in measured floral traits than the visitation rate of pollinators. Therefore, the sepal size may have been influenced by conflicting selection pressures from biotic and abiotic selective agents. This study supports the hypothesis that lower pollinator availability at high altitude can intensify selection on flower attractive traits, but abiotic selection is preventing a response to selection from pollinators.

  18. Changes in pollinator fauna affect altitudinal variation of floral size in a bumblebee-pollinated herb.

    Science.gov (United States)

    Nagano, Yusuke; Abe, Kota; Kitazawa, Tomoaki; Hattori, Mitsuru; Hirao, Akira S; Itino, Takao

    2014-09-01

    Geographic trait variations are often caused by locally different selection regimes. As a steep environmental cline along altitude strongly influences adaptive traits, mountain ecosystems are ideal for exploring adaptive differentiation over short distances. We investigated altitudinal floral size variation of Campanula punctata var. hondoensis in 12 populations in three mountain regions of central Japan to test whether the altitudinal floral size variation was correlated with the size of the local bumblebee pollinator and to assess whether floral size was selected for by pollinator size. We found apparent geographic variations in pollinator assemblages along altitude, which consequently produced a geographic change in pollinator size. Similarly, we found altitudinal changes in floral size, which proved to be correlated with the local pollinator size, but not with altitude itself. Furthermore, pollen removal from flower styles onto bees (plant's male fitness) was strongly influenced by the size match between flower style length and pollinator mouthpart length. These results strongly suggest that C. punctata floral size is under pollinator-mediated selection and that a geographic mosaic of locally adapted C. punctata exists at fine spatial scale.

  19. Genomewide scan for adaptive differentiation along altitudinal gradient in the Andrew's toad Bufo andrewsi.

    Science.gov (United States)

    Guo, Baocheng; Lu, Di; Liao, Wen Bo; Merilä, Juha

    2016-08-01

    Recent studies of humans, dogs and rodents have started to discover the genetic underpinnings of high altitude adaptations, yet amphibians have received little attention in this respect. To identify possible signatures of adaptation to altitude, we performed a genome scan of 15 557 single nucleotide polymorphisms (SNPs) obtained with restriction site-associated DNA sequencing of pooled samples from 11 populations of Andrew's toad (Bufo andrewsi) from the edge of the Tibetan Plateau, spanning an altitudinal gradient from 1690 to 2768 m.a.s.l. We discovered significant geographic differentiation among all sites, with an average FST   = 0.023 across all SNPs. Apart from clear patterns of isolation by distance, we discovered numerous outlier SNPs showing strong associations with variation in altitude (1394 SNPs), average annual temperature (1859 SNPs) or both (1051 SNPs). Levels and patterns of genetic differentiation in these SNPs were consistent with the hypothesis that they have been subject to directional selection and reflect adaptation to altitudinal variation among the study sites. Genes with footprints of selection were significantly enriched in binding and metabolic processes. Several genes potentially related to high altitude adaptation were identified, although the identity and functional significance of most genomic targets of selection remain unknown. In general, the results provide genomic support for results of earlier common garden and low coverage genetic studies that have uncovered substantial adaptive differentiation along altitudinal and latitudinal gradients in amphibians. PMID:27289071

  20. Altitudinal patterns and controls of plant and soil nutrient concentrations and stoichiometry in subtropical China

    Science.gov (United States)

    He, Xianjin; Hou, Enqing; Liu, Yang; Wen, Dazhi

    2016-04-01

    Altitude is a determining factor of ecosystem properties and processes in mountains. This study investigated the changes in the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and their ratios in four key ecosystem components (forest floor litter, fine roots, soil, and soil microorganisms) along an altitudinal gradient (from 50 m to 950 m a.s.l.) in subtropical China. The results showed that soil organic C and microbial biomass C concentrations increased linearly with increasing altitude. Similar trends were observed for concentrations of total soil N and microbial biomass N. In contrast, the N concentration of litter and fine roots decreased linearly with altitude. With increasing altitude, litter, fine roots, and soil C:N ratios increased linearly, while the C:N ratio of soil microbial biomass did not change significantly. Phosphorus concentration and C:P and N:P ratios of all ecosystem components generally had nonlinear relationships with altitude. Our results indicate that the altitudinal pattern of plant and soil nutrient status differs among ecosystem components and that the relative importance of P vs. N limitation for ecosystem functions and processes shifts along altitudinal gradients.

  1. Intercropping reduces nitrate leaching from under field crops without loss of yield: A modelling study

    NARCIS (Netherlands)

    Whitmore, A.P.; Schröder, J.J.

    2007-01-01

    A model of soil nitrogen dynamics under competing intercrops is described and used to interpret two sets of experimental field data from the literature. In one series of experiments, maize received slurry and mineral nitrogen (N) fertiliser or mineral N alone and was grown either alone or intercropp

  2. Experimental evidence of edge intrinsic momentum source driven by kinetic ion loss and edge radial electric fields in tokamaks

    Science.gov (United States)

    Boedo, J. A.; deGrassie, J. S.; Grierson, B.; Stoltzfus-Dueck, T.; Battaglia, D. J.; Rudakov, D. L.; Belli, E. A.; Groebner, R. J.; Hollmann, E.; Lasnier, C.; Solomon, W. M.; Unterberg, E. A.; Watkins, J.

    2016-09-01

    Bulk ion toroidal velocity profiles, V| | D + , peaking at 40-60 km/s are observed with Mach probes in a narrow edge region of DIII-D discharges without external momentum input. This intrinsic rotation can be well reproduced by a first principle, collisionless kinetic loss model of thermal ion loss that predicts the existence of a loss-cone distribution in velocity space resulting in a co-Ip directed velocity. We consider two kinetic models, one of which includes turbulence-enhanced momentum transport, as well as the Pfirsch-Schluter (P-S) fluid mechanism. We measure a fine structure of the boundary radial electric field, Er, insofar ignored, featuring large (10-20 kV/m) positive peaks in the scrape off layer (SOL) at, or slightly inside, the last closed flux surface of these low power L- and H-mode discharges in DIII-D. The Er structure significantly affects the ion-loss model, extended to account for a non-uniform electric field. We also find that V| | D + is reduced when the magnetic topology is changed from lower single null to upper single null. The kinetic ion loss model containing turbulence-enhanced momentum transport can explain the reduction, as we find that the potential fluctuations decay with radius, while we need to invoke a topology-enhanced collisionality on the simpler kinetic model. The P-S mechanism fails to reproduce the damping. We show a clear correlation between the near core V| | C 6 + velocity and the peak edge V| | D + in discharges with no external torque, further supporting the hypothesis that ion loss is the source for intrinsic torque in the present tokamaks. However, we also show that when external torque is injected in the core, it can complete with, and eventually overwhelm, the edge source, thus determining the near SOL flows. Finally, we show some additional evidence that the ion/electron distribution in the SOL is non-Maxwellian.

  3. A model to predict CWD residence times in tropical forests along an altitudinal gradient in Australia

    Science.gov (United States)

    Torello-Raventos, Mireia; Ford, Andrew; Saiz, Gus; Bloomfield, Keith; Lloyd, Jon; Bird, Michael

    2014-05-01

    More reliable knowledge on the complex responses of vegetation to climate change is one of the most urgent needs for tropical forest preservation and recent data models indicate an increase of tree mortality in tropical forests as a consequence of climate change1. Coarse woody debris dynamics in tropical forests remain poorly understood2. Tropical forests are known for possessing a wide range of wood densities- with different wood traits and secondary wood chemical components-, adding complexity to the accurate estimations of coarse woody debris residence times (τ). Quantifying τ in these ecosystems along an altitudinal gradient provides a way to improve our understanding of carbon dynamics in the face of climate change. This study examines τ from different tree tropical forest species -ranging from soft to hardwoods- and under different decay status, to understand the effects of climate on the chemical and physical decay of CWD on an elevation gradient from 102 m above sea level (MAT = 23.7° C) to 1500 m above sea level (MAT = 16.7° C) in Australia. Wood density together with Carbon:Nitrogen ratio enabled prediction of the variation in τ between decay classes within tree species, between tree species and along the elevation gradient. τ increased with decreasing the decay status, increasing wood density and temperature also played an important role as τ increased with increasing site elevation. The study also highlighted the importance of including seasonal variation of climate in short term field studies, as a single wet season reduced the τ of the CWD compared to τ after a year of exposure. Intraspecific variation of plant traits and secondary wood chemicals explained the observed range in τ for species with similar wood densities, decreasing with increasing decayed status of the samples. This study will aid in the development of predictive relationships between wood density and environmental variables to infer carbon dynamics at local and global scale

  4. Grain yield losses in yellow-rusted durum wheat estimated using digital and conventional parameters under field conditions

    Institute of Scientific and Technical Information of China (English)

    Omar; Vergara-Diaz; Shawn; C.Kefauver; Abdelhalim; Elazab; Maria; Teresa; Nieto-Taladriz; José; Luis; Araus

    2015-01-01

    The biotrophic fungus Puccinia striiformis f. sp. tritici is the causal agent of the yellow rust in wheat. Between the years 2010–2013 a new strain of this pathogen(Warrior/Ambition),against which the present cultivated wheat varieties have no resistance, appeared and spread rapidly. It threatens cereal production in most of Europe. The search for sources of resistance to this strain is proposed as the most efficient and safe solution to ensure high grain production. This will be helped by the development of high performance and low cost techniques for field phenotyping. In this study we analyzed vegetation indices in the Red,Green, Blue(RGB) images of crop canopies under field conditions. We evaluated their accuracy in predicting grain yield and assessing disease severity in comparison to other field measurements including the Normalized Difference Vegetation Index(NDVI), leaf chlorophyll content, stomatal conductance, and canopy temperature. We also discuss yield components and agronomic parameters in relation to grain yield and disease severity.RGB-based indices proved to be accurate predictors of grain yield and grain yield losses associated with yellow rust(R2= 0.581 and R2= 0.536, respectively), far surpassing the predictive ability of NDVI(R2= 0.118 and R2= 0.128, respectively). In comparison to potential yield, we found the presence of disease to be correlated with reductions in the number of grains per spike, grains per square meter, kernel weight and harvest index. Grain yield losses in the presence of yellow rust were also greater in later heading varieties. The combination of RGB-based indices and days to heading together explained 70.9% of the variability in grain yield and 62.7% of the yield losses.

  5. Grain yield losses in yellow-rusted durum wheat estimated using digital and conventional parameters under field conditions

    Institute of Scientific and Technical Information of China (English)

    Omar Vergara-Diaz; Shawn C. Kefauver; Abdelhalim Elazab; Maria Teresa Nieto-Taladriz; José Luis Araus

    2015-01-01

    The biotrophic fungus Puccinia striiformis f. sp. tritici is the causal agent of the yellow rust in wheat. Between the years 2010–2013 a new strain of this pathogen (Warrior/Ambition), against which the present cultivated wheat varieties have no resistance, appeared and spread rapidly. It threatens cereal production in most of Europe. The search for sources of resistance to this strain is proposed as the most efficient and safe solution to ensure high grain production. This will be helped by the development of high performance and low cost techniques for field phenotyping. In this study we analyzed vegetation indices in the Red, Green, Blue (RGB) images of crop canopies under field conditions. We evaluated their accuracy in predicting grain yield and assessing disease severity in comparison to other field measurements including the Normalized Difference Vegetation Index (NDVI), leaf chlorophyll content, stomatal conductance, and canopy temperature. We also discuss yield components and agronomic parameters in relation to grain yield and disease severity. RGB-based indices proved to be accurate predictors of grain yield and grain yield losses associated with yellow rust (R2=0.581 and R2=0.536, respectively), far surpassing the predictive ability of NDVI (R2=0.118 and R2=0.128, respectively). In comparison to potential yield, we found the presence of disease to be correlated with reductions in the number of grains per spike, grains per square meter, kernel weight and harvest index. Grain yield losses in the presence of yellow rust were also greater in later heading varieties. The combination of RGB-based indices and days to heading together explained 70.9% of the variability in grain yield and 62.7%of the yield losses.

  6. Visual Field Loss in a Case of Recurrent Cystic Craniopharyngioma During Concomitant Treatment With Pegylated Interferon α-2b.

    Science.gov (United States)

    Tiedemann, Laura M; Manley, Peter; Smith, Edward R; Dagi, Linda R

    2016-01-01

    A 13-year-old male with suprasellar cystic craniopharyngioma initially controlled with sequential subtotal resections and proton-beam irradiation was later treated with intracystic pegylated interferon α-2b due to progression and a lack of further surgical options. After initial successful control of recurrent cyst enlargement and stabilization of the ophthalmic examination, progressive and irreversible visual field loss ensued. Imaging revealed intracranial leakage from the intracystic catheter, and direct administration of interferon α-2b was discontinued. Given the recent interest in interferon α-2b, oncologists are advised to vigilantly monitor patients for signs of local toxicity that may result from unintended leakage during intracystic delivery.

  7. Edge of Field Nitrate Loss and Oxygen-18 Dynamics in a Dryland Agriculture Setting

    Science.gov (United States)

    Wannamaker, C. N.; Goodwin, A. J.; Keller, C.; Allen-King, R.; Smith, J. L.

    2004-12-01

    Four complete water years of nitrate concentrations and oxygen isotope (δ O18) ratios have been monitored in a tile drain and adjacent soil-water sampling lysimeters beneath a dryland, agricultural field in the Palouse Region of Washington State, USA. The Palouse is semi-arid and is characterized by undulating loess hills and swales drained by ephemeral to perennial streams. Soil type is dominated by silt-loam Mollisols. Our field is subject to typical farming practices and crop rotations, receiving ammonia fertilizer during fall and spring planting at a rate of ˜70kg of nitrogen per acre. Tile drains play an essential role in environmental nitrogen dynamics in this region as they are widely utilized to drain water from lower fields. Nitrate concentrations in tile drainage fluctuate on a seasonal basis ranging from low concentrations of ˜1mg/ NO3-N/L in late October/November to higher concentrations of 20-30mg NO3-N/L in late January/February. Rise in concentration occurs rapidly with the onset of high flow conditions differing from a typical dilution effect. Lysimeter waters show similar nitrate patterns ranging in concentration from ~10mg NO3-N/L to as high as 120mg NO3-N/L. In the lysimeters, nitrate concentrations are apparently positively correlated with δ O18 values. Precipitation collected at the field site shows a 12 per mil seasonal variation in δ O18. A seasonal pattern is also observed in soil water with a smaller range of about 6 per mil. These seasonal fluctuations are not observed in tile drainage, where values vary only 2 per mil with a mean of -15 per ml. We hypothesize that residence-time and scaling effects can explain the δ O18 fluctuation differences between soil water and tile drainage. The very large nitrate fluctuations throughout the system may be due in part to the seasonality of soil nitrogen cycling.

  8. Losses of heat and particles in the presence of strong magnetic field perturbations

    OpenAIRE

    Gupta, Abhinav

    2009-01-01

    Thermonuclear fusion has potential to offer an economically, environmentally and socially acceptable supply of energy. A promising reactor design to execute thermonuclear fusion is the toroidal magnetic confinement device, tokamak. The tokamak still faces challenges in the major areas which can be categorised into confinement, heating and fusion technology. This thesis addresses the problem of confinement, in particular the role of transport along magnetic field lines perturbed by diverse MHD...

  9. Hearing loss and potential hazards of metallic middle-ear implants in NMR-magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Huettenbrink, K.B.

    1987-08-01

    Concurrent with the expanding clinical applications of nuclear magnetic resonance (NMR) imaging, patients with metallic middle-ear implants will certainly be exposed to this strong magnetic field in the future. To determine potential hazards, associated with movements of steel- or Platinium stapes-prostheses, several tests were performed in a 0.5 tesla NMR unit and the induced forces were calculated. Although the commonly used paramagnetic steel-wire or platinium-alloys will not dislodge in vivo, ferromagnetic prostheses may present a hazardous risk. Prior to exposure to the magnetic field, information about the implanted material should therefore be obtained. A side-effect of the induced current flow is the attenuation of the sound-vibrations of the stapes prosthesis. This, 5-10 dB impairment of transmission develops only at a certain position of the patient's head, when the prosthesis vibrates perpendicularly to the magnetic field's Z-axis. Patients with a metallic prosthesis should be informed about this purely physical, harmless phenomenon prior to entering the NMR-cylinder.

  10. Long term dynamics of nitrate concentrations and leaching losses in tile drainage water from cultivated clayey till at field scale

    DEFF Research Database (Denmark)

    Ernstsen, Vibeke; Olsen, Preben; Rosenbom, Annette Elisabeth;

    2014-01-01

    of regulations will require very detailed information concerning e.g. climate, soil, geological settings, and hydrological conditions. The purpose of this study was to investigate the contribution of nitrate (concentrations and losses) from drainage water at three fields (1.3-2.3 ha) located across Denmark.......g. climate, soil type and local hydraulic conditions. By the end of 2013, the Danish Commission of Nature and Agriculture issued a report which recommend that for the future protection of surface nitrogen regulations should be locally adapted, and if possible, at the level of field scale. This kind...... varying in climate, soil type and geology. Each site, is systematically subsurface tile drained in a depth of about 1.1 meters and with a horizontal spacing of 18-20 meters. On each site detailed information are recorded regarding crop development, tillage, N-fertilization (amount, type and time...

  11. Soil Organic Carbon Loss and Turnover Resulting from Forest Conversion to Maize Fields in Eastern Thailand

    Institute of Scientific and Technical Information of China (English)

    S. JAIARREE; A. CHIDTHAISONG; N. TANGTHAM; C. POLPRASERT; E. SAROBOL; S. C. TYLER

    2011-01-01

    Soil organic carbon (SOC) content and its stable carbon isotopic composition (within the upper 1 m) were measured to determine the effect of land-use changes from dry evergreen forest to maize fields in eastern Thailand.Digital land cover maps,derived from aerial photography and satellite images for years 1989,1996,and 2002 were used in association with field surveys and farmer interviews to derive land-use history and to assist in study site selection.Conversion from forest to maize cultivation for the duration of 12 years reduced SOC stocks at the rate of 6.97 Mg C ha-1 year-1.Reduction was most pronounced in the top 10 cm soil layer,which was 47% after 12 years of cultivation.Stable carbon isotope data revealed that the main fraction lost was forest-derived C.Generally low input rates of maize-derived C were not sufficient to maintain SOC at the level prior to forest conversion.After 12 years of continuous maize cultivation,the maize-derived C fraction made up about 20% of total SOC (5 Mg ha-1 of the total 25.31 Mg ha-1).

  12. Dominance of an invasive fruit fly species, Bactrocera invadens, along an altitudinal transect in Morogoro, Eastern Central Tanzania.

    Science.gov (United States)

    Geurts, K; Mwatawala, M W; De Meyer, M

    2014-06-01

    Bactrocera invadens, a fruit fly from Asia, is an invasive pest species across Africa. It appears to continue spreading, not only in latitude but also in altitude. To assess its capacity to infest a large variety of hosts and its competition with other fruit fly species, a study along an altitudinal gradient was conducted. At low altitudes, the high abundance in the field and high infestation of B. invadens in different fruit species make it a serious pest. At high altitudes, colonization has started and B. invadens occurs in low numbers by reproducing successfully in high altitude fruits. Overall the abundance and infestation of B. invadens is influenced by its direct competitor Ceratitis rosa and the presence of its preferred host species. C. rosa is still the dominant species in temperate fruits grown at high altitude. Ceratitis cosyra, however, is negatively affected by B. invadens, this species seems to have shifted hosts to avoid competition. The broad host range and competitive potential of B. invadens increase the risk for further spread not only to higher areas, but also to subtropical regions.

  13. Mass-Loss Timescale of Star Clusters in an External Tidal Field. II. Effect of Mass Profile of Parent Galaxy

    CERN Document Server

    Tanikawa, Ataru

    2010-01-01

    We investigate the long-term dynamical evolution of star clusters in a steady tidal field produced by its parent galaxy. In this paper, we focus on the influence of mass profile of the parent galaxy. The previous studies were done with the simplification where the parent galaxy was expressed by point mass. We express different mass profiles of the parent galaxy by the tidal fields in which the ratios of the epicyclic frequency to the angular velocity are different. We compare the mass-loss timescale of star clusters whose tidal radii are identical but in parent galaxies with different mass profile, by means of orbits calculations in fixed cluster potential and N-body simulations. In this situation, a cluster rotates around the parent galaxy more rapidly as the parent galaxy has shallower mass profile. We found that the mass-loss timescale increase 20% and 50% for the cases that the mass density profile of the parent galaxies are proportional to R^-2 and R^-1.5 where R is the distance from the galaxy center, c...

  14. Biological transfer and loss of 36Cl-labeled DDT in an old-field ecosystem

    International Nuclear Information System (INIS)

    An enclosed 10-acre old-field plot treated in June 1969, with chlorine-36 labeled DDT was sampled each year from 1969 through 1974 to monitor the fate of the insecticide in the soil and biota. In order to provide data on compartmentalization of DDT in the vegetation, invertebrates and vertebrates inhabiting the plot, sampling was carried out to estimate both body burdens of DDT and biomass of populations. Another aspect of this study, the determination of rates of accumulation of residues by invertebrates and vertebrates, has been reported previously (Forsyth and Peterle 1973; Forsyth et al. 1975; Peterle 1975). This report describes (a) temporal patterns of DDT residues in soil and biota from 1969 through 1974 and (b) quantities of DDT held in the soil and biotic compartments of the ecosystem. Part II of the report is concerned with translocation and accumulation of14C-DDT

  15. Quantifying ecosystem carbon losses and gains following development in New England: A combined field, modeling, and remote sensing approach

    Science.gov (United States)

    Raciti, S. M.; Hutyra, L.; Briber, B. M.; Dunn, A. L.; Friedl, M. A.; Woodcock, C.; Zhu, Z.; Olofsson, P.

    2013-12-01

    If current trends continue, the world's urban population may double and urban land area may quadruple over the next 50 years. Despite the rapid expansion of urban areas, the trajectories of carbon losses and gains following development remain poorly quantified. We are using a combination of field measurements, modeling, and remote sensing to advance our ability to measure and monitor trajectories of ecosystem carbon over space and time. To characterize how carbon stocks change across urban-to-rural gradients, we previously established field plots to survey live and dead tree biomass, tree canopy, soil and foliar carbon and nitrogen concentrations, and a range of landscape characteristics (Raciti et al. 2012). In 2013, we extended our field sampling to focus specifically on places that experienced land use and land cover change over the past 35 years. This chronosequence approach was informed by Landsat time series (1982-present) and property records (before 1982). The Landsat time series approach differs from traditional remote-sensing-based land use change detection methods because it leverages the entire Landsat archive of imagery using a Fourier fitting approach (Zhu et al. 2012). The result is a temporally and spatially continuous map of land use and land cover change across the study region. We used these field and remote sensing data to inform a carbon bookkeeping model that estimates changes in past and potential future carbon stocks over time. Here we present preliminary results of this work for eastern Massachusetts.

  16. Charge Losses in Silicon Sensors and Electric-Field Studies at the Si-SiO$_2$ Interface

    CERN Document Server

    Poehlsen, Thomas

    Electric fields and charge losses in silicon sensors before and after irradiation with x-rays, protons, neutrons or mixed irradiation are studied in charge-collection measurements. Electron-hole pairs ($eh$ pairs) are generated at different positions in the sensor using sub-ns pulsed laser light of different wavelengths. Light of 1063 nm, 830 nm and 660 nm wavelength is used to generate $eh$ pairs along the whole sensor depth, a few $\\mu$m below the surface and very close to the surface, respectively. Segmented p$^+$n silicon strip sensors are used to study the electric field below the SiO$_2$ separating the strip implants. The sensors are investigated before and after irradiation with 12 keV x-rays to a dose of 1 MGy. It is found that the electric field close to the Si-SiO$_2$ interface depends on both the irradiation dose and the biasing history. For the non-irradiated sensors the observed dependence of the electric field on biasing history and humidity is qualitatively as expected from simulations of the...

  17. Soil organic carbon loss and selective transportation under field simulated rainfall events.

    Directory of Open Access Journals (Sweden)

    Xiaodong Nie

    Full Text Available The study on the lateral movement of soil organic carbon (SOC during soil erosion can improve the understanding of global carbon budget. Simulated rainfall experiments on small field plots were conducted to investigate the SOC lateral movement under different rainfall intensities and tillage practices. Two rainfall intensities (High intensity (HI and Low intensity (LI and two tillage practices (No tillage (NT and Conventional tillage (CT were maintained on three plots (2 m width × 5 m length: HI-NT, LI-NT and LI-CT. The rainfall lasted 60 minutes after the runoff generated, the sediment yield and runoff volume were measured and sampled at 6-min intervals. SOC concentration of sediment and runoff as well as the sediment particle size distribution were measured. The results showed that most of the eroded organic carbon (OC was lost in form of sediment-bound organic carbon in all events. The amount of lost SOC in LI-NT event was 12.76 times greater than that in LI-CT event, whereas this measure in HI-NT event was 3.25 times greater than that in LI-NT event. These results suggest that conventional tillage as well as lower rainfall intensity can reduce the amount of lost SOC during short-term soil erosion. Meanwhile, the eroded sediment in all events was enriched in OC, and higher enrichment ratio of OC (ERoc in sediment was observed in LI events than that in HI event, whereas similar ERoc curves were found in LI-CT and LI-NT events. Furthermore, significant correlations between ERoc and different size sediment particles were only observed in HI-NT event. This indicates that the enrichment of OC is dependent on the erosion process, and the specific enrichment mechanisms with respect to different erosion processes should be studied in future.

  18. Distribution of Soil Organic Carbon Fractions Along the Altitudinal Gradient in Changbai Mountain, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Min; ZHANG Xiao-Ke; LIANG Wen-Ju; JIANG Yong; DAI Guan-Hua; WANG Xu-Gao; HAN Shi-Jie

    2011-01-01

    Understanding the responses of soil organic carbon (SOC) fractions to altitudinal gradient variation is important for understanding changes in the carbon balance of forest ecosystems.In our study the SOC and its fractions of readily oxidizable carbon (ROC),water-soluble carbon (WSC) and microbial biomass carbon (MBC) in the soil organic and mineral horizons were investigated for four typical forest types,including mixed coniferous broad-leaved forest (MCB),dark coniferous spruce-fir forest (DCSF),dark coniferous spruce forest (DCS),and Ermans birch forest (EB),along an altitudinal gradient in the Changbai Mountain Nature Reserve in Northeast China.The results showed that there was no obvious altitudinal pattern in the SOC.Similar variation trends of SOC with altitude were observed between the organic and mineral horizons.Significant differences in the contents of SOC,WSC,MBC and ROC were found among the four forest types and between horizons.The contents of ROC in the mineral horizon,WSC in the organic horizon and MBC in both horizons in the MCB and EB forests were significantly greater than those in either DCSF or DCS forest.The proportion of soil WSC to SOC was the lowest among the three main fractions.The contents of WSC,MBC and ROC were significantly correlated (P < 0.05) with SOC content.It can be concluded that vegetation types and climate were crucial factors in regulating the distribution of soil organic carbon fractious in Changbai Mountain.

  19. Gene regulatory variation mediates flowering responses to vernalization along an altitudinal gradient in Arabidopsis.

    Science.gov (United States)

    Suter, Léonie; Rüegg, Marlene; Zemp, Niklaus; Hennig, Lars; Widmer, Alex

    2014-12-01

    Steep environmental gradients provide ideal settings for studies of potentially adaptive phenotypic and genetic variation in plants. The accurate timing of flowering is crucial for reproductive success and is regulated by several pathways, including the vernalization pathway. Among the numerous genes known to enable flowering in response to vernalization, the most prominent is FLOWERING LOCUS C (FLC). FLC and other genes of the vernalization pathway vary extensively among natural populations and are thus candidates for the adaptation of flowering time to environmental gradients such as altitude. We used 15 natural Arabidopsis (Arabidopsis thaliana) genotypes originating from an altitudinal gradient (800-2,700 m above sea level) in the Swiss Alps to test whether flowering time correlated with altitude under different vernalization scenarios. Additionally, we measured the expression of 12 genes of the vernalization pathway and its downstream targets. Flowering time correlated with altitude in a nonlinear manner for vernalized plants. Flowering time could be explained by the expression and regulation of the vernalization pathway, most notably by AGAMOUS LIKE19 (AGL19), FLOWERING LOCUS T (FT), and FLC. The expression of AGL19, FT, and VERNALIZATION INSENSITIVE3 was associated with altitude, and the regulation of MADS AFFECTING FLOWERING2 (MAF2) and MAF3 differed between low- and high-altitude genotypes. In conclusion, we found clinal variation across an altitudinal gradient both in flowering time and the expression and regulation of genes in the flowering time control network, often independent of FLC, suggesting that the timing of flowering may contribute to altitudinal adaptation. PMID:25339407

  20. Temporal and altitudinal variations in benthic macroinvertebrate assemblages in an Andean river basin of Argentina

    Directory of Open Access Journals (Sweden)

    Erica E. Scheibler

    2014-02-01

    Full Text Available Environmental variables and benthic macroinvertebrate assemblages were spatially and seasonally examined over two consecutive years (2000-2002 along a glacier and snowmelt river in the central-west of Argentina where lies the highest peak in America, Mount Aconcagua (6956 m elevation. The goal was to assess seasonal and altitudinal variability in benthic community structure and to define whether physical-chemical variables affect distribution of aquatic insects. The Mendoza river basin was characterised by high variability in flow and transparency, high conductivity, hard calcium sulphate water, neutral and alkaline pH, and dominant substrate composed of small blocks, cobbles, pebbles, and sand-silt. Richness of invertebrates was low, with the lowest taxonomic richness being recorded at the mouth. The dominant group with highest taxonomic richness was Diptera, although caddisflies, mayflies, beetles, and stoneflies were present. Seasonal and spatial variations in biotic and abiotic variables were detected. Maximal densities and taxonomic richness were recorded in autumn and winter. From Modified Morisita’s Cluster analysis it was found that the system is divided into two groupings of sites related to each other by faunal composition. INDVAL revealed species turnover along the altitudinal gradient of some taxa: Andesiops, Massartellopsis, Edwarsina, Chelifera, and Ceratopogonidae had preference for the headwaters (2835-2425 m elevation, Smicridea murina and Baetodes for the lower section (1413-1085 m elevation, and Austrelmis for the middle and lower sections. The middle section (1846-1727 m elevation was a transition area where taxa from the headwaters and the lower section coexisted. Generalised Linear Models evidenced that altitude was the major factor determining macroinvertebrate assemblages along the large arid Mendoza River and that the physical-chemical variables that most influenced variation in community structure were: transparency

  1. EVALUATION OF BIOAGENTS FOR MANAGEMENT OF THE ONION PURPLE BLOTCH AND BULB YIELD LOSS ASSESSMENT UNDER FIELD CONDITIONS

    Directory of Open Access Journals (Sweden)

    P. M. YADAV

    2014-03-01

    Full Text Available Among the several diseases, purple blotch diseases of onion (Allium cepa L. caused by Alternaria porri (Ellis Cif. is one of the most destructive disease causing accountable losses of about 80 to 90 per cent. The results obtained on the field efficacy of different bioagents tested, Pseudomonas fluorescens--I (0.5% was found most antifungal against A. porri and recorded significantly least mean disease intensity (37.19% and gave maximum bulb yield (27183 kg/ha. Both the fungal and bacterial antagonists tested were also found effective against A. porri and recorded significantly reduced mean disease intensity thereby increased the bulb yield over unsprayed control. Based on incremental cost:benefit ratio (ICBR of the bioagents spray treatments, P. fluorescens--I (ICBR, 1:13.87 was found economical and effective for the management of purple blotch of onion followed by Bacillus subtilis (ICBR, 1:12.93.

  2. Growth response of Larix hybrids between L. kaempferi and L. gmelinii var. japonica with altitudinal gradient

    Energy Technology Data Exchange (ETDEWEB)

    Kisanuki, Hiromitsu; Kurahashi, Akio; Takahashi, Yasuo [Tokyo Univ. Forest, Hokkaido (Japan)

    1995-12-31

    To test the adaptability of Japanese larch, Dahurian larch and their hybrid to the environment in Hokkaido, these three materials were planted and surveyed of their survival and growth for 30 years at four elevation in central Hokkaido, northern Japan. Japanese larch showed low adaptation with high mortality affected by voles at every elevation. Dahurian larch has high vole resistance but showed high mortality caused by the infection of Armillaria root rot. Hybrid could persist through low to high elevation. Only hybrid showed enough growth at the highest elevation. Stress tolerance of hybrid was confirmed under high altitudinal condition. 12 refs, 4 figs, 3 tabs

  3. Altitudinal Pattern of Plant Species Diversity in Shennongjia Mountains, Central China

    Institute of Scientific and Technical Information of China (English)

    Chang-Ming ZHAO; Wei-Lie CHEN; Zi-Qiang TIAN; Zong-Qiang XIE

    2005-01-01

    One hundred and sixty plots, approximately every 100 m above sea level (a.s.l.) along an altitudinal gradient from 470 to 3 080 m a.s.l, at the southern and northern watershed of Mt. Shennongjia,China, were examined to determine the altitudinal pattern of plant species diversity. Mt. Shennongjia was found to have high plant species diversity, with 3 479 higher plants recorded. Partial correlation analysis and detrended canonical correspondence analysis (DCCA) based on plant species diversity revealed that altitude was the main factor affecting the spatial pattern of plant species diversity on Mt. Shennongjia and that canopy coverage of the arbor layer also had a considerable effect on plant species diversity. The DCCA based on species data of importance value further revealed that altitude gradient was the primary factor shaping the spatial pattern of plant species. In addition, the rule of the "mid-altitude bulge" was supported on Mt. Shennongjia. Plant species diversity was closely related to vegetation type and the transition zone usually had a higher diversity. Higher plant species diversity appeared in the mixed evergreen and deciduous broadleaved forest zone (900-1 500 m a.s.l.) and its transition down to evergreen broadleaved forest zone or up to deciduous broadleaved forest zone. The largest plant species diversity in whole communities on Mt. Shennongjia lay at approximately 1 200 m a.s.l. Greatest tree diversity, shrub diversity, and grass diversity was found at approximately 1 500, 1 100, and 1 200 m a.s.l., respectively. The southern watershed showed higher plant species diversity than the northern watershed, with maximum plant species diversity at a higher altitude in the southern watershed than the northern watershed. These results indicate that Mt.Shennongjia shows characteristics of a transition region. The relationship between the altitudinal pattern of plant species diversity and the vegetation type in eastern China are also discussed and a

  4. Efficacy of drinking-water treatment residual in controlling off-site phosphorus losses: a field study in Florida.

    Science.gov (United States)

    Agyin-Birikorang, S; Oladeji, O O; O'Connor, G A; Obreza, T A; Capece, J C

    2009-01-01

    Land application of drinking-water treatment residuals (WTR) has been shown to control excess soil soluble P and can reduce off-site P losses to surface and ground water. To our knowledge, no field study has directly evaluated the impacts of land application of WTRs on ground water quality. We monitored the effects of three organic sources of P (poultry manure, Boca Raton biosolids, Pompano biosolids) or triple superphosphate co-applied with an aluminum-based WTR (Al-WTR) on soil and ground water P and Al concentrations under natural field conditions for 20 mo in a soil with limited P sorption capacity. The P sources were applied at two rates (based on P or nitrogen [N] requirement of bahiagrass) with or without Al-WTR amendment and replicated three times. Without WTR application, applied P sources increased surface soil soluble P concentrations regardless of the P source or application rate. Co-applying the P sources with Al-WTR prevented increases in surface soil soluble P concentrations and reduced P losses to shallow ground water. Total dissolved P and orthophosphate concentrations of shallow well ground water of the N-based treatments were greater (>0.9 and 0.3 mg L(-1), respectively) in the absence than in the presence ( approximately 0.6 and 0.2 mg L(-1), respectively) of Al-WTR. The P-based application rate did not increase ground water P concentrations relative to background concentrations. Notwithstanding, Al-WTR amendment decreased ground water P concentrations from soil receiving treatments with P-based application rates. Ground water total dissolved Al concentrations were unaffected by soil Al-WTR application. We conclude that, at least for the study period, Al-WTR can be safely used to reduce P leaching into ground water without increasing the Al concentration of ground water. PMID:19329695

  5. Hysteresis losses in MgB{sub 2} superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, N., E-mail: niklas.magnusson@sintef.no [SINTEF Energy Research, NO-7465 Trondheim (Norway); Abrahamsen, A.B. [DTU Wind Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Liu, D. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands); Runde, M. [SINTEF Energy Research, NO-7465 Trondheim (Norway); Polinder, H. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands)

    2014-11-15

    Highlights: • A method for calculating hysteresis losses in the low AC – high DC magnetic field and transport current range has been shown. • The method can be used in the design of wind turbine generators for calculating the losses in the generator DC rotor. • First estimates indicate tolerable current ripple in the 0.1% range for a 4 T DC MgB{sub 2} generator rotor coil. - Abstract: MgB{sub 2} superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB{sub 2} conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB{sub 2} DC coils in the 1–4 T range with low AC magnetic field and current ripples.

  6. Applying theories and interventions from behavioral medicine to understand and reduce visual field variability in patients with vision loss.

    Science.gov (United States)

    Rozanski, Collin; Haythornthwaite, Jennifer A; Dagnelie, Gislin; Bittner, Ava K

    2014-08-01

    Visual field (VF) test results are often unreliable in visually impaired patients, but continue to be a cornerstone of clinical trials and play a vital role in clinical decision making since they are the primary method to determine patients' functional vision loss or progression. Currently, patients are typically asked to perform VF tasks with minimal instruction or consideration of their psychological experience during the test. The gradual loss of vision due to retinal diseases, such as retinitis pigmentosa (RP), age-related macular degeneration (AMD), or glaucoma can contribute to the experience of negative psychosocial states, such as anxiety, stress, and depression, as well as diminished quality of life. We hypothesize that VF testing elicits test performance anxiety and perception of functional losses of vision, which induces distracting negative thoughts that result in increased VF test variability. Resources for processing and responding to vision-related information may be diverted from task-relevant VF stimuli to task-irrelevant ones, such as internal worry and test anxiety, thereby resulting in VF test performance decrements. We present a theoretical model to support the hypothesis that VF variability is linked to patients' negative thoughts during VF testing. This conceptual framework provides a basis for the development of coping strategies and mindfulness-based interventions to be evaluated in future research aimed at improving psychosocial states and VF reliability in visually-impaired patients. It would be highly significant to intervene by modifying negative thoughts during VF testing to reduce test variability in glaucoma patients who are progressively losing vision to a blinding eye disease, but whose vision loss has not been accurately identified and treated early enough due to variable VF results. In clinical trials of potential interventions for RP and non-neovascular AMD, reducing VF variability would effectively increase the precision for

  7. Climate change and frog calls: long-term correlations along a tropical altitudinal gradient.

    Science.gov (United States)

    Narins, Peter M; Meenderink, Sebastiaan W F

    2014-05-22

    Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs' calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest. PMID:24718765

  8. Replicate altitudinal clines reveal that evolutionary flexibility underlies adaptation to drought stress in annual Mimulus guttatus.

    Science.gov (United States)

    Kooyers, Nicholas J; Greenlee, Anna B; Colicchio, Jack M; Oh, Morgan; Blackman, Benjamin K

    2015-04-01

    Examining how morphology, life history and physiology vary along environmental clines can reveal functional insight into adaptations to climate and thus inform predictions about evolutionary responses to global change. Widespread species occurring over latitudinal and altitudinal gradients in seasonal water availability are excellent systems for investigating multivariate adaptation to drought stress. Under common garden conditions, we characterized variation in 27 traits for 52 annual populations of Mimulus guttatus sampled from 10 altitudinal transects. We also assessed variation in the critical photoperiod for flowering and surveyed neutral genetic markers to control for demography when analyzing clinal patterns. Many drought escape (e.g. flowering time) and drought avoidance (e.g. specific leaf area, succulence) traits exhibited geographic or climatic clines, which often remained significant after accounting for population structure. Critical photoperiod and flowering time in glasshouse conditions followed distinct clinal patterns, indicating different aspects of seasonal phenology confer adaptation to unique agents of selection. Although escape and avoidance traits were negatively correlated range-wide, populations from sites with short growing seasons produced both early flowering and dehydration avoidance phenotypes. Our results highlight how abundant genetic variation in the component traits that build multivariate adaptations to drought stress provides flexibility for intraspecific adaptation to diverse climates. PMID:25407964

  9. Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera

    Directory of Open Access Journals (Sweden)

    Sarah Maveety

    2011-11-01

    Full Text Available Carabid beetles were sampled at five sites, ranging from 1500 m to 3400 m, along a 15 km transect in the cloud forest of Manu National Park, Perú. Seasonal collections during a one year period yielded 77 morphospecies, of which 60% are projected to be undescribed species. There was a significant negative correlation between species richness and altitude, with the number of carabid species declining at the rate of one species for each 100 m increase in altitude. The majority of species (70.1 % were restricted to only one altitudinal site and no species was found at more than three of the five altitudinal sites. Only one genus, Pelmatellus (Tribe Harpalini, was found at all five sites. Active (hand collections yielded approximately twice as many species per individuals collected than passive (pitfall trap collections. This study is the first systematic sampling of carabid beetles of a high altitude gradient in the cloud forests of southeastern Perú and supports the need to conserve the zone of extremely high biodiversity present on the eastern slopes of the Peruvian Andes.

  10. Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera).

    Science.gov (United States)

    Maveety, Sarah A; Browne, Robert A; Erwin, Terry L

    2011-01-01

    Carabid beetles were sampled at five sites, ranging from 1500 m to 3400 m, along a 15 km transect in the cloud forest of Manu National Park, Perú. Seasonal collections during a one year period yielded 77 morphospecies, of which 60% are projected to be undescribed species. There was a significant negative correlation between species richness and altitude, with the number of carabid species declining at the rate of one species for each 100 m increase in altitude. The majority of species (70.1 %) were restricted to only one altitudinal site and no species was found at more than three of the five altitudinal sites. Only one genus, Pelmatellus (Tribe Harpalini), was found at all five sites. Active (hand) collections yielded approximately twice as many species per individuals collected than passive (pitfall trap) collections. This study is the first systematic sampling ofcarabid beetles of a high altitude gradient in the cloud forests of southeastern Perú and supports the need to conserve the zone of extremely high biodiversity present on the eastern slopes of the Peruvian Andes. PMID:22371680

  11. Dendroclimatic response of Picea jezoensis along an altitudinal gradient in Changbai Mountains

    Institute of Scientific and Technical Information of China (English)

    YU; Dapao; WANG; Qingli; G.; Geoff; Wang; DAI; Limin

    2006-01-01

    We investigated the effects of climate on Yeddo spruce (Picea jezoensis)radial growth along altitudinal gradients in the subalpine forests of Changbai Mountains using dendroclimatic analyses. Yeddo spruce at its lower and upper distribution limits was more sensitive to the climate. Despite precipitation being generally considered sufficient, we found that precipitation significantly affected Yeddo spruce radial growth. Yeddo spruce at its lower distribution limit was much more affected by precipitation while Yeddo spruce at its upper distribution limit was much more affected by minimum temperature. Yeddo spruce at its medial altitude was affected by sunshine ratio. These results demonstrated that climate affected Yeddo spruce growth differently depending on its altitudinal distributions in the Changbai Mountains. Both temperature and precipitation in the annualization period significantly correlated with Yeddo spruce radial growth. However, warmer signals were not reflected in radial growth trend during the past 20 years because annual total precipitation declined during the same period. It appeared that the climate affected tree rings growth by altering soil moisture availability.

  12. Effects of the radial electric field resonances on the particle orbits and loss cones in TJ-II

    International Nuclear Information System (INIS)

    The effects of the radial electric field resonances on the trapping and confinement of low and intermediate energy ions (0.1-1 keV) for the Reference configuration of TJ-II have been analysed. In TJ-II these resonances appear for electric potentials that grow with pitch and with the square root of the initial kinetic energy and are placed inside strips whose width increases with the initial radius and with the absolute value of initial pitch. The 0-Resonance is the most important one for particle trapping, it appears for high electric potential (between 1000 and 3000 V for 0.5 keV ions) with the same sign than pitch, inside very wide strips (several thousands of V). Along these band periphery, for potential intensities below the central resonant values, there exists a very strong increase of particle trapping. Instead, around the resonance center, the trapping is inhibited and a very strong increase of the passing particle population appears. This increase is higher for the torus external side (Theta approximately 0 degree centigree) and for small initial radius. For peripherical particles wide loss strips appear along the border of the resonant band corresponding to more positive potential. The 2-Resonance has small effect on trapping but affects strongly to the of peripherical passing particles. It appears for moderate electric potential (between 400 and 1000 V for 0.5 keV ions) with sign opposite than pitch and inside narrow bands than the 0-Resonance. In this case a loss of peripherical passing particles appears, placed also along the more positive potential band side. The other Resonances (except the -4) have much less effect on particle trapping and confinement. All these phenomena have been explained by the action of magnetic barriers and different mechanisms for particle orbit modification. (Author) 8 refs

  13. Effect of Surface Hydrogen Coverage on Field Emission Properties of DiamondFilms Investigated by High-Resolution Electron Energy Loss Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Guang; XIONG Yan-Yun; LIN Zhang-Da; FENG Ke-An; GU Chang-Zhi; JIN Zeng-Sun

    2000-01-01

    The influence of surface hydrogen coverage on the electron field emission of diamond films was investigated by high-resolution electron energy loss spectroscopy. It was found that hydrogen plasma treatment increased the surface hydrogen coverage while annealing caused hydrogen desorption and induced surface reconstruction. Field electron emission measurements manifested that increase of surface hydrogen coverage could improve the field emission properties, due to the decrease of electron affinity of the diamond .surface hy hvdrogen adsorption.

  14. Comunidad de mariposas diurnas (Lepidoptera:Rhopalocera en un gradiente altitudinal del cañon del rio Combeima-Tolima, Colombia Butterflies Community (Lepidoptera:Rhopalocera Along an Altitudinal Gradient in Combeima River Canyon Tolima, Colombia

    Directory of Open Access Journals (Sweden)

    Calderón C. Anderson M.

    2007-08-01

    Full Text Available Se estudió la variación altitudinal de la composición, riqueza, diversidad y estructura de la comunidad de mariposas diurnas en un gradiente altitudinal en la cuenca del río Combeima (Juntas-Tolima, Colombia, desde los 1.800 m hasta los 3.000 m a lo largo del año en tres periódos de muestreo, mediante el uso de redes entomológicas y trampas VanSomeren-Rydon. Se encontraron 101 especies de mariposas distribuidas en 59
    géneros y cinco familias cuyos parámetros poblacionales variaron espacial y temporalmente, mostrando marcada zonificación altitudinal en los 1.900 m la cual es una franja
    transicional de la composición faunística y en la que a partir de ella, existe un decremento en el número de especies exclusivas para cada estación de muestreo, las cuales
    podrían considerarse como especies indicadoras de disturbio ecosistémico.Altitudinal variations in composition, richness, diversity and structure were studied in the butterflies' communities along an altitudinal gradient in Combeima River basin (Juntas-Tolima, Colombia from 1800 m until 3000 m during one year through three sampling times, using insect nets and VanSomeren-Rydon traps. 101 butterflies species were collected that were classified into 59 genera and five families. Butterflies population values changed through altitude and year season, and showed important ecological changes in 1900 m where we found a transition zone in fauna composition and where exclusive fauna decrease in each sampling station. This exclusive fauna could be named as indicator of ecological disturbances.

