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Sample records for altitudinal field loss

  1. 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.

  2. 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.

  3. 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.

  4. Large-field dielectric loss in relaxor ferroelectric PLZT

    International Nuclear Information System (INIS)

    Lead zirconate titanate ceramics are often used at unipolar drive field levels approaching or exceeding the coercive field, yet dielectric losses are characterized by a loss tangent measured at a significantly lower drive field. As the magnitude of the drive field is increased the energy dissipation can increase significantly over that predicted by the low-field loss tangent. This experimental study addresses the effects of temperature and bias stress on large-field dielectric loss in lanthanum-doped lead zirconate titanate, Pb0.92La0.08(Zr0.65Ti0.35)0.98O3 (PLZT 8/65/35). Large-field dielectric loss was experimentally determined by measuring the area within a unipolar electric displacement–electric field hysteresis loop. The results show the effects of saturation on the effective loss tangent. (paper)

  5. Velocity-space particle loss in field-reversed configurations

    International Nuclear Information System (INIS)

    From particle confinement criteria for field-reversed configurations it is found that only a portion of (H,P/sub theta/) space, or equivalently, of velocity space, provides confinement. A loss region in velocity space is found. The effects of this loss region in velocity space are investigated. The velocity-space particle loss, i.e., particle loss caused by the existence of a loss region in velocity space, because of collisions is calculated from the Fokker--Planck equation. The corresponding scaling law for particle confinement is obtained. In collisional equilibrium, a simple analytical expression is verified to be a good representation of the actual velocity distribution in the presence of the loss region in velocity space. It is shown that velocity-space particle loss in field-reversed configurations is an important mechanism for particle loss, as well as the occurrence and spin-up of plasma rotation

  6. Uncertainty analysis for a field-scale P loss model

    Science.gov (United States)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study we assessed the effect of model input error on predic...

  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. Visual field loss while wearing full-face respiratory protection.

    Science.gov (United States)

    Zelnick, S D; McKay, R T; Lockey, J E

    1994-04-01

    The loss of visual field was quantified for 21 test subjects while they wore three full-face respirators. Changes in visual field were quantified for each type of respirator using a modified Goldmann projection perimeter. The loss of visual field was determined by calculating the area under the curve while wearing a respirator to that while wearing no respirator. Distinct patterns of visual field loss were apparent for the different style respirators. Analysis of the patterns could lead to the design of full-face respirators with improved visual qualities, which could improve worker safety for certain occupations. This technique also could be of help when selecting models of respiratory protection when certain visual fields must be maintained. PMID:8209836

  9. 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.

  10. Altitudinal distribution limits of aquatic macroinvertebrates

    DEFF Research Database (Denmark)

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

    2015-01-01

    1. Temperature and oxygen are recognised as the main drivers of altitudinal limits of species distributions. However, the two factors are linked, and both decrease with altitude, why their effects are difficult to disentangle. 2. This was experimentally addressed using aquatic macroinvertebrates...

  11. 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...

  12. 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.)

  13. Plasma Heating and Losses in Toroidal Multipole Fields

    International Nuclear Information System (INIS)

    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 1013cm-3 in the toroidal quadrupole and 1012cm-3 in the small octupole. Plasma losses for n=5 x 109cm-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. 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 ...

  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. Magnetic field diffusion and flux loss within a spheromak

    International Nuclear Information System (INIS)

    This paper considers the magnetic confinement of a plasma within a prototype controlled fusion experiment, the spheromak. This device has a containment vessel that is topologically spherical, offering considerable engineering advantages compared with conventional toroidal systems. The authors' aim has been to evaluate possible designs for the flux conserver and gun magnetic field coils, taking account of flux penetration into the walls caused by finite resisitivity. The copper walls cannot remain perfect magnetic flux surfaces for the duration of the experiment, and we calculate the magnetic field penetration into the walls for a range of designs. This study is in response to recent results showing that wall conditions and flux loss are a vital element of the system's performance, with a substantial increase in global resistance arising if field becomes embedded in the walls creating a dead space that is not driven by the gun current. The authors develop a model bearing general application to magnetic field interaction with resistive walls in complex geometries, with particular reference to the UMIST spheromak experiment SPHEX

  19. 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

  20. 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

  1. 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.

  2. Parallel divergent adaptation along replicated altitudinal gradients in Alpine trout

    Directory of Open Access Journals (Sweden)

    Keller Irene

    2012-10-01

    Full Text Available Abstract Background The European trout (Salmo trutta species complex occurs across a very wide altitudinal range from lowland rivers to alpine streams. Historically, the major European river systems contained different, evolutionarily distinct trout lineages, and some of this genetic diversity has persisted in spite of extensive human-mediated translocations. We used AFLP-based genome scans to investigate the extent of potentially adaptive divergence among major drainages and along altitudinal gradients replicated in several rivers. Results The proportion of loci showing evidence of divergent selection was larger between drainages than along altitudinal transects within drainages. This suggests divergent selection is stronger between drainages, or adaptive divergence is constrained by gene flow among populations within drainages, although the latter could not be confirmed at a more local scale. Still, altitudinal divergence occurred and, at approximately 2% of the markers, parallel changes of the AFLP band frequencies with altitude were observed suggesting that altitude may well be an important source of divergent selection within rivers. Conclusions Our results indicate that adaptive genetic divergence is common both between major European river systems and along altitudinal gradients within drainages. Alpine trout appear to be a promising model system to investigate the relative roles of divergent selection and gene flow in promoting or preventing adaptation to climate gradients.

  3. 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

  4. Effects of nonclassical ion losses on radial electric field in CHS torsatron/heliotron

    International Nuclear Information System (INIS)

    A selfconsistent analysis is discussed to determine the radial electric field and loss cone boundary in torsatron/heliotron plasmas under the influence of nonclassical ion losses. Effects of the loss cone loss, charge exchange loss of fast ions with neutrals, and the bipolar part of anomalous loss are taken into account. Analysis is applied to the NBI heated plasma in the CHS device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss , charge exchange loss and bulk heating is estimated by using the self-consistent electric field profile. The power loss of fast ions caused by the orbit loss or charge exchange process is by a factor of several tens to hundred greater than the reduction of the energy loss of bulk ions through the enhancement of radial electric field. Comparison with W7-A experiment is made, and the differences are discussed. (author)

  5. 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 =...

  6. Convective Power Loss Measurements in a Field Reversed Configuration with Rotating Magnetic Field Current Drive

    Science.gov (United States)

    Melnik, Paul

    The Translation, Confinement, and Sustainment Upgrade (TCSU) experiment achieves direct formation and sustainment of a field reversed configuration (FRC) plasma through rotating magnetic fields (RMF). The pre-ionized gas necessary for FRC formation is supplied by a magnetized cascade arc source that has been developed for TCSU. To ensure ideal FRC performance, the condition of the vacuum chamber prior to RMF start-up has been characterized with the use of a fast response ion gauge. A circuit capable of gating the puff valves with initial high voltage for quick response and then indefinite operational voltage was also designed. A fully translatable combination Langmuir / Mach probe was also built to measure the electron temperature, electron density, and ion velocity of the FRC. These measurements were also successfully completed in the FRC exhaust jets allowing for an accurate analysis of the FRC power loss through convection.

  7. 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

  8. 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

  9. 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

  10. 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...

  11. 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...

  12. 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.

  13. 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.

  14. Dissipative systems: radiation loss in the quantized field

    International Nuclear Information System (INIS)

    A simple model of a cavity coupled to the outside world and the use of appropriate boundary conditions provide the inclusion of dissipation in the quantized radiation field, in a non-artificial way. By defining collective operators which enable us to project the field into the internal optical cavity the exponential decay is obtained for the field inside the cavity. The initial conditions that lead to the exponential damping and the lower and upper bounds to this exponential evolution are also investigated. (Author)

  15. Improved models of β-limit, anomalous transport and radial electric field with loss cone loss in Heliotron/torsatron

    International Nuclear Information System (INIS)

    Theoretical study is made on the physics mechanisms which determine the beta-limit, the anomalous transport, and the radial electric field and loss cone. New theory is developed to analyze the stability boundary against the interchange mode in high-aspect-ratio toroidal helical plasmas, taking into account the transport processes. The stability β-limit is given at finite β-value, and the dependences on the plasma parameters and on the transport coefficient are investigated. It is found that the current-diffusive interchange mode is more important than the resistive mode in hot plasmas. The β-limit is predicted in the range of experimental observation for the anomalous transport. The dynamics of the pressure gradient and mode amplitude around this stability boundary are analysed. As the heating power is increased, the dynamics changes from the monotonous saturation, through the saturation with overshoot, and to the sawtoothing. Using the mean-field theory approach of statistical physics for the microscopic current-diffusive interchange mode, the anomalous transport theory is developed. The expression of the thermal transport coefficient is obtained. The pressure gradient, not the temperature itself, enhances the transport coefficient. Comparison with experimental observations from various aspects is made, and the model explains experimental observations. The method to obtain the self-consistent picture of the radial electric field Er and the loss cone loss is explored. The structure of Er and the loss cone are obtained, and it is confirmed that the direct ion loss makes Er near edge more negative. Effects of other nonclassical loss are also evaluated. (author)

  16. 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.

  17. 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.

  18. 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

  19. 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.

  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. Calorimetric method of ac loss measurement in a rotating magnetic field

    International Nuclear Information System (INIS)

    A method is described for calorimetric ac-loss measurements of high-Tc superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  2. Calorimetric method of ac loss measurement in a rotating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, P. K. [Oxford Instruments NanoScience, Abingdon, Oxfordshire OX13 5QX (United Kingdom); Coombs, T. A.; Campbell, A. M. [Department of Engineering, Electrical Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2010-07-15

    A method is described for calorimetric ac-loss measurements of high-T{sub c} superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  3. Calorimetric method of ac loss measurement in a rotating magnetic field

    Science.gov (United States)

    Ghoshal, P. K.; Coombs, T. A.; Campbell, A. M.

    2010-07-01

    A method is described for calorimetric ac-loss measurements of high-Tc superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  4. Eddy current losses in multiwire superconductors duel to external perpendicular magnetic field

    International Nuclear Information System (INIS)

    Approximate method is presented of calculation of eddy current losses in a multiwire superconductor from an ac magnetic field perpendicular to the conductor axis, based on the solution of the equivalent magnetic circuit. The results of the solution show that the loss power output of the eddy currents from this field is neglibible inside the wire zone. A relatively greater loss power output appears in the stabilizing sheath of the conductor if it has greater thickness. The thickness of the stabilizing sheath influences the loss power outut proportionally to the third and fourth powers. (authors). 5 figs., 2 tabs., 5 refs

  5. Reconstruction of material losses by perimeter penalization and phase-field methods

    OpenAIRE

    Rondi, Luca

    2009-01-01

    We treat the inverse problem of determining material losses, such as cavities, in a conducting body, by performing electrostatic measurements at the boundary. We develop a numerical approach, based on variational methods, to reconstruct the unknown material loss by a single boundary measurement of current and voltage type. The method is based on the use of phase-field functions to model the material losses and on a perimeter-like penalization to regularize the otherwise ill-posed problem.We j...

  6. 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

  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. Some Considerations on Tunneling Losses in Field-Effect Devices for Low-Voltage Microcontrollers

    OpenAIRE

    M. Grado-Caffaro; M. A. Grado-Caffaro

    1998-01-01

    The loss power density associated with the tunneling current in a typical MOS cell with a floating gate is evaluated for high electric-field strengths in the oxide layer. Furthermore, problems related to oxide thickness are discussed.

  9. The Effects of Ageing and Visual Field Loss on Pointing to Visual Targets

    OpenAIRE

    Rubinstein, Nikki J.; Anderson, Andrew J.; Ma-Wyatt, Anna; Walland, Mark J.; McKendrick, Allison M.

    2014-01-01

    Purpose To investigate the effect of ageing on visuomotor function and subsequently evaluate the effect of visual field loss on such function in older adults. Methods Two experiments were performed: 1) to determine the effect of ageing on visual localisation and subsequent pointing precision, and 2) to determine the effect of visual field loss on these outcome measures. For Experiment 1, we measured visual localisation and pointing precision radially at visual eccentricities of 5, 10 and 15° ...

  10. Leaf gas exchange in Espeletia schultzii Wedd, a giant caulescent rosette species, along an altitudinal gradient in the Venezuelan Andes

    Science.gov (United States)

    Rada, Fermin; Azocar, Aura; Gonzalez, Juan; Briceño, Benito

    1998-02-01

    Gas exchange studies along low altitudinal gradients (0-2 500 metres above sea level) suggest an increase in plant CO 2 assimilation with increasing altitude. The question arises however, will this hold true for higher altitudinal ranges? The purpose of this work was to characterize carbon and water relationships in Espeletia schultzii along an extreme altitudinal gradient. Gas exchange characteristics under field conditions during wet and dry seasons were documented for Espeletia schultzii, a giant caulescent rosette species, along an altitudinal gradient (2 950, 3 550 and 4 200 m) in the Venezuelan Andes. Significant differences in CO 2 assimilation rates between seasons were found for all studied sites. Low assimilation rates obtained during the dry season were a consequence of: low leaf conductances to counteract low leaf water potentials and/or high vapour pressure differences between leaf and air, and to high leaf temperatures measured during the dry season. Important differences in A/P i curve parameters were obtained between wet and dry seasons. A decrease in A max was observed for the two lower populations, while a similar value was obtained for both wet and dry seasons at the higher altitude. A decrease in the relation P i/P a and an increase in stomatal limitation and leaf temperature were measured from wet to dry season. There was a differentiation in CO 2 assimilation with increasing altitude. At 2 950 m, maximum rates were above 5 μmol · m -2 · s -1, at 3 550 m 3 μmol · m -2 · s -1, while at 4 200 m maximum CO 2 assimilation rate was below 3 μmol ·m -2 · s -1. This decrease may be explained by: an increase in leaf pubescence, lower leaf conductances and/or lower leaf nitrogen content at higher altitude.

  11. Does soil acidity explain altitudinal sequences in collembolan communities?

    OpenAIRE

    Loranger, Gladys; Bandyopadhyaya, Ipsa; Razaka, Barbara; Ponge, Jean-François

    2001-01-01

    Altitudinal changes in collembolan communities were studied by sampling soil microarthropods along a gradient from 950 to 2150 m a.s.l., under a wide range of forest vegetation types. A multivariate method showed that most changes in species composition followed changes in soil chemistry, humus forms and vegetation. A transition from mull to mor humus, with concomitant soil acidification, was observed with increasing elevation. It was observed that at a given elevation, changes in soil acidit...

  12. 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

  13. 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.

  14. 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

  15. Improved image quality of a Ag slab near-field superlens with intrinsic loss of absorption.

    Science.gov (United States)

    Lee, Kwangchil; Park, Haesung; Kim, Jaehoon; Kang, Gumin; Kim, Kyoungsik

    2008-02-01

    Intrinsic loss of absorption in the Ag slab near-field superlens turned out to add a blurring effect to the ideal image reconstruction for the impedance match case. By optimizing the real part of the permittivity (epsilon') of Ag, our FDTD calculation predicts approximately 69% enhancement of visibility and approximately 138% increased depth of field for the intensity contrast of 0.5 with similar focal spot size. For a near-field superlens with the higher absorption loss, the optimized image quality is obtained with a larger impedance mismatch, which can be realized by changing the wavelength of incident light for imaging. PMID:18542250

  16. Effects of peripheral visual field loss on eye movements during visual search

    Directory of Open Access Journals (Sweden)

    EmilyWiecek

    2012-11-01

    Full Text Available Natural vision involves sequential eye movements that bring the fovea to locations selected by peripheral vision. How peripheral visual field loss (PVFL affects this process is not well understood. We examine how the location and extent of PVFL affects eye movement behavior in a naturalistic visual search task. Ten patients with PVFL and thirteen normally sighted subjects with full visual fields (FVF completed 30 visual searches monocularly. Subjects located a 4 x 4 degree target, pseudo-randomly selected within a 26 x 11 degree natural image. Eye positions were recorded at 50 Hz. Search duration, fixation duration, saccade size, and number of saccades per trial were not significantly different between PVFL and FVF groups (p > 0.1. A Chi-square test showed that the distributions of saccade directions for PVFL and FVL subjects were significantly different in 8 out of 10 cases (p < .01. Humphrey Visual Field pattern deviations for each subject were compared with the spatial distribution of eye movement directions. There were no significant correlations between saccade directional bias and visual field sensitivity across the 10 patients. Visual search performance was not significantly affected by peripheral visual field loss. An analysis of eye movement directions revealed patients with PVFL show a biased directional distribution that was not directly related to the locus of vision loss, challenging feed-forward models of eye movement control. Consequently, many patients do not optimally compensate for visual field loss during visual search.

  17. 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.

  18. Improvement of terahertz field effect transistor detectors by substrate thinning and radiation losses reduction.

    Science.gov (United States)

    Coquillat, Dominique; Marczewski, Jacek; Kopyt, Pawel; Dyakonova, Nina; Giffard, Benoit; Knap, Wojciech

    2016-01-11

    Phenomena of the radiation coupling to the field effect transistors based terahertz (THz) detectors are studied. We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, is coupled to an antenna substrate leading to responsivity losses and/or cross-talk effects in the field effect based THz detector arrays. Experimental and theoretical investigations of the responsivity versus substrate thickness are performed. They clearly show how to minimize the losses by the detector/ array substrate thinning. In conclusion simple quantitative rules of losses minimization by choosing a proper substrate thickness of field effect transistor THz detectors are presented for common materials (Si, GaAs, InP, GaN) used in semiconductor technologies. PMID:26832258

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

    International Nuclear Information System (INIS)

    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

  20. Investigation of magnetic fluids exhibiting field-induced increasing loss peaks

    Science.gov (United States)

    Fannin, P. C.; Marin, C. N.; Couper, C.

    2010-05-01

    A theoretical analysis to explain an increase of the Brownian loss peak with increasing polarizing field, H, in a magnetic fluid, is presented. The model is based on the competition between the Brownian and Néel relaxation processes. It is demonstrated that in magnetic fluids with particles having small anisotropy constant, small average magnetic diameter and narrow particle size distribution an increase of the Brownian loss peak with the polarizing field can be observed. The theoretical results are compared with the experimental results of an Isopar M-based magnetic fluid with magnetite particles stabilized with oleic acid and the model explains qualitatively the main characteristics of the experimental results.

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

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. 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.

  5. Sensitivity and uncertainty analysis for a field-scale P loss model

    Science.gov (United States)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that there are inherent uncertainties with model predictions, limited studies have addressed model prediction uncertainty. In this study we assess the effect of model input error on predict...

  6. 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)

  7. 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 ...

  8. 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

  9. 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

  10. Quantification of visual field loss in age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Jennifer H Acton

    Full Text Available BACKGROUND: An evaluation of standard automated perimetry (SAP and short wavelength automated perimetry (SWAP for the central 10-2 visual field test procedure in patients with age-related macular degeneration (AMD is presented in order to determine methods of quantifying the central sensitivity loss in patients at various stages of AMD. METHODS: 10-2 SAP and SWAP Humphrey visual fields and stereoscopic fundus photographs were collected in 27 eyes of 27 patients with AMD and 22 eyes of 22 normal subjects. RESULTS: Mean Deviation and Pattern Standard Deviation (PSD varied significantly with stage of disease in SAP (both p<0.001 and SWAP (both p<0.001, but post hoc analysis revealed overlap of functional values among stages. In SWAP, indices of focal loss were more sensitive to detecting differences in AMD from normal. SWAP defects were greater in depth and area than those in SAP. Central sensitivity (within 1° changed by -3.9 and -4.9 dB per stage in SAP and SWAP, respectively. Based on defect maps, an AMD Severity Index was derived. CONCLUSIONS: Global indices of focal loss were more sensitive to detecting early stage AMD from normal. The SWAP sensitivity decline with advancing stage of AMD was greater than in SAP. A new AMD Severity Index quantifies visual field defects on a continuous scale. Although not all patients are suitable for SWAP examinations, it is of value as a tool in research studies of visual loss in AMD.

