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Sample records for altitudinal field loss

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

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    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. Latitudinal and altitudinal controls of Titan's dune field morphometry

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    Le Gall, A.; Hayes, A. G.; Ewing, R.; Janssen, M. A.; Radebaugh, J.; Savage, C.; Encrenaz, P.; the Cassini Radar Team

    2012-01-01

    Dune fields dominate ˜13% of Titan's surface and represent an important sink of carbon in the methane cycle. Herein, we discuss correlations in dune morphometry with altitude and latitude. These correlations, which have important implications in terms of geological processes and climate on Titan, are investigated through the microwave electromagnetic signatures of dune fields using Cassini radar and radiometry observations. The backscatter and emissivity from Titan's dune terrains are primarily controlled by the amount of interdune area within the radar footprint and are also expected to vary with the degree of the interdunal sand cover. Using SAR-derived topography, we find that Titan's main dune fields (Shangri-La, Fensal, Belet and Aztlan) tend to occupy the lowest elevation areas in Equatorial regions occurring at mean elevations between ˜-400 and ˜0 m (relative to the geoid). In elevated dune terrains, we show a definite trend towards a smaller dune to interdune ratio and possibly a thinner sand cover in the interdune areas. A similar correlation is observed with latitude, suggesting that the quantity of windblown sand in the dune fields tends to decrease as one moves farther north. The altitudinal trend among Titan's sand seas is consistent with the idea that sediment source zones most probably occur in lowlands, which would reduce the sand supply toward elevated regions. The latitudinal preference could result from a gradual increase in dampness with latitude due to the asymmetric seasonal forcing associated with Titan's current orbital configuration unless it is indicative of a latitudinal preference in the sand source distribution or wind transport capacity.

  3. Evaluation of the impact of frost resistances on potential altitudinal limit of trees.

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    Charrier, Guillaume; Cochard, Hervé; Améglio, Thierry

    2013-09-01

    Winter physiology of woody plants is a key issue in temperate biomes. Here, we investigated different frost resistance mechanisms on 1-year-old branches of 11 European tree species from November until budburst: (i) frost hardiness of living cells (by electrolyte leakage method), (ii) winter embolism sensitivity (by percentage loss of conductivity: PLC) and (iii) phenological variation of budburst (by thermal time to budburst). These ecophysiological traits were analyzed according to the potential altitudinal limit, which is highly related to frost exposure. Seasonal frost hardiness and PLC changes are relatively different across species. Maximal PLC observed in winter (PLCMax) was the factor most closely related to potential altitudinal limit. Moreover, PLCMax was related to the mean hydraulic diameter of vessels (indicating embolism sensitivity) and to osmotic compounds (indicating ability of living cells to refill xylem conducting elements). Winter embolism formation seems to be counterbalanced by active refilling from living cells. These results enabled us to model potential altitudinal limit according to three of the physiological/anatomical parameters studied. Monitoring different frost resistance strategies brings new insights to our understanding of the altitudinal limits of trees.

  4. 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...... relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits....

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

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    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.

  6. Differences between Non-arteritic Anterior Ischemic Optic Neuropathy and Open Angle Glaucoma with Altitudinal Visual Field Defect.

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    Han, Sangyoun; Jung, Jong Jin; Kim, Ungsoo Samuel

    2015-12-01

    To investigate the differences in retinal nerve fiber layer (RNFL) change and optic nerve head parameters between non-arteritic anterior ischemic optic neuropathy (NAION) and open angle glaucoma (OAG) with altitudinal visual field defect. Seventeen NAION patients and 26 OAG patients were enrolled prospectively. The standard visual field indices (mean deviation, pattern standard deviation) were obtained from the Humphrey visual field test and differences between the two groups were analyzed. Cirrus HD-OCT parameters were used, including optic disc head analysis, average RNFL thickness, and RNFL thickness of each quadrant. The mean deviation and pattern standard deviation were not significantly different between the groups. In the affected eye, although the disc area was similar between the two groups (2.00 ± 0.32 and 1.99 ± 0.33 mm(2), p = 0.586), the rim area of the OAG group was smaller than that of the NAION group (1.26 ± 0.56 and 0.61 ± 0.15 mm(2), respectively, p field defects, optic disc head analysis of not only the affected eye, but also the unaffected eye, by using spectral domain optical coherence tomography may be helpful.

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

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

    2014-06-01

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

  8. Animal Fascioliasis: Perspectives from high altitudinal regions.

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    Lyngdoh, Damanbha; Sharma, Sunil; Roy, Bishnupada; Tandon, Veena

    2016-12-15

    The parasitic flukes of the genus Fasciola (Platyhelminthes: Trematoda: Digenea) cause fascioliasis or liver-rot disease in ruminant livestock in tropical and sub-tropical regions of the world. Classically, two species of Fasciola- F. hepatica and F. gigantica, are universally recognized as taxonomically valid species. Our survey studies on ovid and bovid animals including yak and mithun from high altitudinal mountainous regions in Northeast India revealed the occurrence of Fasciola gigantica and also Fasciola sp.- an intermediate form, at altitudes between 5000 and 14,085 feet above sea level (asl). Two morphotypes- F. hepatica - like and F. gigantica - like, of Fasciola species were reported from the high altitudinal areas of Northeast India; most of these locales constitute new-locality and first records for the occurrence of these liver flukes. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

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    Andrea X. González-Reyes

    2017-12-01

    Full Text Available This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna and two ecotones (Yungas-Monte and Prepuna of Northwestern Argentina (altitudinal range of 2,500 m, and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna. Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate in addition to a geographic gradient (the distance of decay of similarity, demonstrating that the species turnover is important to explain the beta diversity along the

  10. Strong altitudinal partitioning in the distributions of ectomycorrhizal fungi along a short (300 m) elevation gradient

    OpenAIRE

    Jarvis, Susan G.; Woodward, Steve; Taylor, Andy F.S.

    2015-01-01

    • Changes in species richness and distributions of ectomycorrhizal (ECM) fungal communities along altitudinal gradients have been attributed to changes in both host distributions and abiotic variables. However, few studies have considered altitudinal relationships of ECM fungi associated with a single host to identify the role of abiotic drivers. To address this, ECM fungal communities associated with one host were assessed along five altitudinal transects in Scotland. • Roots of Scots pin...

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

    NARCIS (Netherlands)

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

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

  12. Compositional changes in bee and wasp communities along Neotropical mountain altitudinal gradient.

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    Lucas Neves Perillo

    Full Text Available Climate conditions tend to differ along an altitudinal gradient, resulting in some species groups' patterns of lower species richness with increasing altitude. While this pattern is well understood for tropical mountains, studies investigating possible determinants of variation in beta-diversity at its different altitudes are scarce. We sampled bee and wasp communities (Hymenoptera: Aculeata along an altitudinal gradient (1,000-2,000 m.a.s.l. in a tropical mountainous region of Brazil. Trap nests and Moericke traps were established at six sampling points, with 200 m difference in altitude between each point. We obtained average climate data (1970-2000 from Worldclim v2 for altitudes at each sampling site. Nest traps captured 17 bee and wasp species from six families, and Moericke traps captured 124 morphospecies from 13 families. We found a negative correlation between altitude and species richness and abundance. Temperature, precipitation, water vapor pressure, and wind speed influenced species richness and abundance, and were correlated with altitude. β-diversity was primarily determined by species turnover as opposed to nestedness, and Aculeate community similarity was higher for more similar altitudinal ranges. Moericke traps seem to be more efficient for altitudinal surveys compared to nest traps. We found high occurrence of singleton and doubleton species at all altitudes, highlighting the need for long-term studies to efficiently assess hymenopteran diversity in these environments.

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

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    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.

  14. Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil

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    Henriques-Oliveira, Ana Lucia; Nessimian, Jorge Luiz

    2010-01-01

    Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil. A study concerning taxonomic richness and composition of the aquatic insect fauna in streams within the same catchment basin along an altitudinal gradient in Southeast Brazil, was conducted to test the hypothesis that there is a faunal discontinuity in the biocenotic composition, related to differences in altitude and latitude. In Southeastern Brazil, around latitude 22°, this ...

  15. Comparison of Threshold Saccadic Vector Optokinetic Perimetry (SVOP) and Standard Automated Perimetry (SAP) in Glaucoma. Part II: Patterns of Visual Field Loss and Acceptability.

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    McTrusty, Alice D; Cameron, Lorraine A; Perperidis, Antonios; Brash, Harry M; Tatham, Andrew J; Agarwal, Pankaj K; Murray, Ian C; Fleck, Brian W; Minns, Robert A

    2017-09-01

    We compared patterns of visual field loss detected by standard automated perimetry (SAP) to saccadic vector optokinetic perimetry (SVOP) and examined patient perceptions of each test. A cross-sectional study was done of 58 healthy subjects and 103 with glaucoma who were tested using SAP and two versions of SVOP (v1 and v2). Visual fields from both devices were categorized by masked graders as: 0, normal; 1, paracentral defect; 2, nasal step; 3, arcuate defect; 4, altitudinal; 5, biarcuate; and 6, end-stage field loss. SVOP and SAP classifications were cross-tabulated. Subjects completed a questionnaire on their opinions of each test. We analyzed 142 (v1) and 111 (v2) SVOP and SAP test pairs. SVOP v2 had a sensitivity of 97.7% and specificity of 77.9% for identifying normal versus abnormal visual fields. SAP and SVOP v2 classifications showed complete agreement in 54% of glaucoma patients, with a further 23% disagreeing by one category. On repeat testing, 86% of SVOP v2 classifications agreed with the previous test, compared to 91% of SAP classifications; 71% of subjects preferred SVOP compared to 20% who preferred SAP. Eye-tracking perimetry can be used to obtain threshold visual field sensitivity values in patients with glaucoma and produce maps of visual field defects, with patterns exhibiting close agreement to SAP. Patients preferred eye-tracking perimetry compared to SAP. This first report of threshold eye tracking perimetry shows good agreement with conventional automated perimetry and provides a benchmark for future iterations.

  16. Altitudinal patterns of plant diversity on the Jade Dragon Snow Mountain, southwestern China.

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    Xu, Xiang; Zhang, Huayong; Tian, Wang; Zeng, Xiaoqiang; Huang, Hai

    2016-01-01

    Understanding altitudinal patterns of biological diversity and their underlying mechanisms is critically important for biodiversity conservation in mountainous regions. The contribution of area to plant diversity patterns is widely acknowledged and may mask the effects of other determinant factors. In this context, it is important to examine altitudinal patterns of corrected taxon richness by eliminating the area effect. Here we adopt two methods to correct observed taxon richness: a power-law relationship between richness and area, hereafter "method 1"; and richness counted in equal-area altitudinal bands, hereafter "method 2". We compare these two methods on the Jade Dragon Snow Mountain, which is the nearest large-scale altitudinal gradient to the Equator in the Northern Hemisphere. We find that seed plant species richness, genus richness, family richness, and species richness of trees, shrubs, herbs and Groups I-III (species with elevational range size 500 m, respectively) display distinct hump-shaped patterns along the equal-elevation altitudinal gradient. The corrected taxon richness based on method 2 (TRcor2) also shows hump-shaped patterns for all plant groups, while the one based on method 1 (TRcor1) does not. As for the abiotic factors influencing the patterns, mean annual temperature, mean annual precipitation, and mid-domain effect explain a larger part of the variation in TRcor2 than in TRcor1. In conclusion, for biodiversity patterns on the Jade Dragon Snow Mountain, method 2 preserves the significant influences of abiotic factors to the greatest degree while eliminating the area effect. Our results thus reveal that although the classical method 1 has earned more attention and approval in previous research, method 2 can perform better under certain circumstances. We not only confirm the essential contribution of method 1 in community ecology, but also highlight the significant role of method 2 in eliminating the area effect, and call for more

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

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    2015-01-01

    Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD) in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group. PMID:26684616

  18. Seasonal and altitudinal variation in roe deer (Capreolus pygargus tianschanicus diet on Jeju Island, South Korea

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    Pradeep Adhikari

    2016-12-01

    Full Text Available In order to understand the feeding ecology and dietary differences of roe deer (Capreolus pygargus tianschanicus in different seasons and altitudes, this study was carried out at three altitudinal sites (Songdang 250–270 m above sea level (ASL, Aradong 330–370 m ASL, Mt. Hallasan 1100 m ASL on Jeju Island, South Korea. Altogether, 205 plants taxa of six categories of foods (forbs-climbers, graminoids, trees, shrubs, conifers, and ferns were identified using morphological and molecular analyses. The highest number of dietary plants was found in summer (93 taxa and at Aradong (124 taxa and lowest at Songdang (71 taxa and in winter (51 taxa. Food categories were significantly different among the seasons (F = 15.646, p < 0.05 and altitudinal sites (F = 3.941, p < 0.05. This study revealed that dietary selectivity of roe deer shifted with seasonal and altitudinal variations and preferred to the nutritive and low fibers food.

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

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    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. Altitudinal patterns in breeding bird species richness and density in relation to climate, habitat heterogeneity, and migration influence in a temperate montane forest (South Korea).

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    Kim, Jin-Yong; Lee, Sanghun; Shin, Man-Seok; Lee, Chang-Hoon; Seo, Changwan; Eo, Soo Hyung

    2018-01-01

    Altitudinal patterns in the population ecology of mountain bird species are useful for predicting species occurrence and behavior. Numerous hypotheses about the complex interactions among environmental factors have been proposed; however, these still remain controversial. This study aimed to identify the altitudinal patterns in breeding bird species richness or density and to test the hypotheses that climate, habitat heterogeneity (horizontal and vertical), and heterospecific attraction in a temperate forest, South Korea. We conducted a field survey of 142 plots at altitudes between 200 and 1,400 m a.s.l in the breeding season. A total of 2,771 individuals from 53 breeding bird species were recorded. Altitudinal patterns of species richness and density showed a hump-shaped pattern, indicating that the highest richness and density could be observed at moderate altitudes. Models constructed with 13 combinations of six variables demonstrated that species richness was positively correlated with vertical and horizontal habitat heterogeneity. Density was positively correlated with vertical, but not horizontal habitat heterogeneity, and negatively correlated with migratory bird ratio. No significant relationships were found between spring temperature and species richness or density. Therefore, the observed patterns in species richness support the hypothesis that habitat heterogeneity, rather than climate, is the main driver of species richness. Also, neither habitat heterogeneity nor climate hypotheses fully explains the observed patterns in density. However, vertical habitat heterogeneity does likely help explain observed patterns in density. The heterospecific attraction hypothesis did not apply to the distribution of birds along the altitudinal gradient. Appropriate management of vertical habitat heterogeneity, such as vegetation cover, should be maintained for the conservation of bird diversity in this area.

  1. Medicinal Plants Density Along an Altitudinal Gradient in and Around Ayubia National Park

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    Tariq, A.; Adnan, M.; Begum, S.

    2016-01-01

    Medicinal plants are an essential source of livelihood for many rural populations and are currently facing several threats of extinction in temperate Himalaya, such as excessive grazing and collection along altitudinal gradients. The present study was designed to investigate the species density of medicinal plants at different mid-altitude levels (2200, 2300, 2400, and 2500 m above the sea level (a.s.l.) between two forest-use types and to examine the possible association between medicinal plant densities and forest-stand structural variables along the altitudinal gradient. Factorial design analysis of variance showed that the densities of all medicinal plants differed significantly between the forest-use types (p<0.00) and elevation (p<0.00). Moreover, a significant interaction (p<0.04) was also observed between the forest-use types and elevation. In the old-growth forest, density of medicinal plants was 290/40 m/sup 2/ at the higher altitude (2500 m a.s.l.), approximately 1.5-fold less than the 475/40 m/sup 2/ density observed at lower altitude (2200 m a.s.l.). However, in derived woodland, density of medicinal plants at higher altitude was approximately 4-fold less than that at the lower altitude. At these altitudinal levels, medicinal plants densities, such as Valeriana jatamansi, were significantly higher under old-growth forest compared to derived woodland, where they were almost nonexistent. A rapid vulnerability assessment has also shown that Valeriana jatamansi and Viola canescens were highly vulnerable species. Litter cover was the influential variable that was most likely related to medicinal plant density. In conclusion, abundance of medicinal plants decreased along mid-altitude levels in both of the forest-use types. However, this decrease was extremely marked in the derived woodland, and this decline may be due to human activity. Hence, these factors must be considered in future studies to suggest protective measures that can be applied along

  2. Characteristics of soils in selected maize growing sites along altitudinal gradients in East African highlands

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    Elijah Njuguna

    2015-12-01

    Full Text Available Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P and other soil parameters (pH, organic carbon content, soil texture [i.e. % Sand, % Clay and % Silt], cation exchange capacity [CEC], electric conductivity [EC], and water holding capacity [HC]. Soil samples were taken from maize plots along three altitudinal gradients in East African highlands (namely Machakos Hills, Taita Hills and Mount Kilimanjaro characterized by graded changes in climatic conditions. For all transects, pH, Ca, K and Mg decreased with the increase in altitude. In contrast, % Silt, organic carbon content, Al and water holding capacity (HC increased with increasing altitude. The research provides information on the status of the physical–chemical characteristics of soils along three altitudinal ranges of East African Highlands and includes data available for further research.

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

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    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

  4. Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau

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    L. Lyu

    2017-06-01

    Full Text Available Latitudinal and altitudinal gradients can be utilized to forecast the impact of climate change on forests. To improve the understanding of how these gradients impact forest dynamics, we tested two hypotheses: (1 the change of the tree growth–climate relationship is similar along both latitudinal and altitudinal gradients, and (2 the time periods during which climate affects growth the most occur later towards higher latitudes and altitudes. To address this, we utilized tree-ring data from a latitudinal gradient in Finland and from two altitudinal gradients on the Tibetan Plateau. We analysed the latitudinal and altitudinal growth patterns in tree rings and investigated the growth–climate relationship of trees by correlating ring-width index chronologies with climate variables, calculating with flexible time windows, and using daily-resolution climate data. High latitude and altitude plots showed higher correlations between tree-ring chronologies and growing season temperature. However, the effects of winter temperature showed contrasting patterns for the gradients. The timing of the highest correlation with temperatures during the growing season at southern sites was approximately 1 month ahead of that at northern sites in the latitudinal gradient. In one out of two altitudinal gradients, the timing for the strongest negative correlation with temperature at low-altitude sites was ahead of treeline sites during the growing season, possibly due to differences in moisture limitation. Mean values and the standard deviation of tree-ring width increased with increasing mean July temperatures on both types of gradients. Our results showed similarities of tree growth responses to increasing seasonal temperature between latitudinal and altitudinal gradients. However, differences in climate–growth relationships were also found between gradients due to differences in other factors such as moisture conditions. Changes in the timing of the most

  5. Effects of phylogeny, leaf traits, and the altitudinal distribution of host plants on herbivore assemblages on congeneric Acer species.

    Science.gov (United States)

    Nakadai, Ryosuke; Murakami, Masashi; Hirao, Toshihide

    2014-08-01

    Historical, niche-based, and stochastic processes have been proposed as the mechanisms that drive community assembly. In plant-herbivore systems, these processes can correspond to phylogeny, leaf traits, and the distribution of host plants, respectively. Although patterns of herbivore assemblages among plant species have been repeatedly examined, the effects of these factors among co-occurring congeneric host plant species have rarely been studied. Our aim was to reveal the process of community assembly for herbivores by investigating the effects of phylogeny, leaf traits, and the altitudinal distribution of closely related host plants of the genus Acer. We sampled leaf functional traits for 30 Acer species in Japan. Using a newly constructed phylogeny, we determined that three of the six measured leaf traits (leaf thickness, C/N ratio, and condensed tannin content) showed a phylogenetic signal. In a field study, we sampled herbivore communities on 14 Acer species within an elevation gradient and examined relationships between herbivore assemblages and host plants. We found that herbivore assemblages were significantly correlated with phylogeny, leaf traits, phylogenetic signals, and the altitudinal distribution of host plants. Our results indicate that the interaction between historical and current ecological processes shapes herbivore community assemblages.

  6. Carbon stocks of three secondary coniferous forests along an altitudinal gradient on Loess Plateau in inland China

    Science.gov (United States)

    Liu, Ning; Nan, Hongwei

    2018-01-01

    Natural forests in inland China are generally distributed in montane area and secondary due to a semi-arid climate and past anthropogenic disturbances. However, quantification of carbon (C) stock in these forests and the role of altitude in determining C storage and its partition among ecosystem components are unclear. We sampled 54 stands of three secondary coniferous forests (Larix principis-rupprechtii (LP) forest, Picea meyerii (PM) forest and Pinus tabulaeformis (PT) forest) on Loess Plateau in an altitudinal range of 1200-2700m a.s.l. C stocks of tree layer, shrub layer, herb layer, coarse wood debris, forest floor and soil were estimated. We found these forests had relatively high total C stocks. Driven by both higher vegetation and soil C stocks, total C stocks of LP and PM forests in the high altitudinal range were 375.0 and 368.4 t C ha-1 respectively, significantly higher than that of PT forest in the low altitudinal range (230.2 t C ha-1). In addition, understory shrubs accounted for about 20% of total biomass in PT forest. The proportions of vegetation to total C stock were similar among in the three forests (below 45%), so were the proportions of soil C stock (over 54%). Necromass C stocks were also similar among these forests, but their proportions to total C stock were significantly lower in LP and PM forests (1.4% and 1.6%) than in PT forest (3.0%). Across forest types, vegetation biomass and soil C stock simultaneously increased with increasing altitude, causing fairly unchanged C partitioning among ecosystem components along the altitudinal gradient. Soil C stock also increased with altitude in LP and PT forests. Forest floor necromass decreased with increasing altitude across the three forests. Our results suggest the important role of the altitudinal gradient in C sequestration and floor necromass of these three forests in terms of alleviated water conditions and in soil C storage of LP and PM forests in terms of temperature change. PMID

  7. 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.

  8. 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

  9. Losses in superconducting multifilament composites under alternating changing fields

    International Nuclear Information System (INIS)

    Turck, B.

    1979-03-01

    The first part of this report presents a brief review of the losses in superconducting composites in a changing external field. The losses are expressed for a single triangular shaped pulse and for a field varying exponentially with time. The losses are calculated as a function of two important time constants. The first is due to the coupling currents between the filaments, the second is due to the eddy currents induced in the matrix. In the second part of the report, the case of an oscillating sinusoidal field is considered. In particular, in a rapidly varying field, several layers of filaments can be saturated by returning currents. Complete expressions of the losses are provided together with simplified expressions which enable one to calculate the losses in most cases. In the third part, a comparison between several kinds of conductors shows that in some cases the losses are reduced by increasing the twist pitch of the conductor

  10. Pulsed field losses and intentional quenches of superconducting coils

    International Nuclear Information System (INIS)

    Kim, S.H.

    1983-01-01

    Pulsed field losses of several 5-20 kJ coils have been measured under triangular field variations. The conductors, developed as potential subcables of 25-50 kA cables, consist of Cu wires and NbTi strands with or without CuNi barriers. Losses of soft-soldered subcables are compared with those of well-compacted cables. The coils were quenched intentionally by pulsing the coils above the critical current to observe loss variations due to possible conductor damage. The method of measurements, and effects of soldering and compactness of the conductors on the pulsed field losses will be presented

  11. Studies on Colombian cryptogams XX. A transect analysis of the bryophyte vegetation along an altitudinal gradient on the Sierra Nevada de Santa Marta, Colombia

    NARCIS (Netherlands)

    Reenen, van G.B.A.; Gradstein, S.R.

    1983-01-01

    Along an altitudinal transect on the northern slope of the Sierra Nevada de Santa Marta, Colombia, 500-4100 m, five altitudinal bryophyte zones are distinguished – four forest zones and one páramo zone – based on ecosystem relevé analysis concerning species presence, substrate preference and

  12. Asymmetric changes of growth and reproductive investment herald altitudinal and latitudinal range shifts of two woody species.

    Science.gov (United States)

    Matías, Luis; Jump, Alistair S

    2015-02-01

    Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of the geographical distribution of a species, where range expansions or contractions may occur. Current demographical status at geographical range limits can help us to predict population trends and their implications for the future distribution of the species. Thus, understanding the comparability of demographical patterns occurring along both altitudinal and latitudinal gradients would be highly informative. In this study, we analyse the differences in the demography of two woody species through altitudinal gradients at their southernmost distribution limit and the consistency of demographical patterns at the treeline across a latitudinal gradient covering the complete distribution range. We focus on Pinus sylvestris and Juniperus communis, assessing their demographical structure (density, age and mortality rate), growth, reproduction investment and damage from herbivory on 53 populations covering the upper, central and lower altitudes as well as the treeline at central latitude and northernmost and southernmost latitudinal distribution limits. For both species, populations at the lowermost altitude presented older age structure, higher mortality, decreased growth and lower reproduction when compared to the upper limit, indicating higher fitness at the treeline. This trend at the treeline was generally maintained through the latitudinal gradient, but with a decreased growth at the northern edge for both species and lower reproduction for P. sylvestris. However, altitudinal and latitudinal transects are not directly comparable as factors other than climate, including herbivore pressure or human management, must be taken into account if we are to understand how to infer latitudinal processes from altitudinal data. © 2014 John Wiley & Sons Ltd.

  13. Madicolous Chironomidae from the Brazilian Atlantic Forest: a checklist with notes on altitudinal distributions (Diptera, Insecta)

    Science.gov (United States)

    Shimabukuro, Erika Mayumi; Trivinho-Strixino, Susana

    2018-01-01

    Abstract Thin layers of water running over rocky surfaces are characteristic of madicolous habitats, which harbor a peculiar Chironomidae community. However, information on the identity, distribution, and ecology of madicolous chironomids in the Neotropical region are still sparse. The main purpose of this research is to reveal and contribute to the ecology of madicolous Chironomidae species, especially regarding their altitudinal distribution in the Atlantic Forest. Sampling was performed using our own designed emergence traps deployed from 0 to 2700 m a.s.l. in 70 sites in three mountains in southeastern Brazil. Sixty taxa of chironomids were collected and identified, of which only 22 are known to science. Most of the species showed a wider distribution than previously known, both in terms of geographic and altitudinal ranges, while others showed significant association with particular altitudinal bands (as evidenced by the indicator species analysis). Atlantic Forest mountainous regions are known to harbor one of the richest fauna in the world and have been suffering from several types of environmental impacts, including climate change, which will especially affect taxa living in specialized habitats. The narrow range of tolerance to environmental conditions verified for mountain species, and the fact that many of them are rare and endemic, make the conservation efforts in these areas indispensable. PMID:29706784

  14. Altitudinal and temporal distribution of Plagiometriona Spaeth, 1899 (Coleoptera, Chrysomelidae, Cassidinae) in a tropical forest in southeast Brazil.

    Science.gov (United States)

    Flinte, Vivian; de Freitas, Sama; de Macedo, Margarete Valverde; Monteiro, Ricardo Ferreira

    2011-01-01

    Species richness and abundance of seven Plagiometriona species on their host plants were studied along a single trail in the mountainous Serra dos Órgãos National Park in the State of Rio de Janeiro, Brazil. Six sites were chosen along an altitudinal gradient ranging from 1300 m to 2050 m, where all Solanaceae host plants were inspected in search of adults every two months from June 2006 to June 2007. Species richness did not vary clearly with altitude, but abundance increased up to 1800 m, where the highest mean host plant density was found, and abruptly decreased at the last elevational site. Most species showed a restricted distribution and just one occurred across the entire gradient. For at least four species, altitudinal distribution seems to be strongly related to host plant availability, while for the others it is difficult to access which factors are decisive, due to their low numbers. Only in October all species were found in the field, although February was the month with the highest total abundance. Over the course of the study, the greatest abundances were recorded from October to February, comprehending the hottest and rainiest months, and the lowest abundances were found from June to August, which include the coldest and driest months. Thus, species seasonal distribution, supported by other studies in the same area, seems to be related to the local climate.

  15. 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.

  16. Self-field AC losses in Bi-2223 superconducting tapes

    International Nuclear Information System (INIS)

    Mueller, K. H.; Leslie, K.E.

    1996-01-01

    Full text: The self-field AC loss in Bi-2223 silver sheathed tapes for AC currents of up to 100 A was measured at 77 K and frequencies of 60 Hz and 600 Hz using a lock-in amplifier. The frequency dependence indicated a purely hysteretic loss which can be well described in terms of the critical state model for a flat superconducting strip. The only parameter needed to predict the self-field AC loss is the critical current of the critical state. Because the loss voltage is extremely small compared with the inductive voltage, a very high accuracy of the lock-in amplifier phase setting is required. Unlike in loss measurements on cylindrical superconducting samples, in the case of the tape the measuring circuit leads have to be brought out from the surface forming a loop where the changing magnetic field induces an additional voltage. Only if the loop formed by the leads at the voltage tabs is large enough will the apparent power dissipation approach the real AC loss associated with the length of the sample probed

  17. Fast ion loss and radial electric field in high-aspect-ratio stellarator

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Sanuki, Heiji; Itoh, Sanae

    1992-01-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more close to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the selfconsistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhance the negative radial electric field, and reduce the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  18. Fast ion loss and radial electric field in Wendelstein VII-Λ stellarator

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Itoh, S.

    1991-10-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the self consistent electric field profile. The orbit loss become noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhances the negative radial electric field, and reduces the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  19. Floristic-functional variation of tree component along an altitudinal gradient in araucaria forest areas, in Southern Brazil.

    Science.gov (United States)

    Soboleski, Vanessa F; Higuchi, Pedro; Silva, Ana Carolina DA; Silva, Mariele A F DA; Nunes, Amanda S; Loebens, Rodineli; Souza, Karine DE; Ferrari, Jheniffer; Lima, Carla L; Kilca, Ricardo V

    2017-01-01

    We aimed to investigate the taxonomic and functional variations of tree component of Araucaria Forest (AF) areas located along an altitudinal gradient (700, 900 and 1,600 m asl), in the southern region of Brazil. The functional traits determined were leaf area, specific leaf area, wood density, maximum potential height and dispersal syndromes and deciduousness. The data were analyzed through a functional and taxonomic dissimilarity dendrograms, community-weighted mean trait values, parametric and nonparametric tests, and Principal Component Analysis. The largest floristic-structural similarity was observed between the lower altitude areas (700 and 900 m asl), whose Bray-Curtis distance was 0.63. The area at 700 m asl was characterized by a predominance of deciduous and semi-deciduous species, with a high number of self- and wind-dispersed species, whereas the area at 1,600 m asl exhibited a predominance of animal-dispersed and evergreen species. It was also observed that there were significant variations for leaf traits, basic wood density and maximum potential height. Over all altitudinal gradient, the ordinations indicated that there was no evidence of functional differentiation among dispersal and deciduousness groups. In conclusion, the evaluated Araucaria Forest areas presented high floristic-functional variation of the tree component along the altitudinal gradient.

  20. Temperature sensitivity and enzymatic mechanisms of soil organic matter decomposition along an altitudinal gradient on Mount Kilimanjaro

    Science.gov (United States)

    Blagodatskaya, Еvgenia; Blagodatsky, Sergey; Khomyakov, Nikita; Myachina, Olga; Kuzyakov, Yakov

    2016-02-01

    Short-term acceleration of soil organic matter decomposition by increasing temperature conflicts with the thermal adaptation observed in long-term studies. Here we used the altitudinal gradient on Mt. Kilimanjaro to demonstrate the mechanisms of thermal adaptation of extra- and intracellular enzymes that hydrolyze cellulose, chitin and phytate and oxidize monomers (14C-glucose) in warm- and cold-climate soils. We revealed that no response of decomposition rate to temperature occurs because of a cancelling effect consisting in an increase in half-saturation constants (Km), which counteracts the increase in maximal reaction rates (Vmax with temperature). We used the parameters of enzyme kinetics to predict thresholds of substrate concentration (Scrit) below which decomposition rates will be insensitive to global warming. Increasing values of Scrit, and hence stronger canceling effects with increasing altitude on Mt. Kilimanjaro, explained the thermal adaptation of polymer decomposition. The reduction of the temperature sensitivity of Vmax along the altitudinal gradient contributed to thermal adaptation of both polymer and monomer degradation. Extrapolating the altitudinal gradient to the large-scale latitudinal gradient, these results show that the soils of cold climates with stronger and more frequent temperature variation are less sensitive to global warming than soils adapted to high temperatures.

  1. 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: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.242, year: 2015

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

    Directory of Open Access Journals (Sweden)

    Lionel Hernández

    2012-03-01

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

  3. Anthocyanin Profile in Berries of Wild and Cultivated Vaccinium spp. along Altitudinal Gradients in the Alps.

    Science.gov (United States)

    Zoratti, Laura; Jaakola, Laura; Häggman, Hely; Giongo, Lara

    2015-10-07

    Vaccinium spp. berries provide some of the best natural sources of anthocyanins. In the wild bilberry (Vaccinium myrtillus L.), a clear increasing trend in anthocyanin biosynthesis has been reported toward northern latitudes of Europe, but studies related to altitude have given contradictory results. The present study focused on the anthocyanin composition in wild bilberries and highbush blueberry (Vaccinium corymbosum L. cv. Brigitta Blue) growing along altitudinal gradients in the Alps of northern Italy. Our results indicate an increasing accumulation of anthocyanins in bilberries along an altitudinal gradient of about 650 m. The accumulation was due to a significant increase in delphinidin and malvidin glycosides, whereas the accumulation of cyanidin and peonidin glycosides was not affected by altitude. Seasonal differences, especially temperature, had a major influence on the accumulation of anthocyanins in blueberries.

  4. The genus morpho in colombia: I. species present in colombia, and their geographic and altitudinal distribution El genero Morpho en Colombia: I. especies presentes en Colombia, distribución geográfica y altitudinal

    Directory of Open Access Journals (Sweden)

    Rodríguez Claudia

    1994-06-01

    Full Text Available This work puts together the results of six studies carried out in Colombia on the genus Morpho, with a revised description of. the species found in Colombia based on color patterns and mal e
    genitalia. Biological and ecological data are included, such as geographic and altitudinal distribution, habitat, habits and behavior, and annotated comments on each of the 24 species.
    The work features drawings of genitalia for each species, some of which had not been published before. This first issue covers the distribution of species found in Colombia.En este trabajo, se presentan los resultados de los estudios sobre el género Morphoen Colombia recopilados (6, con una redescripción de las especies del género que habitan en Colombia, con base en las características de patrones de
    coloración y genitalias. Simultáneamente, se incluyen datos biológicos y ecológicos, como: distribución geográfica y altitudinal, hábitos, hábitat y comportamiento, además de otras anotaciones y comentarios de cada una de las 24 especies; se adicionan gráficos simplificados de las genitalias de cada una de las especies, muchas de las cuales no habían sido ilustradas anteriormente y, finalmente, se incluyen los registros de diferentes colecciones. En esta primera entrega, se señala la distribución geográfica y altitudinal de las especies que habitan en Colombia.