  15. COMUNIDAD DE MARIPOSAS DIURNAS (LEPIDOPTERA:RHOPALOCERA EN UN GRADIENTE ALTITUDINAL DEL CAÑON DEL RÍO COMBEIMATOLIMA, COLOMBIA Butterflies Community (Lepidoptera:Rhopalocera Along an Altitudinal Gradient in Combeima River Canyon Tolima, Colombia

    Directory of Open Access Journals (Sweden)

    ÉDGAR CAMERO

    2007-11-01

    Full Text Available Se estudió la variación altitudinal de la composición, riqueza, diversidad y estructura de la comunidad de mariposas diurnas en un gradiente altitudinal en la cuenca del río Combeima (JuntasTolima, Colombia, desde los 1.800 m hasta los 3.000 m a lo largo del año en tres periódos de muestreo, mediante el uso de redes entomológicas y trampas VanSomerenRydon. Se encontraron 101 especies de mariposas distribuidas en 59 géneros y cinco familias cuyos parámetros poblacionales variaron espacial y temporalmente, mostrando marcada zonificación altitudinal en los 1.900 m la cual es una franja transicional de la composición faunística y en la que a partir de ella, existe un decremento en el número de especies exclusivas para cada estación de muestreo, las cuales podrían considerarse como especies indicadoras de disturbio ecosistémico.Altitudinal variations in composition, richness, diversity and structure were studied in the butterflies’ communities along an altitudinal gradient in Combeima River basin (JuntasTolima, Colombia from 1800 m until 3000 m during one year through three sampling times, using insect nets and VanSomerenRydon traps. 101 butterflies species were collected that were classified into 59 genera and five families. Butterflies population values changed through altitude and year season, and showed important ecological changes in 1900 m where we found a transition zone in fauna composition and where exclusive fauna decrease in each sampling station. This exclusive fauna could be named as indicator of ecological disturbances.

  16. Altitudinal ranging of black-crested gibbons at Mt. Wuliang, Yunnan: effects of food distribution, temperature and human disturbance.

    Science.gov (United States)

    Fan, Peng-Fei; Jiang, Xue-Long

    2010-01-01

    We studied the altitudinal ranging of one habituated group of black-crested gibbons (Nomascus concolor) at Dazhaizi, Mt. Wuliang, Yunnan, China, between March 2005 and April 2006. The group ranged from 1,900 to 2,680 m above sea level. Food distribution was the driving force behind the altitudinal ranging patterns of the study group. They spent 83.2% of their time ranging between 2,100 and 2,400 m, where 75.8% of important food patches occurred. They avoided using the area above 2,500 m despite a lack of human disturbance there, apparently because there were few food resources. Temperature had a limited effect on seasonal altitudinal ranging but probably explained the diel altitudinal ranging of the group, which tended to use the lower zone in the cold morning and the higher zone in the warm afternoon. Grazing goats, the main disturbance, were limited to below 2,100 m, which was defined as the high-disturbance area (HDA). Gibbons spent less time in the HDA and, when ranging there, spent more time feeding and travelling and less time resting and singing. Human activities directly influenced gibbon behaviour, might cause forest degradation and create dispersal barriers between populations.

  17. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the U

  18. Connecting the dots: a correlation between ionising radiation and cloud mass-loss rate traced by optical integral field spectroscopy

    CERN Document Server

    McLeod, A F; Dale, J E; Ginsburg, A; Klaassen, P D; Mottram, J C; Preibisch, T; Ramsay, S; Reiter, M; Testi, L

    2016-01-01

    We present an analysis of the effect of feedback from O- and B-type stars with data from the integral field spectrograph MUSE mounted on the Very Large Telescope of pillar-like structures in the Carina Nebular Complex, one of the most massive star-forming regions in the Galaxy. For the observed pillars, we compute gas electron densities and temperatures maps, produce integrated line and velocity maps of the ionised gas, study the ionisation fronts at the pillar tips, analyse the properties of the single regions, and detect two ionised jets originating from two distinct pillar tips. For each pillar tip we determine the incident ionising photon flux $Q_\\mathrm{0,pil}$ originating from the nearby massive O- and B-type stars and compute the mass-loss rate $\\dot{M}$ of the pillar tips due to photo-evaporation caused by the incident ionising radiation. We combine the results of the Carina data set with archival MUSE data of a pillar in NGC 3603 and with previously published MUSE data of the Pillars of Creation in M...

  19. Optical Dark-Field and Electron Energy Loss Imaging and Spectroscopy of Symmetry-Forbidden Modes in Loaded Nanogap Antennas.

    Science.gov (United States)

    Brintlinger, Todd; Herzing, Andrew A; Long, James P; Vurgaftman, Igor; Stroud, Rhonda; Simpkins, B S

    2015-06-23

    We have produced large numbers of hybrid metal-semiconductor nanogap antennas using a scalable electrochemical approach and systematically characterized the spectral and spatial character of their plasmonic modes with optical dark-field scattering, electron energy loss spectroscopy with principal component analysis, and full wave simulations. The coordination of these techniques reveal that these nanostructures support degenerate transverse modes which split due to substrate interactions, a longitudinal mode which scales with antenna length, and a symmetry-forbidden gap-localized transverse mode. This gap-localized transverse mode arises from mode splitting of transverse resonances supported on both antenna arms and is confined to the gap load enabling (i) delivery of substantial energy to the gap material and (ii) the possibility of tuning the antenna resonance via active modulation of the gap material's optical properties. The resonant position of this symmetry-forbidden mode is sensitive to gap size, dielectric strength of the gap material, and is highly suppressed in air-gapped structures which may explain its absence from the literature to date. Understanding the complex modal structure supported on hybrid nanosystems is necessary to enable the multifunctional components many seek.

  20. [Distribution and diversity of springtails (Hexapoda: Collembola) on the altitudinal gradient of a temperate forest in Mexico].

    Science.gov (United States)

    García-Gómez, Arturo; Castaño-Meneses, Gabriela; Palacios-Vargas, José G

    2011-03-01

    Mountain ecosystems have shown slow mineralization activity due to weather conditions, and to some groups with arthropods with special roles. The Collembola is an important group for litter fragmentation, showing different distribution patterns. The objective of the present study was to determine the diversity of Collembola along a volcano altitudinal gradient. For this, four sampling expeditions evaluated four altitudinal levels (I = 2 753, II = 3 015, III = 3 250 and IV = 3 687 masl) in Iztaccihuatl Volcano, from November 2003, and March, June and August 2004. Shannon diversity (H'), Pielou evenness (J') and Simpson dominance (1/lambda) indices were calculated. The similarity between the associations of springtails between the sampling sites was evaluated by a cluster analysis using the Pearson correlation coefficient, as distance and the unpaired arithmetic averages (UPGMA) as amalgamation method. A total of 24 075 springtails, distributed in 12 families, 46 genera and 86 species was collected. The higher species abundance was found at the altitudinal area II. The lowest diversity value was recorded in IV, while the higher diversity values were found in III. Significant differences between Shannon indices were found between zones II-III (t(0.01, 187) = 4.11, p springtail abundances was not found, but it was observed that, the lower altitude (I) resulted more homogeneous along the studied period, followed by level II and III. There is a particular assemblage of springtails community in each altitudinal area studied; in general, the sites with low slope resulted more diverse in Collembola communities. These results show that there are important factors such as altitude, vegetation type and microhabitat heterogeneity that may affect the distribution of springtails communities along an altitudinal gradient. PMID:21516653

  1. Intra- and interspecific tree growth across a long altitudinal gradient in the Peruvian Andes.

    Science.gov (United States)

    Rapp, Joshua M; Silman, Miles R; Clark, James S; Girardin, Cecile A J; Galiano, Darcy; Tito, Richard

    2012-09-01

    Tree growth response across environmental gradients is fundamental to understanding species distributional ecology and forest ecosystem ecology and to predict future ecosystem services. Cross-sectional patterns of ecosystem properties with respect to climatic gradients are often used to predict ecosystem responses to global change. Across sites in the tropics, primary productivity increases with temperature, suggesting that forest ecosystems will become more productive as temperature rises. However, this trend is confounded with a shift in species composition and so may not reflect the response of in situ forests to warming. In this study, we simultaneously studied tree diameter growth across the altitudinal ranges of species within a single genus across a geographically compact temperature gradient, to separate the direct effect of temperature on tree growth from that of species compositional turnover. Using a Bayesian state space modeling framework we combined data from repeated diameter censuses and dendrometer measurements from across a 1700-m altitudinal gradient collected over six years on over 2400 trees in Weinmannia, a dominant and widespread genus of cloud forest trees in the Andes. Within species, growth showed no consistent trend with altitude, but higher-elevation species had lower growth rates than lower-elevation species, suggesting that species turnover is largely responsible for the positive correlation between productivity and temperature in tropical forests. Our results may indicate a significant difference in how low- and high-latitude forests will respond to climate change, since temperate and boreal tree species are consistently observed to have a positive relationship between growth and temperature. If our results hold for other tropical species, a positive response in ecosystem productivity to increasing temperatures in the Andes will depend on the altitudinal migration of tree species. The rapid pace of climate change, and slow observed

  2. Charge losses in silicon sensors and electric-field studies at the Si-SiO{sub 2} interface

    Energy Technology Data Exchange (ETDEWEB)

    Poehlsen, Thomas

    2013-07-15

    Electric fields and charge losses in silicon sensors before and after irradiation with x-rays, protons, neutrons or mixed irradiation are studied in charge-collection measurements. Electron-hole pairs (eh pairs) are generated at different positions in the sensor using sub-ns pulsed laser light of different wavelengths. Light of 1063 nm, 830 nm and 660 nm wavelength is used to generate eh pairs along the whole sensor depth, a few {mu}m below the surface and very close to the surface, respectively. Segmented p{sup +}n silicon strip sensors are used to study the electric field below the SiO{sub 2} separating the strip implants. The sensors are investigated before and after irradiation with 12 keV X-rays to a dose of 1 MGy. It is found that the electric field close to the Si-SiO{sub 2} interface depends on both the irradiation dose and the biasing history. For the non-irradiated sensors the observed dependence of the electric field on biasing history and humidity is qualitatively as expected from simulations of the electrostatic potential for different boundary conditions at the surface. Depending on the biasing history incomplete collection of electrons, full charge collection or incomplete collection of holes is observed. After the bias voltage is changed, the amount of observed charge losses is time dependent with time constants being a function of humidity. For the irradiated sensors an increased effective oxide charge density and more electron losses are observed compared to the non-irradiated sensors. Due to positive oxide charges which are always present at the Si-SiO{sub 2} interface an electronaccumulation layer forms, if the oxide charge is not compensated by charges on top of the passivation. If negative charges overcompensate the oxide charge, a hole-accumulation layer forms. In both cases the number of accumulated charges can be temporarily increased by incomplete charge collection of either electrons or holes. How many additional charge carriers can be

  3. Possible altitudinal, latitudinal and directional dependence of relativistic Sagnac effect in Chern-Simons modified gravity

    CERN Document Server

    Kikuchi, Daiki; Yamada, Kei; Asada, Hideki

    2014-01-01

    Toward a test of parity violation in a gravity theory, possible effects of Chern-Simons (CS) gravity on an interferometer have been recently discussed. Continuing work initiated in an earlier publication [Okawara, Yamada and Asada, Phys. Rev. Lett. 109, 231101 (2012)], we study possible altitudinal and directional dependence of relativistic Sagnac effect in CS modified gravity. We compare the CS effects on Sagnac interferometers with the general relativistic Lense-Thirring (LT) effects. Numerical calculations show that the eastbound Sagnac interferometer might be preferred for testing CS separately, because LT effects on this interferometer cancel out. The size of the phase shift induced in the CS model might have an oscillatory dependence also on the altitude of the interferometer through the CS mass parameter $m_{CS}$. Therefore, the international space station site as well as a ground-based experiment is also discussed.

  4. Altitudinal changes in diversity of macroinvertebrates from small streams in the Ecuadorian Andes

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2003-01-01

    Altitudinal patterns in diversity of macroinvertebrate families at different spatial scales (stone, stream and altitude) were studied by collecting stone samples from six streams at each of the three altitudes: lowlands (400m), midlands (2000m) and highlands (3800 m), in the equatorial Andes...... was dominated by insects, mainly Ephemeroptera, Trichoptera and Diptera at all three altitudes. Odonata and Hemiptera were relatively rich in lowland streams, scarcely present in the midland streams and absent in the highland streams (as was the case for the less diverse orders Lepidoptera and Megaloptera....... In contrast, beta diversity (taxon turnover among streams) increased with altitude. The higher richness in the lowland streams appeared at the smallest spatial scale (stone), and was therefore not due to higher beta diversity among stones within streams. Local richness was nearly linearly related to regional...

  5. Investigation of electric fields, losses and depolarization of ultra-cold neutrons for the new nEDM experiment at FRM II

    OpenAIRE

    Chesnevskaya, Svetlana

    2015-01-01

    This work has shown that the electric field can be produced using different conductive plastics for a high-voltage electrode. Simulations of the electric field and systematic effects result in false effects one or two orders below the statistical uncertainties. Using glass and aluminum as neutron guides and different wall coatings for them, ultra-cold neutron losses and depolarization can be kept below the critical value to allow a measurement goal of 5·10-28 e·cm.

  6. Effect of desmopressin administration on intraoperative blood loss and quality of the surgical field during functional endoscopic sinus surgery: a randomized, clinical trial

    OpenAIRE

    Shao, Hua; Kuang, Li-Ting; Hou, Wei-Jian; Zhang,Tao

    2015-01-01

    Background Bleeding during functional endoscopic sinus surgery is a challenge for the quality of the surgical field for surgeons. This study aimed to evaluate the effect of desmopressin premedication on blood loss and the quality of the surgical field in endoscopic sinus surgery. Methods A total of 90 American Society of Anesthesiologists physical status I–II patients underwent endoscopic sinus surgery for chronic sinusitis. They were randomly allocated to receive either desmopressin 0.3 μg/k...

  7. Litterfall production along successional and altitudinal gradients of subtropical monsoon evergreen broadleaved forests in Guangdong, China

    Science.gov (United States)

    Zhou, G.; Guan, L.; Wei, X.; Zhang, Dongxiao; Zhang, Q.; Yan, J.; Wen, D.; Liu, J.; Liu, S.; Huang, Z.; Kong, G.; Mo, J.; Yu, Q.

    2007-01-01

    Evaluation of litterfall production is important for understanding nutrient cycling, forest growth, successional pathways, and interactions with environmental variables in forest ecosystems. Litterfall was intensively studied during the period of 1982-2001 in two subtropical monsoon vegetation gradients in the Dinghushan Biosphere Reserve, Guangdong Province, China. The two gradients include: (1) a successional gradient composed of pine forest (PF), mixed pine and broadleaved forest (MF) and monsoon evergreen broadleaved forest (BF), and (2) an altitudinal gradient composed of Baiyunci ravine rain forest (BRF), Qingyunci ravine rain forest (QRF), BF and mountainous evergreen broadleaved forest (MMF). Mean annual litterfall production was 356, 861 and 849 g m-2 for PF, MF and BF of the successional gradient, and 1016, 1061, 849 and 489 g m-2 for BRF, QRF, BF and MMF of the altitudinal gradient, respectively. As expected, mean annual litterfall of the pioneer forest PF was the lowest, but rapidly increased over the observation period while those in other forests were relatively stable, confirming that forest litterfall production is closely related to successional stages and growth patterns. Leaf proportions of total litterfall in PF, MF, BF, BRF, QRF and MMF were 76.4%, 68.4%, 56.8%, 55.7%, 57.6% and 69.2%, respectively, which were consistent with the results from studies in other evergreen broadleaved forests. Our analysis on litterfall monthly distributions indicated that litterfall production was much higher during the period of April to September compared to other months for all studied forest types. Although there were significant impacts of some climate variables (maximum and effective temperatures) on litterfall production in some of the studied forests, the mechanisms of how climate factors (temperature and rainfall) interactively affect litterfall await further study. ?? 2006 Springer Science+Business Media B.V.

  8. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kajikawa, K., E-mail: kajikawa@sc.kyushu-u.ac.j [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Funaki, K. [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Shikimachi, K.; Hirano, N.; Nagaya, S. [Chubu Electric Power Co., Inc., 20-1 Kitasekiyama, Ohdaka-cho, Midori-ku, Nagoya 459-8522 (Japan)

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  9. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Science.gov (United States)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  10. Structural and functional changes in Nothofagus pumilio forests along an altitudinal gradient in Tierra del Fuego, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M.D.; Frangi, J.L.; Perdomo, M.H. [Univ. Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Richter, L.L.; Pinedo, L.B. [CADIC, Ushuaia (Argentina)

    2000-04-01

    Structural (density, height, basal area, above-ground tree biomass, leaf area index) and functional (leaf phenology, growth rate, fine litter fall, leaf decomposition) traits were quantified in four mature forests of Notofagus pumilio (lenga) along an altitudinal sequence in Tierra del Fuego, Argentina. Three erect forest stands at 220, 440 and 540 m and a krummholz stand at 640 m a.s.l. were selected. Along the altitudinal sequence, stem density increased while DBH, height, biomass, leaf-size and growth period, mean growth rate and decay rate decreased. Dead stems increased and basal area and fine-litter fall decreased with an increase in elevation among erect forests, but these trends inverted at krummholz. We suggest that krummholz is not only a morphological response to the adverse climate but is also a life form with functional advantages.

  11. Differences between tree species seedling and adult altitudinal distribution in mountain foests during the recent warm period (1986-2006)

    DEFF Research Database (Denmark)

    Lenoir, Jonathan; Gégout, Jean-Claude; Pierrat, Jean-Claude;

    2009-01-01

    distribution across the overall temperature gradient remains poorly explored. Within French mountain forests, we investigated altitudinal distribution differences between seedling (≤50 cm tall and >1 yr old) and adult (>8 m tall) life stages for 17 European tree taxa, encompassing the entire forest elevation......Spatial fingerprints of climate change on tree species distribution are usually detected at latitudinal or altitudinal extremes (arctic or alpine tree line), where temperatures play a key role in tree species distribution. However, early detection of recent climate change effects on tree species...... range from lowlands to the subalpine vegetation belt (50-2250 m a.s.l.) and spanning the latitudinal gradient from northern temperate to southern Mediterranean forests. We simultaneously identified seedlings and adults within the same vegetation plots. These twin observations gave us the equivalent...

  12. Genetic structure of sigmodontine rodents (Cricetidae) along an altitudinal gradient of the Atlantic Rain Forest in southern Brazil

    OpenAIRE

    Gonçalves, Gislene L.; Marinho, Jorge R.; de Freitas, Thales R. O.

    2009-01-01

    The population genetic structure of two sympatric species of sigmodontine rodents (Oligoryzomys nigripes and Euryoryzomys russatus) was examined for mitochondrial DNA (mtDNA) sequence haplotypes of the control region. Samples were taken from three localities in the Atlantic Rain Forest in southern Brazil, along an altitudinal gradient with different types of habitat. In both species there was no genetic structure throughout their distribution, although levels of genetic variability and gene f...

  13. Genetic structure of sigmodontine rodents (Cricetidae) along an altitudinal gradient of the Atlantic Rain Forest in southern Brazil.

    Science.gov (United States)

    Gonçalves, Gislene L; Marinho, Jorge R; Freitas, Thales R O

    2009-10-01

    The population genetic structure of two sympatric species of sigmodontine rodents (Oligoryzomys nigripes and Euryoryzomys russatus) was examined for mitochondrial DNA (mtDNA) sequence haplotypes of the control region. Samples were taken from three localities in the Atlantic Rain Forest in southern Brazil, along an altitudinal gradient with different types of habitat. In both species there was no genetic structure throughout their distribution, although levels of genetic variability and gene flow were high. PMID:21637469

  14. Genetic structure of sigmodontine rodents (Cricetidae along an altitudinal gradient of the Atlantic Rain Forest in southern Brazil

    Directory of Open Access Journals (Sweden)

    Gislene L. Gonçalves

    2009-01-01

    Full Text Available The population genetic structure of two sympatric species of sigmodontine rodents (Oligoryzomys nigripes and Euryoryzomys russatus was examined for mitochondrial DNA (mtDNA sequence haplotypes of the control region. Samples were taken from three localities in the Atlantic Rain Forest in southern Brazil, along an altitudinal gradient with different types of habitat. In both species there was no genetic structure throughout their distribution, although levels of genetic variability and gene flow were high.

  15. Relationship between the Retinal Nerve Fibre Layer (RNFL parameters and Visual field loss in established glaucoma patients in South Indian population

    Directory of Open Access Journals (Sweden)

    Elangovan Suma, Puri K Sanjeev

    2013-10-01

    Full Text Available Purpose: Optical coherence tomography (OCT and Scanning LASER polarimetry (GDX-VCC are newer techniques to analyse retinal nerve fibre loss in glaucoma. This study aims to evaluate the relationship between the Retinal Nerve Fibre Layer(RNFL parameters measured using Stratus-OCT and GDx-VCC and visual field loss by Octopus interzeag perimetry in established glaucoma patients in South Indian Population. Materials and methods: Prospectively planned cross sectional study of 67 eyes of 34 established glaucoma patients on medical management. The mean age of patients was 46.911 years (SD+13.531. A complete ophthalmic examination, automated perimetry with octopus interzeag 1-2-3 perimeter, retinal nerve fibre analysis with GDx VCC and Stratus OCT was done. The differences between the mean RNFL parameters in the presence or absence of field defects were evaluated. Results: The data analysed were mean deviation, loss variance, OCT total average nerve fibre thickness, GDX VCC- TSNIT average and Nerve fibre indicator (NFI.The data were split into two subgroups on the basis of presence or absence of visual field defect and analysed. The difference between the mean value of NFI between the subgroups was highly significant with a p value < 0.01.The OCT parameter Total average nerve fiber layer thickness differed significantly between the two subgroups (p value <0.05. The mean GDx TSNIT average did not differ significantly between the two subgroups. Conclusion: The total average nerve fibre thickness by OCT correlated better with visual field loss than the GDX TSNIT average .Among the GDx parameters, the NFI was found to be a better indicator of visual field damage than the average thickness.

  16. An Invariant Allometric Scaling of Nitrogen and Phosphorus in Leaves, Stems and Fine roots Along an Altitudinal Gradient

    Science.gov (United States)

    Zhao, Ning; He, Nianpeng; Wang, Qiufeng; Wang, Ruili; Xu, Zhiwei; YU, Guirui

    2014-05-01

    Plant nutrient allocation explicitly links the plant resource capture strategy to the material and energy cycles of ecosystems. The nitrogen (N) to phosphorus (P) relationship in plant organs is of particular interest, as N and P are the major limiting elements for plant growth. Here we analyze the relations of N and P in leaves, stems and fine roots of 269 species along an altitudinal transect on the northern slope of Changbai Mountain, China, to explore the partitioning of nutrients in major plant organs and its response to environmental gradient. We find that N, P contents as well as N: P ratio are significantly higher in leaves than in stems and fine roots. Nutrient contents of major plant organs show consistent response to the altitudinal gradient. N and P contents of leaves, stems and fine roots increased while N:P ratios decreased with elevation. Moreover, general allometric scaling relations of N and P is found in leaves, stems and fine roots with slopes of 0.78, 0.72 and 0.87, respectively, and differences exist among different plant growth forms. In general, the exponent values of the allometric scaling of N and P in leaves, stems and fine roots keep as an invariant constant along the altitudinal gradient, which implies the existence of conserved nutrient allocation strategies in plant.

  17. Exploring climatic controls on blanket bog litter decomposition across an altitudinal gradient

    Science.gov (United States)

    Bell, Michael; Ritson, Jonathan P.; Clark, Joanna M.; Verhoef, Anne; Brazier, Richard E.

    2016-04-01

    The hydrological and ecological functioning of blanket bogs is strongly coupled, involving multiple ecohydrological feedbacks which can affect carbon cycling. Cool and wet conditions inhibit decomposition, and favour the growth of Sphagnum mosses which produce highly recalcitrant litter. A small but persistent imbalance between production and decomposition has led to blanket bogs in the UK accumulating large amounts of carbon. Additionally, healthy bogs provide a suite of other ecosystems services including water regulation and drinking water provision. However, there is concern that climate change could increase rates of litter decomposition and disrupt this carbon sink. Furthermore, it has been argued that the response of these ecosystems in the warmer south west and west of the UK may provide an early analogue for later changes in the more extensive northern peatlands. In order to investigate the effects of climate change on blanket bog litter decomposition, we set-up a litter bag experiment across an altitudinal gradient spanning 200 m of elevation (including a transition from moorland to healthy blanket bog) on Dartmoor, an area of hitherto unstudied, climatically marginal blanket bog in the south west of the UK. At seven sites, water table depth and soil and surface temperature were recorded continuously. Litter bags filled with the litter of three vegetation species dominant on Dartmoor were incubated just below the bog surface and retrieved over a period of 12 months. We found significant differences in the rate of decomposition between species. At all sites, decomposition progressed in the order Calluna vulgaris (dwarf shrub) > Molinia caerulea (graminoid) > Sphagnum (bryophyte). However, while soil temperature did decrease along the altitudinal gradient, being warmer in the lower altitudes, a hypothesised accompanying decrease in decomposition rates did not occur. This could be explained by greater N deposition at the higher elevation sites (estimated

  18. Relationship between visual field sensitivity loss and quadrantic macular thickness measured with Stratus-Optical coherence tomography in patients with chiasmal syndrome

    OpenAIRE

    Frederico Castelo Moura; Luciana Virginia Ferreira Costa-Cunha; Roberto Freire Santiago Malta; Mário Luiz Ribeiro Monteiro

    2010-01-01

    PURPOSE: To correlate visual field sensitivity (VFS) loss on standard automated perimetry (SAP) and quadrantic macular thickness on optical coherence tomography (OCT) in patients with permanent temporal hemianopia from chiasmal compression. METHODS: Forty eyes from 40 patients with chiasmal compression and 40 healthy eyes were submitted to standard automated perimetry and Stratus-OCT scanning. Raw data of the fast macular thickness scanning protocol were exported and macular thickness measure...

  19. Evaluating the risk of non-point source pollution from biosolids: integrated modelling of nutrient losses at field and catchment scales

    OpenAIRE

    P. G. Whitehead; Heathwaite, A. L.; N. J. Flynn; Wade, A. J.; Quinn, P. F.

    2007-01-01

    International audience A semi-distributed model, INCA, has been developed to determine the fate and distribution of nutrients in terrestrial and aquatic systems. The model simulates nitrogen and phosphorus processes in soils, groundwaters and river systems and can be applied in a semi-distributed manner at a range of scales. In this study, the model has been applied at field to sub-catchment to whole catchment scale to evaluate the behaviour of biosolid-derived losses of P in agricultural ...

  20. Changes in structure and composition of evergreen forests on an altitudinal gradient in the Venezuelan Guayana shield.

    Science.gov (United States)

    Hernández, Lionel; Dezzeo, Nelda; Sanoja, Elio; Salazar, Leandro; Castellanos, Hernán

    2012-03-01

    There have been several ecological studies in forests of the Guayana Shield, but so far none had examined the changes in structure and composition of evergreen forests with altitude. This study describes and analyzes the structure, species composition and soil characteristics of forest stands at different altitudinal zones in Southeastern Venezuelan Guayana, in order to explain the patterns and the main factors that determine the structure and composition of evergreen forests along the altitudinal gradient. Inventories of 3 948 big (>10cm DBH) and 1 328 small (5-10cm DBH) woody stems were carried out in eleven plots, ranging from 0.1 to 1.0ha, along a 188km long transect with elevations between 290 and 1 395masl. It has been found that 1) hemiepihytes become more dominant and lianas reduce their dominance with increasing altitude and 2) the forest structure in the study area is size-dependent. Five families and 12 genera represented only 9% of the total number of families and genera, respectively, recorded troughout the gradient, but the two groups of taxa comprised more than 50% of the Importance Value (the sum of the relative density and the relative dominance) of all measured stems. Moreover, the results suggest that low species richness seems to be associated with the dominance of one or few species. Stand-level wood density (WD) of trees decreased significantly with increasing elevation. WD is an indicator of trees'life history strategy. Its decline suggests a change in the functional composition of the forest with increasing altitude. The Canonical Correspondence Analysis (CCA) indicated a distinction of the studied forests on the basis of their altitudinal levels and geographic location, and revealed different ecological responses by the forests, to environmental variables along the altitudinal gradient. The variation in species composition, in terms of basal area among stands, was controlled primarily by elevation and secondarily by rainfall and soil

  1. Relationship between visual field sensitivity loss and quadrantic macular thickness measured with Stratus-Optical coherence tomography in patients with chiasmal syndrome

    Directory of Open Access Journals (Sweden)

    Frederico Castelo Moura

    2010-10-01

    Full Text Available PURPOSE: To correlate visual field sensitivity (VFS loss on standard automated perimetry (SAP and quadrantic macular thickness on optical coherence tomography (OCT in patients with permanent temporal hemianopia from chiasmal compression. METHODS: Forty eyes from 40 patients with chiasmal compression and 40 healthy eyes were submitted to standard automated perimetry and Stratus-OCT scanning. Raw data of the fast macular thickness scanning protocol were exported and macular thickness measurements were recorded and averaged for each quadrant and half of the central area. The correlation between visual field sensitivity loss and optical coherence tomography measurements was tested with Pearson's correlation coefficients and with linear regression analysis. RESULTS: A significant association was found between each macular thickness parameter and the corresponding central VF mean sensitivity. The strongest association was observed between superonasal macular thickness and the inferotemporal mean defect measured both in decibel (R=0.47; p=0.001 and in 1/Lambert (R=0.59; p<0.0001 units. CONCLUSION: Stratus-OCT-measured macular thickness was topographically related with visual field sensitivity loss in patients with temporal hemianopia from chiasmal compression. Such measurements could prove clinically useful in the diagnosis and follow-up of patients with chiasmal compression. ClinicalTrial.gov identifier number: NCT0039122.

  2. Low power loss and field-insensitive permeability of Fe-6.5%Si powder cores with manganese oxide-coated particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junnan, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Wang, Xian; Xu, Xiaojun; Gong, Rongzhou, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Feng, Zekun [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Yajie; Harris, V. G. [Department of Electrical and Computer Engineering, Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States)

    2015-05-07

    Fe-6.5%Si alloy powders coated with manganese oxides using an innovative in situ process were investigated. The in-situ coating of the insulating oxides was realized with a KMnO{sub 4} solution by a chemical process. The insulating manganese oxides with mixed valance state were verified by X-ray photoelectron spectroscopy analysis. The thickness of the insulating layer on alloy particles was determined to be in a range of 20–210 nm, depending upon the KMnO{sub 4} concentration. The powder core loss and the change in permeability under a DC-bias field were measured at frequencies ranging from 50 to 100 kHz. The experiments indicated that the Fe-6.5%Si powder cores with a 210 nm-thick manganese oxide layer not only showed a low core loss of 459 mW/cm{sup 3} at 100 kHz but also showed a small reduction in permeability (μ(H)/μ(0) = 85% for μ = 42) at a DC-bias field of 80 Oe. This work has defined a novel pathway to realizing low core loss and field-insensitive permeability for Fe-Si powder cores.

  3. Comparison of fractal characteristics of species richness patterns among different plant taxonomic groups along an altitudinal gradient

    Institute of Scientific and Technical Information of China (English)

    REN Haibao; ZHANG Linyan; MA Keping

    2007-01-01

    This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees,shrubs,herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations.Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing,China.Both transects were continuous and 2 m wide,and every individual tree and shrub was recorded in each of them.Discrete quadrats of 1m × 1m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients.The level interval between the quadrats was 10m and 25m respectively.In this study,transects A and B were combined into one transect AB,and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns.Species richness in each quadrat was calculated using a program written in Matlab 6.0.Direct gradient analysis was used to describe the overall trends in the species richness of trees,shrubs,herbs and other plants with change in altitude,while the non-brown ffactal model was used to detect more accurately their variations at various scales along the gradient.The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function.Generally,ecological phenomena are determined not by a single ecological process but by multiple ones.These processes act on ecological patterns within their own spatial scales.In the non-brown fractal model,the spatial random functions are nested within a larger range of spatial scales.The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero.In this paper,we reached the following results and conclusions

  4. Seasonal changes in the altitudinal distribution of nocturnally migrating birds during autumn migration

    Science.gov (United States)

    La Sorte, Frank A.; Hochachka, Wesley M.; Farnsworth, Andrew; Sheldon, Daniel; Van Doren, Benjamin M.; Fink, Daniel; Kelling, Steve

    2015-01-01

    Wind plays a significant role in the flight altitudes selected by nocturnally migrating birds. At mid-latitudes in the Northern Hemisphere, atmospheric conditions are dictated by the polar-front jet stream, whose amplitude increases in the autumn. One consequence for migratory birds is that the region’s prevailing westerly winds become progressively stronger at higher migration altitudes. We expect this seasonality in wind speed to result in migrants occupying progressively lower flight altitudes, which we test using density estimates of nocturnal migrants at 100 m altitudinal intervals from 12 weather surveillance radar stations located in the northeastern USA. Contrary to our expectations, median migration altitudes deviated little across the season, and the variance was lower during the middle of the season and higher during the beginning and especially the end of the season. Early-season migrants included small- to intermediate-sized long-distance migrants in the orders Charadriiformes and Passeriformes, and late-season migrants included large-bodied and intermediate-distance migrants in the order Anseriformes. Therefore, seasonality in the composition of migratory species, and related variation in migration strategies and behaviours, resulted in a convex–concave bounded distribution of migration altitudes. Our results provide a basis for assessing the implications for migratory bird populations of changes in mid-latitude atmospheric conditions probably occurring under global climate change. PMID:27019724

  5. Methane-cycling microorganisms in soils of a high-alpine altitudinal gradient.

    Science.gov (United States)

    Hofmann, Katrin; Pauli, Harald; Praeg, Nadine; Wagner, Andreas O; Illmer, Paul

    2016-03-01

    Methanogens and methanotrophs play unique roles as producers and consumers of the greenhouse gas methane (CH4) in soils, respectively. Here, we aimed to reveal whether and to which extent methane-cyclers occur in high-alpine soils, and to assess their spatial distribution along an altitudinal gradient (2700-3500 m) in the Austrian Alps at sites located within the alpine (2700-2900 m), the alpine-nival (3000-3100 m) and the nival belts (3200-3500 m). Methanococcales and Methanocella spp. were most abundant among all quantified methanogenic guilds, whereas Methanosarcinales were not detected in the studied soil. The detected methanogens seem to be capable of persisting despite a highly oxic low-temperature environment. Methanogenic and methanotrophic activities and abundances of methanotrophs, Methanococcales and Methanocella spp. declined with altitude. Methanogenic and methanotrophic abundances were best explained by mean annual soil temperature and dissolved organic carbon, respectively. Alpine belt soils harbored significantly more methane-cyclers than those of the nival belt, indicating some influence of plant cover. Our results show that methanogens are capable of persisting in high-alpine cold soils and might help to understand future changes of these environments caused by climate warming. PMID:26790465

  6. Altitudinal variation of secondary metabolite profiles in flowering heads of Arnica montana cv. ARBO.

    Science.gov (United States)

    Spitaler, Renate; Schlorhaufer, P Daniel; Ellmerer, Ernst P; Merfort, Irmgard; Bortenschlager, Sigmar; Stuppner, Hermann; Zidorn, Christian

    2006-02-01

    The altitudinal variation on the contents of secondary metabolites in flowering heads of Arnica montana was assessed. Plants of A. montana cultivar ARBO were grown in nine experimental plots at altitudes between 590 and 2230m at Mount Patscherkofel near Innsbruck/Austria. The total contents of sesquiterpene lactones and flavonoids were not positively correlated with the altitude of the growing site. However, the proportion of flavonoids with vicinal free hydroxy groups in ring B to flavonoids lacking this feature significantly increased with elevation. Additionally, the level of caffeic acid derivatives also positively correlated with the altitude of the growing site. In particular amounts of 1-methoxyoxaloyl-3,5-dicaffeoylquinic acid significantly increased in higher sites and samples from the summit region contained 85% more of this compound than samples from valley sites. These results are discussed with regards to chemosystematic studies comparing samples collected in different altitudes as well as in the light of a UV-B protective and radical scavenging function of phenolics and their significance for plant life in environments with elevated UV-B radiation.

  7. Altitudinal Variation in Digestive Tract Length in Yunnan Pond Frog (Pelophylax pleuraden)

    Institute of Scientific and Technical Information of China (English)

    Shangling LOU; Yanhong LI; Long JIN; Zhiping MI; Wenchao LIU; Wenbo LIAO

    2013-01-01

    The digestive tract plays an important role in digestion and the acquisition of food energy. Understanding the impact of abiotic environments on digestive tract morphology is especially important for evolution of digestive tract across different environments. Here, we investigated altitudinal variation in digestive tract length in the Yunnan Pond Frog (Pelophylax pleuraden) across ifve populations ranging from 1413 m to 1935 m a.s.l. in Ningnan County, Sichuan province in western China. Frogs were collected during the breeding season, from 1-5 June 2012. Our results revealed that females had longer digestive tract and relative digestive tract (i.e. digestive tract length/body size) lengths in com-parison to males, on average, but the differences between them decreased with increasing altitude. Digestive tract and relative digestive tract lengths increased with increasing altitude suggesting that a higher proportion of indigestible ma-terials may be consumed at high-altitude sites and result in a relative increase in digestive tract dimensions.

  8. Greenhouse gas emissions and N turnover along an altitudinal gradient at Mt. Kilimanjaro, Tanzania.

    Science.gov (United States)

    Gütlein, Adrian; Gerschlauer, Friederike; Zistl-Schlingmann, Marcus; Dannenmann, Michael; Meier, Rudolf; Kolar, Alison; Butterbach-Bahl, Klaus; Kiese, Ralf

    2016-04-01

    Worldwide climate and land-use change force alterations in various ecosystem properties and functions such as diversity and activity of soil microbial communities which are responsible for biogeochemical processes like soil nitrogen (N) turnover and associated greenhouse gas (GHG) exchange. Tropical deforestation is highest in Africa and despite the importance of those ecosystems to global climate and biogeochemical cycles, data for greenhouse gas exchange is still rare (Serca et al., 1994, Werner et al., 2007) and no study regarding N turnover processes has been published yet. For that reason, we focused on seven different land-use types extending along an altitudinal gradient (950 -- 3880m) at Mt. Kilimanjaro, East Africa, covering (semi-) natural savanna, two montane forests and one afro alpine ecosystem, an extensive agroforest (homegarden) and an intensively managed coffee plantation. On all ecosystems we measured CO_2, CH4 and N_2O fluxes and gross rates of ammonification, nitrification, N immobilization, and dissimilatory nitrate reduction to ammonium (DNRA). GHG results reveal pronounced N_2O fluxes depending mainly on soil moisture and to a lesser extent on soil temperature. Emissions are highest during the rainy seasons while lowest at dry season conditions. The largest N_2O emissions are recognizable at Ocotea forest, most likely due to the generally higher SOC/ totN and wetter conditions favoring formation and emission of N_2O via denitrification. Soils of the studied ecosystems were a sink of atmospheric CH

  9. Genome size variation in wild and cultivated maize along altitudinal gradients

    Science.gov (United States)

    Díez, Concepción M.; Gaut, Brandon S.; Meca, Esteban; Scheinvar, Enrique; Montes-Hernandez, Salvador; Eguiarte, Luis E.; Tenaillon, Maud I.

    2014-01-01

    Summary • It is still an open question as to whether genome size (GS) variation is shaped by natural selection. One approach to address this question is a population-level survey that assesses both the variation in GS and the relationship of GS to ecological variants. • We assessed GS in Zea mays, a species that includes the cultivated crop, maize, and its closest wild relatives, the teosintes. We measured GS in five plants of each of 22 maize landraces and 21 teosinte populations from Mexico sampled from parallel altitudinal gradients. • GS was significantly smaller in landraces than in teosintes, but the largest component of GS variation was among landraces and among populations. In maize, GS correlated negatively with altitude; more generally, the best GS predictors were linked to geography. By contrast, GS variation in teosintes was best explained by temperature and precipitation. • Overall, our results further document the size flexibility of the Zea genome, but also point to a drastic shift in patterns of GS variation since domestication. We argue that such patterns may reflect the indirect action of selection on GS, through a multiplicity of phenotypes and life-history traits. PMID:23550586

  10. ASSESSMENT OF ANTIMICROBIAL AND PHYTOCHEMICAL POTENTIALS OF HIGH ALTITUDINAL NEPALESE LICHENS

    Directory of Open Access Journals (Sweden)

    Bijaya Laxmi Maharjan

    2011-10-01

    Full Text Available Lichens and lichen products have been used in traditional medicines for centuries. The lichens of the high altitudinal meadow of MCA (Manaslu Conservation Area have remained unexplored for which this research has been conducted with an aim of unveiling the phytochemical and antimicrobial properties of lichens present there. Four densely populated lichen species namely Usnea longifolia, Setraria spp, Parmotrema reticulatum and Evernastrium nepalense were chosen for the study. The extracts of these species were obtained in 6 different solvents viz. hexane, chloroform, ethyl acetate, acetone, methanol and water by soxhlet extraction method and the antimicrobial assay was carried out by agar well diffusion method. The extract yield varied from 0.07 -29.4%. The extracts obtained showed the presence of volatile oil, saponins, coumarins and quinines, flavonic glycosides and carotenoids. The ethyl acetate fraction of E. nepalense and U. longifolia were found to be most effective against all the 8 clinical bacterial pathogens and 5 phytopathogenic fungi tested. The extracts of Cetraria spp and P. milghenensis were found to be specifically inhibiting the fungal pathogens compared to the bacterial pathogens. Generally the lichen extracts tested demonstrated antimicrobial effect which suggests a possibility of their use in treatment of various diseases caused by these and similar microorganisms.

  11. Biomass and diversity of dry alpine plant communities along altitudinal gradients in the Himalayas

    Science.gov (United States)

    Namgail, T.; Rawat, G.S.; Mishra, C.; van Wieren, S.E.; Prins, H.H.T.

    2012-01-01

    A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood. We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western Himalaya. We used generalized linear and generalized additive models to assess the relationship between these vegetation parameters and altitude. We found a hump-shaped relationship between aboveground phytomass and altitude. We suspect that this is engendered by low rainfall and trampling/excessive grazing at lower slopes by domestic livestock, and low temperature and low nutrient levels at higher slopes. We also found a unimodal relationship between plant species-richness and altitude at a single mountain as well as at the scale of entire Ladakh. The species-richness at the single mountain peaked between 5,000 and 5,200 m, while it peaked between 3,500 and 4,000 m at entire Ladakh level. Perhaps biotic factors such as grazing and precipitation are, respectively, important in generating this pattern at the single mountain and entire Ladakh. ?? 2011 The Author(s).

  12. Lead uptake and lead loss in the fresh water field crab, Barytelphusa guerini, on exposure to organic and inorganic lead

    Energy Technology Data Exchange (ETDEWEB)

    Tulasi, S.J.; Yasmeen, R.; Reddy, C.P.; Rao, J.V.R.

    1987-07-01

    Lead is a heavy metal which is widely used in paint industry, pigments, dyes, electrical components and electronics, plastic chemicals and in various other things. Since some of the lead salts are soluble in water, lead presents a potential threat to aquatic organisms. Studies dealing with invertebrates include those on mortality, growth and lead uptake in Lymnaea palustris and bioaccumulation of heavy metals in oysters and mussels. Little information exists regarding the effect of lead on the fresh water crustaceans. Hence the present investigation has been undertaken to study the uptake and loss of lead on exposure to subtoxic levels or organic and inorganic lead.

  13. Drag with external and pressure drop with internal flows: a new and unifying look at losses in the flow field based on the second law of thermodynamics

    Science.gov (United States)

    Herwig, Heinz; Schmandt, Bastian

    2013-10-01

    Internal and external flows are characterized by friction factors and drag coefficients, respectively. Their definitions are based on pressure drop and drag force and thus are very different in character. From a thermodynamics point of view in both cases dissipation occurs which can uniformly be related to the entropy generation in the flow field. Therefore we suggest to account for losses in the flow field by friction factors and drag coefficients that are based on the overall entropy generation due to the dissipation in the internal and external flow fields. This second law analysis (SLA) has been applied to internal flows in many studies already. Examples of this flow category are given together with new cases of external flows, also treated by the general SLA-approach.

  14. Damage and loss assessment on rubber trees caused by typhoon based on high-precision remote sensing data and field investigation

    Science.gov (United States)

    Li, Jian; Fang, Weihua; Tan, Chenyan

    2016-04-01

    Forest dynamics are highly relevant to land hydrology, climate, carbon budget and biodiversity. Damage and loss assessment of forest caused by typhoon is essential to the understanding of ecosystem variations. Combination of high-precision remote sensing data and field investigation is critical to the assessment of forest damage loss. In this study, high-precision remote sensing data prior to and after typhoon from IKONOS, QuickBird, unmanned aerial vehicle (UAV) are used for identifying rubber tree disturbance. The ground truth data of rubber tree damage collected through field investigation are used to verify and compare the results. Taken the forest damage induced by typhoon Rammasun (201409) in Hainan as an example, 5 damage types (overthrown, trunk snapped below 2m, trunk snapped above 2m, half-overthrown, and sheared) of rubber trees are clearly interpreted compared with field investigation results. High-precision remote sensing data is then applied to other areas to evaluate the forest damage severity. At last, rubber tree damage severity is investigated with other typhoon hazard factors such as wind, topography, soil and precipitation.

  15. Geologic and geomorphic controls of altitudinal treeline in the Canadian Rocky Mountains

    Science.gov (United States)

    Macias Fauria, M.; Johnson, E. A.