  11. 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

    2016-04-01

    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.

  12. 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.

  13. Perfil altitudinal de la temperatura media del aire en Colombia

    Directory of Open Access Journals (Sweden)

    Eslava Jesus

    1992-10-01

    Full Text Available

    Se establecen ecuaciones que relacionan la temperatura media anual del aire en

    Colombia con la altitud. Por medio de ellas se posibilita estimar los valores de esa temperatura en cualquier lugar, con el requisito de conocer únicamente el dato de su altitud y ubicación regional; también se determinan los gradientes altitudinales que, a su vez, posibilitan conocer cualquier otro dato de temperatura del aire,  conociendo los datos de otro sitio o estación base. Las ecuaciones muestran que los valores a nivel del mar y la variación altitudinal de la temperatura del aire en Colombia no son únicos, sino que cambian según las condiciones físicas de cada región o subregión y se diferencias sustancialmente de los valores propuestos con anterioridad por otros autores.

    Equations that establish relations between annual average temperature and altitude are defined for Colombia. These equations allow to estimate temperature values at any place, just by knowing altitude and regional location data. It is also possible to determine altitudinal gradients, which in turn allows to know the temperature of a given place, from the data for a base. The defined equations show that temperature is not a unique function of altitudinal changes, but it also depends on specific physical conditions for each region or subregion.

  14. 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.

  15. 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...

  16. 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.

  17. 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.

  18. Possible control scenario of radial electric field by loss-cone-particle injection into helical device

    International Nuclear Information System (INIS)

    The possibility of controlling the radial electric field of toroidal plasmas by injecting high energy electrons along the reversible loss cone orbit of the helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scenario especially in the low collisional regime under the physics picture of neoclassical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically trapped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible for particles to penetrate deeply into the plasma. In addition we clarify that the viscosity of the plasma coupled with the helical field configuration provide a bifurcation of plasma states and its stable solution results in confinement improvement. (author)

  19. Modelling and computation of AC fields and losses in high temperature superconductors

    International Nuclear Information System (INIS)

    This thesis is concerned with the modelling and the computation of the AC losses and electromagnetic fields in high temperature superconducting tapes using an E - J characteristic diffusion model. The AC losses in high temperature superconductors are modelled as a highly non-linear diffusion process. An empirical expression for modelling effective resistivity of the tape is extracted from the Rhyner's model and then used in the build up of the diffusion model. Formulation in terms of electric field E is used extensively and comprehensive explanations of why this model is used are given. Using the E formulation three different models that describe three different cases of the problem are developed. To understand the physical and the numerical phenomena that occur when a superconducting tape carries an alternating current or is exposed to an external variable magnetic field a one-dimensional model has been developed first. Comprehensive details and results of the principle and formulation of the primary model are given. The solid basis created by the one-dimensional model and the necessity of the model to be closer to the real tape drive us to two more realistic models, one where a silver layer is added on the top of the superconducting core, and the second one is the two-dimensional model where the edge effects and importance of non-linearity is emphasised. For both of these models comprehensive formulations and results are given. A collection of programs that solves the models has been created and tested, and the results obtained where successfully compared with results obtained by other authors through numerical and experimental means. The research demonstrates that the models developed are useful in exploring the mechanism of AC losses in superconducting tapes, the numerical programs allow prediction of losses under particular conditions and the applicability of different models (one and two-dimensional, the ''sandwich model'' and the critical state model

  20. Altitudinal and seasonal differences of tick communities in dogs from pastoralist tribes of Northern Kenya

    Czech Academy of Sciences Publication Activity Database

    D'Amico, G.; Dumitrache, M.O.; Široký, P.; Albrechtová, K.; Sloboda, M.; Domsa, C.; Sándor, A.D.; Balázsi, R.; Kanyari, P. W. N.; Modrý, David; Mihalca, A. D.

    2015-01-01

    Roč. 212, 3-4 (2015), s. 318-323. ISSN 0304-4017 Institutional support: RVO:60077344 Keywords : Altitudinal distribution * Rhipicephalus sanguineus * Rhipicephalus pulchellus * Rhipicephalus armatus Subject RIV: CE - Biochemistry Impact factor: 2.460, year: 2014

  1. 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...

  2. 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....

  3. 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

  4. 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.

  5. Acoustic propagation through anisotropic internal wave fields: Transmission loss, cross-range coherence, and horizontal refraction

    Science.gov (United States)

    Oba, Roger; Finette, Steven

    2002-02-01

    Results of a computer simulation study are presented for acoustic propagation in a shallow water, anisotropic ocean environment. The water column is characterized by random volume fluctuations in the sound speed field that are induced by internal gravity waves, and this variability is superimposed on a dominant summer thermocline. Both the internal wave field and resulting sound speed perturbations are represented in three-dimensional (3D) space and evolve in time. The isopycnal displacements consist of two components: a spatially diffuse, horizontally isotropic component and a spatially localized contribution from an undular bore (i.e., a solitary wave packet or solibore) that exhibits horizontal (azimuthal) anisotropy. An acoustic field is propagated through this waveguide using a 3D parabolic equation code based on differential operators representing wide-angle coverage in elevation and narrow-angle coverage in azimuth. Transmission loss is evaluated both for fixed time snapshots of the environment and as a function of time over an ordered set of snapshots which represent the time-evolving sound speed distribution. Horizontal acoustic coherence, also known as transverse or cross-range coherence, is estimated for horizontally separated points in the direction normal to the source-receiver orientation. Both transmission loss and spatial coherence are computed at acoustic frequencies 200 and 400 Hz for ranges extending to 10 km, a cross-range of 1 km, and a water depth of 68 m. Azimuthal filtering of the propagated field occurs for this environment, with the strongest variations appearing when propagation is parallel to the solitary wave depressions of the thermocline. A large anisotropic degradation in horizontal coherence occurs under the same conditions. Horizontal refraction of the acoustic wave front is responsible for the degradation, as demonstrated by an energy gradient analysis of in-plane and out-of-plane energy transfer. The solitary wave packet is

  6. Influence of longitudinal components of magnetic field on the volume pinning force and the losses of NbTi superconductors

    International Nuclear Information System (INIS)

    Measurements of the critical current of NbTi superconductors have been performed in dependence of both the external magnetic field and the angle between the conductor axis and the magnetic field. For heavily cold worked samples a marked anisotropy of the volume pinning force has been found. While the theory of pinning forces of Dew-Hughes is based upon the assumption that interactions between flux lines can be neglected in hard superconductors, model calculations show that the observed anisotropy is due to the effectiveness of the elastic properties of the flux line lattice. The influence of this anisotropy on the hysteresis losses has been studied by magnetization measurements. - Measurements of the frequency dependence of the losses of twisted multifilamentary wires in parallel fields showed a new coupling effect between the superconducting filaments and a corresponding increase in losses. The calculation of these extra losses shows good agreement with the experimental results. An alternating twist is proposed to reduce these losses. (orig.)

  7. Experimental investigation of compact toroid formation, dynamics, and plasma loss in a field reversed theta pinch

    International Nuclear Information System (INIS)

    Results of an experimental investigation of compact toroid formation, dynamics, and plasma loss in a 50-cm-long field reversed theta pinch are presented. A combination of radio frequency incipient ionization coupled with fast ringing theta discharges was used to trap a uniform 0.92 kG magnetic bias field in a deuterium gas over a 20 to 200 mtorr fill pressure range in a 9-cm diameter discharge tube. A reversed 4.54 kJ crowbarred discharge with a rise time of 3.4 μs was used to form compact toroids exhibiting lifetimes up to 60 μs. A diamagnetic loop, magnetic loop, magnetic probes, pressure probes, spectroscopy, photodiodes, and photography were used as diagnostics to investigate preionization, bias field generation, and trapping, stable lifetime characteristics, and eventual compact toroid destruction. Separatrix radius electron temperature, and electron density as a function of time and pressure are calculated from experimental data. Symmetry and rotational stability are illustrated over the lifetime of the compact toroids. Results indicate that like the Russian experiments but unlike the results at Los Alamos, compact toroids formed in the Penn State machine were limited in life by the decay characteristics of the applied magnetic field and not by the n = 2 rotational instability

  8. Altitudinal distribution of soil fauna in the Khibiny Massif

    Science.gov (United States)

    Zenkova, I. V.; Pozharskaya, V. V.; Pokhil'Ko, A. A.

    2011-09-01

    Data on the taxonomic and trophic composition, population density, and biomass of invertebrates in the soils of the main mountain vegetation zones of the Khibiny Mountains—taiga, subalpine, and alpine—are obtained. The degree of similarity between soil faunal complexes in different vegetation zones within the studied slope is higher than that between zonal biocenoses of Murmansk oblast. The mountain tundra zone differs from the zonal tundra in a higher population density and taxonomic diversity of invertebrates, which are similar to those in the northern taiga podzols. At the same time, invertebrate complexes in the mountain taiga zone are poorer than those in the zonal plain taiga soils. The analysis of invertebrate taxa present in all the studied mountain vegetation zones demonstrates similar effects of the altitudinal and latitudinal zonality on the species composition of invertebrates. A conclusion is made about a higher functional activity of saprotrophs in the high-humus soils enriched in biogenic elements of the Khibiny Mountains in comparison with the functional activity of saprotrophs in the zonal plain podzols.

  9. Altitudinal zonation of runoff in the Rasina River Basin

    Directory of Open Access Journals (Sweden)

    Manojlović Predrag

    2013-01-01

    Full Text Available The Rasina River Basin is located on the territory of Central Serbia. The aim of this paper is to determine the amount and spatial distribution of water resources, that is, to establish the participation of altitudinal zones in the formation of the total runoff in the Rasina River Basin area upstream from the "Ćelije" reservoir. In terms of methodology, determination of water volume is based on four separated petrological-hydrological complexes. Average weighted specific runoff in a given territory is 9 l/s/km2. Metamorphites and magmatites are in the first place per participation in the total water runoff of 42.8 %. The second place belongs to sedimentary rocks that make 39.6 % of the total runoff . Unbound sediments participate in the total runoff value with 10.5 % and limestone with 7.1%. [Projekat Ministarstva nauke Republike Srbije, br. 43007: The Research on Climate Change Influences on Environment: Influence Monitoring, Adaptation and Mitigation

  10. Dynamics of radiation losses in Z-pinch plasma with taking into account generation of turbulent magnetic fields

    International Nuclear Information System (INIS)

    We estimated the total radiation losses from argon Z-pinches. Radiation losses due to excitation, di-electronic recombination, Bremsstrahlung, radiative recombination and also ionization, were considered. Each separate ion is analyzed in detail and the influence of density is taken into account. Our pinch dynamics includes Joule heating, anomalous plasma resistance, plasma outflow in Z-direction, electron beam generation, magnetic field pressure, radiation losses. Main novelty of the given model is generation of chaotic/turbulent magnetic fields. It is shown, that turbulent magnetic fields affect the dynamics of plasma parameters. The influence of turbulent magnetic field is analyzed on the dynamics of plasma temperature, density, radiation losses, line emission. (author)

  11. Hysteretic ac loss in a coated superconductor subjected to oscillating magnetic fields: ferromagnetic effect and frequency dependence

    International Nuclear Information System (INIS)

    Numerical simulations of the hysteretic ac loss in a coated superconductor with a more realistic version of the architecture were performed via the finite-element technique in the presence of an oscillating magnetic field. The coated superconductor was electromagnetically modeled by resorting to the quasistatic approximation of a vector potential approach in conjunction with nonlinear descriptions of the superconducting layer and the ferromagnetic substrate therein by a power-law model and the Langevin equation, respectively. A diverse effect of the ferromagnetic substrate on the hysteretic ac loss, depending on the strength of the applied magnetic field, was displayed, and its underlying cause was identified. The dependence of the hysteretic ac loss on the applied frequency is found to be related to a critical amplitude of the applied magnetic field, and the eddy-current loss dissipated in the metal coatings becomes prominent as the frequency increases only at high applied magnetic fields. (paper)

  12. Critical fields and anomalous loss mechanisms in superconducting cavity resonators made of niobium

    International Nuclear Information System (INIS)

    To increase the accelerating gradients and the quality factors of superconducting niobium cavities, this work aims at understanding and avoiding the limiting anomalous loss mechanisms. Special interest is applied to the non-resonant electron loading (field emission) and to the field dependent residual surface resistance. To study these effects, new types of high resolution X-ray- and temperature-mapping systems are developed. The experimental observations are interpreted on the basis of analytical approximations and numerical simulation calculations. In addition to the avoidance of anomalous losses, it is shown by model calculations and then confirmed experimentally that a high thermal conductivity of the cavity wall shifts the thermal breakdown of superconductivity at local surface defects to higher field strengths. To make use of this effect, solid state gettering techniques that lower the oxygen content of the niobium by evaporating a thin titanium layer onto the niobium surface at 1350 C are developed. In addition, this postpurification technique is shown to be necessary to prevent oxygen pickup from the residual gas of the vacuum furnace at temperatures above 1200 C. The experimental findings, obtained in test series on nineteen cavities with different chemical purity, are used to optimize the techniques to clean, handle, mount, and operate niobium cavities. This results in promising acceleration gradients of Eacc = 27, 22, 20, and 10 MV/m in the best 3-GHz-cavities with one, five, nine, and twenty cells, respectively. The quality factor at 1.4 K is always close to 1010. The advantages and disadvantages of the different surface preparation techniques are reported. (orig./MM)

  13. Toward an integrated view of ionospheric plasma instabilities: Altitudinal transitions and strong gradient case

    Science.gov (United States)

    Makarevich, Roman A.

    2016-04-01

    A general dispersion relation is derived that integrates the Farley-Buneman, gradient-drift, and current-convective plasma instabilities (FBI, GDI, and CCI) within the same formalism for an arbitrary altitude, wave propagation vector, and background density gradient. The limiting cases of the FBI/GDI in the E region for nearly field-aligned irregularities, GDI/CCI in the main F region at long wavelengths, and GDI at high altitudes are successfully recovered using analytic analysis. Numerical solutions are found for more general representative cases spanning the entire ionosphere. It is demonstrated that the results are consistent with those obtained using a general FBI/GDI/CCI theory developed previously at and near E region altitudes under most conditions. The most significant differences are obtained for strong gradients (scale lengths of 100 m) at high altitudes such as those that may occur during highly structured soft particle precipitation events. It is shown that the strong gradient case is dominated by inertial effects and, for some scales, surprisingly strong additional damping due to higher-order gradient terms. The growth rate behavior is examined with a particular focus on the range of wave propagations with positive growth (instability cone) and its transitions between altitudinal regions. It is shown that these transitions are largely controlled by the plasma density gradients even when FBI is operational.

  14. 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 ...

  15. On the influences of stochastic magnetic fields on transport coefficients, runaway losses, and heat flux patterns

    International Nuclear Information System (INIS)

    Edge stochastization is a candidate for the plasma-wall-interaction control. In the present presentation, three aspects of stochastic plasmas are demonstrated, namely transport coefficients, runaway losses, and heat flux patterns. First, for stochastic magnetic flux functions with percolative contours the existing test particle transport theories are reviewed. Using the de correlation trajectory method (DCT), the relation between the Lagrangian velocity correlation function and the Eulerian magnetic field correlation is discussed. Specific results are presented in the percolation regime corresponding to high Kubo numbers. For different percolative scenarios the diffusion is analyzed and strong influences of the percolative structures on the transport scaling are found. Numerical simulations of the A-Langevin equation confirm the semi-analytical predictions. Next, guiding-center motion is analyzed in relativistic invariant form for toroidal geometry. Including stochastic magnetic field components, a symmetric Hamiltonian mapping technique, leading to a 4-dimensional iteration procedure, is developed. The latter is analyzed in detail for increasing (relativistic) kinetic energies of the particles, i.e. runaway electrons. The dependency of the escape rates on the kinetic energy is calculated and compared to the escape rates for field lines. The non-relativistic limit of the model is derived. Quantitative results for the magnetic perturbations in a dynamic ergodic divertor (DED) of the TEXTOR experiment are shown, and predictions for runaway electrons are compared with experiments. Finally, we interpret heat flux patterns caused by stochastic magnetic fields. Experimental observations of heat fluxes on divertor plates of tokamaks show typical structures (boomerang wings) for varying edge safety factors. It is shown that the heat flux patterns follow from general principles of nonlinear dynamics. The pattern selection is due to the unstable and stable manifolds of the

  16. Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes

    International Nuclear Information System (INIS)

    The present study shows the occurrence of 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes. - Highlights: → BDE-209 is found in high mountain areas despite its low vapor pressure. → Aerosol air transport may transport BDE-209 to high mountain sites. → BDE-209 and PBDEs exhibit altitudinally-dependent distributions. → PBDE bacterial anaerobic debromination is important in mountain areas. → Biodegradation may generate altitudinal and latitudinal concentration gradients. - Decabromodiphenyl ether and the other polybromodiphenyl congeners show vertical distributions in high mountains due to temperature effects and microbial degradation.

  17. Altitudinal distributions of BDE-209 and other polybromodiphenyl ethers in high mountain lakes

    Energy Technology Data Exchange (ETDEWEB)

    Bartrons, Mireia [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona, 18, 08034 Barcelona, Catalonia (Spain); Limnology Unit (CSIC-UB), Centre for Advanced Studies of Blanes (CEAB-CSIC), Acces Cala St. Francesc, 14, 17300 Blanes, Catalonia (Spain); Grimalt, Joan O., E-mail: joan.grimalt@idaea.csic.es [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona, 18, 08034 Barcelona, Catalonia (Spain); Catalan, Jordi [Limnology Unit (CSIC-UB), Centre for Advanced Studies of Blanes (CEAB-CSIC), Acces Cala St. Francesc, 14, 17300 Blanes, Catalonia (Spain)

    2011-07-15

    The present study shows the occurrence of 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) in microbial biofilms of Pyrenean and Tatra high mountain lakes despite its low vapor pressure and high hydrophobicity. Aerosol air transport is therefore a feasible mechanism for BDE-209 accumulation in sites up to 2688 m above sea level. This compound and other PBDEs exhibit altitudinally-dependent distribution involving higher concentrations with increasing mountain lake elevation. However, the apparently very high enthalpies of the concentration gradients observed, including BDE-209, suggest that bacterial anaerobic debromination also plays a significant role in the resulting altitudinal distributions. This microbial mechanism explains the relative abundances of PBDEs and their within lake differences between rocky and sediment microbial biofilms, thereby showing that the altitudinal pattern observed is not purely due to water temperature control on bacterial activity but also to changes in the availability of anaerobic microenvironments which increase with increasing lake productivity at lower altitudes. - Highlights: > BDE-209 is found in high mountain areas despite its low vapor pressure. > Aerosol air transport may transport BDE-209 to high mountain sites. > BDE-209 and PBDEs exhibit altitudinally-dependent distributions. > PBDE bacterial anaerobic debromination is important in mountain areas. > Biodegradation may generate altitudinal and latitudinal concentration gradients. - Decabromodiphenyl ether and the other polybromodiphenyl congeners show vertical distributions in high mountains due to temperature effects and microbial degradation.