  5. Carbon and nitrogen dynamics of soil and litter along an altitudinal gradient in Atlantic Forest

    Science.gov (United States)

    Piccolo, M. D.; Martins, S. C.; Camargo, P. B.; Carmo, J. B.; Sousa Neto, E.; Martinelli, L. A.

    2008-12-01

    The Ombrophylus Dense Forest or Atlantic Forest is the second most important Biome in extension of Brazil, and it is considered a hot-spot in terms of biodiversity. It is localized in Brazilian Coast, and it covered originally 1.2 million km2, but currently only 8% of the original forest remains. The study was carried out in Sao Paulo State, Brazil (23° 24' S and 45° 11' W). The studied areas were: Restinga Vegetation (RV), 5 m above sea level; Low Altitude Ombrophylus Dense Forest (LAODF), 100 m asl; Submontane Ombrophylus Dense Forest (SODF), 600m asl and; Montane Ombrophylus Dense Forest (MODF), 1000 m asl. The aim of this study was to evaluate the effect of altitudinal gradient, with specific phytophysiognomies, on C and N dynamics in the soil and litter at Atlantic Forest. A sampling area of 1 ha was subdivided in contiguous sub- parcels (10 x 10 m). The forest floor litter accumulated (0.06 m2) was collected monthly (n=60), during 12 months, in each phytophysiognomies. Soils samples (0-0.05m depth) were collected (n=32) from square regular grids, 30 m away from each other. Changes in litter contents of C and N were not detected along the altitudinal gradient, and the values observed were 400 and 15g kg-1 for C and N, respectively. Litter ä13C values did not change significantly with the altitudinal gradient and were represented by C3 plants values. The C and N stocks were high in the clay soils (LAODF, SODF and MODF) when compared to sandy soil (RV). The soil C stocks (24 to 30 Mg ha-1) were similar among the altitudinal gradients, except RV (16 Mg ha-1). The areas of elevated altitude (MODF and SODF) showed high N stocks (2.3 Mg ha-1), followed by LAODF (1.8Mg ha-1) and RV (0.9Mg ha-1). In all altitudes there was 13C enrichment with soil depth, and it can be explained by the different fractions of the organic matter distributed along the soil profile, and also due the effect of the isotopic dilution between the forest floor litter and the soil.

  6. Altitudinal and temporal distribution of Plagiometriona Spaeth, 1899 (Coleoptera, Chrysomelidae, Cassidinae in a tropical forest in southeast Brazil

    Directory of Open Access Journals (Sweden)

    Vivian Flinte

    2011-12-01

    Full Text Available Species richness and abundance of seven Plagiometriona species on their host plants were studied along a single trail in the mountainous Serra dos Órgãos National Park in the State of Rio de Janeiro, Brazil. Six sites were chosen along an altitudinal gradient ranging from 1300 m to 2050 m, where all Solanaceae host plants were inspected in search of adults every two months from June 2006 to June 2007. Species richness did not vary clearly with altitude, but abundance increased up to 1800 m, where the highest mean host plant density was found, and abruptly decreased at the last elevational site. Most species showed a restricted distribution and just one occurred across the entire gradient. For at least four species, altitudinal distribution seems to be strongly related to host plant availability, while for the others it is difficult to access which factors are decisive, due to their low numbers. Only in October all species were found in the field, although February was the month with the highest total abundance. Over the course of the study, the greatest abundances were recorded from October to February, comprehending the hottest and rainiest months, and the lowest abundances were found from June to August, which include the coldest and driest months. Thus, species seasonal distribution, supported by other studies in the same area, seems to be related to the local climate.

  7. 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.

  8. Plasma Heating and Losses in Toroidal Multipole Fields

    International Nuclear Information System (INIS)

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

    1974-01-01

    The heating and loss of plasmas have been studied in three pulsed, toroidal multipole devices: a large levitated octupole, a small supported octupole and a very small supported quadrupole. Plasmas are produced by gun injection and heated by electron and ion cyclotron resonance heating and ohmic heating. Electron cyclotron heating rates have been measured over a wide range of parameters, and the results are in quantitative agreement with stochastic heating theory. Electron cyclotron resonance heating produces ions with energies larger than predicted by theory. With the addition of a toroidal field, ohmic heating gives densities as high as 10 13 cm -3 in the toroidal quadrupole and 10 12 cm -3 in the small octupole. Plasma losses for n=5 x 10 9 cm -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

  9. Natural course of visual field loss in patients with Type 2 Usher syndrome.

    Science.gov (United States)

    Fishman, Gerald A; Bozbeyoglu, Simge; Massof, Robert W; Kimberling, William

    2007-06-01

    To evaluate the natural course of visual field loss in patients with Type 2 Usher syndrome and different patterns of visual field loss. Fifty-eight patients with Type 2 Usher syndrome who had at least three visual field measurements during a period of at least 3 years were studied. Kinetic visual fields measured on a standard calibrated Goldmann perimeter with II4e and V4e targets were analyzed. The visual field areas in both eyes were determined by planimetry with the use of a digitalizing tablet and computer software and expressed in square inches. The data for each visual field area measurement were transformed to a natural log unit. Using a mixed model regression analysis, values for the half-life of field loss (time during which half of the remaining field area is lost) were estimated. Three different patterns of visual field loss were identified, and the half-life time for each pattern of loss was calculated. Of the 58 patients, 11 were classified as having pattern type I, 12 with pattern type II, and 14 with pattern type III. Of 21 patients whose visual field loss was so advanced that they could not be classified, 15 showed only a small residual central field (Group A) and 6 showed a residual central field with a peripheral island (Group B). The average half-life times varied between 3.85 and 7.37 for the II4e test target and 4.59 to 6.42 for the V4e target. There was no statistically significant difference in the half-life times between the various patterns of field loss or for the test targets. The average half-life times for visual field loss in patients with Usher syndrome Type 2 were statistically similar among those patients with different patterns of visual field loss. These findings will be useful for counseling patients with Type 2 Usher syndrome as to their prognosis for anticipated visual field loss.

  10. 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.

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

    International Nuclear Information System (INIS)

    Halbritter, J.

    1976-02-01

    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 f 2 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.) [de

  12. Morphological and colour morph clines along an altitudinal gradient in the meadow grasshopper Pseudochorthippus parallelus.

    Science.gov (United States)

    Köhler, Günter; Samietz, Jörg; Schielzeth, Holger

    2017-01-01

    Many animals show altitudinal clines in size, shape and body colour. Increases in body size and reduction in the length of body appendices in colder habitats are usually attributed to improved heat conservation at lower surface-to-volume ratios (known as Bergmann's and Allen's rule, respectively). However, the patterns are more variable and sometimes reversed in small ectotherms that are affected by shortened growing seasons. Altitude can also affect colouration. The thermal melanism hypothesis predicts darker colours under cooler conditions because of a thermoregulatory advantage. Darker colours may also be favoured at high altitudes for reasons of UV protection or habitat-dependent crypsis. We studied altitudinal variation in morphology and colour in the colour-polymorphic meadow grasshopper Pseudochorthippus parallelus based on 563 individuals from 17 populations sampled between 450 and 2,500 m asl. Pronotum length did not change with altitude, while postfemur length decreased significantly in both sexes. Tegmen (forewing) length decreased in males, but not in females. The results indicate that while body size, as best quantified by pronotum length, was remarkably constant, extended appendices were reduced at high altitudes. The pattern thus follows Allen's rule, but neither Bergmann's nor converse Bergmann's rule. These results indicate that inference of converse Bergmann's rule based on measurements from appendices should be treated with some caution. Colour morph ratios showed significant changes in both sexes from lowland populations dominated by green individuals to high-altitude populations dominated by brown ones. The increase of brown morphs was particularly steep between 1,500 and 2,000 m asl. The results suggest shared control of colour in males and females and local adaptation along the altitudinal gradient following the predictions of the thermal melanism hypothesis. Interestingly, both patterns, the reduction of body appendices and the higher

  13. Poloidal flux loss in a field-reversed theta pinch

    International Nuclear Information System (INIS)

    Hoffman, A.L.; Milroy, R.D.; Steinhauer, L.C.

    1981-01-01

    Poloidal flux loss has been measured in field-reversed configurations and related to anomalous resistivity near the magnetic field null. The results indicate that mechanisms in addition to the lower-hybrid drift instability are affecting transport

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

    International Nuclear Information System (INIS)

    Hsiao, M.Y.

    1983-01-01

    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

  15. 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...

  16. Energy loss of ions by electric-field fluctuations in a magnetized plasma.

    Science.gov (United States)

    Nersisyan, Hrachya B; Deutsch, Claude

    2011-06-01

    The results of a theoretical investigation of the energy loss of charged particles in a magnetized classical plasma due to the electric-field fluctuations are reported. The energy loss for a test particle is calculated through the linear-response theory. At vanishing magnetic field, the electric-field fluctuations lead to an energy gain of the charged particle for all velocities. It has been shown that in the presence of strong magnetic field, this effect occurs only at low velocities. In the case of high velocities, the test particle systematically loses its energy due to the interaction with a stochastic electric field. The net effect of the fluctuations is the systematic reduction of the total energy loss (i.e., the sum of the polarization and stochastic energy losses) at vanishing magnetic field and reduction or enhancement at strong field, depending on the velocity of the particle. It is found that the energy loss of the slow heavy ion contains an anomalous term that depends logarithmically on the projectile mass. The physical origin of this anomalous term is the coupling between the cyclotron motion of the plasma electrons and the long-wavelength, low-frequency fluctuations produced by the projectile ion. This effect may strongly enhance the stochastic energy gain of the particle.

  17. 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.

  18. 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

    Spatial fingerprints of climate change on tree species distribution are usually detected at latitudinal or altitudinal extremes (arctic or alpine tree line), where temperatures play a key role in tree species distribution. However, early detection of recent climate change effects on tree species...... 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...... range from lowlands to the subalpine vegetation belt (50-2250 m a.s.l.) and spanning the latitudinal gradient from northern temperate to southern Mediterranean forests. We simultaneously identified seedlings and adults within the same vegetation plots. These twin observations gave us the equivalent...

  19. Distribución y diversidad de colémbolos (Hexapoda: Collembola en el gradiente altitudinal de un bosque templado en México

    Directory of Open Access Journals (Sweden)

    Arturo García-Gómez

    2011-03-01

    Full Text Available Los colémbolos son fragmentadores importantes de la hojarasca, presentan diferentes patrones de distribución a lo largo de un gradiente altitudinal. El objetivo del presente trabajo es determinar la diversidad y distribución de Collembola en el volcán Iztaccíhuatl. Para ello, se realizaron cuatro muestreos, a lo largo de un año en cuatro pisos altitudinales (I=2 753, II=3 015, III=3 250 y IV=3 687m.s.n.m. y se calcularon los índices de diversidad de Shannon, equitatividad de Pielou y dominancia de Simpson, para compararlos mediante una prueba de t modificada. Los resultados muestran al piso III como el más diverso, y la mayor equitatividad se encuentra en el II. Además, se hallaron diferencias significativas entre los pisos II-III (t0.01, 187=4.11, pDistribution and diversity of springtails (Hexapoda: Collembola on the altitudinal gradient of a temperate forest in Mexico. Mountain ecosystems have shown slow mineralization activity due to weather conditions, and to some groups with arthropods with special roles. The Collembola is an important group for litter fragmentation, showing different distribution patterns. The objective of the present study was to determine the diversity of Collembola along a volcano altitudinal gradient. For this, four sampling expeditions evaluated four altitudinal levels (I=2 753, II=3 015, III=3 250 and IV=3 687 masl in Iztaccihuatl Volcano, from November 2003, and March, June and August 2004. Shannon diversity (H’, Pielou evenness (J’ and Simpson dominance (1/λ indices were calculated. The similarity between the associations of springtails between the sampling sites was evaluated by a cluster analysis using the Pearson correlation coefficient, as distance and the unpaired arithmetic averages (UPGMA as amalgamation method. A total of 24 075 springtails, distributed in 12 families, 46 genera and 86 species was collected. The higher species abundance was found at the altitudinal area II. The lowest

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Magnusson, Niklas

    2016-01-01

    Superconducting (SC) synchronous generators are proposed as a promising candidate for 10-20-MW direct-drive wind turbines because they can have low weights and small sizes. A common way of designing an SC machine is to use SC wires with high current-carrying capability in the dc field winding...... and the ac armature winding is made with copper conductors. In such generators, the dc field winding is exposed to ac magnetic field ripples due to space harmonics from the armature. In generator design phases, the ac loss caused by these ripple fields needs to be evaluated to avoid local overheating...... and an excessive cooling budget. To determine the applicability of different design solutions in terms of ac losses, this paper estimates the ac loss level of 10-MW wind generator designs employing a MgB2 SC field winding. The effects on ac losses are compared between nonmagnetic and ferromagnetic teeth...

  3. Ammonia volatilization losses from paddy fields under controlled irrigation with different drainage treatments.

    Science.gov (United States)

    He, Yupu; Yang, Shihong; Xu, Junzeng; Wang, Yijiang; Peng, Shizhang

    2014-01-01

    The effect of controlled drainage (CD) on ammonia volatilization (AV) losses from paddy fields under controlled irrigation (CI) was investigated by managing water table control levels using a lysimeter. Three drainage treatments were implemented, namely, controlled water table depth 1 (CWT1), controlled water table depth 2 (CWT2), and controlled water table depth 3 (CWT3). As the water table control levels increased, irrigation water volumes in the CI paddy fields decreased. AV losses from paddy fields reduced due to the increases in water table control levels. Seasonal AV losses from CWT1, CWT2, and CWT3 were 59.8, 56.7, and 53.0 kg N ha(-1), respectively. AV losses from CWT3 were 13.1% and 8.4% lower than those from CWT1 and CWT2, respectively. A significant difference in the seasonal AV losses was confirmed between CWT1 and CWT3. Less weekly AV losses followed by TF and PF were also observed as the water table control levels increased. The application of CD by increasing water table control levels to a suitable level could effectively reduce irrigation water volumes and AV losses from CI paddy fields. The combination of CI and CD may be a feasible water management method of reducing AV losses from paddy fields.

  4. Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Kumar Munesh

    2009-08-01

    Full Text Available Abstract Background The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC. However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known. Results This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora and subtropical (Pinus roxburghii forests, respectively. Conclusion The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation

  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. Particle loss from magnetic cusp field

    International Nuclear Information System (INIS)

    Namba, C.; Kawamura, T.; Obayashi, H.

    1974-12-01

    The motion of charged particles in an axially symmetric magnetic field of cusp configuration is studied by means of numerical calculations. A particular attention is paid to a non-adiabatic zone. The computer results are compared with a simplified loss cone model and it is shown that there is a critical value of non-adiabaticity parameter which defines an effective size of the non-adiabatic zone. (auth.)

  7. Altitudinal, seasonal and interannual shifts in microbial communities and chemical composition of soil organic matter in Alpine forest soils

    Czech Academy of Sciences Publication Activity Database

    Siles, J.A.; Cajthaml, Tomáš; Filipová, Alena; Minerbi, S.; Margesin, R.

    2017-01-01

    Roč. 112, SEP 2017 (2017), s. 1-13 ISSN 0038-0717 Institutional support: RVO:61388971 Keywords : Elevational (altitudinal) gradient * Forest * Microbial communit Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.857, year: 2016

  8. Alternating field losses in Nb3Sn multifilamentary superconductor

    International Nuclear Information System (INIS)

    Murphy, J.H.; Deis, D.W.; Shaw, B.J.; Walker, M.S.

    1975-01-01

    Transverse alternating field losses at 4.2K have been measured from 0.5 Hz to 10 kHz in a Nb 3 Sn multifilamentary superconductor in bias fields to 5 Tesla. The 0.020 inch diameter sample was prepared by heat treating a Cu, Nb-1 wt percent Zr, CuSn composite at 700 0 C for 20 hours to form Nb 3 Sn on the inside surface of the annular filaments. Metallurgical studies have been made to determine the Sn distribution and to estimate the thickness of the Nb 3 Sn layer. The I/sub c/-H curve and resistive and inductive transition curves are presented. The losses are analyzed with respect to the present loss theories using the conductor characteristics measured and excellent agreement between experiment and theory is achieved. 1 table, 6 figures

  9. Medical review licensing outcomes in drivers with visual field loss in Victoria, Australia

    Science.gov (United States)

    Muir, Carlyn; Charlton, Judith L; Odell, Morris; Keeffe, Jill; Wood, Joanne; Bohensky, Megan; Fildes, Brian; Oxley, Jennifer; Bentley, Sharon; Rizzo, Matthew

    2017-01-01

    Background Good vision is essential for safe driving and studies have associated visual impairment with an increased crash risk. Currently, there is little information about the medical review of drivers with visual field loss. This study examines the prevalence of visual field loss among drivers referred for medical review in one Australian jurisdiction and investigates factors associated with licence outcome in this group. Methods A random sample of 10,000 (31.25 per cent) medical review cases was extracted for analysis from the Victorian licensing authority. Files were screened for the presence of six visual field-related medical conditions. Data were captured on a range of variables, including referral source, age, gender, health status, crash history and licence outcome. Prevalence analyses were univariate and descriptive. Logistic regression was used to assess factors associated with licence outcomes in the visual field loss group. Results Approximately 1.9 per cent of the 10,000 medical review cases screened had a visual field loss condition identified (n=194). Among the visual field loss group, 57.2 per cent were permitted to continue driving (conditional/unconditional licence). Primary referral sources were the police, self-referrals and general medical practitioners. Key factors associated with licence test outcomes were visual field condition, age group, crash involvement and referral to the Driver Licensing Authority’s Medical Advisors. Those who were younger had a crash involvement triggering referral and those who were referred to the Medical Advisors were more likely to have a positive licensing outcome. Conclusion The evidence base for making licensing decisions is complicated by the variable causes, patterns, progressions and measuring technologies for visual field loss. This study highlighted that the involvement of an expert medical advisory service in Victoria resulted in an increased likelihood that drivers with visual field loss will be

  10. Field of dreamers and dreamed-up fields: functional and fake perimetry.

    Science.gov (United States)

    Thompson, J C; Kosmorsky, G S; Ellis, B D

    1996-01-01

    Hysterical and malingering patients can manifest visual field defects on perimetry (visual field testing), including defects suggestive of true visual pathway pathology. It has been shown that control subjects can easily imitate some pathologic defects with automated, computed perimetry. The authors sought to determine whether subjects could imitate the same pathologic defect with manual and automated perimetry. Six subjects posed as patients with neurologic problems. They had manual perimetry with both an experienced and inexperienced technician followed by automated perimetry. They were later interviewed about the methods of the technicians and the difficulty of the exercise. Four of six subjects easily imitated the assigned defects with both technicians on manual perimetry and with automated perimetry. These included quadrantic, altitudinal, hemianopic, and enlarged blind-spot defects. Two subjects who were assigned cecocentral and paracentral scotomas instead produced enlarged blind spots by manual perimetry and defects suggestive of chiasmal pathology by automated perimetry. Paradoxically, some subjects found that experienced technicians were easier to fool than inexperienced technicians because of the systematic way in which experienced technicians defined defects. With minimal coaching, some subjects can imitate visual fields with enlarged blind spots, quadrantic, hemianopic, and altitudinal defects with ease and reproducibility by both automated and manual perimetry. Cecocentral and paracentral scotomas are harder to imitate but may be mistaken as representing chiasmal pathology. Paradoxically, experienced technicians may not be better at detecting hysterical or malingering individuals.

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

    Science.gov (United States)

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  12. Morphological and colour morph clines along an altitudinal gradient in the meadow grasshopper Pseudochorthippus parallelus.

    Directory of Open Access Journals (Sweden)

    Günter Köhler

    Full Text Available Many animals show altitudinal clines in size, shape and body colour. Increases in body size and reduction in the length of body appendices in colder habitats are usually attributed to improved heat conservation at lower surface-to-volume ratios (known as Bergmann's and Allen's rule, respectively. However, the patterns are more variable and sometimes reversed in small ectotherms that are affected by shortened growing seasons. Altitude can also affect colouration. The thermal melanism hypothesis predicts darker colours under cooler conditions because of a thermoregulatory advantage. Darker colours may also be favoured at high altitudes for reasons of UV protection or habitat-dependent crypsis. We studied altitudinal variation in morphology and colour in the colour-polymorphic meadow grasshopper Pseudochorthippus parallelus based on 563 individuals from 17 populations sampled between 450 and 2,500 m asl. Pronotum length did not change with altitude, while postfemur length decreased significantly in both sexes. Tegmen (forewing length decreased in males, but not in females. The results indicate that while body size, as best quantified by pronotum length, was remarkably constant, extended appendices were reduced at high altitudes. The pattern thus follows Allen's rule, but neither Bergmann's nor converse Bergmann's rule. These results indicate that inference of converse Bergmann's rule based on measurements from appendices should be treated with some caution. Colour morph ratios showed significant changes in both sexes from lowland populations dominated by green individuals to high-altitude populations dominated by brown ones. The increase of brown morphs was particularly steep between 1,500 and 2,000 m asl. The results suggest shared control of colour in males and females and local adaptation along the altitudinal gradient following the predictions of the thermal melanism hypothesis. Interestingly, both patterns, the reduction of body appendices and

  13. Can DMCO Detect Visual Field Loss in Neurological Patients? A Secondary Validation Study

    DEFF Research Database (Denmark)

    Olsen, Ane Sophie; Steensberg, Alvilda Thougaard; la Cour, Morten

    2017-01-01

    Unrecognized visual field loss is caused by a range of blinding eye conditions as well as serious brain diseases. The commonest cause of asymptomatic visual field loss is glaucoma. No screening tools have been proven cost-effective. Damato Multifixation Campimetry Online (DMCO), an inexpensive...... online test, has been evaluated as a future cost-beneficial tool to detect glaucoma. To further validate DMCO, this study aimed to test DMCO in a preselected population with neurological visual field loss. Methods : The study design was an evaluation of a diagnostic test. Patients were included...... if they had undergone surgery for epilepsy during 2011-2014, resulting in visual field loss. They were examined with DMCO and results were compared with those obtained with the Humphrey Field Analyzer (30:2 SITA-Fast). DMCO sensitivity and specificity were estimated with 95% confidence intervals. Results...

  14. [Altitudinal patterns of species richness and species range size of vascular plants in Xiaolong- shan Reserve of Qinling Mountain: a test of Rapoport' s rule].

    Science.gov (United States)

    Zheng, Zhi; Gong, Da-Jie; Sun, Cheng-Xiang; Li, Xiao-Jun; Li, Wan-Jiang

    2014-09-01

    Altitudinal patterns of species richness and species range size and their underlying mechanisms have long been a key topic in biogeography and biodiversity research. Rapoport's rule stated that the species richness gradually declined with the increasing altitude, while the species ranges became larger. Using altitude-distribution database from Xiaolongshan Reverse, this study explored the altitudinal patterns of vascular plant species richness and species range in Qinling Xiaolongshan Reserve, and examined the relationships between species richness and their distributional middle points in altitudinal bands for different fauna, taxonomic units and growth forms and tested the Rapoport's rule by using Stevens' method, Pagel's method, mid-point method and cross-species method. The results showed that the species richness of vascular plants except small-range species showed a unimodal pattern along the altitude in Qinling Xiaolongshan Reserve and the highest proportion of small-range species was found at the lower altitudinal bands and at the higher altitudinal bands. Due to different assemblages and examining methods, the relationships between species distributing range sizes and the altitudes were different. Increasing taxonomic units was easier to support Rapoport's rule, which was related to niche differences that the different taxonomic units occupied. The mean species range size of angiosperms showed a unimodal pattern along the altitude, while those of the gymnosperms and pteridophytes were unclearly regular. The mean species range size of the climbers was wider with the increasing altitude, while that of the shrubs which could adapt to different environmental situations was not sensitive to the change of altitude. Pagel's method was easier to support the Rapoport's rule, and then was Steven's method. On the contrary, due to the mid-domain effect, the results of the test by using the mid-point method showed that the mean species range size varied in a unimodal

  15. Soil carbon stocks along an altitudinal gradient in different land-use categories in Lesser Himalayan foothills of Kashmir

    Science.gov (United States)

    Shaheen, H.; Saeed, Y.; Abbasi, M. K.; Khaliq, A.

    2017-04-01

    The carbon sequestration potential of soils plays an important role in mitigating the effect of climate change, because soils serve as sinks for atmospheric carbon. The present study was conducted to estimate the carbon stocks and their variation with altitudinal gradient in the Lesser Himalayan foothills of Kashmir. The carbon stocks were estimated in different land use categories, namely: closed canopy forests, open forests, disturbed forests, and agricultural lands within the altitudinal range from 900 to 2500 m. The soil carbon content was determined by the Walkley-Black titration method. The average soil carbon stock was found to be 2.59 kg m-2. The average soil carbon stocks in closed canopy forests, open forests, and disturbed forests were 3.39, 2.06, and 2.86 kg m-2, respectively. The average soil carbon stock in the agricultural soils was 2.03 kg m-2. The carbon stocks showed a significant decreasing trend with the altitudinal gradient with maximum values of 4.13 kg m-2 at 900-1200 m a.s.l. and minimum value of 1.55 kg m-2 at 2100-2400 m a.s.l. The agricultural soil showed the least carbon content values indicating negative impacts of soil plowing, overgrazing, and soil degradation. Lower carbon values at higher altitudes attest to the immature character of forest stands, as well as to degradation due to immense fuel wood extraction, timber extraction, and harsh climatic conditions. The study indicates that immediate attention is required for the conservation of rapidly declining carbon stocks in agricultural soils, as well as in the soils of higher altitudes.

  16. Altitudinal gradient effect on morphometric variation and leaf symmetry of Platanus mexicana Moric

    OpenAIRE

    Dulce Ma. Galván-Hernández; J. Armando Lozada-García; Norma Flores-Estévez; Jorge Galindo-González; S. Mario Vázquez-Torres

    2015-01-01

    La variación morfométrica y simetría foliar de una población de Platanus mexicana se caracterizaron en un gradiente altitudinal ripario del estado de Veracruz. Ocho caracteres morfométricos se evaluaron en 1,800 hojas provenientes de 15 individuos por sitio (70, 200, 600 y 1,700 m de altitud). Las diferencias morfométricas entre sitios (F(24, 5189) = 21.1, P < 0.05) se determinaron con un análisis de funciones discriminantes. Los caracteres relacionados con el largo y ancho de las hojas deter...

  17. Self-consistent analysis of radial electric field and fast ion losses in CHS Torsatron/Heliotron

    International Nuclear Information System (INIS)

    Sanuki, H.; Itoh, K.; Itoh, S.

    1992-09-01

    A self-consistent analysis is developed to determine the radial electric field and loss cone boundary in Torsatron/Heliotron plasmas under the influence of non-classical ion losses such as the loss cone loss ans charge exchange loss of fast ions with neutrals. Analysis is applied to the NBI heated plasmas in the Compact Helical System (CHS) device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses caused 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, change exchange loss and bulk heating is evaluated by using the self-consistent electric field profile. On-going experiments in the CHS device are briefly introduced. (author)

  18. 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...

  19. Estimating the magnitude of prediction uncertainties for field-scale P loss models

    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, an uncertainty analysis for the Annual P Loss Estima...

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

    Science.gov (United States)

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  1. Comparing an Annual and a Daily Time-Step Model for Predicting Field-Scale Phosphorus Loss.

    Science.gov (United States)

    Bolster, Carl H; Forsberg, Adam; Mittelstet, Aaron; Radcliffe, David E; Storm, Daniel; Ramirez-Avila, John; Sharpley, Andrew N; Osmond, Deanna

    2017-11-01

    A wide range of mathematical models are available for predicting phosphorus (P) losses from agricultural fields, ranging from simple, empirically based annual time-step models to more complex, process-based daily time-step models. In this study, we compare field-scale P-loss predictions between the Annual P Loss Estimator (APLE), an empirically based annual time-step model, and the Texas Best Management Practice Evaluation Tool (TBET), a process-based daily time-step model based on the Soil and Water Assessment Tool. We first compared predictions of field-scale P loss from both models using field and land management data collected from 11 research sites throughout the southern United States. We then compared predictions of P loss from both models with measured P-loss data from these sites. We observed a strong and statistically significant ( loss between the two models; however, APLE predicted, on average, 44% greater dissolved P loss, whereas TBET predicted, on average, 105% greater particulate P loss for the conditions simulated in our study. When we compared model predictions with measured P-loss data, neither model consistently outperformed the other, indicating that more complex models do not necessarily produce better predictions of field-scale P loss. Our results also highlight limitations with both models and the need for continued efforts to improve their accuracy. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon

    Directory of Open Access Journals (Sweden)

    Toto Jean-Claude

    2010-05-01

    Full Text Available Abstract Background Highland areas of Africa are mostly malaria hypoendemic, due to climate which is not appropriate for anophelines development and their reproductive fitness. In view of designing a malaria control strategy in Western Cameroon highlands, baseline data on anopheline species bionomics were collected. Methods Longitudinal entomological surveys were conducted in three localities at different altitudinal levels. Mosquitoes were captured when landing on human volunteers and by pyrethrum spray catches. Sampled Anopheles were tested for the presence of Plasmodium circumsporozoite proteins and their blood meal origin with ELISA. Entomological parameters of malaria epidemiology were assessed using Mac Donald's formula. Results Anopheline species diversity and density decreased globally from lowland to highland. The most aggressive species along the altitudinal transect was Anopheles gambiae s.s. of S molecular form, followed in the lowland and on the plateau by An. funestus, but uphill by An. hancocki. An. gambiae and An. ziemanni exhibited similar seasonal biting patterns at the different levels, whereas different features were observed for An. funestus. Only indoor resting species could be captured uphill; it is therefore likely that endophilic behaviour is necessary for anophelines to climb above a certain threshold. Of the ten species collected along the transect, only An. gambiae and An. funestus were responsible for malaria transmission, with entomological inoculation rates (EIR of 90.5, 62.8 and zero infective bites/human/year in the lowland, on the plateau and uphill respectively. The duration of gonotrophic cycle was consistently one day shorter for An. gambiae as compared to An. funestus at equal altitude. Altitudinal climate variations had no effect on the survivorship and the subsequent life expectancy of the adult stage of these malaria vectors, but most probably on aquatic stages. On the contrary increasing altitude

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 Neel 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.

  4. Alternating current loss calculation in a high-TC superconducting transmission cable considering the magnetic field distribution

    International Nuclear Information System (INIS)

    Noji, H; Haji, K; Hamada, T

    2003-01-01

    We have calculated the alternating current (ac) losses of a 114 MVA high-T C superconducting (HTS) transmission cable using an electric-circuit (EC) model. The HTS cable is fabricated by Tokyo Electric Power Company and Sumitomo Electric Industries, Ltd. The EC model is comprised of a resistive part and an inductive part. The resistive part is obtained by the approximated Norris equation for a HTS tape. The Norris equation indicates hysteresis losses due to self-fields. The inductive part has two components, i.e. inductances related to axial fields and those related to circumferential fields. The layer currents and applied fields of each layer were calculated by the EC model. By using both values, the ac losses of the one-phase HTS cable were obtained by calculation considering the self-field, the axial field and the circumferential field of the HTS tape. The measured ac loss transporting 1 kA rms is 0.7 W m -1 ph -1 , which is equal to the calculation. The distribution of each layer loss resembles in shape the distribution of the circumferential field in each layer, which indicates that the circumferential fields strongly influence the ac losses of the HTS cable

  5. Spatial Association of Wetlands over Physical Variants in Barind Tract of West Bengal, India.

    Directory of Open Access Journals (Sweden)

    Rajeb Tarani Das

    2016-07-01

    Full Text Available Abstract: Barind tract of west Bengal is an uplifted old alluvial plain area where only <1 percent area is covered by wetland. Present paper concentrates on general understanding of wetland association with different geographical settings like geological, geomorphological lithological structure and altitudinal gradations. Detail investigation reveals that geological and morphological structure do not have deep influence on wetland formation and their distribution in particular favourable sub-region. But altitudinal control on wetland is noticeable. An irregular distribution of wetland is found throughout the region because of multi parametric influence on it. In recent decades wetlands in barind tract has been undergoing into rapid loss. Continuous encroachment of agricultural field and newly built-up area to wetland are considered as main causes of wetland loss in barind tract.