    2010-12-01

    We hypothesize that a multi-scale (in both time and space) process competition affecting topographical shelter (e.g. sites favoring snow accumulation which prevents dissecation and abrasion), and substrate and water availability, ultimately set the distribution of suitable sites where trees can establish and survive in the altitudinal treeline. Terrain characteristics on which altitudinal treelines occur are ultimately set by geological history, which determines the distribution of slope aspects, angles, and lengths, as well as the distribution, depth, transport, and texture of the regolith on which trees grow. Erosive processes (landscape evolution) create concave features where flow converges (water, avalanches, debris) - channels - and convex or planar slopes. A spatially explicit model is presented at 1m resolution which predicts tree presence on a ~ 200 km2 area in the Front Ranges of the Canadian Rocky Mountains as a function of landscape topographical variables key in water and energy balances and surface transport/instability. The model was validated with independent data from an adjacent area and successfully captures tree presence/absence. Subalpine forests form a mosaic of stand ages which is a function of the last disturbance (mostly wildfire), where the main differences from their lowland counterparts are 1) a higher portion of areas where stand dynamics are affected by disturbances linked to the presence of slopes (i.e. gravitational: avalanches, flooding/flushing events), and 2) an upslope declining frequency of sites favorable for tree establishment and survival. Thus, the presence of trees in the uppermost part of these forests largely depends on the existence of suitable conditions largely linked to topography. Such places are the result of geomorphologic processes acting on a framework set by the structural geology of the region, and thus the appearance of new sites suitable for tree growth does not depend on short (i.e. yearly to decadal) time

  16. Effect of High Receiver Thermal Loss Per Unit Area on the Performance of Solar Central Receiver Systems Having Optimum Heliostat Fields and Optimum Receiver Aperture Areas.

    Science.gov (United States)

    Pitman, Charles L.

    Recent efforts in solar central receiver research have been directed toward high temperature applications. Associated with high temperature processes are greater receiver thermal losses due to reradiation and convection. This dissertation examines the performance of central receiver systems having optimum heliostate fields and receiver aperture areas as a function of receiver thermal loss per unit area of receiver aperture. The results address the problem of application optimization (loss varies) as opposed to the problem of optimization of a design for a specific application (loss fixed). A reasonable range of values for the primary independent variable L (the average reradiative and convective loss per unit area of receiver aperture) and a reasonable set of design assumptions were first established. The optimum receiver aperture area, number and spacings of heliostats, and field boundary were then determined for two tower focal heights and for each value of L. From this, the solar subsystem performance for each optimized system was calculated. Heliostat field analysis and optimization required a detailed computational analysis. A significant modification to the standard method of solving the optimization equations, effectively a decoupling of the solution process into collector and receiver subsystem parts, greatly aided the analysis. Results are presented for tower focal heights of 150 and 180 m. Values of L ranging from 0.04 to 0.50 MW m('-2) were considered, roughly corresponding to working fluid temperatures (at receiver exit) in the range of 650 to 1650 C. As L increases over this range, the receiver thermal efficiency and the receiver interception factor decrease. The optimal power level drops by almost half, and the cost per unit of energy produced increases by about 25% for the base case set of design assumptions. The resulting decrease in solar subsystem efficiency (relative to the defined annual input energy) from 0.57 to 0.35 is about 40% and is a

  17. Variation and Sexual Dimorphism of Body Size in the Plateau Brown Frog along an Altitudinal Gradient

    Institute of Scientific and Technical Information of China (English)

    Xueyun FENG; Wei CHEN; Junhua HU; Jianping JIANG

    2015-01-01

    Variation in body size and sexual size dimorphism (SSD) can have important consequences for animal ecology, behavior, population dynamics and the evolution of life-history traits. Organisms are expected to be larger in colder climate (i.e., Bergmann’s rule) and SSD varies with body size (i.e., Rensch’s rule). However, the underlying mechanisms are still elusive. The plateau brown frog (Rana kukunoris), a medium-sized anuran species with female-biased SSD, is endemic to the Qinghai-Tibetan Plateau (QTP). From 1797 m (Maoxiang’ping) to 3453 m (Heihe’qiao) in the eastern margin of the QTP, we surveyed 10 populations of R. kukunoris and collected phalanges and snout vent length (SVL) data for 258 adult individuals (199 males versus 59 females). Based on these data, we explored how body size and SSD varying along the altitudinal gradient and examined the corresponding effects of temperature. We found body size to be larger at higher altitude for males but not for females, with likely effects from the temperature on the variation in male body size. Sex differences in growth rates may be the main cause of the variation in SSD. Our results suggested that only males follow the Bergmann’s rule and variation in SSD of R. kukunoris do not support the Rensch’s rule and its inverse. Therefore, the variations of body size can be different between sexes and the applicability of both Bergmann’s rule and Rensch’s rule should depend on species and environment where they live.

  18. Structure of dung beetle communities in an altitudinal gradient of neotropical dry forest.

    Science.gov (United States)

    Domínguez, D; Marín-Armijos, D; Ruiz, C

    2015-02-01

    To understand the effects of global warming in tropical insect communities, it is necessary to comprehend how such communities respond to different abiotic factors that covariate with altitude. In this study, we partially answer this question applied to dung beetle communities distributed along an altitudinal gradient. The sampling was conducted in seven stations 100 m apart each in altitude in a dry mountain scrub in southern Ecuador. A total of 7422 individuals belonging to six species were captured. Canthon balteatus Boheman was the most abundant with 6502 individuals, and Onoreidium ohausi (Arrow) was the least abundant with 20 individuals. We found significant changes in the structure of the dung beetle communities with altitude. Two abiotic factors showed a relationship with the abundance pattern for all species (altitude, Z = 0.011, p < 0.01, and temperature, Z = 0.859, p < 0.01). Canthon balteatus Boheman showed a positive relationship with altitude (Z = 1.422, p < 0.001) and temperature (Z = 1.121, p < 0.001), Dichotomius problematicus (Lüederwaldt) a positive relationship with precipitation (Z = 0.113, p < 0.001), and Malagoniella cupreicollis (Waterhouse) a positive relationship with temperature (Z = 0.668, p < 0.001) and negative with precipitation (Z = -0.189, p < 0.001). Phanaeus achilles Boheman, Onthophagus sp., and O. ohausi (Arrow) did not show any relationship with the studied variables, nor was the richness correlated with the studied variables. These results suggest that the effects of global warming over dung beetle communities will be difficult to predict because of species-specific responses to global warming. PMID:26013011

  19. Specialization and phenological synchrony of plant-pollinator interactions along an altitudinal gradient.

    Science.gov (United States)

    Benadi, Gita; Hovestadt, Thomas; Poethke, Hans-Joachim; Blüthgen, Nico

    2014-05-01

    One of the most noticeable effects of anthropogenic climate change is the shift in timing of seasonal events towards earlier occurrence. The high degree of variation in species' phenological shifts has raised concerns about the temporal decoupling of interspecific interactions, but the extent and implications of this effect are largely unknown. In the case of plant-pollinator systems, more specialized species are predicted to be particularly threatened by phenological decoupling, since they are assumed to be less flexible in the choice of interaction partners, but until now this hypothesis has not been tested. In this paper, we studied phenology and interactions of plant and pollinator communities along an altitudinal gradient in the Alps as a model for the possible effects of climate change in time. Our results show that even relatively specialized pollinators were much more flexible in their use of plant species as floral resources than their local flower visitation suggested. We found no relationship between local specialization of pollinators and the consistency of their visitation patterns across sites, and also no relationship between specialization and phenological synchrony of pollinators with particular plants. Thus, in contrast to the conclusions of a recent simulation study, our results suggest that most pollinator species included in this study are not threatened by phenological decoupling from specific flowering plants. However, the flexibility of many rarely observed pollinator species remains unknown. Moreover, our results suggest that specialized flower visitors select plant species based on certain floral traits such as the length of the nectar holder tube. If that is the case, the observed flexibility of plant-pollinator interactions likely depends on a high degree of functional redundancy in the plant community, which may not exist in less diverse systems. PMID:24219131

  20. Forest structure, diversity and regeneration potential along altitudinal gradient in Dhanaulti of Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Sushil Saha

    2016-07-01

    Full Text Available Aim of the study: The aim of the present study was to understatnd the forest composition, structure, diversity and regeneration potential along altitudinal gradient. Area of study: The study was carried out in Dhanaulti forest which falls under temperate region of Garhwal Himalaya in Uttarakhand state, India. Material and Methods: Vegetation analysis was carried out using 10 quadrats at each altitude using a quadrate size of 10×10 m2. In each quadrate, categories of trees >30 cm cbh were considered as trees, 10-30cm cbh as saplings and <10 cm cbh as seedlings. The data were quantitatively analyzed. Main results: In upper and middle altitudes, Cedrus deodara was reported dominant tree whereas, in lower altitude Quercus leucotrichophora was reported dominant. Tree density was highest in lower altitude which reduced middle and upper altitudes whereas, total basal cover increased with increasing altitude. The increasing total basal cover with altitude could be because of the presence of Cedrus deodara trees having higher girth classes. In tree, sapling and seedling layers, diversity (H and equitabiltiy (EC decreased with increasing altitude. However, concentrations of dominace (CD and beta diversity (BD have shown reverse trend with H and EC which increased with increasing altitudes, in each layer of tree, sapling and seedling. The distribution pattern of most species in all layers of trees, saplings and seedlings was contagious. The regeneration potential of the species has shown that some of the species in the absence of tree layer are still regenerating particularly, Rhododendron arboreum, Benthamidia capitata, Neolitsea pallens etc. It indicates that most of the species are shifting upward as they are getting suitable conditions. Research highlights: Altitude influence species composition, diversity and regeneration potential of species. Key words: Distribution pattern; tree diversity; regeneration; mountains; temperate; Himalaya.

  1. Reciprocal effects of treatment-induced increases in exercise and improved eating, and their psychosocial correlates, in obese adults seeking weight loss: a field-based trial

    OpenAIRE

    James J. Annesi; Porter, Kandice J

    2013-01-01

    Background A better understanding of interrelations of exercise and improved eating, and their psychosocial correlates of self-efficacy, mood, and self-regulation, may be useful for the architecture of improved weight loss treatments. Theory-based research within field settings, with samples possessing high probabilities of health risks, might enable rapid application of useful findings. Methods Adult volunteers with severe obesity (body mass index [BMI] 35–50 kg/m2; age = 43.0 ± 9.5 y; 83% f...

  2. Evaluation of observable phase space by fast ion loss detector by calculating particle orbits in consideration of plasma facing components and three dimensional magnetic field

    Science.gov (United States)

    Shinohara, Kouji; Kim, Junghee; Kim, Jun Young; Rhee, Tongnyeol

    2016-11-01

    The orbits of lost ions can be calculated from the information obtained by a fast ion loss detector (FILD). The orbits suggest a source of the lost fast ions in a phase space. However, it is not obvious whether an observable set of orbits, or phase space, of a FILD appropriately covers the region of interest to be investigated since the observable phase space can be affected by plasma facing components (PFCs) and a magnetic configuration. A tool has been developed to evaluate the observable phase space of FILD diagnostic by calculating particle orbits by taking the PFCs and 3D magnetic field into account.

  3. Estructura de una comunidad de líquenes y morfologia del género sticta (stictaceae) en un gradiente altitudinal

    OpenAIRE

    Watteijne Ceron, Benicia; Perez Quintero, Alvaro Luis

    2010-01-01

    La distribución y el crecimiento de los líquenes están condicionados por diferentes factores ambientales, entre estos la variación en gradientes altitudinales. En la cordillera Oriental de los Andes de Colombia, no se han realizado estudios sobre zonación altitudinal de líquenes. En este trabajo se estudiaron las variaciones en la estructura de la comunidad de líquenes epifitos en un gradiente altitudinal (2000-2600 m) en el PNN Tatamá. Se encontró que con el aumento en altura hay una disminu...

  4. Use of NeuroEyeCoach™ to Improve Eye Movement Efficacy in Patients with Homonymous Visual Field Loss

    Science.gov (United States)

    Zihl, Josef

    2016-01-01

    Visual field deficits are common in patients with damaged retinogeniculostriate pathways. The patient's eye movements are often affected leading to inefficient visual search. Systematic eye movement training also called compensatory therapy is needed to allow patients to develop effective coping strategies. There is a lack of evidence-based, clinical gold-standard registered medical device accessible to patients at home or in clinical settings and NeuroEyeCoach (NEC) is developed to address this need. In three experiments, we report on performance of patients on NEC compared to the data obtained previously on the earlier versions of the search task (n = 32); we assessed whether the self-administered computerised tasks can be used to monitor the progress (n = 24) and compared the findings in a subgroup of patients to a healthy control group. Performance on cancellation tasks, simple visual search, and self-reported responses on activities of daily living was compared, before and after training. Patients performed similarly well on NEC as on previous versions of the therapy; the inbuilt functionality for pre- and postevaluation functions was sensitive to allowing assessment of improvements; and improvements in patients were significantly greater than those in a group of healthy adults. In conclusion, NeuroEyeCoach can be used as an effective rehabilitation tool to develop compensatory strategies in patients with visual field deficits after brain injury.

  5. Experimental quantification of radiocesium recycling in a coniferous tree after aerial contamination: Field loss dynamics, translocation and final partitioning.

    Science.gov (United States)

    Thiry, Y; Garcia-Sanchez, L; Hurtevent, P

    2016-09-01

    After foliar interception of radioactive atmospheric fallout by forest trees, the short-term recycling dynamics of radiocesium from the tree to the soil as well as within the tree is a primary area of uncertainty in the modeling of the overall cycle. The partitioning of radiocesium transfers in a spruce tree exposed to aerial deposits was investigated during one growth season to reveal the dynamics and significance of underlying processes. The rate of radiocesium loss resulting from foliage leaching (wash-off) was shown to have a functional dependence on the frequency of rainy episodes in a first early stage (weathering 60% of initial contamination during 70 days) and on the amount of precipitation in a second stage (weathering 10% of initial deposits during the following 80 days). A classical single exponential decay model with offset and continuous time as predictor lead to a removal half-life t1/2 of intercepted radiocesium of 25 days. During the growth season, the similar pattern of the internal (134)Cs content in new shoots and initially contaminated foliage confirmed that radiocesium was readily absorbed from needle surfaces and efficiently translocated to growing organs. In the crown, a pool of non-leachable (134)Cs (15-30%) was associated with the abiotic layer covering the twigs and needle surfaces. At the end of the growth season, 30% of the initial deposits were relocated to different tree parts, including organs like stemwood (5%) and roots (6%) not directly exposed to deposition. At the scale of the tree, 84% of the residual activity was assimilated by living tissues which corresponds to a foliar absorption rate coefficient of 0.25 year(-1) for modeling purposes. According to the significant amount of radiocesium which can be incorporated in tree through foliar uptake, our results support the hypothesis that further internal transfers could supply the tree internal cycle of radiocesium extensively, and possibly mask the contribution of root uptake for

  6. Energy Loss of a Non-Accelerating Quark Moving in a Strongly Coupled $\\mathcal{N}=4$ SYM Vacuum or Quark-Gluon Plasma in Strong Magnetic Field

    CERN Document Server

    Mamo, Kiminad A

    2016-01-01

    We show that a massless quark moving at the speed of light $v=1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ super Yang-Mills (SYM) vacuum in the presence of strong magnetic field $\\mathcal{B}$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$. In addition, we show that a heavy quark of mass $M$ moving at near the speed of light $v^2=v_{*}^2=1-\\frac{4\\pi^2 T^2}{\\mathcal{B}}\\simeq1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ SYM quark-gluon plasma at finite temperature $T$, in the presence of strong magnetic field $\\mathcal{B}\\gg T^2$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}v_{*}^2\\simeq-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$.

  7. Biological transfer and loss of /sup 36/Cl-labeled DDT in an old-field ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Peterle, T.J.

    1979-04-20

    An enclosed 10-acre old-field plot treated in June 1969, with chlorine-36 labeled DDT was sampled each year from 1969 through 1974 to monitor the fate of the insecticide in the soil and biota. In order to provide data on compartmentalization of DDT in the vegetation, invertebrates and vertebrates inhabiting the plot, sampling was carried out to estimate both body burdens of DDT and biomass of populations. Another aspect of this study, the determination of rates of accumulation of residues by invertebrates and vertebrates, has been reported previously (Forsyth and Peterle 1973; Forsyth et al. 1975; Peterle 1975). This report describes (a) temporal patterns of DDT residues in soil and biota from 1969 through 1974 and (b) quantities of DDT held in the soil and biotic compartments of the ecosystem. Part II of the report is concerned with translocation and accumulation of/sup 14/C-DDT.

  8. Gaseous mercury emissions from soil following forest loss and land use changes: Field experiments in the United States and Brazil

    Science.gov (United States)

    Carpi, Anthony; Fostier, Anne H.; Orta, Olivia R.; dos Santos, Jose Carlos; Gittings, Michael

    2014-10-01

    Forest ecosystems are a sink of atmospheric mercury, trapping the metal in the canopy, and storing it in the forest floor after litter fall. Fire liberates a portion of this mercury; however, little is known about the long-term release of mercury post deforestation. We conducted two large-scale experiments to study this phenomenon. In upstate New York, gaseous mercury emissions from soil were monitored continually using a Teflon dynamic surface flux chamber for two-weeks before and after cutting of the canopy on the edge of a deciduous forest. In Brazil, gaseous mercury emissions from soil were monitored in an intact Ombrophilous Open forest and an adjacent field site both before and after the field site was cleared by burning. In the intact forest, gaseous mercury emissions from soil averaged -0.73 ± 1.84 ng m-2 h-1 (24-h monitoring) at the New York site, and 0.33 ± 0.09 ng m-2 h-1 (daytime-only) at the Brazil site. After deforestation, gaseous mercury emissions from soil averaged 9.13 ± 2.08 ng m-2 h-1 in New York and 21.2 ± 0.35 ng m-2 h-1 at the Brazil site prior to burning. Gaseous mercury emissions averaged 74.9 ± 0.73 ng m-2 h-1 after burning of the cut forest in Brazil. Extrapolating our data, measured over several weeks to months, to a full year period, deforested soil is estimated to release an additional 2.30 g ha-1 yr-1 of gaseous mercury to the atmosphere in the Brazilian experiment and 0.41 g ha-1 yr-1 in the New York experiment. In Brazil, this represents an additional 50% of the mercury load released during the fire itself.

  9. Monte Carlo Studies of the Radiation Fields in the Linac Coherent Light Source Undulators and of the Corresponding Signals in the Cerenkov Beam Loss Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Santana Leitner, Mario; Fasso, Alberto; Fisher, Alan S.; Nuhn, Heinz D.; /SLAC; Dooling, Jeffrey C.; Berg, William; Yang, Bin X.; /Argonne

    2010-09-14

    In 2009 the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Center started free electron laser (FEL) operation. In order to continue to produce the bright and short-pulsed x-ray laser demanded by FEL scientists, this pioneer hard x-ray FEL requires a perfectly tailored magnetic field at the undulators, so that the photons generated at the electron wiggling path interact at the right phase with the electron beam. In such a precise system, small (>0.01%) radiation-induced alterations of the magnetic field in the permanent magnets could affect FEL performance. This paper describes the simulation studies of radiation fields in permanent magnets and the expected signal in the detectors. The transport of particles from the radiation sources (i.e. diagnostic insert) to the undulator magnets and to the beam loss monitors (BLM) was simulated with the intra nuclear cascade codes FLUKA and MARS15. In order to accurately reproduce the optics of LCLS, lattice capabilities and magnetic fields were enabled in FLUKA and betatron oscillations were validated against reference data. All electron events entering the BLMs were printed in data files. The paper also introduces the Radioactive Ion Beam Optimizer (RIBO) Monte Carlo 3-D code, which was used to read from the event files, to compute Cerenkov production and then to simulate the optical coupling of the BLM detectors, accounting for the transmission of light through the quartz.

  10. Mitochondrial DNA sequence variation in Drosophilid species (Diptera: Drosophilidae) along altitudinal gradient from Central Himalayan region of India

    Indian Academy of Sciences (India)

    MANISHA SARSWAT; SAURABH DEWAN; RAJENDRA SINGH FARTYAL

    2016-06-01

    Central Himalayan region of India encompasses varied ecological habitats ranging from near tropics to the mid-elevation forests dominated by cool-temperate taxa. In past, we have reported several new records and novel species from Uttarakhand state of India. Here, we assessed genetic variations in three mitochondrial genes, namely, 16S rRNA, cytochrome c oxidase subunit I and cytochrome c oxidase subunit II (COI and COII) in 26 drosophilid species collected along altitudinal transect from 550 to 2700 m above mean sea level. In the present study, overall 543 sequences were generated, 82 for 16S rRNA, 238 forCOI, 223 for COII with 21, 47 and 45 mitochondrial haplotypes for 16S rRNA, COI and COII genes,respectively. Almost all species were represented by 2–3 unique mitochondrial haplotypes, depicting a significant impact of environmental heterogeneity along altitudinal gradient on genetic diversity. Also for the first time, molecular data of some rare species like Drosophila mukteshwarensis , Liodrosophila nitida, Lordiphosa parantillaria , Lordiphosa ayarpathaensis ,Scaptomyza himalayana,Scaptomyza tistai , Zaprionus grandis and Stegana minuta are provided to public domains through this study.

  11. Stage-specific effects of candidate heterochronic genes on variation in developmental time along an altitudinal cline of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Julián Mensch

    Full Text Available BACKGROUND: Previously, we have shown there is clinal variation for egg-to-adult developmental time along geographic gradients in Drosophila melanogaster. Further, we also have identified mutations in genes involved in metabolic and neurogenic pathways that affect development time (heterochronic genes. However, we do not know whether these loci affect variation in developmental time in natural populations. METHODOLOGY/PRINCIPAL FINDINGS: Here, we constructed second chromosome substitution lines from natural populations of Drosophila melanogaster from an altitudinal cline, and measured egg-adult development time for each line. We found not only a large amount of genetic variation for developmental time, but also positive associations of the development time with thermal amplitude and altitude. We performed genetic complementation tests using substitution lines with the longest and shortest developmental times and heterochronic mutations. We identified segregating variation for neurogenic and metabolic genes that largely affected the duration of the larval stages but had no impact on the timing of metamorphosis. CONCLUSIONS/SIGNIFICANCE: Altitudinal clinal variation in developmental time for natural chromosome substitution lines provides a unique opportunity to dissect the response of heterochronic genes to environmental gradients. Ontogenetic stage-specific variation in invected, mastermind, cricklet and CG14591 may affect natural variation in development time and thermal evolution.

  12. Altitudinal and climatic associations of seed dormancy and flowering traits evidence adaptation of annual life cycle timing in Arabidopsis thaliana.

    Science.gov (United States)

    Vidigal, Deborah S; Marques, Alexandre C S S; Willems, Leo A J; Buijs, Gonda; Méndez-Vigo, Belén; Hilhorst, Henk W M; Bentsink, Leónie; Picó, F Xavier; Alonso-Blanco, Carlos

    2016-08-01

    The temporal control or timing of the life cycle of annual plants is presumed to provide adaptive strategies to escape harsh environments for survival and reproduction. This is mainly determined by the timing of germination, which is controlled by the level of seed dormancy, and of flowering initiation. However, the environmental factors driving the evolution of plant life cycles remain largely unknown. To address this question we have analysed nine quantitative life history traits, in a native regional collection of 300 wild accessions of Arabidopsis thaliana. Seed dormancy and flowering time were negatively correlated, indicating that these traits have coevolved. In addition, environmental-phenotypic analyses detected strong altitudinal and climatic clines for most life history traits. Overall, accessions showing life cycles with early flowering, small seeds, high seed dormancy and slow germination rate were associated with locations exposed to high temperature, low summer precipitation and high radiation. Furthermore, we analysed the expression level of the positive regulator of seed dormancy DELAY OF GERMINATION 1 (DOG1), finding similar but weaker altitudinal and climatic patterns than seed dormancy. Therefore, DOG1 regulatory mutations are likely to provide a quantitative molecular mechanism for the adaptation of A. thaliana life cycle to altitude and climate. PMID:26991665

  13. Classification and ordination of main plant communities along an altitudinal gradient in the arid and temperate climates of northeastern Mexico.

    Science.gov (United States)

    Castillón, Eduardo Estrada; Arévalo, José Ramón; Quintanilla, José Ángel Villarreal; Rodríguez, María Magdalena Salinas; Encina-Domínguez, Juan Antonio; Rodríguez, Humberto González; Ayala, César Martín Cantú

    2015-10-01

    Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.

  14. Altitudinal variation of phenolic contents in flowering heads of Arnica montana cv. ARBO: a 3-year comparison.

    Science.gov (United States)

    Spitaler, Renate; Winkler, Andrea; Lins, Isabella; Yanar, Sema; Stuppner, Hermann; Zidorn, Christian

    2008-03-01

    In continuation of our studies of altitudinal effects on secondary metabolite profile of flowering heads from taxa of the Asteraceae, we investigated phenolic contents and radical scavenging potential from cultivated plants of Arnica montana cv. ARBO during the growing seasons 2003, 2004, and 2005. By conducting experiments on potted plants, we excluded that differences in phenolic contents from plants grown at different altitudes were related primarily to differences in soil composition at these sites. To assess altitudinal and interseasonal variation, plants of A. montana cultivar ARBO were grown in nine experimental plots at altitudes between 590 and 2,230 m at Mount Patscherkofel near Innsbruck, Austria. In all growing seasons and regardless of the soil the plants were grown in, the proportion of flavonoids with vicinal-free hydroxy groups in ring B to flavonoids lacking this feature, and the total amount of caffeic acid derivatives, significantly increased with elevation. These increases of antioxidant phenolics corresponded to an increase of the radical scavenging potential of extracts from plants grown at different altitudes. The results are discussed in regard to previous studies that suggest that enhanced UV-B radiation and decreased temperatures trigger augmented biosynthesis of UV-absorbing and antioxidant phenolics in higher plants.

  15. Leaf macro-and micro-morphological altitudinal variability of Carpinus betulus in the Hyrcanian forest (Iran)

    Institute of Scientific and Technical Information of China (English)

    Iman Chapolagh Paridari; Seyed Gholamali Jalali; Ali Sonboli; Mehrdad Zarafshar; Piero Bruschi

    2013-01-01

    We investigated the altitudinal variation of Carpinus betulus L.in the Hyrcanian forest using leaf macro-morphological and micro-morphological traits.We collected a total of 1600 leaves from two locations.In each location,we sampled six populations along an altitudinal gradient ranging from 100 m to 1,150 m.We found that trees in the higher elevations have smaller leaf lamina than those in the lower elevations.In contrast,leaf mass per area was high at low altitudes and increased newly at the higher ones.Stomatal dimension was negatively correlated with elevation,while stomatal density was positively correlated with elevation.We also found that two transects showed the same plasticity trend.Leaf area showed the highest plasticity,while the number of veins showed the lowest plasticity.This study shows that altitude,and related temperature and rainfall,represents an important driving force in Carpinus betulus leaf morphological variation.Moreover,our results suggest that leaf area,leaf mass per area and stomatal density could influence the species responses to different ecological conditions.

  16. Diversity and distribution patterns of Pronophilina butterflies (Lepidoptera: Nymphalidae: Satyrinae) along an altitudinal transect in north-western Ecuador.

    Science.gov (United States)

    Pyrcz, Tomasz W; Wojtusiak, Janusz; Garlacz, Rafaa

    2009-01-01

    Samplings of Pronophilina, a species-rich group of neotropical montane butterflies, were carried out along an elevational transect in Ecuador to assess the effect of altitude on their distribution patterns, diversity and community structure. All diversity indices were significantly correlated with altitude. Maximum diversity expressed in species-richness, Shannon index and Fisher alpha was recorded at 2600 m. Two assemblages of species were identified in the lower (below 2100 m) and upper (above 2300 m) sections of the transect by means of correspondence (CA) and cluster analysis. A comparison of Sørensen similarity coefficients showed lower values, thus higher turnover in the intermediate elevational band. Several closely related morphologically and ecologically species were found to have mutually exclusive altitudinal distribution patterns. A comparison with similar studies in Venezuela, Colombia and Peru revealed far reaching congruency of the patterns of altitudinal diversity of Pronophilina in distant areas of the Andes. In particular, the Shannon index reaches its maximum values at 2600-2850 m, which invariably correspond to ca. 400-500 m below the upper limit of cloud forest. Increase of diversity of Pronophilina with altitude is marginally related to higher limited resource availability. The lower pressure of predators and parasites at higher elevation can contribute with higher abundance, but cannot be directly correlated with higher diversity. Higher diversity is related with intrisic characteristics of the group, such as aggregated diversity by overlapping of elevational faunal assemblages and higher speciation ratio towards high elevations, particularly near timberline.

  17. Classification and ordination of main plant communities along an altitudinal gradient in the arid and temperate climates of northeastern Mexico

    Science.gov (United States)

    Castillón, Eduardo Estrada; Arévalo, José Ramón; Quintanilla, José Ángel Villarreal; Rodríguez, María Magdalena Salinas; Encina-Domínguez, Juan Antonio; Rodríguez, Humberto González; Ayala, César Martín Cantú

    2015-10-01

    Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.

  18. CONSTRAINING THE ALTITUDINAL RANGE OF SUB-HORIZONTAL DENUDATION SURFACES IN WALES, U.K., USING THE ELEVATIONRELIEF RATIO

    Directory of Open Access Journals (Sweden)

    Matt D Rowberry

    2008-08-01

    Full Text Available This paper uses the elevation-relief ratio to constrain the horizontal and vertical extent of sub-horizontaldenudation surfaces in Wales, United Kingdom. The elevation-relief ratio has been chosen as the appropriategeomorphological parameter as it allows such surfaces to be mapped analytically, even in areas that havebeen subjected to considerable linear denudation; thus, the technique is applicable in a wide range oftopographic settings. For the first time, the elevation-relief ratio has been calculated through the interrogationof the SRTM DEM, using ESRI ArcMap 9.2 GIS software; the methodology has been described in detail.Five sub-horizontal denudation surfaces are recognized at between 40-90 m asl, 118-132 m asl, 173-187m asl, 219-229 m asl, and 385-520 m asl. The number and altitudinal range of these surfaces has not beenrecognized in any previous study; the enduring tripartite division of the Welsh landscape envisaged byBrown (1960 must now be rejected, both in terms of the number of surfaces that may be recognized andtheir altitudinal range.

  19. Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2008-01-01

    The objective of this study was to explore the altitudinal decrease in local richness of stream macroinvertebrates. I compared the explicatory power of a mid-domain effect (MDE) null model and a number of selected contemporary ecological variables, with a special emphasis on the altitude-mediated......The objective of this study was to explore the altitudinal decrease in local richness of stream macroinvertebrates. I compared the explicatory power of a mid-domain effect (MDE) null model and a number of selected contemporary ecological variables, with a special emphasis on the altitude......'s alpha index and rarefied richness) decreased with increasing altitude. The MDE null model, water temperature and dissolved oxygen also decreased with altitude, while other measured variables were uncorrelated with altitude. Minimum oxygen saturation had the highest explanatory power of the density......-corrected Fisher's alpha and rarefied richness (R = 0.48 and 0.52, respectively), but also minimum temperature (R = 0.48 and 0.41) and the MDE null model (R = 0.48 and 0.46) correlated significantly. Multiple regression analyses using several predictive variables showed that oxygen saturation had the greatest and...

  20. Diversity and altitudinal distribution of Chrysomelidae (Coleoptera in Peregrina Canyon, Tamaulipas, Mexico

    Directory of Open Access Journals (Sweden)

    Uriel Jeshua Sánchez-Reyes

    2014-06-01

    species assemblages of Chrysomelidae. The highest abundance was obtained during the late dry season, whereas diversity indices were highest during the early wet season. The present work represents the first report of the altitudinal variation in richness, abundance, and diversity of Chrysomelidae in Mexico. These results highlight the importance of conservation of this heterogeneous habitat and establish baseline data for Chrysomelidae richness and diversity for the region.

  1. Cultivable bacterial diversity along the altitudinal zonation and vegetation range of tropical Eastern Himalaya.

    Science.gov (United States)

    Lyngwi, Nathaniel A; Koijam, Khedarani; Sharma, D; Joshi, S R

    2013-03-01

    The Northeastern part of India sprawls over an area of 262 379km2 in the Eastern Himalayan range. This constitutes a biodiversity hotspot with high levels of biodiversity and endemism; unfortunately, is also a poorly known area, especially on its microbial diversity. In this study, we assessed cultivable soil bacterial diversity and distribution from lowlands to highlands (34 to 3 990m.a.s.l.). Soil physico-chemical parameters and forest types across the different altitudes were characterized and correlated with bacterial distribution and diversity. Microbes from the soil samples were grown in Nutrient, Muller Hinton and Luria-Bertani agar plates and were initially characterized using biochemical methods. Parameters like dehydrogenase and urease activities, temperature, moisture content, pH, carbon content, bulk density of the sampled soil were measured for each site. Representative isolates were also subjected to 16S rDNA sequence analysis. A total of 155 cultivable bacterial isolates were characterized which were analyzed for richness, evenness and diversity indices. The tropical and sub-tropical forests supported higher bacterial diversity compared to temperate pine, temperate conifer, and sub-alpine rhododendron forests. The 16S rRNA phylogenetic analysis revealed that Firmicutes was the most common group followed by Proteobacreria and Bacteroidetes. Species belonging to the genera Bacillus and Pseudomonas were the most abundant. Bacterial CFU showed positive but insignificant correlation with soil parameters like pH (r=0.208), soil temperature (r=0.303), ambient temperature (r=0.443), soil carbon content (r=0.525), soil bulk density (r=0.268), soil urease (r=0.549) and soil dehydrogenase (r=0.492). Altitude (r=-0.561) and soil moisture content (r=-0.051) showed negative correlation. Altitudinal gradient along with the vegetation and soil physico-chemical parameters were found to influence bacterial diversity and distribution. This study points out that this is

  2. Effect of Tillage and Non-tillage Agricultural Practice on Nitrogen Losses as NO and N2O in Tropical Corn Fields at Guarico State, Venezuela.

    Science.gov (United States)

    Marquina, S.; Rojas, A.; Donoso, L.; Rasse, R.; Giuliante, A.; Corona, O.; Perez, T.

    2007-12-01

    We evaluated the effect of agricultural practices on NO and N2O emissions from corn fields at Northern Guárico, one of Venezuelan largest cereal production regions. Historically, the most common agricultural practice in these regions has been mono cropping. Tillage (T) and non-tillage (NT) of soils represent approximately 30 and 70% of the planted area, respectively. Comparative studies of the nitrogen losses associated with these agricultural practices are not available for these regions. This study was conducted at the farm "Tierra Nueva", Guárico State (9° 23' 33'' N, 66° 38' 30'' W) in two corn fields under tillage and non-tillage agricultural practice during the growing season (June-August 2006). A dry tropical forest, the primary ecosystem of the region, was evaluated for the same period of time. The corn and the forest fields were adjacent; therefore, they were exposed to the same meteorological conditions. The mean annual precipitation of the area is 622±97.3 mm (last 5 years). The soils are Vertisols (Typic Haplusterts). Nutrient soil concentrations (as nitrate and ammonium), water soil content and pH soil were measured in the fields for the same period of time. Soils were fertilized and planted simultaneously by a planting machine provided with a furrow opener where the fertilizer and seeds are incorporated between 0-10 cm depths. Tillage soils were fertilized on June 1st 2006 with 65 kgN/ha of NPK (13:18:16/3MgO, 3S; N as NH4Cl), whereas non-tillage soils were fertilized the next day with 56 kgN/ha of NPK (12:25:12/3MgO, 3S; N as NH4Cl). Second fertilization of both fields was done thirty-seven days later by broadcast adding 58 kgN/ha approximately, using nitrophosphate as fertilizer (NP 33-3: 33% N total; 16.7% N- NO3- and 16.6% N- NH4+). In general, NO and N2O soil emissions from both corn fields increased after fertilization events, and depend on water soil content and nutrient soil concentration. N2O soil emissions were 11 and 9 times larger in

  3. Modelling decomposition of standard plant material along an altitudinal gradient: A re-analysis of data of Coûteaux et al.

    NARCIS (Netherlands)

    Braakhekke, W.G.; Bruijn, de A.M.G.

    2007-01-01

    We explored an alternative method to analyse data of Cou¿teaux et al. [2002, Soil Biology and Biochemistry 34, 69-78] on the decomposition of a standard organic material in six soils along an altitudinal gradient in the Venezuelan Andes (65-3968 m a.s.l.). Cou¿teaux et al., fitted separate two-compo

  4. Altitudinal occurrence of non-native plant species (neophytes and their habitat affinity to anthropogenic biotopes in conditions of South-Western Slovakia

    Directory of Open Access Journals (Sweden)

    Beniak Michal

    2015-03-01

    Full Text Available Many ecological studies showed that species density (the number of species per unit area in nonnative organism groups of the mountain areas decreases with increasing altitude. The aim of the paper is to determine the variability in the incidence of non-native plant species (neophytes associated with the change in altitude and links of the invading taxons to reference habitat types, as well as their links to three ecologically very similar, however in natural conditions, different areas. In general, the most invaded habitats are those which are highly influenced by human activities. Firstly, data collection was conducted through field mapping of build-up areas in South-western Slovakia. Subsequently, with the assistance of ordination methods, we evaluated the level of association of invasive neophytes according to the set objectives. We found that altitude was an important factor determining variability of invasive neophytes’ occurrence. Total amount of habitats with invasive neophytes’ occurrence showed a linear increase along the altitudinal gradient. Many invasive neophytes adapted to abandoned habitats of upland territory were also able to grow along roads, and vice versa, abandoned and unused habitats of lowland areas created conditions for many typical invasive neophytes occurring along roads and habitats of gardens and yards. Railways of lowland areas provided habitats and means of spread of invasive woody neophytes. Gardens and yards were important sources of alien neophytes in all observed territories. Invasive neophyte Aster novi-belgii can be described as a very variable species tolerant to a wide range of factors limiting the spread of species along the elevation gradient.

  5. Splice Loss of Graded-Index Fibers: Accurate Semianalytical Descriptions Using Nelder-Mead Nonlinear Unconstrained Optimization with Three-Parameter Fundamental Modal Field

    Directory of Open Access Journals (Sweden)

    Raja Roy Choudhury

    2013-01-01

    Full Text Available A faster and accurate semianalytical formulation with a robust optimization solution for estimating the splice loss of graded-index fibers has been proposed. The semianalytical optimization of modal parameters has been carried out by Nelder-Mead method of nonlinear unconstrained minimization suitable for functions which are uncertain, noisy, or even discontinuous. Instead of normally used Gaussian function, as the trial field for the fundamental mode of graded-index optical fiber a novel sinc function with exponentially and R-3/2 (R is the normalized radius of the optical fiber decaying trailing edge has been used. Due to inclusion of three parameters in the optimization of fundamental modal solution and application of an efficient optimization technique with simple analytical expressions for various modal parameters, the results are found to be accurate and computationally easier to find than the standard numerical method solution.

  6. Energy loss of a nonaccelerating quark moving through a strongly coupled N =4 super Yang-Mills vacuum or plasma in strong magnetic field

    Science.gov (United States)

    Mamo, Kiminad A.

    2016-08-01

    Using AdS /CFT correspondence, we find that a massless quark moving at the speed of light v =1 , in arbitrary direction, through a strongly coupled N =4 super Yang-Mills (SYM) vacuum at T =0 , in the presence of strong magnetic field B , loses its energy at a rate linearly dependent on B , i.e., d/E d t =-√{λ/} 6 π B . We also show that a heavy quark of mass M ≠0 moving at near the speed of light v2=v*2=1 -4/π2T2 B ≃1 , in arbitrary direction, through a strongly coupled N =4 SYM plasma at finite temperature T ≠0 , in the presence of strong magnetic field B ≫T2, loses its energy at a rate linearly dependent on B , i.e., d/E d t =-√{λ/}6 π B v*2≃-√{λ/}6 π B . Moreover, we argue that, in the strong magnetic field B ≫T2 (IR) regime, N =4 SYM and adjoint QCD theories (when the adjoint QCD theory has four flavors of Weyl fermions and is at its conformal IR fixed point λ =λ*) have the same microscopic degrees of freedom (i.e., gluons and lowest Landau levels of Weyl fermions) even though they have quite different microscopic degrees of freedom in the UV when we consider higher Landau levels. Therefore, in the strong magnetic field B ≫T2 (IR) regime, the thermodynamic and hydrodynamic properties of N =4 SYM and adjoint QCD plasmas, as well as the rates of energy loss of a quark moving through the plasmas, should be the same.

  7. Persistent toxic substances in soils and waters along an altitudinal gradient in the Laja River Basin, Central Southern Chile.

    Science.gov (United States)

    Barra, Ricardo; Popp, Peter; Quiroz, Roberto; Bauer, Coretta; Cid, Hernan; von Tümpling, Wolf

    2005-02-01

    In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine

  8. Nitrogen Losses as N2O and NO After Non-tillage Agricultural Practice in a Tropical Corn Field at Guarico State, Venezuela.

    Science.gov (United States)

    Perez, T. J.; Gil, J. A.; Marquina, S.; Donoso, L. E.; Trumbore, S. E.; Tyler, S. C.

    2005-12-01

    Historically, the most common agricultural practice in Northern Guárico, one of Venezuelan largest cereal production regions, has been mono cropping, with extensive tillage operations that usually causes rapid soil degradation and nitrogen losses. Alternative production systems, such as non-tillage agricultural practices, have been extensively implemented during the last few years. However, studies of the nitrogen losses associated with these alternative practices are not widely available. This study was conducted at "Fundo Tierra Nueva", Guárico State (9°23'33" N, 66° 38'30" W) in a corn field under the non-tillage agricultural practice, during the growing season June-August 2005. The soils are Vertisols (Typic Haplusterts). The area has two well defined precipitation seasons: wet (May-October) and dry (November-April). The mean annual precipitation of the area is 622±97.3 mm (last 5 years). Because the irrigation of the crop depends on precipitation, the planting is scheduled during the months of highest precipitation in June-July. We measured nitrogenous gas emissions (N2O and NO), concentrations of total nitrogen (NT), NH4+ and NO3- in soil (0-100 cm) after fertilization to estimate the nitrogen losses. We also measured CO2 emissions to evaluate the relationship of microbial respiration to the emissions of nitrogenous trace gases. Soils were fertilized with 54 kgN/ha (NPK 12:24:12, nitrogen as NH4Cl) and planted simultaneously by a planting machine provided with a furrow opener where the fertilizer and seeds are incorporated between 0-10 cm depth. Thirty days later, soils were fertilized by broadcast addition of 18 kgN/ha (as ammonium nitrate). Nitrous oxide emissions were highly dependant on the water content. Prior to fertilization N2O emissions were very low. Right after fertilization the emissions increased by a factor of 5 compared to pre-fertilization levels and increased to 100 times larger after the first heavy rain. NO emissions did not increase

  9. Altitudinal zonation among lizards of the genus Liolaemus: questions answered and unanswered questions Zonación altitudinal en lagartijas del género Liolaemus: preguntas respondidas y pendientes

    Directory of Open Access Journals (Sweden)

    JOHN H. CAROTHERS

    2001-06-01

    Full Text Available We review factors influencing Liolaemus distributions in the central Chilean Andes and suggest areas of future research. Our previous studies reveal that lizard parasites (ectoparasitic mites and ticks, and the endoparasite Plasmodium do not set Liolaemus altitudinal limits. Thermal tolerances do not appear to limit altitudinal distributions, although cold ambient temperatures dictate that only live-bearing species can occur above 2,400 m elevation. Three Liolaemus species specialize on elevationally restricted microhabitats. Liolaemus tenuis is found exclusively in or at the base of trees, which are typically below 1,800 m. Liolaemus leopardinus specializes on large rocky outcrops found at high altitudes. Liolaemus monticola uses smaller rocks: oviparity set its upper distributional limit on two transects, but on one transect this lizard and its rocky habitat virtually disappeared above 1,500 m. Interspecific competition among Liolaemus appeared unrelated to elevational distribution. We found no instances of parapatric distributions among pairs of Liolaemus species having similar niche requirements. Other researchers have found that predation does not correlate with elevation: its role in determining lizard species distributions depends on both predator and prey identities. We conclude that factors setting distributional limits of Liolaemus species vary depending on individual circumstances in time and space: where physiology may be relevant on one transect, preferred microhabitat availability may be important in anotherRevisamos los factores que influyen sobre las distribuciones de Liolaemus en los Andes del centro de Chile y sugerimos futuras avenidas de investigación. Nuestros estudios previos revelan que los parásitos (garrapatas y ácaros ectoparásitos y el endoparásito Plasmodium no influyen sobre los límites altitudinales de Liolaemus. Las tolerancias térmicas tampoco parecen limitar dichas distribuciones altitudinales, aunque las

  10. Potential of Gdgts as Temperature Proxies Along Altitudinal Transects in East Africa

    Science.gov (United States)

    Coffinet, Sarah; Huguet, Arnaud; Omuombo, Christine; Williamson, David; Fosse, Céline; Anquetil, Christine; Derenne, Sylvie

    2014-05-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are lipids of high molecular weight and include the isoprenoid GDGTs (iGDGTs) produced by Archaea and the branched GDGTs (brGDGTs) produced by unknown bacteria. Several indices were developed to describe the relationship between GDGT distribution and environmental parameters: the TEX86 (tetraether index of tetraethers consisting of 86 carbons), based on the relative abundances of iGDGTs in sediments, and the MBT (methylation index of branched tetraethers) and CBT (cyclisation ratio of branched tetraethers), based on the relative abundance of brGDGTs in soils. The TEX86 was shown to correlate well with water surface temperature, and the MBT and CBT with mean annual air temperature (MAAT) and soil pH. The GDGTs are increasingly used as temperature proxies. In this study, 41 surface soils were sampled along two altitudinal transects, from 500 to 2800 meters in Mount Rungwe (South western, Tanzania) and from 1897 to 3268 meters in Mount Kenya (Central Kenya). MAAT was reconstructed along the two transects using the MBT/CBT proxies. A linear correlation between the MBT/CBT-derived temperatures and the altitude (R2=0.83) was obtained by combining results of the two transects. The reconstructed temperature lapse rate (0.5 ° C/100 m) was consistent with the one determined from temperature measurements at six altitudes. These results show that the MBT/CBT is a suitable and robust temperature proxy in East Africa. In Mt. Rungwe soil samples, the TEX86 index, which was mainly used to reconstruct water surface temperatures until now, was found to vary linearly with altitude (R2=0.50). Such a relationship between TEX86 and altitude in organic soils has also been recently noticed in Mt. Xiangpi, China (Liu et al., 2013; R2=0.68). The adiabatic cooling of air with altitude could explain the TEX86 variation with altitude. If such a relationship is confirmed, the use of the TEX86 as a temperature proxy could be extended to soil

  11. Beam Loss in Linacs

    CERN Document Server

    Plum, M A

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  12. Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

    Science.gov (United States)

    Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Boeckx, Pascal; Kearsley, Elizabeth; Cizungu, Landry; Verbeeck, Hans

    2016-04-01

    Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Africa, focussing on shifts in carbon allocation, forest structure and functional composition. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed adaption mechanisms are.

  13. Studies Regarding the Colonization Capacity of Soils with Permanent Nitrogen Fixating Bacteria, Located on Different Altitudinal Levels

    Directory of Open Access Journals (Sweden)

    Carmen Dragomir

    2012-05-01

    Full Text Available The determination of the colonization capacity with permanent nitrogen fixating bacteria has been achieved indirectly through the method of using soil extracts, taken from the rhizosphere of leguminous species existing in the 4 types of permanent grasslands, located on different altitudinal levels (90m, 330m, 900m, 1800m. Treatments with soil extracts taken have been made at three species of legumes (Lotus corniculatus, Trifolium repens, Trifolium pratense, seeded on a sown perlite layer and grown in the growth chamber. Between the total amount of nodosities formed and the altitude of grasslands there is a negative correlation. At treatments with extracts taken from grasslands situated between 90-330m, there has been observed the highest number of nodosities formed on roots of tested leguminous species.