  18. Electron Cyclotron Power Losses in ITER for 2D Profile of Magnetic Field

    International Nuclear Information System (INIS)

    Full text: Recent comparison of numeric codes SNECTR, CYTRAN, CYNEQ and EXACTEC for calculating the 1D distribution, over magnetic flux surfaces, of the net electron cyclotron (EC) radiated power density, Pec(ρ), was carried out for a flat 1D profile of total magnetic field, which is an average over each magnetic surface and is used in 1.5D transport models: Btot(ρ) = BT (Ro) = Bo, vacuum toroidal magnetic field on toroid's axis. However, the predicted rise of Te in steady-state operation regimes in ITER and future reactors requires better accuracy of Pec(ρ) calculations, especially in the plasma hot core. Here we take into account the inhomogeneity of magnetic field in 2D approximation in the modified code CYNEQ. We compare three approximations of the magnetic field profile: (i) 2D-magnetic field B(R, Z); (ii) 1D - flux surface averaged magnetic field B(ρ)= (B(R, Z)); (iii) 0D - homogeneous magnetic field B = Bo. It is shown that, for the same plasma parameters expected in ITER, the Pec(ρ) profiles in the cases (i) and (ii) are very close, being lower than Pec(ρ) in the central plasma in the case of B = Bo = 5.3 T. In particular, for the enhanced confinement scenario, the decrease reaches ∼ 25%. The above effect has to be taken into account in the 1.5D transport codes when modeling the steady-state regimes of ITER operation. When central temperature increases to ∼ 30 keV the local EC power loss becomes a substantial part of heating from fusion alphas and exceeds the auxiliary heating from neutral beam. On the other hand, fast increase of Pec(0) with temperature has a positive impact on stabilization of fusion burning. Thus, for reactor scale parameters, accurate simulations of nonlocal heat transport by EC waves requires self-consistent 1.5D calculations of plasma parameters with 2D equilibrium. Meanwhile the EC energy transport has sufficient accuracy with 1D surface-averaged magnetic field B(ρ)= (B(R, Z)), derived from self-consistent 1.5D simulations

  19. 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.

  20. 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.

  1. 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.

  2. [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

  3. 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.

  4. AC loss of HTS magnet for AMR refrigerator using magnetic field formulation and edge element in cylindrical coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seo Ho; Park, Minwon [Changwon National University, Changwon (Korea, Republic of); Jeong, Sang Kwon [KAIST, Daejeon (Korea, Republic of)

    2013-05-15

    AMR (Active Magnetic Regenerative) refrigerators require the large variation of the magnetic field and a HTS magnet can be used. The amount of AC loss is very important considering the overall efficiency of the AMR refrigerator. However, it is very hard to estimate the precise loss of the HTS magnet because the magnetic field distribution around the conductor itself depends on the coil configuration and the neighboring HTS wires interact each other through the distorted magnetic field by the screening current Therefore, the AC loss of HTS magnet should be calculated using the whole configuration of the HTS magnet with superconducting characteristic. This paper describes the AC loss of the HTS magnet by an appropriate FEM approach, which uses the non-linear characteristic of HTS conductor. The analysis model is based on the 2-D FEM model, called as 'magnetic field formulation and edge-element model', for whole coil configuration in cylindrical coordinates. The effects of transport current and stacked conductors on the AC loss are investigated considering the field-dependent critical current. The PDE model of 'Comsol multiphysics' is used for the FEM analysis with properly implemented equations for axisymmetric model.

  5. FAST WINDS AND MASS LOSS FROM METAL-POOR FIELD GIANTS

    International Nuclear Information System (INIS)

    Echelle spectra of the infrared He I λ10830 line were obtained with NIRSPEC on the Keck 2 telescope for 41 metal-deficient field giant stars including those on the red giant branch (RGB), asymptotic giant branch (AGB), and red horizontal branch (RHB). The presence of this He I line is ubiquitous in stars with T eff∼> 4500 K and MV fainter than -1.5, and reveals the dynamics of the atmosphere. The line strength increases with effective temperature for T eff∼> 5300 K in RHB stars. In AGB and RGB stars, the line strength increases with luminosity. Fast outflows (∼> 60 km s-1) are detected from the majority of the stars and about 40% of the outflows have sufficient speed as to allow escape of material from the star as well as from a globular cluster. Outflow speeds and line strengths do not depend on metallicity for our sample ([Fe/H]= -0.7 to -3.0), suggesting the driving mechanism for these winds derives from magnetic and/or hydrodynamic processes. Gas outflows are present in every luminous giant, but are not detected in all stars of lower luminosity indicating possible variability. Mass loss rates ranging from ∼3 x 10-10 to ∼6 x 10-8 M sun yr-1 estimated from the Sobolev approximation for line formation represent values with evolutionary significance for red giants and RHB stars. We estimate that 0.2 M sun will be lost on the RGB, and the torque of this wind can account for observations of slowly rotating RHB stars in the field. About 0.1-0.2 M sun will be lost on the RHB itself. This first empirical determination of mass loss on the RHB may contribute to the appearance of extended horizontal branches in globular clusters. The spectra appear to resolve the problem of missing intracluster material in globular clusters. Opportunities exist for 'wind smothering' of dwarf stars by winds from the evolved population, possibly leading to surface pollution in regions of high stellar density.

  6. Self-field ac losses in biaxially aligned Y endash Ba endash Cu endash O tape conductors

    International Nuclear Information System (INIS)

    Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y endash Ba endash Cu endash O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the fourth power of transport current in the high Jc sample, and agreed well with Norris close-quote equation for thin strip conductors. However, the low Jc sample had rather higher losses than Norris close-quote prediction, suggesting excessive magnetic flux penetration caused by percolated current paths. The results confirmed Norris close-quote prediction of the low ac losses for thin strip conductors, and indicated the importance of removing percolated structures of current paths to avoid higher ac losses than the theoretical predictions based on uniform conductors. copyright 1997 American Institute of Physics

  7. An investigation of visual field test parameters in glaucoma, patterns of visual field loss in diabetics and multispectral imaging of the optic nerve head in glaucoma

    OpenAIRE

    Wang, Yanfang

    2013-01-01

    AbstractVisual field tests are routinely used for the detection and management of glaucoma. This thesis focuses on monitoring the vigilance during perimetry with pupil dynamics (pupillary movements, blinks) in glaucoma patients and the performance of using subsets of standard test patterns at detecting glaucomatous field loss. It describes the spatial pattern of visual field changes in diabetic retinopathy patients after treatment and the usage of multispectral imaging of the optic nerve head...

  8. The Effect of Wheat Straw, Corn Straw and Tobacco Residues on Denitrification Losses in a Field Planted with Wheat

    OpenAIRE

    COŞKAN, Ali; Gök, Mustafa; ONAÇ, Işık

    2002-01-01

    A field experiment was conducted to determine the effects of different organic residues (OR) (e.g., wheat straw corn straw and tobacco residues) on nitrogen mineralization and denitrification loss (N2O-N) using application rates recommended to local farmers. Nitrate and ammonium analyses were carried out on periodically collected soil samples. In-situ denitrification loss was determined using the acetylene inhibition technique (AIT). The results revealed that OR application increased N minera...

  9. Applying Theories and Interventions from Behavioral Medicine to Understand and Reduce Visual Field Variability in Patients with Vision Loss

    OpenAIRE

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

    2014-01-01

    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 ret...

  10. 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.

  11. Improved Eddy-current Field Loss Model and Scaling Index for Magnets of Permanent Magnet Synchronous Motors

    OpenAIRE

    Zhang Lei; Gao Chunxia

    2015-01-01

    The paper gives detailed systematic researches on the mechanism and key factors of eddy-current losses in rotor magnets of high power-density permanent magnet synchronous motors(PMSMs). Firstly, this paper establishes quantitative mathematic model of eddy-current losses for surface-mounted PMSM based on eddy current field model and Maxwell equations. Then, a scaling index is put forward to weigh the key factors relevant to the eddy-current losses in magnets. At the same time, the principles o...

  12. 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.

  13. 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

  14. Bryophyte diversity and range size distribution along two altitudinal gradients: Continent vs. island

    Science.gov (United States)

    Ah-Peng, Claudine; Wilding, Nicholas; Kluge, Juergen; Descamps-Julien, Blandine; Bardat, Jacques; Chuah-Petiot, Min; Strasberg, Dominique; Hedderson, Terry A. J.

    2012-07-01

    We compare patterns of bryophyte diversity and variation in species altitudinal ranges between a continental and an island altitudinal gradient. We use our ecological data set along the highest summit (Piton des Neiges, 3069 m) of Réunion Island (Mascarene archipelago) and compare it to available published data of another high volcanic massif in Colombia (Nevado del Ruiz, 5321 m). The distribution of narrow-ranged and large-ranged species was investigated. We tested the effect of geometric constraints on species distribution along the two gradients by comparing empirical to predicted data using the Mid-Domain Null Programme (McCain, 2004). Species richness was comparable between the island and continental gradient for epiphytic bryophytes, 265 and 295 species respectively. The comparison between the two tropical high mountains demonstrates important differences in the distribution of range sizes with altitude and a dominance of species with small range sizes on the Réunion gradient. For the island gradient, mean altitudinal range increases with altitude whilst concurrently species richness decreases revealing a Rapoport effect in altitudinal distribution of bryophyte communities. Geometric constraints did not explain much of the species richness pattern for the island. Conversely, for the continental gradient, dominated by large-ranged species, geometric constraints could not be ruled out as a primary structuring feature for the species richness pattern. This study also highlights that the island's cloud forest hosts not only high species richness but also high number of rare species, which is of prime interest for conservation planners.

  15. 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.

  16. Altitudinal variation of plant traits: morphological characteristics in Fragaria vesca L. (Rosaceae

    Directory of Open Access Journals (Sweden)

    Erika Maliníková

    2013-07-01

    Full Text Available The relationships among ecological conditions, morphological characteristics and total flavonoid content in Fragaria vesca L. species growing from the beech (710 m a.s.l. to dwarf pine altitudinal zone (1550 m a.s.l. in the western part of the Chocské vrchy Mts. (Western Carpathians were evaluated on 10 plots. Different habitats were studied using geobiocoenological typology system in order to investigate its ecology. It has been found out that F. vesca occurs in a variety of habitats with different trophic conditions (oligo-mesotrophic, mesotrophic, mesotrophic calciphile, nitrophilous calciphile and calciphile ranges and as a rule reached significantly higher values of measured parameters (number of leaves, length of the longest leaf, dry weight and total flavonoid content in the mesotrophic calciphile, mesotrophic and calciphile ranges of the 5th fir-beech and 8th dwarf pine altitudinal zones. On the other hand, average values of specific energy accumulated in strawberry leaves were significantly lower in calciphile conditions of the 4th beech and 8th dwarf pine altitudinal zones. From the measured parameters, mean number of leaves in strawberry rosettes and rosette weight were as a rule increasing from lower to higher altitudinal zones. The results of regression analysis confirm moderate positive linear relationship between these parameters and an altitude (R = 0.33. The flavonoid contents were as a rule decreasing from lower to higher altitudinal zones. The correlation of the flavonoid contents and an altitude was strong (R = 0.77. In the case of dependence rosette energy and length of the leaf on an altitude there were found out the regression relationships uncorrelated. 

  17. 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...

  18. Effect of superposing a DC-magnetic field on core loss of Mn-Zn ferrite; Mn-Zn ferrite no core loss ni okeru chokuryu jikai inka no koka

    Energy Technology Data Exchange (ETDEWEB)

    Takadate, K.; Yamamoto, Y.; Makino, A. [Alps Electric Co. Ltd., Tokyo (Japan)

    1998-06-01

    The effects of superposing a DC magnetic field on core loss of Mn-Zn ferrites were investigated. The core losses at 3 MHz are reduced to 56% by superposing a magnetic field of 2kOe perpendicularly to the magnetic path. The reduction of the core losses is mainly resulting from the decrease of the residual loss, which occupies a large part of the core loss at 3MHz. The magnetization of the samples becomes about 80% of the saturation magnetization by applying a magnetic field of 2kOe perpendicularly to the magnetic path. The decrease of the residual losses can be explained by the change of magnetization process from the domain wall displacement to the rotation magnetization with increasing the superposed DC magnetic field. 16 refs., 9 figs., 3 tabs.

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

    International Nuclear Information System (INIS)

    Based on two constants of motion, H and P/sub theta/, where H is the total energy of a particle and P/sub theta/ is the canonical angular momentum, particle confinement criteria are derived, which impose constraints on H and P/sub theta/. It is found that only a portion of (H,P/sub theta/) space, or equivalently, of velocity space, is for confinement. A loss region in velocity space is found. Effects of this loss region in velocity space ar investigated. The velocity-space particle loss due to collisions is calculated from the Fokker-Planck equation. The scaling law for particle confinement is obtained. It is shown that the VSPL model can account for the experimental observation in density profiles, particle confinement time, occurrence and spin-up of plasma rotation. Therefore, the VSPL has the possibility to be the dominent particle loss mechanism and the sole cause responsible for the observed plasma rotation in FRTP's

  20. AC loss in striped (filamentary) YBCO coated conductors leading to designs for high frequencies and field-sweep amplitudes

    International Nuclear Information System (INIS)

    AC losses of YBCO coated conductors are investigated by calculation and experiment for the higher frequency regime. Previous research using YBCO film deposited onto single-crystal substrates demonstrated the effectiveness of 'striping' or filamentary subdivision as a technique for AC loss reduction. As a result of these studies the idea of subdividing YBCO 'coated conductors' (YBCO, overlayer, and even underlayer) into such stripes suggested itself. The suggestion was implemented by burning grooves into samples of coated conductor using laser micromachining. Various machining parameters were investigated, and the striping and slicing characteristics are presented. Loss measurements were performed on unstriped as well as striped samples by the pick-up coil technique at frequencies from 50 to 200 Hz at field sweep amplitudes of up to 150 mT. The effect of soft ferromagnetic Fe shielding was also investigated. The results of the experiments form a starting point for a more general study of reduced-loss coated conductor design (including hysteretic, coupling, normal eddy current, and transport losses) projected into higher ranges of frequency and field-sweep amplitude with transformer and all-cryogenic-motor/generator applications in mind

  1. 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

  2. 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

  3. 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...... stage. The low altitudinal distribution limit of occurrences at the seedling life stage is, on average, 29 m higher than that at the adult life stage which is significant. The high altitudinal distribution limit also shows a similar trend but which is not significant. Complementary analyses using...... modelling techniques and focusing on the optimum elevation (i.e. the central position inside distribution ranges) have confirmed differences between life stages altitudinal distribution. Seedlings optima are mostly higher than adults optimum, reaching, on average, a 69 m gap. This overall trend showing...

  4. 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.

  5. 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...

  6. 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...

  7. The magnetisation profiles and ac magnetisation losses in a single layer YBCO thin film caused by travelling magnetic field waves

    Science.gov (United States)

    Wang, Wei; Coombs, Timothy

    2015-05-01

    This paper studies the magnetisation and ac magnetisation losses caused by a travelling magnetic wave on a single-layer YBCO thin film. This work provides thorough investigations on how the critical magnetic field gradient has been changed by the application of a travelling wave. Several conditions were studied such as zero-field cooling (ZFC), field cooling (FC) and a delta-shaped trapped field. It was found that the travelling wave tends to attenuate the existing critical magnetic field gradients in all these conditions. This interesting magnetic behaviour can be well predicted by the finite element (FEM) software with the E-J power law and Maxwell’s equations. The numerical simulations show that the existing critical current density has been compromised after applying the travelling wave. The magnetisation profile caused by the travelling wave is very different from the standing wave, while the magnetisation based on the standing wave can be interpreted by the Bean model and constant current density assumption. Based on the numerical method, which has reliability that has been solidly proven in the study, we have extended the study to the ac magnetisation losses. Comparisons were made between the travelling wave and the standing wave for this specific YBCO sample. It was found that by applying the magnetic wave of the same amplitude, the ac magnetisation loss caused by the travelling wave is about 1/3 of that caused by the standing wave. These results are helpful in understanding the general magnetism problems and ac magnetisation loss in the travelling magnetic wave conditions such as inside a high temperature superconducting (HTS) rotating machine, etc.

  8. Are altitudinal limits of equatorial stream insects reflected in their respiratory performance?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Brodersen, Klaus Peter

    2008-01-01

    .6 between genera at 17 °C, and from 1.3 to 2.5 at 5 °C. Q10 values for this temperature interval ranged 1.5-2.9 (mean 2.3). The two "high-altitude" genera had higher respiration rates at low temperature and oxygen saturation, and their respiration rate saturated at lower temperatures, than three of the four...... altitudinal limits of the six genera were not reflected in their respiratory performance, because all genera had critical minima of temperature and oxygen saturation much lower than those occurring at the limits of their natural distribution. So, the altitudinal limit could not be attributed to absolute short......-term physiological tolerance of low temperature and oxygen concentration. 5. Multiple regressions (based on respiration experiments and previously obtained relationships between water temperature, oxygen saturation and altitude) were used to predict how respiration rates should vary with altitude. At the upper limit...

  9. 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...

  10. Altitudinal variation of plant traits: morphological characteristics in Fragaria vesca L. (Rosaceae

    Directory of Open Access Journals (Sweden)

    Erika Maliníková

    2013-05-01

    Full Text Available The relationships among ecological conditions, morphologicalcharacteristics and total flavonoid content in Fragaria vesca L. species growing from the beech (710 m a.s.l. to dwarf pine altitudinal zone (1550 m a.s.l. in the western part of the Chočské vrchy Mts. (Western Carpathians were evaluated on 10 plots. Different habitats were studied using geobiocoenological typology system in order to investigate its ecology. It has been found out that F. vesca occurs in a variety of habitats with different trophic conditions (oligo-mesotrophic, mesotrophic, mesotrophic calciphile, nitrophilous calciphile and calciphile ranges and as a rule reached significantlyhigher values of measured parameters (number of leaves, length ofthe longest leaf, dry weight and total flavonoid content in the mesotrophic calciphile, mesotrophic and calciphile ranges of the 5th fir-beech and 8th dwarf pine altitudinal zones. On the other hand, average values of specific energy accumulated in strawberry leaves were significantly lower in calciphile conditions of the 4th beech and 8th dwarf pine altitudinal zones. From the measured parameters, mean number of leaves in strawberry rosettes and rosette weight were as a rule increasing from lower to higher altitudinal zones. The results of regression analysis confirm moderate positive linear relationship between these parameters and the altitude (R = 0.33. The flavonoidcontents were as a rule decreasing from lower to higher altitudinalzones. The correlation of the flavonoid contents and an altitude was strong (R = 0.77. In the case of dependence rosette energy and length of the leaf on an altitude there were found out the regression relationships uncorrelated.

  11. 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

  12. 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...

  13. 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.

  14. 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...

  15. Lingual and fusiform gyri in visual processing: a clinico-pathologic study of superior altitudinal hemianopia.

    OpenAIRE

    Bogousslavsky, J.; Miklossy, J; Deruaz, J P; Assal, G; Regli, F

    1987-01-01

    A macular-sparing superior altitudinal hemianopia with no visuo-psychic disturbance, except impaired visual learning, was associated with bilateral ischaemic necrosis of the lingual gyrus and only partial involvement of the fusiform gyrus on the left side. It is suggested that bilateral destruction of the lingual gyrus alone is not sufficient to affect complex visual processing. The fusiform gyrus probably has a critical role in colour integration, visuo-spatial processing, facial recognition...

  16. 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. ...

  17. 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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

    Zhao, Zhi-Gang; Wang, Yi-Ke

    2015-01-01

    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. PMID:25692295

  1. 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

  2. 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.

  3. Distribución altitudinal y diversidad de hemiparasitas y parasitas del orden santalales en el santuario de fauna y flora de iguaque boyacá (colombia)

    OpenAIRE

    Barrera T. Eduardo; Acosta H. Nelly

    2011-01-01

    The altitudinal distribution of 10 species of hemiparasitic and parasitic plants from 4 families to the Santalalean order has been studied along a transect of 9 Km from Villa de Leiva-Arcabuco road to San Pedro de Iguaque lagoon. Four altitudinal zones are distingued and briefly described on the basis of prominent characteristics. The relation with host species are analized as other observations. Gaiadendron punctatum offers the larger range of altitudinal distribution and presents the homoca...

  4. 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...

  5. Effectiveness of biological geotextiles in reducing runoff and soil loss under different environmental conditions using laboratory and field plot data

    Science.gov (United States)

    Smets, T.