  6. UREDINALES (RUST FUNGI BIOTA OF THE PARQUE NACIONAL DO ITATIAIA, BRAZIL: AN ANALYSIS OF COMPOSITION, SPECIES DIVERSITY AND ALTITUDINAL DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    Salazar Yepes Mauricio

    2013-07-01

    Full Text Available The present study analyzed the composition, species diversity, and altitudinal distributionof rust fungi (Uredinales collected in the Parque Nacional do Itatiaia, Brazil.Results were compared with other Atlantic Forest locations, the São Paulo Cerradoand some other tropical regions. The Uredinales collections were made over thecourse of two years, covering the states of Rio de Janeiro and Minas Gerais, from500 to 2600m above the sea level. The Uredinales Biota is composed of 38 genera(32 teleomorphs and 6 anamorphs and 207 species, 178 of which were teleomorphicand 29 anamorphic. The genera Puccinia, Uromyces and Phakopsora contained ahigh number of species (58% combined. A hundred and ninety-two hosts belongingto 63 botanical families were recorded. The rust/host ratio for ten of the richestfamilies in number of species was 1:8. A high similarity (50% was found betweentwo altitudinal ranges. The results provide a strong additional argument for the needto preserve and continue studies in such areas

  7. Effects of climate and geochemistry on soil organic matter stabilization and greenhouse gas emissions along altitudinal transects in different mountain regions

    Science.gov (United States)

    Griepentrog, Marco; Bodé, Samuel; Boudin, Mathieu; Dercon, Gerd; Doetterl, Sebastian; Matulanya, Machibya; Msigwa, Anna; Vermeir, Pieter; Boeckx, Pascal

    2017-04-01

    Terrestrial ecosystems are strongly influenced by climate change and soils are key compartments of the global carbon (C) cycle in terms of their potential to store or release significant amounts of C. This study is part of the interregional IAEA Technical Cooperation Project ``Assessing the Impact of Climate Change and its Effects on Soil and Water Resources in Polar and Mountainous Regions (INT5153)'' aiming to improve the understanding of climate change impacts on soil organic carbon (SOC) in fragile polar and high mountainous ecosystems at local and global scale for their better management and conservation. The project includes 13 benchmark sites situated around the world. Here we present novel data from altitudinal transects of three different mountain regions (Mount Kilimanjaro, Tanzania; Mount Gongga, China; Cordillera Blanca, Peru). All altitudinal transects cover a wide range of natural ecosystems under different climates and soil geochemistry. Bulk soil samples (four field replicates per ecosystem) were subjected to a combination of aggregate and particle-size fractionation followed by organic C, total nitrogen, stable isotope (13C, 15N) and radiocarbon (14C) analyses of all fractions. Bulk soils were further characterized for their geochemistry (Na, K, Ca, Mg, Al, Fe, Mn, Si, P) and incubated for 63 days to assess greenhouse gas emissions (CO2, CH4, NO, N2O). Further, stable C isotopic signature of CO2 was measured to determine the isotopic signature of soil respiration (using Keeling plots) and to estimate potential respiration sources. The following four ecosystems were sampled at an altitudinal transect on the (wet) southern slopes of Mount Kilimanjaro: savannah (920m), lower montane rain forests with angiosperm trees (2020m), upper montane cloud forest with gymnosperm trees (2680m), subalpine heathlands (3660m). Both forests showed highest C contents followed by subalpine and savannah. The largest part of SOC was found in particulate organic matter

  8. How does glaucoma look?: patient perception of visual field loss.

    Science.gov (United States)

    Crabb, David P; Smith, Nicholas D; Glen, Fiona C; Burton, Robyn; Garway-Heath, David F

    2013-06-01

    To explore patient perception of vision loss in glaucoma and, specifically, to test the hypothesis that patients do not recognize their impairment as a black tunnel effect or as black patches in their field of view. Clinic-based cross-sectional study. Fifty patients (age range, 52-82 years) with visual acuity better than 20/30 and with a range of glaucomatous visual field (VF) defects in both eyes, excluding those with very advanced disease (perimetrically blind). Participants underwent monocular VF testing in both eyes using a Humphrey Field Analyzer (HFA; Carl Zeiss Meditec, Dublin, CA; 24-2 Swedish interactive threshold algorithm standard tests) and other tests of visual function. Participants took part in a recorded interview during which they were asked if they were aware of their VF loss; if so, there were encouraged to describe it in their own words. Participants were shown 6 images modified in a variety of ways on a computer monitor and were asked to select the image that most closely represented their perception of their VF loss. Forced choice of an image best representing glaucomatous vision impairment. Participants had a range of VF defect severity: average HFA mean deviation was -8.7 dB (standard deviation [SD], 5.8 dB) and -10.5 dB (SD, 7.1 dB) in the right and left eyes, respectively. Thirteen patients (26%; 95% confidence interval [CI], 15%-40%) reported being completely unaware of their vision loss. None of the patients chose the images with a distinct black tunnel effect or black patches. Only 2 patients (4%; 95% CI, 0%-14%) chose the image with a tunnel effect with blurred edges. An image depicting blurred patches and another with missing patches was chosen by 54% (95% CI, 39%-68%) and 16% (95% CI, 7%-29%) of the patients, respectively. Content analysis of the transcripts from the recorded interviews indicated a frequent use of descriptors of visual symptoms associated with reported blur and missing features. Patients with glaucoma do not perceive

  9. Pulsed field losses in metal-filled superconducting multifilamentary braids

    International Nuclear Information System (INIS)

    McInturff, A.D.; Dahl, P.F.; Sampson, W.B.

    1972-01-01

    Work on the application of metallic filters to insulate and bond individual multifilamentary wires into a fully transposed conductor is summarized. As has been reported in earlier papers, conductors of this type have performed excellently in low-frequency pulsed magnets, but become coupled at relatively low values of db/dt, leading to high potential losses. Data are presented on metallic and intermetallic insulated braids showing excellent performance and exhibiting losses comparable to those of organically insulated braid for rise times less than 10 kG/s. These conductors are also able to achieve 90 percent of short sample critical current at db/dt 200 kG/s, although their losses are significantly higher at these high rates of field change

  10. Apparatus to examine pulsed parallel field losses in large conductors

    International Nuclear Information System (INIS)

    Miller, J.R.; Shen, S.S.

    1977-01-01

    Conductors in tokamak toroidal field coils will be exposed to pulsed fields both parallel and perpendicular to the current direction. These conductors will likely be quite high capacity (10 to 20 kA) and therefore probably will be built up out of smaller units. We have previously published measurements of losses in conductors exposed to a pulsed parallel field, but those experiments necessarily used monolithic conductors of relatively small cross section because the pulse coil, a torus that surrounded the test conductor, was itself small. Here we describe an apparatus that is conceptually similar but has been scaled up to accept conductors of much larger cross section and current capacity. The apparatus consists basically of a superconducting torus that contains a movable spool to allow test samples to be wound inside without unwinding the torus. Details of apparatus design and capabilities are described and preliminary results from tests of the apparatus and from loss measurements using it are reported

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

    International Nuclear Information System (INIS)

    Guasp, J.

    1997-01-01

    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)

  12. Parallel altitudinal clines reveal trends in adaptive evolution of genome size in Zea mays

    Science.gov (United States)

    Berg, Jeremy J.; Birchler, James A.; Grote, Mark N.; Lorant, Anne; Quezada, Juvenal

    2018-01-01

    While the vast majority of genome size variation in plants is due to differences in repetitive sequence, we know little about how selection acts on repeat content in natural populations. Here we investigate parallel changes in intraspecific genome size and repeat content of domesticated maize (Zea mays) landraces and their wild relative teosinte across altitudinal gradients in Mesoamerica and South America. We combine genotyping, low coverage whole-genome sequence data, and flow cytometry to test for evidence of selection on genome size and individual repeat abundance. We find that population structure alone cannot explain the observed variation, implying that clinal patterns of genome size are maintained by natural selection. Our modeling additionally provides evidence of selection on individual heterochromatic knob repeats, likely due to their large individual contribution to genome size. To better understand the phenotypes driving selection on genome size, we conducted a growth chamber experiment using a population of highland teosinte exhibiting extensive variation in genome size. We find weak support for a positive correlation between genome size and cell size, but stronger support for a negative correlation between genome size and the rate of cell production. Reanalyzing published data of cell counts in maize shoot apical meristems, we then identify a negative correlation between cell production rate and flowering time. Together, our data suggest a model in which variation in genome size is driven by natural selection on flowering time across altitudinal clines, connecting intraspecific variation in repetitive sequence to important differences in adaptive phenotypes. PMID:29746459

  13. A proximal retarding field analyzer for scanning probe energy loss spectroscopy

    Science.gov (United States)

    Bauer, Karl; Murphy, Shane; Palmer, Richard E.

    2017-03-01

    A compact proximal retarding field analyzer for scanning probe energy loss spectroscopy measurements is described. Using the scanning tunneling microscope (STM) tip as a field emission (FE) electron source in conjunction with this analyzer, which is placed at a glancing angle to the surface plane, FE sample current and electron reflectivity imaging may be performed simultaneously. This is demonstrated in measurements of Ag nanostructures prepared on graphite by electron-beam lithography, where a material contrast of 13% is observed, with a lateral resolution of 25 nm, between the silver and graphite in electron reflectivity images. Topological contrast mechanisms such as edge enhancement and shadowing are also observed, giving rise to additional features in the electron reflectivity images. The same instrument configuration has been used to measure electron energy loss spectra on bare graphite, where the zero loss peak, π band plasmon loss peak and secondary electron peaks are observed. Using this simple and compact analyzer an STM, with sufficient open access to the tip-sample junction, may easily be augmented to provide simultaneous elemental and topographic mapping, supplementing STM image measurements with FE sample current and electron reflectivity images, as well as electron energy loss spectroscopy measurements, in the same instrument.

  14. To answer or not to answer? A field test of loss aversion

    OpenAIRE

    Michał Krawczyk

    2011-01-01

    This study is a field experiment on loss aversion. The framing of scoring rules was differentiated in two exams at the University of Warsaw, with only half the students facing explicit penalty points in the case of giving an incorrect answer. Loss aversion predicts that less risk will be taken (less questions will be answered) when losses are possible but in fact, no treatment effect was observed.

  15. Rotor Field Oriented Control with adaptive Iron Loss Compensation

    DEFF Research Database (Denmark)

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

    1999-01-01

    of the motor referenced to the rotor magnetizing current, and with the extension of an iron loss resistor added in parallel to the magnetizing inductance. The resistor estimator is based on the observation that the actual applied stator voltages deviates from the voltage estimated, when a motor is current......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...

  16. Seasonal and altitudinal variation in roe deer (Capreolus pygargus tianschanicus) diet on Jeju Island, South Korea

    OpenAIRE

    Adhikari, Pradeep; Park, Seon-Mi; Kim, Tae-Wook; Lee, Jun-Won; Kim, Ga-Ram; Han, Sang-Hyun; Oh, Hong-Shik

    2016-01-01

    In order to understand the feeding ecology and dietary differences of roe deer (Capreolus pygargus tianschanicus) in different seasons and altitudes, this study was carried out at three altitudinal sites (Songdang 250–270 m above sea level (ASL), Aradong 330–370 m ASL, Mt. Hallasan 1100 m ASL) on Jeju Island, South Korea. Altogether, 205 plants taxa of six categories of foods (forbs-climbers, graminoids, trees, shrubs, conifers, and ferns) were identified using morphological and molecular ana...

  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...... 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. Analysis of the altitudinal structure of Storm-enhanced density using Total Electron Content data of space-borne and ground-based GPS receivers

    Directory of Open Access Journals (Sweden)

    Yukari Goi

    2013-11-01

    Full Text Available The altitudinal structure of Storm-enhanced density (SED was studied using the Total Electron Content (TEC data of the GPS receiver on the Gravity Recovery and Climate Experiment (GRACE satellite and the ground-based GPS receivers. The GRACETEC-data are derived from the GPS receiver on the GRACE satellite. A SED is a high-electron density phenomenon that extends from the Equatorial Ionization Anomaly (EIA toward the north-west in the northern hemisphere during geomagnetic disturbed time. TwoSEDs were observed as TEC variations in the GRACE-TEC data and in the ground-GPS TEC data. The ground-GPS TEC data is the TEC data between the ground GPS receiver and the GPS satellites. The SED observed in the GRACE-TEC data appeared at higher latitudes than that in the ground-GPS TEC data. We concluded detected that the altitudinal structure of the SED would be different between at lower than at higher latitudes due to the effects of the eastward E×B drift.

  19. 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

  20. Bifurcation of radial electric field in tokamak edge plasmas due to ion orbit loss

    International Nuclear Information System (INIS)

    Wu, G.J.; Zhang, X.D.

    2015-01-01

    The ion orbit loss and the formation of radial electric field Er in tokamak edge region are calculated. The ion orbit loss generates a negative Er, which in turn affects the ion loss. As a result, Er can saturates at either a low or a high value, depending on the plasma parameters. When the ion temperature in the plasma edge is higher than a threshold a self-sustaining growth in both the ion loss and Er is found, leading to a high saturation value of Er in the milliseconds time. This mechanism provides a possible explanation for the formation of the edge radial electric field during the L to H-mode transition observed in tokamak experiments. (author)

  1. The risk of pedestrian collisions with peripheral visual field loss

    OpenAIRE

    Peli, Eli; Apfelbaum, Henry; Berson, Eliot L.; Goldstein, Robert B.

    2016-01-01

    Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed...

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  3. Measurement of the permittivity and loss of high-loss materials using a Near-Field Scanning Microwave Microscope

    International Nuclear Information System (INIS)

    Gregory, A.P.; Blackburn, J.F.; Lees, K.; Clarke, R.N.; Hodgetts, T.E.; Hanham, S.M.; Klein, N.

    2016-01-01

    In this paper improvements to a Near-Field Scanning Microwave Microscope (NSMM) are presented that allow the loss of high loss dielectric materials to be measured accurately at microwave frequencies. This is demonstrated by measuring polar liquids (loss tangent tanδ≈1) for which traceable data is available. The instrument described uses a wire probe that is electromagnetically coupled to a resonant cavity. An optical beam deflection system is incorporated within the instrument to allow contact mode between samples and the probe tip to be obtained. Liquids are contained in a measurement cell with a window of ultrathin glass. The calibration process for the microscope, which is based on image-charge electrostatic models, has been adapted to use the Laplacian ‘complex frequency’. Measurements of the loss tangent of polar liquids that are consistent with reference data were obtained following calibration against single-crystal specimens that have very low loss. - Highlights: • Design of a microwave microscope with resolution on the micron scale. • Improved theory for obtaining permittivity and loss tangent of high loss materials. • Polar reference liquids are used as test samples. • Traceable measurements with accuracy approximately ±10% in ε′ and ±20% in tan δ.

  4. 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

  5. ZONIFICACIÓN ALTITUDINAL PROVISIONAL DE Abies religiosa EN UN ÁREA CERCANA A LA RESERVA DE LA BIÓSFERA DE LA MARIPOSA MONARCA, MICHOACÁN

    Directory of Open Access Journals (Sweden)

    Dante Castellanos-Acuña

    2014-01-01

    Full Text Available E l objetivo del presente trabajo fue determinar la existencia de diferenciación morfológica (como indicador de variación genética entre poblaciones de Abies religiosa , con la finalidad de delimitar una zonificación altitudinal para decidir el movimiento de semillas en los progra - mas de reforestación. Se recolectaron y analizaron morfológicamente ramas y conos de 11 in - dividuos de 15 poblaciones de A. religiosa en el cerro de San Andrés, municipio de Hidalgo, Michoacán (cercano a la Reserva de la Biósfera de la Mariposa Monarca, a lo largo de un transecto altitudinal (2,850-3,550 m, una población cada 50 m. La diferenciación morfológica significativa entre poblacio - nes se determinó a lo largo del gradiente altitudinal; las poblaciones de baja altitud tienen acículas más cortas y conos más largos que las poblaciones de elevada altitud. Se sugiere delimitar tres zonas altitu - dinales provisionales: 2,800 a 3,050; 3,050 a 3,300; y 3,300 a 3,550 m. Ignorando el cambio climático, se sugiere reforestar cada zona con planta originada de la semilla en la misma zona. Considerando el cambio climático, se sugiere realizar migración asistida altitudinalmente, plantando sitios en la zona inmediata superior a la zona donde la semilla se recolecte.

  6. 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).

  7. 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 * Himalaya n serow * Nepal * Midhills * Habitat fragmentation * Altitudinal gradient Subject RIV: EH - Ecology, Behaviour Impact factor: 1.535, year: 2012

  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......-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...... saturation. Further quantitative and long-term studies on survival and recruitment in populations and communities are needed to determine the importance of temperature and oxygen for altitudinal limits of aquatic insects....

  9. Variability of Measured Runoff and Soil Loss from Field Plots

    Directory of Open Access Journals (Sweden)

    F. Asadzadeh

    2016-02-01

    Full Text Available Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes. Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on

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

    International Nuclear Information System (INIS)

    Perkins, R. J.; Bell, R. E.; Bertelli, N.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; LeBlanc, B. P.; Kramer, G. J.; Maingi, R.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Scotti, F.; Taylor, G.; Wilson, J. R.; Ahn, J-W.; Gray, T. K.; Green, D. L.; McLean, A.

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, R. J.; Bell, R. E.; Bertelli, N.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; LeBlanc, B. P.; Kramer, G. J.; Maingi, R.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Scotti, F.; Taylor, G.; Wilson, J. R. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Ahn, J-W.; Gray, T. K.; Green, D. L.; McLean, A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); and others

    2014-02-12

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

  12. Losses in variable fields

    International Nuclear Information System (INIS)

    Bronca, G.; Fevrier, A.; Genevey, P.; Perot, J.

    1974-01-01

    After a recall of the theory of losses in type 11 superconductors and review of recent work on this topic, the characteristics of what should be an ideal conductor for a pulsed magnet are given. The requirements of pulsed magnets for high energy physics are reviewed and total losses for a 1000 GeV synchrotron estimated. Finally, recent results of prototypes are reported along with the projects of superconducting synchrotron accelerators through the world. (author)

  13. 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

  14. Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China

    Directory of Open Access Journals (Sweden)

    Minyi Huang

    2016-03-01

    Full Text Available Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G, building patch (B, mature patch (M and degenerate patch (D. To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1 Different species (or functional groups had distinct presence frequencies in the four different patch types along the altitudinal gradient; (2 Some species or functional groups (species groups sharing similar traits and responses to the environment only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3 Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former; (4 The maximum numbers of species and two diversity indices (D′ and H′ were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

  15. HPTLC detection of altitudinal variation of the potential antivenin stigmasterol in different populations of the tropical ethnic antidote Rauvolfia serpentina.

    Science.gov (United States)

    Dey, Abhijit; Pandey, Devendra Kumar

    2014-09-01

    To determine the altitudinal variation of stigmasterol, a potential antivenin, in roots from seven populations of Rauvolfia serpentina (L). Benth. ex Kurz. (Apocynaceae) (R. serpentina), an important herb found in Indian subcontinent which has long been used in the treatment of snakebite, blood pressure and schizophrenia. Altitudinal variation of stigmasterol content in R. serpentina roots was analyzed by high performance thin layer chromatography. Chromatography was performed on silica gel 60 F254 thin layer chromatography plates with benzene-acetone 86:14 (v/v) as mobile phase. Densitometric analysis was done at λ=366 nm after derivatization with vanillin-10% (v/v) sulphuric acid alcohol reagent. The method was validated for precision and recovery. The present experiment demonstrates a simple, rapid, precise and sensitive high performance thin layer chromatography protocol for qualitative and quantitative determination of stigmasterol from different populations of R. serpentina. Results demonstrated that in root samples stigmasterol was present at Rf value of 0.44. This investigation demonstrates that stigmasterol content in R. serpentina roots varies in different altitudes. Popular ethnomedicinal use of this herb against snakebite may be contributed by the occurrence of stigmasterol in its roots. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Gutiérrez-Fonseca, Pablo E; Springer, Monika

    2015-12-18

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

  17. 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...

  18. 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.

  19. Prediction of the diffuse-field transmission loss of interior natural-ventilation openings and silencers.

    Science.gov (United States)

    Bibby, Chris; Hodgson, Murray

    2017-01-01

    The work reported here, part of a study on the performance and optimal design of interior natural-ventilation openings and silencers ("ventilators"), discusses the prediction of the acoustical performance of such ventilators, and the factors that affect it. A wave-based numerical approach-the finite-element method (FEM)-is applied. The development of a FEM technique for the prediction of ventilator diffuse-field transmission loss is presented. Model convergence is studied with respect to mesh, frequency-sampling and diffuse-field convergence. The modeling technique is validated by way of predictions and the comparison of them to analytical and experimental results. The transmission-loss performance of crosstalk silencers of four shapes, and the factors that affect it, are predicted and discussed. Performance increases with flow-path length for all silencer types. Adding elbows significantly increases high-frequency transmission loss, but does not increase overall silencer performance which is controlled by low-to-mid-frequency transmission loss.

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

    Science.gov (United States)

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

    2017-04-01

    Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Central Africa, focussing on shifts in carbon allocation, forest structure, nutrient cycling and functional composition. The Ecuadorian transect has 16 plots (40 by 40 m) and ranges from 400 to 3000 m.a.s.l., and the Rwandan transect has 20 plots (40 by 40 m) from 1500 to 3000 m.a.s.l. All plots were inventoried and canopy, litter and soil were extensively sampled. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed altitudinal adaption mechanisms are. This could provide us with vital information of the ecological responses of both biomes to future global change scenarios. Additionally, comparison of nutrient shifts and trait-based functional composition allows us to compare the biogeochemical cycles of African and South-American tropical forests.

  1. Species richness of vascular plants, bryophytes, and lichens along an altitudinal gradient in western Norway

    Science.gov (United States)

    Grytnes, John Arvid; Heegaard, Einar; Ihlen, Per G.

    2006-05-01

    Species richness patterns of ground-dwelling vascular plants, bryophytes, and lichens were compared along an altitudinal gradient (310-1135 m a.s.l.), in western Norway. Total species richness peaked at intermediate altitudes, vascular plant species richness peaked immediately above the forest limit (at 600-700 m a.s.l.), bryophyte species richness had no statistically significant trend, whereas lichen richness increased from the lowest point and up to the forest limit, with no trend above. It is proposed that the pattern in vascular plant species richness is enhanced by an ecotone effect. Bryophyte species richness responds to local scale factors whereas the lichen species richness may be responding to the shading from the forest trees.

  2. VARIACIÓN ALTITUDINAL ENTRE ESPECIES Y PROCEDENCIAS DE Pinus pseudostrobus, P. devoniana y P. leiophylla. ENSAYO DE VIVERO

    Directory of Open Access Journals (Sweden)

    Dante Castellanos-Acuña

    2013-01-01

    Full Text Available Los bosques de pino-encino de la comunidad de Nuevo San Juan, Michoacán, están dominados por Pinus pseudostrobus, P. devoniana y P. leiophylla. Los patrones de variación genética de estas especies no se conocen lo suficiente, particularmente los de P. leiophylla, lo cual limita la creación de lineamientos para el movimiento de semillas y plántulas para reforestación y su adaptación al cambio climático. Las especies se recolectaron en cuatro o cinco procedencias a lo largo de un transecto altitudinal (1,650 a 2,500 m para el establecimiento de un ensayo en vivero, con el objetivo de cuantificar la variación genética entre y dentro de las especies. La altura de la planta (tres y cinco meses de edad fue significativamente diferente (P < 0.0001 entre especies. Entre procedencias hubo diferencias significativas para P. devoniana (P < 0.0001 y P. leiophylla (P = 0.0352. La especie P. devoniana mostró un pronunciado patrón de crecimiento asociado con la altitud de origen, donde las plantas con mayor crecimiento procedían de una menor altitud. Las poblaciones de P. leiophylla fueron diferentes sólo a los tres meses de edad, sin un patrón altitudinal estadísticamente significativo. No se encontraron diferencias significativas entre poblaciones de P. pseudostrobus.

  3. Weeds Cause Losses in Field Crops through Allelopathy

    Directory of Open Access Journals (Sweden)

    Ali ZOHAIB

    2016-03-01

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

  4. Does an Intrinsic Magnetic Field Inhibit or Enhance Planetary Ionosphere Outflow and Loss?

    Science.gov (United States)

    Strangeway, R. J.; Russell, C. T.; Luhmann, J. G.; Moore, T. E.; Foster, J. C.; Barabash, S. V.; Nilsson, H.

    2017-12-01

    A characteristic feature of the planets Earth, Venus and Mars is the observation of the outflow of ionospheric ions, most notably oxygen. The oxygen ion outflow is frequently assumed to be a proxy for the loss of water from the planetary atmosphere. In terms of global outflow rates for the Earth the rate varies from 1025 to 1026 s-1, depending on geomagnetic activity. For both Venus and Mars global rates of the order 5x1024 s-1 have been reported. Venus and Mars do not have a large-scale intrinsic magnetic field, and there are several pathways for atmospheric and ionospheric loss. At Mars, because of its low gravity, neutral oxygen can escape through dissociative recombination. At Venus only processes related to the solar wind interaction with the planet such as sputtering and direct scavenging of the ionosphere by the solar wind can result in oxygen escape. At the Earth the intrinsic magnetic field forms a barrier to the solar wind, but reconnection of the Earth's magnetic field with the Interplanetary Magnetic Field allows solar wind energy and momentum to be transferred into the magnetosphere, resulting in ionospheric outflows. Observations of oxygen ions at the dayside magnetopause suggest that at least some of these ions escape. In terms of the evolution of planetary atmospheres how the solar-wind driven escape rates vary for magnetized versus umagnetized planets is also not clear. An enhanced solar wind dynamic pressure will increase escape from the unmagnetized planets, but it may also result in enhanced reconnection at the Earth, increasing outflow and loss rates for the Earth as well. Continued improvement in our understanding of the different pathways for ionospheric and atmospheric loss will allow us to determine how effective an intrinsic planetary field is in preserving a planetary atmosphere, or if we have to look for other explanations as to why the atmospheres of Venus and Mars have evolved to their desiccated state.

  5. 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

  6. 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)

    1996-12-31

    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

  7. Diversity of bees and their floral resources at altitudinal areas in the Southern Espinhaço Range, Minas Gerais, Brazil.

    Science.gov (United States)

    Araújo, Vinícius A; Antonini, Yasmine; Araújo, Ana P A

    2006-01-01

    The Southern Espinhaço Range consists of large areas covered by quartzitic or metaliferous tropical altitudinal fields. The Espinhaço Range ecosystems are endangered by anthropic high impacts, particularly due to mining and urbanization. We conducted a one-year inventory of the bee flora and fauna at the quartzitic Ouro Branco Mountains and a two-year survey of the metaliferous Ouro Preto fields. The samples were collected twice a month, from 8:00 am to 5:00 pm. The bees (677) belonged to 91 species, five families. The family Apidae was the richest and most abundant, followed by the Halictidae and Megachilidae. The bees visited 46 flowering plant species; the most visited plants were the Asteraceae (n = 220), the Malpighiaceae (n = 95), the Melastomataceae (n = 94), the Fabaceae (n = 78), and the Solanaceae (n = 63). Diversity was higher in Ouro Branco (H = 1.47) than in Ouro Preto (H = 1.17). The low richness and abundance of bees in our research site when compared to other Brazilian "Cerrado" areas can be due to the high altitude, low temperature, and low availability of flowers we found. "Canga" and rupestrian areas house fauna and flora species that are rare and threatened by extinction. The southern Espinhaço areas can, therefore, be given the status of permanent biodiversity preservation area.

  8. Magnetic field structure influence on primary electron cusp losses for micro-scale discharges

    International Nuclear Information System (INIS)

    Dankongkakul, Ben; Araki, Samuel J.; Wirz, Richard E.

    2014-01-01

    An experimental effort was used to examine the primary electron loss behavior for micro-scale (≲3 cm diameter) discharges. The experiment uses an electron flood gun source and an axially aligned arrangement of ring-cusps to guide the electrons to a downstream point cusp. Measurements of the electron current collected at the point cusp show an unexpectedly complex loss pattern with azimuthally periodic structures. Additionally, in contrast to conventional theory for cusp losses, the overall radii of the measured collection areas are over an order of magnitude larger than the electron gyroradius. Comparing these results to Monte Carlo particle tracking simulations and a simplified analytical analysis shows that azimuthal asymmetries of the magnetic field far upstream of the collection surface can substantially affect the electron loss structure and overall loss area

  9. [Clinico-statistical study on availability of Esterman disability score for assessment of mobility difficulty in patients with visual field loss].

    Science.gov (United States)

    Yamagata, Yoshitaka; Terada, Yuko; Suzuki, Atsushi; Mimura, Osamu

    2010-01-01

    The visual efficiency scale currently adopted to determine the legal grade of visual disability associated with visual field loss in Japan is not appropriate for the evaluation of disability regarding daily living activities. We investigated whether Esterman disability score (EDS) is suitable for the assessment of mobility difficulty in patients with visual field loss. The correlation between the EDS calculated from Goldmann's kinetic visual field and the degree of subjective mobility difficulty determined by a questionnaire was investigated in 164 patients with visual field loss. The correlation between the EDS determined using a program built into the Humphrey field analyzer and that calculated from Goldmann's kinetic visual field was also investigated. The EDS based on the kinetic visual field was correlated well with the degree of subjective mobility difficulty, and the EDS measured using the Humphrey field analyzer could be estimated from the kinetic visual field-based EDS. Instead of the currently adopted visual efficiency scale, EDS should be employed for the assessment of mobility difficulty in patients with visual field loss, also to establish new judgment criteria concerning the visual field.

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

    Science.gov (United States)

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

    2016-04-01

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

  11. 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.

  12. Low field critical currents and ac losses of thin film niobium--tin superconductors

    International Nuclear Information System (INIS)

    Howard, R.E.

    1977-01-01

    The results of a study of the low field critical current and ac loss properties of niobium-tin thin films and layered composites fabricated by electron-beam coevaporation are presented. Particular emphasis is placed upon determining the suitability of this material for use as a conductor in a superconducting power transmission line. Chapter I contains a summary of this work and its major results together with an introduction to the scientific and engineering concepts associated with a superconducting power transmission line. Chapter II is a discussion of the physics of current transport and the associated loss mechanisms in a type-II superconductor. Chapter III gives the details of the electron-beam coevaporation technique developed to fabricate the samples for this study. Also discussed in this chapter are the effects of the evaporation conditions on the growth morphology of the niobium-tin films. Chapter IV presents the details of the experimental techniques developed to measure the ac loss and critical current in these samples as a function of temperature. Chapter V shows the dependence of the critical current of these films and composites on temperature, magnetic field, and on the number of artificially introduced pinning centers in the layered composites. Experimental results are also presented concerning the stability of these conductors against flux jumps. Chapter VI is a discussion of the ac losses in these samples. Detailed comparisons are made between the measured loss and the predictions of the critical state model

  13. Gamma rays from relativistic electrons undergoing Compton losses in isotropic photon fields

    International Nuclear Information System (INIS)

    Zdziarski, A.A.

    1989-01-01

    The kinetic equation describing Compton losses of relativistic electrons in an isotropic field of soft background photons is solved exactly including both continuous energy losses in the classical Thomson regime and catastrophic losses in the quantum Klein-Nishina regime. This extends the previous treatments of this problem, which assumed the validity of either one of these regimes alone. The problem is relevant to astrophysical sources containing relativistic electrons. Analytical solutions for the steady state electron and gamma-ray spectra in the case of power-law soft photons and monoenergetic and power-law electron injections are obtained. Numerical solutions are presented for monoenergetic, blackbody, and power-law soft photons. A comparison between the numerical and the available analytic solutions is made. 15 refs

  14. Can variation in risk of nest predation explain altitudinal migration in tropical birds?

    Science.gov (United States)

    Boyle, W Alice

    2008-03-01

    Migration is among the best studied of animal behaviors, yet few empirical studies have tested hypotheses explaining the ultimate causes of these cyclical annual movements. Fretwell's (1980) hypothesis predicts that if nest predation explains why many tropical birds migrate uphill to breed, then predation risk must be negatively associated with elevation. Data from 385 artificial nests spanning 2,740 m of elevation on the Atlantic slope of Costa Rica show an overall decline in predation with increasing elevation. However, nest predation risk was highest at intermediate elevations (500-650 m), not at lowest elevations. The proportion of nests depredated by different types of predators differed among elevations. These results imply that over half of the altitudinal migrant bird species in this region migrate to safer breeding areas than their non-breeding areas, suggesting that variation in nest predation risk could be an important benefit of uphill migrations of many species.

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

    CERN Document Server

    Krismanic, G; Baumgartinger, N

    2000-01-01

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

  16. Information loss in effective field theory: Entanglement and thermal entropies

    Science.gov (United States)

    Boyanovsky, Daniel

    2018-03-01

    Integrating out high energy degrees of freedom to yield a low energy effective field theory leads to a loss of information with a concomitant increase in entropy. We obtain the effective field theory of a light scalar field interacting with heavy fields after tracing out the heavy degrees of freedom from the time evolved density matrix. The initial density matrix describes the light field in its ground state and the heavy fields in equilibrium at a common temperature T . For T =0 , we obtain the reduced density matrix in a perturbative expansion; it reveals an emergent mixed state as a consequence of the entanglement between light and heavy fields. We obtain the effective action that determines the time evolution of the reduced density matrix for the light field in a nonperturbative Dyson resummation of one-loop correlations of the heavy fields. The Von-Neumann entanglement entropy associated with the reduced density matrix is obtained for the nonresonant and resonant cases in the asymptotic long time limit. In the nonresonant case the reduced density matrix displays an incipient thermalization albeit with a wave-vector, time and coupling dependent effective temperature as a consequence of memory of initial conditions. The entanglement entropy is time independent and is the thermal entropy for this effective, nonequilibrium temperature. In the resonant case the light field fully thermalizes with the heavy fields, the reduced density matrix loses memory of the initial conditions and the entanglement entropy becomes the thermal entropy of the light field. We discuss the relation between the entanglement entropy ultraviolet divergences and renormalization.

  17. 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.

  18. Forest filter effect versus cold trapping effect on the altitudinal distribution of PCBs: a case study of Mt. Gongga, eastern Tibetan Plateau.

    Science.gov (United States)

    Liu, Xin; Li, Jun; Zheng, Qian; Bing, Haijian; Zhang, Ruijie; Wang, Yan; Luo, Chunling; Liu, Xiang; Wu, Yanhong; Pan, Suhong; Zhang, Gan

    2014-12-16

    Mountains are observed to preferentially accumulate persistent organic pollutants (POPs) at higher altitude due to the cold condensation effect. Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls (PCBs) in different environmental matrices (soil, moss, and air) from nine elevations on the eastern slope of Mt. Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. The concentrations of 24 measured PCBs ranged from 41 to 510 pg/g dry weight (dw) (mean: 260 pg/g dw) in the O-horizon soil, 280 to 1200 pg/g dw (mean: 740 pg/g dw) in moss, and 33 to 60 pg/m(3) (mean: 47 pg/m(3)) in air. Soil organic carbon was a key determinant explaining 75% of the variation in concentration along the altitudinal gradient. Across all of the sampling sites, the average contribution of the forest filter effect (FFE) was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.

  19. Laser field effects on the transport phenomena: Energy loss and stopping power

    International Nuclear Information System (INIS)

    Torres Silva, H.; Sakanaka, P.H.

    1990-01-01

    The energy loss method has been applied to a large variety of transport problems in optics, solid-state and fusion research. In these papers, however, the transport equations were linearized, so there are no multiphoton interaction. On the other hand, Bivona et al. (1982) [2] have shown that, for a one-component plasma, the strong field effects would be only of academic interest. On the basis of the center of mass approach [3], a generalization of the energy loss rate which is in accordance with the recent results of Arista et al. (1989) [4] is obtained. (Author)

  20. Annual losses of weed seeds due to predation in organic cereal fields

    NARCIS (Netherlands)

    Westerman, P.R.; Wes, J.S.; Kropff, M.J.; Werf, van der W.