  14. Latitudinal and altitudinal variation of size distribution of stratospheric aerosols inferred from SAGE aerosol extinction coefficient measurements at two wavelengths

    Science.gov (United States)

    Yue, G. K.; Deepak, A.

    1984-01-01

    A method of retrieving aerosol size distribution from the measured extinction of solar radiation at wavelengths of 0.45 microns and 1.0 microns has recently been proposed. This method is utilized to obtain latitudinal and altitudinal variations of size distributions of stratospheric aerosols from the Stratospheric Aerosol and Gas Experiment data for March 1979. Small particles are found in the lower stratosphere of the tropical region, and large particles are found at higher altitudes and latitudes in both hemispheres. Results of this study are consistent with the suggestion that the upper troposphere in tropical regions is a source of condensation nuclei in the stratosphere, and they become mature as they move to higher altitudes and latitude.

  15. The biological activity of chernozems in the Central Caucasus Mountains (Terskii variant of altitudinal zonality), Kabardino-Balkaria

    Science.gov (United States)

    Gedgafova, F. V.; Uligova, T. S.; Gorobtsova, O. N.; Tembotov, R. Kh.

    2015-12-01

    Some parameters of the biological activity (humus content; activity of hydrolytic enzymes invertase, phosphatase, urease; and the intensity of carbon dioxide emission) were studied in the chernozems of agrocenoses and native biogeocenoses in the foothills of the Caucasus Mountains representing the Terskii variant of the altitudinal zonality. The statistically significant differences were revealed between the relevant characteristics of the soils of the agrocenoses and of the native biogeocenoses. The integral index of the ecological-biological state of the soils was used to estimate changes in the biological activity of the arable chernozems. The 40-60% decrease of this index in the cultivated chernozems testified to their degradation with a decrease in fertility and the disturbance of ecological functions as compared to these characteristics in the virgin chernozems.

  16. Hearing Loss

    Science.gov (United States)

    ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Tools & ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Ask ...

  17. An altitudinal cline in UV floral pattern corresponds with a behavioral change of a generalist pollinator assemblage.

    Science.gov (United States)

    Koski, Matthew H; Ashman, Tia-Lynn

    2015-12-01

    Spatial variation in pollinator communities or behaviors can underlie floral diversification. Floral traits in the UV spectrum are common and mediate plant-pollinator interactions, but the role of pollinators in driving or maintaining their geographic variation has not been fully explored. We identify an altitudinal cline of increasing relative size of the UV bullseye pattern in Argentina anserina (Rosaceae) flowers, and assess whether pollination context contributes to clinal variation. At four sites that varied in altitude, we document the pollinator assemblage, and pollinator preference and visitation behavior. We then determine how pollinator visits affected pollen receipt and export. Finally, we describe how the functional relationship between UV floral phenotype and pollen receipt changed with altitude. Floral UV bullseye size increased with altitude, which corresponded with a change from a hymenopteran- to a dipteran-dominated pollinator assemblage. While dipteran and hymenopteran preferences for bullseye size were similar, flowers with large bullseyes received more foraging visits than those with small bullseyes at higher altitude. The reverse was observed at the lower altitudes; pollinators approached large-bullseye flowers often but rarely foraged. These differences are expected to affect fitness because foraging visits increased pollen export and receipt. Indeed, when natural variation in bullseye size was considered, it had a stronger effect on pollen receipt than other traits (flower size, display, or color). Plants with larger bullseyes tended to receive more pollen at the highest-altitude site, while those with smaller ones received more pollen at the lowest-altitude site. Results suggest that altitudinal changes in preference and behavior of the overall pollinator assemblage, but not differential preferences of pollinator taxonomic groups, could contribute to clinal variation in a UV floral trait for a generalist-pollinated plant. PMID:26909439

  18. Population Fluctuation and Altitudinal Distribution of Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) in Avocado (Lauraceae) in Morelos, Mexico

    Science.gov (United States)

    García-Palacios, Daniel; Bautista-Martínez, Néstor; Lagunes-Tejeda, Ángel; Carrillo-Sánchez, José Luis; Nieto-Ángel, Daniel; García-Gutiérrez, Cipriano

    2016-01-01

    Although whiteflies Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) are considered a secondary pest of avocado crops, their presence and the damages that they cause can decrease crop vigor and affect production. The objective of the present work was to determine the population fluctuation and altitudinal distribution of the T. perseae Nakahara whitefly in avocado trees, as well as to determine the number of possible generations in one year. The study was done in three orchards in Morelos state, located at different altitudes, from February 2014 to April 2015. Samplings were done every 21 days from 10 randomly chosen trees in each orchard. The samples were taken randomly from the middle stratus (1.6 m in height) of each tree; in buds or young leaves for the number of adults and leaves only for nymphs. Additionally, two yellow traps (7 × 14 cm) with glue were placed in each tree for adult samplings. Data were collected regarding vegetative budding, rainfall, relative humidity, and temperature. T. perseae was present in all three sampled orchards, with a greater presence in the lowest orchard, during the whole study period. In the orchard with the lowest altitudinal gradient (1,736 masl), 11 whitefly generations developed; 10 generations developed in the medium gradient orchard (1,934 masl); and 8 generations developed in the highest orchard (2,230 masl). The adults showed a positive relationship with regard to vegetative buds, while the nymphs had a negative relationship with regard to relative humidity. The rest of the parameters showed diverse effects on the species depending on the altitude of the orchard. PMID:27658809

  19. Efecto del gradiente altitudinal sobre la vegetación de las sierras de Lihue Calel (La Pampa, Argentina

    Directory of Open Access Journals (Sweden)

    Mónica B. Mazzola

    2008-07-01

    Full Text Available Las Sierras de Lihue Calel constituyen un sistema serrano de escasa altitud ubicado en el sudeste de la provincia del Monte. Nuestro objetivo fue evaluar las variaciones espaciales y temporales del microhábitat, asociadas con la topografía e identificar el efecto que estas tienen sobre la distribución de las especies vegetales. Se establecieron transectas de exposición norte y sur y se caracterizó el ambiente de las mismas a lo largo del gradiente altitudinal. Se midieron temperatura, viento, radiación, propiedades edáficas y la abundancia-cobertura de las plantas vasculares. La ladera norte recibe mayor radiación y es más cálida y rocosa que la ladera sur. Factores ligados a la exposición y elevación como la temperatura, humedad, pH del suelo y la rocosidad explicaron el 64% de la variación ambiental en las laderas. La composición florística siguió un patrón de tolerancia a la sequía y disponibilidad de luz, donde las especies C4 y CAM dominaron en la ladera norte más cálida y las C3 en la sur más sombreada y fresca. Nuestras observaciones reconocen la importancia de los cambios topográficos en los factores ambientales y su efecto sobre la distribución de las especies en los sistemas serranos de poca altitud.Efect of the altitudinal gradient on the vegetation of Lihue Calel sierras (La Pampa, Argentina

  20. The roles of genetic drift and natural selection in quantitative trait divergence along an altitudinal gradient in Arabidopsis thaliana.

    Science.gov (United States)

    Luo, Y; Widmer, A; Karrenberg, S

    2015-02-01

    Understanding how natural selection and genetic drift shape biological variation is a central topic in biology, yet our understanding of the agents of natural selection and their target traits is limited. We investigated to what extent selection along an altitudinal gradient or genetic drift contributed to variation in ecologically relevant traits in Arabidopsis thaliana. We collected seeds from 8 to 14 individuals from each of 14 A. thaliana populations originating from sites between 800 and 2700 m above sea level in the Swiss Alps. Seed families were grown with and without vernalization, corresponding to winter-annual and summer-annual life histories, respectively. We analyzed putatively neutral genetic divergence between these populations using 24 simple sequence repeat markers. We measured seven traits related to growth, phenology and leaf morphology that are rarely reported in A. thaliana and performed analyses of altitudinal clines, as well as overall QST-FST comparisons and correlation analyses among pair-wise QST, FST and altitude of origin differences. Multivariate analyses suggested adaptive differentiation along altitude in the entire suite of traits, particularly when expressed in the summer-annual life history. Of the individual traits, a decrease in rosette leaf number in the vegetative state and an increase in leaf succulence with increasing altitude could be attributed to adaptive divergence. Interestingly, these patterns relate well to common within- and between-species trends of smaller plant size and thicker leaves at high altitude. Our results thus offer exciting possibilities to unravel the underlying mechanisms for these conspicuous trends using the model species A. thaliana.

  1. 山地垂直带谱研究评述%Mountain Altitudinal Belt:A Review

    Institute of Scientific and Technical Information of China (English)

    孙建; 程根伟

    2014-01-01

    山地垂直带谱研究是地学地域分异规律研究的重要内容之一,垂直带谱受土壤、气候和生物条件的影响,呈现不同的分布特征。在气候变化的影响下,垂直带谱也发生着剧烈的变化,并对气候变化起指示作用。本文通过梳理山地垂直带谱研究的主要历程,就山地垂直带谱的成因和格局以及研究方法的革新进行了探讨,并对我国的山地垂直带谱研究以及落基山脉和阿尔卑斯山脉等其他地域的研究状况进行综合论述。分析认为利用现有的观测数据,如气象、生物、土壤和地形等方面资料,研究山地垂直带谱的演替过程以及格局变化,关注未来气候变化情景下垂直带谱对于生态安全和环境保护显得尤为重要。同时,多学科的介入和交叉知识的融合对山地垂直带谱研究有着重要的意义,如研究带谱的形成,需要对地质构造、气象成因、植物生理、土壤生态等各方面的知识,在大尺度的研究中,遥感技术以及计算机信息工程要纳入其中。目前山地垂直带谱的理论基础也无法满足科学研究的需求,理论化研究需要进一步推进。综述期望为我国山地科学研究、综合地域分异、地理区划和环境变化研究提供一定的参考。%Mountain altitudinal belt is one of the important contents for studying geographic differentiation. Altitudinal belt is influenced by soil, climate and biological conditions. Mountain altitudinal belt has been changed with climate change recently. In present article, the development of mountain altitudinal belt research was analyzed, main features of the altitudinal belt was explored, the spatial pattern as well as the innovation of research method was discussed, and the mountain altitudinal belt researches in China, the Rocky Mountains, the Alps and other regions were comprehensively reviewed. Thus, we hold that using the observed datum (weather

  2. A comparative assessment of the biological properties of soils in the cultural and native cenoses of the Central Caucasus (using the example of the Terskii variant of altitudinal zonality in Kabardino-Balkaria)

    Science.gov (United States)

    Gorobtsova, O. N.; Gedgafova, F. V.; Uligova, T. S.; Tembotov, R. Kh.

    2016-01-01

    The biological properties of the most widespread automorphic and hydromorphic soils of cultural and native cenoses in the Terskii variant of the altitudinal zonality (Kabardino-Balkaria) are compared. The data on the humus reserves in the 0- to 20-cm soil layer and those on the carbon content in the microbial biomass calculated on the basis of the results of substrate-induced respiration measurements are presented. The share of carbon in the microbial biomass of the total organic carbon in the soils was determined. Long-term (more than 70 years) farming on the studied soils significantly changed their biological properties. The humus content and its reserves became lower by 25-40%. The physiological activity of the microbial biomass in the cultural soils decreased by more than 60%. Presently, the soils of the cultural cenoses function as an entire natural system, but at a lower level of fertility; the loss of more than 30% of the bioorganic potential (the critical threshold of soil system stability) indicates the disturbance of soil ecological functions, their stability, and the capability of self-restoration.

  3. How do two Lupinus species respond to temperature along an altitudinal gradient in the Venezuelan Andes? ¿Cómo responden dos especies de Lupinus a la temperatura en un gradiente altitudinal en los Andes venezolanos?

    Directory of Open Access Journals (Sweden)

    FERMÍN RADA

    2008-09-01

    Full Text Available Temperature determines plant formations and species distribution along altitudinal gradients. Plants in the tropical high Andes, through different physiological and morphological characteristics, respond to freezing night temperatures and high daytime energy inputs which occur anytime of the year. The main objective of this study was to characterize day and night temperature related responses of two Lupinus species with different altitudinal ranges (L. meridanus, 1,800-3,600 and L. eromonomos, 3,700-4,300 m of altitude. Are there differences in night low temperature resistance mechanisms between the species along the gradient? How do these species respond, in terms of optimum temperature for photosynthesis, to increasing altitude? Lupinus meridanus shows frost avoidance, in contrast to L. eromonomos, which tolerates freezing at higher altitudes. Optimum temperature for photosynthesis decreases along the gradient for both species. Maximum C0(2 assimilation rates were higher in L. meridanus, while L. eromonomos showed decreasing C0(2 assimilation rates at the higher altitude. In most cases, measured daily leaf temperature is always within the 80 % of optimum for photosynthesis. L. meridanus7 upper distribution limit seems to be restricted by cold resistance mechanisms, while L. eromonomos7 to a combination of both cold resistance and to C0(2 assimilation responses at higher altitudes.La temperatura determina las formaciones vegetales y la distribución de especies a lo largo de gradientes altitudinales. Las plantas en los altos Andes tropicales, a través de diferentes características morfológicas y fisiológicas, responden a temperaturas congelantes nocturnas y altas entradas energéticas durante el día en cualquier momento del año. El objetivo principal de este estudio fue caracterizar las respuestas relacionadas con temperaturas diurnas y nocturnas en dos especies de Lupinus con diferente distribución altitudinal (L. meridanus, 1

  4. Variations in carbon isotope ratios of C_3 plants and distribution of C_4 plants along an altitudinal transect on the eastern slope of Mount Gongga

    Institute of Scientific and Technical Information of China (English)

    LI JiaZhu; WANG GuoAn; LIU XianZhao; HAN JiaMao; LIU Min; LIU XiaoJuan

    2009-01-01

    Variations in carbon isotopic ratios (δ~(13)C) of C_3 plants and distribution of C_4 plants were investigated along an altitudinal transect on the eastern slope of Mount Gongga,and the environmental effects on them were discussed,it is shown that plants with C_4 photosynthetic pathway mainly occur at altitudes below 2100 m a.a.l.,suggesting that the low summer temperature is responsible for the distributional pattern.In addition,δ~(13)C of C_3 plants increases with elevation at the region above 2000 m a.s.l,with the characteristics of humid climate,and the increase rate in δ~(13)C for C_3 plants is about 1.3‰ per kilometer.Temperature determines the altitudinal trend of δ~(13)C.

  5. Análisis de las poblaciones de briófitos y líquenes en el gradiente altitudinal de una carretera en Cundinamarca, Colombia

    Directory of Open Access Journals (Sweden)

    Linares Édgar L.

    2006-12-01

    Full Text Available En una carretera, a lo largo de un gradiente altitudinal, en Cundinamarca, Colombia, se estudiaron musgos asociados a sustratos de concreto, encontrando dos tipos de zonación, una asociada a ambientes generados por el borde de la carretera “Zonación Transversal”; y otra, “Zonación Altitudinal”, relacionada con el gradiente altitudinal. Diagramas de zonación fueron construidos a partir de datos de presencia, analizados con el Índice de Similaridad de Sorensen y a partir de datos de porcentaje de cobertura por especie. En ambos casos se observó, que el establecimiento de musgos está determinado por la humedad, la cual depende de la porosidad del concreto, microtopografía, ángulo de inclinación, sombra y altitud.

  6. Variations in carbon isotope ratios of C3 plants and distribution of C4 plants along an altitudinal transect on the eastern slope of Mount Gongga

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Variations in carbon isotopic ratios (δ 13C) of C3 plants and distribution of C4 plants were investigated along an altitudinal transect on the eastern slope of Mount Gongga, and the environmental effects on them were discussed. It is shown that plants with C4 photosynthetic pathway mainly occur at altitudes below 2100 m a.s.l., suggesting that the low summer temperature is responsible for the distributional pattern. In addition, δ 13C of C3 plants increases with elevation at the region above 2000 m a.s.l. with the characteristics of humid climate, and the increase rate in δ 13C for C3 plants is about 1.3‰ per kilometer. Temperature determines the altitudinal trend of δ 13C.

  7. Distribución altitudinal de las aves en una zona prioritaria en Sinaloa y Durango, México Altitudinal distribution of birds in a priority area in Sinaloa-Durango, Mexico

    Directory of Open Access Journals (Sweden)

    Ma Nelle Medina-Macías

    2010-08-01

    Full Text Available En este estudio se documentan los patrones de riqueza de especies y endemismo con respecto a un gradiente altitudinal (300-2 800 m snm en la región del Espinazo del Diablo (estados de Durango y Sinaloa. Se registró un total de 209 especies de aves, que aunadas a los registros previos en literatura y colecciones conforman una lista regional de 229 especies. Los 3 métodos empleados para reconocer la existencia de asociaciones faunísticas a lo largo del gradiente - el fenograma de similitud, las curvas de atenuación y el análisis de TWINSPAN-, coincidieron en la existencia de 3 pisos altitudinales, por lo que se observa claramente que existe una división de la avifauna en el transecto. La zona reviste una gran importancia para la conservación de los recursos biológicos de México, pues además de contener el reducto de bosque montano húmedo más norteño del oeste de Mesoamérica, la avifauna también resulta importante tanto por su riqueza específica como por el endemismo y presencia de especies de especial interés.We document patterns of species richness and endemism in an elevational gradient (300 to 2 800 m located in the Espinazo del Diablo region (states of Durango and Sinaloa, as well as its significance for the conservation of the avifauna, that is a global priority due to the presence of endemic and highly endangered taxa. We recorded a total of 209 species of birds in the fieldwork, and adding the records from literature and collections, the list increases to 229 bird species in the area. The 3 methods used for recognizing faunistic assemblages along the elevational gradient -phenetic similarity analysis, faunal congruence curves, and TWINSPAN- recognized 3 altitudinal associations, 1 in the lowlands and 2 in the higher elevations, what represents a clear division of the avifauna. The area is a conservation priority in Mexico, because is the northernmost relict of cloud forest in Mesoamerica, and holds an extraordinary

  8. Diversity and community structure of testate amoebae (protista) in tropical montane rain forests of southern Ecuador: altitudinal gradient, aboveground habitats and nutrient limitation.

    OpenAIRE

    Krashevs'ka, Valentyna

    2009-01-01

    The tropical Andes in southern Ecuador constitute a hotspot of plant (especially trees and bryophytes) and animal (especially birds, bats, arctiid and geometrid mothes) diversity. However, data on small animals such as testate amoebae as an important component of the soil and aboveground community are lacking. Variations in density, diversity and community structure of testate amoebae along altitudinal transects in tropical regions are largely unknown. Testate amoebae colonize almost any habi...

  9. Genetic structure along an altitudinal gradient in Lippia origanoides, a promising aromatic plant species restricted to semiarid areas in northern South America

    OpenAIRE

    Vega-Vela, Nelson Enrique; Sánchez, María Isabel Chacón

    2012-01-01

    The genetic diversity and population structure of Lippia origanoides, a species of the Verbenaceae family that shows promise as a crop plant, was investigated along an altitudinal gradient in the basin of the Chicamocha River in northeastern Colombia. The economic importance of the species, quality of its essential oils, and the fact that it is restricted to some few semiarid areas in northern South America may put the species at risk in a scenario of uncontrolled harvest of natural populatio...

  10. Abundance and Diversity of Bacterial, Archaeal, and Fungal Communities Along an Altitudinal Gradient in Alpine Forest Soils: What Are the Driving Factors?

    Science.gov (United States)

    Siles, José A; Margesin, Rosa

    2016-07-01

    Shifts in soil microbial communities over altitudinal gradients and the driving factors are poorly studied. Their elucidation is indispensable to gain a comprehensive understanding of the response of ecosystems to global climate change. Here, we investigated soil archaeal, bacterial, and fungal communities at four Alpine forest sites representing a climosequence, over an altitudinal gradient from 545 to 2000 m above sea level (asl), regarding abundance and diversity by using qPCR and Illumina sequencing, respectively. Archaeal community was dominated by Thaumarchaeota, and no significant shifts were detected in abundance or community composition with altitude. The relative bacterial abundance increased at higher altitudes, which was related to increasing levels of soil organic matter and nutrients with altitude. Shifts in bacterial richness and diversity as well as community structure (comprised basically of Proteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes) significantly correlated with several environmental and soil chemical factors, especially soil pH. The site at the lowest altitude harbored the highest bacterial richness and diversity, although richness/diversity community properties did not show a monotonic decrease along the gradient. The relative size of fungal community also increased with altitude and its composition comprised Ascomycota, Basidiomycota, and Zygomycota. Changes in fungal richness/diversity and community structure were mainly governed by pH and C/N, respectively. The variation of the predominant bacterial and fungal classes over the altitudinal gradient was the result of the environmental and soil chemical factors prevailing at each site. PMID:26961712

  11. Predicted altitudinal shifts and reduced spatial distribution of Leishmania infantum vector species under climate change scenarios in Colombia.

    Science.gov (United States)

    González, Camila; Paz, Andrea; Ferro, Cristina

    2014-01-01

    Visceral leishmaniasis (VL) is caused by the trypanosomatid parasite Leishmania infantum (=Leishmania chagasi), and is epidemiologically relevant due to its wide geographic distribution, the number of annual cases reported and the increase in its co-infection with HIV. Two vector species have been incriminated in the Americas: Lutzomyia longipalpis and Lutzomyia evansi. In Colombia, L. longipalpis is distributed along the Magdalena River Valley while L. evansi is only found in the northern part of the Country. Regarding the epidemiology of the disease, in Colombia the incidence of VL has decreased over the last few years without any intervention being implemented. Additionally, changes in transmission cycles have been reported with urban transmission occurring in the Caribbean Coast. In Europe and North America climate change seems to be driving a latitudinal shift of leishmaniasis transmission. Here, we explored the spatial distribution of the two known vector species of L. infantum in Colombia and projected its future distribution into climate change scenarios to establish the expansion potential of the disease. An updated database including L. longipalpis and L. evansi collection records from Colombia was compiled. Ecological niche models were performed for each species using the Maxent software and 13 Worldclim bioclimatic coverages. Projections were made for the pessimistic CSIRO A2 scenario, which predicts the higher increase in temperature due to non-emission reduction, and the optimistic Hadley B2 Scenario predicting the minimum increase in temperature. The database contained 23 records for L. evansi and 39 records for L. longipalpis, distributed along the Magdalena River Valley and the Caribbean Coast, where the potential distribution areas of both species were also predicted by Maxent. Climate change projections showed a general overall reduction in the spatial distribution of the two vector species, promoting a shift in altitudinal distribution for L

  12. Impact of altitudinal variability on streamflows in mountainous catchments under changing climate (Upper Indus Basin), Himalayas Pakistan

    Science.gov (United States)

    Khan, K. M.; Yaseen, M.

    2014-12-01

    Pakistan's economy is based on agriculture that is highly dependent on water resources originating in the mountain sources of the Upper Indus Basin (UIB). Various rivers i.e. Chitral, Swat, Kabul, Hunza, Gilgit, Astore, Shigar, Shyok & tributaries contribute water to main Indus River. The elevation of UIB ranges from 254 m to 8570 m a.m.s.l. Changes in climate and related hydrological impacts vary in space and time as affected by local climatic and topographic settings. So, the objective of this study was to assess the climate change and related hydrological impacts resulting from altitudinal variability. Trend analyses were performed by applying Mann-Kendall and Sen's method was applied to estimate slope time series that indicates changes in river flows. The results of this study indicate that maximum temperature in annual, winter, spring and autumn seasons has increased with increased in altitude while annual, winter and autumn minimum temperature has decreased with increased in altitude for the period (1961-2011). Moreover, annual, winter, summer and autumn precipitation has been decreased. The impact of altitudinal variability under changing climate yields that annual and seasonal streamflows in River Indus (at Kharmong, Alam Br. and Khairabad), Sawat (at Kalam) and Kabul (at Nowshera) have decreased whereas in River Shoyk (9%), Shigar (7%) and Indus at Kachura (5%) have been increased. However, annual runoff in Gilgit (1%) and Hunza River (18%) has increased by increasing 2 % annual temperature. A seasonal correlation coefficient between temperature and streamflow has the positive correlation in most of the sub-basins of UIB for both spring and summer. With increased 1 oC temperature in spring yields increased streamflow for rives Gilgit, Chitral, Astore, Shoyk, Shigar, Indus at Kachura & Kharmong and Hunza with percentage of 19, 5, 11, 15, 9, 7, 1 and 12 respectively. The prevailing trends and variability, caused by climate change, have an effect on the flows

  13. Predicted altitudinal shifts and reduced spatial distribution of Leishmania infantum vector species under climate change scenarios in Colombia.

    Science.gov (United States)

    González, Camila; Paz, Andrea; Ferro, Cristina

    2014-01-01

    Visceral leishmaniasis (VL) is caused by the trypanosomatid parasite Leishmania infantum (=Leishmania chagasi), and is epidemiologically relevant due to its wide geographic distribution, the number of annual cases reported and the increase in its co-infection with HIV. Two vector species have been incriminated in the Americas: Lutzomyia longipalpis and Lutzomyia evansi. In Colombia, L. longipalpis is distributed along the Magdalena River Valley while L. evansi is only found in the northern part of the Country. Regarding the epidemiology of the disease, in Colombia the incidence of VL has decreased over the last few years without any intervention being implemented. Additionally, changes in transmission cycles have been reported with urban transmission occurring in the Caribbean Coast. In Europe and North America climate change seems to be driving a latitudinal shift of leishmaniasis transmission. Here, we explored the spatial distribution of the two known vector species of L. infantum in Colombia and projected its future distribution into climate change scenarios to establish the expansion potential of the disease. An updated database including L. longipalpis and L. evansi collection records from Colombia was compiled. Ecological niche models were performed for each species using the Maxent software and 13 Worldclim bioclimatic coverages. Projections were made for the pessimistic CSIRO A2 scenario, which predicts the higher increase in temperature due to non-emission reduction, and the optimistic Hadley B2 Scenario predicting the minimum increase in temperature. The database contained 23 records for L. evansi and 39 records for L. longipalpis, distributed along the Magdalena River Valley and the Caribbean Coast, where the potential distribution areas of both species were also predicted by Maxent. Climate change projections showed a general overall reduction in the spatial distribution of the two vector species, promoting a shift in altitudinal distribution for L

  14. Optical dark field and electron energy loss imaging and spectroscopy of symmetry-forbidden modes in loaded nanogap antennas (Presentation Recording)

    Science.gov (United States)

    Brintlinger, Todd; Herzing, Andrew; Long, James P.; Vurgaftman, Igor; Stroud, Rhonda; Simpkins, Blake S.

    2015-09-01

    Theoretical work has identified a new type of hybrid nanoresonator akin to a loaded-gap antenna, wherein the gap between two collinearly aligned metal nanorods is filled with active dielectric material. The gap optical load has a profound impact on resonances supported by such a "nanogap" antenna, and thus provides opportunity for (i) active modulation of the antenna resonance and (ii) delivery of substantial energy to the gap material. To this end, we have (i) used a bottom-up technique to fabricate nanogap antennas (Au/CdS/Au); (ii) characterized the optical modes of individual antennas with polarization- and wavevector-controlled dark-field microscopy; (iii) mapped the spatial profiles of the dominant modes with electron energy loss spectroscopy and imaging; and (iv) utilized full-wave finite-difference time-domain simulations to reveal the nanoscopic origin of the radiating modes supported on such nanogap antennas. In addition to conventional transverse and longitudinal resonances, these loaded nanogap antennas support a unique symmetry-forbidden gap-localized transverse mode arising from the splitting of degenerate transverse modes located on the two gap faces. This previously unobserved mode is strong (E2 enhanced ~20), tightly localized in the nanoscopic (~30 nm separation) gap region, and is shown to red-shift with decreased gap size and increased gap dielectric constant. In fact, the mode is highly suppressed in air-gapped structures which may explain its absence from the literature to date. Understanding the complex modal structure supported on hybrid nanosystems is necessary to enable the multi-functional components many seek.

  15. [Inner Ear Hearing Loss].

    Science.gov (United States)

    Hesse, G

    2016-06-01

    Hearing loss is one of the most dominant handicaps in modern societies, which additionally very often is not realized or not admitted. About one quarter of the general population suffers from inner ear hearing loss and is therefore restricted in communicational skills. Demographic factors like increasing age play an important role as well as environmental influences and an increasing sound and noise exposure especially in leisure activities. Thus borders between a "classical" presbyacusis - if it ever existed - and envirionmentally induced hearing loss disappear. Today restrictions in hearing ability develop earlier in age but at the same time they are detected and diagnosed earlier. This paper can eventually enlighten the wide field of inner ear hearing loss only fragmentarily; therefore mainly new research, findings and developments are reviewed. The first part discusses new aspects of diagnostics of inner ear hearing loss and different etiologies. PMID:27259171

  16. Memory loss

    Science.gov (United States)

    A person with memory loss needs a lot of support. It helps to show the person familiar objects, music, or and photos or play familiar music. Write down when the person should take any medicine or do other ...

  17. Richness and diversity of aphids (Homoptera, Aphididae along an altitudinal gradient in the Serra do Mar, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Crisleide Maria Lazzarotto

    1998-12-01

    Full Text Available The lack of bioecological studies on aphids in regions with complex floristic and faunistic structure, such as the Atlantic Tropical Rain Forest, lead to the initiation of this research. The objectives were to determine species richness and diversity of aphids and to investigate the influence of altitude and environmental perturbations on aphid populations. The collections were made with yellow pan traps at 11 sites with altitudes from -10 m to 1000 m above sea level (a.s.l., in the Serra do Mar, Paraná, Brazil, from December 1993 to December 1994. Richness and diversity of aphids were greatest at 85 m a.s.l. This site was characterized by three distinct floral communities: primary vegetation, secondaiy vegetation in successional stages, and secondary vegetation subject to regular mowing. No pattern in the number or kinds of species could be established along the altitudinal gradient. These results, indicate that several factors interact, but especially floristic composition and climatic conditions, to determine aphidofauna richness and diversity in this region of the Atlantic Tropical Rain Forest.

  18. Vascular plant species richness in relation to altitudinal and slope gradients in mountain landscapes of central norway

    Science.gov (United States)

    Holten, Jarle I.

    Local plant ecological investigations in the central Norwegian mountains in 1992-1997 have shown some interesting features regarding the variability of vascular plant species richness along altitudinal gradients. The material reveals two peaks of vascular plant species richness with increasing elevation, a lowland peak at 0-400 m a.s.l. and a peak at the timberline area (upper part of the northern boreal zone), around the inflection line. Mountains with highly acidic bedrock have a vegetation discontinuity around the transition between discontinuous and continuous permafrost (1500 m in the Dovrefjell area), with a change from dwarf shrubs to more graminoid life forms. The angle of slope is decisive for soil-forming processes. The instability of steep slopes prevents the formation and accumulation of organic top-soils. The data show a high, positive correlation between the slope of habitat plots and the richness of vascular plant species, in both the forested and the alpine zones. A working hypothesis is put forward that, due to high substratum instability, steep terrain encourages high species richness due to the greater openness of habitats and the higher pH of the top-soils. It is suggested that this effect of local topography on species richness is strongest around the inflection line.

  19. What do metabolic rates tell us about thermal niches? Mechanisms driving crayfish distributions along an altitudinal gradient.

    Science.gov (United States)

    Stoffels, Rick J; Richardson, Adam J; Vogel, Matthew T; Coates, Simon P; Müller, Warren J

    2016-01-01

    Humans are rapidly altering thermal landscapes, so a central challenge to organismal ecologists is to better understand the thermal niches of ectotherms. However, there is much disagreement over how we should go about this. Some ecologists assume that a statistical model of abundance as a function of habitat temperature provides a sufficient approximation of the thermal niche, but ecophysiologists have shown that the relationship between fitness and temperature can be complicated, and have stressed the need to elucidate the causal mechanisms underlying the response of species to thermal change. Towards this end, we studied the distribution of two crayfishes, Euastacus woiwuru and Euastacus armatus, along an altitudinal gradient, and for both species conducted experiments to determine the temperature-dependence of: (1) aerobic scope (the difference between maximum and basal metabolic rate; purported to be a proxy of the thermal niche); and (2) burst locomotor performance (primarily fuelled using anaerobic pathways). E. woiwuru occupied cooler habitats than E. armatus, but we found no difference in aerobic scope between these species. In contrast, locomotor performance curves differed significantly and strongly between species, with peak locomotor performances of E. woiwuru and E. armatus occurring at ~10 and ~18 °C, respectively. Crayfish from different thermal landscapes may have similar aerobic thermal performance curves but different anaerobic thermal performance curves. Our results support a growing body of literature implying different components of ectotherm fitness have different thermal performance curves, and further challenge our understanding of the ecology and evolution of thermal niches. PMID:26440800

  20. A floristic study on Mazibon and Sibon protected forests, Ramsar, across the altitudinal gradient (300-2300 m

    Directory of Open Access Journals (Sweden)

    Alireza Naqinezhad

    2011-01-01

    Full Text Available The Mazibon and Sibon forests with the area of approximately 15000 hectars are located in 60 kilometers south of Ramsar and between 300-2300 m a.s.l. The occurrence of a variety of riverine, forest, rangeland and ecotone ecosystems within the area provide well stablished habitats for different plants and animals. In orther to preserve biodiversity, this area was designated as no-hunting area since 2002. The current study was conducted during 2009 and 2010. Flora of Mazibon and Sibon was studied along a transect from lowland to upper mountain. Three plots were made in each 100 m elevation band thus the floristic data were collected 63 plots. Totally 339 plant taxa belonging to 235 genera and 80 families were identified in the area. The Dicots with 268 taxa were the richest group of flora followed by monocots with 58 taxa, Pteridophytes with 11 taxa and Gymnosperms with 2 taxa. The variation of proportion of different life forms across the four defined altitudinal belts was surveyd. Hemicryptophytes were the dominant life form and comprised 40% of the flora. Endemism rate among 339 taxa was 4.4% (n=15 taxa. The largest proportion of the flora is related to Euro-Sibirian region (23.8% followed by Pluriregional elements (19.9%, Euro-Sibirian /Irano-Turanian (19.3%, Euro-Sibirian/Irano-Turanian/Mediterranean (16.6%.

  1. Regeneration dynamics of dominant tree species along an altitudinal gradient in moist temperate valley slopes of the Garhwal Himalaya

    Institute of Scientific and Technical Information of China (English)

    Sumeet Gairola; C.M.Sharma; S.K.Ghildiyal; Sarvesh Suyal

    2012-01-01

    The present study was undertaken in moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand,India.The aim of the present study was to understand the regeneration dynamics of the dominant tree species along an altitudinal gradient in naturally regenerating,restricted access forest.The overall regeneration status was fairly high in the study area.Most of the native canopy and undercanopy dominants had frequent reproduction and expanding populations,which suggests the stability of forest structure/composition and further expansion of dominant species.The overall regeneration of trees in the forest had a greater contribution of middle and understorey species.Because of infrequent reproduction and declining populations of some of the dominant native species viz.,Abies pindrow,Alnus nepalensis and Betula alnoides,structural/compositional changes in the future are expected in respective forests dominated by them.Abies pindrow and Taxus baccata need immediate attention by forest managers for their survival in the area.Seedlings were found to be more prone to competition from herb and shrubs than saplings.

  2. Study of Dynamics of Floodwater Nitrogen and Regulation of Its Runoff Loss in Paddy Field-Based Two-Cropping Rice with Urea and Controlled Release Nitrogen Fertilizer Application

    Institute of Scientific and Technical Information of China (English)

    JI Xiong-hui; ZHENG Sheng-xian; LU Yan-hong; LIAO Yu-lin

    2007-01-01

    The article deals with the effects of urea and controlled release nitrogen fertilizer (CRNF) on dynamics of pH, electronic conductivity (EC), total nitrogen (TN), NH4+-N and NO3--N in floodwater, and the regulation of runoff TN loss from paddy field-based two-cropping rice in Dongting Lake, China, and probes the best fertilization management for controlling N loss. Studies were conducted through modeling alluvial sandy loamy paddy soil (ASP) and purple calcareous clayey paddy soil (PCP) using lysimeter, following the sequence of the soil profiles identified by investigating soil profile. After application of urea in paddy field-based two-cropping rice, TN and NH4+-N concentrations in floodwater reached peak on the 1st and the 3rd day, respectively, and then decreased rapidly over time; all the floodwater NO3--N concentrations were very low; the pH of floodwater gradually rose in case of early rice within 15 d (late rice within 3 d) after application of urea,and EC remained consistent with the dynamics of NH4+-N. The applied CRNF, especially 70% CRNF, led to significantly lower floodwater TN and NH4+ concentrations, pH, and EC values compared with urea within 15 d after application. The monitoring result for N loss due to natural rainfall runoff indicated that the amount of TN lost in runoff from paddy fieldbased two-cropping rice with urea application in Dongting Lake area was 7.47 kg ha-1, which accounted for 2.49% of ureaN applied, and that with CRNF and 70% CRNF application decreased 24.5 and 27.2% compared with urea application,respectively. The two runoff events, which occurred within 20 d after application, contributed significantly to TN loss from paddy field. TN loss due to the two runoffs in urea, CRNF, and 70% CRNF treatments accounted for 72, 70, and 58% of the total TN loss due to runoff over the whole rice growth season, respectively. And the TN loss in these two CRNF treatments due to the first run-off event at the 10th day after application to early

  3. Hidden loss

    DEFF Research Database (Denmark)

    Kieffer-Kristensen, Rikke; Johansen, Karen Lise Gaardsvig

    2013-01-01

    to participate. RESULTS: All children were affected by their parents' ABI and the altered family situation. The children's expressions led the authors to identify six themes, including fear of losing the parent, distress and estrangement, chores and responsibilities, hidden loss, coping and support. The main......PRIMARY OBJECTIVE: The purpose of this study was to listen to and learn from children showing high levels of post-traumatic stress symptoms after parental acquired brain injury (ABI), in order to achieve an in-depth understanding of the difficulties the children face in their everyday lives...... finding indicates that the children experienced numerous losses, many of which were often suppressed or neglected by the children to protect the ill parents. CONCLUSIONS: The findings indicated that the children seemed to make a special effort to hide their feelings of loss and grief in order to protect...

  4. Experiencing Loss

    DEFF Research Database (Denmark)

    Kristiansen, Maria; Younis, Tarek; Hassani, Amani;

    2015-01-01

    In this article, we explore how Islam, minority status and refugee experiencesintersect in shaping meaning-making processes following bereavement. We do this througha phenomenological analysis of a biographical account of personal loss told by Aisha, a Muslim Palestinian refugee living in Denmark...

  5. The Effect of Altitudinal Gradient on the Carbon and Nitrogen Dynamics in Coastal Atlantic Forest of Southeast Brazil

    Science.gov (United States)

    Piccolo, M. D.; Martins, S. C.; Camargo, P. B.; Almeida, D. Q.; Correa, L. O.; Carmo, J. B.; Martinelli, L. A.

    2009-12-01

    The Brazilian Atlantic forest is a vast heterogeneous region with 1.5 million km2, encompassing a large variety of forest physiognomies and compositions, containing large number of species. These forests are distributed in different topographic and climatic conditions, with high levels of precipitation. The rate of deforestation is high, approaching 350 km2 per year, showing be highly fragmented with a large number of species in extinction. The aim of this study was to understanding of the basic biogeochemistry functioning of the coastal Atlantic Forest. The study was carried out in São Paulo State, Brazil (23° 24' S and 45° 11' W). The studied areas were: Restinga Forest at sea level; Lowland Ombrophylus Dense Forest at 100m of altitude asl; Submontana Ombrophylus Dense Forest at 400m of altitude asl and; Montane Ombrophylus Dense Forest at 1000m of altitude asl. A sampling area of 1 ha in each phytophysiognomies was subdivided in contiguous sub-parcels (10 x 10m). The forest floor litter accumulated (0.06m2) was collected monthly (n=15), during 12 months, in each phytophysiognomies. Soils samples (0-0.05m depth) were collected (n=32) from square regular grids, 30m away from each other. Techniques of multivariate like principal components analysis (PCA) were used to determine correlations between the variable. The ordination graphs make possible to observe frequent of standards, representing a significant ratio of the variability of the data. The two first PCA axes cumulatively explained 60% of the total variance of the litter variables. Litter C and δ13C values were strongly influenced by altitude at 1000m. The N and δ15N of litter were influenced by altitude at 100 and 400m. The C/N relation was influenced by altitude at 0m. The lignin was elevated (p<0.01) at sea level in comparison with the other phytophysiognomies. The cellulose values did not vary significantly along the altitudinal gradient. Soil C and N concentrations progressively increased along the

  6. Altitudinal gradients of soil and vegetation carbon and nitrogen in a high altitude nature reserve of Karakoram ranges.

    Science.gov (United States)

    Shedayi, Arshad Ali; Xu, Ming; Naseer, Iqnaa; Khan, Babar

    2016-01-01

    This study aimed to investigate the correlation of carbon and nitrogen in soil and leaves with the altitude, vegetation type, herbaceous biomass (HB), litter mass (LM) and with each other. Soil and leaf samples collected from different forest types along altitudinal gradients in the Karakoram Mountains. Dry and gas law methods were used for the chemical analysis. Regression models used for correlation analysis and T test for comparison. The correlation of soil total carbon (STC) and soil total nitrogen (STN) along altitudinal gradients and correlation between soil organic carbon (SOC) and STN was significantly positive with the values R(2) = 0.1684, p = 0.01, R(2) = 0.1537, p = 0.009 and R(2) = 0.856, p = 7.31E-10 respectively, while it was non-significant between soil inorganic carbon (SIC) and altitude and also between SIC and STN. The concentration of SOC and STN was highest in the broad leaved Betula utilis forest (22.31, 1.6 %) and least in the mixed (Pinus, Juniper, Betula) forest soil (0.85, 0.09 %) respectively. In the tree species leaf total carbon (LTC) and leaf total nitrogen (LTN) were highest in the Pinus wallichiana (PW) (632.54, 19.77), and least in the Populus alba (87.59, 4.06). In the shrub species LTC and LTN nitrogen were highest in the Rosa webiana (235.64, 7.45) and least in the Astragalus gilgitensis (43.45, 1.60) respectively. Total carbon and total nitrogen showed a slightly decreasing and increasing trend with altitude in the leaf and soil samples, respectively. The mean nitrogen and carbon was higher in the leaves of trees (3, 97.95) than in the shrubs (2.725, 74.24) and conifers (2.26, 76.46) than in the leaves of the deciduous (2, 46.36) trees. The correlation between LTC and STN was non-significant. Strong significant (R(2) = 0.608, p = 0.003) and weak non-significant (R(2) = 0.04, p = 0.32) relationships were found in STN and STC with LM and HB respectively. SOC (75.15 %) was found to be the main contributor to

  7. The contribution of radio-frequency rectification to field-aligned losses of high-harmonic fast wave power to the divertor in the National Spherical Torus eXperiment

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, R. J., E-mail: rperkins@pppl.gov; Hosea, J. C.; Jaworski, M. A.; Diallo, A.; Bell, R. E.; Bertelli, N.; Gerhardt, S.; Kramer, G. J.; LeBlanc, B. P.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Taylor, G.; Wilson, J. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Ahn, J.-W.; Gray, T. K. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); McLean, A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Sabbagh, S. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2015-04-15

    The National Spherical Torus eXperiment (NSTX) can exhibit a major loss of high-harmonic fast wave (HHFW) power along scrape-off layer (SOL) field lines passing in front of the antenna, resulting in bright and hot spirals on both the upper and lower divertor regions. One possible mechanism for this loss is RF sheaths forming at the divertors. Here, we demonstrate that swept-voltage Langmuir probe characteristics for probes under the spiral are shifted relative to those not under the spiral in a manner consistent with RF rectification. We estimate both the magnitude of the RF voltage across the sheath and the sheath heat flux transmission coefficient in the presence of the RF field. Although precise comparison between the computed heat flux and infrared (IR) thermography cannot yet be made, the computed heat deposition compares favorably with the projections from IR camera measurements. The RF sheath losses are significant and contribute substantially to the total SOL losses of HHFW power to the divertor for the cases studied. This work will guide future experimentation on NSTX-U, where a wide-angle IR camera and a dedicated set of coaxial Langmuir probes for measuring the RF sheath voltage directly will quantify the contribution of RF sheath rectification to the heat deposition from the SOL to the divertor.

  8. The contribution of radio-frequency rectification to field-aligned losses of high-harmonic fast wave power to the divertor in the National Spherical Torus eXperiment

    International Nuclear Information System (INIS)

    The National Spherical Torus eXperiment (NSTX) can exhibit a major loss of high-harmonic fast wave (HHFW) power along scrape-off layer (SOL) field lines passing in front of the antenna, resulting in bright and hot spirals on both the upper and lower divertor regions. One possible mechanism for this loss is RF sheaths forming at the divertors. Here, we demonstrate that swept-voltage Langmuir probe characteristics for probes under the spiral are shifted relative to those not under the spiral in a manner consistent with RF rectification. We estimate both the magnitude of the RF voltage across the sheath and the sheath heat flux transmission coefficient in the presence of the RF field. Although precise comparison between the computed heat flux and infrared (IR) thermography cannot yet be made, the computed heat deposition compares favorably with the projections from IR camera measurements. The RF sheath losses are significant and contribute substantially to the total SOL losses of HHFW power to the divertor for the cases studied. This work will guide future experimentation on NSTX-U, where a wide-angle IR camera and a dedicated set of coaxial Langmuir probes for measuring the RF sheath voltage directly will quantify the contribution of RF sheath rectification to the heat deposition from the SOL to the divertor

  9. Seasonal and altitudinal variations in snow algal communities on an Alaskan glacier (Gulkana glacier in the Alaska range)

    Science.gov (United States)

    Takeuchi, Nozomu

    2013-09-01

    Snow and ice algae are cold tolerant algae growing on the surface of snow and ice, and they play an important role in the carbon cycles for glaciers and snowfields in the world. Seasonal and altitudinal variations in seven major taxa of algae (green algae and cyanobacteria) were investigated on the Gulkana glacier in Alaska at six different elevations from May to September in 2001. The snow algal communities and their biomasses changed over time and elevation. Snow algae were rarely observed on the glacier in May although air temperature had been above 0 ° C since the middle of the month and surface snow had melted. In June, algae appeared in the lower areas of the glacier, where the ablation ice surface was exposed. In August, the distribution of algae was extended to the upper parts of the glacier as the snow line was elevated. In September, the glacier surface was finally covered with new winter snow, which terminated algal growth in the season. Mean algal biomass of the study sites continuously increased and reached 6.3 × 10 μl m-2 in cell volume or 13 mg carbon m-2 in September. The algal community was dominated by Chlamydomonas nivalis on the snow surface, and by Ancylonema nordenskiöldii and Mesotaenium berggrenii on the ice surface throughout the melting season. Other algae were less abundant and appeared in only a limited area of the glacier. Results in this study suggest that algae on both snow and ice surfaces significantly contribute to the net production of organic carbon on the glacier and substantially affect surface albedo of the snow and ice during the melting season.