    2009-04-01

    Preliminary investigations suggest biological geotextiles could be an effective and inexpensive soil conservation method, with enormous global potential. Biological geotextiles are a possible temporary alternative for vegetation cover and can offer immediate soil protection. However, limited data are available on the erosion-reducing effects of biological geotextiles. Therefore, the objective of this study is to evaluate the effectiveness of selected types of biological geotextile in reducing runoff and soil loss under controlled laboratory conditions and under field conditions reflecting different environments (i.e. continental, temperate and tropical). In laboratory experiments, interrill runoff, interrill erosion and concentrated flow erosion were simulated using various rainfall intensities, flow shear stresses and slope gradients. Field plot data on the effects of biological geotextiles on sheet and rill erosion were collected in several countries under natural rainfall (U.K., Hungary, Lithuania, South Africa, Brazil, China and Thailand). The laboratory experiments indicate that all tested biological geotextiles were effective in reducing interrill runoff (on average 59% of the value for bare soil) and interrill erosion rates (on average 16% of the value for bare soil). Since simulated concentrated flow discharge sometimes flowed below the geotextiles, the effectiveness in reducing concentrated flow erosion was significantly less (on average 59% of the value for bare soil). On field plots, where both interrill and rill erosion occur, all tested geotextiles reduced runoff depth by a mean of 54% of the control value for bare soil and in some cases, runoff depth increased compared to bare soil surfaces, which can be attributed to the impermeable and hydrophobic characteristics of some biological geotextiles. In the field, soil loss rates due to interrill and rill erosion were reduced by a mean of 21% of the value of bare soil by biological geotextiles. This study

  6. Recruitment of subalpine tree populations sensitive to warming within and above current altitudinal range

    Science.gov (United States)

    Kueppers, L. M.; Castanha, C.; Moyes, A. B.; Conlisk, E.; Germino, M. J.; Torn, M. S.; Harte, J.; Mitton, J.

    2014-12-01

    large lags between onset of climate changes and tree population responses. Linking field experiments directly with models of population change across the landscape provides a novel approach to projecting changes in altitudinal distributions of forest with climate change over time.

  7. Effect of a dc magnetic field on the microwave losses in MgB2 thin films

    International Nuclear Information System (INIS)

    The microwave surface impedance (Zs=Rs+iXs) of in situ MgB2 thin films was measured as a function of temperature and parallel dc magnetic field at several frequencies between 5.7 and 18.5 GHz using a dielectric resonator technique. The results are consistent with the expectations for a classical type-II superconductor and, consequently, quite different from those of the high-Tc cuprates. The films cooled in zero field revealed a clear indication of the lower critical field Bc1, with a small hysteresis around B≤Bc1. In higher fields (B>Bc1), the losses followed the Coffey-Clem and Brandt model, including the frequency dependences, whereas high-Tc Y-Ba-Cu-O films did not show a reasonable agreement with this model. Both the relatively high values of ΔXs/ΔRs ratio and their frequency dependence indicate a weak effect of flux creep on the measured microwave loss in MgB2 films. The temperature dependence of ΔXs/ΔRs ratio can be described by a microscopic pinning model for BCS superconductors

  8. Long-term loss rates of radioisotopes of cobalt, zinc, ruthenium, caesium and silver by Mytilus edulis under field conditions

    International Nuclear Information System (INIS)

    Long-term loss rates of cobalt, zinc, ruthenium, caesium and silver by Mytilus edulis soft parts as well as shells were measured under field conditions in the Mediterranean Sea at Monaco during a period of 13 months after experimental contamination. For all 5 elements, the loss could be described by two exponential functions for the soft parts and one for the shells. Biological half lives for the long-lived compartment ranged from ∼20 days for caesium to 100 - 200 days for cobalt, zinc, ruthenium and silver for soft parts as well as for shells. A comparison with results from similar experiments performed under very different environmental conditions in the Baltic Sea indicated that caesium and maybe silver had a faster turnover in the warm and saline Mediterranean, whereas loss rates for cobalt and zinc were comparable. It is argued, that reliable deduction of loss rates require experiments running over several months to a year, and it is pointed out that shorter term experiments - even up to 3 months - may give biased results. (author)

  9. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    Science.gov (United States)

    Maggi, F.; Gu, C.; Venterea, R.; Riley, W.; Oldenburg, C.

    2007-12-01

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- ions are released from agricultural fields to the environment is a key factor in controlling the green-house effect and water contamination, and assumes ever greater importance in view of the foreseen increase in biofuel, food, and fiber production. To address these issues we have developed a mechanistic model (TOUGHREACT-N) for various nitrification and denitrification pathways, multiple microbial biomass dynamics, heat and water flows, and various chemical reactions at local and kinetic equilibrium. The soil column is represented in a 1D framework, with hydraulic properties described by a water tension-saturation model. Biotic and abiotic reactions are assumed to follow Michaelis-Menten kinetics, while a consortium of several micro-organismal strains is assumed to follow multiple Monod growth kinetics accounting for electron donor, electron acceptor, and inhibitor concentrations. Water flow is modeled with the Darcy-Richards equation, while nutrient transport is modeled by Fickian advective and diffusive processes in both gaseous and liquid phases. Heat flow is modeled with the Fourier equation. Plant dynamics is taken into account by coupling TOUGHREACT-N with CERES to determine water and nutrient uptake, and soil carbon accumulation. TOUGHREACT-N was calibrated against field measurements to assess pathways of N losses following fertilization. A good agreement between field observations and model predictions was found. We identified two dominant time scales in the system response that depended on plants dynamics. Before plants have substantial impact on soil nutrients and moisture content, N losses are characterized by rapid increases as a function of water application

  10. 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.

  11. 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.

  12. Field Reconstruction in Sensor Networks with Coverage Holes and Packet Losses

    CERN Document Server

    Nordio, Alessandro

    2010-01-01

    Environmental monitoring is often performed through a wireless sensor network, whose nodes are randomly deployed over the geographical region of interest. Sensors sample a physical phenomenon (the so-called field) and send their measurements to a {\\em sink} node, which is in charge of reconstructing the field from such irregular samples. In this work, we focus on scenarios of practical interest where the sensor deployment is unfeasible in certain areas of the geographical region, e.g., due to terrain asperities, and the delivery of sensor measurements to the sink may fail due to fading or to transmission collisions among sensors simultaneously accessing the wireless medium. Under these conditions, we carry out an asymptotic analysis and evaluate the quality of the estimation of a d-dimensional field when the sink uses linear filtering as a reconstruction technique. Specifically, given the matrix representing the sampling system, V, we derive both the moments and an expression of the limiting spectral distribu...

  13. ac losses and field and current density distribution during a full cycle of a stack of superconducting tapes

    Science.gov (United States)

    Yuan, Weijia; Campbell, A. M.; Coombs, T. A.

    2010-05-01

    Starting from an existing model by Clem et al., this paper has analyzed how the current density and magnetic field distribution of a stack of superconducting tapes with ac transport currents or applied fields will change in a full cycle. This paper assumes when the ac current or field starts to change in the other direction, a new penetrated region will begin to penetrate from the superconductor surface. If we assume Jc is constant in the critical region, this paper demonstrates that the Claassen formula (7) can be used to calculate the exact ac losses. If Jc depends on local Bz, we can use Eq. (9) to quickly predict the ac losses. This approach does not need to calculate a complete ac cycle. This saves considerably computation time while gives a result which is in close agreement with that calculated from a complete ac cycle. The calculation method can be applied for calculating a superconducting pancake coil if the coil radius is much larger than the tape width.

  14. Do Plot Studies Generate “Directionally” Correct Assessments of Field Level Phosphorus Losses?

    Science.gov (United States)

    The National P Research Project (NPRP) coordinated a tremendous amount of research at the plot scale to assess the influence of nutrient management on P transport at the fields scale. The objectives of this research were to determine of plot scale rainfall simulations could be used to assess P trans...

  15. 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

  16. Field trip overview: habitat loss and plant invasions in northern Utah's Basin and Range

    Science.gov (United States)

    An all-day field trip was conducted on May 19, 2010, as part of the 16th Wildland Shrub Symposium program. The tour consisted of Tour A and Tour B, which visited Utah's west desert shrublands in Park Valley (Tour A), and Bear River Mountains montane shrublands and Hardware Ranch Wildlife Management...

  17. 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.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Omar Vergara-Diaz

    2015-06-01

    Full Text Available 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.

  20. Genetic responses to seasonal variation in altitudinal stress: whole-genome resequencing of great tit in eastern Himalayas.

    Science.gov (United States)

    Qu, Yanhua; Tian, Shilin; Han, Naijian; Zhao, Hongwei; Gao, Bin; Fu, Jun; Cheng, Yalin; Song, Gang; Ericson, Per G P; Zhang, Yong E; Wang, Dawei; Quan, Qing; Jiang, Zhi; Li, Ruiqiang; Lei, Fumin

    2015-01-01

    Species that undertake altitudinal migrations are exposed to a considerable seasonal variation in oxygen levels and temperature. How they cope with this was studied in a population of great tit (Parus major) that breeds at high elevations and winters at lower elevations in the eastern Himalayas. Comparison of population genomics of high altitudinal great tits and those living in lowlands revealed an accelerated genetic selection for carbohydrate energy metabolism (amino sugar, nucleotide sugar metabolism and insulin signaling pathways) and hypoxia response (PI3K-akt, mTOR and MAPK signaling pathways) in the high altitudinal population. The PI3K-akt, mTOR and MAPK pathways modulate the hypoxia-inducible factors, HIF-1α and VEGF protein expression thus indirectly regulate hypoxia induced angiogenesis, erythropoiesis and vasodilatation. The strategies observed in high altitudinal great tits differ from those described in a closely related species on the Tibetan Plateau, the sedentary ground tit (Parus humilis). This species has enhanced selection in lipid-specific metabolic pathways and hypoxia-inducible factor pathway (HIF-1). Comparative population genomics also revealed selection for larger body size in high altitudinal great tits. PMID:26404527

  1. Alternating current losses in stacked Bi2Sr2Ca2Cu3O10/Ag tapes in perpendicular magnetic fields

    International Nuclear Information System (INIS)

    Alternating current losses in stacks of powder-in-tube-processed Bi2Sr2Ca2Cu3O10/Ag tapes were measured in perpendicular magnetic fields and compared with calculated hysteresis losses based on the critical-state model. Four main factors had to be taken into account for the calculations of the losses: (1) the inclusion of the area of the Ag sheath in determining the critical-current densities of the stacks, (2) the zero-applied-field critical currents Ic(perpendicularsign)(0) with truly perpendicular fields only, not the standard self-field critical current IcS(0), and (3) the field-dependent critical current Ic(H), e.g., the Kim's model, and (4) the subtraction of the frequency-dependent losses at very high fields. With these considerations, the agreement between the calculated and the measured values of the losses is excellent for fields beyond the full-penetration fields. However, these factors did not totally account for the low-field losses. (c) 2000 American Institute of Physics

  2. Novo registro altitudinal de Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae no Brasil = New altitudinal record of Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae in Brazil

    Directory of Open Access Journals (Sweden)

    Samuel Campos Gomides

    2009-07-01

    Full Text Available Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae é uma espécie de caranguejo que habita rios e riachos montanhosos em altitudes até aproximadamente 500 m. Sua distribuição ocorre na América do Sul, desde as bacias costeiras da faixa leste do Brasil até a bacia do alto Paraná e na Argentina. O objetivo do presente trabalho foi registrar a ocorrência de T. fluviatilis em uma Unidade de Conservação de Juiz de Fora, Minas Gerais, e fornecer um novo registro altitudinal dessa espécie noBrasil. As amostras foram obtidas de outubro de 2004 a julho de 2005. Foram coletados três indivíduos vivos, dois machos e uma fêmea da espécie. Também foram analisados 16 regurgitos estomacais do cágado Hydromedusa maximiliani, dos quais, em seis foram encontrados partes corporais deste crustáceo. Muitas espécies de caranguejos do Brasil dafamília Trichodactylidae vivem em regiões acima de 500m do nível do mar. No presente estudo, T. fluviatilis foi coletado a 770 m de altitude, ampliando assim a faixa de distribuição altitudinal dessa espécie no Brasil. Até o presente estudo não existiam relatos de T. fluviatilis no município de Juiz de Fora, portanto este estudo também se constitui em um novo registro desse tricodatilídeo em Minas Gerais. Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae is a crab species that lives in mountainous rivers and streams at altitudes up to 500m. Its distribution ranges from South America from the Basins of eastern coast of Brazil to basins of the Upper Paraná River and Argentina. The main objective of this study was to register a new occurrence of T. fluviatilis at a Conservation Unit in Juiz de Fora, Minas Gerais and provide a new altitudinal record for this species in Brazil. The samples were taken between October 2004 and July 2005. We collected three live T. fluviatilis individuals – two males and one female. We also analyzed the stomach contents of 16

  3. 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...

  4. Optimized mode-field adapter for low-loss fused fiber bundle signal and pump combiners

    Czech Academy of Sciences Publication Activity Database

    Koška, Pavel; Baravets, Yauhen; Peterka, Pavel; Písařík, M.; Bohata, J.

    Vol. 9344. BELLINGHAM: SPIE, 2015 - (Ballato, J.; Shaw, L.), 93442I ISBN 978-1-62841-434-9. ISSN 0277-786X. [Conference on Fiber Lasers XII - Technology, Systems, and Applications. San Francisco (US), 09.02.2015-12.02.2015] R&D Projects: GA MPO FR-TI4/734 Institutional support: RVO:67985882 Keywords : Fiber laser * Mode-field adapter * Double clad fiber Subject RIV: BH - Optics, Masers, Lasers

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

    International Nuclear Information System (INIS)

    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. (orig.)

  6. 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...... 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...

  7. Understanding deposition rate loss in high power impulse magnetron sputtering: I. Ionization-driven electric fields

    International Nuclear Information System (INIS)

    The lower deposition rate for high power impulse magnetron sputtering (HiPIMS) compared with direct current magnetron sputtering for the same average power is often reported as a drawback. The often invoked reason is back-attraction of ionized sputtered material to the target due to a substantial negative potential profile, sometimes called an extended presheath, from the location of ionization toward the cathode. Recent studies in HiPIMS devices, using floating-emitting and swept-Langmuir probes, show that such extended potential profiles do exist, and that the electric fields Ez directed toward the target can be strong enough to seriously reduce ion transport to the substrate. However, they also show that the potential drops involved can vary by up to an order of magnitude from case to case. There is a clear need to understand the underlying mechanisms and identify the key discharge variables that can be used for minimizing the back-attraction. We here present a combined theoretical and experimental analysis of the problem of electric fields Ez in the ionization region part of HiPIMS discharges, and their effect on the transport of ionized sputtered material. In particular, we have investigated the possibility of a ‘sweet spot’ in parameter space in which the back-attraction of ionized sputtered material is low. It is concluded that a sweet spot might possibly exist for some carefully optimized discharges, but probably in a rather narrow window of parameters. As a measure of how far a discharge is from such a window, a Townsend product ΠTownsend is proposed. A parametric analysis of ΠTownsend shows that the search for a sweet spot is complicated by the fact that contradictory demands appear for several of the externally controllable parameters such as high/low working gas pressure, short/long pulse length, high/low pulse power and high/low magnetic field strength. (paper)

  8. 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).

  9. 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.

  10. 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

  11. 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...

  12. Changes of ecologicals conditions and factors in peak spruce stands of the 7 altitudinal vegetation zone

    OpenAIRE

    Juraj Nič

    2008-01-01

    Natural spruce stands of the Low Tatras and Poľana consist of communities of the 6th and the 7th altitudinal vegetation zone, mainly of the group of the forest type /gft/ Sorbeto Piceetum /SP/. In the year 2006, the repeated phytocoenological research was carried out on 48 areas under monitoring. These areas were founded in the year 1982. The goal of the research was to evaluate quantitative and qualitative changes of basic phytocoenoses, changes of abudance and dominance parameters of shelte...

  13. Altitudinal variation of plant traits: morphological characteristics in Fragaria vesca L. (Rosaceae)

    OpenAIRE

    Erika Maliníková; Ján Kukla; Margita Kuklová; Mária Balážová

    2013-01-01

    The relationships among ecological conditions, morphological characteristics and total flavonoid content in Fragaria vesca L. species growing from the beech (710 m a.s.l.) to dwarf pine altitudinal zone (1550 m a.s.l.) in the western part of the Chocské vrchy Mts. (Western Carpathians) were evaluated on 10 plots. Different habitats were studied using geobiocoenological typology system in order to investigate its ecology. It has been found out that F. vesca occurs in a variety of habitats with...

  14. 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

  15. 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

  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. Chromosomal inversion polymorphism in Drosophila mediopunctata: seasonal, altitudinal, and latitudinal variation

    Directory of Open Access Journals (Sweden)

    Ananina Galina

    2004-01-01

    Full Text Available The most polymorphic chromosome for inversions in Drosophila mediopunctata is the chromosome II, where 17 inversions have been found, eight of which occurring in the distal region and nine in the proximal region. We present an analysis of the chromosome II inversion polymorphism with respect to seasonal, altitudinal and latitudinal variation. In D. mediopunctata from the Parque Nacional do Itatiaia (southeastern Brazil, the frequencies of three of the distal inversions (namely DA, DS, and DP vary seasonally. These inversions also show altitudinal clines in their frequencies. This microgeographic pattern was not observed on a macrogeographic scale. D. mediopunctata from Porto Alegre are less polymorphic for inversions than other populations, the most remarkable reduction occurring in the proximal region of chromosome II. There is a considerable difference between D. mediopunctata from Campinas and specimens from Serra do Japi, which are separated by only 50 km. In contrast, D. mediopunctata from Serra do Japi are much more similar to specimens from the Parque Nacional do Itatiaia, which is 200 km far.

  18. [Photosynthesis in three altitudinal populations of the Andean plant Espeletia schultzii (Compositae)].

    Science.gov (United States)

    Castrillo, Marisol

    2006-12-01

    Photosynthesis was compared in three altitudinal populations of Espeletia schultzii: 3,100, 3,550 and 4,200 masl. The measured parameters were Rubisco activity (EC 4.1.139), chlorophyll, soluble protein and soluble sugars contents, and specific leaf area (SLA). The 4,200 m population had a higher Rubisco activity (at 4 degrees C) followed by those at 3,550 m and 3,100 m. There were no significant differences between populations at 3,100 m and 3,550 m (ANOVA), but their activities were different from those of the 4,200 m population. Chlorophyll a content decreased slightly with elevation, while chlorophyll b was constant; therefore, the Ra/b ratio decreased with elevation, but not significantly. The leaf soluble sugars content increased along the altitudinal gradient. Leaf protein content did not differ. The SLA decreased with altitude. The increase in Rubisco activity might reflect higher enzyme activation and not higher enzyme protein. The increase in soluble sugars is probably associated to Rubisco activity. Three out of the five measured parameters revealed differences with altitude, suggesting a compromise between a higher metabolic activity and a smaller cellular volume. PMID:18457152

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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...... 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...... of application). Furthermore, the standard climatic conditions (e.g. temperature, precipitation) as well as soil moisture and temperature to a depth of approx. 2 meter were measured. Concentrations of nitrate in the drainage and groundwater, recharge of water through the drainage system as well as depth...

  6. 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

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

    International Nuclear Information System (INIS)

    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 MgB2 generator rotor coil. - Abstract: 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 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 MgB2 DC coils in the 1–4 T range with low AC magnetic field and current ripples

  8. 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

  9. 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.

  10. Amphibia, Anura, Strabomantidae, Geobatrachus walkeri (Ruthven, 1915): Altitudinal extension and new habitat, Colombia.

    OpenAIRE

    Rueda-Solano, L. A.; Vargas-Salinas, F.

    2010-01-01

    In September 2008 we registered the frog Geobatrachus walkeri at ~ 3500 m elevation in the Sierra Nevada deSanta Marta, an isolated mountain range in the Caribbean Colombian, South America. Our record expands the knowledge ofthe altitudinal distribution of this species on 700 m and constitutes the first observation in páramo habitat.

  11. 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

  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. Electromagnetic ion-cyclotron instability in the presence of a parallel electric field with general loss-cone distribution function - particle aspect analysis

    OpenAIRE

    G. Ahirwar; P. Varma; M. S. Tiwari

    2006-01-01

    The effect of parallel electric field on the growth rate, parallel and perpendicular resonant energy and marginal stability of the electromagnetic ion-cyclotron (EMIC) wave with general loss-cone distribution function in a low β homogeneous plasma is investigated by particle aspect approach. The effect of the steepness of the loss-cone distribution is investigated on the electromagnetic ion-cyclotron wave. The whole plasma is considered to consist of resonant and non-resonant particl...