    2003-01-01

    1. Post-dispersal seed losses in annual arable weed species are poorly quantified, but may be of significance for natural population control, especially if they can be manipulated. We hypothesized that weed seed predation on the soil surface was significant, so we measured rates in the field to

  1. 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

  2. Altitudinal patterns and controls of trace metal distribution in soils of a remote high mountain, Southwest China.

    Science.gov (United States)

    Li, Rui; Bing, Haijian; Wu, Yanhong; Zhou, Jun; Xiang, Zhongxiang

    2018-02-01

    The aim of this study is to reveal the effects of regional human activity on trace metal accumulation in remote alpine ecosystems under long-distance atmospheric transport. Trace metals (Cd, Pb, and Zn) in soils of the Mt. Luoji, Southwest China, were investigated along a large altitudinal gradient [2200-3850 m above sea level (a.s.l.)] to elaborate the key factors controlling their distribution by Pb isotopic composition and statistical models. The concentrations of Cd, Pb, and Zn in the surface soils (O and A horizons) were relatively low at the altitudes of 3500-3700 m a.s.l. The enrichment factors of trace metals in the surface soils increased with altitude. After normalization for soil organic matter, the concentrations of Cd still increased with altitude, whereas those of Pb and Zn did not show a clear altitudinal trend. The effects of vegetation and cold trapping (CTE) (pollutant enrichment by decreasing temperature with increasing altitude) mainly determined the distribution of Cd and Pb in the O horizon, whereas CTE and bedrock weathering (BW) controlled that of Zn. In the A horizon, the distribution of Cd and Pb depended on the vegetation regulation, whereas that of Zn was mainly related to BW. Human activity, including ores mining and fossil fuels combustion, increased the trace metal deposition in the surface soils. The anthropogenic percentage of Cd, Pb, and Zn quantified 92.4, 67.8, and 42.9% in the O horizon, and 74.5, 33.9, and 24.9% in the A horizon, respectively. The anthropogenic metals deposited at the high altitudes of Mt. Luoji reflected the impact of long-range atmospheric transport on this remote alpine ecosystem from southern and southwestern regions.

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

    Science.gov (United States)

    Luo, Y; Widmer, A; Karrenberg, S

    2015-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Benicia Watteijne Ceron

    2009-09-01

    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 (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.

  5. Experimental Study of Soil Organic Matter Loss From Cultivated Field Plots In The Venezuelan Andes.

    Science.gov (United States)

    Bellanger, B.; Huon, S.; Velasquez, F.; Vallès, V.; Girardin A, C.; Mariotti, A. B.

    The question of discriminating sources of organic matter in suspended particles of stream flows can be addressed by using total organic carbon (TOC) concentration and stable isotope (13C, 15N) measurements when constant fluxes of organic matter supply can be assumed. However, little is known on the dynamics of organic matter release during soil erosion and on the temporal stability of its isotopic signature. In this study, we have monitored soil organic carbon loss and water runoff using natural rainfall events on three experimental field plots with different vegetation cover (bare soil, maize and coffee fields), set up on natural slopes of a tropical mountainous watershed in NW Venezuela (09°13'32'' ­ 09°10'00''N, 70°13'49'' ­ 70°18'34''W). Runoff and soil loss are markedly superior for the bare field plot than for the coffee field plot: by a factor 15 ­ 36, respectively, for the five-month experiment, and by a factor 30 ­ 120, respectively, during a single rainfall event experiment. Since runoff and soil organic matter loss are closely linked during most of the flow (at the time scales of this study), TOC concentration in suspended matter is constant. Furthermore, stable isotope compositions reflect those of top-soil organic matter from which they originate.

  6. Magnetic loss and B(H) behaviour of non-oriented electrical sheets under a trapezoidal exciting field

    Science.gov (United States)

    Kedous-Lebouc, A.; Errard, S.; Cornut, B.; Brissonneau, P.

    1994-05-01

    The excess loss and hysteresis response of electrical steel are measured and discussed in the case of trapezoidal field excitation similar to the current provided by a current commutation supply of a self-synchronous rotating machine. Three industrial non-oriented SiFe samples of different magnetic grades and thicknesses are tested using an automatic Epstein frame equipment. The losses and the unusual observed B( H) loops are analysed in terms of the rate of change of the field, the diffusion of the induction inside the sheet and by the calculation of the theoretical hysteresis cycles due to the eddy currents.

  7. Losses of neutral injected fast ions due to adiabaticity breaking processes in a field-reversed configuration

    International Nuclear Information System (INIS)

    Takahashi, Toshiki; Inoue, Koji; Ishizuka, Takashi; Kondoh, Yoshiomi; Iwasawa, Naotaka

    2004-02-01

    Losses of neutral beam (NB) injected fast ions from the confinement region of a Field-Reversed Configuration (FRC) with a strong magnetic mirror are numerically analyzed for parameters relevant to NB injection experiments on the FIX (FRC injection experiment) device [T. Asai et al., Phys. Plasmas 7, 2294 (2000)]. Ionization processes of beam particles are calculated by the Monte Carlo method. The confinement of beam ions is discussed with the concept of accessible regions that restrict the ion excursion and are determined from two constants of motion, the kinetic energy and canonical angular momentum, in the case of an axisymmetric and a steady state FRC without an electrostatic field. From the calculation of the accessible regions, it is found that all the fast ions suffer from the orbit loss on the wall surface and/or the end loss. Single particle orbits are also calculated to find a difference of confinement properties from the results by employing the accessible regions. The magnetic moment is observed to show non-adiabatic motions of the beam ions, which cause a gradual orbit loss on the wall even in a case that a strong magnetic mirror is applied. The results show that the correlation of the magnetic moment disappears as the fast ions experience the density gradient around the separatrix surface and the field-null points. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

  9. Scanning laser polarimetry, but not optical coherence tomography predicts permanent visual field loss in acute nonarteritic anterior ischemic optic neuropathy.

    Science.gov (United States)

    Kupersmith, Mark J; Anderson, Susan; Durbin, Mary; Kardon, Randy

    2013-08-15

    Scanning laser polarimetry (SLP) reveals abnormal retardance of birefringence in locations of the edematous peripapillary retinal nerve fiber layer (RNFL), which appear thickened by optical coherence tomography (OCT), in nonarteritic anterior ischemic optic neuropathy (NAION). We hypothesize initial sector SLP RNFL abnormalities will correlate with long-term regional visual field loss due to ischemic injury. We prospectively performed automated perimetry, SLP, and high definition OCT (HD-OCT) of the RNFL in 25 eyes with acute NAION. We grouped visual field threshold and RNFL values into Garway-Heath inferior/superior disc sectors and corresponding superior/inferior field regions. We compared sector SLP RNFL thickness with corresponding visual field values at presentation and at >3 months. At presentation, 12 eyes had superior sector SLP reduction, 11 of which had inferior field loss. Six eyes, all with superior field loss, had inferior sector SLP reduction. No eyes had reduced OCT-derived RNFL acutely. Eyes with abnormal field regions had corresponding SLP sectors thinner (P = 0.003) than for sectors with normal field regions. During the acute phase, the SLP-derived sector correlated with presentation (r = 0.59, P = 0.02) and with >3-month after presentation (r = 0.44, P = 0.02) corresponding superior and inferior field thresholds. Abnormal RNFL birefringence occurs in sectors corresponding to regional visual field loss during acute NAION when OCT-derived RNFL shows thickening. Since the visual field deficits show no significant recovery, SLP can be an early marker for axonal injury, which may be used to assess recovery potential at RNFL locations with respect to new treatments for acute NAION.

  10. Iron Loss Prediction Using Modified IEM-Formula during the Field Weakening for Permanent Magnet Synchronous Machines

    Directory of Open Access Journals (Sweden)

    Pedram Asef

    2017-12-01

    Full Text Available During field weakening operation time (FWOT, the total iron loss rises and affects the accuracy of loss prediction and efficiency, especially if a large range of FWOT exists due to a large voltage drop that was rooted from the resistance of the used material. Iron loss prediction is widely employed in investigations for a fast electrical machine analysis using 2D finite element analysis (FEA. This paper proposes harmonic loss analytically by a steady-state equivalent circuit with a novel procedure. Consideration of skin effects and iron saturation are utilized in order to examine the accuracy through the relative error distribution in the frequency domain of each model from 50 to 700 Hz. Additionally, this comparative study presents a torque-frequency-field density calculation over each single term of the modified institute of electrical machines formula (IEM-Formula. The proposed analytical calculation is performed using 2D FEA for a classic and modified IEM-Formula along with experimental verifications on a surface-mounted permanent magnet synchronous generator (PMSG for a wind generation application.

  11. Biomass and selected ecological factors of epiphytic bryophyte along altitudinal gradients in Southern Thailand

    Directory of Open Access Journals (Sweden)

    Sahut Chantanaorrapint

    2011-12-01

    Full Text Available Biomass of epiphytic bryophytes was investigated along three altitudinal transects in southern Thailand: TarutaoNational Park (25-700 m, Khao Nan National Park (400-1,300 m, and Khao Luang National Park (400-1,500 m. The dry weightof epiphytic bryophytes per surface area increased from 1.15 g/m2 in the lowland to a maximum 199 g/m2 at the lower montaneforests. The estimation of dry weight per hectare increased along transect from 2.4 to 620 kg. The water storing capacity ofepiphytic bryophytes was about 1.2 to 2.4 times as dry weight and was generally higher in the lower montane forest (up to1,500 l/ha than in the lowland forests. The bark pH of host trees range between 3.19 and 6.84, and show negative correlationwith the altitude (r=-0.635, p<0.05. Air temperature gradually decreases with the increasing altitude ca 0.6°C per 100 m elevation.

  12. Phyllostomidae assemblage (Chiroptera: Mammalia in altitudinal forests at the Parque Estadual do Ibitipoca, Southeast of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo M. Mello

    Full Text Available ABSTRACT Many studies have demonstrated the ecological relevance and great biodiversity of bats in Brazil. However, mountainous areas have been disproportionately less sampled, mainly in the Southeast. The aim of this study was to identify and compare the richness and diversity of Phyllostomidae, the most diverse bat family, in different forest types in Parque Estadual do Ibitipoca, trying to understand the causes of possible differences. The Parque Estadual do Ibitipoca is inserted in the Serra da Mantiqueira's domain, in an Atlantic Forest region known as "Zona da Mata", state of Minas Gerais, with an altitudinal range between 1200-1784 meters. The study was conducted in two forest types, classified as "Nanofloresta Nebular" and "Floresta Nebular", whose respective data on richness and diversity were compared. The bats were captured with 8-10 mist nets for 14 months (April 2011 to May 2012 and four nights per month totaling 62,171.25 m2h of capture effort. A total of 392 captures (12 species belonging to the Phyllostomidae family were obtained. The most abundant species were Sturnira lilium (59.9%, Platyrrhinus lineatus (11.3%, Artibeus lituratus (8.7% and Carollia perspicillata (7.6%. The two sampled areas presented differences in bat richness, diversity and species composition, and this difference was predominantly influenced by S. lilium. It is likely that the observed difference in the assembly of bats between the two study sites depends on the variation in floristic composition. The records of A. lituratus and P. lineatus in a few months of the year and close to Ficus mexiae bearing ripe fruits suggests that at least these species move to the park for a few periods of the year in search of food resources, possibly moving through the altitudinal landscapes.

  13. 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.

  14. Performance of an iPad Application to Detect Moderate and Advanced Visual Field Loss in Nepal.

    Science.gov (United States)

    Johnson, Chris A; Thapa, Suman; George Kong, Yu Xiang; Robin, Alan L

    2017-10-01

    To evaluate the accuracy and efficiency of Visual Fields Easy (VFE), a free iPad app, for performing suprathreshold perimetric screening. Prospective, cross-sectional validation study. We performed screening visual fields using a calibrated iPad 2 with the VFE application on 206 subjects (411 eyes): 210 normal (NL), 183 glaucoma (GL), and 18 diabetic retinopathy (DR) at Tilganga Institute of Ophthalmology, Kathmandu, Nepal. We correlated the results with a Humphrey Field Analyzer using 24-2 SITA Standard tests on 373 of these eyes (198 NL, 160 GL, 15 DR). The number of missed locations on the VFE correlated with mean deviation (MD, r = 0.79), pattern standard deviation (PSD, r = 0.60), and number of locations that were worse than the 95% confidence limits for total deviation (r = 0.51) and pattern deviation (r = 0.68) using SITA Standard. iPad suprathreshold perimetry was able to detect most visual field deficits with moderate (MD of -6 to -12 dB) and advanced (MD worse than -12 dB) loss, but had greater difficulty in detecting early (MD better than -6 dB) loss, primarily owing to an elevated false-positive response rate. The average time to perform the Visual Fields Easy test was 3 minutes, 18 seconds (standard deviation = 16.88 seconds). The Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss. Improvements are currently underway to monitor eye and head tracking during testing, reduce testing time, improve performance, and eliminate the need to touch the video screen surface. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Zhang Lei

    2015-01-01

    Full Text Available 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 of eddy-current losses in prototype PMSM are analyzed by the finite element analysis (FEA software. The contents researched in the paper have practical reference values for design and reliability analysis of PMSMs.

  16. Contrasting growth forecasts across the geographical range of Scots pine due to altitudinal and latitudinal differences in climatic sensitivity.

    Science.gov (United States)

    Matías, Luis; Linares, Juan C; Sánchez-Miranda, Ángela; Jump, Alistair S

    2017-10-01

    Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of a species' geographical distribution, where differences in growth or population dynamics may result in range expansions or contractions. Understanding population responses to different climatic drivers along wide latitudinal and altitudinal gradients is necessary in order to gain a better understanding of plant responses to ongoing increases in global temperature and drought severity. We selected Scots pine (Pinus sylvestris L.) as a model species to explore growth responses to climatic variability (seasonal temperature and precipitation) over the last century through dendrochronological methods. We developed linear models based on age, climate and previous growth to forecast growth trends up to year 2100 using climatic predictions. Populations were located at the treeline across a latitudinal gradient covering the northern, central and southernmost populations and across an altitudinal gradient at the southern edge of the distribution (treeline, medium and lower elevations). Radial growth was maximal at medium altitude and treeline of the southernmost populations. Temperature was the main factor controlling growth variability along the gradients, although the timing and strength of climatic variables affecting growth shifted with latitude and altitude. Predictive models forecast a general increase in Scots pine growth at treeline across the latitudinal distribution, with southern populations increasing growth up to year 2050, when it stabilizes. The highest responsiveness appeared at central latitude, and moderate growth increase is projected at the northern limit. Contrastingly, the model forecasted growth declines at lowland-southern populations, suggesting an upslope range displacement over the coming decades. Our results give insight into the geographical responses of tree species to climate change

  17. DISTRIBUIÇÃO E RIQUEZA DE ESPÉCIES ARBÓREAS RARAS EM FRAGMENTOS DE FLORESTA OMBRÓFILA MISTA AO LONGO DE UM GRADIENTE ALTITUDINAL, EM SANTA CATARINA

    Directory of Open Access Journals (Sweden)

    Tiago de Souza Ferreira

    2015-06-01

    Full Text Available RESUMOEste estudo teve por objetivo analisar como a distribuição e riqueza de espécies raras em fragmentos de Floresta Ombrófila Mista ocorrem ao longo de um gradiente altitudinal. Para isso, espécies arbóreas (diâmetro à altura do peito > 5 cm foram amostradas em 10 fragmentos florestais localizados em diferentes pisos altitudinais do Planalto Sul-Catarinense, em uma área total de 10 ha. As espécies que apresentaram número de indivíduos igual ou inferior a 2 em pelo menos um fragmento foram classificadas como raras. A distribuição das espécies foi verificada por meio de dendrograma construído a partir do índice de distância florística de Jaccard e do algoritmo de agrupamento UPGMA. A riqueza total de espécies por fragmento e o número de espécies raras foram comparados entre as subformações montana e alto-montana, por meio do teste de Mann-Whitney (U. As relações entre altitude e os valores de riqueza total e número de espécies raras em cada fragmento foram determinadas por regressões lineares simples. Os resultados indicaram a formação de dois grandes grupos de espécies raras em função do piso altitudinal. Apesar de a riqueza total das comunidades reduzir com o aumento da altitude, o número de espécies raras não apresentou alterações significativas. Conclui-se que na região do Planalto Sul-Catarinense os fragmentos de Floresta Ombrófila Mista apresentam diferentes conjunto de espécies arbóreas raras de acordo com a altitude e que a diminuição da riqueza das comunidades com o aumento do piso altitudinal não é acompanhada pela redução do número de espécies raras.

  18. Characteristics of Phosphorus Runoff Losses from Typical Paddy Fields in Guangdong Province, China

    Directory of Open Access Journals (Sweden)

    NING Jian-feng

    2018-03-01

    Full Text Available Three experimental paddy fields located in the city of Zengcheng, Qingyuan and Gaozhou in Guangdong Province were selected to monitor the runoff losses of phosphorus from the year of 2008 to 2012. The results showed that runoff event in paddy field occurred mainly in the early rice season. The runoff concentration of total phosphorus(TP under conventional fertilization treatment was in the range of 0.02~1.56 mg·L-1. It was recorded that TP concentration in 11%~18% of the total runoff samples exceeded the grade Ⅴ of the national surface water environmental quality(0.4 mg·L-1. Peak concentration of different phosphorus forms[TP, dissolved total P(DTP and particulate P(PP] were observed within 14 days after fertilization, which indicated the high environmental pollution risk of phosphorus during this period. Application of phosphorus fertilizer increased runoff load of DTP in paddy field and showed no effect on that of PP and TP. The annual runoff loads of 0.63~4.05, 0.33~2.91 kg·hm-2 and 1.10~6.68 kg·hm-2 for DTP, PP and TP, respectively, were recorded under conventional fertilizer model. Runoff load of phosphorus exhibited wide spatial and temporal variation during experimental period. Runoff coefficient of 0.06%~6.81% of phosphorus was recorded. It was observed that DTP dominated the phosphorus runoff load. Phosphorus runoff losses from paddy field was affected by a variety of natural and human factors, and fertilization, precipitation and runoff volume were identified as the main factors.

  19. From frugivore to folivore: Altitudinal variations in the diet and feeding ecology of the Bioko Island drill (Mandrillus leucophaeus poensis).

    Science.gov (United States)

    Owens, Jacob R; Honarvar, Shaya; Nessel, Mark; Hearn, Gail W

    2015-12-01

    Variation in the quality and availability of food resources can greatly influence the ecology, behavior, and conservation of wild primates. We studied the influence of altitudinal differences in resource availability on diet in wild drill monkeys (Mandrillus leucophaeus poensis) on Bioko Island, Equatorial Guinea. We compared fecal samples (n = 234) collected across three consecutive dry seasons for drills living in lowland (0-300 m asl) forest with nearby (18 km distance) drills living in montane forest (500-1000 m asl) in the Gran Caldera Southern Highlands Scientific Reserve. Lowland forest drills had a frugivorous diet very similar to that reported from studies on nearby mainland drills (M. l. leucophaeus) and mandrills (M. sphinx), with fruits comprising 90% of their dried fecal samples. However drills living in montane forest had a more folivorous diet, with herbaceous pith, leaves and fungi comprising 74% of their dried fecal samples and fruit becoming a minor component (24%). Furthermore, a dietary preference index indicated that the differences in the proportion of fruit and fibrous vegetation in the diets of lowland compared to montane drills was not simply a result of relative availability. Montane drills were actively consuming a higher mass of the available fruits and fibrous vegetation, a condition reflected in the greater mass of their fresh feces. Our results demonstrate the unexpected flexibility and complexity of dietary choices of this endangered species in two adjacent habitat types, a comparison of considerable importance for many other limited-range species faced with habitat loss and climate change. © 2015 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2016-01-01

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

  1. Objective Analysis of Performance of Activities of Daily Living in People With Central Field Loss.

    Science.gov (United States)

    Pardhan, Shahina; Latham, Keziah; Tabrett, Daryl; Timmis, Matthew A

    2015-11-01

    People with central visual field loss (CFL) adopt various strategies to complete activities of daily living (ADL). Using objective movement analysis, we compared how three ADLs were completed by people with CFL compared with age-matched, visually healthy individuals. Fourteen participants with CFL (age 81 ± 10 years) and 10 age-matched, visually healthy (age 75 ± 5 years) participated. Three ADLs were assessed: pick up food from a plate, pour liquid from a bottle, and insert a key in a lock. Participants with CFL completed each ADL habitually (as they would in their home). Data were compared with visually healthy participants who were asked to complete the tasks as they would normally, but under specified experimental conditions. Movement kinematics were compared using three-dimension motion analysis (Vicon). Visual functions (distance and near acuities, contrast sensitivity, visual fields) were recorded. All CFL participants were able to complete each ADL. However, participants with CFL demonstrated significantly (P approach. Various kinematic indices correlated significantly to visual function parameters including visual acuity and midperipheral visual field loss.

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

    International Nuclear Information System (INIS)

    Iijima, Y.; Hosaka, M.; Sadakata, N.; Saitoh, T.; Kohno, O.; Takeda, K.

    1997-01-01

    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 J c sample, and agreed well with Norris close-quote equation for thin strip conductors. However, the low J c 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

  3. The measurement of power losses at high magnetic field densities or at small cross-section of test specimen using the averaging

    CERN Document Server

    Gorican, V; Hamler, A; Nakata, T

    2000-01-01

    It is difficult to achieve sufficient accuracy of power loss measurement at high magnetic field densities where the magnetic field strength gets more and more distorted, or in cases where the influence of noise increases (small specimen cross section). The influence of averaging on the accuracy of power loss measurement was studied on the cast amorphous magnetic material Metglas 2605-TCA. The results show that the accuracy of power loss measurements can be improved by using the averaging of data acquisition points.

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

    International Nuclear Information System (INIS)

    Candiani, A.; Argyros, A.; Leon-Saval, S. G.; Lwin, R.; Selleri, S.; Pissadakis, S.

    2014-01-01

    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

  5. The risk of pedestrian collisions with peripheral visual field loss.

    Science.gov (United States)

    Peli, Eli; Apfelbaum, Henry; Berson, Eliot L; Goldstein, Robert B

    2016-12-01

    Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed to be moving in all directions with equal probability within a reasonable range of walking speeds. The risk density was found to be highly anisotropic. It peaked at ≈45° eccentricity. Increasing pedestrian speed range shifted the risk to higher eccentricities. The risk density is independent of time to collision. The model results were compared to the binocular residual peripheral island locations of 42 patients with forms of retinitis pigmentosa. The natural residual island prevalence also peaked nasally at about 45° but temporally at about 75°. This asymmetry resulted in a complementary coverage of the binocular field of view. Natural residual binocular island eccentricities seem well matched to the collision-risk density function, optimizing detection of other walking pedestrians (nasally) and of faster hazards (temporally). Field expansion prism devices will be most effective if they can create artificial peripheral islands at about 45° eccentricities. The collision risk and residual island findings raise interesting questions about normal visual development.

  6. 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.; hide

    2016-01-01

    Recent results from the MAVEN Langmuir Probe and Waves (LPW) instrument suggest higher than predicted electron temperatures (T sub e) in Mars dayside ionosphere above approx. 180 km in altitude. Correspondingly, measurements from Neutral Gas and Ion Mass Spectrometer (NGIMS) indicate significant abundances of O2+ up to approx. 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 T(sub e) (which results from electron heating) and ion heating on ion outflow and loss. Numerical solutions show that plasma processes including ion heating and higher T(sub e) may greatly increase O2+ loss at Mars. In particular, enhanced T(sub e) in Mars ionosphere just above the exobase creates a substantial ambipolar electric field with a potential (e) of several k(sub b)T(sub e), 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.

  7. 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...... 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...

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

    Science.gov (United States)

    Green, David J; Whitehorne, Ivy B J; Middleton, Holly A; Morrissey, Christy A

    2015-01-01

    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.

  9. 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.

  10. Prior rates of visual field loss and lifetime risk of blindness in glaucomatous patients undergoing trabeculectomy.

    Science.gov (United States)

    Foulsham, W S; Fu, L; Tatham, A J

    2015-10-01

    Trend-based analyses examining rates of visual field (VF) loss in glaucoma are useful for predicting risk of vision-related morbidity. Although patients with faster losses are likely to require treatment escalation, little is known about rates that might trigger a decision to intervene surgically. The aims of this study were to investigate prior rates of VF loss in patients attending for trabeculectomy and to estimate, in the absence of surgical intervention, lifetime risk of visual impairment, and blindness. A retrospective analysis of 117 eyes of 86 consecutive patients with glaucoma attending for trabeculectomy, including 53 patients referred from general ophthalmology clinics and 33 patients from specialist glaucoma clinics. Rates of change in standard automated perimetry mean deviation were examined using linear regression and random coefficient models. Risk of lifetime visual impairment and blindness was calculated using life expectancy data. Mean age at surgery was 71.0±9.7 years. Patients were followed for 10.7±7.5 years prior to surgery with an average of seven useable fields per eye. On average patients referred from general clinics lost 1.04 dB/year compared with 0.77 dB/year in those referred from glaucoma clinics (P=0.070). Patients referred from general clinics had more medication changes prior to surgery (3.4 and 2.6 changes, respectively; P=0.004). Given Scottish life expectancy data, untreated, 61 eyes (52%) would have passed the threshold for visual impairment, whereas 40 (34%) would have passed the threshold demarcating blindness. Patients attending for trabeculectomy had faster average rates of field loss prior to surgery than published values for the general glaucoma population with over one-third of eyes studied predicted to have become blind without intervention. Those managed by glaucoma specialists had fewer changes in medication and tended to slower rates of VF loss, although the latter did not reach statistical significance.

  11. Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Patel, Sonal G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Falcon, Ross Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Cartwright, Keith [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Kiefer, Mark L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Cuneo, Michael E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Maron, Yitzhak [Weizmann Inst. of Science, Rehovot (Israel)

    2017-11-01

    This LDRD investigated plasma formation, field strength, and current loss in pulsed power diodes. In particular the Self-Magnetic Pinch (SMP) e-beam diode was studied on the RITS-6 accelerator. Magnetic fields of a few Tesla and electric fields of several MV/cm were measured using visible spectroscopy techniques. The magnetic field measurements were then used to determine the current distribution in the diode. This distribution showed that significant beam current extends radially beyond the few millimeter x-ray focal spot diameter. Additionally, shielding of the magnetic field due to dense electrode surface plasmas was observed, quantified, and found to be consistent with the calculated Spitzer resistivity. In addition to the work on RITS, measurements were also made on the Z-machine looking to quantify plasmas within the power flow regions. Measurements were taken in the post-hole convolute and final feed gap regions on Z. Dopants were applied to power flow surfaces and measured spectroscopically. These measurements gave species and density/temperature estimates. Preliminary B-field measurements in the load region were attempted as well. Finally, simulation work using the EMPHASIS, electromagnetic particle in cell code, was conducted using the Z MITL conditions. The purpose of these simulations was to investigate several surface plasma generations models under Z conditions for comparison with experimental data.

  12. Fine structures on zero-field steps in low-loss Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Monaco, Roberto; Barbara, Paola; Mygind, Jesper

    1993-01-01

    The first zero-field step in the current-voltage characteristic of intermediate-length, high-quality, low-loss Nb/Al-AlOx/Nb Josephson tunnel junctions has been carefully investigated as a function of temperature. When decreasing the temperature, a number of structures develop in the form...... of regular and slightly hysteretic steps whose voltage position depends on the junction temperature and length. This phenomenon is interesting for the study of nonlinear dynamics and for application of long Josephson tunnel junctions as microwave and millimeter-wavelength oscillators....

  13. Glaucoma Severity and Participation in Diverse Social Roles: Does Visual Field Loss Matter?

    Science.gov (United States)

    Yang, Yelin; Trope, Graham E; Buys, Yvonne M; Badley, Elizabeth M; Gignac, Monique A M; Shen, Carl; Jin, Ya-Ping

    2016-07-01

    To assess the association between glaucoma severity and participation in diverse social roles. Cross-sectional survey. Individuals with glaucoma, 50+, with visual acuity in the better eye >20/50 were enrolled. They were classified into 3 groups based on visual field loss in the better eye: mild [mean deviation (MD)>-6 dB], moderate (MD, -6 to -12 dB), and severe (MDSocial Role Participation Questionnaire assessed respondents' perceptions of the importance, difficulty, and satisfaction with participation in 11 social role domains (eg, community events, travel). Differences between groups were examined using multivariate linear regression analyses. A total of 118 participants (52% female) were included: 60 mild, 29 moderate, and 29 severe. All social role domains were rated as important by all participants except for education and employment. Women (Psocial activities. Compared with those with mild glaucoma, individuals with severe glaucoma reported significantly more difficulty participating in community/religious/cultural events (Psocial events (P=0.04). Participation in diverse social roles is valued by individuals with glaucoma. Severe visual field loss impedes involvement in and satisfaction with activities in community/religious/cultural events, travelling, and relationships with family members. Appropriate community and targeted interventions are needed to allow people with severe glaucoma to maintain active social participation-a key component to successful aging.

  14. Experimental study of the counting loss in an ionization chamber in pulsed radiation fields

    International Nuclear Information System (INIS)

    Goncalez, O.L.; Yanagihara, L.S.; Veissid, V.L.C.P.; Herdade, S.B.; Teixeira, A.N.

    1983-01-01

    The behavior of an ionization chamber gamma ray monitor in a pulsed radiation field at a linear electron accelerator facility was studied experiementally. A loss of sensitivity was observed as expected due to the pulsed nature of the radiation. By fitting the experiemental data to semi-empirical expressions, parameters for the correction of the counting efficiency were obtained. (Author) [pt

  15. 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.

  16. Altitudinal patterns of diversity and functional traits of metabolically active microorganisms in stream biofilms

    Science.gov (United States)

    Wilhelm, Linda; Besemer, Katharina; Fragner, Lena; Peter, Hannes; Weckwerth, Wolfram; Battin, Tom J

    2015-01-01

    Resources structure ecological communities and potentially link biodiversity to energy flow. It is commonly believed that functional traits (generalists versus specialists) involved in the exploitation of resources depend on resource availability and environmental fluctuations. The longitudinal nature of stream ecosystems provides changing resources to stream biota with yet unknown effects on microbial functional traits and community structure. We investigated the impact of autochthonous (algal extract) and allochthonous (spruce extract) resources, as they change along alpine streams from above to below the treeline, on microbial diversity, community composition and functions of benthic biofilms. Combining bromodeoxyuridine labelling and 454 pyrosequencing, we showed that diversity was lower upstream than downstream of the treeline and that community composition changed along the altitudinal gradient. We also found that, especially for allochthonous resources, specialisation by biofilm bacteria increased along that same gradient. Our results suggest that in streams below the treeline biofilm diversity, specialisation and functioning are associated with increasing niche differentiation as potentially modulated by divers allochthonous and autochthonous constituents contributing to resources. These findings expand our current understanding on biofilm structure and function in alpine streams. PMID:25978543

  17. Combined effects of space charge and energetic disorder on photocurrent efficiency loss of field-dependent organic photovoltaic devices

    International Nuclear Information System (INIS)

    Yoon, Sangcheol; Hwang, Inchan; Park, Byoungchoo

    2015-01-01

    The loss of photocurrent efficiency by space-charge effects in organic solar cells with energetic disorder was investigated to account for how energetic disorder incorporates space-charge effects, utilizing a drift-diffusion model with field-dependent charge-pair dissociation and suppressed bimolecular recombination. Energetic disorder, which induces the Poole–Frenkel behavior of charge carrier mobility, is known to decrease the mobility of charge carriers and thus reduces photovoltaic performance. We found that even if the mobilities are the same in the absence of space-charge effects, the degree of energetic disorder can be an additional parameter affecting photocurrent efficiency when space-charge effects occur. Introducing the field-dependence parameter that reflects the energetic disorder, the behavior of efficiency loss with energetic disorder can differ depending on which charge carrier is subject to energetic disorder. While the energetic disorder that is applied to higher-mobility charge carriers decreases photocurrent efficiency further, the efficiency loss can be suppressed when energetic disorder is applied to lower-mobility charge carriers. (paper)

  18. 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.

  19. 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

  20. Radiographs and low field MRI (0.2T) as predictors of efficacy in a weight loss trial in obese women with knee osteoarthritis

    DEFF Research Database (Denmark)

    Gudbergsen, Henrik; Boesen, Mikael; Christensen, Robin

    2011-01-01

    To study the predictive value of baseline radiographs and low-field (0.2T) MRI scans for the symptomatic outcome of clinically significant weight loss in obese patients with knee osteoarthritis.......To study the predictive value of baseline radiographs and low-field (0.2T) MRI scans for the symptomatic outcome of clinically significant weight loss in obese patients with knee osteoarthritis....

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

    Directory of Open Access Journals (Sweden)

    Katrin Sippel

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

  2. Equating spatial summation in visual field testing reveals greater loss in optic nerve disease.

    Science.gov (United States)

    Kalloniatis, Michael; Khuu, Sieu K

    2016-07-01

    To test the hypothesis that visual field assessment in ocular disease measured with target stimuli within or close to complete spatial summation results in larger threshold elevation compared to when measured with the standard Goldmann III target size. The hypothesis predicts a greater loss will be identified in ocular disease. Additionally, we sought to develop a theoretical framework that would allow comparisons of thresholds with disease progression when using different Goldmann targets. The Humphrey Field Analyser (HFA) 30-2 grid was used in 13 patients with early/established optic nerve disease using the current Goldmann III target size or a combination of the three smallest stimuli (target size I, II and III). We used data from control subjects at each of the visual field locations for the different target sizes to establish the number of failed points (events) for the patients with optic nerve disease, as well as global indices for mean deviation (MD) and pattern standard deviation (PSD). The 30-2 visual field testing using alternate target size stimuli showed that all 13 patients displayed more defects (events) compared to the standard Goldmann III target size. The median increase for events was seven additional failed points: (range 1-26). The global indices also increased when the new testing approach was used (MD -3.47 to -6.25 dB and PSD 4.32 to 6.63 dB). Spatial summation mapping showed an increase in critical area (Ac) in disease and overall increase in thresholds when smaller target stimuli were used. When compared to the current Goldmann III paradigm, the use of alternate sized targets within the 30-2 testing protocol revealed a greater loss in patients with optic nerve disease for both event analysis and global indices (MD and PSD). We therefore provide evidence in a clinical setting that target size is important in visual field testing. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  3. Measurements of Plasma Power Losses in the C-2 Field-Reversed Configuration Experiment

    Science.gov (United States)

    Korepanov, Sergey; Smirnov, Artem; Garate, Eusebio; Donin, Alexandr; Kondakov, Alexey; Singatulin, Shavkat

    2013-10-01

    A high-confinement operating regime with plasma lifetimes significantly exceeding past empirical scaling laws was recently obtained by combining plasma gun edge biasing and tangential Neutral Beam Injection in the C-2 field-reversed configuration (FRC) experiment. To analyze the power balance in C-2, two new diagnostic instruments - the pyroelectric (PE) and infrared (IR) bolometers - were developed. The PE bolometer, designed to operate in the incident power density range from 0.1-100 W/cm2, is used to measure the radial power loss, which is dominated by charge-exchange neutrals and radiation. The IR bolometer, which measures power irradiated onto a thin metal foil inserted in the plasma, is designed for the power density range from 0.5-5 kW/cm2. The IR bolometer is used to measure the axial power loss from the plasma near the end divertors. The maximum measurable pulse duration of ~ 10 ms is limited by the heat capacitance of the IR detector. Both detectors have time resolution of about 10-100 μs and were calibrated in absolute units using a high power neutral beam. We present the results of first direct measurements of axial and radial plasma power losses in C-2.