  10. Insect responses to host plant provision beyond natural boundaries: latitudinal and altitudinal variation in a Chinese fig wasp community.

    Science.gov (United States)

    Wang, Rong; Compton, Stephen G; Quinnell, Rupert J; Peng, Yan-Qiong; Barwell, Louise; Chen, Yan

    2015-09-01

    Many plants are grown outside their natural ranges. Plantings adjacent to native ranges provide an opportunity to monitor community assembly among associated insects and their parasitoids in novel environments, to determine whether gradients in species richness emerge and to examine their consequences for host plant reproductive success. We recorded the fig wasps (Chalcidoidea) associated with a single plant resource (ovules of Ficus microcarpa) along a 1200 km transect in southwest China that extended for 1000 km beyond the tree's natural northern range margin. The fig wasps included the tree's agaonid pollinator and other species that feed on the ovules or are their parasitoids. Phytophagous fig wasps (12 species) were more numerous than parasitoids (nine species). The proportion of figs occupied by fig wasps declined with increasing latitude, as did the proportion of utilized ovules in occupied figs. Species richness, diversity, and abundance of fig wasps also significantly changed along both latitudinal and altitudinal gradients. Parasitoids declined more steeply with latitude than phytophages. Seed production declined beyond the natural northern range margin, and at high elevation, because pollinator fig wasps became rare or absent. This suggests that pollinator climatic tolerances helped limit the tree's natural distribution, although competition with another species may have excluded pollinators at the highest altitude site. Isolation by distance may prevent colonization of northern sites by some fig wasps and act in combination with direct and host-mediated climatic effects to generate gradients in community composition, with parasitoids inherently more sensitive because of declines in the abundance of potential hosts. PMID:26380693

  11. Características de la avifauna en un gradiente altitudinal de un bosque nublado andino en La Paz, Bolivia

    Directory of Open Access Journals (Sweden)

    Omar Martínez

    2013-04-01

    Full Text Available El presente trabajo analiza la diversidad y composición de la avifauna en tres localidades ubicadas dentro del Parque Nacional y Área Natural de Manejo Integrado de Cotapata, La Paz, Bolivia. Las tres localidades se distribuyeron en gradiente altitudinal y tres tipos de bosques húmedos andinos (ceja de monte a 3170 m, bosque nublado a 2620 m y bosque nublado secundario a 1850 m de la zona Yungas. Se realizó un esfuerzo total de 3286 horas-red niebla, 324 horas de caminatas y 216 horas de conteos por puntos en los tres lugares de estudio. Un total de 220 especies fueron registradas, la mayoría capturadas en redes (100 spp., 45%. Veinticinco familias fueron representadas en las capturas por redes y 42 mediante los censos. Tyrannidae y Thraupidae fueron las más representativas mediante ambos métodos. Las curvas acumulativas de especies fueron similares en todos los sitios. La riqueza de especies para la ceja de monte, bosque nublado y bosque secundario a partir de las capturas y censos fueron de 44, 40, 44 especies y 69, 57, 86 especies, respectivamente. Un total de 16 especies de rango restringido fueron registradas (p.e. Odontophorus balliviani, Andigena cucullata. La diversidad para la ceja de monte fue H´= 1,41; para el bosque nublado (H´= 0,98 y el bosque nublado secundario (H´= 0,96. La diversidad beta fue 0,74 basada en datos de capturas con redes y 0,79 basada en datos de censos en las tres alturas.

  12. Spatio-Temporal Distribution of Dengue and Lymphatic Filariasis Vectors along an Altitudinal Transect in Central Nepal

    Science.gov (United States)

    Dhimal, Meghnath; Gautam, Ishan; Kreß, Aljoscha; Müller, Ruth; Kuch, Ulrich

    2014-01-01

    Background Rapidly increasing temperatures in the mountain region of Nepal and recent reports of dengue fever and lymphatic filariasis cases from mountainous areas of central Nepal prompted us to study the spatio-temporal distribution of the vectors of these two diseases along an altitudinal transect in central Nepal. Methodology/Principal Findings We conducted a longitudinal study in four distinct physiographical regions of central Nepal from September 2011 to February 2012. We used BG-Sentinel and CDC light traps to capture adult mosquitoes. We found the geographical distribution of the dengue virus vectors Aedes aegypti and Aedes albopictus along our study transect to extend up to 1,310 m altitude in the Middle Mountain region (Kathmandu). The distribution of the lymphatic filariasis vector Culex quinquefasciatus extended up to at least 2,100 m in the High Mountain region (Dhunche). Statistical analysis showed a significant effect of the physiographical region and month of collection on the abundance of A. aegypti and C. quinquefasciatus only. BG-Sentinel traps captured significantly higher numbers of A. aegypti than CDC light traps. The meteorological factors temperature, rainfall and relative humidity had significant effects on the mean number of A. aegypti per BG-Sentinel trap. Temperature and relative humidity were significant predictors of the number of C. quinquefasciatus per CDC light trap. Dengue fever and lymphatic filariasis cases had previously been reported from all vector positive areas except Dhunche which was free of known lymphatic filariasis cases. Conclusions/Significance We conclude that dengue virus vectors have already established stable populations up to the Middle Mountains of Nepal, supporting previous studies, and report for the first time the distribution of lymphatic filariasis vectors up to the High Mountain region of this country. The findings of our study should contribute to a better planning and scaling-up of mosquito

  13. Assessing intraspecific variation in effective dispersal along an altitudinal gradient: a test in two Mediterranean high-mountain plants.

    Directory of Open Access Journals (Sweden)

    Carlos Lara-Romero

    Full Text Available BACKGROUND: Plant recruitment depends among other factors on environmental conditions and their variation at different spatial scales. Characterizing dispersal in contrasting environments may thus be necessary to understand natural intraspecific variation in the processes underlying recruitment. Silene ciliata and Armeria caespitosa are two representative species of cryophilic pastures above the tree line in Mediterranean high mountains. No explicit estimations of dispersal kernels have been made so far for these or other high-mountain plants. Such data could help to predict their dispersal and recruitment patterns in a context of changing environments under ongoing global warming. METHODS: We used an inverse modelling approach to analyse effective seed dispersal patterns in five populations of both Silene ciliata and Armeria caespitosa along an altitudinal gradient in Sierra de Guadarrama (Madrid, Spain. We considered four commonly employed two-dimensional seedling dispersal kernels exponential-power, 2Dt, WALD and log-normal. KEY RESULTS: No single kernel function provided the best fit across all populations, although estimated mean dispersal distances were short (<1 m in all cases. S. ciliata did not exhibit significant among-population variation in mean dispersal distance, whereas significant differences in mean dispersal distance were found in A. caespitosa. Both S. ciliata and A. caespitosa exhibited among-population variation in the fecundity parameter and lacked significant variation in kernel shape. CONCLUSIONS: This study illustrates the complexity of intraspecific variation in the processes underlying recruitment, showing that effective dispersal kernels can remain relatively invariant across populations within particular species, even if there are strong variations in demographic structure and/or physical environment among populations, while the invariant dispersal assumption may not hold for other species in the same environment

  14. Motivation for Weight-Loss Diets: A Clustering, Longitudinal Field Study Using Self-Esteem and Self-Determination Theory Perspectives

    Science.gov (United States)

    Georgiadis, Manolis M.; Biddle, Stuart J. H.; Stavrou, Nektarios A.

    2006-01-01

    Background: Gradual elevation of body weight leads numerous individuals to dieting and weight loss behaviours. Nevertheless, the prevalence of obesity continues to rise in industrialised countries. The examination of the motivational determinants of dietary modification ("dieting") in order to identify clusters of individuals in the first 6 months…

  15. Large-scale fungal diversity assessment in the Andean Yungas forests reveals strong community turnover among forest types along an altitudinal gradient.

    Science.gov (United States)

    Geml, József; Pastor, Nicolás; Fernandez, Lisandro; Pacheco, Silvia; Semenova, Tatiana A; Becerra, Alejandra G; Wicaksono, Christian Y; Nouhra, Eduardo R

    2014-05-01

    The Yungas, a system of tropical and subtropical montane forests on the eastern slopes of the Andes, are extremely diverse and severely threatened by anthropogenic pressure and climate change. Previous mycological works focused on macrofungi (e.g. agarics, polypores) and mycorrhizae in Alnus acuminata forests, while fungal diversity in other parts of the Yungas has remained mostly unexplored. We carried out Ion Torrent sequencing of ITS2 rDNA from soil samples taken at 24 sites along the entire latitudinal extent of the Yungas in Argentina. The sampled sites represent the three altitudinal forest types: the piedmont (400-700 m a.s.l.), montane (700-1500 m a.s.l.) and montane cloud (1500-3000 m a.s.l.) forests. The deep sequence data presented here (i.e. 4 108 126 quality-filtered sequences) indicate that fungal community composition correlates most strongly with elevation, with many fungi showing preference for a certain altitudinal forest type. For example, ectomycorrhizal and root endophytic fungi were most diverse in the montane cloud forests, particularly at sites dominated by Alnus acuminata, while the diversity values of various saprobic groups were highest at lower elevations. Despite the strong altitudinal community turnover, fungal diversity was comparable across the different zonal forest types. Besides elevation, soil pH, N, P, and organic matter contents correlated with fungal community structure as well, although most of these variables were co-correlated with elevation. Our data provide an unprecedented insight into the high diversity and spatial distribution of fungi in the Yungas forests. PMID:24762095

  16. Diversidad y distribución de la fauna quiroptera en un transecto altitudinal en el departamento del tolima,colombia

    OpenAIRE

    BEJARANO-BONILLA, DAVID ALFONSO; YATE-RIVAS, ALEXANDER; BERNAL-BAUTISTA, MANUEL HERNANDO

    2012-01-01

    Se estudió la diversidad y la distribución de la quiroterofauna registrada sobreun sector de la vertiente Oriental de la cordillera Central en el departamento delTolima, en un transecto altitudinal dividido en cuatro zonas de muestreo (I: 350-1000; II: 1000-2000; III: 2000-3000 y IV: 3000-4000). Se encontraron 42 especiescorrespondientes a 21 géneros y cuatro familias. La familia Phyllostomidae fuelas más diversa y abundante, con 34 especies y 92.5% del número de individuoscolectados. Por su ...

  17. Warming effects on photosynthesis of subtropical tree species: a translocation experiment along an altitudinal gradient.

    Science.gov (United States)

    Li, Yiyong; Liu, Juxiu; Zhou, Guoyi; Huang, Wenjuan; Duan, Honglang

    2016-01-01

    Ongoing climate warming induced by human activities may have great impacts on trees, yet it remains unresolved how subtropical tree species respond to rising temperature in the field. Here, we used downward translocation to investigate the effects of climate warming on leaf photosynthesis of six common tree species in subtropical China. During the experimental period between 2012 and 2014, the mean average photosynthetic rates (Asat) under saturating light for Schima superba, Machilus breviflora, Pinus massoniana and Ardisia lindleyana in the warm site were7%, 19%, 20% and 29% higher than those in the control site. In contrast, seasonal Asat for Castanopsis hystrix in the warm site were lower compared to the control site. Changes in Asat in response to translocation were mainly associated with those in leaf stomatal conductance (gs) and photosynthetic capacity (RuBP carboxylation, RuBP regeneration capacity). Our results imply that climate warming could have potential impacts on species composition and community structure in subtropical forests. PMID:27102064

  18. Limits of life across an altitudinal gradient ina Tropical Dormant Volcano

    Science.gov (United States)

    Molina-Sevilla, P.; Lonzano-Ramírez, C.; Navarro-González, R.; Callegan, R.; Rainey, F. A.; Cruz-Kuri, L.; McKay, C. P.

    2008-09-01

    Abstract The most recent missions to Mars have the aim to confirm if life once existed on the planet. In case of no life vestiges found, it exist the possibility of return Mars to ancient conditions when life possibly thrived. The greenhouse gasses releasing it could be necessary in order to raise the temperature, as a result of this change; the water actually trapped into the Martian regolith will be in liquid state again, the atmosphere will became thicker. It has been thought this process could be 100 000 years long. However, during this planetary experiment only a few of microorganisms and invertebrates could survive, the high levels of CO2 and a still thin atmosphere are uphill struggle [1,2]. It is known that some superior plants are capable of survival in similar environmental conditions we expect in a terraformed mars. These type of plants as well as cyanobacteria could reduce the high CO2 levels and produce O2 doing of Mars an habitable place for living [3]. One of the most interesting places on the Earth is the volcano Pico de Orizaba in Mexico; here the wood grows at the highest altitude above sea level on the world. Pinus hartwegii is the only species of tree thriving at this altitude, about 4400 m. In this place the environmental conditions are extremely arduous. At the moment we have evaluated some physical (density, porosity, texture) and chemical (exchangeable bases, cationic exchangeable capacity) properties of soil in order to know if exists some special condition for thriving of P. hartwegii wood. Results According to elemental analysis tests we have found the organic matter in forest soil, just at the timberline has around 5% of organic carbon, meanwhile the grater the high the lesser organic carbon, less than 1%. C/N ratio is ~18 for lower zones, something characteristic for forest soils, above timberline the ratio decreases to values between 10 and 7, this is a carbon loss due to mineralization. Hydraulic conductivity was measured in order to

  19. SOM storage and pool distribution in forest soils along climatic and altitudinal gradients across Switzerland

    Science.gov (United States)

    Gosheva, Sia; Müller, Mirjam; Walthert, Lorenz; Zimmermann, Stephan; Niklaus, Pascal A.; González Domínguez, Beatriz R.; Abiven, Samuel; Hagedorn, Frank

    2016-04-01

    stocks in the organic layer, we observed a positive relationship with elevation and a negative one with MAT. Linear regression analysis indicated SOC stocks in the organic layer to decrease by over 60% with an increase in MAT by 5°C. In the mineral soil, MAT and elevation had no effect; however, SOC stocks correlated positively with MAP. The elevational changes occurred on both calcareous and acidic bedrock. Similarly to the organic layer, we found an increase in POM-fractions with an increasing elevation and MAP but not for mOM. In particular, MAP seems important for the POM in the mineral soil, while MAT affects the organic layer. Consequently, a warmer and drier climate could lead to a deterioration of SOM, especially at high elevations. This could possibly cause a redistribution of carbon pools and C losses from forest soils.

  20. A new species of Anacroneuria Klapálek 1909 (Plecoptera: Perlidae) and notes on the altitudinal distribution of the genus in Costa Rica.

    Science.gov (United States)

    Gutiérrez-Fonseca, Pablo E; Springer, Monika

    2015-12-18

    Anacroneuria is the most widespread genus of Perlidae throughout the Neotropical region and 30 species have been reported from Costa Rica. In this paper, we describe and illustrate a new species from a high elevation cloud forest, A. quetzali sp.n., increasing to 31 the number of described species for Costa Rica. In addition, we examine the altitudinal distribution of Anacroneuria in Costa Rica to determine possible patterns, using the data available on its altitudinal range (10-2700 masl). We divided the elevational range in seven categories, using 500 m intervals. We found that most species (90.3%) are distributed in elevations that range from 500 to 1500 masl, followed by low-elevations (35.5%). Interestingly, despite the fact that Plecoptera are known to inhabit clean, fast flowing water at high elevations, only 16.1% of the species have been found at high elevations in Costa Rica (above 2000 masl). Thus, it seems that most Anacroneuria species are distributed in middle elevations, which are the areas that have a high diversity of freshwater habitats.

  1. Pattern of NDVI-based vegetation greening along an altitudinal gradient in the eastern Himalayas and its response to global warming.

    Science.gov (United States)

    Li, Haidong; Jiang, Jiang; Chen, Bin; Li, Yingkui; Xu, Yuyue; Shen, Weishou

    2016-03-01

    The eastern Himalayas, especially the Yarlung Zangbo Grand Canyon Nature Reserve (YNR), is a global hotspot of biodiversity because of a wide variety of climatic conditions and elevations ranging from 500 to > 7000 m above sea level (a.s.l.). The mountain ecosystems at different elevations are vulnerable to climate change; however, there has been little research into the patterns of vegetation greening and their response to global warming. The objective of this paper is to examine the pattern of vegetation greening in different altitudinal zones in the YNR and its relationship with vegetation types and climatic factors. Specifically, the inter-annual change of the normalized difference vegetation index (NDVI) and its variation along altitudinal gradient between 1999 and 2013 was investigated using SPOT-VGT NDVI data and ASTER global digital elevation model (GDEM) data. We found that annual NDVI increased by 17.58% in the YNR from 1999 to 2013, especially in regions dominated by broad-leaved and coniferous forests at lower elevations. The vegetation greening rate decreased significantly as elevation increased, with a threshold elevation of approximately 3000 m. Rising temperature played a dominant role in driving the increase in NDVI, while precipitation has no statistical relationship with changes in NDVI in this region. This study provides useful information to develop an integrated management and conservation plan for climate change adaptation and promote biodiversity conservation in the YNR.

  2. 泉州市鸟类多样性海拔梯度格局的研究%Study on altitudinal patterns of avian diversity in Quanzhou city

    Institute of Scientific and Technical Information of China (English)

    何中声; 刘金福; 洪伟; 杨文晖; 付达靓; 郑世群

    2012-01-01

    A survey of the species and population sizes of birds was conducted alone with altitudinal gradients patterns in Quanzhou city, Fujian, Southern China and then the affection of altitudinal gradients to the avian diversity was analyzed. The results show that a species diversity of avian was the highest at the elevations between 500 m and 1000 m, increased at first and then decreased along with altitudinal gradients which showed a single peak curve in accordance with the theory of middle domain effect. The bird' s indices of a species diversity were the highest at the elevations between 500 m and 1000 m. The P species diversity of avian were relatively high at from altitude 500 m-1000 m to 1000 m-1250 m and from 50 m-200 m to 200 m-S00 m which showed that the bird species changed dramatically across altitudes. Meanwhile, the similarity indices of Jaccrad index and Sorenson index further revealed that avian diversity was highly sensitive in altitudes from 500 m-1000 m to 1000 m-1250 m and from 50 m-200 m to 200 m-500 m was the sensitive area of bird species diversity. Avian diversity at the genus and family level increased firstly and then decreased along with altitudinal gradients in accordance with avian a species diversity apd was the highest at the elevations between 500 m and 1000 m. The study indicated that the climate conditions, vegetation types and the degree of human disturbance were the main factors that affected the bird species diversity along with altitudinal gradients which could provide a scientific basis for conserving and monitoring avian biodiversity in Quanzhou city.%对栖息于泉州市不同海拔梯度鸟类种类和数量进行了调查,分析了海拔梯度格局对鸟类物种多样性的影响.结果表明:泉州市鸟类α物种多样性指数沿海拔梯度基本呈先升高后降低的“单峰型”曲线,与“中间膨胀”理论相符合,在500~1000 m海拔段均最大.在500~1250 m海拔段和50~500m海拔段中鸟类β多

  3. Multi-source analysis reveals latitudinal and altitudinal shifts in range of Ixodes ricinus at its northern distribution limit

    Directory of Open Access Journals (Sweden)

    Kristoffersen Anja B

    2011-05-01

    Full Text Available Abstract Background There is increasing evidence for a latitudinal and altitudinal shift in the distribution range of Ixodes ricinus. The reported incidence of tick-borne disease in humans is on the rise in many European countries and has raised political concern and attracted media attention. It is disputed which factors are responsible for these trends, though many ascribe shifts in distribution range to climate changes. Any possible climate effect would be most easily noticeable close to the tick's geographical distribution limits. In Norway- being the northern limit of this species in Europe- no documentation of changes in range has been published. The objectives of this study were to describe the distribution of I. ricinus in Norway and to evaluate if any range shifts have occurred relative to historical descriptions. Methods Multiple data sources - such as tick-sighting reports from veterinarians, hunters, and the general public - and surveillance of human and animal tick-borne diseases were compared to describe the present distribution of I. ricinus in Norway. Correlation between data sources and visual comparison of maps revealed spatial consistency. In order to identify the main spatial pattern of tick abundance, a principal component analysis (PCA was used to obtain a weighted mean of four data sources. The weighted mean explained 67% of the variation of the data sources covering Norway's 430 municipalities and was used to depict the present distribution of I. ricinus. To evaluate if any geographical range shift has occurred in recent decades, the present distribution was compared to historical data from 1943 and 1983. Results Tick-borne disease and/or observations of I. ricinus was reported in municipalities up to an altitude of 583 metres above sea level (MASL and is now present in coastal municipalities north to approximately 69°N. Conclusion I. ricinus is currently found further north and at higher altitudes than described in

  4. Free-solution electrophoretic separations of DNA-drag-tag conjugates on glass microchips with no polymer network and no loss of resolution at increased electric field strength.

    Science.gov (United States)

    Albrecht, Jennifer Coyne; Kerby, Matthew B; Niedringhaus, Thomas P; Lin, Jennifer S; Wang, Xiaoxiao; Barron, Annelise E

    2011-05-01

    Here, we demonstrate the potential for high-resolution electrophoretic separations of ssDNA-protein conjugates in borosilicate glass microfluidic chips, with no sieving media and excellent repeatability. Using polynucleotides of two different lengths conjugated to moderately cationic protein polymer drag-tags, we measured separation efficiency as a function of applied electric field. In excellent agreement with prior theoretical predictions of Slater et al., resolution is found to remain constant as applied field is increased up to 700 V/cm, the highest field we were able to apply. This remarkable result illustrates the fundamentally different physical limitations of free-solution conjugate electrophoresis (FSCE)-based DNA separations relative to matrix-based DNA electrophoresis. ssDNA separations in "gels" have always shown rapidly declining resolution as the field strength is increased; this is especially true for ssDNA > 400 bases in length. FSCE's ability to decouple DNA peak resolution from applied electric field suggests the future possibility of ultra-rapid FSCE sequencing on chips. We investigated sources of peak broadening for FSCE separations on borosilicate glass microchips, using six different protein polymer drag-tags. For drag-tags with four or more positive charges, electrostatic and adsorptive interactions with poly(N-hydroxyethylacrylamide)-coated microchannel walls led to appreciable band-broadening, while much sharper peaks were seen for bioconjugates with nearly charge-neutral protein drag-tags.

  5. ESTRUCTURA DE UNA COMUNIDAD DE LÍQUENES Y MORFOLOGIA DEL GÉNERO STICTA (STICTACEAE EN UN GRADIENTE ALTITUDINAL

    Directory of Open Access Journals (Sweden)

    Perez Quintero Alvaro Luis

    2009-12-01

    -pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

    La distribución y el crecimiento de los líquenes están condicionados por diferentes factores ambientales, entre estos la variación en gradientes altitudinales. En la cordillera Oriental de los Andes de Colombia, no se han realizado estudios sobre zonación altitudinal de líquenes. En este trabajo se estudiaron las variaciones en la estructura de la comunidad de líquenes epifitos en un gradiente altitudinal (2000-2600 m en el PNN Tatamá. Se encontró que con el aumento en altura hay una disminución en riqueza y diversidad, siendo esto una desviación del patrón encontrado generalmente en otros trabajos sobre líquenes y gradientes altitudinales. La comunidad a bajas alturas se compone principalmente de líquenes fruticosos (cobertura de 30% a 2070 m y 0% a 2560 m y a mayores alturas de líquenes foliosos (cobertura de 15% a 2070 m y 43% a 2560 m. La altura, además de influenciar la estructura de la comunidad de los líquenes, puede afectar el desarrollo y la morfología de estos. En el género folioso Sticta se presentaron variaciones intraespecificas en la densidad de cifelas (órganos de intercambio gaseoso asociadas a la altura, encontrándose un efecto significativo de la altura sobre la densidad de cifelas en las especies S. andensis  y S. gyalocarpa (ANOVA, valor p= 0.008 y 0.05 respectivamente. Esto muestra un mecanismo de adaptación a los cambios ambientales que se dan con la altura.

  6. The novel fluid loss additive HTF-200C for oil field cementing%新型固井降失水剂HTF-200C

    Institute of Scientific and Technical Information of China (English)

    郭锦棠; 卢海川; 刘硕琼; 靳建州; 于永金

    2012-01-01

    The domestic fluid loss additives often have lower thermal stability and poor salt-tolerance and their comprehensive properties are not good enough. To solve the problems, a novel cement fluid loss additive HTF-200C. Which can resist high temperature and high salt content, was synthesized using the monomers of 2-acrylamido-2-methyl-propane sulphonic acid (AMPS), N, N-dimethyl acrylamide (DMAA) and a new compound with double carboxyl by the method of aqueous solution polymerization. The microstructural characterization and application performance of HTF-200C show that the polymer with the structure of all the monomers has an excellent thermal stability and strong salt tolerance, and can be used in 200 "C or in saturated brine. And the problem of the normal fluid loss additive being easy to hydrolyze due to high temperature can be solved with HTF-200C. What's more, it can also deal with the bulge of thickening curve in consistency test. The cement slurry prepared mainly by HTF-200C presents good comprehensive properties such as low filtration, high thermal stability, strong salt tolerance, rapid development of strength in low temperature, without far delayed solidification, short transit time during thickening process, and so on. The cementing job quality of Well Chengu 1-3 in the Liaohe Oilfield is excellent after it is used.%针对目前中国常规固井降失水剂抗温抗盐能力差、综合性能欠佳的问题,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、N,N-二甲基丙烯酰胺(DMAA)、新型双羧基化合物为单体,采用水溶液自由基聚合的方法合成了耐盐、抗高温的共聚物型固井水泥降失水剂HTF-200C.HTF-200C微观结构表征和应用性能综合评价表明,各单体成功参与聚合,共聚物热稳定性良好;该降失水剂控失水耐温可达200℃,抗盐达饱和,可解决常规降失水剂高温下易水解、稠化实验“鼓包”等问题;以HTF-200C为主剂的水泥浆体系失水量低、抗盐耐温

  7. 基于多源信息的区域尺度山地植被带数字化提取%Modeling the Spatial Distribution of Altitudinal Vegetation Belts Based on Multi-source Data

    Institute of Scientific and Technical Information of China (English)

    孙然好; 张百平; 许娟

    2011-01-01

    In mountain areas, an altitudinal vegetation belt ( AVB ) is the most stable vegetation cover according to the climatic conditions as altitude increases, and it represents the climatic climax community. Investigation and I-dentification of AVBs is significant in ecological and geographical studies thanks to extremely complex environment and diverse vegetation types in mountains. Traditionally, field survey only produced discrete data, and AVBs and their vertical combination are mainly expressed as hand-drawn diagrams. This seriously restricted quantitative analysis of AVBs and their spatial patterns. We present a method for predictive vegetation mapping in the Daqing Mountains of central Inner Mongolia of China. Firstly, we obtain the representative vegetation samples using 1: 250 000 DEM, 1: 1 000 000 vegetation map, 1: 100 000 land-use map and related references. According to the relationship of the vegetation samples and the environmental variables affecting them, we simulate the potential distribution of vegetations by using the Bayes algorithm under the software of ERDAS. Tested by the selected 3 000 grids, the whole accuracy of the mapping is 74. 53 % and the Kappa coefficient is 0.69. The research of potential climax vegetation provides a comparative data source, and the comparison of existing and potential altitudinal patterns is also an interesting issue in geographical and ecological studies. The method makes identifying and comparing AVBs considerably easier by using multi-source data, and could potentially be a solid basis for in-depth analysis of AVBs with their environmental factors.%山地植被带的提取及分析是地学和生态学研究的基础问题之一.利用野外点/线调查和历史文献资料,可以对局域尺度山体的植被带进行归纳和描绘,而在区域乃至全球尺度上更多依赖于学者的经验和知识.利用内蒙古大青山地区1∶100万植被图、1∶10万土地利用图、1∶25万DEM等,设计逻辑判

  8. Missing data in randomized clinical trials for weight loss: scope of the problem, state of the field, and performance of statistical methods.

    Directory of Open Access Journals (Sweden)

    Mai A Elobeid

    Full Text Available BACKGROUND: Dropouts and missing data are nearly-ubiquitous in obesity randomized controlled trails, threatening validity and generalizability of conclusions. Herein, we meta-analytically evaluate the extent of missing data, the frequency with which various analytic methods are employed to accommodate dropouts, and the performance of multiple statistical methods. METHODOLOGY/PRINCIPAL FINDINGS: We searched PubMed and Cochrane databases (2000-2006 for articles published in English and manually searched bibliographic references. Articles of pharmaceutical randomized controlled trials with weight loss or weight gain prevention as major endpoints were included. Two authors independently reviewed each publication for inclusion. 121 articles met the inclusion criteria. Two authors independently extracted treatment, sample size, drop-out rates, study duration, and statistical method used to handle missing data from all articles and resolved disagreements by consensus. In the meta-analysis, drop-out rates were substantial with the survival (non-dropout rates being approximated by an exponential decay curve (e(-lambdat where lambda was estimated to be .0088 (95% bootstrap confidence interval: .0076 to .0100 and t represents time in weeks. The estimated drop-out rate at 1 year was 37%. Most studies used last observation carried forward as the primary analytic method to handle missing data. We also obtained 12 raw obesity randomized controlled trial datasets for empirical analyses. Analyses of raw randomized controlled trial data suggested that both mixed models and multiple imputation performed well, but that multiple imputation may be more robust when missing data are extensive. CONCLUSION/SIGNIFICANCE: Our analysis offers an equation for predictions of dropout rates useful for future study planning. Our raw data analyses suggests that multiple imputation is better than other methods for handling missing data in obesity randomized controlled trials

  9. Effect of Diffraction Loss of Optical Parametric Oscillator on Its Output Field%光学参量振荡器衍射损耗对输出场的影响

    Institute of Scientific and Technical Information of China (English)

    王东; 黄仙山

    2012-01-01

    损耗对量子态的压缩和纠缠特性有重要影响.当光学参量振荡器微型化时,衍射损耗可能会降低光场的压缩度.针对菲涅尔数较小的平凹谐振腔,将菲涅尔—基尔霍夫衍射积分方程变量分离,利用Fox-Li数值迭代法分析平凹腔的镜面场分布和损耗特性.结果表明迭代法得到的自再现模不同于ABCD矩阵法得到的高斯模,但是二者相差不大;当镜片尺寸继续减小时,会使得镜面不再是等相位面,镜面上的位相呈高斯分布,因此会影响光学参量振荡器输出场的压缩度和关联度.%Loss has important impact on properties of squeezing and entanglement of quantum state. In the miniaturization of optical parametric oscillator, diffraction loss may be the main reason of reducing the squeezing degree. For a plano-concave resonator with small Fresnel number, the field distribution and loss are calculated by separating the variables of Fresnel-Kirchhoff integral equation with numerical iteration method. Results show that the normal mode obtained with the iterative method differs from that of the Gaussian mode obtained from ABCD matrix, but there is small difference. Decreasing the size of the len, the mirror is no longer the equiphase surface, and the phase on the mirror presents as Gaussian distribution, that affects the squeezing and correlation degree of the output field of the optical parametric oscillator.

  10. Integrating the EMPD with an Alpine altitudinal training set to reconstruct climate variables in Holocene pollen records from high-altitude peat bogs

    Science.gov (United States)

    Furlanetto, Giulia; Badino, Federica; Brunetti, Michele; Champvillair, Elena; De Amicis, Mattia; Maggi, Valter; Pini, Roberta; Ravazzi, Cesare; Vallé, Francesca

    2016-04-01

    Temperatures and precipitation are the main environmental factors influencing vegetation and pollen production. Knowing the modern climate optima and tolerances of those plants represented in fossil assemblages and assuming that the relationships between plants and climate in the past are not dissimilar from the modern ones, fossil pollen records offer many descriptors to reconstruct past climate variables. The aim of our work is to investigate the potential of high-altitude pollen records from an Alpine peat bog (TBValter, close to the Ruitor Glacier, Western Italian Alps) for quantitative paleoclimate estimates. The idea behind is that high-altitude ecosystems are more sensitive to climate changes, especially to changes in July temperatures that severely affect the timberline ecotone. Meantime, we met with difficulties when considering the factors involved in pollen dispersal over a complex altitudinal mountain pattern, such as the Alps. We used the EMPD-European Modern Pollen Database (Davis et al., 2013) as modern training set to be compared with our high-altitude fossil site. The EMPD dataset is valuable in that it provides a large geographic coverage of main ecological and climate gradients (at sub-continental scale) but lacks in sampling of altitudinal gradients and high-altitude sites in the Alps. We therefore designed an independent altitudinal training set for the alpine valley hosting our fossil site. 27 sampling plots were selected along a 1700m-elevational transect. In a first step, each plot was provided with (i) 3 moss polsters collected following the guidelines provided by Cañellas-Boltà et al. (2009) and analyzed separately to account for differences in pollen deposition at small scale, (ii) morphometrical parameters obtained through a high-resolution DEM, and (iii) temperature and precipitation were estimated by means of weighted linear regression of the meteorological variable versus elevation, locally evaluated for each site (Brunetti et al

  11. Patrones de dispersión de semillas por aves en perchas en un gradiente altitudinal con alteración antrópica

    Directory of Open Access Journals (Sweden)

    Vargas Rincón Carlos Alberto

    2006-06-01

    Full Text Available En tres sitios ubicados en un gradiente altitudinal de bosque altoandino sometido a disturbio antrópico, se estudiaron patrones de arribo de semillas dispersadas por aves a perchas en áreas abiertas. Se logró determinar que el arribo de semillas a estas estructuras está relacionado con el grado de fragmentación del bosque, así como tambien de la diversidad de los parches de bosque aledaños. La especie de ave que más frecuentó las perchas fue Turdus fuscater, debido a que es una especie que vuela en campo abierto. Además, que al ser una especie altamente omnivora es capaz de promover la llegada a las perchas de semillas de diferentes especies.

  12. An H-formulation-based three-dimensional hysteresis loss modelling tool in a simulation including time varying applied field and transport current: the fundamental problem and its solution

    International Nuclear Information System (INIS)

    When analytic solutions are not available, finite-element-based tools can be used to simulate hysteresis losses in superconductors with various shapes. A widely used tool for the corresponding magnetoquasistatic problem is based on the H-formulation, where H is the magnetic field intensity, eddy current model. In this paper, we study this type of tool in a three-dimensional simulation problem. We consider a case where we simultaneously apply both a time-varying external magnetic field and a transport current to a twisted wire. We show how the modelling decisions (air has high finite resistivity and applied field determines the boundary condition) affect the current density distribution along the wire. According to the results, the wire carries the imposed net current only on the boundary of the modelling domain, but not inside it. The current diffuses to the air and back to the boundary. To fix this problem, we present another formulation where air is treated as a region with 0 conductivity. Correspondingly, we express H in the air with a scalar potential and a cohomology basis function which considers the net current condition. As shown in this paper, this formulation does not fail in these so-called AC-AC (time varying transport current and applied magnetic field) simulations. (paper)

  13. Altitudinal patterns of the lichen genus Cladonia (Lichenized Ascomycota) in China%中国石蕊属地衣的垂直分布规律

    Institute of Scientific and Technical Information of China (English)

    郭守玉; 邓红; 毕海燕; 夏晓飞; 黄满荣

    2013-01-01

    Altitudinal patterns of the lichen genus Cladonia and 18 species in the genus were investigated based on herbarium collections.Species in the genus are inclined to grow at high elevation.Normal and lognormal probability patterns are ubiquitous for vertical distribution of these species,and vertical patterns are somewhat elevation-dependent.The altitudinal ranges of the species were found to decrease with increase of altitude.These evidences suggest an immediate threat from global warming to some species growing at higher elevation in the genus.Ecological evidence also confirms C.bacillaris and C.macilenta are conspecific.%基于标本馆馆藏标本的信息,研究了中国石蕊属Cladonia地衣及其18个种的垂直分布规律,并确认了本属倾向于分布在高海拔地区的特点.物种随海拔梯度的变化在统计学上呈正态分布或偏正态分布是非常普遍的现象,但是它们的分布规律与其所处的海拔位置相关:物种分布范围随着海拔的增加而缩小.因此,全球变暖会对高海拔地区的物种构成更直接的威胁.粉杆石蕊C.bacillaris和瘦柄红石蕊C.macilenta具有相同的海拔分布规律和分布范围,从生态学的角度支持了它们为同种的观点.

  14. Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

    Science.gov (United States)

    Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

    2012-12-01

    This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients

  15. Vision Loss, Sudden

    Science.gov (United States)

    ... of age-related macular degeneration. Spotlight on Aging: Vision Loss in Older People Most commonly, vision loss ... Some Causes and Features of Sudden Loss of Vision Cause Common Features* Tests Sudden loss of vision ...

  16. Coupled field finite element analysis for turbine generator under loss-of-excitation asynchronous operation%汽轮发电机失磁异步运行的耦合场有限元分析

    Institute of Scientific and Technical Information of China (English)

    高慧; 姚缨英

    2011-01-01

    为了准确模拟汽轮发电机失磁故障发生后的运行状态,建立了场、路、运动直接耦合的时步有限元分析模型,把电机的电磁场方程和定转子的等效电路方程进行联立求解,得到失磁故障过程中定子端电压、定子电流、转速、有功功率等变量随时间变化的波形,以及转子中涡流场的分布;通过间接耦合实现了失磁过程中转子的温度场计算.对1000 MW汽轮发电机励磁绕组失磁进行了时步有限元分析,并通过转子温升计算和有功、无功功率波动结果可知:汽轮发电机失磁后,转差率、有功功率及转子铁心温度均在限定值内,但定子电流值过大,应采取及时的保护措施.%To accurately simulate the operating characteristics of turbine generator after loss of excitation, this work established a field-circuit-motion coupled time stepping finite element model, solved the electro-magnetic field equations and the equivalent circuit equations in the stator and rotor windings, obtained the wareforms of the stator terminal voltage, stator current, speed, active power and other variables after loss of excitation, as well as the distribution of rotor eddy current; and achieved the temperature distributed in the rotor through indirect magnetic-thermal coupling model. A 1 000 MW turbine generator running under entire short-circuit loss of excitation and entire open-circuit loss of excitation were calculated respectively. The results of the rotor temperature rise as well as the fluctuations of active power and reactive power show that the slip, active power and rotor temperature are within the limited values, but the stator current is too large, so protective measures should be taken timely.

  17. Maternal exposure to a continuous 900-MHz electromagnetic field provokes neuronal loss and pathological changes in cerebellum of 32-day-old female rat offspring.

    Science.gov (United States)

    Odacı, Ersan; Hancı, Hatice; İkinci, Ayşe; Sönmez, Osman Fikret; Aslan, Ali; Şahin, Arzu; Kaya, Haydar; Çolakoğlu, Serdar; Baş, Orhan

    2016-09-01

    Large numbers of people are unknowingly exposed to electromagnetic fields (EMF) from wireless devices. Evidence exists for altered cerebellar development in association with prenatal exposure to EMF. However, insufficient information is still available regarding the effects of exposure to 900 megahertz (MHz) EMF during the prenatal period on subsequent postnatal cerebellar development. This study was planned to investigate the 32-day-old female rat pup cerebellum following exposure to 900MHz EMF during the prenatal period using stereological and histopathological evaluation methods. Pregnant rats were divided into control, sham and EMF groups. Pregnant EMF group (PEMFG) rats were exposed to 900MHz EMF for 1h inside an EMF cage during days 13-21 of pregnancy. Pregnant sham group (PSG) rats were also placed inside the EMF cage during days 13-21 of pregnancy for 1h, but were not exposed to any EMF. No procedure was performed on the pregnant control group (PCG) rats. Newborn control group (CG) rats were obtained from the PCG mothers, newborn sham group (SG) rats from the PSG and newborn EMF group (EMFG) rats from the PEMFG rats. The cerebellums of the newborn female rats were extracted on postnatal day 32. The number of Purkinje cells was estimated stereologically, and histopathological evaluations were also performed on cerebellar sections. Total Purkinje cell numbers calculated using stereological analysis were significantly lower in EMFG compared to CG (pprenatal exposure to EMF affects the development of Purkinje cells in the female rat cerebellum and that the consequences of this pathological effect persist after the postnatal period. PMID:26391347

  18. Distribuição altitudinal e sazonal de afídeos (Hemiptera, Aphididae na Serra do Mar, Paraná, Brasil

    Directory of Open Access Journals (Sweden)

    Sonia M. N. Lazzari

    2005-12-01

    Full Text Available Dentre as 130 espécies de afídeos registradas para o Brasil, a maioria é exótica com origem em regiões temperadas. O objetivo desta pesquisa foi o estudo das espécies de afídeos que ocorrem em diferentes altitudes no ecossistema rico em diversidade da Mata Atlântica. Onze pontos de coleta foram amostrados em um gradiente altitudinal de -10 a 1000 m s.n.m. na Serra do Mar, no estado do Paraná com armadilhas amarelas de água e coletas nas plantas no decorrer de um ano. Um total de 87 espécies de afídeos foi coletado em armadilhas e em plantas. O maior número de espécies foi encontrado em áreas de transição ou ecótone definidos pela sobreposição de comunidades diferentes de plantas. Aphis spiraecola Patch, 1914 foi a espécie mais abundante registrada em todos os locais amostrados. O pico populacional ocorreu, principalmente, no mês de setembro quando as plantas estavam em brotação. Não foi observado um padrão altitudinal na distribuição dos afídeos na Serra do Mar, porém algumas espécies foram registradas em altitudes específicas. Condições climáticas, além de outros fatores bióticos e abióticos, afetam a flutuação populacional dos afídeos, porém não foi possível estabelecer uma correlação entre a ocorrência dos insetos com a temperatura e precipitação.There are about 130 species of aphids registered for Brazil and most of them are exotic, originated from temperate regions. The objective of this research was to survey the aphid species that occur in different altitudes in the rich and diverse ecosystem of the Atlantic Rain Forest. The area surveyed included 11 collecting points ranging from -10 to 1000 m a.s.l. in Serra do Mar, in Paraná State, using yellow pan traps and plant collection, during one year. A total of 87 aphid species were collected in the traps and plants. The richness of species was noticeable high in transitional areas, where different plant communities overlapped. The most

  19. Living with vision loss

    Science.gov (United States)

    Diabetes - vision loss; Retinopathy - vision loss; Low vision; Blindness - vision loss ... Low vision is a visual disability. Wearing regular glasses or contacts does not help. People with low vision have ...

  20. Economic Loan Loss Provision and Expected Loss

    Directory of Open Access Journals (Sweden)

    Stefan Hlawatsch

    2010-10-01

    Full Text Available The intention of a loan loss provision is the anticipation of the loan's expected losses by adjusting the book value of the loan. Furthermore, this loan loss provision has to be compared to the expected loss according to Basel II and, in the case of a difference, liable equity has to be adjusted. This however assumes that the loan loss provision and the expected loss are based on a similar economic rationale, which is only valid conditionally in current loan loss provisioning methods according to IFRS. Therefore, differences between loan loss provisions and expected losses should only result from different approaches regarding the parameter estimation within each model and not due to different assumptions regarding the outcome of the model. The provisioning and accounting model developed in this paper overcomes the before-mentioned shortcomings and is consistent with an economic rationale of expected losses. Additionally, this model is based on a close-to-market valuation of the loan that is in favor of the basic idea of IFRS. Suggestions for changes in current accounting and capital requirement rules are provided.

  1. Ampliación del ámbito geográfico-altitudinal y uso de hábitats suburbanos por la mascarita pico grueso (Geothlypis poliocephala Geographic-altitudinal range extension and suburban habitat use of the Grey-crowned Yellowthroat (Geothlypis poliocephala

    Directory of Open Access Journals (Sweden)

    Ian MacGregor-Fors

    2008-12-01

    Full Text Available Se presenta el primer registro de la mascarita pico grueso (Geothlypis poliocephala para la región del Eje Neovolcánico Transversal, México. Los sitios donde registramos/capturamos esta especie se encuentran en los suburbios de la ciudad de Morelia, 427 m arriba del ámbito altitudinal descrito para la especie. Esto puede deberse a 2 factores: 1 la urbanización que genera hábitats propicios para la especie en su periferia, y 2 el incremento de la temperatura en la región en la que se encuentra la ciudad de Morelia. Ambos factores facilitan que esta especie de tierras bajas pueda habitar en áreas de mayor altitud. Así, nuestros registros sugieren que la mascarita pico grueso puede catalogarse como especie potencial a utilizar hábitats suburbanos cuando éstos son similares a los hábitats en los que se distribuye de manera natural.The first record of the Grey-crowned Yellowthroat (Geothlypis poliocephala in the Transmexican Volcanic Belt biogeographic region (Mexico, within the Morelia city suburbs is presented. Sites were this parulid was sighted / captured were located 427 m higher than its described altitudinal range. This could be due to 2 factors: 1 urbanization generates suitable habitats for this species in periurban areas, and 2 temperature values have increased in the region where the city of Morelia is located. These factors allow that a lowland bird species can inhabit in more elevated areas. Thus, our records suggest that the Grey-crowned Yellowthroat can be catalogued as potential to use suburban environments when these are similar to those used by the species on its natural distribution area.

  2. Altitudinal vegetation belts in the high-Andes of central Chile (33°S Pisos altitudinales de vegetación en los Andes de Chile central (33°S

    Directory of Open Access Journals (Sweden)

    Lohengrin A. Cavieres

    2000-06-01

    Full Text Available The limits of alpine vegetation belts have been established mainly based on physiognomic criteria. However, a more objective approach for fixing limits of vegetation belts are methods based on species composition and relative abundance of each species. While these methods are more time consuming, they are more detailed and permit the detection of physical factors affecting the limits of vegetation belts. In this paper we: 1 describe the altitudinal changes of vegetation above timberline, 2 compare vegetation belts defined with physiognomy and two floristic methods (a qualitative one based on altitudinal changes in species composition, and a quantitative one based on changes in dominant species; and 3 detect some environmental factors responsible for the altitudinal distribution of alpine vegetation between 2100 and 3700 masl in the Andes of Santiago, central Chile (33°S. There was a complete agreement between the different methods in delimiting the subalpine belt. However, in the lower alpine belt (the cushion's belt floristic methods subdivided it in 2-3 sub-belts. In the floristic methods, elevations 3500-3700 that formed the higher alpine belt segregated in separate ways because they have no species in common. Physiognomic descriptions lose relevant information about species distribution, especially at higher elevations. Mean annual temperature and nitrogen content of soil are the main environmental factors affecting the altitudinal limits of vegetation belts in the central Chilean AndesLa delimitación de los pisos altitudinales de vegetación andina se ha basado principalmente en criterios fisionómicos. Sin embargo, un criterio más objetivo para la delimitación es usar métodos basados en la composición y abundancia relativa de las especies presentes. Mientras estos métodos requieren de un mayor esfuerzo de muestreo, son más detallados y permiten detectar factores físicos involucrados en la delimitación altitudinal de la vegetaci

  3. Will Climate Change, Genetic and Demographic Variation or Rat Predation Pose the Greatest Risk for Persistence of an Altitudinally Distributed Island Endemic?