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

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2003-01-01

    that among streams within regions. The mean number of families was 8.2, 4.9 and 4.1 per stone, 26.5, 19 and 13.3 per locality (stream), and 44, 37 and 27 per region at the three altitudes, respectively. Thus, both local and regional richness decreased approximately linearly with increasing altitude......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...... of Ecuador. Stream sites were characterised by a number of physico-chemical parameters and the fauna by several indices of richness, diversity and evenness. A MDS ordination on the composition of the fauna clearly separated the streams in three groups according to altitude. The invertebrate fauna...

  16. Social wasp communities (Hymenoptera Vespidae at different altitudinal levels in southern Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Humberto Bueno de Albuquerque

    2015-12-01

    Full Text Available Various studies have described changes in richness and abundance of insect groups along altitudinal gradients, but there is little information about social wasps (Hymenoptera, Vespidae in this regard. This study evaluated the influence of altitude on the diversity of these insects in fragments of semideciduous forest in a tropical altitude climate. Three different elevations in southern Minas Gerais, from 997 to 2080 meters, were studied. Sampling was carried out on 24 days in a ten-month period by active collection. A total of 34 species were found, distributed in 11 genera. At Level 01, 27 species were recorded, and at Level 02, there were 19 species, while Level 03 showed 11 species. The most frequent genus in the sudy area was Polybia, This study showed that in high-altitude tropical climate areas above 1800 meters, diversity decreases substantially and that the number of species that nest by swarming and build nests with protective cover increases.

  17. Genetic features of soils in altitudinal natural zones of the Khibiny Mountains

    Science.gov (United States)

    Pereverzev, V. N.

    2010-05-01

    The plant cover of the Khibiny Mountains is characterized by the well-pronounced altitudinal zonality: high-alpine barrens—lichen, dwarf shrub, and shrub tundra—elfin birch forest—spruce forest. Humic petrozems (Lithic Leptosols) under sparse vegetation are formed on the tops of the mountains. The soils of the tundra zone are represented by podburs on the eluvium of nepheline syenite; smaller areas are occupied by typical cryozems. Humus-illuvial podzols are developed from moraine deposits under elfin birch forests and open spruce woodland. The moraine deposits in the inner valleys of the Khibiny Mountains are enriched in the products of weathering of nepheline syenite. The humus-illuvial podzols developed from them differ from their analogues on plain territories in the higher humus content and less contrasting eluvialilluvial differentiation.

  18. Altitudinal and seasonal differences of tick communities in dogs from pastoralist tribes of Northern Kenya.

    Science.gov (United States)

    D'Amico, Gianluca; Dumitrache, Mirabela O; Široký, Pavel; Albrechtová, Kateřina; Sloboda, Michal; Domşa, Cristian; Sándor, Attila D; Balázsi, Robert; Kanyari, Paul W N; Modrý, David; Mihalca, Andrei D

    2015-09-15

    Studies regarding the distribution and ecology of ticks in dogs from Eastern Africa are scarce. Our research was based on a long-term screening of ticks parasitising the domestic dogs living with indigenous people around Lake Turkana, Mt. Kulal and Mt. Nyiru areas, Northern Kenya. A total of 9977 ticks were collected from 1464 dogs of all ages and both sexes. Identification was performed using morphological keys and data were analyzed using the Repeated Measures ANOVA, post-hoc Scheffe test and F test, relating independent variables as seasons and regions. Final results were translated to maps using GIS software. Five species of ticks were identified: Rhipicephalus pulchellus, Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus armatus, Amblyomma gemma and Hyalomma truncatum. Our results suggest a statistical difference of the tick community structure related to seasonal and altitudinal distribution. Parasitism with R. armatus and R. pulchellus was higher in September-October than in January, whereas, R. sanguineus s.l. was not influenced by the season. Rhipicephalus armatus was present exclusively on dogs living in semi-desert areas, while R. sanguineus s.l. was the dominant species present on the shores of Lake Turkana. Although R. pulchellus was present in the all studied areas, this species had a significantly higher abundance in the afromontane region of Mt. Kulal and montane xeromorphic forest of Mt. Nyiru; these regions are characterized by elevated humidity and cooler climate. Similar geo-climatic distribution is typical also for A. gemma, which was found in dogs exclusively in Mt. Kulal afromontane area. The current work represents the most extensive study performed on the tick community structure of dogs in Eastern Africa. The results showed a relatively limited tick species diversity, with clear seasonal differences and altitudinal distribution. PMID:26343303

  19. 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...

  20. Charge losses in silicon sensors and electric-field studies at the Si-SiO2 interface

    International Nuclear Information System (INIS)

    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 μm 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 SiO2 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-SiO2 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-SiO2 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 added to the accumulation

  1. 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

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Species composition, seasonal occurrence, habitat preference and altitudinal distribution of malaria and other disease vectors in eastern Nepal

    OpenAIRE

    Dhimal, Meghnath; Ahrens, Bodo; Kuch, Ulrich

    2014-01-01

    Background It is increasingly recognized that climate change can alter the geographical distribution of vector-borne diseases (VBDs) with shifts of disease vectors to higher altitudes and latitudes. In particular, an increasing risk of malaria and dengue fever epidemics in tropical highlands and temperate regions has been predicted in different climate change scenarios. The aim of this paper is to expand the current knowledge on the seasonal occurrence and altitudinal distribution of malaria ...

  8. 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...

  9. 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

  10. 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.

  11. 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

  12. Identification of radio-frequency and microwave residual-loss mechanisms in YBa2Cu3O7-δ films in a magnetic field

    International Nuclear Information System (INIS)

    The RF and microwave response of YBa2Cu3O7-δ films on BaxSr1-xTiO3/MgO substrates was investigated in an external static magnetic field. Films with a varying thickness, orientation and type of structure were studied in order to understand the mechanisms of RF and microwave residual losses. The measurements of surface resistance (R) as a function of the film thickness and static (H) and RF (H∼) magnetic field are discussed. Analysis of theoretical and experimental R(H) dependences has shown that residual RF and microwave losses occur in a static magnetic field on Josephson junctions formed at grain boundaries and at microblock boundaries with trapped Abrikosov vortices and on Abrikosov vortices themselves, and are also caused by non-superconductive inclusions. (author)

  13. 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).

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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

    2015-12-01

    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

  19. Enhancing the Efficacy of Teacher Incentives through Loss Aversion: A Field Experiment. NBER Working Paper No. 18237

    Science.gov (United States)

    Fryer, Roland G., Jr.; Levitt, Steven D.; List, John; Sadoff, Sally

    2012-01-01

    Domestic attempts to use financial incentives for teachers to increase student achievement have been ineffective. In this paper, we demonstrate that exploiting the power of loss aversion--teachers are paid in advance and asked to give back the money if their students do not improve sufficiently--increases math test scores between 0.201 (0.076) and…

  20. Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking.

    Directory of Open Access Journals (Sweden)

    Enkelejda Kasneci

    Full Text Available Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs that may critically interfere with quality of life and driving licensure. The aims of this study were (i to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed of ten patients with homonymous visual field defects (HP, including four patients with right (HR and six patients with left homonymous visual field defects (HL, ten glaucoma patients (GP, and twenty age and gender-related ophthalmologically healthy control subjects (C during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on

  1. Tile drain losses of nitrogen and phosphorus from fields under integrated and organic crop rotations. A four-year study on a clay soil in southwest Sweden.

    Science.gov (United States)

    Stenberg, Maria; Ulén, Barbro; Söderström, Mats; Roland, Björn; Delin, Karl; Helander, Carl-Anders

    2012-09-15

    In order to explore the influence of site-specific soil properties on nitrogen (N) and phosphorus (P) losses between individual fields and crop sequences, 16 drained fields with clay soils were investigated in a four-year study. Mean total N (TN) loss was 6.6-11.1 from a conventional, 14.3-21.5 from an organic and 13.1-23.9 kg ha(-1) year(-1) from an integrated cropping system across a 4 year period, with 75% in nitrate form (NO(3)-N). Mean total P (TP) loss was 0.96-3.03, 0.99-4.63 and 0.76-2.67 kg ha(-1) year(-1), from the three systems respectively during the same period, with 25% in dissolved reactive form (DRP). Median N efficiency was calculated to be 70% including gains from estimated N fixation. According to principal component factor (PCA) analysis, field characteristics and cropping system were generally more important for losses of N and P than year. Accumulation of soil mineral N in the autumn and (estimated) N fixation was important for N leaching. No P fertilisers were used at the site in either cropping system. Total P concentration in drainage water from each of the fields was marginally significantly (pcrop with efficient nutrient uptake and good soil structure was general preconditions for low nutrient leaching. Incorporation of ley by tillage operations in the summer before autumn crop establishment and repeated operations in autumn as well, increased N leaching. Crop management in sequences with leguminous crops needs to be considered carefully when designing cropping systems high efficiency in N utilisation and low environmental impact. PMID:22264921

  2. 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 ...

  3. Distribución altitudinal y diversidad de Hemiparasitas y Parasitas del orden santalales en el santuario de fauna y flora de Iguaque Boyacá (Colombia

    Directory of Open Access Journals (Sweden)

    Barrera T. Eduardo

    1995-11-01

    Full Text Available The altitudinal distribution of 10 species of hemiparasitic and parasitic plants from 4 families to the Santalalean order has been studied along a transect of 9 Km from Villa de Leiva-Arcabuco road to San Pedro de Iguaque lagoon. Four altitudinal zones are distingued and briefly described on the basis of prominent characteristics. The relation with host species are analized as other observations. Gaiadendron punctatum offers the larger range of altitudinal distribution and presents the homocaule phenomenon in roots. Phoradendron pomasquianum is reported for the first time to Colombia and Phthirusa sp. is announced as a new record.En un transecto de 9 Km desde la vía Villa de Leiva-Arcabuco hasta la laguna de San Pedro de Iguaque, se reconocen 10 especies de hemiparásitas y parásitas pertenecientes a 4 familias del orden Santalales, se establece la distribución altitudinal de las especies. Se distinguen 4 zonas altitudinales y se describen brevemente. Se analiza la relación con los hospederos y otros aspectos observados. Gaiadendron punctatum presenta el mayor rango de distribución altitudinal y muestra en sus rafees el fenómeno de homocaulia. Phoradendron pomasquianum se reporta por primera vez para Colombia y Phthirusa sp. se anuncia como nuevo registro.

  4. Distribution of grasses along an altitudinal gradient in a Venezuelan paramo Distribución de gramíneas a lo largo de un gradiente altitudinal en un páramo de Venezuela

    Directory of Open Access Journals (Sweden)

    EDJULY J. MÁRQUEZ

    2004-12-01

    Full Text Available In Venezuelan paramos grasses, after Asteraceae, are the second family in numerical importance. We studied their distribution in an altitudinal gradient located in Venezuela, Sierra de La Culata, between 2,500 and 4,200 m of altitude. Twenty one 32 m parallel line transects every 50 m were placed along the gradient, perpendicular to the main slope. Each line was divided into contiguous 50 x 50 cm sampling units. Grass species occurrence inside each sample unit was considered to determine their frequency in each line or altitude. The peak and altitudinal amplitude was determined through the weighted averaging method. A total of 47 grass species were found along the gradient. Agrostis was the best-represented genus in the gradient. Considering the distribution ranges, we assume that there are different biotic and abiotic processes determining the distribution patterns. The species occurring at the highest altitudes were temperate elements, while those in the lowest areas were tropical and subtropical elements. Seven species in the gradient are endemic to the Venezuelan paramos. Grass distribution patterns in the paramo may be related to phytogeographical origin. In order to better understand the plant altitudinal distribution pattern is necessary to consider the plant responses to low temperatures, high incoming radiation, water stress and slope aspectEn los páramos de Venezuela las gramíneas son la segunda familia numéricamente más importante, después de las Asteraceae. Nosotros estudiamos su distribución en un gradiente altitudinal ubicado en Venezuela, Sierra de La Culata, entre 2.500 y 4.200 m de altitud. Para esto colocamos 21 transectas de 32 m de longitud a lo largo del gradiente, ubicados de manera perpendicular a la pendiente, cada 50 m en altitud. Cada transecta estaba dividida en unidades de muestreo contiguas de 50 x 50 cm. Para estimar la frecuencia de las especies en cada transecta o altitud, consideramos la ocurrencia de las

  5. Electromagnetic ion-cyclotron instability in the presence of a parallel electric field with general loss-cone distribution function - particle aspect analysis

    Directory of Open Access Journals (Sweden)

    G. Ahirwar

    2006-08-01

    Full Text Available The effect of parallel electric field on the growth rate, parallel and perpendicular resonant energy and marginal stability of the electromagnetic ion-cyclotron (EMIC wave with general loss-cone distribution function in a low β homogeneous plasma is investigated by particle aspect approach. The effect of the steepness of the loss-cone distribution is investigated on the electromagnetic ion-cyclotron wave. The whole plasma is considered to consist of resonant and non-resonant particles. It is assumed that resonant particles participate in the energy exchange with the wave, whereas non-resonant particles support the oscillatory motion of the wave. The wave is assumed to propagate parallel to the static magnetic field. The effect of the parallel electric field with the general distribution function is to control the growth rate of the EMIC waves, whereas the effect of steep loss-cone distribution is to enhance the growth rate and perpendicular heating of the ions. This study is relevant to the analysis of ion conics in the presence of an EMIC wave in the auroral acceleration region of the Earth's magnetoplasma.

  6. Control of Mars global atmospheric loss by the continuous rotation of the crustal magnetic field: A time-dependent MHD study

    Science.gov (United States)

    Fang, Xiaohua; Ma, Yingjuan; Brain, David; Dong, Yaxue; Lillis, Robert

    2015-12-01

    We present a time-dependent MHD study of the controlling effects of the Mars crustal field on atmospheric escape. We calculate globally integrated planetary ion loss rates under quiet solar conditions considering the continuous rotation of crustal anomalies with the planet. It is found that the rotating crustal field plays an important role in controlling atmospheric escape. Significant time variation of ˜20% and ˜50% is observed during the entire rotation period for O+ and for O2+ and CO2+, respectively. The control is exerted mainly through two processes. First, the crustal magnetic pressure over the subsolar regime controls solar wind penetration and mass loading and therefore the escaping planetary ion source. There is a strong negative correlation between the magnetic pressure and ion loss, with a time lag of change in day-night connection regulates the extent to which planetary ions created on the dayside can be ultimately carried away by the solar wind and escape Mars. There is a strong positive correlation between the cross-section area and ion loss, with no significant time lag. As the planet rotates, the dayside process and the terminator process work together to control the total amount of escaping planetary ions. However, their relative importance changes with the local time of the strong crustal field region.

  7. 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.

  8. 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.

  9. Influence of Stator-Current Zero Sequence on Magnetic Field and Stray Losses in Induction Machine under Emergency Operation

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav

    Pilsen : University of West Bohemia, 2005, E39-E44. ISBN 80-7043-392-2. [International Conference on Advanced Methods in the Theory of Electrical Engineering /7./ (AMTEE'05). Plzeň (CZ), 12.09.2005-14.09.2005] R&D Projects: GA ČR(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction motor * emergency operation * stray losses Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Microclimatic variation in multiple Salamandra algira populations along an altitudinal gradient: phenology and reproductive strategies

    Directory of Open Access Journals (Sweden)

    Daniel Escoriza

    2014-06-01

    Full Text Available Salamandra algira is one of the southernmost species of the genus, and most of its ecology remains poorly known. We studied the microhabitat conditions of the sites occupied by several populations of S. algira along an altitudinal gradient, and the use of water bodies for reproduction. The microclimate conditions were analysed at six sites in northern Morocco: one site in Beni Snassen massif (S. algira spelaea, two in the Middle Atlas and central Rif mountains (S. algira splendens, and three in the western Rif mountains and Peninsula Tingitana (S. algira tingitana, where a viviparous population also occurs. The microclimate was characterized using temperature and relative humidity data loggers for a period of two years. We also measured the surface area and depth of the water bodies where we found S. algira larvae. Our results showed an autumn-winter reproductive period for all ovoviviparous populations studied. In most of the aquatic habitats examined, larvae appeared between November and March, although this period could extend to May at higher altitudes. Larval abundance and their size variability did not correlate with water body size or microclimate conditions. The decrease in the number of larvae per water body coincided with the existence of suitable conditions for post-metamorphic dispersal. Salamandra algira occurred in regions with moist conditions (annual average relative humidity greater than 64 % and with mean annual temperatures of 13.6-18.6 °C, but populations were largely segregated along a gradient of humidity, with some showing higher and more constant values than others. The viviparous population occurs in a region with maritime influence and greater microclimate stability than the other sites studied.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Nathaniel A. Lyngwi

    2013-03-01

    Full Text Available 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 Proteobacteria 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

  17. 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.

  18. Influence of Frequency and Induction of Longitudinal Magnetic Field on The Electrode Metal Loss and its Spattering During MAG-Welding

    Science.gov (United States)

    Nosov, D. G.; Peremitko, V. V.

    2015-09-01

    It is possible to increase the MAG-welding efficiency by controlling the electrode metal mass transfer at the reduction of discharge coefficient on spattering by influence of longitudinal magnetic field on the arc. The paper identifies a range of longitudinal magnetic field frequencies and induction which provide the discharge coefficient reduction of the electrode metal; it has also been found the characteristics of their mutual influence on electrode metal mass transfer process; mathematical models correlating the frequency and induction of longitudinal magnetic field length with loss coefficient of electrode metal on spattering are presented; technological recommendations, the implementation of which will allow to improve the efficiency of MAG-welding in industrial environments, are given.

  19. 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

    International Nuclear Information System (INIS)

    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. (paper)

  20. 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...

  1. 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.

  2. 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.

  3. Distribution of oribatid mites (Acari: Oribatida) along an altitudinal profile of Mount Vud'yavrchorr (the Khibiny Mountains)

    Science.gov (United States)

    Leonov, V. D.; Rakhleeva, A. A.; Sidorchuk, E. A.

    2015-11-01

    The species composition and distribution of oribatid mites by altitudinal zones of the northeastern slope of Vud'yavrchorr Mount in the Khibiny Mountains were studied. Fifty-two species of oribatids from 30 genera and 20 families were found; 21 species were found in the Khibiny region for the first time. The maximum number of species (33) were found in the mountainous taiga zone under herbaceous-dwarf-shrub spruce forest. Maximum values of population density (more than 190000 per m2) were recorded in the forest-tundra zone under crooked birch forest. Minimum values of population density and species diversity of oribatids were found in tundra ecotopes, especially in the area of lichen tundra. However, maximum values of the indices of oribatid diversity and evenness of oribatid taxocene were recorded under dwarf- birch tundra. The analysis of relationships between the representatives of different morphoecotypes of oribatid mites in the studied altitudinal zones demonstrated that the relative portion of carabodoid species regularly increases with the altitude.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. Dissolved organic carbon in headwater streams and riparian soil organic carbon along an altitudinal gradient in the Wuyi Mountains, China.

    Directory of Open Access Journals (Sweden)

    Wei Huang

    Full Text Available Stream water dissolved organic carbon (DOC correlates positively with soil organic carbon (SOC in many biomes. Does this relationship hold in a small geographic region when variations of temperature, precipitation and vegetation are driven by a significant altitudinal gradient? We examined the spatial connectivity between concentrations of DOC in headwater stream and contents of riparian SOC and water-soluble soil organic carbon (WSOC, riparian soil C:N ratio, and temperature in four vegetation types along an altitudinal gradient in the Wuyi Mountains, China. Our analyses showed that annual mean concentrations of headwater stream DOC were lower in alpine meadow (AM than in subtropical evergreen broadleaf forest (EBF, coniferous forest (CF, and subalpine dwarf forest (SDF. Headwater stream DOC concentrations were negatively correlated with riparian SOC as well as WSOC contents, and were unrelated to riparian soil C:N ratio. Our findings suggest that DOC concentrations in headwater streams are affected by different factors at regional and local scales. The dilution effect of higher precipitation and adsorption of soil DOC to higher soil clay plus silt content at higher elevation may play an important role in causing lower DOC concentrations in AM stream of the Wuyi Mountains. Our results suggest that upscaling and downscaling of the drivers of DOC export from forested watersheds when exploring the response of carbon flux to climatic change or other drivers must done with caution.