  4. A new loss mechanism in graphene nanoresonators due to the synthetic electric fields caused by inherent out-of-plane membrane corrugations

    International Nuclear Information System (INIS)

    Firsova, N E; Firsov, Yu A

    2012-01-01

    For the first time the influence of out-of-plane deformations, which always exist in graphene, on the non-stationary processes is considered for the case of a monolayer graphene nanoresonator. A new loss mechanism for this device caused by dissipative intra-valley currents stipulated by synthetic electric fields is studied. These fields are generated by time-dependent gauge fields arising in a graphene membrane due to its intrinsic out-of-plane distortions and the influence of the external periodic electromotive force. The corresponding formula for the quality factor has a quantum mechanical origin and includes quantum mechanical parameters. This loss mechanism accounts for an essential part (about 40%) of losses in a graphene nanoresonator and it is specific just for graphene. The ways of minimization of this kind of dissipation (an increase in the quality factor of the electromechanical system) are discussed. It is explained why one can enhance the quality factor by correctly choosing a combination of strains (by strain engineering). In addition, it is shown that the quality factor can be increased by switching on a magnetic field perpendicular to the graphene membrane.

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

    International Nuclear Information System (INIS)

    Motojima, Osamu; Shishkin, A.A.; Inagaki, Shigeru; Watanabe, Kiyomasa

    1999-08-01

    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)

  6. Ignored fungal community in activated sludge wastewater treatment plants: diversity and altitudinal characteristics.

    Science.gov (United States)

    Niu, Lihua; Li, Yi; Xu, Lingling; Wang, Peifang; Zhang, Wenlong; Wang, Chao; Cai, Wei; Wang, Linqiong

    2017-02-01

    Fungi are important contributors to the various functions of activated sludge wastewater treatment plants (WWTPs); however, the diversity and geographic characteristics of fungal populations have remained vastly unexplored. Here, quantitative polymerase chain reaction and 454 pyrosequencing were combined to investigate the abundance and diversity of the activated sludge fungal communities from 18 full-scale municipal WWTPs in China. Phylogenetic taxonomy revealed that the members of the fungal communities were assigned to 7 phyla and 195 genera. Ascomycota and Basidiomycota were the most abundant phyla, dominated by Pluteus, Wickerhamiella, and Penicillium. Twenty-three fungal genera, accounting for 50.1 % of the total reads, were shared by 18 WWTPs and constituted a core fungal community. The fungal communities presented similar community diversity but different community structures across the WWTPs. Significant distance decay relationships were observed for the dissimilarity in fungal community structure and altitudinal distance between WWTPs. Additionally, the community evenness increased from 0.25 to 0.7 as the altitude increased. Dissolved oxygen and the C/N ratio were determined to be the most dominant contributors to the variation in fungal community structure via redundancy analysis. The observed data demonstrated the diverse occurrence of fungal species and gave a marked view of fungal community characteristics based on the previously unexplored fungal communities in activated sludge WWTPs.

  7. Corridor- and stopover-use of the Hawaiian goose (Branta sandvicensis), an intratropical altitudinal migrant

    Science.gov (United States)

    Leopold, Christina R.; Hess, Steven C.

    2014-01-01

    We outfitted six male Hawaiian geese, or nene (Branta sandvicensis), with 45-g solar-powered satellite transmitters and collected four location coordinates d−1 from 2010 to 2012. We used 6193 coordinates to characterize migration corridors, habitat preferences and temporal patterns of displacement for 16 migration events with Brownian bridge utilization distributions (BBUD). We used 1552 coordinates to characterize stopovers from 37 shorter-distance movement events with 25% BBUDs. Two subpopulations used a well-defined common migration corridor spanning a broad gradient of elevation. Use of native-dominated subalpine shrubland was 2.81 times more likely than the availability of this land-cover type. The nene differed from other tropical and temperate-zone migrant birds in that: (1) migration distance and the number of stopovers were unrelated (Mann–Whitney test W = 241, P movements were not unidirectional suggesting that social interactions may be more important than refuelling en route; but like other species, nene made more direct migrations with fewer stopovers in return to breeding areas (0.58 ± 0.50) than in migration away from breeding areas (1.64 ± 0.48). Our findings, combined with the direction and timing of migration, which is opposite that of most other intratropical migrants, suggest fundamentally different drivers of altitudinal migration.

  8. Application of polyacrylamide to reduce phosphorus losses from a Chinese purple soil: a laboratory and field investigation.

    Science.gov (United States)

    Jiang, Tao; Teng, Lingling; Wei, Shiqiang; Deng, Lili; Luo, Zaibo; Chen, Yupeng; Flanagan, Dennis C

    2010-07-01

    Use of anionic polyacrylamide (PAM) to control phosphorus (P) losses from a Chinese purple soil was studied in both a laboratory soil column experiment and a field plot experiment on a steep slope (27%). Treatments in the column study were a control, and PAM mixed uniformly into the soil at rates of 0.02, 0.05, 0.08, 0.10, and 0.20%. We found that PAM had an important inhibitory effect on vertical P transport in the soil columns, with the 0.20% PAM treatment having the greatest significant reduction in leachate soluble P concentrations and losses resulting from nine leaching periods. Field experiments were conducted on 5m wide by 21m long natural rainfall plots, that allowed collection of both surface runoff and subsurface drainage water. Wheat was planted and grown on all plots with typical fertilizer applied. Treatments included a control, dry PAM at 3.9 kg ha(-1), dry PAM at 3.9 kg ha(-1) applied together with lime (CaCO(3) at 4.9 t ha(-1)), and dry PAM at 3.9 kg ha(-1) applied together with gypsum (CaSO(4).2H(2)O at 4 t ha(-1)). Results from the field plot experiment in which 5 rainfall events resulted in measurable runoff and leachate showed that all PAM treatments significantly reduced runoff volume and total P losses in surface runoff compared to the control. The PAM treatments also all significantly reduced water volume leached to the tile drain. However, total P losses in the leachate water were not significantly different due to the treatments, perhaps due to the low PAM soil surface application rate and/or high experimental variability. The PAM alone treatment resulted in the greatest wheat growth as indicated by the plant growth indexes of wheat plant height, leaf length, leaf width, grain number per head, and dried grain mass. Growth indexes of the PAM with Calcium treatments were significantly lesser. These results indicate that the selection and use of soil amendments need to be carefully determined based upon the most important management goal at a

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

    Directory of Open Access Journals (Sweden)

    Elangovan Suma, Puri K Sanjeev

    2013-10-01

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

  10. Visual Field Defects and Retinal Ganglion Cell Losses in Human Glaucoma Patients

    Science.gov (United States)

    Harwerth, Ronald S.; Quigley, Harry A.

    2007-01-01

    Objective The depth of visual field defects are correlated with retinal ganglion cell densities in experimental glaucoma. This study was to determine whether a similar structure-function relationship holds for human glaucoma. Methods The study was based on retinal ganglion cell densities and visual thresholds of patients with documented glaucoma (Kerrigan-Baumrind, et al.) The data were analyzed by a model that predicted ganglion cell densities from standard clinical perimetry, which were then compared to histologic cell counts. Results The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell densities associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs. measured cell densities had a coefficient of determination of 0.39. The mean absolute deviation of the predicted vs. measured values was 2.59 dB, the mean and SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions Visual field defects by standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance The evidence for quantitative structure-function relationships provides a scientific basis of interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease. PMID:16769839

  11. 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.

  12. Bipolar energy-loss measurements on cryostable, low-loss conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wollan, J.J.

    1981-01-01

    Losses have been measured on a prototype conductor for the 20 MJ coil for conditions which simulate closely the actual coil field sweep. The data on the prototype II conductor indicates coil losses which exceed the coil specification. The application of certain correction factors reduces the projected losses within the specification for a 2 s reversal but not for a 1 s reversal. Verification of these corrections await measurements on the actual strand and completion of coil construction and testing.

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Field grain losses and insect pest management practices in ...

    African Journals Online (AJOL)

    Journal of Agriculture, Science and Technology ... Statistical analyses revealed that the level of crop yield losses was ... There was, however, a negative correlation between crop yield loss due to insect pests and the efficacy of PCM applied.

  15. The loss rates of O+ in the inner magnetosphere caused by both magnetic field line curvature scattering and charge exchange reactions

    Science.gov (United States)

    Ji, Y.; Shen, C.

    2014-03-01

    With consideration of magnetic field line curvature (FLC) pitch angle scattering and charge exchange reactions, the O+ (>300 keV) in the inner magnetosphere loss rates are investigated by using an eigenfunction analysis. The FLC scattering provides a mechanism for the ring current O+ to enter the loss cone and influence the loss rates caused by charge exchange reactions. Assuming that the pitch angle change is small for each scattering event, the diffusion equation including a charge exchange term is constructed and solved; the eigenvalues of the equation are identified. The resultant loss rates of O+ are approximately equal to the linear superposition of the loss rate without considering the charge exchange reactions and the loss rate associated with charge exchange reactions alone. The loss time is consistent with the observations from the early recovery phases of magnetic storms.

  16. Structure-based capacitance modeling and power loss analysis for the latest high-performance slant field-plate trench MOSFET

    Science.gov (United States)

    Kobayashi, Kenya; Sudo, Masaki; Omura, Ichiro

    2018-04-01

    Field-plate trench MOSFETs (FP-MOSFETs), with the features of ultralow on-resistance and very low gate–drain charge, are currently the mainstream of high-performance applications and their advancement is continuing as low-voltage silicon power devices. However, owing to their structure, their output capacitance (C oss), which leads to main power loss, remains to be a problem, especially in megahertz switching. In this study, we propose a structure-based capacitance model of FP-MOSFETs for calculating power loss easily under various conditions. Appropriate equations were modeled for C oss curves as three divided components. Output charge (Q oss) and stored energy (E oss) that were calculated using the model corresponded well to technology computer-aided design (TCAD) simulation, and we validated the accuracy of the model quantitatively. In the power loss analysis of FP-MOSFETs, turn-off loss was sufficiently suppressed, however, mainly Q oss loss increased depending on switching frequency. This analysis reveals that Q oss may become a significant issue in next-generation high-efficiency FP-MOSFETs.

  17. An improved oxygen diffusion model to explain the effect of low-temperature baking on high field losses in niobium superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi

    2006-07-01

    Radio-frequency (RF) superconducting cavities made of high purity niobium are widely used to accelerate charged particle beams in particle accelerators. The major limitation to achieve RF field values approaching the theoretical limit for niobium is represented by ''anomalous'' losses which degrade the quality factor of the cavities starting at peak surface magnetic fields of about 100 mT, in absence of field emission. These high field losses are often referred to as ''Q-drop''. It has been observed that the Q-drop is drastically reduced by baking the cavities at 120 C for about 48 h under ultrahigh vacuum. An improved oxygen diffusion model for the niobium-oxide system is proposed to explain the benefit of the low-temperature baking on the Q-drop in niobium superconducting rf cavities. The model shows that baking at 120 C for 48 h allows oxygen to diffuse away from the surface, and therefore increasing the lower critical field towards the value for pure niobium.

  18. Whole-field macro- and micro-deformation characteristic of unbound water-loss in dentin hard tissue.

    Science.gov (United States)

    Chen, Zhenning; Nadeau, Bobby; Yu, Kevin; Shao, Xinxing; He, Xiaoyuan; Goh, M Cynthia; Kishen, Anil

    2018-04-06

    High-resolution deformation measurements in a functionally graded hard tissue such as human dentin are essential to understand the unbound water-loss mediated changes and their role in its mechanical integrity. Yet a whole-field, 3-dimensional (3D) measurement and characterization of fully hydrated dentin in both macro- and micro-scales remain to be a challenge. This study was conducted in 2 stages. In stage-1, a stereo-digital image correlation approach was utilized to determine the water-loss and load-induced 3D deformations of teeth in a sagittal section over consecutively acquired frames, from a fully hydrated state to nonhydrated conditions for a period up to 2 hours. The macroscale analysis revealed concentrated residual deformations at the dentin-enamel-junction and the apical regions of root in the direction perpendicular to the dentinal tubules. Significant difference in the localized deformation characteristics was observed between the inner and outer aspects of the root dentin. During quasi-static loadings, further increase in the residual deformation was observed in the dentin. In stage-2, dentin microstructural variations induced by dynamic water-loss were assessed with environmental scanning electron microscopy and atomic force microscopy (AFM), showing that the dynamic water-loss induced distention of dentinal tubules with concave tubular edges, and concurrent contraction of intertubular dentin with convex profile. The findings from the current macro- and micro-scale analysis provided insight on the free-water-loss induced regional deformations and ultrastructural changes in human dentin. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Seasonal and Altitudinal Prevalence of Fascioliasis in Buffalo in Eastern Nepal

    Directory of Open Access Journals (Sweden)

    Ramesh Prasad Sah

    2018-05-01

    Full Text Available Buffalo is the most important livestock commodities for milk, meat production and several other multipurpose uses distributed densely from southern tarai to northern mid-hills in Nepal. Among several internal parasitic diseases fascioliasis is highly economic one caused by Fasciola in buffaloes. However, there are only few studies carried on prevalence of fascioliasis emphasizing buffaloes in relation to seasonal (summer and rainy, and winter and altitudinal variations. Therefore, we examined prevalence of fascioliasis seasonally and vertically. For the purpose, we selected two districts of eastern Nepal and sampled from low altitude area known as Madhesha ranging from 175-200, Dhankuta from 800-1200 m, and Murtidhunga from 1800-2200 m elevation from the sea level, representing tarai, mid hills and high hills, respectively. Altogether from February 2013 to January 2014 at every two months interval we collected 798 fecal samples from buffaloes; 282 from Murtidhunga, 239 from Dhankuta and 277 from Madhesha. The samples were examined microscopically for the presence of Fasciola eggs using sedimentation technique. Results showed that overall prevalence of fascioliasis in buffaloes was 39.9% (319/798, ranging highest 42.6%in Madhesha followed by 39.7% in Murtidhunga and 37.2% in Dhankuta, respectively. The prevalence of fascioliasis was found to be significantly (p <0.05 high in winter (44.9% comparing to rainy season (34.4%. The prevalence of fascioliasis in buffaloes was relatively higher in low altitude than high altitude, although it was not statistically significant (p <0.05. In our findings the female buffaloes showed higher prevalence for fascioliasis than in male. Since the fascioliasis in buffaloes is highly endemic, thus strategic deworming in high risk period is recommended along with measure to prevent pasture contamination with buffalo feces.

  20. Exploring the effects of nitrogen fertilization management alternatives on nitrate loss and crop yields in tile-drained fields in Illinois.

    Science.gov (United States)

    Jeong, Hanseok; Bhattarai, Rabin

    2018-05-01

    It is vital to manage the excessive use of nitrogen (N) fertilizer in corn production, the single largest consumer of N fertilizer in the United States, in order to achieve more sustainable agroecosystems. This study comprehensively explored the effects of N fertilization alternatives on nitrate loss and crop yields using the Root Zone Water Quality Model (RZWQM) in tile-drained fields in central Illinois. The RZWQM was tested for the prediction of tile flow, nitrate loss, and crop yields using eight years (1993-2000) of observed data and showed satisfactory model performances from statistical and graphical evaluations. Our model simulations demonstrated the maximum return to nitrogen (MRTN) rate (193 kgha -1 ), a newly advised N recommendation by the Illinois Nutrient Loss Reduction Strategy (INLRS), can be further reduced. Nitrate loss was reduced by 10.3% and 29.8%, but corn yields decreased by 0.3% and 1.9% at 156 and 150 kgha -1 of N fertilizer rate in the study sites A and E, respectively. Although adjustment of N fertilization timing presented a further reduction in nitrate loss, there was no optimal timing to ensure nitrate loss reduction and corn productivity. For site A, 100% spring application was the most productive and 40% fall, 10% pre-plant, and 50% side dress application generated the lowest nitrate loss. For site E, the conventional N application timing was verified as the best practice in both corn production and nitrate loss reduction. Compared to surface broadcast placement, injected N fertilizer in spring increased corn yield, but may also escalate nitrate loss. This study presented the need of an adaptive N fertilizer management due to the heterogeneity in agricultural systems, and raised the importance of timing and placement of N fertilizer, as well as further reduction in fertilizer rate to devise a better in-field N management practice. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Fast Winds and Mass Loss from Metal-Poor Field Giants

    Science.gov (United States)

    Dupree, A. K.; Smith, Graeme H.; Strader, Jay

    2009-11-01

    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 effgsim 4500 K and MV fainter than -1.5, and reveals the dynamics of the atmosphere. The line strength increases with effective temperature for T effgsim 5300 K in RHB stars. In AGB and RGB stars, the line strength increases with luminosity. Fast outflows (gsim 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 × 10-10 to ~6 × 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. Data presented herein were obtained at the W. M. Keck Observatory, which

  2. The Mars Crustal Magnetic Field Control of Plasma Boundary Locations and Atmospheric Loss: MHD Prediction and Comparison with MAVEN

    Science.gov (United States)

    Fang, Xiaohua; Ma, Yingjuan; Masunaga, Kei; Dong, Chuanfei; Brain, David; Halekas, Jasper; Lillis, Robert; Jakosky, Bruce M.; Connerney, Jack; Grebowsky, Joseph; hide

    2017-01-01

    We present results from a global Mars time-dependent MHD simulation under constant solar wind and solar radiation impact considering inherent magnetic field variations due to continuous planetary rotation. We calculate the 3-D shapes and locations of the bow shock (BS) and the induced magnetospheric boundary (IMB) and then examine their dynamic changes with time. We develop a physics-based, empirical algorithm to effectively summarize the multidimensional crustal field distribution. It is found that by organizing the model results using this new approach, the Mars crustal field shows a clear, significant influence on both the IMB and the BS. Specifically, quantitative relationships have been established between the field distribution and the mean boundary distances and the cross-section areas in the terminator plane for both of the boundaries. The model-predicted relationships are further verified by the observations from the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Our analysis shows that the boundaries are collectively affected by the global crustal field distribution, which, however, cannot be simply parameterized by a local parameter like the widely used subsolar longitude. Our calculations show that the variability of the intrinsic crustal field distribution in Mars-centered Solar Orbital itself may account for approx.60% of the variation in total atmospheric loss, when external drivers are static. It is found that the crustal field has not only a shielding effect for atmospheric loss but also an escape-fostering effect by positively affecting the transterminator ion flow cross-section area.

  3. 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.

  4. 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

  5. A.C. losses in current-carrying superconductors

    International Nuclear Information System (INIS)

    Reuver, J.L. de.

    1985-01-01

    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.)

  6. The loss rates of O{sup +} in the inner magnetosphere caused by both magnetic field line curvature scattering and charge exchange reactions

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Y., E-mail: yji@spaceweather.ac.cn [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, C. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-03-15

    With consideration of magnetic field line curvature (FLC) pitch angle scattering and charge exchange reactions, the O{sup +} (>300 keV) in the inner magnetosphere loss rates are investigated by using an eigenfunction analysis. The FLC scattering provides a mechanism for the ring current O{sup +} to enter the loss cone and influence the loss rates caused by charge exchange reactions. Assuming that the pitch angle change is small for each scattering event, the diffusion equation including a charge exchange term is constructed and solved; the eigenvalues of the equation are identified. The resultant loss rates of O{sup +} are approximately equal to the linear superposition of the loss rate without considering the charge exchange reactions and the loss rate associated with charge exchange reactions alone. The loss time is consistent with the observations from the early recovery phases of magnetic storms.

  7. 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

  8. Simulating water and nitrogen loss from an irrigated paddy field under continuously flooded condition with Hydrus-1D model.

    Science.gov (United States)

    Yang, Rui; Tong, Juxiu; Hu, Bill X; Li, Jiayun; Wei, Wenshuo

    2017-06-01

    Agricultural non-point source pollution is a major factor in surface water and groundwater pollution, especially for nitrogen (N) pollution. In this paper, an experiment was conducted in a direct-seeded paddy field under traditional continuously flooded irrigation (CFI). The water movement and N transport and transformation were simulated via the Hydrus-1D model, and the model was calibrated using field measurements. The model had a total water balance error of 0.236 cm and a relative error (error/input total water) of 0.23%. For the solute transport model, the N balance error and relative error (error/input total N) were 0.36 kg ha -1 and 0.40%, respectively. The study results indicate that the plow pan plays a crucial role in vertical water movement in paddy fields. Water flow was mainly lost through surface runoff and underground drainage, with proportions to total input water of 32.33 and 42.58%, respectively. The water productivity in the study was 0.36 kg m -3 . The simulated N concentration results revealed that ammonia was the main form in rice uptake (95% of total N uptake), and its concentration was much larger than for nitrate under CFI. Denitrification and volatilization were the main losses, with proportions to total consumption of 23.18 and 14.49%, respectively. Leaching (10.28%) and surface runoff loss (2.05%) were the main losses of N pushed out of the system by water. Hydrus-1D simulation was an effective method to predict water flow and N concentrations in the three different forms. The study provides results that could be used to guide water and fertilization management and field results for numerical studies of water flow and N transport and transformation in the future.

  9. Distribution and diversity of Tardigrada along altitudinal gradients in the Hornsund, Spitsbergen (Arctic

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawierucha

    2015-02-01

    Full Text Available Two transects were established and sampled along altitudinal gradients on the slopes of Ariekammen (77°01′N; 15°31′E and Rotjesfjellet (77°00′N; 15°22′E in Hornsund, Spitsbergen. In total 59 moss, lichen, liverwort and mixed moss–lichen samples were collected and 33 tardigrade species of Hetero- and Eutardigrada were found. The α diversity ranged from 1 to 8 per sample; the estimated number of species based on all analysed samples was 52±17 for the Chao 2 estimator and 41 for the incidence-based coverage estimator. According to the results of detrended canonical correspondence analysis, altitude and type of substratum were the most important factors influencing tardigrade communities in the investigated area. Macrobiotus crenulatus, M. hufelandi hufelandi and Hypsibius pallidus dominated in the lower elevations, whereas Echiniscus wendti and E. merokensis merokensis prevailed in samples from higher plots. Macrobiotus islandicus islandicus was collected most often from mosses collected from rock whereas Isohypsibius coulsoni from mosses collected from soil. Analyses of covariance were employed to test for differences in species richness between the transects in relation to altitude. Contrary to expectations, there were significant differences in species richness between the transects, but richness was not significantly related to altitude. Interestingly, significant effects of colonies of seabirds, little auk (Alle alle, on the tardigrades communities were detected. Additionally, in one of the samples first ever males of Milnesium asiaticum were found. Their measurements and microphotographs are provided herein.

  10. The effect of quadrupole fields on particle confinement in a field-reversed mirror

    International Nuclear Information System (INIS)

    McColl, D.B.; Berk, H.L.; Hammer, J.; Morse, E.C.

    1982-01-01

    A particle simulation code has been modified to simulate particle loss caused by quadrupole magnetic fields on a field-reversed mirror plasma device. Since analytic fields are chosen for the equilibrium, the numerical algorithm is highly accurate for long-time integrations of particle orbits. The resultant particle loss due to the quadrupole fields can be competitive with collisional loss in the device

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

    International Nuclear Information System (INIS)

    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 16 cm -3 and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10 16 cm -3 and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil

  12. The effect of air flow, panel curvature, and internal pressurization on field-incidence transmission loss. [acoustic propagation through aircraft fuselage

    Science.gov (United States)

    Koval, L. R.

    1975-01-01

    In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. These effects are incorporated into the classical equations for the TL of single panels, and the resulting double integral for field-incidence TL is numerically evaluated for a specific set of parameters.

  13. 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...

  14. Study of the Effect of Transport Current and Combined Transverse and Longitudinal Fields on the AC Loss in NET Prototype Conductors

    NARCIS (Netherlands)

    Nijhuis, Arend; ten Kate, Herman H.J.

    1994-01-01

    AC losses in cables carrying DC as well as AC transport currents at different DC background fields up to 2T have been measured on three types of Nb3Sn subcables in a new test facility. In this facility it is possible to apply sinusoidal transverse AC fields up to dB/dt=5T/s and longitudinal AC

  15. 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.

  16. Effect of loss cone on confinement in toroidal helical device

    International Nuclear Information System (INIS)

    Itoh, K.; Itoh, S.-I.; Fukuyama, A.; Hanatani, K.

    1988-12-01

    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)

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

    Directory of Open Access Journals (Sweden)

    M.R Mostofi Sarkari

    2014-09-01

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

  18. The Generalized Multipole Technique for the Simulation of Low-Loss Electron Energy Loss Spectroscopy

    DEFF Research Database (Denmark)

    Kiewidt, Lars; Karamehmedovic, Mirza

    2018-01-01

    In this study, we demonstrate the use of a Generalized Multipole Technique (GMT) to simulate low-loss Electron Energy Loss Spectroscopy (EELS) spectra of isolated spheriodal nanoparticles. The GMT provides certain properties, such as semi-analytical description of the electromagnetic fields...

  19. Vector Control Using Series Iron Loss Model of Induction, Motors and Power Loss Minimization

    OpenAIRE

    Kheldoun Aissa; Khodja Djalal Eddine

    2009-01-01

    The iron loss is a source of detuning in vector controlled induction motor drives if the classical rotor vector controller is used for decoupling. In fact, the field orientation will not be satisfied and the output torque will not truck the reference torque mostly used by Loss Model Controllers (LMCs). In addition, this component of loss, among others, may be excessive if the vector controlled induction motor is driving light loads. In this paper, the series iron loss model ...

  20. AC magnetization loss characteristics of HTS coated-conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Liu, M.; Odaka, S.; Miyagi, D.; Ohmatsu, K.

    2007-01-01

    AC magnetization loss characteristics of an HTS coated tape conductor with magnetic substrate subjected to an external AC magnetic field were investigated. The external magnetic field was perpendicular or parallel to the wide face of the tape conductor. Magnetization losses in the conductor and in the magnetic substrate itself without the superconductor layer, were measured by electric and calorimetric methods. The influence of the magnetic property of the substrate was strongly dependent on the direction of the external magnetic field. When the external magnetic field was perpendicular, magnetic property of the substrate did not affect the magnetization loss characteristics. This result suggests that the magnetization losses can be reduced by subdivisions of the superconducting layers even in the case of magnetic substrate conductors. When the external magnetic field was parallel, the magnetization losses were dominated by the losses in the magnetic substrate. Therefore, to reduce the magnetization losses in this case, reduction of magnetization losses in the substrate is necessary

  1. Occurrence of CYP1B1 Mutations in Juvenile Open-Angle Glaucoma With Advanced Visual Field Loss.

    Science.gov (United States)

    Souzeau, Emmanuelle; Hayes, Melanie; Zhou, Tiger; Siggs, Owen M; Ridge, Bronwyn; Awadalla, Mona S; Smith, James E H; Ruddle, Jonathan B; Elder, James E; Mackey, David A; Hewitt, Alex W; Healey, Paul R; Goldberg, Ivan; Morgan, William H; Landers, John; Dubowsky, Andrew; Burdon, Kathryn P; Craig, Jamie E

    2015-07-01

    Juvenile open-angle glaucoma (JOAG) is a severe neurodegenerative eye disorder in which most of the genetic contribution remains unexplained. To assess the prevalence of pathogenic CYP1B1 sequence variants in an Australian cohort of patients with JOAG and severe visual field loss. For this cohort study, we recruited 160 patients with JOAG classified as advanced (n = 118) and nonadvanced (n = 42) through the Australian and New Zealand Registry of Advanced Glaucoma from January 1, 2007, through April 1, 2014. Eighty individuals with no evidence of glaucoma served as a control group. We defined JOAG as diagnosis before age 40 years and advanced JOAG as visual field loss in 2 of the 4 central fixation squares on a reliable visual field test result. We performed direct sequencing of the entire coding region of CYP1B1. Data analysis was performed in October 2014. Identification and characterization of CYP1B1 sequence variants. We identified 7 different pathogenic variants among 8 of 118 patients with advanced JOAG (6.8%) but none among the patients with nonadvanced JOAG. Three patients were homozygous or compound heterozygous for CYP1B1 pathogenic variants, which provided a likely basis for their disease. Five patients were heterozygous. The allele frequency among the patients with advanced JOAG (11 in 236 [4.7%]) was higher than among our controls (1 in 160 [0.6%]; P = .02; odds ratio, 7.8 [95% CI, 0.02-1.0]) or among the control population from the Exome Aggregation Consortium database (2946 of 122 960 [2.4%]; P = .02; odds ratio, 2.0 [95% CI, 0.3-0.9]). Individuals with CYP1B1 pathogenic variants, whether heterozygous or homozygous, had worse mean (SD) deviation on visual fields (-24.5 [5.1] [95% CI, -31.8 to -17.2] vs -15.6 [10.0] [95% CI, -17.1 to -13.6] dB; F1,126 = 5.90; P = .02; partial ηp2 = 0.05) and were younger at diagnosis (mean [SD] age, 23.1 [8.4] [95% CI, 17.2-29.1] vs 31.5 [8.0] [95% CI, 30.1-33.0] years; F1,122 = 7

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

    International Nuclear Information System (INIS)

    Dahlgaard, H.

    1999-01-01

    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)

  3. Correlation between local glaucomatous visual field defects and loss of nerve fiber layer thickness measured with polarimetry and spectral domain OCT.

    Science.gov (United States)

    Horn, Folkert K; Mardin, Christian Y; Laemmer, Robert; Baleanu, Delia; Juenemann, Anselm M; Kruse, Friedrich E; Tornow, Ralf P

    2009-05-01

    To study the correlation between local perimetric field defects and glaucoma-induced thickness reduction of the nerve layer measured in the peripapillary area with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with those of a theoretical model. The thickness of the retinal nerve fiber layer was determined in 32 sectors (11.25 degrees each) by using SLP with variable cornea compensation (GDxVCC; Laser Diagnostics, San Diego, CA) and the newly introduced high-resolution SOCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). Eighty-eight healthy subjects served as control subjects, to determine the thickness deviation in patients with glaucoma. The relationship between glaucomatous nerve fiber reduction and visual field losses was calculated in six nerve fiber bundle-related areas. Sixty-four patients at different stages of open-angle glaucoma and 26 patients with ocular hypertension underwent perimetry (Octopus G1; Haag-Streit, Köniz, Switzerland) and measurements with the two morphometric techniques. Sector-shaped analyses between local perimetric losses and reduction of the retinal nerve fiber layer thickness showed a significant association for corresponding areas except for the central visual field in SLP. Correlation coefficients were highest in the area of the nasal inferior visual field (SOCT, -0.81; SLP, -0.57). A linear model describes the association between structural and functional damage. Localized perimetric defects can be explained by reduced nerve fiber layer thickness. The data indicate that the present SOCT is useful for determining the functional-structural relationship in peripapillary areas and that association between perimetric defects and corresponding nerve fiber losses is stronger for SOCT than for the present SLP. (ClinicalTrials.gov number, NCT00494923.).

  4. Preliminary Analysis on Linac Oscillation Data LI05-19 and Wake Field Energy Loss in FACET Commissioning 2012

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yipeng; /SLAC

    2012-07-23

    In this note, preliminary analysis on linac ocsillation data in FACET linac LI05-09 plus LI11-19 is presented. Several quadrupoles are identified to possibly have different strength, compared with their designed strength in the MAD optics model. The beam energy loss due to longitudinal wake fields in the S-band linac is also analytically calculated, also by LITRACK numerical simulations.

  5. Ion heat conduction losses in Extrap

    International Nuclear Information System (INIS)

    Tennfors, E.

    1989-08-01

    The classical ion heat conduction losses in Extrap discharges are calculated using polynomial magnetic field profiles and compared to the power input. For polynomials matched to magnetic field profiles measured in present experiments, these losses are small. By varying the coefficients of the polynomials, a region is found, where the power input can balance the classical heat conduction losses. Each set of coefficients corresponds to values of the parameters F and Θ used in RFP physics. The region determines a region in an F-Θ diagram, including the usual RFP region but extending to higher values of Θ and βΘ

  6. Ripple induced trapped particle loss in tokamaks

    International Nuclear Information System (INIS)

    White, R.B.

    1996-05-01

    The threshold for stochastic transport of high energy trapped particles in a tokamak due to toroidal field ripple is calculated by explicit construction of primary resonances, and a numerical examination of the route to chaos. Critical field ripple amplitude is determined for loss. The expression is given in magnetic coordinates and makes no assumptions regarding shape or up-down symmetry. An algorithm is developed including the effects of prompt axisymmetric orbit loss, ripple trapping, convective banana flow, and stochastic ripple loss, which gives accurate ripple loss predictions for representative Tokamak Fusion Test Reactor and International Thermonuclear Experimental Reactor equilibria. The algorithm is extended to include the effects of collisions and drag, allowing rapid estimation of alpha particle loss in tokamaks

  7. Comparison of MHD pressure losses of liquid-lithium flows in coaxial and parallel ducts, passing through strong transverse magnetic fields

    International Nuclear Information System (INIS)

    Trommer, G.

    1979-08-01

    This report deals with theoretical calculations of MHD pressure losses of liquid-lithium flows in tubes of circular cross-section exposed to strong magnetic fields. Some simplifying assumptions were introduced, yielding an analytical solution which allows the pressure drop and losses in double tubes of coaxial geometry to be compared with those in normal flow pipes. The investigations show that coaxial ducts require much more pumping power than normal ones under similar conditions. This great difference of the properties of the two duct types will decrease if the pipes are embedded in materials of good electrical conductivity. In this case the normal duct will afford a drastic increase in the pressure drop, while the coaxial one will be nearly unaffected. But even under these conditions the losses of the latter will dominate. (orig.)

  8. Timing and duration of European larch growing season along altitudinal gradients in the Swiss Alps.

    Science.gov (United States)

    Moser, Lea; Fonti, Patrick; Büntgen, Ulf; Esper, Jan; Luterbacher, Jürg; Franzen, Julia; Frank, David

    2010-02-01

    The 2007 European larch (Larix decidua Mill.) growing season was monitored along two elevational transects in the Lötschental valley in the Swiss Alps. Phenological observations and weekly microcore sampling of 28 larch trees were conducted between April and October 2007 at seven study sites regularly spaced from 1350 to 2150 m a.s.l. on northwest- and southeast-facing slopes. The developmental stages of nearly 75,000 individual cells assessed on 1200 thin sections were used to investigate the links between the trees' thermal regimes and growth phases including the beginning and ending of cell enlargement, wall thickening and maturation of the stem wood. Needles appeared approximately 3-4 weeks earlier than stem growth. The duration of ring formation lasted from mid-May to the end of October, with the length of the growing season decreasing along elevation from 137 to 101 days. The onset of the different growing seasons changed by 3-4 days per 100 m elevation; the ending of the growing season, however, appeared minimally related to altitude. If associated with the monitored altitudinal lapse rate of -0.5 degrees C per 100 m, these results translate into a lengthening of the growing season by approximately 7 days per degree Celsius. This study provides new data on the timing and duration of basic growth processes and contributes to quantification of the impacts of global warming on tree growth and productivity.