    Directory of Open Access Journals (Sweden)

    Alison Shapcott

    2012-11-01

    Full Text Available Species endemic to mountains on oceanic islands are subject to a number of existing threats (in particular, invasive species along with the impacts of a rapidly changing climate. The Lord Howe Island endemic palm Hedyscepe canterburyana is restricted to two mountains above 300 m altitude. Predation by the introduced Black Rat (Rattus rattus is known to significantly reduce seedling recruitment. We examined the variation in Hedyscepe in terms of genetic variation, morphology, reproductive output and demographic structure, across an altitudinal gradient. We used demographic data to model population persistence under climate change predictions of upward range contraction incorporating long-term climatic records for Lord Howe Island. We also accounted for alternative levels of rat predation into the model to reflect management options for control. We found that Lord Howe Island is getting warmer and drier and quantified the degree of temperature change with altitude (0.9 °C per 100 m. For H. canterburyana, differences in development rates, population structure, reproductive output and population growth rate were identified between altitudes. In contrast, genetic variation was high and did not vary with altitude. There is no evidence of an upward range contraction as was predicted and recruitment was greatest at lower altitudes. Our models predicted slow population decline in the species and that the highest altitude populations are under greatest threat of extinction. Removal of rat predation would significantly enhance future persistence of this species.

  4. Altitudinal and thermal gradients of hepatic Cyp1A gene expression in natural populations of Salmo trutta from high mountain lakes and their correlation with organohalogen loads

    Energy Technology Data Exchange (ETDEWEB)

    Jarque, Sergio; Gallego, Eva [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034-Barcelona, Catalonia (Spain); Bartrons, Mireia; Catalan, Jordi [Center for Advanced Studies of Blanes (CEAB-CSIC), Acces Cala St. Francesc 14, 17300-Blanes, Catalonia (Spain); Grimalt, Joan O. [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034-Barcelona, Catalonia (Spain); Pina, Benjamin, E-mail: bpcbmc@cid.csic.e [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034-Barcelona, Catalonia (Spain)

    2010-05-15

    The biomarker of xenobiotic exposure cytochrome p450A1 (Cyp1A) was used to analyze the biological response to chemical pollution in Salmo trutta (brown trout) from nine high mountain European lakes in Norway, Tatras, Tyrol, and central Pyrenees. Hepatic Cyp1A mRNA levels correlated both with the reciprocal of absolute annual average air temperatures of the sampled lakes and with muscle concentrations of several hydrophobic organohalogen compounds (OC), including chlorinated polychlorobiphenyls (PCB), DDE, and DDT. The correlation between Cyp1A expression and OC content was observed across the whole temperature range (between -0.7 deg. C and +6.2 deg. C), but also in the absence of any thermal gradient. We concluded that airborne pollutants accumulate in high mountain lake fish at concentrations high enough to increase Cyp1A expression, among other possible effects. As geographical distribution of semi-volatile OC is strongly influenced by air temperatures, future climate modifications will potentially enhance their physiological effects in lake ecosystems. - Altitudinal gradients of hepatic Cyp1A gene expression in mountain trout correlate with geographic and individual organohalogen distribution.

  5. Topology of Plant - Flower-Visitor Networks in a Tropical Mountain Forest: Insights on the Role of Altitudinal and Temporal Variation.

    Science.gov (United States)

    Cuartas-Hernández, Sandra; Medel, Rodrigo

    2015-01-01

    Understanding the factors determining the spatial and temporal variation of ecological networks is fundamental to the knowledge of their dynamics and functioning. In this study, we evaluate the effect of elevation and time on the structure of plant-flower-visitor networks in a Colombian mountain forest. We examine the level of generalization of plant and animal species and the identity of interactions in 44 bipartite matrices obtained from eight altitudinal levels, from 2200 to 2900 m during eight consecutive months. The contribution of altitude and time to the overall variation in the number of plant (P) and pollinator (A) species, network size (M), number of interactions (I), connectance (C), and nestedness was evaluated. In general, networks were small, showed high connectance values and non-nested patterns of organization. Variation in P, M, I and C was better accounted by time than elevation, seemingly related to temporal variation in precipitation. Most plant and insect species were specialists and the identity of links showed a high turnover over months and at every 100 m elevation. The partition of the whole system into smaller network units allowed us to detect small-scale patterns of interaction that contrasted with patterns commonly described in cumulative networks. The specialized but erratic pattern of network organization observed in this tropical mountain suggests that high connectance coupled with opportunistic attachment may confer robustness to plant-flower-visitor networks occurring at small spatial and temporal units.

  6. Topology of Plant - Flower-Visitor Networks in a Tropical Mountain Forest: Insights on the Role of Altitudinal and Temporal Variation.

    Directory of Open Access Journals (Sweden)

    Sandra Cuartas-Hernández

    Full Text Available Understanding the factors determining the spatial and temporal variation of ecological networks is fundamental to the knowledge of their dynamics and functioning. In this study, we evaluate the effect of elevation and time on the structure of plant-flower-visitor networks in a Colombian mountain forest. We examine the level of generalization of plant and animal species and the identity of interactions in 44 bipartite matrices obtained from eight altitudinal levels, from 2200 to 2900 m during eight consecutive months. The contribution of altitude and time to the overall variation in the number of plant (P and pollinator (A species, network size (M, number of interactions (I, connectance (C, and nestedness was evaluated. In general, networks were small, showed high connectance values and non-nested patterns of organization. Variation in P, M, I and C was better accounted by time than elevation, seemingly related to temporal variation in precipitation. Most plant and insect species were specialists and the identity of links showed a high turnover over months and at every 100 m elevation. The partition of the whole system into smaller network units allowed us to detect small-scale patterns of interaction that contrasted with patterns commonly described in cumulative networks. The specialized but erratic pattern of network organization observed in this tropical mountain suggests that high connectance coupled with opportunistic attachment may confer robustness to plant-flower-visitor networks occurring at small spatial and temporal units.

  7. Taxonomic study of Onobrychis transcaspica V. Nikitin (Fabaceae in northeastern of Iran with emphasis on altitudinal effect on morphological characters using floristic marker

    Directory of Open Access Journals (Sweden)

    Zeinab Toluei

    2010-07-01

    Full Text Available Onobrychis Miller is the second largest genus of Fabaceae in Iran with nearly 60 species. These species are used as valuable forage plants. Onobrychis sect. Onobrychis with nearly 15 species in Iran is one of the important sections of the genus. Onobrychis transcaspica V. Nikitin, is one of the species of this section that is distributed in NE of Iran. To determine intraspecific variations in O. transcaspica from taxonomic point of view and effective ecological factor, data were collected using special station method. In this way, four special stations were recognized for O. transcaspica in NE of Iran. Results from floristic data (Floristic composition of each special station analysis with MVSP software by PCO method, led to identification of 3 separate groups that was indicative of existence of intraspecific diversity. Morphometric data analysis of individual collected from each special station, by using 65 vegetative and reproductive characters, with PCO and UPGMA methods, confirmed 3 mentioned floristic groups. Ecologic data analysis with CCA Method showed the presence of 3 phenoecodeme based on 3 morphologic groups resulting from altitudinal variations.

  8. Soil carbon and nitrogen stocks in forests along an altitudinal gradient in the eastern Himalayas and a meta-analysis of global data.

    Science.gov (United States)

    Tashi, Sonam; Singh, Balwant; Keitel, Claudia; Adams, Mark

    2016-06-01

    High-altitude soils potentially store a large pool of carbon (C) and nitrogen (N). The assessment of total C and N stocks in soils is vital to understanding the C and N dynamics in terrestrial ecosystems. In this study, we examined effects of altitude and forest composition on soil C and N along a transect from 317 to 3300 m a.s.l. in the eastern Himalayas. We used meta-analysis to establish the context for our results on the effects of altitude on soil C, including variation with depth. Total C and N contents of soils significantly increased with altitude, but decreased with soil depth. Carbon and N were similarly correlated with altitude and temperature, and temperature was seemingly the main driver of soil C along the altitudinal gradient. Altitude accounted for 73% of the variation in C and 47% of the variation in N stocks. Soil pH and cation exchange capacity were correlated with both soil C and N stocks. Increases in soil C and N stocks were related to forest composition, forest basal area as well as quantity of leaf litter that were in turn influenced by altitude and temperature. Concentrations of C in foliage increased by 2.1% for every 1000 m rise in altitude, while that in leaf litter increased by 2.3%. PMID:26840803

  9. 控制地下水位减少节水灌溉稻田氮素淋失%Reducing nitrogen leaching losses from paddy field under water-saving irrigation by water table control

    Institute of Scientific and Technical Information of China (English)

    和玉璞; 张展羽; 徐俊增; 杨士红; 洪大林

    2014-01-01

    Effects of controlled drainage (CD) on nitrogen leaching losses from paddy field under controlled irrigation (CI) were investigated. Water table control levels were managing with the use of a lysimeter equipped with an automatic water table control system. Three drainage treatments were implemented, namely, controlled water table 1, controlled water table 2, and controlled water table 3. For controlled water table 1, the water table control levels were adjusted daily based on the actual water table depths that were measured by using a water table observation well. Water table control levels in controlled water table 2 were controlled based on the rice root zone depths in different stages according to the water table management that was tested in the humid regions of Eastern Canada and Midwestern United States. For controlled water table 3, the water table control levels in different stages were selected based on previous studies in paddy field of Southeast China. The water table control levels in the later tillering stage and milk stage were also adjusted depending on the characteristics of rice growth and cultivation needs. Experiments were conducted in nine drainage type lysimeters with a mobile shelter and gallery. Each lysimeter had an area of 2.5 m × 2 m and a depth of 1.3 m. Influence of rainfall was avoided using the mobile shelter to strictly regulate the soil moisture in CI. Each lysimeter was individually irrigated and drained using a pipe installed with a water meter and a tube (40 mm in inner diameter) installed at 1.2 m below the soil surface, respectively. Subsurface drainage was conducted based on the water table control levels by using an automatic water table control system, which was installed on each drain tube in the gallery. Subsurface drainage water were collected twice at 2d intervals after each fertilizer application followed by 4d intervals. A 7d sampling interval was used during the rest time. NH4+–N and NO3−–N concentrations in the

  10. Reducing nitrogen leaching losses from paddy field under water-saving irrigation by water table control%控制地下水位减少节水灌溉稻田氮素淋失

    Institute of Scientific and Technical Information of China (English)

    和玉璞; 张展羽; 徐俊增; 杨士红; 洪大林

    2014-01-01

    Effects of controlled drainage (CD) on nitrogen leaching losses from paddy field under controlled irrigation (CI) were investigated. Water table control levels were managing with the use of a lysimeter equipped with an automatic water table control system. Three drainage treatments were implemented, namely, controlled water table 1, controlled water table 2, and controlled water table 3. For controlled water table 1, the water table control levels were adjusted daily based on the actual water table depths that were measured by using a water table observation well. Water table control levels in controlled water table 2 were controlled based on the rice root zone depths in different stages according to the water table management that was tested in the humid regions of Eastern Canada and Midwestern United States. For controlled water table 3, the water table control levels in different stages were selected based on previous studies in paddy field of Southeast China. The water table control levels in the later tillering stage and milk stage were also adjusted depending on the characteristics of rice growth and cultivation needs. Experiments were conducted in nine drainage type lysimeters with a mobile shelter and gallery. Each lysimeter had an area of 2.5 m × 2 m and a depth of 1.3 m. Influence of rainfall was avoided using the mobile shelter to strictly regulate the soil moisture in CI. Each lysimeter was individually irrigated and drained using a pipe installed with a water meter and a tube (40 mm in inner diameter) installed at 1.2 m below the soil surface, respectively. Subsurface drainage was conducted based on the water table control levels by using an automatic water table control system, which was installed on each drain tube in the gallery. Subsurface drainage water were collected twice at 2d intervals after each fertilizer application followed by 4d intervals. A 7d sampling interval was used during the rest time. NH4+–N and NO3−–N concentrations in the

  11. Menopause and Bone Loss

    Science.gov (United States)

    Fact Sheet & Menopause Bone Loss How are bone loss and menopause related? Throughout life your body keeps a balance between the loss ... The sooner you take steps to prevent bone loss, the lower your risk of osteoporosis later in life. If you are skipping menstrual periods, have had ...

  12. Influence, Gain and Loss of Neo-Confucianism in the Field of Arts from Modern Times%近代以来新儒学思想在文艺领域的影响与得失

    Institute of Scientific and Technical Information of China (English)

    黄仲山

    2012-01-01

    近代以来的新儒学思想立足儒家传统,试图融通西方文化以改造中国的思想体系,虽然存在许多不足但也造成了一定的影响。新儒学在文艺领域影响了文艺理论的构建和文艺创作的实践,总体来说也是得失参半。在当下儒学越来越受重视的大环境下,新儒学如何存续并继续在文艺领域产生积极的影响,有赖于新儒学本身的理论改造与创新。%Based on the tradition of Confucian from modern times the thoughts of Neo-Confucianism tried to integrate western culture to optimize Chinese ideological system.Though there were lots of shortcomings,it set influences in society to some extent.Neo-Confucianism influenced the construction of literature theories and the creation of arts.Their efforts mixed gains with losses on the whole.Under the great environment of the revival of Confucianism,Neo-Confucianism must innovate in order to preserve the theories and have a positive impact on the field of arts.

  13. Corona helps curb losses

    Energy Technology Data Exchange (ETDEWEB)

    Laasonen, M.; Lahtinen, M.; Lustre, L.

    1996-11-01

    The greatest power losses in electricity transmission arise through a phenomenon called load losses. Corona losses caused by the surface discharge of electricity also constitute a considerable cost item. IVS, the nationwide network company, is investigating corona- induced losses, and has also commissioned similar research from IVO International, the Technical Research Centre of Finland (VTT) and from Tampere University of Technology. The research work strives to gain more in-depth knowledge on the phenomenon of frosting and its impact on corona losses. The correct prediction of frost helps reduce corona losses, while also cutting costs considerably. (orig.)

  14. Hair Loss (Alopecia)

    Science.gov (United States)

    ... Eating disorder: When a person has an eating disorder, hair loss is common. Anorexia (not eating enough) and bulimia (vomiting after eating) can cause hair loss. Medicine Some prescription medicines can cause ...

  15. Hair Loss (Alopecia Areata)

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Hair Loss (Alopecia Areata) Information for adults A A A This ... scalp with a round area of non-scarring hair loss typical of alopecia areata. Overview Alopecia areata is ...

  16. Weight Loss Surgery

    Science.gov (United States)

    Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you ... caused by obesity. There are different types of weight loss surgery. They often limit the amount of food ...

  17. Coping with Memory Loss

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Coping With Memory Loss Share Tweet Linkedin Pin it More sharing ... a health professional. back to top What Causes Memory Loss? Anything that affects cognition—the process of ...

  18. Genes and Hearing Loss

    Science.gov (United States)

    ... Meeting Calendar Find an ENT Doctor Near You Genes and Hearing Loss Genes and Hearing Loss Patient ... mutation may only have dystopia canthorum. How Do Genes Work? Genes are a road map for the ...

  19. Recurrent pregnancy loss

    DEFF Research Database (Denmark)

    Egerup, P; Kolte, A M; Larsen, E C;

    2016-01-01

    STUDY QUESTION: Is there a different prognostic impact for consecutive and non-consecutive early pregnancy losses in women with secondary recurrent pregnancy loss (RPL)? SUMMARY ANSWER: Only consecutive early pregnancy losses after the last birth have a statistically significant negative prognostic...... impact in women with secondary RPL. WHAT IS KNOWN ALREADY: The risk of a new pregnancy loss increases with the number of previous pregnancy losses in patients with RPL. Second trimester losses seem to exhibit a stronger negative impact than early losses. It is unknown whether the sequence of pregnancy...... losses plays a role for the prognosis in patients with a prior birth. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study of pregnancy outcome in patients with unexplained secondary RPL included in three previously published, Danish double-blinded placebo-controlled trials of intravenous...

  20. Genetics of Hearing Loss

    Science.gov (United States)

    ... in Latin America Information For... Media Policy Makers Genetics of Hearing Loss Language: English Español (Spanish) Recommend ... of hearing loss in babies is due to genetic causes. There are also a number of things ...

  1. Pregnancy Loss and Miscarriage

    Science.gov (United States)

    ... Share this: Page Content What is pregnancy loss/miscarriage? A miscarriage, also called pregnancy loss or spontaneous abortion, is ... D.A.M. Medical Encyclopedia. (2010, November 21). Miscarriage . Retrieved May 21, 2012, from http://www.ncbi. ...

  2. 西藏地衣物种多样性的海拔梯度分析%Altitudinal Gradients of Lichen Species Richness in Tibet, China

    Institute of Scientific and Technical Information of China (English)

    黄满荣; 郭威

    2012-01-01

    Altitudinal gradients of lichen species richness in Tibet,China were investigated based on taxonomic and floral literatures.Two hundred and sixty-seven lichen taxa were classified into six groups based on their growth-forms or substrates.The species richness of all groups varied according to altitudinal gradient in a unimodal way.The maximum species richness of most lichen groups were detected between 3400-3900m,corresponding to the upper part of montane boreal coniferous forest,and the extreme height of the occurrence of theses lichen groups in Tibet is higher than that in Nepal.This was probably due to the complex ecosystems in this vegetation zone.The species richness of crustose lichens reached its peak at 5 100-5 400 m,which may be attributed to the disappearance of trees and ample suulight.However,comparisons showed that the species diversity in Tibet was much lower than that in Nepal.This suggests poor understandings of lichen diversity in the area,and further investigations are need.%根据西藏地衣分类和区系的文献资料,对西藏地衣物种多样性的海拔梯度进行了分析.267个分类群按照生长型或者基物被分为六组.每一组地衣的物种丰度随海拔增加呈现单峰曲线形式的变化.多数组物种丰度的峰值出现在海拔3400~3900m之间,对应于山地寒温带针叶林带的上半部分,比尼泊尔对应类群出现极值的海拔要高.此植物带谱内复杂的生态系统可能是物种多样性高的主要原因.壳状地衣物种丰度的峰值出现在5100~5400 m区间则可能是因为该区内高大的树木的消失以及具有充裕的阳光.西藏的地衣物种多样性远低于尼泊尔,两地共有的物种数量很少.对西藏地衣物种多样性的调查不充分应当是其主要原因,因此今后中国地衣学工作者应当加强西藏地衣多样性的研究.

  3. 高原山区车辆轮毂轴承润滑脂流失过程温度场仿真计算%Temperature Field Calculation of Brake Drum for Plateau Mountain Heavy Vehicle Lubricating Grease Loss

    Institute of Scientific and Technical Information of China (English)

    米红英; 管亮; 郭小川; 杨庭栋

    2013-01-01

    According to the technic parameter and working condition of trucks operated under heavy loading and moun-tain driving at altiplano region,the distributing of temperature field and the process of temperature rising of the break drum under frequent breaking were analyzed through computer simulation by COMSOL Multiphysics. The results show that tem-perature between brake drum and block ranges from 430 ℃ to 580 ℃ and the temperature of drum ranges from 150 ℃ to 210 ℃ under continuous braking. Continuous braking is the major reason for lubricating grease loss failure of high tempera-ture.%  根据高原山区重载运输车辆轮毂技术参数及实际使用工况,使用COMSOL Multiphysics软件对连续制动情下制动鼓及轴承温度场分布及温升过程进行模拟仿真分析。结果表明:在高原山区特殊路况下连续制动时,重载车辆动鼓与刹车片摩擦表面的温度在430~580℃之间;轮毂轴承温度随着制动时间增长逐步上升,在150~210℃之间;续制动导致车辆轮毂轴承温度明显升高是造成轮毂轴承润滑脂流失失效的主要原因。

  4. Changing climate and the altitudinal range of avian malaria in the Hawaiian Islands - an ongoing conservation crisis on the island of Kaua'i.

    Science.gov (United States)

    Atkinson, Carter T; Utzurrum, Ruth B; Lapointe, Dennis A; Camp, Richard J; Crampton, Lisa H; Foster, Jeffrey T; Giambelluca, Thomas W

    2014-08-01

    Transmission of avian malaria in the Hawaiian Islands varies across altitudinal gradients and is greatest at elevations below 1500 m where both temperature and moisture are favorable for the sole mosquito vector, Culex quinquefasciatus, and extrinsic sporogonic development of the parasite, Plasmodium relictum. Potential consequences of global warming on this system have been recognized for over a decade with concerns that increases in mean temperatures could lead to expansion of malaria into habitats where cool temperatures currently limit transmission to highly susceptible endemic forest birds. Recent declines in two endangered species on the island of Kaua'i, the 'Akikiki (Oreomystis bairdi) and 'Akeke'e (Loxops caeruleirostris), and retreat of more common native honeycreepers to the last remaining high elevation habitat on the Alaka'i Plateau suggest that predicted changes in disease transmission may be occurring. We compared prevalence of malarial infections in forest birds that were sampled at three locations on the Plateau during 1994-1997 and again during 2007-2013, and also evaluated changes in the occurrence of mosquito larvae in available aquatic habitats during the same time periods. Prevalence of infection increased significantly at the lower (1100 m, 10.3% to 28.2%), middle (1250 m, 8.4% to 12.2%), and upper ends of the Plateau (1350 m, 2.0% to 19.3%). A concurrent increase in detections of Culex larvae in aquatic habitats associated with stream margins indicates that populations of the vector are also increasing. These increases are at least in part due to local transmission because overall prevalence in Kaua'i 'Elepaio (Chasiempis sclateri), a sedentary native species, has increased from 17.2% to 27.0%. Increasing mean air temperatures, declining precipitation, and changes in streamflow that have taken place over the past 20 years are creating environmental conditions throughout major portions of the Alaka'i Plateau that support increased

  5. The altitudinal mobility of wild sheep at the Epigravettian site of Kalavan 1 (Lesser Caucasus, Armenia): Evidence from a sequential isotopic analysis in tooth enamel.

    Science.gov (United States)

    Tornero, Carlos; Balasse, Marie; Bălăşescu, Adrian; Chataigner, Christine; Gasparyan, Boris; Montoya, Cyril

    2016-08-01

    Kalavan 1 is an Epigravettian hunting campsite in the Aregunyats mountain chain in northeastern Armenia (Lesser Caucasus). The site lies at an elevation of 1640 m in a bottleneck that controls the descent into the Barepat Valley from the alpine meadows above. The lithic and faunal assemblages show evidence of the production of hunting weapons, the hunting and targeting of wild sheep (Ovis orientalis), and the constitution of animal product reserves. A seasonal occupation of the site was proposed within a model of occupation by Epigravettian hunter-gatherers that involved a search for obsidian resources in high altitude sources from the spring to the summer and settling at Kalavan 1 at the end of summer or during autumn to coincide with the migration of wild herds from the alpine meadows to the valley. A key parameter of this model is wild sheep ethology, with a specifically seasonal vertical mobility, based on observations from contemporary mouflon populations from the surrounding areas. In this study, the vertical mobility of Paleolithic wild sheep was directly investigated through sequential isotope analysis (δ(18)O, δ(13)C) in teeth. A marked seasonality of birth is suggested that reflects a physiological adaptation to the strong environmental constraints of this mountainous region. Most importantly, a recurrent altitudinal mobility was demonstrated on a seasonal basis, which confirms that wild sheep migrated from lowland areas that they occupied in the winter and then moved to higher altitude meadows during the summer. Last, low inter-individual variability in the stable isotope sequences favors a hypothesis of accumulation for these faunal remains over a short time period. Overall, this new dataset strengthens the previous interpretations for Kalavan 1 and contributes to an understanding of the pattern of occupation of mountain territories by Epigravettian communities. PMID:27457543

  6. Diversity and distribution of Odonata (Insecta) larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico.

    Science.gov (United States)

    Gómez-Anaya, José Antonio; Novelo-Gutiérrez, Rodolfo; Campbell, William Bruce

    2011-12-01

    Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H'), Margalef's Richness Index (R), Simpson's Index as a dominance measure (D) and Pielou's Equitability (J) were used to describe the assemblages, and Renyi's Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC) was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA) was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76%) occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi's diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench's curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation. PMID:22208074

  7. Changing climate and the altitudinal range of avian malaria in the Hawaiian Islands: an ongoing conservation crisis on the island of Kaua'i

    Science.gov (United States)

    Atkinson, Carter T.; Utzurrum, Ruth B.; LaPointe, Dennis A.; Camp, Richard J.; Crampton, Lisa H.; Foster, Jeffrey T.; Giambelluca, Thomas W.

    2014-01-01

    Transmission of avian malaria in the Hawaiian Islands varies across altitudinal gradients and is greatest at elevations below 1500 m where both temperature and moisture are favorable for the sole mosquito vector, Culex quinquefasciatus, and extrinsic sporogonic development of the parasite, Plasmodium relictum. Potential consequences of global warming on this system have been recognized for over a decade with concerns that increases in mean temperatures could lead to expansion of malaria into habitats where cool temperatures currently limit transmission to highly susceptible endemic forest birds. Recent declines in two endangered species on the island of Kaua'i, the ‘Akikiki (Oreomystis bairdi) and ‘Akeke'e (Loxops caeruleirostris), and retreat of more common native honeycreepers to the last remaining high elevation habitat on the Alaka'i Plateau suggest that predicted changes in disease transmission may be occurring. We compared prevalence of malarial infections in forest birds that were sampled at three locations on the Plateau during 1994–1997 and again during 2007–2013, and also evaluated changes in the occurrence of mosquito larvae in available aquatic habitats during the same time periods. Prevalence of infection increased significantly at the lower (1100 m, 10.3% to 28.2%), middle (1250 m, 8.4% to 12.2%), and upper ends of the Plateau (1350 m, 2.0% to 19.3%). A concurrent increase in detections of Culex larvae in aquatic habitats associated with stream margins indicates that populations of the vector are also increasing. These increases are at least in part due to local transmission because overall prevalence in Kaua'i ‘Elepaio (Chasiempis sclateri), a sedentary native species, has increased from 17.2% to 27.0%. Increasing mean air temperatures, declining precipitation, and changes in streamflow that have taken place over the past 20 years are creating environmental conditions throughout major portions of the Alaka'i Plateau that support increased

  8. Hearing loss and music

    Science.gov (United States)

    Noise induced hearing loss - music; Sensory hearing loss - music ... damaged by loud sounds. The human ear is like any other body part -- too much use can damaged it. Over time, repeated exposure to loud noise and music can cause hearing loss.

  9. Drumlin height variability in the New York State drumlin field

    Science.gov (United States)

    Spagnolo, Matteo; Hess, Dale P.; Clark, Chris D.

    2010-05-01

    Although drumlins are among the most common landforms found in formerly glaciated terrain and have been studied for centuries, we still lack a general agreement on their genesis. No one theory of formation can be accepted, though, unless it is capable of explaining the shape of drumlins observed in nature. Most scientists will agree that drumlins have a characteristic shape, but what are the exact figures? While many studies have focused on drumlin length, width and elongation, there is a relatively lack of work on bedform height. In the few exceptions that can be found in the literature, drumlin height has been usually quantified in terms of altitudinal range, with biases related to topography, and from studies of a relatively small number of drumlins. In this work, the height of over 6000 drumlins mapped in New York State, south of Lake Ontario, is analyzed. Specific GIS techniques are applied to effectively quantify drumlin height rather than the once typically measured altitudinal range. Results are discussed statistically and in respect to those reported in the literature as well as those recently emerged from a study of the British Isles. The spatial distribution of drumlin height across the New York State field varies systematically. This paper explores the potential influence of topography, bedrock and glacial history on this variation through spatial analysis. The correlation to other morphometric properties, i.e. length, width and elongation, has also revealed interesting trends.

  10. Diversity and biogeographic affinities of Apionidae (Coleoptera: Curculionoidea along an altitudinal gradient in El Cielo Biosphere Reserve of northeastern Mexico Diversidad y afinidades biogeográficas de Apionidae (Coleoptera: Curculionoidea a lo largo de un gradiente altitudinal en la Reserva de la Biosfera El Cielo en el noreste de México

    Directory of Open Access Journals (Sweden)

    Robert W. Jones

    2012-03-01

    Full Text Available The altitudinal and temporal distributions of species in the family Apionidae (Coleoptera: Curculionoidea were studied in El Cielo Biosphere Reserve (ECBR in the state of Tamaulipas, northeastern Mexico. Species richness, diversity and abundance were recorded along an altitudinal gradient, from 100 to 1 900 m. A total of 571 individuals of 51 species were collected, representing 30% of the total species of Apionidae recorded for Mexico. Richness estimators (Chao 2 indicated that 75% of the species present were sampled. Species richness and diversity was greatest in tropical forests. Species geographic distributions were found to fall into 3 categories: mega-Mexico, tropical and temperate. The majority of the species (55.3% were restricted to mega-Mexico (southern southwestern US to northern Nicaragua, with fewer species with tropical (27.7% and temperate (17.0% distributions. Species with tropical distributions had highest diversity and greater overall abundance in low elevations in tropical forests when compared to higher elevation forests (cloud and pine/oak. In contrast, diversity and abundance for species with temperate and mega-Mexican distributions were similar in all forest types. Greater richness and abundance occurred during the dry season (December through May than the rainy season, suggesting populations of Apionidae were in immature stages during this latter period, with active adults predominating during the dry season, many of which were probably in a non-reproductive physiological state.Se estudiaron las distribuciones altitudinales y temporales de especies de la familia Apionidae (Coleoptera: Curculionoidea en la Reserva de la Biosfera El Cielo, en el norte de México. Riqueza, diversidad y abundancia fueron registrados a través de un gradiente altitudinal de 100 hasta 1 900 m. Se recolectó un total de 571 individuos de Apionidae de 51 especies. La diversidad de especies fue mayor en la selva tropical. La distribución geogr

  11. Magnetic Modulation of Stellar Angular Momentum Loss

    CERN Document Server

    Garraffo, Cecilia; Cohen, Ofer

    2014-01-01

    Angular Momentum Loss is important for understanding astrophysical phenomena such as stellar rotation, magnetic activity, close binaries, and cataclysmic variables. Magnetic breaking is the dominant mechanism in the spin down of young late-type stars. We have studied angular momentum loss as a function of stellar magnetic activity. We argue that the complexity of the field and its latitudinal distribution are crucial for angular momentum loss rates. In this work we discuss how angular momentum is modulated by magnetic cycles, and how stellar spin down is not just a simple function of large scale magnetic field strength.

  12. Losses of runaway electrons during ergodization

    Science.gov (United States)

    Finken, K. H.; Abdullaev, S. S.; Jakubowski, M.; Jaspers, R.; Lehnen, M.; Zimmermann, O.

    2006-04-01

    The dynamic ergodic divertor (DED) of TEXTOR has been applied to runaway discharges. The runaway electrons (ɛ < 30 MeV) are developed as probes for investigating the internal magnetic field line structure in the plasma. Complementary diagnostics are used, namely neutron measurements for the loss of the runaways and synchrotron radiation for the detection inside the plasma. During the DED phase, three features of the runaway electrons are found: a sudden loss from the just formed ergodic layer, an enhanced diffusive transport and very sudden loss events which may be related to field line reconnection processes.

  13. Heat loss from an open cavity

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  14. Self-field loss in Ag / Bi-2223 tape in various temperatures and frequencies; Ag / Bi-2223 tepu no ondo {center_dot} syuhasu wo kaeta koryu sonshitsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Wakasugi, K.; Natsume, K.; Naito, S.; Murase, S.; Shimamoto, S. [Tohoku Univ., Miyagi (Japan). Graduate School of Engineering

    2000-05-29

    AC losses of high temperature superconductor of oxides in bismuth series at commercial frequency and liquid nitrogen temperature have been reported till now. An AC loss was examined this time over wide temperature range (9 K - 77 K) and various frequencies region (3 Hz - 1500 Hz). Fifty-five Ag-sheathed multifilamentary tape wires were examined. Cooling by heat conduction using GM refrigerator was employed. AC loss was calculated from electric voltage induced inside the sample. As the result, deviation from Norris theory was found at frequency region below about 10 Hz and over 500 Hz. In particular, this trend appeared remarkably at low current and low temperature. (NEDO)

  15. Mechanism and kinetics of the loss of poorly soluble drugs from liposomal carriers studied by a novel flow field-flow fractionation-based drug release-/transfer-assay.

    Science.gov (United States)

    Hinna, Askell Hvid; Hupfeld, Stefan; Kuntsche, Judith; Bauer-Brandl, Annette; Brandl, Martin

    2016-06-28

    Liposomes represent a versatile drug formulation approach e.g. for improving the water-solubility of poorly soluble drugs but also to achieve drug targeting and controlled release. For the latter applications it is essential that the drug remains associated with the liposomal carrier during transit in the vascular bed. A range of in vitro test methods has been suggested over the years for prediction of the release of drug from liposomal carriers. The majority of these fail to give a realistic prediction for poorly water-soluble drugs due to the intrinsic tendency of such compounds to remain associated with liposome bilayers even upon extensive dilution. Upon i.v. injection, in contrast, rapid drug loss often occurs due to drug transfer from the liposomal carriers to endogenous lipophilic sinks such as lipoproteins, plasma proteins or membranes of red blood cells and endothelial cells. Here we report on the application of a recently introduced in vitro predictive drug transfer assay based on incubation of the liposomal drug carrier with large multilamellar liposomes, the latter serving as a biomimetic model sink, using flow field-flow fractionation as a tool to separate the two types of liposomes. By quantifying the amount of drug remaining associated with the liposomal drug carrier as well as that transferred to the acceptor liposomes at distinct times of incubation, both the kinetics of drug transfer and release to the water phase could be established for the model drug p-THPP (5,10,15,20-tetrakis(4-hydroxyphenyl)21H,23H-porphine). p-THPP is structurally similar to temoporfin, a photosensitizer which is under clinical evaluation in a liposomal formulation. Mechanistic insights were gained by varying the donor-to-acceptor lipid mass ratio, size and lamellarity of the liposomes. Drug transfer kinetics from one liposome to another was found rate determining as compared to redistribution from the outermost to the inner concentric bilayers, such that the overall

  16. Autoimmunity in visual loss.

    Science.gov (United States)

    Petzold, Axel; Wong, Sui; Plant, Gordon T

    2016-01-01

    Neuroretinitis) are of obscure pathogenesis but an autoimmune disorder of the post-infectious type is plausible. Visual loss in autoimmunity is an expanding field: the most significant advances in research have resulted from taking a well characterised phenotype and making educated guesses at the possible molecular targets of autoimmune attack.

  17. Diversity, distribution pattern and seasonal variation in moth assemblages along altitudinal gradient in Gangotri landscape area, Western Himalaya, Uttarakhand, India

    Directory of Open Access Journals (Sweden)

    A.K. Sanyal

    2013-02-01

    Full Text Available Field survey was conducted at different altitudes and land-use areas in the two protected areas, viz., Gangotri National Park and Govind National Park of Uttarkashi District, Uttarakhand, India. A total of 475 specimens of moth representing 436 morphospecies were collected using light trap method during the survey conducted between September 2008-May 2010. Preliminary findings show a decreasing diversity with increasing altitude. Subalpine areas were least diverse and subtropical areas had the highest diversity of moths. The greatest number of specimens were collected during the summer and post-monsoon period. The lunar phase had a significant effect on catch success with new moon days resulting in the largest catches and full moon days resulting in the least number of species as well as individuals. Of the thirty two species mentioned in Appendix 1, nine species are first time record from the state Uttarakhand. Four species are new record from Western Himalaya within Indian Territory, and also first time recorded from entire Himalayan landscape. As there was no previous comprehensive study on the moth diversity of Gangotri landscape area, all the 32 species described could be regarded as new record from these two protected areas.

  18. Handbook on loss reserving

    CERN Document Server

    Schmidt, Klaus; Schnaus, Anja

    2016-01-01

    This handbook presents the basic aspects of actuarial loss reserving. Besides the traditional methods, it also includes a description of more recent ones and a discussion of certain problems occurring in actuarial practice, like inflation, scarce data, large claims, slow loss development, the use of market statistics, the need for simulation techniques and the task of calculating best estimates and ranges of future losses. In property and casualty insurance the provisions for payment obligations from losses that have occurred but have not yet been settled usually constitute the largest item on the liabilities side of an insurer's balance sheet. For this reason, the determination and evaluation of these loss reserves is of considerable economic importance for every property and casualty insurer. Actuarial students, academics as well as practicing actuaries will benefit from this overview of the most important actuarial methods of loss reserving by developing an understanding of the underlying stochastic models...

  19. Runaway losses in ergodized plasmas

    Science.gov (United States)

    Finken, K. H.; Abdullaev, S. S.; Jakubowski, M. W.; Jaspers, R.; Lehnen, M.; Schlickeiser, R.; Spatschek, K. H.; Wingen, A.; Wolf, R.; TEXTOR Team

    2007-02-01

    New results from the generation of runaways and the loss of runaway electrons in an ergodized magnetic field are presented. For the generation process, a clear difference between a 'normal' and a clean, freshly boronized wall condition has been found. Under clean wall conditions, one observes at low densities not only the runaway electrons with energies up to 30 MeV and at discharges with even lower electron density one finds more runaway electrons but at an energy in the low-MeV regime. The runaway electrons are utilized as test particles for revealing the ergodized magnetic field line structure. For the measurements the m/n = 6/2 base mode configuration of the dynamic ergodic divertor (DED), has been applied. One observes a clear modification of the radial runaway profile with preferential losses in the ergodized zone. From the loss rate of the runaway electrons due to ergodization and from the redistribution of the runaways after the DED phase, the diffusion rate is estimated to be of the order of 0.1 m2 s-1.

  20. Hereditary Hearing Loss.

    Science.gov (United States)

    Tran, LenhAnh P.; Grundfast, Kenneth M.

    1997-01-01

    This article discusses inheritance patterns in hearing loss, epidemiology, clues to genetic causes, locating genes that cause hereditary disorders, genes related to hearing loss disorders in individuals with Usher syndrome, Waardenburg syndrome, Treacher-Collins syndrome, Branchio-oto-renal and Pendred syndromes, and the significance of finding…

  1. Loss muinasjuturaamatust / Agu Veetamm

    Index Scriptorium Estoniae

    Veetamm, Agu, 1953-

    2004-01-01

    Ballindaloch on üks väheseid Shoti losse, kus omanikud aastaringselt elavad. 450 aastat on loss kuulunud Macpherson-Grantide suguvõsale. Praegu on lossi omanikuks Clare Nancy Macpherson-Grant Russell, kelle kujundatud on kiviktaimla ja rosaarium. Lossi ajaloost, omanikest, ümberehitustest, ringkäigust lossis, pargist. 14 ill

  2. Loss Tolerant Optical Qubits

    CERN Document Server

    Ralph, T C; Gilchrist, A; Gilchrist, Alexei

    2005-01-01

    We present a linear optics quantum computation scheme that employs a new encoding approach that incrementally adds qubits and is tolerant to photon loss errors. The scheme employs a circuit model but uses techniques from cluster state computation and achieves comparable resource usage. To illustrate our techniques we describe a quantum memory which is fault tolerant to photon loss.

  3. Help! It's Hair Loss!

    Science.gov (United States)

    ... Homework? Here's Help White House Lunch Recipes Help! It's Hair Loss! KidsHealth > For Kids > Help! It's Hair Loss! Print A A A Text Size ... part above the skin, is dead. (That's why it doesn't hurt to get a haircut!) This ...

  4. Gaseous nitrogen losses from field plots grown with pea (Pisum sativum L.) or spring barley (Hordeum vulgare L.) estimated by 15N mass balance and acetylene inhibition techniques

    DEFF Research Database (Denmark)

    Bertelsen, F.; Jensen, E.S.

    1992-01-01

    by the acetylene-inhibition technique were negligible. A substantial amount of fertilizer N was unaccounted for by the N-15 mass balance, especially in the pea plots. The loss took place during the period of grain-filling in which no leaching occurred, and was accompanied by a decrease in N-15 content...... of the plants. Volatilization of ammonia from the aerial parts of the plants is a possible explanation of the observed loss. An estimation of denitrification relying only on the N-15 mass balance would have resulted in an overestimation of denitrification....

  5. Gain and Loss on Art Field Trips: the Field Trip of Jianshui and Mengzi by 2009 Art Major%艺术采风得与失——以2009级艺术专业建水、蒙自采风为例

    Institute of Scientific and Technical Information of China (English)

    唐应龙; 赵昂

    2012-01-01

    艺术采风是理论与实践相结合的体验性课程,既要通过田野了解民间艺术现状,又要在实践中运用课堂学习的理论知识,其效果较难实现。本文选择了一些学生的采风日记、访谈实录,点评得失,反思跟进,彰显提前案头工作的意义,探索采风日记的写作要点及如何实现艺术采风的目标。%Art of collecting folk songs is an experiencing course combining theory with practice. We should not only realize the current situation of folk arts through the field, but also apply the theory to the practice. This article chooses some students' col- lecting diaries and interviews to comment on the gain and loss, as well as to rethink and improve the good questioning techniques. All of those would demonstrate the significance of bring the desk - bound job forward, explore the writing essentials of collecting diary, and how to achieve the goals of the art of collecting folk songs.

  6. Sudden sensorineural hearing loss.

    Science.gov (United States)

    Stew, B T; Fishpool, S J C; Williams, H

    2012-02-01

    Sudden onset sensorineural hearing loss is a medical emergency that continues to be poorly understood despite being recognized in the literature since 1944 (De Kleyn, 1944). A commonly used criterion to qualify for this diagnosis is a sensorineural hearing loss over three contiguous pure-tone frequencies of 30 dB or more that develops within 72 hours. The vast majority of cases are unilateral and the estimated annual incidence is 20 per 100 000 persons (Nosrati-Zarenoe et al, 2007). A cause for the hearing loss is only identified in up to 10% of cases but 50% of patients will improve spontaneously (Penido et al, 2009).

  7. Analysis of AC loss in superconducting power devices calculated from short sample data

    OpenAIRE

    Rabbers, J.J.; Haken, ten, Bennie; Kate, ten, F.J.W.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile and the transport current, the local AC loss is calculated. Integration over the conductor length yields the AC loss of the device. The total AC loss of the device is split up in different compone...

  8. Investigation and Determination of Corn Combine Harvester Losses to Introduce Appropriate Methods to Reduce Losses

    Directory of Open Access Journals (Sweden)

    M.R Mostofi Sarkari

    Full Text Available Corn harvesting involves some losses. These losses result in decreased benefits. It is almost impossible to lower losses to zero percent but it can be controlled in an acceptable level. As a result of this research, appropriate methods are introduced to decrease losses and reduce waste. In this project, losses in different part of combine were measured and evaluated according to the available standard method (ASAE S396.2 & S343.3. Harvesting losses include preharvest and during harvest losses comprising ear loss and kernal loss in the header, cylinder and cleaning losses. This project was conducted on farmers’ lands in Gazvin province. Some assessments related to yield factors were evaluated in different parts of farm with specified area, e.g. Plant height, ear number, stem diameter, ear diameter, cob diameter, row/ear and seed/row. All losses evaluated in three treatments which they were: seed moisture content (w.b. in three levels of 19%, 23% and 27%, ground speed in three levels of 0.8, 1.2 and 1.6 ms-1 and cylinder speed of 400, 600 and 800 rpm. The split plot experimental design based on the randomised complete block design (RCBD was used to evaluate treatments. Measured losses compared with standard values to introduce the proper methods to decrease losses and proper adjustments. The results show that appropriate seed moisture content, cylinder and ground speed were 23%, 400 rpm and 1.2 ms-1, respectively. They had minimum total loss which WAS 1.55%, 2.65% and 2.34%, respectivily. The results also show that there was an ear loss in preharvest loss (because of bad weather condition that was 0.95-5.42%, also kernal loss on the header and cylinder loss which all related to improper adjustment of combine but total loss was in an acceptable level and standard. It was variable from 1.55% to 4.02%. Other parameters such as using inexperienced driver, improper combine adjustment, and also nonuniformity of field and ear moisture content in

  9. Terminology for pregnancy loss prior to viability

    DEFF Research Database (Denmark)

    Kolte, A M; Bernardi, L A; Christiansen, O B;

    2015-01-01

    Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from...... different centres. In our opinion, terminology and definitions should be based on clinical findings, and when possible, transvaginal ultrasound. With this Early Pregnancy Consensus Statement, it is our goal to provide clear and consistent terminology for pregnancy loss prior to viability....

  10. What's Hearing Loss?

    Science.gov (United States)

    ... cochlea during an operation. It takes over the job of the damaged or destroyed hair cells in the ... and Communicating A kid with hearing loss may attend a special school, special classes within ...

  11. Prizes for weight loss.

    OpenAIRE

    Englberger, L

    1999-01-01

    A programme of weight loss competitions and associated activities in Tonga, intended to combat obesity and the noncommunicable diseases linked to it, has popular support and the potential to effect significant improvements in health.

  12. Understanding Grief and Loss

    Science.gov (United States)

    ... Other common behaviors include restlessness and excessive activity. Religion and spirituality Grief and loss may also cause ... The grieving person’s age and gender The life history of the person who is grieving, including previous ...

  13. Weight loss - unintentional

    Science.gov (United States)

    ... urinating more than usual? Have you lost any hair? What medicines are you taking? Do you feel sad or depressed? Are you pleased or concerned with the weight loss? You may need to see a dietitian for nutrition advice.

  14. Prizes for weight loss.

    Science.gov (United States)

    Englberger, L.

    1999-01-01

    A programme of weight loss competitions and associated activities in Tonga, intended to combat obesity and the noncommunicable diseases linked to it, has popular support and the potential to effect significant improvements in health. PMID:10063662

  15. Bone Loss in IBD

    Science.gov (United States)

    ... DENSITY? Although bone seems as hard as a rock, it’s actually living tissue. Throughout your life, old ... available Bone Loss (.pdf) File: 290 KB 733 Third Avenue, Suite 510, New York, NY 10017 | 800- ...

  16. Types of Hearing Loss

    Science.gov (United States)

    ... on this topic can be found in our Audiology Information Series [PDF]. Hearing loss can be categorized ... speech-language pathologists; speech, language, and hearing scientists; audiology and speech-language pathology support personnel; and students. ...

  17. Effect of loss cone on confinement in toroidal helical device

    International Nuclear Information System (INIS)

    Analytical estimation is given on the loss cone in the toroidal helical devices in the presence of the radial electric field and the modulation of the helical ripple. The minimum energy of particles entering the loss cone is calculated. The modulation is not always effective in reducing the loss in the presence of the radial electric field. The plasma loss due to the loss cone is estimated in the collisionless limit. The radial electric field is estimated in the presence of the loss cone. It is found that the transition to the solution with positive radial electric field, which is necessary to achieve the high-ion-temperature mode, becomes difficult. This difficulty is large for the systems with the small helical ripple. (author)

  18. Female Pattern Hair Loss

    OpenAIRE

    Herskovitz, Ingrid; Tosti, Antonella

    2013-01-01

    Context: Female pattern hair loss (FPHL) also known as female androgenetic alopecia is a common condition afflicting millions of women that can be cosmetically disrupting. Prompt diagnosis and treatment are essential for obtaining optimal outcome. This review addresses the clinical presentation of female pattern hair loss, its differential diagnosis and treatment modalities. Evidence Acquisition: A) Diffuse thinning of the crown region with preservation of the frontal hairline (Ludwig’s type)...