  9. 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...

  10. 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.

  11. 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

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

    Directory of Open Access Journals (Sweden)

    Nathaniel A. Lyngwi

    2013-03-01

    Full Text Available 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 Proteobacteria 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

  13. Very low field ac-response at the loss of long range magnetic order in amorphous Fe90Zr10

    International Nuclear Information System (INIS)

    Low temperature ac-susceptibility measurements over 5 decades of ac-field (0.08-8000 A/m) have been carried out on amorphous ribbons of Fe90Zr10 and Fe91Zr9. The authors find that at very low fields (0.8 to 24 A/m) ac-response measurements eliminate the influence of domain and domain wall motion, the well known Hopkinson peak effects, to reveal clearly the reentrant characteristics. With such studies a reentrant freezing temperature Taf is unambiguously revealed with an evident knee in χ'(T) and a corresponding well defined peak in χ double-prime(T). The latter is found to be independent of the applied field (0.8 to 8 A/m) while being weakly dependent on the frequency (10--1,000 Hz). They thus find Tsf to be 25 K and 40 K respectively for Fe90Zr10 and Fe91Zr9 amorphous ribbons

  14. Comparison of AC losses, magnetic field/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors

    International Nuclear Information System (INIS)

    A model is presented for calculating the AC losses, magnetic field/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper gives an exact circular coil model using elliptic integrals. A new efficient numerical method is introduced to yield more accurate and fast computation. The computation results are in good agreement with the assumptions. For a small value of the coil radius, there is an asymmetry along the coil radius direction. As the coil radius increases, this asymmetry will gradually decrease, and the AC losses and penetration depth will increase, but the critical current will decrease. We find that if the internal radius is equal to the winding thickness, the infinitely long stack approximation overestimates the loss by 10% and even if the internal radius is reduced to zero, the error is still only 60%. The infinitely long stack approximation is therefore adequate for most practical purposes. In addition, the comparison result shows that the infinitely long stack approximation saves computation time significantly.

  15. Comparison of AC losses, magnetic field/current distributions and critical currents of superconducting circular pancake coils and infinitely long stacks using coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Weijia; Campbell, A M; Hong, Z; Ainslie, M D; Coombs, T A, E-mail: wy215@cam.ac.u [Electronic, Power and Energy Conversion Group, Electrical Engineering Division, Engineering Department, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2010-08-15

    A model is presented for calculating the AC losses, magnetic field/current density distribution and critical currents of a circular superconducting pancake coil. The assumption is that the magnetic flux lines will lie parallel to the wide faces of tapes in the unpenetrated area of the coil. Instead of using an infinitely long stack to approximate the circular coil, this paper gives an exact circular coil model using elliptic integrals. A new efficient numerical method is introduced to yield more accurate and fast computation. The computation results are in good agreement with the assumptions. For a small value of the coil radius, there is an asymmetry along the coil radius direction. As the coil radius increases, this asymmetry will gradually decrease, and the AC losses and penetration depth will increase, but the critical current will decrease. We find that if the internal radius is equal to the winding thickness, the infinitely long stack approximation overestimates the loss by 10% and even if the internal radius is reduced to zero, the error is still only 60%. The infinitely long stack approximation is therefore adequate for most practical purposes. In addition, the comparison result shows that the infinitely long stack approximation saves computation time significantly.

  16. The effects of partial insulation winding on the charge–discharge rate and magnetic field loss phenomena of GdBCO coated conductor coils

    International Nuclear Information System (INIS)

    GdBCO single-pancake coils wound with Kapton insulation every 3, 6, 9 turns, and without insulation, were characterized by charge–discharge and over-current tests. The magnetic field saturation at higher currents than the critical current was affected by the portion of the insulated turns that restricted the surplus current flow away from the azimuthal current path. The charge–discharge delay decreased with the increase of the portion of the insulated turns, which suggested that partial insulation winding may be effective for use in HTS power applications. Magnetic field loss of the coils with reduced insulation at excessive high currents was mainly affected by the decrease in ampere-turns due to the electrically shorted-circuits between the non-insulated turns, which resulted in the over-current flow bypass through the turn-to-turn contacts. (paper)

  17. 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

  18. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    Science.gov (United States)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  19. Distribution pattern of the threatened Himalayan serow (Capricornis thar) in western midhills of Nepal. An insight for conservation along an altitudinal gradient

    Czech Academy of Sciences Publication Activity Database

    Paudel, Prakash K.; Kindlmann, Pavel

    2012-01-01

    Roč. 20, č. 3 (2012), s. 177-180. ISSN 1617-1381 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Capricornis thar * Himalayan serow * Nepal * Midhills * Habitat fragmentation * Altitudinal gradient Subject RIV: EH - Ecology, Behaviour Impact factor: 1.535, year: 2012

  20. 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., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}v_{*}^2\\simeq-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander.

    Science.gov (United States)

    Pereira, Ricardo J; Martínez-Solano, Iñigo; Buckley, David

    2016-04-01

    Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change. PMID:26850834

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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 ...

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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...

  2. Leaf morphology and phenology of Beech (Fagus sylvatica L.) are linked to environmental conditions depending on the altitudinal origin

    Science.gov (United States)

    Capdevielle-Vargas, Renee; Schuster, Christina; Estrella, Nicole; Menzel, Annette

    2014-05-01

    differences in SLA were found among the altitudinal levels in any of the transects, significant differences were found in biomass among the two highest sites of the two transects. The length of the lamina differed significantly between 900 to 1100-1400 m.a.s.l. in the south facing transect, while in the north facing transect the lamina width showed significant differences between the highest and the lower sites. A higher percentage of germination of seeds originating from higher altitudinal sites may points to a developed sensitivity to environmental changes and a rapid and more favorable response. Our results suggest, contrary to what has been reported, (leaf size differentiation among altitudinal sites under natural conditions), that the altitude of origin doesn't have an overriding impact on leaf morphological responses when growing under the same conditions, indicating that leaf morphology and phenology may have an adaptive significance linked to climate.

  3. 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

  4. 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

  5. Hidden loss

    DEFF Research Database (Denmark)

    Kieffer-Kristensen, Rikke; Johansen, Karen Lise Gaardsvig

    2013-01-01

    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...

  6. 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%.

  7. 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.

  8. 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

  9. 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.

  10. [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

  11. 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 ...

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. Density and community structure of soil- and bark-dwelling microarthropods along an altitudinal gradient in a tropical montane rainforest.

    Science.gov (United States)

    Illig, Jens; Norton, Roy A; Scheu, Stefan; Maraun, Mark

    2010-09-01

    Microarthropod communities in the soil and on the bark of trees were investigated along an elevation gradient (1,850, 2,000, 2,150, 2,300 m) in a tropical montane rain forest in southern Ecuador. We hypothesised that the density of microarthropods declines with depth in soil and increases with increasing altitude mainly due to the availability of resources, i.e. organic matter. In addition, we expected bark and soil communities to differ strongly, since the bark of trees is more exposed to harsher factors. In contrast to our hypothesis, the density of major microarthropod groups (Collembola, Oribatida, Gamasina, Uropodina) was generally low and decreased with altitude. However, as we predicted the density of each of the groups decreased with soil depth. Density of microarthropods on tree bark was lower than in soil. Overall, 43 species of oribatid mites were found, with the most abundant higher taxa being Poronota, pycnonotic Apheredermata, Mixonomata and Eupheredermata. The oribatid mite community on bark did not differ significantly from that in soil. The number of oribatid mite species declined with altitude (24, 23, 17 and 13 species at 1,850, 2,000, 2,150 and 2,300 m, respectively). Rarefaction curves indicate that overall about 50 oribatid mite species are to be expected along the studied altitudinal gradient. Results of this study indicate (1) that microarthropods may be limited by the quality of resources at high altitudes and by the amount of resources at deeper soil layers, and (2) that the bark of trees and the soil are habitats of similar quality for oribatid mites. PMID:20229099

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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 ...

  4. Convergence of morphological, biochemical, and physiological traits of upper and lower canopy of European beech leaves and Norway spruce needles within altitudinal gradients

    Czech Academy of Sciences Publication Activity Database

    Rajsnerová, Petra; Klem, Karel; Večeřová, Kristýna; Veselá, Barbora; Novotná, Kateřina; Rajsner, Lukáš; Holub, Petr; Urban, Otmar

    Brno: Global Change Research Centre, The Czech Academy of Sciences, v. v. i., 2015 - (Urban, O.; Šprtová, M.; Klem, K.), s. 86-89 ISBN 978-80-87902-10-3. [Global Change: A Complex Challenge /4th/. Brno (CZ), 23.03.2015-24.03.2015] R&D Projects: GA MŠk(CZ) LO1415 Grant ostatní: AV ČR(CZ) M200871201 Institutional support: RVO:67179843 Keywords : lower canopy * Norway spruce * altitudinal gradients Subject RIV: EH - Ecology, Behaviour

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

    OpenAIRE

    Vargas Rincón Carlos Alberto; Vargas Ríos Orlando

    2006-01-01

    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 vu...

  6. 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

  7. 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

  8. Loss measurement programs at TRIUMF

    International Nuclear Information System (INIS)

    During the KAON Factory Project Definition Study year we plan to directly measure magnet losses at sinusoidal excitation and at the proposed dual frequency excitation of the booster and driver rings. The losses due to transverse fields in the conductors will be measured using the NINA magnets and core losses will be measured on steel samples using an Epstein Bridge method which allows dc bias levels to be applied. The proposed tests are described and some preliminary findings are presented. The aim of these tests is to allow us to understand the loss processes and to allow us to calculate these losses with greater accuracy and confidence

  9. 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.

  10. 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.

  11. 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

  12. Weight loss is effective for symptomatic relief in obese subjects with knee osteoarthritis independently of joint damage severity assessed by high-field MRI and radiography

    DEFF Research Database (Denmark)

    Gudbergsen, H; Boesen, M; Lohmander, L S; Christensen, R; Henriksen, M; Bartels, E M; Christensen, Pia; Rindel, L; Aaboe, J; Danneskiold-Samsøe, B; Riecke, B F; Bliddal, H

    2012-01-01

    With an increasing prevalence of older and obese citizens, the problems of knee osteoarthritis (KOA) will escalate. Weight loss is recommended for obese KOA patients and in a majority of cases this leads to symptomatic relief. We hypothesized that pre-treatment structural status of the knee joint...

  13. 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. PMID:26908366

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

    Science.gov (United States)

    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 populations. Lippia origanoides was sampled along an altitudinal gradient from 365 to 2595 m.a.s.l. throughout Chicamocha River Canyon, a semiarid area in northeastern Colombia. Genetic diversity was assessed by means of AFLP markers. The number of AFLP loci (355) and the number of individuals sampled (173) were sufficient to reliably identify four populations at contrasting altitudes (FST = 0.18, P-value < 0.0000), two populations in the lower basin, one population in the medium basin, and one population in the upper basin, with a low level of admixture between them. In average, genetic diversity within populations was relatively high (Ht = 0.32; I = 0.48); nevertheless, diversity was significantly reduced at higher altitude, a pattern that may be consistent with a scenario of range expansion toward higher elevations in an environment with more extreme conditions. The differences in altitude among the basins in the Chicamocha River seem to be relevant in determining the genetic structure of this species. PMID:23170204

  15. 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

  16. Abundance of Royle’s pika (Ochotona roylei along an altitudinal gradient in Uttarakhand, Western Himalaya

    Directory of Open Access Journals (Sweden)

    Sabuj Bhattacharyya

    2010-06-01

    Full Text Available Abstract The relative abundance of Royle’s pika (Ochotona roylei was studied in a part of the Kedarnath Wildlife Sanctuary, Uttarakhand, West Himalaya along an altitudinal gradient from 2900 to 3650 m a.s.l. Pikas’ detection probability and relative abundance per month and habitat were recorded by monthly surveys consisting of three sampling sessions of four hours each. Food plant species were identified by visual observation and quantified by a standard quadrat method. The highest relative abundance was observed at man-made walls and surroundings in the alpine zone and on broken slopes in the sub-alpine one, whereas alpine meadows showed the lowest abundance. A total of 26 plant species were found to be consumed by pikas. The proportion of forage plants was the highest (77.4% on the rocky slopes of the timberline zone The results of multiple regressions suggest that rock cover is the main factor affecting the relative abundance of Royle’s pika. Rocky areas probably offer both nest-sites and temporary refuges to escape from predators.
    Riassunto Abbondanza relativa del pica di Royle (Ochotona roylei lungo un gradiente altitudinale in Uttarakhand, Himalaya occidentale. In un’area del Kedarnath Wildlife Sanctuary (Uttarakhand, Himalaya occidentale, é stata stimata l’abbondanza relativa del pika di Royle (Ochotona roylei lungo un gradiente altitudinale compreso tra 2900 e 3650 m. Sono stati identificate tre fasce altitudinali e 10 habitat complessivi. La probabilità di osservazione e l’abbondanza relativa dei pika per ciascun mese e habitat sono state stimate tramite censimenti mensili consistenti in tre periodi di 4 ore ciascuno. Le specie vegetali consumate sono state identificate tramite osservazione diretta; la disponibilità è stata quantificata tramite rilievo fitosociologico standard. L’abbondanza relativa maggiore è stata riscontrata nella

  17. 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

  18. 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.

  19. 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

  20. Sinopsis sobre la riqueza y la distribución geográfica y altitudinal de las Orquídeas de Colombia

    OpenAIRE

    Betancur Julio César; Sarmiento Téllez Jorge

    2006-01-01

    El estudio analiza la riqueza, distribución geográfica y altitudinal de la familia Orchidaceae, que presenta en Colombia,
    3.695 especies y 251 géneros. La región andina concentra el 87,2%, 1.745 especies. Se han encontrado 1.544 especies endémicas para Colombia. La mayor concentración se localiza entre 0 y 200 m y entre 1.801 y 2.000 m. De origen andino, se encontraron 1.259 especies; 298; de amplia distribución en el neotrópico; 250 especies son de origen centroamericano; 111 espe...

  1. Diversity and species turnover on an altitudinal gradient in Western Cape, South Africa: baseline data for monitoring range shifts in response to climate change

    Directory of Open Access Journals (Sweden)

    L. Agenbag

    2008-12-01

    Full Text Available A temperature and moisture gradient on the equator-facing slope of Jonaskop on the Riviersonderend Mountain. Westem Cape has been selected as an important gradient for monitoring the effects of climate change on fynbos and the Fynbos- Succulent Karoo ecotone. This study provides a description of plant diversity patterns, growth form composition and species turnover across the gradient and the results of four years of climate monitoring at selected points along the altitudinal gradient.The aim o f this study is to provide data for a focused monitoring strategy for the early detection of climate change-related shifts in species’ ranges, as well as gaining a better understanding of the role of climate variability in shaping species growth responses, their distributions, and other ecosystem processes.

  2. 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.

  3. 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

  4. 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

  5. Derivation of a new continuous adjustment function for correcting wind-induced loss of solid precipitation: results of a Norwegian field study

    Science.gov (United States)

    Wolff, M. A.; Isaksen, K.; Petersen-Øverleir, A.; Ødemark, K.; Reitan, T.; Brækkan, R.

    2015-02-01

    Precipitation measurements exhibit large cold-season biases due to under-catch in windy conditions. These uncertainties affect water balance calculations, snowpack monitoring and calibration of remote sensing algorithms and land surface models. More accurate data would improve the ability to predict future changes in water resources and mountain hazards in snow-dominated regions. In 2010, a comprehensive test site for precipitation measurements was established on a mountain plateau in southern Norway. Automatic precipitation gauge data are compared with data from a precipitation gauge in a Double Fence Intercomparison Reference (DFIR) wind shield construction which serves as the reference. A large number of other sensors are provided supporting data for relevant meteorological parameters. In this paper, data from three winters are used to study and determine the wind-induced under-catch of solid precipitation. Qualitative analyses and Bayesian statistics are used to evaluate and objectively choose the model that best describes the data. A continuous adjustment function and its uncertainty are derived for measurements of all types of winter precipitation (from rain to dry snow). A regression analysis does not reveal any significant misspecifications for the adjustment function, but shows that the chosen model does not describe the regression noise optimally. The adjustment function is operationally usable because it is based only on data available at standard automatic weather stations. The results show a non-linear relationship between under-catch and wind speed during winter precipitation events and there is a clear temperature dependency, mainly reflecting the precipitation type. The results allow, for the first time, derivation of an adjustment function based on measurements above 7 m s-1. This extended validity of the adjustment function shows a stabilization of the wind-induced precipitation loss for higher wind speeds.

  6. 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 ...

  7. 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)

  8. Significant reduction in volume, stored energy and magnetization loss of high-field magnet coil based on the improvement of critical current characteristics in GdBCO coated conductor

    International Nuclear Information System (INIS)

    We have characterized current transport properties in a GdBa2Cu3O7-δ coated conductor fabricated by a combination of ion-beam assisted deposition (IBAD) method and pulsed laser deposition (PLD) method with reel-to-reel systems, and have applied them to a coil design for a high-field magnet. The J-E characteristics in the conductor are given as a function of temperature, magnetic field and the field angle based on percolation transition model, and its potential as a high-field magnet coil is discussed based on a finite element method analysis. As a result, we have found that the conductor with Ic = 350 A/cm-w at 77 K and self-field has a possibility to realize a 40 T magnet coil with very compact size (300 mm in outside diameter) and small usage of the coated conductor (8 km). Furthermore, we have also investigated the relationship between the scale of the magnet coil and the corresponding requirements for the conductor. Consequently, it has been suggested that the improvement of critical current characteristics of the conductor greatly advances the downsizing of the coil without large increment in hoop tensile force. In addition, it has also been found that such downsizing of the coil contributes to the reduction in stored energy and total magnetization loss of the coil. This means that the recent improvement of critical current characteristics in coated conductors is especially worthwhile for high-field magnet coils in terms not only of downsizing but also of quench protection and magnetizing/demagnetizing operation.

  9. Iron loss analysis in linear dc motor

    Energy Technology Data Exchange (ETDEWEB)

    Hippner, M.; Yamada, H.; Mizuno, T.

    1999-09-01

    The paper presents analysis of iron loss in a linear dc motor with a solid iron core. The analysis is based on a finite element magnetic field solution. The influence of magnetic bias on the iron loss is discussed. The results of the iron loss calculations are verified experimentally.

  10. 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.

  11. 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

  12. Measuring power losses due to eddy current

    International Nuclear Information System (INIS)

    Power losses in uniform cylindrical conducting articles are determined in wide range of variation of variable magnetic field induction. Relations, connecting total and specific losses with magnetic field intensity, frequency and electromagnetic and geometrical parameters of the article, are obtained. It is shown that electromagnetic transducer can be used for simultaneous determination of differential magnetic permeability and specific electric conductivity of the article, as well as for evaluation of their contribution into power losses. 8 refs., 2 figs., 2 tabs

  13. Novo registro altitudinal de Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae no Brasil - DOI: 10.4025/actascibiolsci.v31i3.785 New altitudinal record of Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae in Brazil - DOI: 10.4025/actascibiolsci.v31i3.785

    Directory of Open Access Journals (Sweden)

    Bernadete Maria Sousa

    2009-07-01

    Full Text Available Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae é uma espécie de caranguejo que habita rios e riachos montanhosos em altitudes até aproximadamente 500 m. Sua distribuição ocorre na América do Sul, desde as bacias costeiras da faixa leste do Brasil até a bacia do alto Paraná e na Argentina. O objetivo do presente trabalho foi registrar a ocorrência de T. fluviatilis em uma Unidade de Conservação de Juiz de Fora, Minas Gerais, e fornecer um novo registro altitudinal dessa espécie no Brasil. As amostras foram obtidas de outubro de 2004 a julho de 2005. Foram coletados três indivíduos vivos, dois machos e uma fêmea da espécie. Também foram analisados 16 regurgitos estomacais do cágado Hydromedusa maximiliani, dos quais, em seis foram encontrados partes corporais deste crustáceo. Muitas espécies de caranguejos do Brasil da família Trichodactylidae vivem em regiões acima de 500m do nível do mar. No presente estudo, T. fluviatilis foi coletado a 770 m de altitude, ampliando assim a faixa de distribuição altitudinal dessa espécie no Brasil. Até o presente estudo não existiam relatos de T. fluviatilis no município de Juiz de Fora, portanto este estudo também se constitui em um novo registro desse tricodatilídeo em Minas Gerais.Trichodactylus fluviatilis (Latreille, 1828 (Decapoda, Trichodactylidae is a crab species that lives in mountainous rivers and streams at altitudes up to 500m. Its distribution ranges from South America from the Basins of eastern coast of Brazil to basins of the Upper Paraná River and Argentina. The main objective of this study was to register a new occurrence of T. fluviatilis at a Conservation Unit in Juiz de Fora, Minas Gerais and provide a new altitudinal record for this species in Brazil. The samples were taken between October 2004 and July 2005. We collected three live T. fluviatilis individuals – two males and one female. We also analyzed the stomach contents of 16

  14. 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 ...