  9. 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

  10. Intrinsic rotation produced by ion orbit loss and X-loss

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Boedo, J. A. [University of California - San Diego, San Diego, California 92093 (United States); Evans, T. E.; Groebner, R. J. [General Atomics, San Diego, California 92186 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08453 (United States)

    2012-11-15

    A practical calculation model for the intrinsic rotation imparted to the edge plasma by the directionally preferential loss of ions on orbits that cross the last closed flux surface is presented and applied to calculate intrinsic rotation in several DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharges. The intrinsic rotation produced by ion loss is found to be sensitive to the edge temperature and radial electric field profiles, which has implications for driving intrinsic rotation in future large tokamaks.

  11. The Association of Glaucomatous Visual Field Loss and Balance

    Science.gov (United States)

    de Luna, Regina A.; Mihailovic, Aleksandra; Nguyen, Angeline M.; Friedman, David S.; Gitlin, Laura N.; Ramulu, Pradeep Y.

    2017-01-01

    Purpose To relate balance measures to visual field (VF) damage from glaucoma. Methods The OPAL kinematic system measured balance, as root mean square (RMS) sway, on 236 patients with suspect/diagnosed glaucoma. Balance was measured with feet shoulder width apart while standing on a firm/foam surface with eyes opened/closed (Instrumental Clinical Test of Sensory Integration and Balance [ICTSIB] conditions), and eyes open on a firm surface under feet together, semi-tandem, or tandem positions (standing balance conditions). Integrated VF (IVF) sensitivities were calculated by merging right and left eye 24-2 VF data. Results Mean age was 71 years (range, 57–93) and mean IVF sensitivity was 27.1 dB (normal = 31 dB). Lower IVF sensitivity was associated with greater RMS sway during eyes-open foam-surface testing (β = 0.23 z-score units/5 dB IVF sensitivity decrement, P = 0.001), but not during other ICTSIB conditions. Lower IVF sensitivity also was associated with greater RMS sway during feet together standing balance testing (0.10 z-score units/5 dB IVF sensitivity decrement, P = 0.049), but not during other standing balance conditions. Visual dependence of balance was lower in patients with worse IVF sensitivity (β = −21%/5 dB IVF sensitivity decrement, P falls and patients with VF loss from glaucoma may be at higher risk of falls because of poor balance. PMID:28553562

  12. 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

  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. Development and Testing of UCLA's Electron Losses and Fields Investigation (ELFIN) Instrument Payload

    Science.gov (United States)

    Wilkins, C.; Bingley, L.; Angelopoulos, V.; Caron, R.; Cruce, P. R.; Chung, M.; Rowe, K.; Runov, A.; Liu, J.; Tsai, E.

    2017-12-01

    UCLA's Electron Losses and Fields Investigation (ELFIN) is a 3U+ CubeSat mission designed to study relativistic particle precipitation in Earth's polar regions from Low Earth Orbit. Upon its 2018 launch, ELFIN will aim to address an important open question in Space Physics: Are Electromagnetic Ion-Cyclotron (EMIC) waves the dominant source of pitch-angle scattering of high-energy radiation belt charged particles into Earth's atmosphere during storms and substorms? Previous studies have indicated these scattering events occur frequently during storms and substorms, and ELFIN will be the first mission to study this process in-situ.Paramount to ELFIN's success is its instrument suite consisting of an Energetic Particle Detector (EPD) and a Fluxgate Magnetometer (FGM). The EPD is comprised of two collimated solid-state detector stacks which will measure the incident flux of energetic electrons from 50 keV to 4 MeV and ions from 50 keV to 300 keV. The FGM is a 3-axis magnetic field sensor which will capture the local magnetic field and its variations at frequencies up to 5 Hz. The ELFIN spacecraft spins perpendicular to the geomagnetic field to provide 16 pitch-angle particle data sectors per revolution. Together these factors provide the capability to address the nature of radiation belt particle precipitation by pitch-angle scattering during storms and substorms.ELFIN's instrument development has progressed into the late Engineering Model (EM) phase and will soon enter Flight Model (FM) development. The instrument suite is currently being tested and calibrated at UCLA using a variety of methods including the use of radioactive sources and applied magnetics to simulate orbit conditions during spin sectoring. We present the methods and test results from instrument calibration and performance validation.

  15. Energy losses in mixed matrix superconducting wires under fast pulsed conditions

    International Nuclear Information System (INIS)

    Wollan, J.J.

    1976-01-01

    Energy losses have been measured on a set of mixed matrix (CuNi, Cu, NbTi) superconducting wires at B's up to 1.5 x 10 7 G/s. The losses have been measured as a function of wire diameter, twist pitch, maximum applied field, and B. Both static and dynamic losses were measured for a field applied perpendicularly to the wire axis. The dynamic losses were measured by slowly applying an external field to a sample and then causing the field to decay exponentially in roughly 1 ms to 10 ms. Under low B (9 kG) and B (10 6 G/s) conditions the hysteretic loss dominated. At high B (21 kG) and B (1.5 x 10 7 G/s) the matrix losses became dominant. The systematic variation of the losses with the mentioned parameters will be presented and will be compared to theoretical predictions

  16. 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.

  17. Surface runoff and subsurface tile drain losses of neonicotinoids and companion herbicides at edge-of-field.

    Science.gov (United States)

    Chrétien, François; Giroux, Isabelle; Thériault, Georges; Gagnon, Patrick; Corriveau, Julie

    2017-05-01

    With their application as seed coatings, the use of neonicotinoid insecticides increased dramatically during the last decade. They are now frequently detected in aquatic ecosystems at concentrations susceptible to harm aquatic invertebrates at individual and population levels. This study intent was to document surface runoff and subsurface tile drain losses of two common neonicotinoids (thiamethoxam and clothianidin) compared to those of companion herbicides (atrazine, glyphosate, S-metolachlor and mesotrione) at the edge of a 22.5-ha field under a corn-soybean rotation. A total of 14 surface runoff and tile drain discharge events were sampled over two years. Events and annual unit mass losses were computed using flow-weighted concentrations and total surface runoff and tile drain flow volumes. Detection frequencies close to 100% in edge-of-field surface runoff and tile drain water samples were observed for thiamethoxam and clothianidin even though only thiamethoxam had been applied in the first year. In 2014, thiamethoxam median concentrations in surface runoff and tile drain samples were respectively 0.46 and 0.16 μg/L, while respective maximum concentrations of 2.20 and 0.44 μg/L were measured in surface runoff and tile drain samples during the first post-seeding storm event. For clothianidin, median concentrations in surface runoff and tile drain samples were 0.02 and 0.01, μg/L, and respective maximum concentrations were 0.07 μg/L and 0.05 μg/L. Surface runoff and tile drain discharge were key transport mechanisms with similar contributions of 53 and 47% of measured mass losses, respectively. Even if thiamethoxam was applied at a relatively low rate and had a low mass exportation value (0.3%), the relative toxicity was one to two orders of magnitude higher than those of the other chemicals applied in 2014 and 2015. Companion herbicides, except glyphosate in tile drains, exceeded their water quality guideline during one sampling campaign after

  18. Altitudinal and chiral signature of persistent organochlorine pesticides in air, soil, and spruce needles (Picea abies) of the Alps.

    Science.gov (United States)

    Shen, Heqing; Henkelmann, Bernhard; Levy, Walkiria; Zsolnay, Adam; Weiss, Peter; Jakobi, Gert; Kirchner, Manfred; Moche, Wolfgang; Braun, Katharina; Schramm, Karl-Werner

    2009-04-01

    The present study investigated the distribution, transportation, and biodegradation of the selected chiral persistent organochlorine pesticides (OCP) in the Alps. In the complex environment, we found the movement and fate of OCP could be defined by many factors. Taking HCE as an example, below the timberline its accumulation from air into SPMD increased with altitude and seasonally changed, but the trends reversed above the timberline. In soil, the tendency of HCE concentrations vs organic materials followed a sigmoid curve, and HCE concentration-altitude correlations are positive in central Alps but negative in southern Alps. The HCE enantiomeric ratios (ERs) in soil correlated to HCE isomers concentrations, the humus pH values, and the sampling site altitudes. HCE shift from humus to mineral soil can also be traced by ERs. The altitudinal and longitudinal trends in needles suggested that alpha-HCH has a more complex movementthan HCE in Alps. In conclusion, altitude conducted condensation, plant canopies, organic material in soil, and geographic specific precipitations may affect OCP distributions and transportation, whereas altitude conducted temperature and soil pH could dictate their fate in the environment.

  19. Investigation and Determination of Corn Combine Harvester Losses to Introduce Appropriate Methods to Reduce Losses

    Directory of Open Access Journals (Sweden)

    M.R Mostofi Sarkari

    2011-03-01

    Full Text Available Corn harvesting involves some losses. These losses result in decreased benefits. It is almost impossible to lower losses to zero percent but it can be controlled in an acceptable level. As a result of this research, appropriate methods are introduced to decrease losses and reduce waste. In this project, losses in different part of combine were measured and evaluated according to the available standard method (ASAE S396.2 & S343.3. Harvesting losses include preharvest and during harvest losses comprising ear loss and kernal loss in the header, cylinder and cleaning losses. This project was conducted on farmers’ lands in Gazvin province. Some assessments related to yield factors were evaluated in different parts of farm with specified area, e.g. Plant height, ear number, stem diameter, ear diameter, cob diameter, row/ear and seed/row. All losses evaluated in three treatments which they were: seed moisture content (w.b. in three levels of 19%, 23% and 27%, ground speed in three levels of 0.8, 1.2 and 1.6 ms-1 and cylinder speed of 400, 600 and 800 rpm. The split plot experimental design based on the randomised complete block design (RCBD was used to evaluate treatments. Measured losses compared with standard values to introduce the proper methods to decrease losses and proper adjustments. The results show that appropriate seed moisture content, cylinder and ground speed were 23%, 400 rpm and 1.2 ms-1, respectively. They had minimum total loss which WAS 1.55%, 2.65% and 2.34%, respectivily. The results also show that there was an ear loss in preharvest loss (because of bad weather condition that was 0.95-5.42%, also kernal loss on the header and cylinder loss which all related to improper adjustment of combine but total loss was in an acceptable level and standard. It was variable from 1.55% to 4.02%. Other parameters such as using inexperienced driver, improper combine adjustment, and also nonuniformity of field and ear moisture content in

  20. Concentrations of dissolved organic carbon along an altitudinal gradient from Norway spruce forest to the mountain birch/alpine ecotone in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, N.; Roesberg, I.; Aamlid, D.

    2005-07-01

    Concentrations of dissolved organic carbon (DOC) in soil water from the base of the soil organic layer were determined at three forest plots along an altitudinal gradient in eastern Norway. The lowest plot, at 830 m above sea level (a.s.l.), was in Norway spruce forest and there were additional plots at the ecotone between Norway spruce and mountain birch at 925 m a.s.l. and at the forest line (1000 m a.s.l.). DOC concentrations in soil water did not decrease uniformly with altitude although tree biomass, above-ground litterfall and the soil C pool all did so. Significant correlations between DOC and (H{sup +}) or electrical conductivity may reflect the contribution of DOC to solution acidity and the anionic charge, respectively. If mean temperature during the growing season increases, tree growth at any given altitude will tend to increase and the spruce-birch ecotone may move to a higher altitude than at present. Increased C inputs as litter to the soil might then lead to increasing DOC concentrations and fluxes in surface waters. (orig.)

  1. Auralization of vibroacoustic models in engineering using Wave Field Synthesis: Application to plates and transmission loss

    Science.gov (United States)

    Bolduc, A.; Gauthier, P.-A.; Berry, A.

    2017-12-01

    While perceptual evaluation and sound quality testing with jury are now recognized as essential parts of acoustical product development, they are rarely implemented with spatial sound field reproduction. Instead, monophonic, stereophonic or binaural presentations are used. This paper investigates the workability and interest of a method to use complete vibroacoustic engineering models for auralization based on 2.5D Wave Field Synthesis (WFS). This method is proposed in order that spatial characteristics such as directivity patterns and direction-of-arrival are part of the reproduced sound field while preserving the model complete formulation that coherently combines frequency and spatial responses. Modifications to the standard 2.5D WFS operators are proposed for extended primary sources, affecting the reference line definition and compensating for out-of-plane elementary primary sources. Reported simulations and experiments of reproductions of two physically-accurate vibroacoustic models of thin plates show that the proposed method allows for an effective reproduction in the horizontal plane: Spatial and frequency domains features are recreated. Application of the method to the sound rendering of a virtual transmission loss measurement setup shows the potential of the method for use in virtual acoustical prototyping for jury testing.

  2. Plant biodiversity patterns on Helan Mountain, China

    Science.gov (United States)

    Jiang, Yuan; Kang, Muyi; Zhu, Yuan; Xu, Guangcai

    2007-09-01

    A case study was conducted to mountainous ecosystems in the east side of Helan Mountain, located in the transitional zone between steppe and desert regions of China, aiming to reveal the influences of four environmental factors on features of plant biodiversity—the spatial pattern of vegetation types, and the variation of α- and β-diversities in vegetation and flora. Field surveys on vegetation and flora and on environmental factors were conducted, and those field data were analyzed through CCA (Canonical Correspondence Analysis), and through Shannon-Weiner index for α-diversity and Sørensen index for β-diversity. The preliminary results are: (1) Ranked in terms of their impacts on spatial patterns of plant biodiversity, the four selected environmental factors would be: elevation > location > slope > exposure. (2) The variation of Shannon-Weiner index along the altitudinal gradient is similar to that of species amount within altitudinal belts spanning 200 m each, which suggests a unimodal relationship between the species richness and the environmental condition with regards to altitudinal factors. Both the Shannon-Weiner index and the species richness within each altitudinal belt reach their maximum at elevation range from about 1700 to 2000 m a.s.l. (3) The altitudinal extent with the highest Shannon-Weiner index is identical to the range, where both the deciduous broad-leaved forest, and the temperate evergreen coniferous and deciduous broad-leaved mixed forest distribute. The altitudinal range from 1700 to 2200 m a.s.l. is the sector with both high level of species richness and diversified vegetation types. (4) The variation of β-diversity along the altitude is consistent with the vegetation vertical zones. According to the Sørensen index between each pair of altitudinal belts, the transition of vegetation spectrum from one zone to another, as from the base horizontal zone, the desert steppe, to the first vertical zone, the mountain open forest and

  3. Mass loss on the Asymptotic Giant Branch

    OpenAIRE

    Zijlstra, Albert

    2006-01-01

    Mass loss on the Asymptotic Giant Branch provides the origin of planetary nebulae. This paper reviews several relevant aspects of AGB evolution: pulsation properties, mass loss formalisms and time variable mass loss, evidence for asymmetries on the AGB, binarity, ISM interaction, and mass loss at low metallicity. There is growing evidence that mass loss on the AGB is already asymmetric, but with spherically symmetric velocity fields. The origin of the rings may be in pulsational instabilities...

  4. Functional visual fields: relationship of visual field areas to self-reported function.

    Science.gov (United States)

    Subhi, Hikmat; Latham, Keziah; Myint, Joy; Crossland, Michael D

    2017-07-01

    The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss. Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory. Greater visual field loss (0-60°) was associated with worse self-reported function both overall (R 2 = 0.50; p function (R 2 = 0.61, p function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R 2 = 0.56, p function in multiple regression analysis. Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0-30°) and peripheral (30-60°) mean threshold are good predictors of self-reported function, but the peripheral (30-0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  5. Loss models for long Josephson junctions

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1984-01-01

    A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement.......A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement....

  6. Electromagnetic field analyses of two-layer power transmission cables consisting of coated conductors with magnetic and non-magnetic substrates and AC losses in their superconductor layers

    International Nuclear Information System (INIS)

    Nakahata, Masaaki; Amemiya, Naoyuki

    2008-01-01

    Two-dimensional electromagnetic field analyses were undertaken using two representative cross sections of two-layer cables consisting of coated conductors with magnetic and non-magnetic substrates. The following two arrangements were used for the coated conductors between the inner and outer layers: (1) tape-on-tape and (2) alternate. The calculated magnetic flux profile around each coated conductor was visualized. In the case of the non-magnetic substrate, the magnetic field to which coated conductors in the outer layer are exposed contains more perpendicular component to the conductor wide face (perpendicular field component) when compared to that in the inner layer. On the other hand, for the tape-on-tape arrangement of coated conductors with a magnetic substrate, the reverse is true. In the case of the alternate arrangement of the coated conductor with a magnetic substrate, the magnetic field to which the coated conductors in the inner and outer layers are exposed experiences a small perpendicular field component. When using a non-magnetic substrate, the AC loss in the superconductor layer of the coated conductors in the two-layer cables is dominated by that in the outer layer, whereas the reverse is true in the case of a magnetic substrate. When comparing the AC losses in superconductor layers of coated conductors with non-magnetic and magnetic substrates in two-layer cables, the latter is larger than the former, but the influence of the magnetism of substrates on AC losses in superconductor layers is not remarkable

  7. Low ac loss geometries in YBCO coated conductors

    International Nuclear Information System (INIS)

    Duckworth, R.C.; List, F.A.; Paranthaman, M.P.; Rupich, M.W.; Zhang, W.; Xie, Y.Y.; Selvamanickam, V.

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders

  8. Low ac loss geometries in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, R.C. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States)], E-mail: duckworthrc@ornl.gov; List, F.A.; Paranthaman, M.P. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States); Rupich, M.W.; Zhang, W. [American Superconductor, Two Technology Drive, Westborough, MA 01581 (United States); Xie, Y.Y.; Selvamanickam, V. [SuperPower, 450 Duane Ave, Schenectady, NY 12304 (United States)

    2007-10-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders.

  9. Predicting AC loss in practical superconductors

    International Nuclear Information System (INIS)

    Goemoery, F; Souc, J; Vojenciak, M; Seiler, E; Klincok, B; Ceballos, J M; Pardo, E; Sanchez, A; Navau, C; Farinon, S; Fabbricatore, P

    2006-01-01

    Recent progress in the development of methods used to predict AC loss in superconducting conductors is summarized. It is underlined that the loss is just one of the electromagnetic characteristics controlled by the time evolution of magnetic field and current distribution inside the conductor. Powerful methods for the simulation of magnetic flux penetration, like Brandt's method and the method of minimal magnetic energy variation, allow us to model the interaction of the conductor with an external magnetic field or a transport current, or with both of them. The case of a coincident action of AC field and AC transport current is of prime importance for practical applications. Numerical simulation methods allow us to expand the prediction range from simplified shapes like a (infinitely high) slab or (infinitely thin) strip to more realistic forms like strips with finite rectangular or elliptic cross-section. Another substantial feature of these methods is that the real composite structure containing an array of superconducting filaments can be taken into account. Also, the case of a ferromagnetic matrix can be considered, with the simulations showing a dramatic impact on the local field. In all these circumstances, it is possible to indicate how the AC loss can be reduced by a proper architecture of the composite. On the other hand, the multifilamentary arrangement brings about a presence of coupling currents and coupling loss. Simulation of this phenomenon requires 3D formulation with corresponding growth of the problem complexity and computation time

  10. AC magnetic losses in Bi-2223/Ag tapes with different aspect ratios

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J.; Luo, X.M.; Chen, D.X.; Collings, E.W.; Lee, E.; Sumption, M.D.; Alamgir, A.K.M.; Yi, H.P.; Fang, J.G.; Gu, C.; Guo, S.Q.; Liu, M.L.; Xin, Y.; Han, Z

    2004-10-01

    AC losses in multi-filamentary tapes depend on various parameters. Among them, the overall tape width and thickness are expected to have an important influence. In order to study this geometrical effect, five Bi-2223/Ag tapes with different aspect ratios from 5 to 26 have been prepared. AC losses have been measured at 77 K when a perpendicular AC magnetic field is applied. It has been found that at any frequencies the magnetic loss per cycle increases as the aspect ratio increases. For AC magnetic loss, with increasing frequency from 3 to 9000 Hz the losses as a function of frequency show a maximum if the field amplitude is much less than the full penetration field or increase continuously if the field amplitude is larger.

  11. AC magnetic losses in Bi-2223/Ag tapes with different aspect ratios

    International Nuclear Information System (INIS)

    Fang, J.; Luo, X.M.; Chen, D.X.; Collings, E.W.; Lee, E.; Sumption, M.D.; Alamgir, A.K.M.; Yi, H.P.; Fang, J.G.; Gu, C.; Guo, S.Q.; Liu, M.L.; Xin, Y.; Han, Z.

    2004-01-01

    AC losses in multi-filamentary tapes depend on various parameters. Among them, the overall tape width and thickness are expected to have an important influence. In order to study this geometrical effect, five Bi-2223/Ag tapes with different aspect ratios from 5 to 26 have been prepared. AC losses have been measured at 77 K when a perpendicular AC magnetic field is applied. It has been found that at any frequencies the magnetic loss per cycle increases as the aspect ratio increases. For AC magnetic loss, with increasing frequency from 3 to 9000 Hz the losses as a function of frequency show a maximum if the field amplitude is much less than the full penetration field or increase continuously if the field amplitude is larger

  12. Toughness of the Virunga mountain gorilla (Gorilla beringei beringei) diet across an altitudinal gradient.

    Science.gov (United States)

    Glowacka, Halszka; McFarlin, Shannon C; Vogel, Erin R; Stoinski, Tara S; Ndagijimana, Felix; Tuyisingize, Deo; Mudakikwa, Antoine; Schwartz, Gary T

    2017-08-01

    The robust masticatory system of mountain gorillas is thought to have evolved for the comminution of tough vegetation, yet, compared to other primates, the toughness of the mountain gorilla diet is unremarkable. This may be a result of low plant toughness in the mountain gorilla environment or of mountain gorillas feeding selectively on low-toughness foods. The goal of this paper is to determine how the toughness of the mountain gorilla diet varies across their habitat, which spans a large altitudinal range, and whether there is a relationship between toughness and food selection by mountain gorillas. We collected data on the following variables to determine whether, and if so how, they change with altitude: leaf toughness of two plant species consumed by mountain gorillas, at every 100 m increase in altitude (2,600-3,700 m); toughness of consumed foods comprising over 85% of the gorilla diet across five vegetation zones; and toughness of unconsumed/infrequently consumed plant parts of those foods. Although leaf toughness increased with altitude, the toughness of the gorilla diet remained similar. There was a negative relationship between toughness and consumption frequency, and toughness was a better predictor of consumption frequency than plant frequency, biomass, and density. Consumed plant parts were less tough than unconsumed/infrequently consumed parts and toughness of the latter increased with altitude. Although it is unclear whether gorillas select food based on toughness or use toughness as a sensory cue to impart other plant properties (e.g., macronutrients, chemicals), our results that gorillas maintain a consistent low-toughness dietary profile across altitude, despite toughness increasing with altitude, suggest that the robust gorilla masticatory apparatus evolved for repetitive mastication of foods that are not high in toughness. © 2017 Wiley Periodicals, Inc.

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

    Energy Technology Data Exchange (ETDEWEB)

    Saha, S.; Rajwar, G.S.; Kumar, M.

    2016-07-01

    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. (Author)

  14. Plasma microinstabilities driven by loss-cone distributions

    International Nuclear Information System (INIS)

    Summers, D.; Thorne, R.M.

    1995-01-01

    Electromagnetic and electrostatic instabilities driven by loss-cone particle distributions have been invoked to explain a variety of plasma phenomena observed in space and in the laboratory. In this paper we analyse how the loss-cone feature (as determined by the loss-cone index or indices) influences the growth of such instabilities in a fully ionized, homogeneous, hot plasma in a uniform magnetic field. Specifically, we consider three loss-cone distributions: a generalized Lorentzian (kappa) loss-cone distribution, the Dory-Guest-Harris distribution and the Ashour-Abdalla-Kennel distribution (involving a subtracted Maxwellian). Our findings are common to all three distributions. We find that, for parallel propagation, electromagnetic instabilities are only affected by the loss-cone indices in terms of their occurrence in the temperature anisotropy. However, for oblique propagation, even including propagation at small angles to the ambient magnetic field, the loss-cone indices do independently affect the growth of instabilities for electromagnetic waves, in contrast to certain claims in the literature. For electrostatic waves such that 1/2(κ perpendicular to ρ L σ 2 L σ is the Larmor radius for particle species σ, we find that the loss-cone indices only enter the dispersion equation via the temperature anisotropy, and so in this case the loss-cone feature and perpendicular effective thermal speed do not independently affect wave growth. (Author)

  15. Efeito do gradiente altitudinal/latitudinal sobre espécies de aves florestais da família Furnariidae na Bacia do Rio Tibagi, Paraná, Brasil Effect of altitudinal/latitudinal gradient about forest ovenbirds species (Aves: Furnariidae in the Tibagi river basin, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Fernando de L. Fávaro

    2006-03-01

    Full Text Available Variações na riqueza e abundância de Furnariidae florestais foram analisadas ao longo do gradiente altitudinal/latitudinal da bacia do rio Tibagi (BRT, Paraná, Brasil. A Floresta Ombrófila Mista (1060 m a.n.m. é a formação dominante no sul da BRT, enquanto que a Floresta Estacional Semidecidual (298 m a.n.m., ocorre no norte. O número total de espécies obtidas na BRT foi 14. A riqueza e a abundância de Furnariidae foram maiores no sul (12 espécies, IPA = 2,01 do que no norte (cinco espécies, IPA = 0,45 da BRT. As similaridades também foram altas entre o sul e o centro da BRT. A estrutura da comunidade de Furnariidae também apresentou correlação positiva entre o sul e o centro da BRT (coeficiente de correlação por postos de Spearman; r s = 0,96, r s = 0,89, r s = 1,00. As relações evolutivas de alguns representantes de Furnariidae com o sul da América do Sul e com os Andes podem explicar a maior presença desta família no sul da BRT. Um outro aspecto que também pode ajudar a explicar os resultados apresentados por Furnariidae são as semelhanças entre a Floresta Ombrófila Mista do sul da BRT e outras florestas temperadas da América do Sul.Variations in richness and abundance of forest ovenbirds (Aves: Furnariidae were studied along an altitudinal/latitudinal gradient of the Tibagi river basin (TRB, southern Brazil. Mixed Temperate Rain Forest (1060 m a.s.l. is the dominant forest in the southern TRB while Seasonal Semideciduous Forest (298 m a.s.l. occurs in the northern. The total number of species obtained in the TRB was 14. Richness and Abundance of Furnariidae were greater in the southern (12 species, IPA = 2.01 than in the northern (five species, IPA = 0.45 TRB. Similarities were also greatest in the southern and in the middle TRB. The community structure of Furnariidae also presented a positive correlation between the southern and the middle TRB (Spearman's rank correlation coefficient; r s = 0.96, r s = 0.89, r s

  16. Thin minimal rim width at Bruch’s membrane opening is associated with glaucomatous paracentral visual field loss

    Directory of Open Access Journals (Sweden)

    Taniguchi EV

    2017-12-01

    Full Text Available Elise V Taniguchi,1–3 Eleftherios I Paschalis,1,2 Dejiao Li,1,4 Kouros Nouri-Mahdavi,5 Stacey C Brauner,1 Scott H Greenstein,1 Angela V Turalba,1 Janey L Wiggs,1 Louis R Pasquale,1,6 Lucy Q Shen1 1Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear, Boston, MA, 2Boston Keratoprosthesis Laboratory, Massachusetts Eye and Ear – Schepens Eye Research Institute, Harvard Medical School, Boston, MA, USA; 3Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, Brazil; 4Department of Ophthalmology, Beijing China-Japan Friendship Hospital, Beijing, People’s Republic of China; 5Department of Ophthalmology, David Geffen School of Medicine and Stein Eye Institute, Los Angeles, CA, USA; 6Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA Purpose: To compare optic nerve head (ONH measurements in glaucomatous eyes with paracentral visual field (VF loss to eyes with peripheral VF loss and controls.Methods: Open-angle glaucoma (OAG patients with early paracentral VF loss or isolated peripheral VF loss as well as control subjects underwent ONH imaging with swept-source optical coherence tomography (OCT and retinal nerve fiber layer (RNFL imaging with spectral-domain OCT. Minimum rim width at Bruch’s membrane opening (BMO-MRW, lamina cribrosa depth (LCD, and RNFL thickness were compared among the glaucoma and control groups with one-way analysis of variance, Kruskal–Wallis test, and multiple regression analysis.Results: Twenty-nine eyes from 29 OAG patients (15 early paracentral and 14 isolated peripheral VF loss and 20 eyes of 20 control subjects were included. The early paracentral and isolated peripheral VF loss groups had similar VF mean deviation (MD (–5.3±2.7 dB and –3.7±3.0 dB, p=0.15, respectively. Global BMO-MRW was lower in OAG eyes than in controls (193.8±40.0 vs 322.7±62.2 µm, p<0.001, but similar

  17. Hemoglobin function and allosteric regulation in semi-fossorial rodents (family Sciuridae) with different altitudinal ranges

    Science.gov (United States)

    Revsbech, Inge G.; Tufts, Danielle M.; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E.; Storz, Jay F.; Fago, Angela

    2013-01-01

    SUMMARY Semi-fossorial ground squirrels face challenges to respiratory gas transport associated with the chronic hypoxia and hypercapnia of underground burrows, and such challenges are compounded in species that are native to high altitude. During hibernation, such species must also contend with vicissitudes of blood gas concentrations and plasma pH caused by episodic breathing. Here, we report an analysis of hemoglobin (Hb) function in six species of marmotine ground squirrels with different altitudinal distributions. Regardless of their native altitude, all species have high Hb–O2 affinities, mainly due to suppressed sensitivities to allosteric effectors [2,3-diphosphoglycerate (DPG) and chloride ions]. This suppressed anion sensitivity is surprising given that all canonical anion-binding sites are conserved. Two sciurid species, the golden-mantled and thirteen-lined ground squirrel, have Hb–O2 affinities that are characterized by high pH sensitivity and low thermal sensitivity relative to the Hbs of humans and other mammals. The pronounced Bohr effect is surprising in light of highly unusual amino acid substitutions at the C-termini that are known to abolish the Bohr effect in human HbA. Taken together, the high O2 affinity of sciurid Hbs suggests an enhanced capacity for pulmonary O2 loading under hypoxic and hypercapnic conditions, while the large Bohr effect should help to ensure efficient O2 unloading in tissue capillaries. In spite of the relatively low thermal sensitivities of the sciurid Hbs, our results indicate that the effect of hypothermia on Hb oxygenation is the main factor contributing to the increased blood–O2 affinity in hibernating ground squirrels. PMID:24172889

  18. Characteristics of possible beam losses in superconducting cyclotron

    International Nuclear Information System (INIS)

    Pradhan, J.; Paul, Santanu; Debnath, Jayanta; Dutta, Atanu; Bhunia, Uttam; Naser, Md. Zamal Abdul; Singh, Vinay; Agrawal, Ankur; Dey, Malay Kanti

    2015-01-01

    In a compact superconducting cyclotron large coherent oscillation and off-centering of the beam may cause large amount of beam loss. The off-centered beam may hit the beam chamber wall prohibiting extraction of the beam. Or it may hit the RF liner surfaces due to vertical blow-up across various resonances during acceleration. The vertical shift of beam caused by the mis-alignment gradually moves the beam out of geometrical median plane eventually leading to internal beam losses. The loss of isochronisms results the reduction of beam intensity depending on the particle phase history. Small field perturbations generated by trim coils have been used to identify the beam loss mechanisms in the superconducting cyclotron at out centre. Besides, the beam loss due to interaction of accelerating ions with residual gases is also discussed. The beam profile obtained from differential and three finger probes gives a clear insight of the loss-mechanism. The paper describes different beam losses observed in the cyclotron with corresponding beam profiles under different field perturbations, Special emphasis is given on characteristics features of beam-current profile to identify the cause of beam loss. (author)

  19. Functional vision loss: a diagnosis of exclusion.

    Science.gov (United States)

    Villegas, Rex B; Ilsen, Pauline F

    2007-10-01

    Most cases of visual acuity or visual field loss can be attributed to ocular pathology or ocular manifestations of systemic pathology. They can also occasionally be attributed to nonpathologic processes or malingering. Functional vision loss is any decrease in vision the origin of which cannot be attributed to a pathologic or structural abnormality. Two cases of functional vision loss are described. In the first, a 58-year-old man presented for a baseline eye examination for enrollment in a vision rehabilitation program. He reported bilateral blindness since a motor vehicle accident with head trauma 4 years prior. Entering visual acuity was "no light perception" in each eye. Ocular health examination was normal and the patient made frequent eye contact with the examiners. He was referred for neuroimaging and electrophysiologic testing. The second case was a 49-year-old man who presented with a long history of intermittent monocular diplopia. His medical history was significant for psycho-medical evaluations and a diagnosis of factitious disorder. Entering uncorrected visual acuities were 20/20 in each eye, but visual field testing found constriction. No abnormalities were found that could account for the monocular diplopia or visual field deficit. A diagnosis of functional vision loss secondary to factitious disorder was made. Functional vision loss is a diagnosis of exclusion. In the event of reduced vision in the context of a normal ocular health examination, all other pathology must be ruled out before making the diagnosis of functional vision loss. Evaluation must include auxiliary ophthalmologic testing, neuroimaging of the visual pathway, review of the medical history and lifestyle, and psychiatric evaluation. Comanagement with a psychiatrist is essential for patients with functional vision loss.

  20. MPO-type single-mode multi-fiber connector: Low-loss and high-return-loss intermateability of APC-MPO connectors

    Science.gov (United States)

    Satake, Toshiaki; Nagasawa, Shinji; Hughes, Mike; Lutz, Sharon

    2011-01-01

    The electrical communication laboratory of NTT started the research of MT (Mechanically Transferable) connector in early 1980s. The initial goal was to realize a multi-fiber connector which can repeat low loss, stable, reliable and low-cost connections of subscriber optical fiber cable networks for more than 20 years period in the field. We review the multi-fiber alignment design with two guide pins, and following several technical improvements toward the final MT connector used in the commercial telecommunication networks. And then, we review development histories to reach to the low-loss, high-return-loss and reliable APC-MPO (Angled Physical Contact Multi-fiber Push On) connectors introduced in NTT COs and in Verizon's FTTH (Fiber To The Home) networks. In the latter half, we propose the low-loss intermateability design for connectors made by different suppliers in order to enable mass introductions into large scale systems. In addition we also describe an accurate connector loss presumption method for different lots' ferrules based on the MT ferrule dimension data before assembling the connectors. We believe with a wide intermateability of APC-MPO connector will increase its use in the fields. The APC-MPO connector manufactured based on the proposed design had low insertion losses of less than 0.25 dB at the same level of simplex connectors and the higher level of return losses higher than 65 dB.