  19. Genetic Effects on Sensorineural Hearing Loss and Evidence-based Treatment for Sensorineural Hearing Loss

    Institute of Scientific and Technical Information of China (English)

    Yong-qiang Yu; Huai-an Yang; Ming Xiao; Jing-wei Wang; Dong-yan Huang; Yagesh Bhambhani; Lyn Sonnenberg

    2015-01-01

    In this article, the mechanism of inheritance behind inherited hearing loss and genetic susceptibility in noise-induced hearing loss are reviewed. Conventional treatments for sensorineural hearing loss (SNHL), i.e. hearing aid and cochlear implant, are effective for some cases, but not without limitations. For example, they provide little benefit for patients of profound SNHL or neural hearing loss, especially when the hearing loss is in poor dynamic range and with low frequency resolution. We emphasize the most recent evidence-based treatment in this field, which includes gene therapy and allotransplantation of stem cells. Their promising results have shown that they might be options of treatment for profound SNHL and neural hearing loss. Although some treatments are still at the experimental stage, it is helpful to be aware of the novel therapies and endeavour to explore the feasibility of their clinical application.

  20. Loss Allocation in Securitization Transactions

    OpenAIRE

    Günter Franke; Markus Herrmann; Thomas Weber

    2011-01-01

    This paper analyses the loss allocation to First, Second and Third Loss Positions in European collateralized debt obligation transactions. The quality of the underlying asset pool plays a predominant role for the loss allocation. A lower asset pool quality induces the originator to take a higher First Loss Position, but, in a synthetic transaction, a smaller Third Loss Position. The share of expected default losses, borne by the First Loss Position, is largely independent of asset pool qualit...

  1. Comparison between methods of evaluation of soybean mechanized harvesting losses

    Directory of Open Access Journals (Sweden)

    Ariel Muncio Compagnon

    2012-09-01

    Full Text Available he soybean is of great importance in the Brazilian agricultural scenario and both productivity and the area cultivated to each crop are increasing, demanding more speed and quality at harvest. However, losses are recorded in the mechanical harvesting of soybeans, a fundamental stage in the production process of field crops. Looking to quantify these losses was used in this study display a loss, and results were compared with the losses collected manually. Data were collected at Fazenda São Luiz, in the city of Santa Juliana - MG, with a harvester dual-rotor axial, with a platform of 9.14 m. We assessed 40 points in the day and night periods, and the variables: water content of grains, travel speed, plant height, height of first pod, grain yield, losses due to disability at the time of cutting, trail system, cleaning system and total grain losses and losses in the separation of clean grain. The soybean harvest at night had higher levels of coincidence between the obtained sensor separation and the losses measured in the field, while during the day there was a better match for the sensor track. Losses of grain deficiency in cutting height contribute largely to the loss of soybeans at harvest during the day, reducing the correlation between the losses estimated in the field and the losses obtained from the sensors.

  2. ESTRUCTURA DE UNA COMUNIDAD DE LÍQUENES Y MORFOLOGIA DEL GÉNERO Sticta(STICTACEAE EN UN GRADIENTE ALTITUDINAL Lichen Community Structure And Morphological Changes In The Genus Sticta (STICTACEAE Associated To An Altitude Gradient

    Directory of Open Access Journals (Sweden)

    ÁLVARO LUÍS PÉREZ QUINTERO

    Full Text Available La distribución y el crecimiento de los líquenes están condicionados por diferentes factores ambientales, entre estos la variación en gradientes altitudinales. En la cordillera Oriental de los Andes de Colombia, no se han realizado estudios sobre zonación altitudinal de líquenes. En este trabajo se estudiaron las variaciones en la estructura de la comunidad de líquenes epifitos en un gradiente altitudinal (2.000- 2.600 m en el PNN Tatamá. Se encontró que con el aumento en altura hay una disminución en riqueza y diversidad, siendo esto una desviación del patrón encontrado generalmente en otros trabajos sobre líquenes y gradientes altitudinales. La comunidad a bajas alturas se compone principalmente de líquenes fruticosos (cobertura de 30% a 2.070 m y 0% a 2.560 m y a mayores alturas de líquenes foliosos (cobertura de 15% a 2.070 m y 43% a 2.560 m. La altura, además de influenciar la estructura de la comunidad de los líquenes, puede afectar el desarrollo y la morfología de estos. En el género folioso Sticta se presentaron variaciones intraespecificas en la densidad de cifelas (órganos de intercambio gaseoso asociadas a la altura, encontrándose un efecto significativo de la altura sobre la densidad de cifelas en las especies S. andensis y S. gyalocarpa (ANOVA, valor p= 0.008 y 0.05 respectivamente. Esto muestra un mecanismo de adaptación a los cambios ambientales que se dan con la altura.Lichen’s growth and distribution are conditioned by various environemental factors, altitude being an important one. In the Cordillera Oriental of Colombian Andes, there haven’t been studies on lichen’s altitudinal zonation. We studied the variation on lichen community structure along an altitudinal gradient (2000- 2600 m in PNN Tatamá, we found diversity diminishes as altitude increases, this being a variation from what’s generally found in lichen community behavior. At low altitudes, the community was conformed by fruticose lichens

  3. Influence of gear loss factor on the power loss prediction

    OpenAIRE

    C. M. C. G. Fernandes; P. M. T. Marques; R. C. Martins; J. H. O. Seabra

    2015-01-01

    In order to accurately predict the power loss generated by a meshing gear pair the gear loss factor must be properly evaluated. Several gear loss factor formulations were compared, including the author's approach. A gear loss factor calculated considering the load distribution along the path of contact was implemented. The importance of the gear loss factor in the power loss predictions was put in evidence comparing the predictions with experimental results. It was ...

  4. A.C. losses in current-carrying superconductors

    International Nuclear Information System (INIS)

    The feasibility of superconductors for alternating current use depends on successful reduction of losses. Moreover, the demand for large field amplitudes is a stimulation for investigating the nature of a.c. losses (e.g. in the set of poloidal coils in a TOKAMAK). In this thesis, measurements are performed at a.c. superconductivity. Attention is given to various external field conditions as well as to self-field instability. Measurements are performed on different types of wires. A type of wire is searched for with both low losses and a good stabilization under self-field conditions. (G.J.P.)

  5. Weight Loss Nutritional Supplements

    Science.gov (United States)

    Eckerson, Joan M.

    Obesity has reached what may be considered epidemic proportions in the United States, not only for adults but for children. Because of the medical implications and health care costs associated with obesity, as well as the negative social and psychological impacts, many individuals turn to nonprescription nutritional weight loss supplements hoping for a quick fix, and the weight loss industry has responded by offering a variety of products that generates billions of dollars each year in sales. Most nutritional weight loss supplements are purported to work by increasing energy expenditure, modulating carbohydrate or fat metabolism, increasing satiety, inducing diuresis, or blocking fat absorption. To review the literally hundreds of nutritional weight loss supplements available on the market today is well beyond the scope of this chapter. Therefore, several of the most commonly used supplements were selected for critical review, and practical recommendations are provided based on the findings of well controlled, randomized clinical trials that examined their efficacy. In most cases, the nutritional supplements reviewed either elicited no meaningful effect or resulted in changes in body weight and composition that are similar to what occurs through a restricted diet and exercise program. Although there is some evidence to suggest that herbal forms of ephedrine, such as ma huang, combined with caffeine or caffeine and aspirin (i.e., ECA stack) is effective for inducing moderate weight loss in overweight adults, because of the recent ban on ephedra manufacturers must now use ephedra-free ingredients, such as bitter orange, which do not appear to be as effective. The dietary fiber, glucomannan, also appears to hold some promise as a possible treatment for weight loss, but other related forms of dietary fiber, including guar gum and psyllium, are ineffective.

  6. Recurrent Pregnancy Loss

    Directory of Open Access Journals (Sweden)

    Véronique Piroux

    1997-01-01

    Full Text Available Antiphospholipid antibodies (APA are associated with thrombosis, thrombocytopenia and fetal loss but they occur in a variety of diseases. Despite many efforts, a correlation between the specificity of particular subgroups of APA and particular clinical situations remains to be established. The antigens at the origin of APA remain to be identified. We discuss here the possible links between cell apoptosis or necrosis, leading to plasma membrane alterations, and the occurrence of APA in response to sustained stimulation. The pathogenic potential of APA is also considered with respect to recurrent pregnancy loss.

  7. Chronic unilateral vestibular loss.

    Science.gov (United States)

    Kerber, K A

    2016-01-01

    Chronic unilateral vestibular loss is a condition defined by the presence of reduced function of the peripheral vestibular system on one side, which has generally persisted for 3 or more months. The deficit is demonstrated by a reduction of the vestibular-ocular reflex either at the bedside or on laboratory testing. Though some patients with chronic vestibular loss have disabling symptoms, others are asymptomatic. Causes include a viral/postviral disorder, Menière's disease, structural lesions, ischemia, and trauma. Any other systemic or genetic disorder would be expected to involve both sides at some point. PMID:27638074

  8. Telogen Effluvium Hair Loss

    Science.gov (United States)

    ... for Authors Information for Reviewers Human & Animal Rights Job Postings Sections of the JAOCD JAOCD Archive Published Members Online Dermatology Journals Edit This Favorite Name: Category: Share: Yes No, Keep Private Telogen Effluvium Hair Loss Share | It is normal to lose up to ...

  9. OI Issues: Hearing Loss

    Science.gov (United States)

    ... that focuses on hearing loss and hearing issues. Miracle Ear Children’s Foundation P.O. Box 59261 Minneapolis, MN 55459-0261 (800) 234-5422 www.miracle-ear.com Miracle Ear Children’s Foundation provides free ...

  10. Autism and Hearing Loss.

    Science.gov (United States)

    Rosenhall, Ulf; Nordin, Viviann; Sandstrom, Mikael; Ahlsen, Gunilla; Gillberg, Christopher

    1999-01-01

    Children and adolescents (N=199) with autistic disorder were audiologically evaluated. Mild to moderate hearing loss was diagnosed in 7.9 percent, with deafness diagnosed in 3.5 percent of all cases, which represented a prevalence considerably above that in the general population and comparable to the prevalence found in populations with mental…

  11. Loss and damage

    Science.gov (United States)

    Huq, Saleemul; Roberts, Erin; Fenton, Adrian

    2013-11-01

    Loss and damage is a relative newcomer to the climate change agenda. It has the potential to reinvigorate existing mitigation and adaptation efforts, but this will ultimately require leadership from developed countries and enhanced understanding of several key issues, such as limits to adaptation.

  12. Responding to Amphibian Loss

    NARCIS (Netherlands)

    J.R. Mendelson III; K.R. Lips; R.W. Gagliardo; G.B. Rabb; J.P. Collins; J.E. Diffendorfer; P. Daszak; R. Ibáñez D.; K.C. Zippel; D.P. Lawson; K.M. Wright; S.N. Stuart; C. Gascon; H.R. da Silva; P.A. Burrowes; R.L. Joglar; E. La Marca; S. Lötters; L.H. du Preez; C. Weldon; A. Hyatt; J.V. Rodriguez-Mahecha; S. Hunt; H. Robertson; B. Lock; C.J. Raxworthy; D.R. Frost; R.C. Lacy; R.A. Alford; J.A. Campbell; G. Parra-Olea; F. Bolaños; J.J. Calvo Domingo; T. Halliday; J.B. Murphy; M.H. Wake; L.A. Coloma; S.L. Kuzmin; M.S. Price; K.M. Howell; M. Lau; R. Pethiyagoda; M. Boone; M.J. Lannoo; A.R. Blaustein; A. Dobson; R.A. Griffiths; M.L. Crump; D.B. Wake; E.D. Brodie Jr

    2006-01-01

    In their Policy Forum "Confronting amphibian declines and extinctions" (7 July, p. 48), J. R. Mendelson III and colleagues offer a strategy for "stopping" the widespread losses of frogs, toads, and salamanders. Disease research and captive breeding figure prominently in their call for action.

  13. Heat loss from Buildings

    DEFF Research Database (Denmark)

    Karlsson, Kenneth; Næraa, Rikke

    1997-01-01

    Determination of heat loss coefficients for buildings in Denmark. The coefficient are determined for 15 building groups and 3 year intervals. They are based on the BBR-registre and assumptions of U-values(W/K*m2)and computed in a simple spreed sheet model.The results are used in the REVEILLE...... project for calculations in the SESAM model....

  14. Cascadia's Staggering Losses

    Science.gov (United States)

    Wang, Y.; Vogt, B.

    2001-05-01

    Recent worldwide earthquakes have resulted in staggering losses. The Northridge, California; Kobe, Japan; Loma Prieta, California; Izmit, Turkey; Chi-Chi, Taiwan; and Bhuj, India earthquakes, which range from magnitudes 6.7 to 7.7, have all occurred near populated areas. These earthquakes have resulted in estimated losses between \\3 and \\300 billion, with tens to tens of thousands of fatalities. Subduction zones are capable of producing the largest earthquakes. The 1939 M7.8 Chilean, the 1960 M9.5 Chilean, the 1964 M9.2 Alaskan, the 1970 M7.8 Peruvian, the 1985 M7.9 Mexico City and the 2001 M7.7 Bhuj earthquakes are damaging subduction zone quakes. The Cascadia fault zone poses a tremendous hazard in the Pacific Northwest due to the ground shaking and tsunami inundation hazards combined with the population. To address the Cascadia subduction zone threat, the Oregon Department of Geology and Mineral Industries conducted a preliminary statewide loss study. The 1998 Oregon study incorporated a M8.5 quake, the influence of near surface soil effects and default building, social and economic data available in FEMA's HAZUS97 software. Direct financial losses are projected at over \\$12 billion. Casualties are estimated at about 13,000. Over 5,000 of the casualties are estimated to result in fatalities from hazards relating to tsunamis and unreinforced masonry buildings.

  15. From Loss to Awakening

    Institute of Scientific and Technical Information of China (English)

    高崇毅; 李柳英

    2007-01-01

    Katherine Mansfield's short story A Dill Pickle (1917) shows a full picture of the female image to the readers: Vera's loss in love and her awakening from the sorrow and despair.Vera changes during the talk with her former boyfriend and achieves in awakening as a female at last.

  16. Wind farm array wake losses

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W. [Impact Weather, Washougal, WA (United States); McCarthy, E.F. [Wind Economics & Technology, Inc., Martinez, CA (United States)

    1997-12-31

    A wind turbine wake study was conducted in the summer of 1987 at an Altamont Pass wind electric generating facility. The wind speed deficits, turbulence, and power deficits from an array consisting of several rows of wind turbines is discussed. A total of nine different test configurations were evaluated for a downwind spacing ranging from 7 rotor diameters (RD) to 34 RD and a cross wind spacing of 1.3 RD and 2.7 RD. Wake power deficits of 15% were measured at 16 RD and power losses of a few percent were even measurable at 27 RD for the closer cross wind spacing. For several rows of turbines separated by 7-9 RD the wake zones overlapped and formed compound wakes with higher velocity deficits. The wind speed and direction turbulence in the wake was much higher than the ambient turbulence. The results from this study are compared to the findings from other similar field measurements.

  17. Loss of Heterozygosity

    OpenAIRE

    sprotocols

    2014-01-01

    Author: Molecular Profiling Initiative, NCI *This method was successful in our lab using prostate tissue and for our specific objectives. Investigators must be aware that they will need to tailor the following protocol for their own research objectives and tissue under study*. This method is used to detect genomic DNA deletions in tumor cells. For a more detailed discussion of applying this approach to microdissected samples, see [Allelic Loss Studies](http://cgap-mf.nih.gov/ProstateE...

  18. Valuing Catastrophic Citrus Losses

    OpenAIRE

    Adams, Damian C.; Kilmer, Richard L.; Moss, Charles B.; Schmitz, Andrew

    2004-01-01

    Courts are often required to estimate changes in welfare to agricultural operations from catastrophic events. For example, courts must assign damages in lawsuits, such as with pesticide drift cases, or determine "just compensation" when the government takes private land for public use, as with the removal of dairy farms from environmentally sensitive land or destruction of canker-contaminated citrus trees. In economics, the traditional method of quantifying producer losses is estimating chang...

  19. Decisions under unpredictable losses

    Directory of Open Access Journals (Sweden)

    Ali Ahmed

    2007-10-01

    Full Text Available An experimental test of the descriptive adequacy of the extit{restated diversification principle} is presented. The principle postulates that risk-averse utility maximizers will pool risks for their mutual benefit, even if information is missing about the probabilities of losses. It is enough for people to assume that they face equal risks when they pool risks. The results of the experiment support the principle.

  20. ADT fast losses MD

    CERN Document Server

    Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

    2013-01-01

    The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

  1. [Loss and mourning].

    Science.gov (United States)

    Cabodevilla, I

    2007-01-01

    The human being needs ties to grow and develop. When some of these ties are broken a period of great intensity arises that we call mourning. If the loss is radical and definitive, as in the case of death, all of the person's dimensions are affected (the physical, emotional, cognitive, behavioural, social and spiritual dimensions), to such an extent that the person can feel unable to overcome this and/or develop a pathological mourning that requires professional intervention for recovery. Many factors intervene in the type of mourning, such as circumstances of the death, relation to the deceased, personality, previous experience and the socio-family context. For there to be complete recovery following a loss, the person affected passes through a series of stages or phases and must carry out four basic tasks: 1. Accept the reality of the loss. 2. Express emotions and pain. 3. Adapt to a setting from which the loved one is absent. 4. Emotionally resituate the deceased and continue living. PMID:18227888

  2. Mechanism and kinetics of the loss of poorly soluble drugs from liposomal carriers studied by a novel flow field-flow fractionation-based drug release-/transfer-assay

    DEFF Research Database (Denmark)

    Hinna, Askell Hvid; Hupfeld, Stefan; Kuntsche, Judith;

    2016-01-01

    associated with liposome bilayers even upon extensive dilution. Upon i.v. injection, in contrast, rapid drug loss often occurs due to drug transfer from the liposomal carriers to endogenous lipophilic sinks such as lipoproteins, plasma proteins or membranes of red blood cells and endothelial cells. Here we...... kinetics from one liposome to another was found rate determining as compared to redistribution from the outermost to the inner concentric bilayers, such that the overall process could be adequately described by a single 1st order kinetic model.By varying the donor-to-acceptor lipid mass ratio in the range.......45) and Sudan III (clogP 6.83). For the more lipophilic compounds, the rate of transfer from the donor liposomes followed the rank order Sudan IV (fastest)>Oil Red O>Sudan Black>p-THPP (slowest). For an equimolar donor-to-acceptor lipid mass ratio, half-lifes of transfer in the range of 12min (Sudan IV...

  3. Hair loss in women.

    Science.gov (United States)

    Camacho-Martínez, Francisco M

    2009-03-01

    Female pattern hair loss (FPHL) is a clinical problem that is becoming more common in women. Female alopecia with androgen increase is called female androgenetic alopecia (FAGA) and without androgen increase is called female pattern hair loss. The clinical picture of typical FAGA begins with a specific "diffuse loss of hair from the parietal or frontovertical areas with an intact frontal hairline." Ludwig called this process "rarefaction." In Ludwig's classification of hair loss in women, progressive type of FAGA, 3 patterns were described: grade I or minimal, grade II or moderate, and grade III or severe. Ludwig also described female androgenetic alopecia with male pattern (FAGA.M) that should be subclassified according to Ebling's or Hamilton-Norwood's classification. FAGA.M may be present in 4 conditions: persistent adrenarche syndrome, alopecia caused by an adrenal or an ovarian tumor, posthysterectomy, and as an involutive alopecia. A more recent classification (Olsen's classification of FPHL) proposes 2 types: early- and late-onset with or without excess of androgens in each. The diagnosis of FPHL is made by clinical history, clinical examination, wash test, dermoscopy, trichoscan, trichograms and laboratory test, especially androgenic determinations. Topical treatment of FPHL is with minoxidil, 2-5% twice daily. When FPHL is associated with high levels of androgens, systemic antiandrogenic therapy is needed. Persistent adrenarche syndrome (adrenal SAHA) and alopecia of adrenal hyperandrogenism is treated with adrenal suppression and antiandrogens. Adrenal suppression is achieved with glucocorticosteroids. Antiandrogens therapy includes cyproterone acetate, drospirenone, spironolactone, flutamide, and finasteride. Excess release of ovarian androgens (ovarian SAHA) and alopecia of ovarian hyperandrogenism is treated with ovarian suppression and antiandrogens. Ovarian suppression includes the use of contraceptives containing an estrogen, ethinylestradiol, and a

  4. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    Archana Singal

    2013-01-01

    Full Text Available Female pattern hair loss (FPHL is a common cause of hair loss in women characterized by diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline. Its prevalence increases with advancing age and is associated with significant psychological morbidity. The pathophysiology of FPHL is still not completely understood and seems to be multifactorial. Although androgens have been implicated, the involvement of androgen-independent mechanisms is evident from frequent lack of clinical or biochemical markers of hyperandrogenism in affected women. The role of genetic polymorphisms involving the androgen and estrogen receptors is being increasingly recognized in its causation and predicting treatment response to anti-androgens. There are different clinical patterns and classifications of FPHL, knowledge of which facilitates patient management and research. Chronic telogen effluvium remains as the most important differential diagnosis. Thorough history, clinical examination, and evaluation are essential to confirm diagnosis. Patients with clinical signs of androgen excess require assessment of biochemical parameters and imaging studies. It is prudent to screen the patients for metabolic syndrome and cardiovascular risk factors. The treatment comprises medical and/or surgical modalities. Medical treatment should be initiated early as it effectively arrests hair loss progression rather than stimulating regrowth. Minoxidil continues to be the first line therapy whereas anti-androgens form the second line of treatment. The progressive nature of FPHL mandates long-term treatment for sustained effect. Medical therapy may be supplemented with cosmetic concealment in those desirous of greater hair density. Surgery may be worthwhile in some carefully selected patients.

  5. The 1981-1982 NCLAN (National Crop Loss Assessment Network) program at LLNL: The effects of ozone and sulfur dioxide, singly and in combination, on field-grown tomato

    Energy Technology Data Exchange (ETDEWEB)

    Surano, K.A.; Mutters, R.G.; Temple, P.J.; Bingham, G.E.; Kercher, J.R.; Shinn, J.H.

    1987-07-01

    The combined effects of ozone (O/sub 3/) and sulfur dioxide (SO/sub 2/) exposures on tomato (Lycopersicon esculentum Mill.) crop yields were measured during the 1981 and 1982 growing seasons. The effort, part of the National Crop Loss Assessment Network (NCLAN), had the objective of determining the yield dose response of tomato grown under commercial conditions. Dose response was determined using step-wise multiple regression techniques and was expressed as reduction in marketable yield as a function of increased pollutant levels. The crops were harvested during mid-September 1981 and during mid-October 1982. No O/sub 3/- or So/sub 2/-induced visible injury symptons (lesions, chlorosis, or becrosis) were apparent on foliage or fruits. Total marketable fruit fresh weight was used as the dependent variable in the regression analysis because it most closely represented the economic value of the crop. Comparison of chambered- and companion-plot data showed that the chambers themselves caused significant effects on the crop. Yields were reduced 12% in 1981 and 24% in 1982 due to the chambers. There was also more unripened fruit within the chambers because of chamber-induced uneven distribution of an aerially-applied ripening agent. Dose-response results were independent of the chamber effects. Based on companion-plot data, the yield of the crop in the research area was 65/plus minus/2 Mg ha/sup /minus/1/ in both years. The research-area yields correlated well with those from the adjacent commercial plantation. With respect to tomato production in the San Joaquin Valley, we recommend that an air quality management strategy be adopted to contain ambient O/sub 3/ concentrations at or below present levels. Containment at present levels would avoid O/sub 3/-induced tomato yield reductions greater than 7%, even during atypical years such as 1982. 26 refs., 17 figs., 9 tabs.

  6. Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

    Science.gov (United States)

    Hamilton, H. B.; Strangas, E.

    1980-01-01

    The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

  7. Tragic loss at CERN

    CERN Multimedia

    CERN Ski Club

    2015-01-01

    Tragic loss at CERN The CERN community is mourning the tragic loss of two members of the CERN Ski Club. On Sunday, April 12, an avalanche buried four out of five skiers, taking part in a ski touring in the region of the Becs de Bosson in Valais (CH). The fifth skier, who had not been buried in the snow,  courageously managed to save two of the skiers, but Hervé Milcent, 49 years, federal ski instructor, and Mattieu Cattin, 33 years, were buried under two to three meters of snow, far down the avalanche slope, and did not survive, despite the fast arrival of the mountain rescue. In its 40 years of existence, the CERN Ski Club, one of the biggest in the Geneva area, has never been confronted with such a tragedy. The passing of Hervé and Matthieu has deeply shocked and saddened all volunteers of the Club as well as the entire alpine community. The ski touring section of the club would like to honour its friend Hervé, who joined the club in 1998. In 2003 he became res...

  8. Pricing Excess-of-loss Reinsurance Contracts Against Catastrophic Loss

    OpenAIRE

    J. David Cummins; Lewis, Christopher M.; Phillips, Richard D.

    1998-01-01

    This paper develops a pricing methodology and pricing estimates for the proposed Federal excess-of- loss (XOL) catastrophe reinsurance contracts. The contracts, proposed by the Clinton Administration, would provide per-occurrence excess-of-loss reinsurance coverage to private insurers and reinsurers, where both the coverage layer and the fixed payout of the contract are based on insurance industry losses, not company losses. In financial terms, the Federal government would be selling earthqua...

  9. Measurements of Beam Ion Loss from the Compact Helical System

    Energy Technology Data Exchange (ETDEWEB)

    D. S. Darrow, M. Isobe, Takashi Kondo, M. Sasao, and the CHS Group National Institute for Fusion Science, Toki, Gifu, Japan

    2010-02-03

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  10. Measurement of AC losses in different former materials

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa;

    1998-01-01

    A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...

  11. Losses in superconducting Niobium Films caused by Interface Tunnel Exchange

    OpenAIRE

    Junginger, Tobias; Weingarten, Wolfgang; Welsch, Carsten

    2012-01-01

    Identifying the loss mechanisms of niobium film cavities enables an accurate determination of applications for future accelerator projects and points to research topics required to mitigate their limitations. Measurements on samples show that the electric field is a dominant loss mechanism for niobium films, acting through interface tunneling between localized states in surface oxides and delocalized states in the superconducting niobium.

  12. Apollo 15 mission. Temporary loss of command module television picture

    Science.gov (United States)

    1973-01-01

    An investigation was made into the temporary loss of command module color television picture by the ground station converter at Mission Control Center. Results show the picture loss was caused by a false synchronization pulse that resulted from the inability of the black level clipping circuit to respond adequately to the video signal when bright sunlight suddenly entered the camera's field of view.

  13. A multiscale soil loss evaluation index

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Exploring the relationships between land use and soil erosion at different scales is a frontier research field and a hot spot topic in contemporary physical geography. Based on the scale-pattern-process theory in landscape ecology and with consideration of such influential factors as land use, topography, soil and rainfall, this paper applies the scale transition method to establishing a soil loss evaluation index at different scales and puts forward a research path and methodology for multiscale soil loss evaluation indices. The multiscale soil loss evaluation index is applied to the evaluation of relationships between land use and soil erosion and the research of soil erosion evaluation at multiple scales. It provides a new method for optimizing the design of regional land use patterns and integrated multiscale research.

  14. Transmission loss between single-mode Gaussian antennas.

    Science.gov (United States)

    Perlot, Nicolas; Rohde, Michael

    2016-08-22

    We analytically derive a set of formulas for the transmission loss in vacuum between antennas that send and receive single-mode Gaussian beams. We relate our results to standard far-field link budget parameters.

  15. Reducing the losses of optical metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Anan [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    The field of metamaterials is driven by fascinating and far-reaching theoretical visions, such as perfect lenses, invisibility cloaking, and enhanced optical nonlinearities. However, losses have become the major obstacle towards real world applications in the optical regime. Reducing the losses of optical metamaterials becomes necessary and extremely important. In this thesis, two approaches are taken to reduce the losses. One is to construct an indefinite medium. Indefinite media are materials where not all the principal components of the permittivity and permeability tensors have the same sign. They do not need the resonances to achieve negative permittivity, ε. So, the losses can be comparatively small. To obtain indefinite media, three-dimensional (3D) optical metallic nanowire media with different structures are designed. They are numerically demonstrated that they are homogeneous effective indefinite anisotropic media by showing that their dispersion relations are hyperbolic. Negative group refraction and pseudo focusing are observed. Another approach is to incorporate gain into metamaterial nanostructures. The nonlinearity of gain is included by a generic four-level atomic model. A computational scheme is presented, which allows for a self-consistent treatment of a dispersive metallic photonic metamaterial coupled to a gain material incorporated into the nanostructure using the finite-difference time-domain (FDTD) method. The loss compensations with gain are done for various structures, from 2D simplified models to 3D realistic structures. Results show the losses of optical metamaterials can be effectively compensated by gain. The effective gain coefficient of the combined system can be much larger than the bulk gain counterpart, due to the strong local-field enhancement.

  16. 油菜苗期性状与其稻茬免耕直播产量损失的关系%Relationship between Seedling Traits and Yield Loss of Rapeseed Direct-Seeded in No-Tillage Rice Stubble Field

    Institute of Scientific and Technical Information of China (English)

    王翠翠; 陈爱武; 雷海霞; 韩自行; 刘芳; 周广生; 吴江生; 傅廷栋

    2011-01-01

    Technique of direct-seeding rape in no-tillage rice stubble field can decrease the labor and reduce the area of winter fallow fields, but its output is often less than the tillage cultivation model.In order to investigate the production constraints of direct-seeding rape in no-tillage field, we designed a pot experiment to determine physiological indices of all lines such as root-shoot ratio, drought resistance, waterlogging tolerance and agronomy nitrogen use efficiency at seedling stage, and designed a field trial to determine the yield loss ratio of 15 lines in the no-tillage mode, then compared the relationship between physiological indices at seedling stage and yield loss ratio in no-tillage mode.The result showed that: (1) differences in characters at maturity period, yield and its components for the same rapeseed line in different cultivation modes depended on different lines; (2) compared with that in the tillage mode, the lines that had small drop in shoot dry weight, economic coefficient or 1000-seed weight in no-tillage cultivation also had small yield loss ratio; (3) yield loss ratio at direct-seeding rape in no-tillage rice stubble field negatively correlated with root-shoot ratio, drought resistance and waterlogging tolerance at seedling stage, but positively correlated with nitrogen use efficiency at seedling stage; (4) the lines that had big root-shoot ratio, good drought resistance and waterlogging tolerance and robust seedling growth should be selected in the course of the cultivation and management, prevention against drought and waterlogging and balanced fertilization could improve production efficiency of direct-seeding rape in no-tillage rice stubble field.%稻茬油菜免耕直播技术可减少用工,降低冬闲田面积,但其产量常低于翻耕栽培模式.为探讨免耕直播油菜产量制约因素,本研究在盆栽试验条件下测定各品系苗期根冠比、抗旱性、耐渍性及氮肥利用率等生理指标,

  17. Loss of a child - resources

    Science.gov (United States)

    Child death - resources; Resources - loss of a child ... The following organizations are good resources for information on the loss of a child: The Compassionate Friends -- www.compassionatefriends.org Bereaved Parents of the USA -- www.bereavedparentsusa. ...

  18. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... Follow us on Twitter Noise Manufacturing Construction SafeInSound Noise and Hearing Loss on the NIOSH Science Blog ... Topics Publications and Products Programs Contact NIOSH NIOSH NOISE AND HEARING LOSS PREVENTION Recommend on Facebook Tweet ...

  19. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is ... I find additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound ...

  20. Determination of heat losses in the Cerro Prieto, Baja California, geothermal field steam transportation network based on the thermal insulation condition of the steam pipelines; Determinacion de perdidas de calor en la red de transporte de vapor del campo geotermico de Cerro Prieto, Baja California, con base en el estado fisico del aislamiento termico de vaporductos

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Garcia Gutierrez, Alfonso; Martinez Estrella, Juan Ignacio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; Canchola Felix, Ismael; Jacobo Galvan, Paul; Miranda Herrera, Carlos; Mora Perez, Othon [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)

    2011-07-15

    In Cerro Prieto Geothermal Field (CPGF), the steam from producing wells is transported to power plants through a large and complex system of pipes thermally insulated with a 2 inches thick mineral wool or a fiber glass layer and an external aluminum or iron cover. The insulation material has been exposed to weather conditions during the field operation and has suffered density and thickness changes. In some cases the insulation has been lost completely, increasing heat transfer from the pipes to the environment. This paper analyzes the impact of the conditions of thermal insulation on heat losses in the CPGF steam-pipeline network. The heat losses are calculated by applying an iterative method to determine the surface temperature based on a heat balance calculated from the three basic mechanisms of heat transfer: conduction, convection, and radiation. Finally, using length and diameter data corresponding to the condition of the thermal insulation of each pipeline-and field operation data, the overall heat losses are quantified for steam lines throughout the pipeline network in the field. The results allow us to evaluate the magnitude of the heat losses in comparison with the overall energy losses occurring during steam transport from wells to the power plants. [Spanish] En el Campo Geotermico de Cerro Prieto (CGCP), BC, el transporte de vapor desde los pozos hasta las plantas generadoras de electricidad se lleva a cabo mediante un extenso y complejo sistema de tuberias que tipicamente se encuentran aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion mecanica de aluminio o hierro galvanizado. Debido a la exposicion a las condiciones meteorologicas a traves del tiempo de operacion del campo, el aislamiento ha experimentado cambios en su densidad y espesor y en ocasiones se ha perdido por completo, lo cual repercute en una mayor transferencia de calor de las tuberias hacia el medio ambiente

  1. Hypothyroidism and pregnancy loss

    DEFF Research Database (Denmark)

    Andersen, Stine Linding; Olsen, Jørn; Laurberg, Peter

    2016-01-01

    BACKGROUND: Hypothyroidism is a common endocrine disease. The frequency of pregnancy loss in women with known hypothyroidism as opposed to women with a later diagnosis of hypothyroidism has not been evaluated and compared with other common endocrine diseases. DESIGN: Population-based cohort study...... using Danish nationwide registers. PARTICIPANTS: All pregnancies in Denmark, 1997-2008, resulting in live birth (n=732,533), spontaneous abortion (n=112,487) or stillbirth (n=2,937) were identified together with information on maternal hypothyroidism, hyperthyroidism and diabetes. METHODS: Cox model...... was used to estimate adjusted hazard ratio (aHR) with 95% confidence interval (95%CI) for spontaneous abortion and stillbirth, reference: no hypo- or hyperthyroidism or diabetes (n=824,310). RESULTS: We identified 4,951 pregnancies where maternal hypothyroidism was diagnosed before the pregnancy (group 1...

  2. Change, Gain and Loss

    Institute of Scientific and Technical Information of China (English)

    Fu Mengzi

    2006-01-01

    @@ Five years have passed since the September 11 terrorist attacks occurred. America's counter-terrorism campaign is still on the way.Besides the momentary monumental significance of the fifth anniversary, five years is still too short in regard to the long-term counter-terrorism campaign. Yet, America's president's tenure is eight years at best; most of Bush's presidency time has passed. Five years ago, the U. S. encountered the most serious terrorist attack; the whole nation formed a consensus that counter-terrorism is its utmost priority. President Bush once enjoyed a support rate as high as 90% for over 16 months. But five years later, the trend changes. People can not help but ask: what are the gains and losses of the Republican Party in dealing with national security affairs?

  3. Relative Information Loss - An Introduction

    CERN Document Server

    Geiger, Bernhard C

    2012-01-01

    We introduce a relative variant of information loss to characterize the behavior of deterministic input-output systems. We show that the relative loss is closely related to Renyi's information dimension. We provide an upper bound for continuous input random variables and an exact result for a class of functions (comprising quantizers) with infinite absolute information loss. A connection between relative information loss and reconstruction error is investigated.

  4. Methodology for Evaluating Water Losses

    OpenAIRE

    Mindaugas Rimeika; Anželika Jurkienė

    2013-01-01

    A reduction in water losses is significant for improving the efficiency of water supply systems and sustainable water use. The major part of water supply companies does not have enough experience in reducing water losses; therefore, a lack of information about practically applied measures for reducing water losses can be noticed. The article presents a method for determining water losses implemented under real conditions. The conducted research defines minimum night-time water consumption for...

  5. Losses compensation; Compensation des pertes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    One mission of RTE (Electric Power Transportation), is to watch over the losses compensation resulting from the power transport on the electric power network. Since january 2001, RTE makes good the electric losses by the purchase of energy. To choose the marketers, a consultation has been realized by RTE. This document presents the rules concerning these losses compensation. (A.L.B.)

  6. Loss Aversion and Individual Characteristics

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Fosgerau, Mogens

    2011-01-01

    Many studies have shown that loss aversion affects the valuation of non-market goods. Using stated choice data, this paper presents an empirical investigation of how individual-level loss aversion varies with observable personal characteristics and with the choice context. We investigate loss...

  7. Breast Cancer and Bone Loss

    Science.gov (United States)

    ... Balance › Breast Cancer and Bone Loss Fact Sheet Breast Cancer and Bone Loss July, 2010 Download PDFs English ... JoAnn Pinkerton, MD What is the link between breast cancer and bone loss? Certain treatments for breast cancer ...

  8. Sensorineural hearing loss in children.

    LENUS (Irish Health Repository)

    Wormald, R

    2010-02-01

    The objective of the study was to examine the aetiology of sensorineural hearing loss (SNHL) in a paediatric population presenting to the National Centre of Medical Genetics. A retrospective chart review from 1998 to 2006. One hundred and twenty nine children were investigated for SNHL. The average age of diagnosis of hearing loss was 36 months. The degree of hearing loss was mild in 8 children, moderate in 33 children, severe in 31 children and profound in 57 children. Eighty-five children (66%) were diagnosed with a hereditary hearing loss, 11 (8%) children had an acquired hearing loss and no cause found in 33 (26%) children. This is the first report of the causes of hearing loss in Irish children. The mean age of diagnosis in our cohort is high and emphasises the need for a neonatal screening programme. There remains a number of children for whom the cause of hearing loss remains unknown.

  9. Study on Radiation Field Caused by Proton Beam Loss in High Intensity Heavy-ion Accelerator%强流重离子加速器中由于质子束流损失引起的次级辐射场计算研究

    Institute of Scientific and Technical Information of China (English)

    庞成果; 苏有武; 徐俊奎; 李武元; 姚泽恩

    2015-01-01

    The second radiation field outside the vacuum tube caused by proton beam loss in high intensity heavy‐ion accelerator facility (HIAF) with Monte Carlo method was calculated .The energy of proton beam is within 50 MeV to 12 GeV .The basic problems such as second particle yield ,energy spectrum and angular distribution were also discussed .T hese results are beneficial to selecting the detector type and its location and determining its dynamic range for beam loss detector ,as well as to building the beam loss monitor system .Furthermore ,they are meaningful in some way for the radia‐tion protection of accelerator .%本文利用蒙特卡罗方法计算了强流重离子加速器中质子能量在50 M eV~12 GeV能量范围内由于束流损失引起的真空管壁外的次级辐射场,分别就次级粒子的产额、能谱及角分布等方面进行了基本研究。本文的研究结果在束流损失探测器的选择、安装位置以及动态范围的确定上有着重要的参考价值,对于束流损失监测系统的建立有着极为重要的意义。同时,对于加速器的辐射防护问题也有一定的参考价值。

  10. Vertigo and hearing loss.

    Science.gov (United States)

    Newman-Toker, David E; Della Santina, Charles C; Blitz, Ari M

    2016-01-01

    Symptoms referable to disorders affecting the inner ear and vestibulocochlear nerve (eighth cranial nerve) include dizziness, vertigo, tinnitus, and hearing loss, in various combinations. Similar symptoms may occur with involvement of the central nervous system, principally the brainstem and cerebellum, to which the vestibular and auditory systems are connected. Imaging choices should be tailored to patient symptoms and the clinical context. Computed tomography (CT) should be used primarily to assess bony structures. Magnetic resonance imaging (MRI) should be used primarily to assess soft-tissue structures. Vascular imaging by angiography or venography should be obtained when vascular lesions are suspected. No imaging should be obtained in patients with typical presentations of common peripheral vestibular or auditory disorders. In current clinical practice, neuroimaging is often overused, especially CT in the assessment of acute dizziness and vertigo in the emergency department. Despite low sensitivity for ischemic strokes, CT is often used to rule out neurologic causes. When ischemic stroke is the principal concern in acute vestibular presentations, imaging should almost always be by MRI with diffusion-weighted images, rather than CT. In this chapter, we describe recommended strategies for audiovestibular imaging based on patient symptoms and signs. PMID:27430449

  11. Analysis of AC loss in superconducting power devices calculated from short sample data

    NARCIS (Netherlands)

    Rabbers, J.J.; Haken, ten B.; Kate, ten H.H.J.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile

  12. Reducing catalytic converter pressure loss

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This article examines why approximately 30--40% of total exhaust-system pressure loss occurs in the catalytic converter and what can be done to reduce pressure loss. High exhaust-system backpressure is of concern in the design of power trains for passenger cars and trucks because it penalizes fuel economy and limits peak power. Pressure losses occur due to fluid shear and turning during turbulent flow in the converter headers and in entry separation and developing laminar-flow boundary layers within the substrate flow passages. Some of the loss mechanisms are coupled. For example, losses in the inlet header are influenced by the presence of the flow resistance of a downstream substrate. Conversely, the flow maldistribution and pressure loss of the substrate(s) depend on the design of the inlet header.

  13. LHC beam loss pattern recognition

    CERN Document Server

    Marsili, A; Puzo, P

    2011-01-01

    One of the systems protecting CERN’s Large Hadron Collider (LHC) is the Beam Loss Monitoring system (BLM). More than 3600 monitors are installed around the ring. The beam losses are permanently integrated over 12 different time intervals (from 40 microseconds to 84 seconds). When any loss exceeds the thresholds defined for the integration window, the beam is removed from the machine. Understanding the origin of a beam loss is crucial for machine operation, as it can help to avoid a repetition of the same scenario. The signals read from given monitors can be considered as entries of a vector. This article presents how a loss map of unknown cause can be decomposed using vector based analysis derived from well-known loss scenarios. The algorithms achieving this decomposition are described, as well as the accuracy of the results.

  14. Alpha particle losses from Tokamak Fusion Test Reactor deuterium-tritium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Darrow, D.S.; Zweben, S.J. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Batha, S. [Fusion Physics and Technology, Torrance, CA (United States)

    1996-01-01

    Because alpha particle losses can have a significant influence on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohydrodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to collective instabilities driven by alphas. Ion Bernstein waves can drive large losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario.

  15. Alpha particle losses from Tokamak Fusion Test Reactor deuterium-tritium plasmas

    International Nuclear Information System (INIS)

    Because alpha particle losses can have a significant influence on tokamak reactor viability, the loss of deuterium-tritium alpha particles from the Tokamak Fusion Test Reactor (TFTR) has been measured under a wide range of conditions. In TFTR, first orbit loss and stochastic toroidal field ripple diffusion are always present. Other losses can arise due to magnetohydrodynamic instabilities or due to waves in the ion cyclotron range of frequencies. No alpha particle losses have yet been seen due to collective instabilities driven by alphas. Ion Bernstein waves can drive large losses of fast ions from TFTR, and details of those losses support one element of the alpha energy channeling scenario

  16. Drug-induced hair loss.

    Science.gov (United States)

    2016-05-01

    Hair loss can have major psychological consequences. It can be due to a wide variety of causes, including hormonal disorders, dietary factors, infections, inflammation, trauma, emotional factors, and cancer. Drugs can also induce hair loss, by interacting with the hair growth cycle. Drug-induced hair loss may be immediate or delayed, sudden or gradual, and diffuse or localised. It is usually reversible after drug discontinuation. The drugs most often implicated in hair loss are anticancer agents, interferon, azole antifungals, lithium, immunosuppressants, and many other drugs belonging to a variety of pharmacological classes.

  17. Feather loss in laying hens

    OpenAIRE

    Hristov Slavča; Mitrović Sreten; Todorović Mirjana; Đermanović Vladan; Cvetković Ivica

    2006-01-01

    The paper examined the incidence of different forms of feather loss and cannibalism in laying hens aged 74 weeks following moulting and in laying hens following exploitation for a period of one year. The forms of feather loss were considered in detail through a repeated examination of video recordings and they were sorted according to localization - to feather loss on the ventral part of the neck, on the dorsal part of the neck, and on the back between the wings. Feather loss on the ventral p...

  18. THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

    Institute of Scientific and Technical Information of China (English)

    徐华; 王艳

    2004-01-01

    Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1000Hz, rotating speed is from 60rpm to 1200rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shaft's speed.

  19. Characteristic of Ion loss as determined by hybrid simulations

    Science.gov (United States)

    Brecht, Stephen H.; Ledvina, Stephen

    2016-10-01

    One of the major objectives of the MAVEN mission is to determine the loss rate of oxygen ions from the atmosphere of Mars. It is thought that the oxygen ion loss represents a conduit for the loss of water from Mars. However, the actual measurements and estimates of global loss rates are very difficult because one needs an average over many orbits and full coverage of the loss regions of Mars; something that MAVEN will only accomplish with an extended mission. In the meantime global kinetic simulations are an avenue to gain further insight into the loss process and perhaps offer insight into the data analysis that will be performed on the MAVEN data. Hybrid particle codes provide self-consistent simulations of the ion dynamics occurring when the solar wind interacts with Mars.This paper reports the results of HALFSHEL hybrid code simulations of the solar wind interaction with Mars and the subsequent loss of oxygen ions in the form of O+ and O2+. Four simulations were performed representing different orientations of the crustal magnetic fields with the subsolar regions using a solar EUV flux representative of the moderate solar activity experienced by MAVEN. Loss rates will be presented as will evaluations of the distribution functions of the various loss ion species as accumulated at roughly 2 Rm for each of the four simulations. The results will be presented as faces on a box surrounding Mars so that one can evaluate regions such as that of the measured plasma plume. The plume feature has now been measured and is often seen in simulations. Finally, the losses and the subsequent velocity distributions will be compared between the various crustal magnetic field orientations.In summary, results from the HALFSHEL hybrid code will be presented. These results will address characteristics of the oxygen ions lost from Mars as a function of crustal magnetic field orientation. Further, they will be compared with respect to the regions surrounding Mars and the associated

  20. Hinge-Loss Markov Random Fields and Probabilistic Soft Logic

    OpenAIRE

    Bach, Stephen H.; Broecheler, Matthias; Huang, Bert; Getoor, Lise

    2015-01-01

    A fundamental challenge in developing high-impact machine learning technologies is balancing the ability to model rich, structured domains with the ability to scale to big data. Many important problem areas are both richly structured and large scale, from social and biological networks, to knowledge graphs and the Web, to images, video, and natural language. In this paper, we introduce two new formalisms for modeling structured data, distinguished from previous approaches by their ability to ...