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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 ...

  1. Hair loss in women.

    Science.gov (United States)

    Harfmann, Katya L; Bechtel, Mark A

    2015-03-01

    Hair loss is a common cause of morbidity for many women. As a key member of the woman's health care team, the obstetrician/gynecologist may be the first person to evaluate the complaint of hair loss. Common types of nonscarring hair loss, including female pattern hair loss and telogen effluvium, may be diagnosed and managed by the obstetrician/gynecologist. A systematic approach to diagnosis and management of these common forms of hair loss is presented. PMID:25517757

  2. 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

  3. 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.

  4. 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.)

  5. 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

  6. 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

  7. Risk factors for the presence of chikungunya and dengue vectors (Aedes aegypti and Aedes albopictus, their altitudinal distribution and climatic determinants of their abundance in central Nepal.

    Directory of Open Access Journals (Sweden)

    Meghnath Dhimal

    2015-03-01

    Full Text Available BACKGROUND: The presence of the recently introduced primary dengue virus vector mosquito Aedes aegypti in Nepal, in association with the likely indigenous secondary vector Aedes albopictus, raises public health concerns. Chikungunya fever cases have also been reported in Nepal, and the virus causing this disease is also transmitted by these mosquito species. Here we report the results of a study on the risk factors for the presence of chikungunya and dengue virus vectors, their elevational ceiling of distribution, and climatic determinants of their abundance in central Nepal. METHODOLOGY/PRINCIPAL FINDINGS: We collected immature stages of mosquitoes during six monthly cross-sectional surveys covering six administrative districts along an altitudinal transect in central Nepal that extended from Birgunj (80 m above sea level [asl] to Dhunche (highest altitude sampled: 2,100 m asl. The dengue vectors Ae. aegypti and Ae. albopictus were commonly found up to 1,350 m asl in Kathmandu valley and were present but rarely found from 1,750 to 2,100 m asl in Dhunche. The lymphatic filariasis vector Culex quinquefasciatus was commonly found throughout the study transect. Physiographic region, month of collection, collection station and container type were significant predictors of the occurrence and co-occurrence of Ae. aegypti and Ae. albopictus. The climatic variables rainfall, temperature, and relative humidity were significant predictors of chikungunya and dengue virus vectors abundance. CONCLUSIONS/SIGNIFICANCE: We conclude that chikungunya and dengue virus vectors have already established their populations up to the High Mountain region of Nepal and that this may be attributed to the environmental and climate change that has been observed over the decades in Nepal. The rapid expansion of the distribution of these important disease vectors in the High Mountain region, previously considered to be non-endemic for dengue and chikungunya fever, calls for

  8. 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

  9. 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

  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. 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 ...

  12. 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. ...

  13. 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 ...

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. Os componentes epifítico vascular e herbáceo terrícola da Floresta Ombrófila densa ao longo de um gradiente altitudinal na Serra da Prata, Paraná

    OpenAIRE

    Blum, Christopher Thomas

    2013-01-01

    This study aimed to characterize the floristics, structure and spatial distribution of vascular epiphytes and ground herbs along an altitudinal gradient of the Atlantic Rainforest in the Serra da Prata mountain range (48 ‹41'59.39"W, 25 ‹36'46.39"S), Parana State, and to explore the existence of relationships among these elements and the environmental variation along the gradient. The study area has 6.3 hectares between 400 and 1,100 m a.s.l. The epiphytic component was quantified using 120 p...

  18. 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.

  19. AC loss in superconducting tapes and cables

    Science.gov (United States)

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  20. 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.

  1. 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.

  2. 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.

  3. 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. PMID:27112687

  4. 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

  5. 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…

  6. Understanding Rural Population Loss.

    Science.gov (United States)

    McGranahan, David A.; Beale, Calvin L.

    2002-01-01

    A quarter of nonmetro counties lost population in the 1990s, but population loss was not related to poverty rate or low educational levels, perhaps because low-skill workers can no longer expect better wages in urban areas. Population loss was related to low population density and remoteness (which decrease access to services), lack of natural…

  7. 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

  8. 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 ...

  9. 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 cannot lose weight through diet and exercise or have serious health problems caused by obesity. There are different types of weight loss surgery. They often limit the ...

  10. Acute loss of consciousness.

    Science.gov (United States)

    Tristán, Bekinschtein; Gleichgerrcht, Ezequiel; Manes, Facundo

    2015-01-01

    Acute loss of consciousness poses a fascinating scenario for theoretical and clinical research. This chapter introduces a simple yet powerful framework to investigate altered states of consciousness. We then explore the different disorders of consciousness that result from acute brain injury, and techniques used in the acute phase to predict clinical outcome in different patient populations in light of models of acute loss of consciousness. We further delve into post-traumatic amnesia as a model for predicting cognitive sequels following acute loss of consciousness. We approach the study of acute loss of consciousness from a theoretical and clinical perspective to conclude that clinicians in acute care centers must incorporate new measurements and techniques besides the classic coma scales in order to assess their patients with loss of consciousness. PMID:25702218

  11. 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

    In a mass balance of N-15-labelled nitrate added to soil grown with pea or barley, denitrification estimates using the acetylene-inhibition technique were compared with unaccounted for N-15. During the growth season of 1989, which was drier than average, N losses due to denitrification estimated 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....

  12. AC losses in filamentary YBCO/hastelloy

    International Nuclear Information System (INIS)

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  13. 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 ...

  14. 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- ...

  15. Weight loss - unintentional

    Science.gov (United States)

    ... of laxatives Other causes such as: Eating disorders, anorexia nervosa that have not been diagnosed yet Diabetes that ... do not know the reason. You have other symptoms along with the weight loss.

  16. 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 ...

  17. Nickel hydrogen capacity loss

    Science.gov (United States)

    Goualard, Jacques; Paugam, D.; Borthomieu, Y.

    1993-01-01

    The results of tests to assess capacity loss in nickel hydrogen cells are presented in outline form. The effects of long storage (greater than 1 month), high hydrogen pressure storage, high cobalt content, and recovery actions are addressed.

  18. 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

  19. 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. ...

  20. Occupational hearing loss

    Science.gov (United States)

    ... music can cause hearing loss. Sounds above 80 decibels (dB, a measurement of the loudness or strength ... is allowed. Both the length of exposure and decibel level are considered. If the sound is at ...

  1. 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.

  2. 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...

  3. Comparing energy loss phenomenology

    OpenAIRE

    van Leeuwen, M.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands)

    2009-01-01

    High-pT particle production is suppressed in heavy ion collisions due to parton energy loss in dense QCD matter. Here we present a systematic comparison of two different theoretical approximations to parton energy loss calculations: the opacity expansion and the multiple-soft scattering approximation for the simple case of a quark traversing a homogeneous piece of matter with fixed length (the TECHQM 'brick problem'), with focus on the range of parameters that is relevant for interpreting RHI...

  4. Sleep Loss and Inflammation

    OpenAIRE

    Mullington, Janet M.; Simpson, Norah S.; Meier-Ewert, Hans K.; Haack, Monika

    2010-01-01

    Controlled, experimental studies on the effects of acute sleep loss in humans have shown that mediators of inflammation are altered by sleep loss. Elevations in these mediators have been found to occur in healthy, rigorously screened individuals undergoing experimental vigils of more than 24 hours, and have also been seen in response to various durations of sleep restricted to between 25 and 50% of a normal 8 hour sleep amount. While these altered profiles represent small changes, such sub-cl...

  5. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    İdil Ünal

    2014-06-01

    Full Text Available Female androgenetic alopecia is the commonest cause of hair loss in women. It is characterized by a diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline and a characteristic pattern distribution in genetically predisposed women. Because of the uncertain relationship with the androgens Female Pattern Hair Loss (FPHL is the most preferred definition of the condition. This review has been focused on the clinical features, diagnosis and treatment alternatives of FPHL.

  6. Female pattern hair loss

    OpenAIRE

    İdil Ünal

    2014-01-01

    Female androgenetic alopecia is the commonest cause of hair loss in women. It is characterized by a diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline and a characteristic pattern distribution in genetically predisposed women. Because of the uncertain relationship with the androgens Female Pattern Hair Loss (FPHL) is the most preferred definition of the condition. This review has been focused on the clinical features, diagnosis and treatm...

  7. Female pattern hair loss

    OpenAIRE

    Archana Singal; Sidharth Sonthalia; Prashant Verma

    2013-01-01

    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...

  8. 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)...

  9. 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)

  10. 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.

  11. 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

  12. 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...

  13. Mass loss from stars

    International Nuclear Information System (INIS)

    This article discusses the different mass-loss processes of stars and how mass-loss rates determine the fate of stars in advanced stages of stellar evolution. Main sequence stars have their atmospheric structure dominated by radiation pressure. The pressure exerted by energetic photons is sufficient to drive gases off into space. This process can impact enormous turbulence to the local interstellar medium. Evolutionary effects keep these stars from fully evaporating, but the very course of their evolution is determined by this mass shedding process. Lower main sequence stars, like the sun, have a turbulent atmosphere enveloped in hot, thin coronal gas, blowing off a light stellar breeze. As the main sequence star evolves to a giant, its corona dissipates and the breeze turns into a strong stellar wind. Intermitten sputters combined with pulsational instabilities can lead to partial ejection of the atmosphere and envelope of a red giant, i.e. a planetary nebula results. The mass-loss from stars through planetary nebule combined with other mass-loss processes such as stellar winds returns a substantial amount of material to the interstellar environment. Mass-loss in binary systems is also discussed

  14. 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 ...

  15. Congenital sensorineural hearing loss

    International Nuclear Information System (INIS)

    The ears of 47 selected patients with congenital sensorineural hearing loss were examined with complex-motion tomography. The patients were divided into 3 general categories: those with a recognized syndrome, those with sensorineural hearing loss unrelated to any known syndrome, and those with microtia. A great variety of inner ear anomalies was detected, but rarely were these characteristic of a particular clinical entity. The most common finding was the Mondini malformation or one of its variants. Isolated dysplasia of the internal auditory canal or the vestibular aqueduct may be responsible for sensorineural hearing loss in some patients. Patients with microtia may also have severe inner ear abnormalities despite the fact that the outer and inner ears develop embryologically from completely separate systems

  16. 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.

  17. 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.)

  18. 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 ...

  19. 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 ...

  20. 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…

  1. 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.

  2. 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...

  3. Independents' group posts loss

    International Nuclear Information System (INIS)

    Low oil gas prices and special charges caused the group of 50 U.S. independent producers Oil and Gas Journal tracks to post a combined loss in first half 1992. The group logged a net loss of $53 million in the first half compared with net earnings of $354 million in first half 1991, when higher oil prices during the Persian Gulf crisis buoyed earnings in spite of crude oil and natural gas production declines. The combined loss in the first half follows a 45% drop in the group's earnings in 1991 and compares with the OGJ group of integrated oil companies whose first half 1992 income fell 47% from the prior year. Special charges, generally related to asset writedowns, accounted for most of the almost $560 million in losses posted by about the third of the group. Nerco Oil and Gas Inc., Vancouver, Wash., alone accounted for almost half that total with charges related to an asset writedown of $238 million in the first quarter. Despite the poor first half performance, the outlook is bright for sharply improved group earnings in the second half, assuming reasonably healthy oil and gas prices and increased production resulting from acquisitions and in response to those prices

  4. Muscle function loss

    Science.gov (United States)

    ... nerve injury, or brain damage ( stroke or other brain injury) The loss of muscle function after these types of events can be severe. Often it will not completely return, even with treatment. Paralysis can be temporary or permanent. It can affect ...

  5. Soluble calcium amendments: reducing pathogen losses

    Science.gov (United States)

    Flue gas desulfurization (FGD) gypsum is a byproduct of coal-fired power plants. Its application to agricultural fields may increase water infiltration, reduce soil erosion, and decrease nutrient losses from applications of animal manures. It may also reduce fecal bacterial contamination of surface ...

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. Muscle Loss in Elderly

    OpenAIRE

    Nikolić, Marina; Šoić Vranić, Tamara; Arbanas, Juraj; Cvijanović, Olga; Bajek, Snježana

    2010-01-01

    Aging is associated with loss of skeletal muscle mass, strength and endurance. The aim of this study was to determinate age related changes in human muscles with different function and location in the body (vastus lateralis muscle and intercostal internus muscle). Our results suggest that age related muscle atrophy affect both human skeletal muscles. Also, the results showed the increase in percentage of muscle fibers with high oxidative activity during aging.

  11. 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 ...

  12. Optical loss by surface transfer doping in silicon waveguides

    CERN Document Server

    Alloatti, Luca; Leuthold, Juerg

    2015-01-01

    We show that undoped silicon waveguides may suffer of up to 1.8 dB/cm free-carrier absorption caused by improper surface passivation. To verify the effects of free-carriers we apply a gate field to the waveguides. Smallest losses correspond to higher electrical sheet resistances and are generally obtained with non-zero gate fields. The presence of free carriers for zero gate field is attributed to surface transfer doping. These results open new perspectives for minimizing propagation losses in silicon waveguides and for obtaining low-loss and highly conductive silicon films without applying a gate voltage.

  13. Alpha-particle losses in compact torsatron reactors

    International Nuclear Information System (INIS)

    Loss of alpha particles in compact torsatron reactors is studied. For 6, 9, and 12 field period reactors, the direct loss is a relatively weak function of radius and energy and varies from ≅33% for M = 6 to ≅18% for M = 12. Loss of alpha particles through scattering into the loss region is calculated using the Fokker-Plank equation for fast ions and found to contribute an additional alpha-particle energy loss of ≅15%. The consequences of these relatively large losses for torsatron reactor design are discussed. The relationship between the direct particle losses and the magnetic field structure is also studied. Orbit losses from a variety of stellarator configurations are calculated and a figure-of-merit that characterizes the orbit confinement of a magnetic configuration is deduced from these calculations. This figure-of-merit is used to show how the direct losses might be reduced at low aspect-ratio. Effects of finite beta on the direct particle losses are also addressed, and are shown to significantly increase the direct losses in some configurations. 15 refs., 8 figs

  14. Rotation and particle loss in Tore Supra

    International Nuclear Information System (INIS)

    Although plasma heating with ICRF imparts negligible angular momentum to a tokamak plasma, the high energy particles give significant torque to the plasma through diamagnetic effects. This effect has been directly modeled through guiding center simulations. It is found that heating in Tore Supra, with the location of the resonance surface on the high field side of the magnetic axis, can produce negative central rotation of up to 40 km/sec. Particle loss also contributes to negative rotation, but this is not the dominant effect in most discharges. In this work the authors examine the effect of collisions and strong plasma rotation on the loss of high energy particles

  15. 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

  16. 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.

  17. 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...

  18. [Progressive hearing loss].

    Science.gov (United States)

    Reiss, M; Reiss, G

    2000-01-01

    Progressive sensorineural hearing loss (SNHL) is defined as hearing loss of unknown etiology with fairly high-speed progression. Its diagnostic criteria consist of the following: that it is 1) progressive, 2) with bilateral involvement, and 3) of unknown etiology. Due to recent advances in diagnostics, imaging and management, SNHL has gained much interest from otologists in the last few years. They provide new insight into the physiology and pathophysiology of hearing. SNHL which is sudden in onset, fluctuating, and/or progressive complicates medical management, hearing aid selection, and individualized educational planning for a hearing-impaired patient. Existing hypotheses on the etiology of SNHL are judged on experimental, clinical, laboratory and radiological evidence. Cardiovascular and rheologic diseases, hereditary disorders, immunological phenomena, infections, environmental causes like noise, ototoxic drugs and industrial substances and systemic maladies must be included in the diagnostic reflections. Potential concepts of treatment include rheologic medications and corticosteroids. Hearing aids and timely cochlear implant operation are further possible forms of treatment. PMID:10893764

  19. 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...

  20. 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...

  1. 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.

  2. Numerical estimation of AC loss in superconductors with ripple current

    International Nuclear Information System (INIS)

    Highlights: •The loss energy density with ripple current is numerically calculated. •Irie–Yamafuji model is used for magnetic field dependence of critical current. •Calculated result of cylindrical superconductor agrees with theoretical result. •AC loss of strip superconductor becomes large at small ripple current amplitude. •Strip superconductor should be used as a form of hollow cylinder to reduce AC loss. -- Abstract: The loss energy density (AC loss) with ripple current is numerically calculated by finite element method for cylindrical and strip superconductors based on Irie–Yamafuji model in which the magnetic field dependence of the critical current density is taken into account for design of DC transmission cable system. It is confirmed that calculated result of the AC loss in the cylindrical superconductor with the ripple current agrees well with theoretical estimation which was reported in the previous work. On the contrary, the AC loss in the strip superconductor with the ripple current is obtained only by numerical calculation. It is found that the AC loss in the strip superconductor of the ripple current becomes larger than that without DC current at small ripple current amplitude, since the penetration depth of magnetic field becomes large. Therefore, it is recommended that strip superconductor is better to use as cylindrical hollow superconductor for DC transmission cable system to reduce the AC loss

  3. Linear-optics manipulations of photon-loss codes

    OpenAIRE

    Banaszek, Konrad; Wasilewski, Wojciech

    2007-01-01

    We discuss codes for protecting logical qubits carried by optical fields from the effects of amplitude damping, i.e. linear photon loss. We demonstrate that the correctability condition for one-photon loss imposes limitations on the range of manipulations than can be implemented with passive linear-optics networks.

  4. 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.

  5. 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.

  6. Reducing the losses of optical metamaterials

    International Nuclear Information System (INIS)

    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, (varepsilon). 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.

  7. 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 ...

  8. 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 ...

  9. 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...

  10. 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?

  11. 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.

  12. 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...

  13. 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.

  14. 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 ...

  15. 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...

  16. 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.)

  17. 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,

  18. 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

  19. Mobile phone induced sensorineural hearing loss

    International Nuclear Information System (INIS)

    The increased use of mobile phones worldwide has focused interest on the biological effects and possible health outcomes of exposure to radiofrequency fields from mobile phones, and their base stations. Various reports suggest that mobile phone use can cause health problems like fatigue, headache, dizziness, tension and sleep disturbances, however, only limited research data is available in medical literature regarding interaction between electromagnetic fields emitted by mobile phones and auditory function and the possible impact on hearing. We report a case of sensorineural hearing loss due to Global System for Mobile Communication mobile phone use in a 42-year-old male. (author)

  20. 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.

  1. 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

  2. Minimizing Digital Data Loss.

    Science.gov (United States)

    Chande, Milan

    2015-10-01

    Clinical photography has now reached all areas of dentistry, with camera equipment and photography skills being present in many practices. Whilst taking good photographs is just one part of improving record-keeping, the other part, which is arguably the more, important aspect, is to store securely this vast amount of data that is created. This article intends to explore the options available to practices to store the data securely and recommends the easiest and most effective ways available today. CPD/Clinical Relevance: With clinical photographs becoming ever more important in the field of dentistry, correct storage and use of camera equipment is important. PMID:26685474

  3. [Steroid-responsive sensorineural hearing loss with low tone loss].