  1. Carrot Loss during Primary Production : Field Waste and Pack House Waste.

    OpenAIRE

    Bond, Rebekka

    2016-01-01

    Background: it has been suggested that roughly one-third of all food produced for human consumption is lost or wasted globally. The reduction of loss and waste is seen as an important societal issue with considerable ethical, ecological and economic implications. Fruit and vegetables have the highest wastage rates of any food products; (45 %). And a big part of this waste occurs during production, but empirical data on loss during primary production is limited. Carrots are an important hortic...

  2. Evaluation of a cryostable low-loss conductor for pulsed field applications

    International Nuclear Information System (INIS)

    Wollan, J.J.; Walker, M.S.; Zeitlin, B.A.; Pollack, D.A.; Shen, S.S.

    1980-01-01

    A cryostable, low loss conductor as the basic strand in a 50 kA cable for a 20 MJ prototype, tokamak induction heating coil has been developed, fabricated, and evaluated. The conductor has a copper matrix multifilamentary NbTi core surrounded by a CuNi ring and stabilizing copper segmented by radial CuNi fins. Pulsed loss measurements have been made up to 2.2 T and for decay times from 0.7 to 278 ms. Measurements made on samples with various twists and portions etched away have allowed accurate evaluation of the loss components. Stability measurements were also made on insulated and uninsulated single strands and on subcables. Measured recovery heat flux for the bare strand is about 0.3 W/cm 2 ; however, the application of a 0.0005 in. layer of Omega insulation increases the value to about 0.5 W/cm 2

  3. Improved loss calculations for the HDM magnets

    International Nuclear Information System (INIS)

    Mallick, G.T. Jr.; Carr, W.J.; Krefta, M.P.; Johnson, D.

    1994-01-01

    Losses due to ramped fields and currents, quite adequate for the initial design, were calculated previously by Snitchler, Jayakumar, Kovachev, and Orrell for the high energy booster magnets to be used in the SSC. The present analysis considers the loss problem in more detail

  4. Magnetic losses of commercial REBCO coated conductors in the low frequency range

    Science.gov (United States)

    De Marzi, G.; Iannone, G.; Gambardella, U.

    2018-05-01

    We have investigated the frequency dependence of the magnetic losses of different 2 G commercial REBCO coated-conductor tapes in the low frequency range ∼1–10 mHz of applied magnetic field at 5 and 77 K. We explored high field range, well above the penetration field, with fields applied perpendicularly to the flat surface. We found that the in-field hysteresis losses increase with increasing frequencies in all the investigated high-temperature superconductor (HTS) tapes, following a power-law dependence. An electromagnetic 2D finite element method model, based on H-formulation, has also been implemented, in which the frequency dependence of the hysteretic loss is computed taking into account the measured power-law E(J) characteristic for the electric field, and the experimental J c(B). Experimental and numerical findings are in very good agreement, so an extrapolation to higher ramp rate values is possible, thus providing a useful basis for the assessment of the hysteresis losses in fusion and accelerator HTS magnets.

  5. Amygdala damage eliminates monetary loss aversion.

    Science.gov (United States)

    De Martino, Benedetto; Camerer, Colin F; Adolphs, Ralph

    2010-02-23

    Losses are a possibility in many risky decisions, and organisms have evolved mechanisms to evaluate and avoid them. Laboratory and field evidence suggests that people often avoid risks with losses even when they might earn a substantially larger gain, a behavioral preference termed "loss aversion." The cautionary brake on behavior known to rely on the amygdala is a plausible candidate mechanism for loss aversion, yet evidence for this idea has so far not been found. We studied two rare individuals with focal bilateral amygdala lesions using a series of experimental economics tasks. To measure individual sensitivity to financial losses we asked participants to play a variety of monetary gambles with possible gains and losses. Although both participants retained a normal ability to respond to changes in the gambles' expected value and risk, they showed a dramatic reduction in loss aversion compared to matched controls. The findings suggest that the amygdala plays a key role in generating loss aversion by inhibiting actions with potentially deleterious outcomes.

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

    Directory of Open Access Journals (Sweden)

    Zeinab Toluei

    2010-07-01

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

  7. 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.

  8. Losses in German nuclear power plants

    International Nuclear Information System (INIS)

    Abinger, R.

    1982-01-01

    The author illustrates the special features of engineering insurance for nuclear power plants. The shares of the Allianz Versicherungs-AG in the insurance of construction and erection work and in machinery insurance are dealt with. Risk estimation is usually based on statistical analysis of losses. Loss analysis in the conventional sector of nuclear power plants shows typical characteristics of traditional erection and machinery losses. In the nuclear field, however, costs are greatly increased by added safety measures. For this reason, additional cover is allocated and incorporated in premium assessment. Examples from erection and machinery reveal the greater costs involved in handling losses. (orig.) [de

  9. Loss-cone-driven ion cyclotron waves in the magnetosphere

    International Nuclear Information System (INIS)

    Denton, R.E.; Hudson, M.K.; Roth, I.

    1992-01-01

    The theoretical properties of linear ion cyclotron waves propagating in the magnetosphere at arbitrary angles to the background magnetic field are explored. It is found that in some cases the linear wave growth of modes with oblique propagation can dominate that of the parallel propagating electromagnetic ion cyclotron (EMIC) wave. In particular, when the hot ring current protons have a loss cone and their temperature anisotropy A ≡ T perpendicular /T parallel - 1 is reduced, the parallel propagating EMIC wave becomes stable, while the obliquely propagating loss-cone-driven mode persists. The growth rate of the loss-cone-driven model depends strongly on the depth of the loss cone. Unlike the parallel propagating EMIC wave, it can be unstable with A = 0. Other conditions that favor the loss-cone-driven mode in comparison to the parallel mode are stronger background magnetic field, lower density of cold hydrogen, and a lower temperature for the hot anisotropic component of hydrogen. A simple analytical theory is presented which explains the scaling of the growth rate of the oblique mode with respect to various parameters. The loss-cone-driven mode is an electromagnetic mode which is preferentially nearly linearly polarized. It is nearly electrostatic in the sense that the wave electric field is aligned with the perpendicular (to B 0 ) component of the wave vector k and k perpendicular > k parallel . Since the electric and magnetic wave fields are perpendicular to B 0 , they would be difficult to distinguish from those of a linearly polarized parallel propagating electromagnetic wave with the same k parallel

  10. The rotational hysteresis losses in thin films with unidirectional magnetic anisotropy

    Science.gov (United States)

    Mucha, J. M.; Vatskichev, L.; Vatskicheva, M.

    1992-03-01

    Using the Planar Hall Effect (PHE) the rotational hysteresis losses in NiFeGe thin magnetic films were measured. The calculation of the critical field for magnetization and rotational hysteresis losses based on extended Stoner-Wohlfarth theory including an exchange magnetic field is given.

  11. Extension to AC Loss Minimisation in High Temperature Superconductors

    National Research Council Canada - National Science Library

    Campbell, Archie

    2004-01-01

    ...: (a) Measure the AC losses of appropriate Yttrium Barium Copper Oxide (YBCO) samples with strong potential for minimizing losses at high frequencies and magnetic fields with the existing equipment. (b...

  12. Ac losses of transposed superconductors

    International Nuclear Information System (INIS)

    Eckert, D.; Enderlein, G.; Lange, F.

    1975-01-01

    Eastham and Rhodes published results of loss measurements on transposed superconducting NbTi cables and concluded basing on an extrapolation to very large numbers of wires that transposed superconductors could be used favorably in cables for power transmission. There are some reasons to question the correctness of their extrapolation. Losses were calculated for transposed superconductors in self field and got results different from those of Eastham and Rhodes. Loss measurements were performed the results of which give evidence for the correctness of our calculations. The results lead to the conclusion that the use of transposed cables of irreversible type 2 superconductors for power transmission is not advantageous

  13. Adiabatic-drift-loss modification of the electromagnetic loss-cone instability for anisotropic plasma

    International Nuclear Information System (INIS)

    Juhl, B.; Treumann, R.A.

    1980-01-01

    Observation of the adiabatic behaviour of energetic particle pitch-angle distributions in the magnetosphere (Lyons, 1977, and others) in the past indicated the development of pronounced minima or drift-loss cones on the pitch-angle distributions centred at α approx.= 90 0 in connection with storm-time changes in magnetospheric convection and magnetic field. Using a model of a drift-modified loss-cone distribution (MLCD) of the butterfly type, the linear stability of electromagnetic whistler or ion-cyclotron waves propagating parallel to the magnetic field has been investigated. The instability is shown to be quenched at high frequencies ω 0 are identified as generating electromagnetic cyclotron waves near the marginally stable frequency ωsub(m). It is concluded that the absence of electromagnetic VLF and ELF noise during times when MLCD develops is the result of the shift of the unstable spectrum to low frequencies. (orig.)

  14. Effect of air flow, panel curvature, and internal pressurization on field-incidence transmission loss

    Science.gov (United States)

    Koval, L. R.

    1976-01-01

    In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. Flow is shown to provide a modest increase in TL that is uniform with frequency up to the critical frequency. The increase is about 2 dB at Mach number M = 0.5, and about 3.5 dB at M = 1. Above the critical frequency where TL is damping controlled, the increase can be slightly larger at certain frequencies. Curvature is found to stiffen the panel, thereby increasing the TL at low frequencies, but also to introduce a dip at the 'ring frequency' of a full cylinder having the same radius as the panel. Pressurization appears to produce a slight decrease in TL throughout the frequency range, and also slightly shifts the dips at the critical frequency and at the ring frequency.

  15. Loss of ions in cavity ionization chambers

    International Nuclear Information System (INIS)

    Takata, N.; Tran, N.T.; Kim, E.; Marsoem, P.; Kurosawa, T.; Koyama, Y.

    2005-01-01

    Ion losses due to initial recombination, volume recombination, and back diffusion were each determined by measurements and calculations for different size cylindrical ionization chambers and spherical ionization chambers. By measuring signal currents from these ionization chambers irradiated with 60 Co gamma rays, two groups of ion losses were obtained. (Group 1) Ion loss due to initial recombination and diffusion, which changes proportionally to the inverse of the voltage applied to the ionization chambers; (and group 2) ion loss due to volume recombination, which changes proportionally to the inverse of the square of the applied voltage. The diffusion loss was obtained separately by computing electric field distributions in the ionization chambers. It was found that diffusion loss is larger than initial recombination loss for the cylindrical ionization chambers and vise versa for the spherical ionization chambers

  16. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

    Science.gov (United States)

    Kotas, Petr; Šantrůčková, Hana; Elster, Josef; Kaštovská, Eva

    2018-03-01

    The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  17. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    P. Kotas

    2018-03-01

    Full Text Available The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS, and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs. We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects, mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  18. MEASUREMENT OF RF LOSSES DUE TO TRAPPED FLUX IN A LARGE-GRAIN NIOBIUM CAVITY

    International Nuclear Information System (INIS)

    Gianluigi Ciovati; Alex Gurevich

    2008-01-01

    Trapped magnetic field in superconducting niobium is a well known cause of radio-frequency (RF) residual losses. In this contribution, we present the results of RF tests on a single-cell cavity made of high-purity large grain niobium before and after allowing a fraction of the Earth's magnetic field to be trapped in the cavity during the cooldown below the critical temperature Tc. This experiment has been done on the cavity before and after a low temperature baking. Temperature mapping allowed us to determine the location of hot-spots with high losses and to measure their field dependence. The results show not only an increase of the low-field residual resistance, but also a larger increase of the surface resistance for intermediate RF field (higher ''medium field Qslope''), which depends on the amount of the trapped flux. These additional field-dependent losses can be described as losses of pinned vortices oscillating under the applied RF magnetic field

  19. Assessment of the Bordas-Carnot Losses within the diffuser of tidal turbines using far-field and near-field CFD models.

    Science.gov (United States)

    Hajaali, Arthur

    2017-04-01

    This project has for ambition to analyse and further the general understanding on cross-flows interactions and behaviours at the mouth of a mini/small tidal hydropower plant and a river. Although, the study of these interactions could benefit and find applications in multiple hydraulic problems, this project concentrates its focus on the influence of the transposed turbulences generated by the cross-flow into the diffuser. These eddies affect the overall performance and efficiency of the bulb-turbines by minimizing the pressure recovery. In the past, these turbulences were accounted with the implementation of the Bordas-Carnot losses coefficient for the design of tidal project using bulb-turbines. The bulb turbine technology has been the interest and subject of many scientific papers but most of them concentrate and narrow their focus on the design of the rotor, blades and combiner. This project wants to focus the design of the diffuser by performing an analysis on the development of eddies and the turbulences using computational fluid dynamic (CFD) models. The Severn estuary is endowed with one of the highest tidal range around the hemisphere. The first part of the research requires to select case studies sites such as Briton-Ferry to virtually design mini-tidal plant in 0-Dimentional (D), 2D and 3D modelling to study development and behaviour of turbulences within the diffuser. The far-field model represents the marine environment prior and after the structure where bulb turbines are located. The near-field modelling has allowed researcher to study at much higher resolution and precision the design of a single turbine feeding model with predetermined and fix boundary condition. For this reason, a near-field model is required to study in depth the behaviour and evolution of the turbulence with the diffuser. One of the main challenge and advancement of this research is to find a methodology and system to link the far-field and near-field modelling to produce an

  20. Evaluation of Iron Loss in Interior Permanent Magnet Synchronous Motor with Consideration of Rotational Field

    Science.gov (United States)

    Ma, Lei; Sanada, Masayuki; Morimoto, Shigeo; Takeda, Yoji; Kaido, Chikara; Wakisaka, Takeaki

    Loss evaluation is an important issue in the design of electrical machines. Due to the complicate structure and flux distribution, it is difficult to predict the iron loss in the machines exactly. This paper studies the iron loss in interior permanent magnet synchronous motors based on the finite element method. The iron loss test data of core material are used in the fitting of the hysteresis and eddy current loss constants. For motors in practical operation, additional iron losses due to the appearance of rotation of flux density vector and harmonic flux density distribution makes the calculation data deviates from the measured ones. Revision is made to account for these excess iron losses which exist in the practical operating condition. Calculation results show good consistence with the experimental ones. The proposed method provides a possible way to predict the iron loss of the electrical machine with good precision, and may be helpful in the selection of the core material which is best suitable for a certain machine.

  1. Hysteresis losses of magnetic nanoparticle powders in the single domain size range

    International Nuclear Information System (INIS)

    Dutz, S.; Hergt, R.; Muerbe, J.; Mueller, R.; Zeisberger, M.; Andrae, W.; Toepfer, J.; Bellemann, M.E.

    2007-01-01

    Magnetic iron oxide nanoparticle powders were investigated in order to optimise the specific hysteresis losses for biomedical heating applications. Different samples with a mean particle size in the transition range from superparamagnetic to ferromagnetic behaviour (i.e. 10-100 nm) were prepared by two different chemical precipitation routes. Additionally, the influence of milling and annealing on hysteresis losses of the nanoparticles was investigated. Structural investigations of the samples were carried out by X-ray diffraction, measurement of specific surface area, and scanning and transmission electron microscopy. The dependence of hysteresis losses of minor loops on the field amplitude was determined using vibrating sample magnetometry and caloric measurements. For small field amplitudes, a power law was found which changes into saturation at amplitudes well above the coercive field. Maximum hysteresis losses of 6.6 J/kg per cycle were observed for milled powder. For field amplitudes below about 10 kA/m, which are especially interesting for medical and technical applications, hysteresis losses of all investigated powders were at least by one order of magnitude lower than reported for magnetosomes of comparable size

  2. Visual attention measures predict pedestrian detection in central field loss: a pilot study.

    Science.gov (United States)

    Alberti, Concetta F; Horowitz, Todd; Bronstad, P Matthew; Bowers, Alex R

    2014-01-01

    The ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT) and static attention (Useful Field of View; UFOV) were predictive of the ability of people with central field loss (CFL) to detect pedestrian hazards in simulated driving. 11 people with bilateral CFL (visual acuity 20/30-20/200) and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT) and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests). Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision). UFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse) (84% and 97%, respectively; p = 0.001). For CFL participants, higher proportions of timely reactions correlated significantly with higher (better) MOT speed thresholds (r = 0.73, p = 0.01), with better performance on the UFOV divided and selective attention subtests (r = -0.66 and -0.62, respectively, pattention may provide useful measures of functional visual ability of individuals with CFL relevant to more complex mobility tasks.

  3. 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.

  4. 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.

  5. GENERAL P, TYPE-I S, AND TYPE-II S WAVES IN ANELASTIC SOLIDS; INHOMOGENEOUS WAVE FIELDS IN LOW-LOSS SOLIDS.

    Science.gov (United States)

    Borcherdt, Roger D.; Wennerberg, Leif

    1985-01-01

    The physical characteristics for general plane-wave radiation fields in an arbitrary linear viscoelastic solid are derived. Expressions for the characteristics of inhomogeneous wave fields, derived in terms of those for homogeneous fields, are utilized to specify the characteristics and a set of reference curves for general P and S wave fields in arbitrary viscoelastic solids as a function of wave inhomogeneity and intrinsic material absorption. The expressions show that an increase in inhomogeneity of the wave fields cause the velocity to decrease, the fractional-energy loss (Q** minus **1) to increase, the deviation of maximum energy flow with respect to phase propagation to increase, and the elliptical particle motions for P and type-I S waves to approach circularity. Q** minus **1 for inhomogeneous type-I S waves is shown to be greater than that for type-II S waves, with the deviation first increasing then decreasing with inhomogeneity. The mean energy densities (kinetic, potential, and total), the mean rate of energy dissipation, the mean energy flux, and Q** minus **1 for inhomogeneous waves are shown to be greater than corresponding characteristics for homogeneous waves, with the deviations increasing as the inhomogeneity is increased for waves of fixed maximum displacement amplitude.

  6. Near-field characterization of low-loss photonic crystal waveguides

    DEFF Research Database (Denmark)

    Volkov, V. S.; Bozhevolnyi, S. I.; Borel, Peter Ingo

    2005-01-01

    -nm-period lattices with different filling factors (0.76 and 0.82) and connected to access ridge waveguides. Using the near-field optical images we investigate the light propagation along PCWs for TM and TE polarization (the electric field is perpendicular/parallel to the sample surface). Efficient...

  7. Atom loss resonances in a Bose-Einstein condensate.

    Science.gov (United States)

    Langmack, Christian; Smith, D Hudson; Braaten, Eric

    2013-07-12

    Atom loss resonances in ultracold trapped atoms have been observed at scattering lengths near atom-dimer resonances, at which Efimov trimers cross the atom-dimer threshold, and near two-dimer resonances, at which universal tetramers cross the dimer-dimer threshold. We propose a new mechanism for these loss resonances in a Bose-Einstein condensate of atoms. As the scattering length is ramped to the large final value at which the atom loss rate is measured, the time-dependent scattering length generates a small condensate of shallow dimers coherently from the atom condensate. The coexisting atom and dimer condensates can be described by a low-energy effective field theory with universal coefficients that are determined by matching exact results from few-body physics. The classical field equations for the atom and dimer condensates predict narrow enhancements in the atom loss rate near atom-dimer resonances and near two-dimer resonances due to inelastic dimer collisions.

  8. Basic principles of ultrafast Raman loss spectroscopy

    Indian Academy of Sciences (India)

    field tries to drive the electron with its frequency. If the applied field is of the form E = E0eiωt , the driving ..... (CARS),8 coherent Stokes Raman scattering (CSRS), ... gain or loss process in which only two beams are required and it is a self ...

  9. Terminology for pregnancy loss prior to viability

    DEFF Research Database (Denmark)

    Kolte, A M; Bernardi, L A; Christiansen, O B

    2015-01-01

    Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from...... different centres. In our opinion, terminology and definitions should be based on clinical findings, and when possible, transvaginal ultrasound. With this Early Pregnancy Consensus Statement, it is our goal to provide clear and consistent terminology for pregnancy loss prior to viability....

  10. Hysteresis losses in iron oxide nanoparticles prepared by glass crystallization or wet chemical precipitation

    International Nuclear Information System (INIS)

    Mueller, Robert; Dutz, Silvio; Hergt, Rudolf; Schmidt, Christopher; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    2007-01-01

    Ferrofluids were prepared from glass crystallized as well as wet precipitated iron oxide particles. Comparing hysteresis losses versus applied field amplitude from particles in immobilized state (powder) and in fluid state (ferrofluid) shows in some cases anomalous large losses at low magnetic fields. The influence of texture on the losses was investigated

  11. Acute Zonal Cone Photoreceptor Outer Segment Loss.

    Science.gov (United States)

    Aleman, Tomas S; Sandhu, Harpal S; Serrano, Leona W; Traband, Anastasia; Lau, Marisa K; Adamus, Grazyna; Avery, Robert A

    2017-05-01

    The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if

  12. Effects of Hypotensive Anesthesia on Reducing Intraoperative Blood Loss, Duration of Operation, and Quality of Surgical Field During Orthognathic Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Lin, Susie; McKenna, Samuel J; Yao, Chuan-Fong; Chen, Yu-Ray; Chen, Chit

    2017-01-01

    The objective of this study was to evaluate the efficacy of hypotensive anesthesia in reducing intraoperative blood loss, decreasing operation time, and improving the quality of the surgical field during orthognathic surgery. A systematic review and meta-analysis of randomized controlled trials addressing these issues were carried out. An electronic database search was performed. The risk of bias was evaluated with the Jadad Scale and Delphi List. The inverse variance statistical method and a random-effects model were used. Ten randomized controlled trials were included for analysis. Our meta-analysis indicated that hypotensive anesthesia reduced intraoperative blood loss by a mean of about 169 mL. Hypotensive anesthesia was not shown to reduce the operation time for orthognathic surgery, but it did improve the quality of the surgical field. Subgroup analysis indicated that for blood loss in double-jaw surgery, the weighted mean difference favored the hypotensive group, with a reduction in blood loss of 175 mL, but no statistically significant reduction in blood loss was found for anterior maxillary osteotomy. If local anesthesia with epinephrine was used in conjunction with hypotensive anesthesia, the reduction in intraoperative blood loss was increased to 254.93 mL. Hypotensive anesthesia was effective in reducing blood loss and improving the quality of the surgical field, but it did not reduce the operation time for orthognathic surgery. The use of local anesthesia in conjunction with hypotensive general anesthesia further reduced the amount of intraoperative blood loss for orthognathic surgery. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  13. Monitoring losses of copper based wood preservatives in the Thames estuary

    International Nuclear Information System (INIS)

    Hingston, J.A.; Murphy, R.J.; Lester, J.N.

    2006-01-01

    Field trials were conducted at two sites in the Thames estuary to monitor losses of copper, chromium and arsenic from wood preservative treated timbers of varying sizes and treatment regimes. Results indicated that leaching tests conducted under standard laboratory conditions might overestimate losses compared to losses resulting from real environmental exposures. Amine copper treated wood was noted to leach higher levels of copper compared to chromated copper arsenate treated wood, and was therefore considered an inappropriate replacement biocide for fresh and marine construction purposes on this basis. Increases in copper concentrations in the outer sections of amine copper treated posts may have represented re-distribution of this component in this timber. No accumulation of metals was found in sediments surrounding field trial posts. - Wood preservative field trials in the UK indicate that standard laboratory tests overestimate losses compared to those resulting from real environmental exposures

  14. Monitoring losses of copper based wood preservatives in the Thames estuary

    Energy Technology Data Exchange (ETDEWEB)

    Hingston, J.A. [Environmental Processes and Water Technology Research Group, Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College, London SW7 2AZ (United Kingdom)]. E-mail: james.hingston@psd.defra.gsi.gov.uk; Murphy, R.J. [Department of Biology, Imperial College, London SW7 2AZ (United Kingdom); Lester, J.N. [School of Water Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL (United Kingdom)

    2006-09-15

    Field trials were conducted at two sites in the Thames estuary to monitor losses of copper, chromium and arsenic from wood preservative treated timbers of varying sizes and treatment regimes. Results indicated that leaching tests conducted under standard laboratory conditions might overestimate losses compared to losses resulting from real environmental exposures. Amine copper treated wood was noted to leach higher levels of copper compared to chromated copper arsenate treated wood, and was therefore considered an inappropriate replacement biocide for fresh and marine construction purposes on this basis. Increases in copper concentrations in the outer sections of amine copper treated posts may have represented re-distribution of this component in this timber. No accumulation of metals was found in sediments surrounding field trial posts. - Wood preservative field trials in the UK indicate that standard laboratory tests overestimate losses compared to those resulting from real environmental exposures.

  15. ANUROS DEL GRADIENTE ALTITUDINAL DE LA ESTACIÓN EXPERIMETAL Y DEMOSTRATIVA EL RASGÓN (SANTANDER, COLOMBIA

    Directory of Open Access Journals (Sweden)

    SUÁREZ-BADILLO HENRY A.

    2004-12-01

    Full Text Available Se caracterizó la fauna de anuros sobre un gradiente altitudinal de 2200 a 3200 mabarcando tres formaciones vegetales, Selva Andina, Bosque Altoandino ySubpáramo, sobre la cordillera Oriental colombiana. Se realizaron 43 sesiones detrabajo entre Agosto de 2000 y Febrero de 2002 aplicando búsqueda libre porinspección visual y transectos. Se registraron doce de las especies conocidas de lazona y una más indescrita que constituye un nuevo registro y se suma a las dosespecies indescritas previamente registradas. Las abundancias absolutas fuerondiferentes entre las 3 formaciones vegetales y entre las épocas de muestreo.Contrariamente, no hubo diferencias entre el número de individuos obtenidos enlos meses secos contrastados con los meses lluviosos. La mayoría de especies eindividuos utilizaron el estrato herbáceo y parece no haber un uso diferencial delestrato vertical. E. prolixodiscus mostró preferencia por las bromelias como sustrato.Las curvas de acumulación de especies mostraron que el inventario está casicompleto en la Selva Andina y está en sus inicios en el Bosque Altoandino y elSubpáramo. Se observó una diversidad â baja entre los sitios evaluados.Eleutherodactylus anolirex, E. prolixodiscus y Eleutherodactylus sp. 1 sedistribuyen de forma continua en el gradiente, mientras que E. douglasi, E. lutitus,E. merostictus y Eleutherodactylus sp. 3 llegan hasta su parte media. E. douglasiy E. prolixodiscus aumentaron sus cotas altitudinales superiores (en 350 y 710 mrespectivamente. La disminución de la riqueza a lo largo del gradiente (quince,siete y tres especies es reflejo de una tendencia conocida, acentuada por elsubmuestreo de las partes media y alta de El Rasgón.

  16. The altitudinal temperature lapse rates applied to high elevation rockfalls studies in the Western European Alps

    Science.gov (United States)

    Nigrelli, Guido; Fratianni, Simona; Zampollo, Arianna; Turconi, Laura; Chiarle, Marta

    2018-02-01

    Temperature is one of the most important aspects of mountain climates. The relationships between air temperature and rockfalls at high-elevation sites are very important to know, but are also very difficult to study. In relation to this, a reliable method to estimate air temperatures at high-elevation sites is to apply the altitudinal temperature lapse rates (ATLR). The aims of this work are to quantify the values and the variability of the hourly ATLR and to apply this to estimated temperatures at high-elevation sites for rockfalls studies. To calculate ATLR prior the rockfalls, we used data acquired from two automatic weather stations that are located at an elevation above 2500 m. The sensors/instruments of these two stations are reliable because subjected to an accurate control and calibration once for year and the raw data have passed two automatic quality controls. Our study has yielded the following main results: (i) hourly ATLR increases slightly with increasing altitude, (ii) it is possible to estimate temperature at high-elevation sites with a good level of accuracy using ATLR, and (iii) temperature plays an important role on slope failures that occur at high-elevation sites and its importance is much more evident if the values oscillate around 0 °C with an amplitude of ±5 °C during the previous time-period. For these studies, it is not enough to improve the knowledge on air temperature, but it is necessary to develop an integrated knowledge of the thermal conditions of different materials involved in these processes (rock, debris, ice, water). Moreover, this integrated knowledge must be acquired by means of sensors and acquisition chains with known metrological traceability and uncertainty of measurements.

  17. Comparison of Risk Factor Profiles for Primary Open-Angle Glaucoma Subtypes Defined by Pattern of Visual Field Loss: A Prospective Study.

    Science.gov (United States)

    Kang, Jae H; Loomis, Stephanie J; Rosner, Bernard A; Wiggs, Janey L; Pasquale, Louis R

    2015-04-01

    We explored whether risk factor associations differed by primary open-angle glaucoma (POAG) subtypes defined by visual field (VF) loss pattern (i.e., paracentral or peripheral). We included 77,157 women in the Nurses' Health Study (NHS) and 42,773 men in the Health Professionals Follow-up Study (HPFS 1986-2010), and incident medical record confirmed cases of paracentral (n = 440) and peripheral (n = 865) POAG subtypes. We evaluated African heritage, glaucoma family history, body mass index (BMI), mean arterial blood pressure, diabetes mellitus, physical activity, smoking, caffeine intake, and alcohol intake. We used competing risk Cox regression analyses modeling age as the metameter and stratified by age, cohort, and event type. We sequentially identified factors with the least significant differences in associations with POAG subtypes ("stepwise down" approach with P for heterogeneity [P-het] 0.10) adverse associations with both POAG subtypes were observed with glaucoma family history, diabetes, African heritage, greater caffeine intake, and higher mean arterial pressure. These data indicate that POAG with early paracentral VF loss has distinct as well as common determinants compared with POAG with peripheral VF loss.

  18. Reducing the losses of optical metamaterials

    International Nuclear Information System (INIS)

    Fang, Anan

    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, (var e psilon). 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.

  19. 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.

  20. The mean energy loss by neutrino with magnetic moment in strong magnetic field with consideration of positronium contribution to photon dispersion

    Science.gov (United States)

    Mosichkin, A. F.

    2017-11-01

    The process of radiative decay of the neutrino with a magnetic moment in a strong magnetic field with consideration of positronium influence on photon dispersion has been studied. Positronium contribution to the photon polarization operator induces significant modifications of the photon dispersion law and neutrino radiative decay amplitude. It has been shown that the mean energy loss of a neutrino with magnetic a moment significantly increases, when the positronium contribution to photon dispersion is taken into account.

  1. AC Losses and Their Thermal Effect in High Temperature Superconducting Machines

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan

    2015-01-01

    In transient operations or fault conditions, high temperature superconducting (HTS) machines suffer AC losses which have an influence on the thermal stability of superconducting windings. In this paper, a method to calculate AC losses and their thermal effect in HTS machines is presented....... The method consists of three sub-models that are coupled only in one direction. The magnetic field distribution is first solved in a machine model, assuming a uniform current distribution in HTS windings. The magnetic fields on the boundaries are then used as inputs for an AC loss model which has...

  2. AC Losses and Their Thermal Effect in High-Temperature Superconducting Machines

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan

    2016-01-01

    In transient operations or fault conditions, hightemperature superconducting (HTS) machines suffer ac losses, which have an influence on the thermal stability of superconducting windings. In this paper, a method to calculate ac losses and their thermal effect in HTS machines is presented....... The method consists of three submodels that are coupled only in one direction. The magnetic field distribution is first solved in a machine model, assuming a uniform current distribution in HTS windings. The magnetic fields on the boundaries are then used as inputs for an ac loss model that has a homogeneous...

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

    International Nuclear Information System (INIS)

    Poehlsen, Thomas

    2013-07-01

    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 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 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 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 added to the

  4. Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

    Science.gov (United States)

    Frank, A.; Heller, R.; Goldacker, W.; Kling, A.; Schmidt, C.

    2008-02-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability.

  5. Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

    International Nuclear Information System (INIS)

    Frank, A; Heller, R; Goldacker, W; Kling, A; Schmidt, C

    2008-01-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability

  6. Microbending losses in multimode optical fibers

    International Nuclear Information System (INIS)

    Hussain, A.; Mudassar, A.A.; Hamza, M.Y.; Ikram, M.

    2003-01-01

    Microbending losses of optical fiber have been studied for different amplitude and shape of the deformer. Experimental results show that grooves of angel 60 degree cause more losses as compared to the grooves 90 degree. Intensity modulation induced by micro bends is considered as transudation mechanism for detecting environmental changes such as pressure, temperature, acceleration and magnetic and electric fields. An accelerometer has been designed on this principle and tested up to the acceleration of 65g. (author)

  7. Eddy current loss calculation and thermal analysis of axial-flux permanent magnet couplers

    Directory of Open Access Journals (Sweden)

    Di Zheng

    2017-02-01

    Full Text Available A three-dimensional magnetic field analytical model of axial-flux permanent magnet couplers is presented to calculate the eddy current loss, and the prediction of the copper plate temperature under various loads is analyzed. The magnetic field distribution is calculated, and then the eddy current loss is obtained, with the magnetic field analytical model established in cylindrical coordinate. The influence of various loads on eddy current loss is analyzed. Furthermore, a thermal model of axial-flux permanent magnet couplers is established by taking the eddy current loss as the heat source, using the electromagnetic-thermal coupled method. With the help of the thermal model, the influence of various loads on copper plate temperature rise is also analyzed. The calculated results are compared with the results of finite element method and measurement. The comparison results confirm the validity of the magnetic field analytical model and thermal model.

  8. [The 8-year follow-up study for clinical diagnostic potentials of frequency-doubling technology perimetry for perimetrically normal eyes of open-angle glaucoma patients with unilateral visual field loss].