  1. AC loss calculation of central solenoid model coil

    International Nuclear Information System (INIS)

    The AC loss of Central Solenoid Model Coil of ITER is calculated in order to be able to determine the allowable excitation current shape in time with respect to the available cooling capacity at liquid helium temperature. In Part A the theory is summarized essential to present calculation. This covers a semianalytical integral formulation to calculate the magnetic field distribution in the cross-section of a coil and also 2D and 3D differential formulations for eddy current calculation of jackets and structural steel components, respectively. In Part B the conditions and results of calculation are described in detail. Losses are calculated separately in different components. Also the different types of losses are separated, and only one of the followings is considered in the same time; eddy current loss, ferromagnetic hysteresis loss, superconducting hysteresis loss, coupling loss. The followings are concluded. The coupling loss was found to be the largest 83% of the total AC loss supposing 50 msec characteristic time constant. Also significant amount of heat is generated in structural steels, cooling is required for stainless steel structural components. The loss of joints is not large, however concentrated, therefore joints should receive attention. Specially Lap-type joints are critical components. The eddy current and coupling power losses can be significantly decreased by increasing the ramp-up time since they are proportional to the square of flux change rate, while superconducting and ferromagnetic hysteresis power losses decrease linearly with decreasing flux change rate. Joule losses are produced in joints even after the energizing process of the magnet, when it is driven by a constant excitation current. This propose us to keep the time of full power operation short. (J.P.N.)

  2. Scannerless laser range imaging using loss modulation

    Science.gov (United States)

    Sandusky, John V.

    2011-08-09

    A scannerless 3-D imaging apparatus is disclosed which utilizes an amplitude modulated cw light source to illuminate a field of view containing a target of interest. Backscattered light from the target is passed through one or more loss modulators which are modulated at the same frequency as the light source, but with a phase delay .delta. which can be fixed or variable. The backscattered light is demodulated by the loss modulator and detected with a CCD, CMOS or focal plane array (FPA) detector to construct a 3-D image of the target. The scannerless 3-D imaging apparatus, which can operate in the eye-safe wavelength region 1.4-1.7 .mu.m and which can be constructed as a flash LADAR, has applications for vehicle collision avoidance, autonomous rendezvous and docking, robotic vision, industrial inspection and measurement, 3-D cameras, and facial recognition.

  3. Genes and Syndromic Hearing Loss.

    Science.gov (United States)

    Keats, Bronya J. B.

    2002-01-01

    This article provides a description of the human genome and patterns of inheritance and discusses genes that are associated with some of the syndromes for which hearing loss is a common finding, including: Waardenburg, Stickler, Jervell and Lange-Neilsen, Usher, Alport, mitochondrial encephalomyopathy, and sensorineural hearing loss. (Contains…

  4. The Stigma of Hearing Loss

    Science.gov (United States)

    Wallhagen, Margaret I.

    2010-01-01

    Purpose: To explore dimensions of stigma experienced by older adults with hearing loss and those with whom they frequently communicate to target interventions promoting engagement and positive aging. Design and Methods: This longitudinal qualitative study conducted interviews over 1 year with dyads where one partner had hearing loss. Participants…

  5. Capital loss in China's agriculture

    Institute of Scientific and Technical Information of China (English)

    Cheng Peng

    2004-01-01

    China's agriculture has contributed a lot to industrialization but it has suffered a long-run and severe capital loss.This paper provides an estimation model of capital loss in agriculture and gives some explanation in marginal approach.With an eye to a balanced and sustainable economy development, it is high time for government to do something for it.

  6. 10-minute consultation Olfactory loss

    Institute of Scientific and Technical Information of China (English)

    E Ofo; B O'Reilly; A O'Doherty

    2007-01-01

    @@ A 65 year old man presents with loss of smell and altered taste,affecting his appetite and food intake. He had an upper respiratory tract infection before the onset of symptoms nine months ago.Initially, normal odours were distorted, followed by a constant foul smell for three months, and then complete loss of smell.

  7. Nature's loss, Immunologists gain?

    Science.gov (United States)

    Aluvihare

    2000-01-01

    Nature Reviews Molecular Cell Biology Nature Publishing Group (2000). ISSN 1471-0072. Monthly First there was Annual Reviews, then came the monthly Elsevier Trends Journals, both of which try to identify hot topics in their chosen fields. The Current Opinion journals followed several years later, and Current Opinion in Cell Biology is presently one of the highest 'impact factor' review journals, with a distinguished board of editors and advisors and a systematic approach to regular coverage of the major fields of cell biology. Important topics are visited once a year, whether or not something specially exciting happened in the last 12 months. Add to this list Seminars in Cell and Developmental Biology, the FASEB journal and the countless minireviews in 'real' journals, and you begin to wonder how anyone finds any time for doing experiments, or indeed reading the primary literature. So, into this already crowded field arrive three important newcomers: Nature Reviews in Molecular Cell Biology, Genetics, and Neurosciences, of which the first two will probably interest readers of Journal of Cell Science the most. Backed by the name and money of Nature and edited by experienced Nature staff, it is hard to see how these publications can possibly do other than succeed with writers and readers alike. What's inside the first issue? The cover of Nature Reviews in Molecular Cell Biology presents a 3-colour montage of a blue cell nucleus surrounded by splotches of green GPI-anchored GFP overlaid by orange actin stress fibres that seem to come from somewhere else. This image trails a comprehensive review from Kai Simons and Derek Toomre about Lipid Rafts. There are another five major review articles: calcium puffs and sparks, rings around DNA, HIV inhibitors, kinesin and the circadian clock provide a rich and varied mix of topics from authors who know what they're talking about. Surrounding this core is an entertaining mixture of 'highlights' at the front: news and views about

  8. Some ethical reflections on weight-loss diets

    OpenAIRE

    ERTİN, Hakan; ÖZALTAY, Bülent

    2011-01-01

    To assess how weight-loss diets tend to move away from the authority of conventional medicine and become a field of abuse. Endocrinologists and specialists on metabolic diseases are rarely called upon to speak about obesity, whereas physicians from unrelated fields or nonphysicians frequently appear in the media. Materials and methods: The literature related with the field was reviewed and interpreted from an ethical perspective. Results: It is presented medically doubtful solutions via ...

  9. 地形和气候对中国山地森林带界线的影响%Effect of Regional Topographic and Climatic Factors on Limits of Altitudinal Forest Belts

    Institute of Scientific and Technical Information of China (English)

    孙然好; 张百平

    2013-01-01

    The division of vegetation zones is an old and highly emphasized topic in both botany and geography. High mountains are characterized by different vegetation types at different elevations. Altitudinal vegetation belts are bounded by relatively narrow boundaries. Investigation and identification of altitudinal vegetation belts is significant in ecological and geographical studies due to extremely complex environment and diverse vegetation types in mountains. Altitudinal forest belts (AFBs) are significantly impacted by topographic and climatic factors. The climatic data used in this study were obtained from Chinese Ecosystem Research Network (CERN) between 1960 and 2000. After analyzing the significance of the 13 climatic factors in 31 base belts, we obtained three dominant principal components (PCs) designated as temperature variation index in winter (WTVI), temperature variation index in summer (STVI), and drought index (DI). WTVI decreased from South to North China, whereas STVI was high in South China and Tibetan Plateau. DI increased from the southwest to the northwest of China. Next, 28 AFB data were collected from published references. Multivari-ate regression analysis was used to quantify the relationship between AFB characteristics and topographic and climatic PCs. Results show that the base elevation of a mountain has the significant contribution to lower limits of AFBs (39.67%), whereas the relative elevation of a mountain has the significant contribution to upper limits of AFBs (39.34%). The climatic factors have similar contributions to variations in upper limits, lower limits, and width of AFBs. Among the three climatic PCs, STVI has the most contribution to variations of AFBs, followed by WTVI and DI. This paper quantifies the relative contributions of topographic and climatic factors to variations in AFBs at regional scales, and could potentially be used to evaluate and model the AFB distributions in other mountainous regions at regional or global

  10. 三峡库区不同垂直带森林土壤大孔隙染色实验%Forest Soil Macropore of Different Altitudinal Zones with Dye Tracing Method in Three Gorges Reservoir Area

    Institute of Scientific and Technical Information of China (English)

    刘目兴; 王文德; 张海林; 杜文正

    2012-01-01

    降雨过程中森林土壤大孔隙内优先流的发生,是森林植被调蓄径流和保持水土的主要方式.利用染色示踪法,对三峡库区宜昌大老岭-邓村地区不同垂直带内森林土壤大孔隙特征进行了实验研究.结果表明,山地植被-土壤类型的梯度变化使不同垂直带内土壤大孔隙数量差异显著,在土壤垂直剖面内呈现不同分布模式.亚高山阔叶林覆盖的山地棕壤下,土壤剖面染色面积比达62.3%,染色区域主要集中在根系发达的腐殖质层,染料下渗深度较浅.低山针叶林黄壤剖面染色比例低于亚高山阔叶林棕壤,但染料下渗深度较深可达69.5 cm,腐殖质层、淋溶淀积层和母质层间染色比例无显著差异.中山灌丛幼林黄棕壤剖面染色比例和染料下渗深度较小,腐殖质层染色比例显著高于淋溶淀积层,母质层几乎无染色现象.与森林土壤相比,低山弃耕坡地的染料下渗深度和染色面积比显著减小,染色区域集中在耕作表层.植物根孔、母质裂隙、土壤发育程度和土地耕作是造成山地不同垂直带间土壤大孔隙结构差异的主要因素.%Preferential flow in soil macropore was principle formation of forest function in runoff adjustment and soil and water conservation. Through dye tracing and image analysis, we studied soil macropore characteristics of different altitudinal zones in Three Gorges Reservoir area from Dalaoling to Dengcun of Yichang City. The results indicated that the number of soil macropore varied greatly at different altitudinal zones, and the distribution of dyed area in soil profile also show different modes, which were caused by the vertical gradient changes of forest vegetation and soil type. Under the mountain brown earth covered with subalpine broad-leaf forest, the ratio between dyeing area and total soil profile is 62. 3% ,but dyed zone concentrate on the Humus layer with more roots,and the dyed depth is shallow. The dyeing

  11. Carbon and nitrogen stable isotopes of leaves, litter and soils of the coastal Atlantic Forest of Southeast Brazil along an altitudinal range

    Science.gov (United States)

    Lins, S. M.; Della Coletta, L.; Ravagnani, E.; Gragnani, J. G.; Antonio, J.; Mazzi, E. A.; Martinelli, L. A.

    2012-12-01

    In this study the carbon and nitrogen concentrations, and stable carbon (δ13C) and stable nitrogen (δ15N) isotopic composition were determined in samples of Fabaceae and non Fabaceae leaves, litter, and soil samples in two different altitudes (Lowland and Montane Forests) of the coastal Atlantic Forest situated in the Southeast region of Brazil. In both altitudes there were two main differences between Fabaceae and non Fabaceae specimens. Fabaceae had a higher foliar nitrogen content and lower foliar δ15N than non Fabaceae specimens. As a consequence it seems that most of the Fabaceae specimens are fixing nitrogen from the atmosphere in both altitudes. This fact is contrary to most of other studies that found that most Fabaceae are not fixing nitrogen in tropical forests. We speculate that the main reason that Fabaceae are actively fixing nitrogen in the coastal Atlantic Forest is the steepness of the terrain that leads to frequent landslides, causing frequent disturbances of the nitrogen cycle, fostering nitrogen fixation. The main difference between the Lowland and the Montane Forest plots was the higher δ15N in the former in comparison with the later. We speculated that this difference is caused by larger losses of nitrogen by denitrification and riverine output, leading an enriched 15N substrate.

  12. Trends in global earthquake loss

    Science.gov (United States)

    Arnst, Isabel; Wenzel, Friedemann; Daniell, James

    2016-04-01

    Based on the CATDAT damage and loss database we analyse global trends of earthquake losses (in current values) and fatalities for the period between 1900 and 2015 from a statistical perspective. For this time period the data are complete for magnitudes above 6. First, we study the basic statistics of losses and find that losses below 10 bl. US satisfy approximately a power law with an exponent of 1.7 for the cumulative distribution. Higher loss values are modelled with the General Pareto Distribution (GPD). The 'transition' between power law and GPD is determined with the Mean Excess Function. We split the data set into a period of pre 1955 and post 1955 loss data as in those periods the exposure is significantly different due to population growth. The Annual Average Loss (AAL) for direct damage for events below 10 bl. US differs by a factor of 6, whereas the incorporation of the extreme loss events increases the AAL from 25 bl. US/yr to 30 bl. US/yr. Annual Average Deaths (AAD) show little (30%) difference for events below 6.000 fatalities and AAD values of 19.000 and 26.000 deaths per year if extreme values are incorporated. With data on the global Gross Domestic Product (GDP) that reflects the annual expenditures (consumption, investment, government spending) and on capital stock we relate losses to the economic capacity of societies and find that GDP (in real terms) grows much faster than losses so that the latter one play a decreasing role given the growing prosperity of mankind. This reasoning does not necessarily apply on a regional scale. Main conclusions of the analysis are that (a) a correct projection of historic loss values to nowadays US values is critical; (b) extreme value analysis is mandatory; (c) growing exposure is reflected in the AAL and AAD results for the periods pre and post 1955 events; (d) scaling loss values with global GDP data indicates that the relative size - from a global perspective - of losses decreases rapidly over time.

  13. Pediatric Sudden Sensorineural Hearing Loss.

    Science.gov (United States)

    Kizilay, Ahmet; Koca, Çiğdem Firat

    2016-06-01

    Sudden sensorineural hearing loss is defined as sudden unilateral or bilateral sensorineural hearing loss with at least 30 dB decrease in threshold in 3 contiguous test frequencies occurring over 72 hours or less. It is rare among children. The mechanism of the process and prognosis of the disorder remains unclear. The current incidence of sudden sensorineural hearing loss among pediatric population is unknown. The authors carried out a retrospective chart analysis of patients under 15 years of age from 2004 to 2015, who consulted to the Otolaryngology Head and Neck Surgery Department of Inonu University Medical Faculty. Age, sex, number of affected ear and side, audiometric evaluations, medical follow-up, treatment method, duration of treatment recovery, associated complaints; tinnitus and/or vertigo, presence of mumps disease were recorded for each patient. A 4-frequency pure-tone average (500, 1000, 2000, and 4000 Hz) was calculated for each ear. Complete recovery, defined as some hearing level compared with the nonaffected ear, was observed in 3 patients (21.4 %) and there was no partial hearing recovery. The hearing loss of 11 patient remained unchanged after prednisolone treatment. Two of the 11 patients had bilaterally total sensorineural hearing loss and evaluated as appropriate for cochlear implantation. Sex of patient and laterality of hearing loss were not correlated with hearing recovery. Sensorineural hearing loss among pediatrics has been the issue of otolaryngologists. The incidence, etiology, and treatment methods should be more studied.

  14. Optimum intermediate fibers for reducing interconnection loss: exact solution.

    Science.gov (United States)

    Yablon, Andrew D; Sumetsky, M

    2007-03-15

    We derive an exact analytical solution for a transmission line of N single-mode intermediate optical fibers that minimize the interconnection loss between any two dissimilar fiber modes that are well described by that paraxial scalar wave equation. Our solution shows that N optimum intermediate fibers reduce the original interconnection loss by a factor of least 1/(N+1) and that the total interconnection loss is only a function of N and the original direct interconnection loss. Our solution is not restricted to axisymmetric fibers or mode fields and therefore could be useful for reducing the interconnection loss between microstructured optical fibers, between certain slab waveguides, or between fibers and optical sources or detectors.

  15. Minor Losses During Air Flow into Granular Porous Media

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe; Minelgaite, Greta; Bentzen, Thomas Ruby;

    2013-01-01

    Pressure gradients during uniform fluid flow in porous media are traditionally assumed to be linear. Thus pressure loss across a sample of porous medium is assumed directly proportional to the thickness of the sample. In this study, measurements of pressure gradients inside coarse granular (2 – 18...... mm particle size) porous media during steady gas flow were carried out. The results showed that pressure variation with distance in the porous media were nonlinear near the inlet (where pressure gradients were higher) but became linear at greater distances (with a lower gradient). This indicates...... that pressure loss in porous media consists of two components: (1) a linear pressure gradient and (2) an initial pressure loss near the inlet. This initial pressure loss is also known from hydraulics in tubes as a minor loss and is associated with abrupt changes in the flow field such as narrowings and bends...

  16. Measurement of AC losses in different former materials

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa;

    1998-01-01

    candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible......A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...... we aim at investigating the eddy current losses of commonly used former materials. A one layer cable conductor was wound on a glass fibre reinforced polymer (GRFP) former. By inserting a variety of materials into this, it was possible to measure the eddy current losses of each of the former...

  17. Heat losses estimation associated with the physical state of the thermal insulation of pipes vaporductos network in Cerro Prieto geothermal field; Estimacion de perdidas de calor asociadas al estado fisico del aislamiento termico de las tuberias de la red de vaporductos del campo geotermico Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Martinez Estrella, Juan Ignacio; Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; jime@iie.org.mx; aggarcia@iie.org.mx; Canchola Felix, Ismael; Miranda Herrera, Carlos; Jacobo Galvan, Paul [Campo Geotermico de Cerro Prieto, Comision Federal de Electricidad, Mexicali, B.C. (Mexico)

    2010-11-15

    The Cerro Prieto Geothermal Field (CPGF) steam transportation network is constituted by 140 km of pipes with diameters ranging from 8 to 48 inches, which transport the steam of 165 producing wells to 13 power plants which have a total installed capacity of 720 MWe. Originally, the pipes are thermally insulated with a mineral wool or fiber glass layer and an external aluminum or iron cover. Due to the insulation material has been exposed to weather conditions during the field operation it shows nowadays different grades of wear-out, or even it is lacking in some parts of the network, causing higher heat losses from the pipes to the environment. In this work, the magnitude of the heat losses related with the present condition of the thermal insulation throughout the pipeline network is assessed. This involved determining the longitude and diameter, as well as the insulation condition of each single pipeline section, and the calculation of the heat transfer coefficients for the different thermal insulation conditions defined for this study. [Spanish] La red de transporte de vapor del campo geotermico Cerro Prieto (CGCP) esta constituida por aproximadamente 140 km de tuberias de 8 a 48 pulgadas de diametro, las cuales conducen el vapor producido por 165 pozos hacia 13 plantas generadoras, cuya capacidad instalada es de 720 MWe. Originalmente, estas tuberias son aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion exterior de aluminio o hierro. Debido principalmente al impacto de las condiciones meteorologicas durante el tiempo de operacion del campo, en algunas porciones de la red el aislante presenta actualmente distintos grados de deterioro, o incluso se encuentra ausente, lo cual se traduce en una mayor perdida de calor desde las tuberias hacia el medio ambiente. En el presente trabajo se evalua la magnitud de las perdidas de calor asociadas al estado fisico del aislamiento termico de las

  18. Stationary bubbles: information loss paradox?

    CERN Document Server

    Domènech, Guillem

    2016-01-01

    The main purpose of this work is to build classically stationary bubbles, within the thin-shell formalism, which are unstable under quantum effects; they either collapse into a black hole or expand. Thus, the final state can be thought of a superposition of geometries. We point out that, from a quantum mechanical point of view, there is no issue with a loss of information in such configuration. A classical observer sees a definite geometry and, hence, finds an effective loss of information. Although it does not cover all possible cases, we emphasise the role of semi-classical gravitational effects, mediated by instatons, in alleviating/solving the information loss paradox.

  19. Hearing loss in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Pemmaiah K.D

    2011-10-01

    Full Text Available Background: The complex arrangement of inner ear makes it potential target of hyperglycaemic damage. A study was conducted to identify the probable occurrence of hearing loss as a complication of Diabetes Mellitus (DM.Aims and objective:· To assess the hearing loss in type 2 diabetic patients and correlate with age, duration of diabetes, HbA1C.· To correlate hearing loss with nerve conduction study.Design: Cross sectional study was done involving randomly 110 Type 2 DM patients. Data regarding their age and duration of diabetes was collected. Pure tone Audiometry and Nerve conduction study was done. HbA1c level determined. Data statistically analysed using Pearson correlation coefficient.Results: Out of 110 patients 48 patients (43.6% had bilateral Sensorineural hearing in higher frequency (2000hz, 4000hz. Among them Severe hearing loss (71 dB to 90dB was seen in 7 patients (6.36%, moderately severe hearing loss (61dB to 70dB in 16 patients (14.54% and moderate hearing loss(30dB to 60 dB in 25 patients (22.7%. Among 47 patients who had diabetes for more than 10 years, 29 patients (61.7% showed at least mild hearing loss. Duration of DM and sensorineural hearing loss at 2000Hz and 4000Hz showed statistically significant correlation (Pearson coefficient r= 0.561 and r= 0.727 respectively at 0.01 level. In other frequencies no significant correlation was found. Coefficient of determination was r2=0.31(31% and r2=0.52(52% respectively between duration of DM and hearing loss at 2000Hz and 4000Hz. The correlation of hearing loss in lower frequency with HbA1c did not show any statistical significance. However HbA1c and hearing loss in higher frequency (2000 hz and 4000hz showed statistically significant correlation (Pearson coefficient r= 0.282 and r= 0.385 respectively. The correlation of hearing loss with Nerve conduction study did not show any statistical significance.

  20. Visual loss with papilledema in Guillain-Barre syndrome.

    Directory of Open Access Journals (Sweden)

    Kharbanda P

    2002-10-01

    Full Text Available Papilledema and raised intracranial pressure have been reported in association with Guillain-Barre syndrome. Papilledema is usually asympotomatic or associated with mild visual field defects, without any visual loss. The cerebrospinal fluid protein is usually reported to be high. A case of a 35 year old lady is reported, who presented with headache, diplopia and progressive visual loss in both eyes and limb weakness with hyporeflexia. Optic fundus examination showed bilateral papilledema. She had features of pseudotumor cerebri. Nerve conduction studies were suggestive of polyradiculopathy. The unusual things in this case, were the profound visual loss normal cerebrospinal fluid profiles and the presentation of papilledema before the limb weakness.

  1. Beam loss control in the LINAC4 design

    CERN Document Server

    Stovall, J; Crandall, K

    2010-01-01

    The Linac4 DTL reference design has been modified to reduce the power consumption in tank 1 by modifying the accelerating field and phase law. In addition we have adopted an FFDD focusing lattice throughout to minimize expected losses resulting from alignment errors. We have observed, however, that this design suffers from decreasing transverse acceptance and a sensitivity to misalignments that causes any expected beam loss to occcur at the high energy end of the DTL. In this note we investigate two solutions to increase the acceptance, decrease its sensitivity to misalignments and eliminate the potential for a beam-loss “bottleneck” at 50 MeV.

  2. Simulations of Neutral Beam Ion Ripple Loss on EAST

    Institute of Scientific and Technical Information of China (English)

    李吉波; 丁斯晔; 吴斌; 胡纯栋

    2012-01-01

    Predictions on the ripple loss of neutral beam fast ions on EAST are investigated with a guiding center code, including both ripple and collisional effects. A 6% to 16% loss of neutral beam ions is predicted for typical EAST experiments, and a synergistic enhancement of fast ion loss is found for toroidal field (TF) ripples with collisions. The lost ions are strongly localized and will cause a maximum heat load of - 0.05 MW/m^2 on the first wall.

  3. Limitations on plasma acceleration due to synchrotron losses

    CERN Document Server

    Barletta, W A; Bonifacio, R; De Salvo, L

    1999-01-01

    In this letter we consider the effect of synchrotron radiation losses due to the betatron motion of the electron beam in its self-induced magnetic field in a plasma accelerator taking into account the charge neutralization factor. The most favorable case is where the plasma density is smaller than the beam density. The contrary regime is strongly disfavored by the synchrotron radiation loss for beams with characteristics for TeV energies. In both cases we find that upon increasing the plasma density the synchrotron losses kill the acceleration process, so that there are limitations on the maximum allowable plasma density.

  4. Secondary electron current loss in electron cooling devices

    Science.gov (United States)

    Sharapa, A. N.; Shemyakin, A. V.

    1994-12-01

    The efficiency of secondary electron capture in a recuperator with a longitudinal magnetic field is evaluated. To characterize this efficiency, the value of the collector secondary emission coefficient is introduced, for the calculation of which a simple formula is proposed. The effects determining the difference between the current losses in straight systems and devices with bending magnets are analyzed. It is experimentally shown that there is no unambiguous relation between the efficiency of the secondary electron capture by the collector and the current loss. The mechanism which determines the current loss in straight systems is suggested.

  5. Estimation of postfire nutrient loss in the Florida everglades.

    Science.gov (United States)

    Qian, Y; Miao, S L; Gu, B; Li, Y C

    2009-01-01

    Postfire nutrient release into ecosystem via plant ash is critical to the understanding of fire impacts on the environment. Factors determining a postfire nutrient budget are prefire nutrient content in the combustible biomass, burn temperature, and the amount of combustible biomass. Our objective was to quantitatively describe the relationships between nutrient losses (or concentrations in ash) and burning temperature in laboratory controlled combustion and to further predict nutrient losses in field fire by applying predictive models established based on laboratory data. The percentage losses of total nitrogen (TN), total carbon (TC), and material mass showed a significant linear correlation with a slope close to 1, indicating that TN or TC loss occurred predominantly through volatilization during combustion. Data obtained in laboratory experiments suggest that the losses of TN, TC, as well as the ratio of ash total phosphorus (TP) concentration to leaf TP concentration have strong relationships with burning temperature and these relationships can be quantitatively described by nonlinear equations. The potential use of these nonlinear models relating nutrient loss (or concentration) to temperature in predicting nutrient concentrations in field ash appear to be promising. During a prescribed fire in the northern Everglades, 73.1% of TP was estimated to be retained in ash while 26.9% was lost to the atmosphere, agreeing well with the distribution of TP during previously reported wild fires. The use of predictive models would greatly reduce the cost associated with measuring field ash nutrient concentrations. PMID:19643746

  6. ANALYZING SURFACE ROUGHNESS DEPENDENCE OF LINEAR RF LOSSES

    Energy Technology Data Exchange (ETDEWEB)

    Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB, W& amp; M College; Xu, Chen [JLAB, W& amp; M College

    2012-09-01

    Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

  7. Sudden hearing loss in children.

    Science.gov (United States)

    Ječmenica, Jovana; Bajec-Opančina, Aleksandra

    2014-08-01

    Sudden sensorineural hearing loss (SSHL) is defined as a unilateral or bilateral sensorineural hearing loss with at least 30 dB decrease in threshold in 3 contiguous test frequencies occurring over 72 hours or less. It is very rare in children. Sudden hearing loss is a symptom that suggests that there is a problem in the inner ear, surrounding structures, or the whole organism. The etiology and development of this disorder are still not fully understood. The literature contains numerous models of the pathogenesis of SSHL, with childhood SSHL having certain peculiarities. In practical terms, the multifactorial nature of SSHL is important in the choice of diagnostic methods and treatment methods. It is important to determine the cause and effect relationship between the underlying disease and hearing loss.

  8. Age-Related Hearing Loss

    Science.gov (United States)

    ... hearing loss. Here are the most common ones: Styles of hearing aids Source: NIH/NIDCD Hearing aids ... list of organizations, contact: NIDCD Information Clearinghouse 1 Communication Avenue Bethesda, MD 20892-3456 Toll-free Voice: ( ...

  9. Older Adults and Smell Loss

    Medline Plus

    Full Text Available ... can't detect them. Narrator: When smell loss does occur, it can be more than an unpleasant ... Dr. Cowart: You need to be sure, as does everyone, obviously, that you have functioning smoke detectors ...

  10. Coping with cancer -- hair loss

    Science.gov (United States)

    ... loss: stress and the underestimated psychosocial impact of telogen effluvium and androgenetic alopecia. Journal of Investigative Dermatology . ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  11. Job loss and broken partnerships

    DEFF Research Database (Denmark)

    Kriegbaum, Margit; Christensen, Ulla; Lund, Rikke;

    2008-01-01

    The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD).......The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD)....

  12. Age-differentiated QALI Losses

    OpenAIRE

    Praag, van, B.; Ferrer-i-Carbonell, A.

    2002-01-01

    In this paper we evaluate the QALY loss, which may be assigned to the prevalence of specific chronic illnesses and physical handicaps. The analysis is based on an individual self-rating health satisfaction question asked in the British Household Panel Survey data set. This question provides a natural cardinalization of health utility .Our method is a refinement of the method introduced by Cutler and Richardson (1997). We extend their approach in two directions. First, the health utility loss ...

  13. An energy loss straggling formula

    International Nuclear Information System (INIS)

    The analytical formulae for straggling widths were obtained solving Symon's equations for the second and third order central moments of the straggling distributions in non-relativistic approximation, enabling prediction of peak widths and asymmetry parameters of charged particle energy loss distributions for thick targets. The respective calculations based on these formulae were found to be in good agreement with experimental values for particle energy losses of light ions up to 70% of the nominal projectile energy value. ((orig.))

  14. Feather loss in laying hens

    Directory of Open Access Journals (Sweden)

    Hristov Slavča

    2006-01-01

    Full Text Available The paper examined the incidence of different forms of feather loss and cannibalism in laying hens aged 74 weeks following moulting and in laying hens following exploitation for a period of one year. The forms of feather loss were considered in detail through a repeated examination of video recordings and they were sorted according to localization - to feather loss on the ventral part of the neck, on the dorsal part of the neck, and on the back between the wings. Feather loss on the ventral part of the neck was established in 47.9% hens, and in the dorsal part in 16.77% hens of the 167 laying hens aged 74 weeks following moulting. The group of 129 laying hens that were observed following one-year exploitation exhibited considerably more frequent feather loss, in 96.90% hens it was localized on the ventral part of the neck, in 60.47% hens on the dorsal part of the neck, and in 20.16% hens it was localized on the back between the wings. A comparison of the results of the incidence of co localized forms of feather loss in the one and the other group of laying hens using the t-test showed statistically very significant differences. A detailed consideration of the video recordings using the method of sequence analysis did not reveal any cannibalism in either group of laying hens.

  15. Parametric study on coupling loss in subsize ITER Nb3Sn cabled specimen

    OpenAIRE

    Nijhuis, Arend; Kate, ten, F.J.W.; Bruzzone, Pierluigi; Bottura, Luca

    1996-01-01

    The cable in conduit conductors for the various ITER coils are required to function under pulse conditions and fields up to 13 T. A parametric study, restricted to a limited variation of the reference cable lay out, is carried out to clarify the quantitative impact of various cable parameters on the coupling loss and to find realistic values for the coupling loss time constants to be used in ac loss computations. The investigations cover ac coupling loss measurements on jacketed sub- and full...

  16. Investigation into loss in ferrofluid magnetization

    Directory of Open Access Journals (Sweden)

    J. Li

    2014-07-01

    Full Text Available Ferrofluids containing γ-Fe2O3/Ni2O3 nanoparticles (not chemically treated were synthesized using water and mixed water–glycerol as carrier liquid and the ferrofluid viscosity was modified by varying the glycerol content in the carrier liquid. The apparent magnetization of the ferrofluids decreased with increasing glycerol content. The loss in magnetization is described by the ratio of effective magnetic volume fraction to physical volume fraction of nanoparticles in the ferrofluids as a characteristic parameter. We ascribe the loss to the formation of “dead aggregates” having a ring-like structure of closed magnetic flux rather than to any chemical reaction. Such dead aggregates exist in zero magnetic field and do not contribute to the magnetization in the low or high field regime, so that the effective magnetic volume fraction in the ferrofluids decrease. An increase in carrier liquid viscosity is similar to a weakening of the thermal effect, so the number of dead aggregates increases and the magnetization decreases in inverse proportion to the viscosity. This relationship between the apparent magnetization and ferrofluid carrier liquid viscosity can be termed the “viscomagnetic effect”.

  17. Basic principles of ultrafast Raman loss spectroscopy

    Indian Academy of Sciences (India)

    N K Rai; A Y Lakshmanna; V V Namboodiri; S Umapathy

    2012-01-01

    When a light beam passes through any medium, the effects of interaction of light with the material depend on the field intensity. At low light intensities the response of materials remain linear to the amplitude of the applied electromagnetic field. But for sufficiently high intensities, the optical properties of materials are no longer linear to the amplitude of applied electromagnetic field. In such cases, the interaction of light waves with matter can result in the generation of new frequencies due to nonlinear processes such as higher harmonic generation and mixing of incident fields. One such nonlinear process, namely, the third order nonlinear spectroscopy has become a popular tool to study molecular structure. Thus, the spectroscopy based on the third order optical nonlinearity called stimulated Raman spectroscopy (SRS) is a tool to extract the structural and dynamical information about a molecular system. Ultrafast Raman loss spectroscopy (URLS) is analogous to SRS but is more sensitive than SRS. In this paper, we present the theoretical basis of SRS (URLS) techniques which have been developed in our laboratory.

  18. Economic inequality predicts biodiversity loss.

    Science.gov (United States)

    Mikkelson, Gregory M; Gonzalez, Andrew; Peterson, Garry D

    2007-05-16

    Human activity is causing high rates of biodiversity loss. Yet, surprisingly little is known about the extent to which socioeconomic factors exacerbate or ameliorate our impacts on biological diversity. One such factor, economic inequality, has been shown to affect public health, and has been linked to environmental problems in general. We tested how strongly economic inequality is related to biodiversity loss in particular. We found that among countries, and among US states, the number of species that are threatened or declining increases substantially with the Gini ratio of income inequality. At both levels of analysis, the connection between income inequality and biodiversity loss persists after controlling for biophysical conditions, human population size, and per capita GDP or income. Future research should explore potential mechanisms behind this equality-biodiversity relationship. Our results suggest that economic reforms would go hand in hand with, if not serving as a prerequisite for, effective conservation.

  19. Hearing loss at work? Hearing loss from leisure activities?

    CERN Multimedia

    2006-01-01

    The nurses of the Medical Service would like invite all persons working on the CERN site to take part in a: HEARING LOSS DETECTION WEEK From 28 August to 1st September 2006 At the Infirmary, Building 57 from 9 a.m. to 4 p.m. Hearing tests - advice - information - documentation - protective equipment

  20. Utilization of Sloping Field Resources and Confusion of Soil and Water Loss in China---Series Research Analysis on Soil and Water Resources%我国坡耕地资源开发利用与水土流失之困--水土资源系列调研分析

    Institute of Scientific and Technical Information of China (English)

    陶建格

    2014-01-01

    Soil and water are essential natural resources to the survival of humans.China is one of the most serious soil erosion countries in the world.Soil erosion is also currently a key solution to solve one of the major environmental prob-lems in China.The problems such as cultivated land resource shortage,limited per capita cultivated land,become the prominent contradiction between human and land.Utilization of sloping field resources becomes inevitable,but traditional extensive utilization of sloping field resources has lead to very serious soil and water losses.Reasonable utilization of slop-ing field resources has become one of the highlights of the current soil and water conservation work.In the process of a-nalysis on the investigation of soil and water resources in China,this paper analyses the importance of sloping field re-sources management for soil and water conservation work,the present situation in China,the causes of soil erosion and land,solves the problem of sloping field resources development and utilization of facing the confusion,and puts forward some measures and suggestions.%土壤和水分是人类赖以生存的基本自然资源条件。由于不合理的环境资源开发利用和气候、地理条件原因,水土流失成为当前期待解决的主要的环境问题之一,加强水土保持工作是我国环境保护的重要内容。客观的水土资源赋予造成我国耕地资源不足,人均少、东多西少等人地矛盾突出,坡耕地资源开发利用与农业成为必然,但传统粗放的坡耕地耕作已经形成十分严重的水土流失问题,合理开发利用坡耕地资源已经成为当前水土保持工作的重点之一。在对我国水土资源调研分析过程中,分析坡耕地治理对于水土保持工作的重要性、我国坡耕地的现状以及耕地造成水土流失的原因和解决坡耕地资源开发利用问题面临的困惑,提出解决坡耕地问题的一些措施和建议。

  1. Fast particle loss channels in Wendelstein 7-X

    Science.gov (United States)

    Faustin, J. M.; Cooper, W. A.; Graves, J. P.; Pfefferlé, D.; Geiger, J.

    2016-09-01

    One of the main goals of Wendelstein 7-X (W7-X) is to demonstrate the fast particle confinement properties of the quasi-isodynamic stellarator concept. Fast particle populations will be produced either by Neutral Beam Injection (NBI) or by minority Ion Cyclotron Resonant Heating (ICRH). A fraction of these particles are expected to be lost (even without collisions), despite the optimisation procedure used for the W7-X design. Confinement properties of NBI particles in W7-X were presented in the paper of Drevlak et al (2014 Nucl. Fusion 54 073002). A detailed study is presented here where the loss patterns of an NBI population are described. In particular, focussing on a high-mirror equilibrium, the confinement of fast ions with varying energy injection is studied under collisional conditions. It is found that collisions are not only responsible for classical transport losses but also enhance drift induced losses caused by trapped particles. Moreover, an asymmetry is found in the toroidal position of particle losses which can be explained by local variation in the equilibrium field. The effects of a neoclassically resolved radial electric field are also investigated. Fast particle confinement is significantly improved by the associated \\boldsymbol{E}× \\boldsymbol{B} drift. In particular, an increasing radial electric field helps to reduce and even stop the losses due to the 3D equilibrium structure for times comparable to slowing down time.

  2. The cost of job loss

    OpenAIRE

    Burdett, Ken; Carrillo-Tudela, Carlos; Coles, Melvyn

    2015-01-01

    In this paper we develop and quantitatively assess a tractable equilibrium search model of the labour market to analyse the long-term wage costs of a job loss. In our framework, these costs occur due to losses in workers' human capital and firm specific compensation, interruptions to workers' on-the-job search and due to turnover heterogeneity. A key feature is that firms post wage-tenure contracts as an optimal response to their employees' search behaviour and human capital accumulation. We ...

  3. Mass loss and stellar superwinds

    CERN Document Server

    Vink, Jorick S

    2016-01-01

    Mass loss bridges the gap between massive stars and supernovae (SNe) in two major ways: (i) theoretically it is the amount of mass lost that determines the mass of the star prior to explosion, and (ii) observations of the circumstellar material around SNe may teach us the type of progenitor that made the SN. Here, I present the latest models and observations of mass loss from massive stars, both for canonical massive O stars, as well as very massive stars (VMS) that show Wolf-Rayet type features.

  4. Visual loss after spine surgery

    Directory of Open Access Journals (Sweden)

    Kapil Mohan

    2012-01-01

    Full Text Available Incidence of perioperative visual loss ranges from 0.06% to 0.2% with the most common cause as ischemic optic neuropathy. We report one-year follow up of a 50-years-old hypertensive housewife who underwent lumbar decompression and fusion for degenerative scoliosis, but woke up with painless unilateral visual loss. Fundus examination was normal. Her visual acuity improved from initial finger counting close to face to finger counting at 3 m at 1 year. Identification of high risk patients may help in appropriate preoperative counselling, prevention and early recognition of this devastating complication.

  5. Supporting your child with weight loss

    Science.gov (United States)

    ... health care provider can set healthy goals for weight-loss and help with monitoring and support. Getting support ... to get the whole family to join a weight-loss plan, even if weight loss is not the ...

  6. ESTIMATING LOSS SEVERITY DISTRIBUTION: CONVOLUTION APPROACH

    Directory of Open Access Journals (Sweden)

    Ro J. Pak

    2014-01-01

    Full Text Available Financial loss can be classified into two types such as expected loss and unexpected loss. A current definition seeks to separate two losses from a total loss. In this article, however, we redefine a total loss as the sum of expected and unexpended losses; then the distribution of loss can be considered as the convolution of the distributions of both expected and unexpended losses. We propose to use a convolution of normal and exponential distribution for modelling a loss distribution. Subsequently, we compare its performance with other commonly used loss distributions. The examples of property insurance claim data are analyzed to show the applicability of this normal-exponential convolution model. Overall, we claim that the proposed model provides further useful information with regard to losses compared to existing models. We are able to provide new statistical quantities which are very critical and useful.

  7. Weight-Loss and Nutrition Myths

    Science.gov (United States)

    ... Alternate Language URL Español Weight-loss and Nutrition Myths Page Content Weight-loss and Diet Myths Meal ... and keep it off. Weight-loss and Diet Myths Myth: Fad diets will help me lose weight ...

  8. Body Contouring After Major Weight Loss

    Science.gov (United States)

    ... Blog Plastic Surgery Statistics ASPS TV News Program History of Plastic Surgery For Medical Professionals ... Major Weight Loss Body Contouring After Major Weight Loss For Men and Women Body contouring following major weight loss improves the ...

  9. Collisional trap losses of cold, magnetically-trapped Br atoms

    CERN Document Server

    Lam, J; Softley, T P

    2014-01-01

    Near-threshold photodissociation of Br$_2$ from a supersonic beam produces slow bromine atoms that are trapped in the magnetic field minimum formed between two opposing permanent magnets. Here, we quantify the dominant trap loss rate due to collisions with two sources of residual gas: the background limited by the vacuum chamber base pressure, and the carrier gas during the supersonic gas pulse. The loss rate due to collisions with residual Ar in the background follows pseudo first-order kinetics, and the bimolecular rate coefficient for collisional loss from the trap is determined by measurement of this rate as a function of the background Ar pressure. This rate coefficient is smaller than the total elastic collision rate coefficient, as it only samples those collisions that lead to trap loss, and is determined to be $\\langle\

  10. Experimental investigation of a.c. losses in cabled superconductors

    International Nuclear Information System (INIS)

    A.c. losses in multifilamentary composite superconducting strands and cables have been measured in adiabatic conditions for transverse field sweep rates up to 50 T s-1. Measurements were performed on NbTi and Nb3Sn conductors of several configurations and surface preparations: single strands, soldered strands and cables of varying degrees of compaction composed of bare strands, with CuNi barriers and strands with chrome plating. The experimental data agree well with existing loss models. The data suggests that the total cable loss grows as approx.= 1/(void)3 below void fractions of 40%. This observed cable loss dependence on void fraction does not agree well with a previously proposed model. (author)

  11. Positron energy-loss measurements in thin alumina films

    International Nuclear Information System (INIS)

    Transmitted-positron energy loss measurements were performed on approximately 100A alumina films with incident positron energies ranging from 0.5 to 3.0 keV. The positrons were electrostatically focussed on the film and the transmitted positrons were energy analyzed using a four-grid retarding field analyzer coupled with a two-stage channel electron multiplier plate connected with a phosphor screen. A strong transmitted elastic peak as well as indications of discrete energy losses were detected in these measurements. The observed discrete loss effects occurred at an average energy of approx. 25 eV and possibly approx. 50 eV. These findings are consistent with reported electron loss peaks due to plasmon excitation in alumina films

  12. Beam loss studies for the KEK compact-ERL

    International Nuclear Information System (INIS)

    We performed the beam loss study for the compact Energy Recovery Linac (cERL) at KEK. To this purpose the Touschek effect with intra-beam scattering, the residual gas scattering (elastic and inelastic cases) were examined using existing and modified ELEGANT routines, and developed MATLAB data analysis algorithms to handle the large amount of data that is produced by the program. In addition we performed several simulations to judge the impact of field emission issued from the main cavity. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beam line, which is important for the safety low-emittance and high-current beams operation. The data obtained then are compared with the theoretical estimation to verify the accuracy of the simulations. (author)

  13. Aromatic Polyurea Possessing High Electrical Energy Density and Low Loss

    Science.gov (United States)

    Thakur, Yash; Lin, Minren; Wu, Shan; Zhang, Q. M.

    2016-10-01

    We report the development of a dielectric polymer, poly (ether methyl ether urea) (PEMEU), which possesses a dielectric constant of 4 and is thermally stable up to 150°C. The experimental results show that the ether units are effective in softening the rigid polymer and making it thermally processable, while the high dipole moment of urea units and glass structure of the polymer leads to a low dielectric loss and low conduction loss. As a result, PEMEU high quality thin films can be fabricated which exhibit exceptionally high breakdown field of >1.5 GV/m, and a low conduction loss at fields up to the breakdown. Consequently, the PEMEU films exhibit a high charge-discharge efficiency of 90% and a high discharged energy density of 36 J/cm3.

  14. Does Job Loss Shorten Life?

    Science.gov (United States)

    Eliason, Marcus; Storrie, Donald

    2009-01-01

    This paper examines the impact of job loss on overall and cause-specific mortality. Using linked employer-employee data, we identified the workers displaced due to all establishment closures in Sweden in 1987 and 1988. Hence, we have extended the case study approach, which has dominated the plant closure literature. The overall mortality risk…

  15. FTO genotype and weight loss

    DEFF Research Database (Denmark)

    Livingstone, Katherine M; Celis-Morales, Carlos; Papandonatos, George D;

    2016-01-01

    OBJECTIVE: To assess the effect of the FTO genotype on weight loss after dietary, physical activity, or drug based interventions in randomised controlled trials. DESIGN: Systematic review and random effects meta-analysis of individual participant data from randomised controlled trials. DATA SOURC...

  16. Intellectual Disabilities and Hearing Loss

    Science.gov (United States)

    Herer, Gilbert R.

    2012-01-01

    Undetected/untreated hearing loss imposes significant limitations upon individuals with intellectual disabilities (ID). It can interfere with cognitive development, impede communicative and social interactions, and limit vocational aspirations. Over the past decade, the hearing of 9961 people with ID was evaluated at Special Olympics sports…

  17. 'Popper'-induced vision loss.

    Science.gov (United States)

    Krilis, Matthew; Thompson, Julia; Atik, Alp; Lusthaus, Jed; Jankelowitz, Stacey

    2013-05-01

    Amyl nitrite 'poppers' are recreational drugs, which are a potent source of nitric oxide. The use of 'poppers' can cause psychoactive stimulation, reduced blood pressure, tachycardia and involuntary muscle relaxation. Their use is becoming increasingly common around the world, including approximately 60% of Australia's male homosexual community. We report the first case of 'popper'-induced vision loss in Australasia.

  18. Older Adults and Smell Loss

    Medline Plus

    Full Text Available ... to accidents involving cooking, eating or drinking spoiled foods, or failing to detect gas leaks or fires. If you have a smell loss, there are things you can do to ensure your safety. Dr. Cowart: You need to be sure, as ...

  19. Older Adults and Smell Loss

    Medline Plus

    Full Text Available ... that you have functioning smoke detectors in your home. It's also possible to purchase home gas detectors and I would recommend that to ... a smell loss and uses gas in their home. Narrator: Smell and taste are closely linked in ...

  20. Older Adults and Smell Loss

    Medline Plus

    Full Text Available ... of smell. Maryann: The type of smell problem I have is, I can't smell at all. I have no sense of smell. Narrator: A sinus ... led to her loss of smell. Maryann: When I realized I no longer had a sense of ...