    Science.gov (United States)

    Toriya, R; Yamashita, H; Hisashi, K; Komune, S; Komiyama, S

    1995-11-01

    Five cases of sensorineural hearing loss of sudden onset were reviewed. They were not responsive to administration of ATP and Vit. B12, but very responsive to steroid administration. All the patients were male and showed hearing loss in low frequencies in pure tone audiogram. Administration of steroid recovered hearing impairment immediately. However, cessation of steroid aggravated the recovered hearing. Serological and immunological examinations did not show any abnormal findings on all the patients. It was considered that these five patients had characteristics of both steroid-sensitive and low tone-loss type sensorineural hearing losses. PMID:8566929

  4. 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

  5. Optimization of fuel cycles: marginal loss values

    International Nuclear Information System (INIS)

    Uranium processing from the pit to the fuel element rod entails metal losses at every step. These losses become more and more expensive with the elaboration of the metal. Some of the uranium must be accepted as definitely lost whilst the rest could be recovered and recycled. The high cost of these losses, whether they are recycled or not, and the fact that the higher the enrichment is the higher their costs are, make it necessary to take them into account when optimizing fuel cycles. It is therefore felt important to determine their most desirable level from an economic point of view at the various nuclear fuel processing stages. However, in France as in some other countries, fissile material production is a state concern, whilst fuel element fabrication is carried out by private enterprise. Optimization criteria and the economic value of losses are therefore different for each of the two links in the fabrication chain. One can try in spite of this to reach an optimum which would conform to public interest, without interfering with the firm's sales policy. This entails using the fact that for a given output marginal costs are equal at the optimum. One can therefore adjust the level of the losses to attain this equation of marginal costs, as these are easier to obtain from the firm than a justification of the actual prices. One notices moreover that, although mainly concerned with losses, this global analysis can bring both the state and the firm to a better use of other production factors. An account is given of the theory of this economic optimization method and practical applications in the field of natural uranium-graphite moderated and CO2 cooled reactor fuel element fabrication are offered. (authors)

  6. 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.

  7. 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.

  8. Occupational Hearing Loss in Korea

    OpenAIRE

    Kim, Kyoo Sang

    2010-01-01

    In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases ...

  9. Hearing Loss: Diagnosis and Evaluation.

    Science.gov (United States)

    Zazove, Philip; Atcherson, Samuel R; Moreland, Christopher; McKee, Michael M

    2015-07-01

    Hearing loss is a common disability in the United States, most frequent among men, elderly individuals, and veterans but is increasingly affecting other younger adults. Types of hearing loss include sensorineural, conductive, and mixed. Hearing loss in children often is related to infections, time spent in a neonatal intensive care unit, and genetic etiologies. Presbycusis (ie, age-related hearing loss) is the most common etiology in adults. Adverse effects of untreated hearing loss include isolation, depression, lower income, and higher unemployment. Hearing aid use reduces levels of disability, cognitive impairment, and psychosocial distress while improving quality of life. At least 75% of individuals with hearing loss are not receiving treatment for it. All infants should be screened for hearing loss, as should children and adults with risk factors. The Joint Commission on Infant Hearing Screening has a 1-3-6 goal for screening: identification by age 1 month, confirmation by age 3 months, and intervention by age 6 months. The presence of an ongoing physician-patient relationship increases the likelihood that a patient will admit to having a hearing loss. Adults can be screened using single-question or standardized instrument screens. All patients with suspected hearing loss should undergo audiometry by an audiology subspecialist. PMID:26161523

  10. 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...

  11. 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.

  12. 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

  13. 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.

  14. Theoretical analysis of ac losses in high temperature superconducting bulks

    International Nuclear Information System (INIS)

    Ac loss behavior in HTS bulk materials is studied by developing an analytic method. The self-heating effect on the distributions of temperature in HTS bulks has been calculated. A critical frequency which sets the upper limit for driving frequency of the external field in sustaining a superconducting state is obtained. Our model provides useful information of understanding the experimental phenomena, including an anomalous ac loss behavior, a retardation of the inner field respect to the external ac field, etc., in HTS bulk materials

  15. 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.

  16. 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.)

  17. 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…

  18. Interface losses in multimaterial resonators

    DEFF Research Database (Denmark)

    Villanueva, L.G.; Amato, B.; Larsen, Tom;

    2014-01-01

    vibrational modes to achieve a total of more than 3000 experimental points that allow us to quantify the contribution of surface and volume intrinsic (material related) losses in MEMS resonators. We conclude that the losses in the interface between silicon nitride and aluminum is a very important contributor...

  19. 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.

  20. World offshore energy loss statistics

    International Nuclear Information System (INIS)

    Offshore operations present a unique set of environmental conditions and adverse exposure not observed in a land environment taking place in a confined space in a hostile environment under the constant danger of catastrophe and loss. It is possible to engineer some risks to a very low threshold of probability, but losses and unforeseen events can never be entirely eliminated because of cost considerations, the human factor, and environmental uncertainty. Risk events occur infrequently but have the potential of generating large losses, as evident by the 2005 hurricane season in the Gulf of Mexico, which was the most destructive and costliest natural disaster in the history of offshore production. The purpose of this paper is to provide a statistical assessment of energy losses in offshore basins using the Willis Energy Loss database. A description of the loss categories and causes of property damage are provided, followed by a statistical assessment of damage and loss broken out by region, cause, and loss category for the time horizon 1970-2004. The impact of the 2004-2005 hurricane season in the Gulf of Mexico is summarized

  1. Scannerless laser range imaging using loss modulation

    Energy Technology Data Exchange (ETDEWEB)

    Sandusky, John V. (Albuquerque, NM)

    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.

  2. Bilateral Pial siderosis and hearing loss

    International Nuclear Information System (INIS)

    Seven adult patients with bilateral progressive hearing loss (six male, one female; aged 40-74 years) were studied with a high-field strength (1.5-T) magnetic resonance (MR) system after previous negative workup with either air contrast or intravenous contrast medium-enhanced computed tomography (CT). In all instances, the patients showed extensive evidence of pial siderosis outlining the posterior fossa subarachnoid space. The siderosis was manifested (on long repetition time images) as an increasing susceptibility effect (hypointensity) with a prolongation of echo time. The results of this study indicate that a negative CT examination is inadequate in patients with bilateral hearing loss and that when evidence of siderosis is found on MR images, an etiology for prior subarachnoid hemorrhage must be pursued

  3. 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

  4. 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 ...

  5. 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.

  6. 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 ...

  7. Carcass and meat quality of finished and non-finished Limousin heifers from alpine livestock systems differing in altitudinal origin of the forage.

    Science.gov (United States)

    Gangnat, Isabelle D M; Kreuzer, Michael; Clavijo McCormick, Andrea; Leiber, Florian; Berard, Joel

    2016-04-01

    Effects of the alpine origin of the forage and of finishing on carcass and beef quality were quantified by modelling different alpine livestock system alternatives. Thirty-five Limousin heifers, initially weighing 383 ± 45 kg, were fed fresh grass at 400 or 2000 m above sea level, or a 1:1 mixture of alpine grass and lowland grass hay at 2000 m. After 9 weeks, the six heaviest and oldest animals per group were slaughtered. The remaining animals were finished for 8 weeks on a silage-concentrate diet in the lowlands to similar age and body weight as the first slaughtered group. Carcass and meat quality (M. longissimus thoracis) were assessed in various respects. The average daily gains achieved were of about 600 g/d and similar between forage-type groups. Dressing percentage was 53.5% in the alpine and 57.2% in the lowland group. Carcass conformation and fat cover scores did not differ between forage-type groups. The meat from the alpine groups had greater ultimate pH and smaller redness, yellowness and protein contents. Still, these differences were of minor practical relevance. There was no forage-type effect on water-holding capacity and shear force of the meat. The alpine systems enhanced the proportion of α-linolenic acid in intramuscular fat and decreased the levels of some volatile compounds in perirenal fat. Finishing resulted in compensatory growth, especially in the animals previously fed lowland grass. There was a trend for the finished compared with the non-finished groups towards greater carcass fat cover and intramuscular fat content. Additionally, ultimate pH was smaller and cooking loss was greater with than without finishing. Meat colour differences were also observed. Shear force was not affected by finishing. The finished animals had a smaller α-linolenic acid proportion in the intramuscular fat. In conclusion, the forage type had small effects on carcass and meat quality. Finishing did not substantially improve carcass and meat quality

  8. Transport current losses in Bi2223 high temperature superconductors

    International Nuclear Information System (INIS)

    Bi2223 high temperature superconductor (HTS) tapes are expected to be used in power industry such as fault current limiter, transformer, magnets, transmission cables. For most of applications of Bi2223 tapes, the superconductor will transport ac current and/or be exposed to applied magnetic field. AC loss is one of important parameters to evaluate the economic feasibility of HTS ceramic superconductors in those applications. Extensive investigations have been done to understand the mechanism of generation of AC loss and minimize it. In this study, AC losses in Bi2223 (HTS) tapes were measured at 77 K. The effects of different factors, such as, current distribution, heat recycling, transport current wave and applied DC magnetic field, were investigated on the AC losses in Bi2223 HTS tapes. Possible explanations were presented in the paper

  9. 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...... 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...... 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...

  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

    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...

  11. 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...

  12. 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.

  13. 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.

  14. Analytical description of AC losses for high temperature superconductors

    International Nuclear Information System (INIS)

    Full text: AC losses for high temperature superconductors have been calculated by considering the effects of the temperature distribution and the flux flow resistance. Maxwell's equations and thermal diffusion equation are used to calculate the distribution of magnetic field and the temperature inside the superconductors, respectively. The flux flow effect on the AC losses is calculated by using the extended critical state model. An analytical expression of the AC losses is obtained using a superposition approximation in which the cases of complete and incomplete magnetic field penetration have been distinguished. The expression can well explain the experimental observations of the frequency dependence of the AC losses per cycle in high temperature superconductors. It is clearly shown from the analytical expression that the effect of the thermal distribution inside the superconductors is different from the effect caused by flux flow resistance. In the case of incomplete magnetic penetration, the temperature distribution results in the increase of the AC losses per cycle upon frequency whereas the flux flow leads to the decrease of the AC losses per cycle upon frequency. In the case of complete magnetic penetration the results are opposite to those in the previous case. Due to the extremely strong flux flow in high temperature superconducting materials, the effect of the flux flow on the AC losses is dominant, and the overall dependence of AC losses per cycle upon frequency is controlled by the flux flow. On the other hand, because the inhomogeneous distribution of the temperature inside the superconductors which is normal higher in the center than near the edge, there is an upper limit for the frequency beyond which the superconductivity will be totally destroyed by AC losses. Analytical expressions for the critical frequency, distributions of magnetic field and critical current density are also obtained

  15. Supplementation with carnitine for weight loss: a biochemical approach

    Directory of Open Access Journals (Sweden)

    José Henry Osorio

    2011-11-01

    Full Text Available Carnitine is a molecule involved in transporting activated fatty acids among different cellular compartments, which is mostlikely present in all animal species, and in numerous microorganisms and plants. Recently the trend in the field of weightcontrol is to include carnitine in the diet as an agent responsible for weight loss. In the present review, some findings arediscussed from a biochemical point of view to illustrate if the use of carnitine for weight loss can be considered fiction orreality.

  16. 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.

  17. Ripple losses during ICRF heating in Tore Supra

    International Nuclear Information System (INIS)

    The toroidal field coils in Tore Supra are supra-conducting, and their number is restricted to 18. As a result, the ripple is fairly large, about 7% at the plasma boundary. Tore Supra has consequently been equipped with dedicated ripple loss diagnostics, which has allowed ripple loss studies. This paper reports on the measurements made with these diagnostics and provides an analysis of the experimental results, comparing them with theoretical expectations whenever possible. Furthermore, the main heating source accelerating ions in Tore Supra is ion cyclotron resonance range of frequency (ICRF) heating, and the paper provides new information on the ripple losses of ICRF accelerated ions. (author)

  18. 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

  19. 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: ( ...

  20. 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 ...

  1. Resounding Facts on Hearing Loss

    Science.gov (United States)

    Apfel, Robert E.

    1977-01-01

    Provides a brief description of the physiology of the human ear. The effect of sustained noise levels on hearing loss is discussed, as well as the establishment of maximum noise levels for American industries. (CP)

  2. 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 ...

  3. Older Adults and Smell Loss

    Medline Plus

    Full Text Available ... environment and it warns us of dangers, such as bad smells, it attracts us to good smells. ... all. I have no sense of smell. Narrator: A sinus infection led to her loss of smell. ...

  4. 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 ...

  5. 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)....

  6. 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.))

  7. Wetland Loss and Research Orientation

    OpenAIRE

    Sullivan, Patrick J.; Ziyan Wang; Mark Bain; Xi Chen

    2012-01-01

    The literature analysis method used in this paper outlines variations in research topics. We tested whether research on wetlands is topic-centered, comparative of different wetland classes, or aimed at wetland loss. We analyzed research papers to identify clusters of research activity and interpreted these clusters relative to wetland function and type. Furthermore, a case study on 61 papers was conducted in order to find a critical path of wetland loss induced by different causes. From this ...

  8. Distribuição altitudinal e simpatria das aves do gênero Drymophila Swainson (Passeriformes, Thamnophilidae na Mata Atlântica Elevational distribution and sympatry of birds of the genus Drymophila Swainson (Passeriformes, Thamnophilidae in the Atlantic forest

    Directory of Open Access Journals (Sweden)

    Henrique Rajão

    2006-09-01

    Full Text Available Foram descritas e analisadas as distribuições altitudinais das seis espécies de Drymophila Swainson, 1824, endêmicas da Mata Atlântica e identificados e discutidos os casos de simpatria. Para isso, foram usados dois conjuntos de dados, um em escala local (a Serra dos Órgãos, um segmento da Serra do Mar no Estado do Rio de Janeiro e outro em escala regional (Mata Atlântica. Os registros e as altitudes na Serra dos Órgãos foram obtidos diretamente no campo enquanto que os dados da Mata Atlântica foram obtidos principalmente a partir de exemplares depositados em museus de história natural. Os dois conjuntos de dados mostraram um padrão similar de distribuição altitudinal das espécies: D. squamata (Lichtenstein, 1823 e D. ferruginea (Temminck, 1822 nas menores altitudes, D. malura (Temminck, 1825, D. ochropyga (Hellmayr, 1906 e D. rubricollis (Bertoni, 1901 com limites altitudinais semelhantes entre si e intermediários em relação às demais espécies e D. genei (Filippi, 1847, restrita às maiores altitudes. A maior parte das localidades na Mata Atlântica e pontos de observação na Serra dos Órgãos apresenta apenas uma ou duas espécies. Isso sugere que, embora possam ocorrer nas mesmas áreas ou localidades, as espécies tendem a se excluir. Drymophila squamata e D. malura foram as espécies que menos vezes ocorreram em simpatria proporcionalmente, nas duas escalas de análise. A simpatria entre as espécies irmãs D. ochropyga-D. genei e D. ferruginea-D. rubricollis ocorreu em localidades nas Serras do Mar e da Mantiqueira, sempre em faixas altitudinais estreitas, nunca superiores a 300 m de intervalo.The elevational distribution of Atlantic forest Drymophila Swainson, 1824 was analyzed and sympatry cases were identified and discussed. Two data sets were used, one with local scale data (a portion of Serra do Mar called Serra dos Órgãos, in Rio de Janeiro state and other with regional scale data (Atlantic forest. The Serra

  9. 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.

  10. 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

  11. Design and AC loss analysis of a superconducting synchronous motor

    International Nuclear Information System (INIS)

    This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines

  12. Design and AC loss analysis of a superconducting synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Q [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Majoros, M [Department of Materials Science and Engineering, Ohio State University (United States); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2006-11-15

    This paper gives a conceptual design of a superconducting synchronous motor consisting of both high-temperature superconducting rotating field winding and armature winding. The AC losses of the armature winding of the motor have been investigated experimentally and numerically, by considering the self-field of the superconducting coils and the rotating magnetic field exposed on the armature winding. The recent developments of YBCO-coated conductors present the possibility of achieving a wholly superconducting machine of significantly smaller size and weight than a conventional machine. Both the rotating field winding and the armature winding are composed of YBCO high-temperature superconducting (HTS) coils. A low AC loss armature winding design has been developed for this superconducting synchronous motor. The performance of the machine was investigated by modelling with the finite-element method. The machine's torque is calculated from first principles by considering the angle between the field and the armature main flux lines.

  13. Sensorineural hearing loss following irradiation to the malignant tumor of the head and neck

    International Nuclear Information System (INIS)

    We observed sensorineural hearing loss following X-ray irradiation to the malignant tumor of head and neck. There were 24 patients whose auditory organs lied within the irradiation field. Ten of these patients were affected by sensorineural hearing loss. Hearing loss occurred at a high frequency in elderly patients, epipharynx tumor and high dose of irradiation. Many cases revealed high tone hearing loss. Most cases showed about a 20∼30 dB hearing loss, so their impediment seemed not severe in daily life. In some of these cases, we could have temporal bone findings, but there were no particular findings relevant to sensorineural hearing loss. (author)

  14. 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...

  15. AC Loss Analysis on the Superconducting Coupling Magnet in MICE

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun; Jia, LinXinag

    2008-07-08

    A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.

  16. Heat loss optimisation in CNC motors

    Directory of Open Access Journals (Sweden)

    R.A. Mahdavinejad

    2009-01-01

    Full Text Available Purpose: Heat loss plays very important role in CNC systems, especially in suspension systems with permanent load that are usually used for testing, detection and automatic cutting, the adjusting of motor torque in each axis is based on starting by maximum current required to overcome against resistant torque on the motion surface of the system.Design/methodology/approach: In this research a new control method is introduced for the minimization of heat loss in CNC motors. In these systems the misdirected current that causes magnetic misalignment and reduces the torque is converted to heat in the motor winding, thus reducing the motor continuous torque capability.Findings: This method is based on an open-architecture of a dynamic control to optimize the input current in order to dissipate the minimal heat loss. So that, it reaches the requested velocity-position condition with the lowest amount of misaligned magnetic field and current converted to heat.Research limitations/implications: The dynamic performance implications are more important than the steady-state torque disadvantage.Practical implications: An algorithm for the dynamic torque control is given and a simulation is carried out using this algorithm for a two axis CNC cutting system with two-guider bars suspension. Reaching to the actual requested motor current is practical implication. From this point of view, the enhanced free running of pulse width modulated (PWM is represented.Originality/value: Results obtained in this work show that using the proposed procedure the heat loss is minimized while the speed errors are reduced and the surface finish is improved. Finally, the results of this dynamic control method is represented on CNC two axes cutting machine and extended the results on the other systems.

  17. 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”.

  18. Loss of inventory control transient

    International Nuclear Information System (INIS)

    Scenarios resulting from the loss of inventory control in the Primary Heat Transport (PHT) system due to loss of control to feed and bleed valves are developed here. Their consequences are also discussed. The loss of inventory control resulting in net feed flow will over pressurize the PHT system. If reactor trip is not initiated at high pressure trip set point, opening of the primary relief valves at 1631 psi g will terminate the transient. If opening of primary relief valves is also not credited, PHT pressure will increase further and will ultimately be limited by the capacity of charging pumps of about 1741 psi g. At this pressure there is very little chance of system integrity failure as PHT design operating pressure is exceeded only by a small amount. Loss of inventory control resulting in the opening of feed and bleed valves will depressurize the system. System pressure will decrease until feed flow balances the bleed flow. Resulting system pressure (1158 psi g) will be higher than the saturation pressure at the maximum system temperature. However, loss of inventory control resulting in the opening of bleed valves alone will depressurize the system rapidly and bulk boiling will take place in about 10 seconds. 10 figs.; 8 tabs. (author)

  19. 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.

  20. 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