    Science.gov (United States)

    Fan, X; Wu, L L; Xiao, G G; Ma, Z Z; Liu, F

    2018-03-11

    Objective: To analyze potentials of frequency-doubling technology perimetry (FDP) for diagnosing open-angle glaucoma (OAG) in perimetrically normal eyes of OAG patients diagnosed with standard automated perimetry (SAP) and relating factors from abnormalities on FDP to visual field loss on SAP. Methods: A prospective cohort study. Sixty-eight eyes of 68 OAG patients visiting the ophthalmic clinic of Peking University Third Hospital during November 2003 and October 2007 [32 primary open-angle glaucoma patients and 36 normal tension glaucoma patients, 32 males and 36 females, with an average age of (59±13) years] with unilateral field loss detected by SAP (Octopus101 tG2 program) were examined with the FDP N-30 threshold program (Humphrey Instruments) at baseline. Two groups, FDP positive group and FDP negative group, were divided based on the FDP results, and visual field examinations were followed by a series of SAP examinations for the perimetrically normal eyes over 8 years. During the follow-up, the difference of the converting rate of SAP tests between the two groups was analyzed. Differences between "convertors" and "non-convertors" of SAP tests in the FDP positive group, such as the cup-to-disk ratio and glaucomatous optic neuropathy rate, were also compared with the independent-sample t test or Wilcoxon two-sample test for continuous variable data and the χ(2) test or Fisher exact test for classified variable data and rates. Results: Forty-eight perimetrically normal eyes of 48 participants had complete data and a qualifying follow-up. Baseline FDP results were positive in 33 eyes and negative in 15 eyes. Of the eyes with positive FDP results, 22 eyes developed abnormal SAP results after 4.0 to 90.0 months (median 14.5 months) , whereas none of the eyes with negative FDP results developed abnormal SAP results. For perimetrically normal eyes in the FDP positive group, "converters" showed a greater cup-to-disk ratio (0.73±0.09 vs . 0.63±0.14, Wilcoxon two

  9. Electromagnetic therapeutic coils design to reduce energy loss

    Directory of Open Access Journals (Sweden)

    Syrek Przemyslaw

    2016-01-01

    Full Text Available The article introduces the problem of power loss reduction in applicators used in magnetotherapy. To generate magnetic field whose distribution is optimal and to reduce the power loss, the authors establish a set of parameters to evaluate the model of device. Results make it possible to infer that the real power input necessary to operate the magnetic field generator properly may vary significantly depending on construction and localization. The issues raised in this paper should be treated as a basis for further discussion on the construction of applicators used, e.g., in Transcranial Magnetic Stimulation.

  10. Nutrient losses from cattle co-digestate slurry during storage

    Directory of Open Access Journals (Sweden)

    Francesca Perazzolo

    2016-06-01

    Full Text Available Among environmental issues related to intensive livestock activity, emissions to air from manure management are of increasing concern. Thus the knowledge of the effect of treatment application on subsequent emissions from manure is required to assess the environment impact of management solutions. This work addresses the effect of anaerobic digestion and phase separation on emissions during storage by studying nitrogen losses from lab-scale stores and field pilot-scale stores of a co-digestate cattle slurry and its respective separated fractions. Lab-scale experiment was carried in temperature-controlled room where each fraction (untreated, separated liquid and separated solid was stored in duplicate for a period of 32 days in 30 L vessel. Pilot-scale experiment was carried out both during the cold season and during warm season for 90 days of storage. In both experimentations samples of the manure were analysed periodically for total Kjeldahl nitrogen (TKN, total ammonia nitrogen, dry matter and volatile solids and pH. These analyses allow estimating nitrogen losses in different storage conditions. Effects of mechanical separation and season were assessed by ANOVA (Wilcoxon test, P<0.05. In temperature controlled conditions nitrogen losses measured account for 13% and 26% of TKN for unseparated and separated slurries respectively. In field conditions during cold season nutrient losses were limited. On average unseparated and separated slurries lost respectively 6.8% and 12.6% of their initial TKN content. Much higher were the TKN losses from the slurries examined in warm season where losses raised up to 40% of the initial TKN content. Generally mechanical separation increases nutrient losses, but the differences were not significant in field conditions. The results highlighted that nutrient losses, in particular the nitrogen ones, can be considerable especially during summer storage. The latter, in case of separated slurries, are mainly related

  11. Study on ac losses of HTS coil carrying ac transport current

    International Nuclear Information System (INIS)

    Dai Taozhen; Tang Yuejin; Li Jingdong; Zhou Yusheng; Cheng Shijie; Pan Yuan

    2005-01-01

    Ac loss has an important influence on the thermal performances of HTS coil. It is necessary to quantify ac loss to ascertain its impact on coil stability and for sizing the coil refrigeration system. In this paper, we analyzed in detail the ac loss components, hysteresis loss, eddy loss and flux flow loss in the pancake HTS coil carrying ac transport current by finite element method. We also investigated the distribution of the ac losses in the coil to study the effects of magnetic field distribution on ac losses

  12. Measurement of mismatch loss in CPV modul

    Science.gov (United States)

    Liu, Mingguo; Kinsey, Geoffrey S.; Bagienski, Will; Nayak, Adi; Garboushian, Vahan

    2012-10-01

    A setup capable of simultaneously measuring I-V curves of a full string and its individual cells has been developed. This setup enables us to measure mismatch loss from individual cells in concert with various string combinations under varying field conditions. Mismatch loss from cells to plates at different off-track angles and mismatch from plates to strings in Amonix system during normal operation have been investigated.

  13. Alternating current loss characteristics in (bismuth,lead)SCCO and yttrium barium copper oxide superconducting tapes

    Science.gov (United States)

    Nguyen, Doan Ngoc

    Alternating current (AC) loss and current carrying capacity are two of the most crucial considerations in large-scale power applications of high temperature superconducting (HTS) conductors. AC losses result in an increased thermal load for cooling machines, and thus increased operating costs. Furthermore, AC losses can stimulate quenching phenomena or at least decrease the stability margin for superconducting devices. Thus, understanding AC losses is essential for the development of HTS AC applications. The main focus of this dissertation is to make reliable total AC loss measurements and interpret the experimental results in a theoretical framework. With a specially designed magnet, advanced total AC loss measurement system in liquid nitrogen (77 K) has been successfully built. Both calorimetric and electromagnetic methods were employed to confirm the validity of the measured results and to have a more thorough understanding of AC loss in HTS conductors. The measurement is capable of measuring total AC loss in HTS tapes over a wide range of frequency and amplitude of transport current and magnetic field. An accurate phase control technique allows measurement of total AC loss with any phase difference between the transport current and magnetic field by calorimetric method. In addition, a novel total AC loss measurement system with variable temperatures from 30 K to 100 K was successfully built and tested. Understanding the dependence of AC losses on temperature will enable optimization of the operating temperature and design of HTS devices. As a part of the dissertation, numerical calculations using Brandt's model were developed to study electrodynamics and total AC loss in HTS conductors. In the calculations, the superconducting electrical behavior is assumed to follow a power-law model. In general, the practical properties of conductors, including field-dependence of critical current density Jc, n-value and non-uniform distribution of Jc, can be accounted for in

  14. Loss Aversion under Prospect Theory: a Parameter-Free Measurement

    NARCIS (Netherlands)

    H. Bleichrodt (Han); M. Abdellaoui (Mohammed); C. Paraschiv (Corina)

    2007-01-01

    textabstractA growing body of qualitative evidence shows that loss aversion, a phenomenon formalized in prospect theory, can explain a variety of field and experimental data. Quantifications of loss aversion are, however, hindered by the absence of a general preference-based method to elicit the

  15. Radiative energy losses from a high-current air-blast arc

    International Nuclear Information System (INIS)

    Strachan, D.C.; Lidgate, D.; Jones, G.R.

    1977-01-01

    The importance of total radiation losses from high-current arcs burning in highly accelerated air flows representative of conditions existing in commercial gas-blast switchgear has been investigated. Such losses have been measured both in the high-pressure region upstream of a shaped orifice, where gas velocities are low, and in the region downstream where velocities become supersonic and pressure conditions approach ambient. The dominance of upstream electrode vapor as the source of plasma radiation losses is demonstrated and the importance of radiated losses within the arc energy balance is examined using measured values of axial electric field. For upstream electrodes of elkonite (sintered copper/tungsten) as used in high-power gas-blast circuit breakers, it is shown that some 30--40% of the electrical energy input upstream of the orifice is lost as radiation, while downstream this figure becomes 10--20%. The effect of reservoir pressure on arc electric fields is examined and the contribution to this effect of radiation losses is quantified

  16. Effect of ion orbit loss on the structure in the H-mode tokamak edge pedestal profiles of rotation velocity, radial electric field, density, and temperature

    International Nuclear Information System (INIS)

    Stacey, Weston M.

    2013-01-01

    An investigation of the effect of ion orbit loss of thermal ions and the compensating return ion current directly on the radial ion flux flowing in the plasma, and thereby indirectly on the toroidal and poloidal rotation velocity profiles, the radial electric field, density, and temperature profiles, and the interpretation of diffusive and non-diffusive transport coefficients in the plasma edge, is described. Illustrative calculations for a high-confinement H-mode DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] plasma are presented and compared with experimental results. Taking into account, ion orbit loss of thermal ions and the compensating return ion current is found to have a significant effect on the structure of the radial profiles of these quantities in the edge plasma, indicating the necessity of taking ion orbit loss effects into account in interpreting or predicting these quantities

  17. Station blackout: Deterministic and probabilistic approach in the field of electrical supply losses by EDF

    International Nuclear Information System (INIS)

    Meslin, T.; Carnino, A.

    1986-01-01

    This example shows the thoroughness of EDF's approach in processing the difficult problems of the loss of electrical power supplies. Efforts are continuing in several directions: continued revision and improvement of operating procedures in the event of loss of electrical power supplies, PWR plant operator training courses devoted to the problems of power supply losses, and continued testing on simulators, and particularly testing under real conditions, including tests lasting several hours made possible by the performance of the new EDF simulators (two-phase code and taking all power losses into account)

  18. Study on classical and excess eddy currents losses of Terfenol-D

    Energy Technology Data Exchange (ETDEWEB)

    Talebian, Soheil; Hojjat, Yousef [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ghodsi, Mojtaba [Department of Mechanical and Industrial Engineering, Sultan Qaboos University, Muscat (Oman); Karafi, Mohammad Reza [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2015-08-15

    In the present paper, classical and excess eddy currents losses of Terfenol-D are studied and effects of magnetic field frequency, peak of magnetic flux density and diameter of Terfenol-D on the eddy currents losses are investigated. To provide reliable data for the purpose of the paper, an experimental laboratory is fabricated and used to obtain major and minor hysteresis loops of Terfenol-D at different frequencies. In theoretical study, initially an analytical model based on uniform distribution of magnetic flux is developed which yields to calculation of classical eddy currents losses. Then, another eddy currents model based on non-uniform distribution of magnetic flux and nonlinear diffusion of electromagnetic fields is presented. The difference between output values of the two models is identified as excess eddy currents losses. Obtained results show that the values of excess losses are generally larger than classical losses and applying just classical model leads to wrong calculation of actual value of eddy currents losses. For the results obtained from two above models, empirical models with respect to the magnetic field frequency and the peak value of magnetic flux density are achieved which can predict the eddy currents losses precisely. To validate the empirical relations, experiments are repeated at a new frequency and values of power losses calculated from analytical equations are compared with the predicted values of the empirical models. The results point towards possibility to use the obtained empirical relations in order to calculate the classical and excess eddy currents losses of Terfenol-D at the frequencies below 200 Hz and different values of magnetic flux density. - Highlights: • Classical eddy currents loss of Terfenol-D is studied using Maxwell's laws. • Excess eddy currents loss of Terfenol-D is studied using Mayergoyz nonlinear model. • Effects of Terfenol-D geometry on the eddy currents losses are investigated. • Power

  19. Self-field AC losses and critical currents in multi-tube Ag-Bi-2223 conductors

    Energy Technology Data Exchange (ETDEWEB)

    Ciszek, M; Ashworth, S P; Campbell, A M [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); James, M P; Glowacki, B A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Garre, R; Conti, S [Centro Ricerche Europa Metalli, Fornaci di Barga, LU (Italy)

    1996-05-01

    The purpose of this work was to investigate the influence of different technological treatments of silver sheathed Bi-2223 tapes on the critical current density and the AC transport losses. The tapes were produced using the 'tube-in-tube' technique, by including a silver rod in the centre of the superconducting powder during packing of the silver tube. The aim of the process is to increase the silver to superconductor surface area and thus also the alignment at the centre of the conductor ceramic core. AC transport losses were measured by means of an electrical method using sinusoidally varying currents in the frequency range 30-180 Hz. In this range the power losses are hysteretic. The measured variation in losses from those predicted by a critical state model is attributed to the complex geometry of superconducting regions existing in these tapes. (author)

  20. Effects of electromagnetic fields on bone loss in hyperthyroidism rat model.

    Science.gov (United States)

    Liu, Chaoxu; Zhang, Yingchi; Fu, Tao; Liu, Yang; Wei, Sheng; Yang, Yong; Zhao, Dongming; Zhao, Wenchun; Song, Mingyu; Tang, Xiangyu; Wu, Hua

    2017-02-01

    Optimal therapeutics for hyperthyroidism-induced osteoporosis are still lacking. As a noninvasive treatment, electromagnetic fields (EMF) have been proven to be effective for treating osteoporosis in non-hyperthyroidism conditions. We herein systematically evaluated the reduced effects of EMF on osteoporosis in a hyperthyroidism rat model. With the use of Helmholtz coils and an EMF stimulator, 15 Hz/1 mT EMF was generated. Forty-eight 5-month-old male Sprague-Dawley rats were randomly divided into four different groups: control, levothyroxine treated (L-T4), EMF exposure + levothyroxine (EMF + L-T4), and EMF exposure without levothyroxine administration (EMF). All rats were treated with L-T4 (100 mg/day) except those in control and EMF groups. After 12 weeks, the results obtained from bone mineral density analyses and bone mechanical measurements showed significant differences between L-T4 and EMF + L-T4 groups. Micro CT and bone histomorphometric analyses indicated that trabecular bone mass and architecture in distal femur and proximal tibia were augmented and restored partially in EMF + L-T4 group. In addition, bone thyroid hormone receptors (THR) expression of hyperthyroidism rats was attenuated in EMF + L-T4 group, compared to control group, which was not observed in L-T4 group. According to these results, we concluded that 15 Hz/1 mT EMF significantly inhibited bone loss and micro architecture deterioration in hyperthyroidism rats, which might occur due to reduced THR expression caused by EMF exposure. Bioelectromagnetics. 38:137-150, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. 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

  2. Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau

    Science.gov (United States)

    Yang, Wei; Zheng, Yong; Gao, Cheng; Duan, Ji-Chuang; Wang, Shi-Ping; Guo, Liang-Dong

    2016-11-01

    Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow.

  3. New type low loss, strong field, RF coils for commercial nuclear fusion

    International Nuclear Information System (INIS)

    Ikegami, Shigetaka

    1990-01-01

    New RF coils of L-C-R connection loops type are proposed. One of the coils is only a bundle of μ order diameter isolated conductor, facing the both sides of the bundle ends each other for a capacity. The next characters were found by experiments. (1) This type coils show a sharp first resonance mode and few other modes are measured. (2) The complete proportional relation between the number of the conductors and the conductance of the bundle. (3) The ratio of the RF current resistance to the direct current resistance can be 1. Variational principle for eigenvalue problem was considered for it. The loss due to the vortex current in the conductor itself when exposed in the magnetic field was calculated accurately. And it was found that when the diameter of the conductor is 1/3 of the high frequency skin depth δ, the vortex current is very small. The litz wire can be used below 10 kHz. But this coil can be used above 100 MHz(δ≅7μ), because this coil need not to be stranded. For example, the turbulent heating at the axis of a tokamak plasma in μs order is possible, when a large amplitude stationary magnetosonic wave is excited by the magnetic piston of these coils array around the plasma. And the distance between the plasma and the coils can be large. The commercial nuclear fusion is thought to be possible. (author)

  4. Field-incidence noise transmission loss of general aviation aircraft double wall configurations

    Science.gov (United States)

    Grosveld, F. W.

    1984-01-01

    Theoretical formulations have been developed to describe the transmission of reverberant sound through an infinite, semi-infinite and a finite double panel structure. The model incorporates the fundamental resonance frequencies of each of the panels, the mass-air-mass resonances of the structure, the standing wave resonances in the cavity between the panels and finally the coincidence resonance regions, where the exciting sound pressure wave and flexural waves of each of the panels coincide. It is shown that phase cancellation effects of pressure waves reflected from the cavity boundaries back into the cavity allows the transmission loss of a finite double panel structure to be approximated by a finite double panel mounted in an infinite baffle having no cavity boundaries. Comparison of the theory with high quality transmission loss data yields good agreement in the mass-controlled frequency region. It is shown that the application of acoustic blankets to the double panel structure does not eliminate the mass-air-mass resonances if those occur at low frequencies. It is concluded that this frequency region of low noise transmission loss is a potential interior noise problem area for propeller driven aircraft having a double panel fuselage construction.

  5. Characteristic of Soil Nutrients Loss in Beiyunhe Reservoir Under the Simulated Rainfall

    Directory of Open Access Journals (Sweden)

    LIU Cao

    2016-05-01

    Full Text Available Field nutrient loss from soil became the major factor of the water pollution control in countryside in China. Beiyunhe reservoir is located in semiarid zone, where field nutrient loss distributed in summer. To assess the flied nutrient loss in Beiyunhe reservoir, we conducted experiments to study the characteristic of soil nutrients loss by analysis of the content of runoff water, soil nutrients and runoff water sediment under simulated rainfall. The results showed that the runoff happened in the rainstorm. In runoff water, the content of TN was 4.7~11.3 mg·L-1, ammonia nitrogen and nitrate nitrogen accounted for 44.51% of TN; the content of P was 0.66~1.35 mg·L-1, water soluble phosphorus accounted for 54.08% of TP. And the main loss of nutrients was in the surface soil, the loss of TN, NH4+-N, NO3--N, TP and DP were 29.79%, 52.09%, 10.21%, 16.48% and 5.27%, respectively. However, the most of field nutrient loss were in runoff sediment, the content of TN and TP were 0.66~1.27 mg·g-1 and 14.73~20 mg·g-1 in sediment, and TN and TP account for 82.28% and 99.89% of total loss of nutrient. After the rainstorm, the macro-aggregates were reduced 8.8%, and the micro-aggregates increased 9.5%.

  6. On relaxation mechanism of tangensial losses in soils

    International Nuclear Information System (INIS)

    Babayev, M.P.; Gerayzade, A.P.; Mamedov, N.A.

    2009-01-01

    By experimentally at high-frequency bridge method on dependence of a tangent of a corner of dielectric losses of soil fom humidity and frequency of an electromagnetic field are investigated. In air-dry samples of soils the size of the most probable time of a relaxation and its maximum is established. It is shown that in the field of gravitational humidity, in the soil sample, at a maximum of a tangent of a corner of dielectric losses through conductivity will be veiled, i.e. obviously is not shown. As a result of the received data it is established that in the field of the adsorbed soil moisture the spectrum of time of relaxation is characterized by the wide strip reflecting heterogeneity of its dielectric properties. All this is offered to be used at designing of delkometric hydrometers and measurement of soil humidity

  7. Low frequency AC losses in multi filamentary superconductors up to 15 Tesla

    International Nuclear Information System (INIS)

    Orlando, T.; Braun, C.; Foner, S.; Schwartz, B.; Zieba, A.

    1983-01-01

    Low frequency (1 Hz) ac losses were measured in a variety of A15 superconducting wires having different fiber geometries. Field modulations ofless than or equal to 1 tesla were superimposed on a fixed background field up to 15 tesla. Losses were measured for Nb 3 Sn in continuous fiber, modified jelly-roll, In Situ, and powder metallurgy processed materials, and for Nb 3 Al powder metallurgy processed materials. The results are compared with dc magnetization measurements. The losses are purely hysteretic at these low frequencies, scale with J /SUB c/ (above about 3 tesla), and are reduced substantially by twisting for all the materials. The lowest losses are observed for the Nb 3 Al wires

  8. Precipitation and air temperature control the variations of dissolved organic matter along an altitudinal forest gradient, Gongga Mountains, China.

    Science.gov (United States)

    Hu, Zhaoyong; Wang, Genxu; Sun, Xiangyang

    2017-04-01

    Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) contribute significantly to C and N cycling in forest ecosystems. Little information is available on the variations in the DOC and DON concentrations and depositions in bulk and stand precipitation within forests along an altitudinal gradient. To determine the temporal variations in the DOC and DON concentrations and depositions in different forests and the spatial variations along the elevation gradient, the DOC and DON concentrations and depositions were measured in bulk precipitation, throughfall, and stemflow within three forest types, i.e., broadleaf forest (BLF), broadleaf-coniferous forest (BCF), and coniferous forest (CF), during the wet season (May to October) on Gongga Mountain, China, in 2015. The concentrations of bulk precipitation in BLF, BCF, and CF were 3.92, 4.04, and 2.65 mg L -1 , respectively, for DOC and were 0.38, 0.26, and 0.29 mg L -1 , respectively, for DON. BCF had the highest DOC deposition both in bulk precipitation (45.12 kg ha -1 ) and stand precipitation (98.52 kg ha -1 ), whereas the highest DON deposition was in BLF (3.62 kg ha -1 bulk precipitation and 4.11 kg ha -1 stand precipitation) during the study period. The meteorological conditions of precipitation and air temperature significantly influenced the dissolved organic matter (DOM) depositions along the elevation gradient. The leaf area index did not show any correlation with DOM depositions during the growing season.

  9. 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.

  10. 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.

  11. The effects of degeneracy of the carrier ensemble on the energy loss rate and the high field mobility characteristics under the conditions of low lattice temperatures

    International Nuclear Information System (INIS)

    Basu, A.; Das, B.; Middya, T.R.; Bhattacharya, D.P.

    2017-01-01

    The rate of loss of energy of the non-equilibrium electrons to the acoustic mode lattice vibration in a degenerate semiconductor is obtained under the condition, when the lattice temperature is low enough, so that the traditional approximations like the elastic nature of the electron-phonon collisions and the truncation of the phonon distribution to the equipartition law are not valid any more. Using the results of the energy loss rate, the non-ohmic mobility is then calculated. Evaluating the loss rate and the non-ohmic mobility in degenerate samples of Si and Ge we find that significant changes in both the characteristics have been effected compared to that in the non-degenerate samples, in the regime of lower energy and for relatively lower fields. The effected changes are more significant the lower the lattice temperature is.

  12. Growth and physiological responses to drought and elevated ultraviolet-B in two contrasting populations of Hippophae rhamnoides

    Energy Technology Data Exchange (ETDEWEB)

    Yongqing Yang; Yinan Yao; Gang Xu [Chinese Academy of Sciences, Chengdu Inst. of Biology, Chengdu (China); Chunyang Li [Graduate School of the Chinese Academy of Sciences, Beijing (China)

    2005-08-01

    In the southeast of the Qinghai-Tibetan Plateau of China, sea buckthorn (Hippophae rhamnoides L.), which is a thorny nitrogen-fixing deciduously perennial shrub, has been widely used in forest restoration as the pioneer species. In our study, two contrasting populations from the low and high altitudinal regions were employed to investigate the effects of drought, ultraviolet-B (UV-B) and their combination on sea buckthorn. The experimental design included two watering regimes (well watered and drought stressed) and two levels of UV-B (with and without UV-B supplementation). Drought significantly decreased total biomass, total leaf area and specific leaf area (SLA), and increased root/shoot ratio, fine root/coarse root ratio and abscisic acid content (ABA) in both populations. However, the high altitudinal population was more responsive to drought than the low altitudinal population. On the other hand, elevated UV-B induced increase in anthocyanins in both populations, whereas he accumulation of UV-absorbing compounds occurred only in the low altitudinal population. The drought-induced enhancement of ABA in the high altitudinal population was significantly suppressed in the combination of drought and elevated UV-B. Moreover, significant drought x UV-B interaction was detected on total biomass in both populations, total leaf area and fine root/coarse root in the low altitudinal population, and SLA in the high altitudinal population. These results demonstrated that there were different adaptive responses between two contrasting populations, the high altitudinal population exhibited higher tolerance to drought and UV-B than the low altitudinal population. (au)

  13. Use of Annual Phosphorus Loss Estimator (APLE) Model to Evaluate a Phosphorus Index.

    Science.gov (United States)

    Fiorellino, Nicole M; McGrath, Joshua M; Vadas, Peter A; Bolster, Carl H; Coale, Frank J

    2017-11-01

    The Phosphorus (P) Index was developed to provide a relative ranking of agricultural fields according to their potential for P loss to surface water. Recent efforts have focused on updating and evaluating P Indices against measured or modeled P loss data to ensure agreement in magnitude and direction. Following a recently published method, we modified the Maryland P Site Index (MD-PSI) from a multiplicative to a component index structure and evaluated the MD-PSI outputs against P loss data estimated by the Annual P Loss Estimator (APLE) model, a validated, field-scale, annual P loss model. We created a theoretical dataset of fields to represent Maryland conditions and scenarios and created an empirical dataset of soil samples and management characteristics from across the state. Through the evaluation process, we modified a number of variables within the MD-PSI and calculated weighting coefficients for each P loss component. We have demonstrated that our methods can be used to modify a P Index and increase correlation between P Index output and modeled P loss data. The methods presented here can be easily applied in other states where there is motivation to update an existing P Index. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. Food losses and waste in the French oilcrops sector

    OpenAIRE

    Fine Frédéric; Lucas Jean-Louis; Chardigny Jean-Michel; Redlingshöfer Barbara; Renard Michel

    2015-01-01

    INRA has initiated a comprehensive approach to food loss and waste for all the plant and animal sectors, from field to distribution. In this study, all comestibles that leave the human food chain and are not recycled into animal feed are considered as losses and waste. The main French oilseed sectors are studied (rapeseed, sunflower and soya, as well as tofu). In order to identify the key sources of loss, all of the various steps in the ...

  15. Altitudinal distribution and advertisement call of Colostethus latinasus (Amphibia: Dendrobatidae), endemic species from eastern Panama and type species of Colostethus , with a molecular assessment of similar sympatric species.

    Science.gov (United States)

    Ibáñez, Roberto D; Griffith, Edgardo J; Lips, Karen R; Crawford, Andrew J

    2017-04-12

    We conducted a molecular assessment of Colostethus-like frogs along an elevational gradient in the Serranía de Pirre, above Santa Cruz de Cana, eastern Panama, aiming to establish their species identity and to determine the altitudinal distribution of C. latinasus. Our findings confirm the view of C. latinasus as an endemic species restricted to the highlands of this mountain range, i.e., 1350-1475 m.a.s.l., considered to be type locality of this species. We described the advertisement call of C. latinasus that consists of a series of 4-18 single, short and relatively loud "peep"-like notes given in rapid succession, and its spectral and temporal features were compared with calls of congeneric species. For the first time, DNA sequences from C. latinasus were obtained, since previously reported sequences were based on misidentified specimens. This is particularly important because C. latinasus is the type species of Colostethus, a genus considered paraphyletic according to recent phylogenetic analyses based on molecular data.

  16. Marsh dieback, loss, and recovery mapped with satellite optical, airborne polarimetric radar, and field data

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina; Chi, Zhaohui; Jones, Cathleen E.; Bannister, Terri

    2014-01-01

    Landsat Thematic Mapper and Satellite Pour l'Observation de la Terre (SPOT) satellite based optical sensors, NASA Uninhabited Aerial Vehicle synthetic aperture radar (UAVSAR) polarimetric SAR (PolSAR), and field data captured the occurrence and the recovery of an undetected dieback that occurred between the summers of 2010, 2011, and 2012 in the Spartina alterniflora marshes of coastal Louisiana. Field measurements recorded the dramatic biomass decrease from 2010 to 2011 and a biomass recovery in 2012 dominated by a decrease of live biomass, and the loss of marsh as part of the dieback event. Based on an established relationship, the near-infrared/red vegetation index (VI) and site-specific measurements delineated a contiguous expanse of marsh dieback encompassing 6649.9 ha of 18,292.3 ha of S. alterniflora marshes within the study region. PolSAR data were transformed to variables used in biophysical mapping, and of this variable suite, the cross-polarization HV (horizontal send and vertical receive) backscatter was the best single indicator of marsh dieback and recovery. HV backscatter exhibited substantial and significant changes over the dieback and recovery period, tracked measured biomass changes, and significantly correlated with the live/dead biomass ratio. Within the context of regional trends, both HV and VI indicators started higher in pre-dieback marshes and exhibited substantially and statistically higher variability from year to year than that exhibited in the non-dieback marshes. That distinct difference allowed the capturing of the S. alterniflora marsh dieback and recovery; however, these changes were incorporated in a regional trend exhibiting similar but more subtle biomass composition changes.

  17. Visual attention measures predict pedestrian detection in central field loss: a pilot study.

    Directory of Open Access Journals (Sweden)

    Concetta F Alberti

    Full Text Available The ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT and static attention (Useful Field of View; UFOV were predictive of the ability of people with central field loss (CFL to detect pedestrian hazards in simulated driving.11 people with bilateral CFL (visual acuity 20/30-20/200 and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests. Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision.UFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse (84% and 97%, respectively; p = 0.001. For CFL participants, higher proportions of timely reactions correlated significantly with higher (better MOT speed thresholds (r = 0.73, p = 0.01, with better performance on the UFOV divided and selective attention subtests (r = -0.66 and -0.62, respectively, p<0.04, with better contrast sensitivity scores (r = 0.54, p = 0.08 and smaller scotomas (r = -0.60, p = 0.05.Our results suggest that brief laboratory-based tests of visual attention may provide useful measures of functional visual ability of individuals with CFL relevant to more complex mobility tasks.

  18. Nanoparticle electrostatic loss within corona needle charger during particle-charging process

    International Nuclear Information System (INIS)

    Huang Chenghsiung; Alonso, Manuel

    2011-01-01

    A numerical investigation has been carried out to examine the electrostatic loss of nanoparticles in a corona needle charger. Two-dimensional flow field, electric field, particle charge, and particle trajectory were simulated to obtain the electrostatic deposition loss at different conditions. Simulation of particle trajectories shows that the number of charges per particle during the charging process depends on the particle diameter, radial position from the symmetry axis, applied voltage, Reynolds number, and axial distance along the charger. The numerical results of nanoparticle electrostatic loss agreed fairly well with available experimental data. The results reveal that the electrostatic loss of nanoparticles increases with increasing applied voltage and electrical mobility of particles; and with decreasing particle diameter and Reynolds number. A regression equation closely fitted the obtained numerical results for different conditions. The equation is useful for directly calculating the electrostatic loss of nanoparticles in the corona needle charger during particle-charging process.

  19. 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

  20. Low-loss metamaterial electromagnetically induced transparency based on electric toroidal dipolar response

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hai-ming; Liu, Shao-bin, E-mail: lsb@nuaa.edu.cn; Liu, Si-yuan; Ding, Guo-wen; Yang, Hua; Yu, Zhi-yang; Zhang, Hai-feng [Key Laboratory of Radar Imaging and Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 (China); Wang, Shen-yun [Research Center of Applied Electromagnetic, Nanjing University of Information Science and Technology, Nanjing, 210044 (China)

    2015-02-23

    In this paper, a low-loss and high transmission analogy of electromagnetically induced transparency based on electric toroidal dipolar response is numerically and experimentally demonstrated. It is obtained by the excitation of the low-loss electric toroidal dipolar response, which confines the magnetic field inside a dielectric substrate with toroidal geometry. The metamaterial electromagnetically induced transparency (EIT) structure is composed of the cut wire and asymmetric split-ring resonators. The transmission level is as high as 0.88, and the radiation loss is greatly suppressed, which can be proved by the surface currents distributions, the magnetic field distributions, and the imaginary parts of the effective permeability and permittivity. It offers an effective way to produce low-loss and high transmission metamaterial EIT.

  1. Soil Loss Vulnerability in an Agricultural Catchment in the Atlantic Forest Biome in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Rafael Gotardo

    2016-11-01

    Full Text Available This study estimates soil loss vulnerability using field samples and spatial data in a 30 km² area in the Atlantic forest biome in southern Brazil. The anthropogenic part of the landscape consists mainly of small agricultural properties. Soil loss vulnerability was calculated using adaptations of the universal soil loss equation. The results were compared to sediment data collected during field surveys. Spatial analysis was performed using a geographical information system (GIS and fine resolution data (1 m. Both field and spatial analyses produced similar results, 5.390 tons of soil loss per year using field data and 5.691 tons per year using GIS. Using soil loss and sediment data related to the Concordia River, we estimate that of all the exported sediment 25% of the lost soil reaches the river. These data are an effective source of information for municipal administrators of the region, which consists of small agricultural catchments (dominated by small properties that comprise the regional economy. A thematic map was used to determine sub-drainage priority as information for public managers.

  2. The groningen longitudinal glaucoma study III. The predictive value of frequency-doubling perimetry and GDx nerve fibre analyser test results for the development of glaucomatous visual field loss

    NARCIS (Netherlands)

    Heeg, G. P.; Jansonius, N. M.

    Purpose To investigate whether frequency-doubling perimetry (FDT) and nerve fibre analyser (GDx) test results are able to predict glaucomatous visual field loss in glaucoma suspect patients. Methods A large cohort of glaucoma suspect patients (patients with ocular hypertension or a positive family

  3. Barbel species arrangement in a regional Natura 2000 network (Emilia Romagna, Northern Italy: An altitudinal perspective

    Directory of Open Access Journals (Sweden)

    Federica Piccoli

    2017-07-01

    Full Text Available Southern Europe hosts a large number of critical catchments for freshwater biodiversity, including endemic fish species. Unfortunately, these areas are severely threatened due to direct and indirect anthropogenic effects. In this context, with the aim to improve the effectiveness of threatened fish protection, the Life project BARBIE (LIFE13 NAT/IT/001129 started in 2014 and focused on three congeneric species of the genus Barbus: two of “priority interest” sensu Habitats Directive [Barbus caninus (Bonaparte, 1839, and B. plebejus (Bonaparte, 1839], and one alien [Barbus barbus (Linnaeus, 1758]. Our main objective was to assess the contribution of a complex of protected areas included in the Natura 2000 network – located in the provinces of Parma, Piacenza and Reggio Emilia (Norther Italy – to support the presence of the three barbel species in analysis. Additionally, we explored the role of a set of environmental variables (i.e., physical, chemical, biological, and land-use descriptors to drive the current conditions of the study sites and the responses of Barbus species. As a general rule, the present study confirmed a clear decline of the local native barbel populations, and confirmed the existence of a zonation pattern of the barbel taxa. Hence, we observed a strong altitude segregation between native vs. alien species, with the exotic B. barbus currently limited to plain and only sporadically present in the Apennine areas as genetic introgression. These evidences mirrored the altitudinal gradients of anthropogenic disturbance. The main causes were the progressive disappearance of well-structured riparian stripes, and the intense land use change, ranging from semi-natural patches (mountain and hill sectors to land clearing for intensive agriculture (lowland sectors. This highlights the need to take into account the spatial dynamics of alien invasive species in programming recovery actions that could have unexpected impacts to the

  4. 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%. © 2016 John Wiley & Sons Ltd.

  5. 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.

  6. AC losses in high Tc superconductors

    International Nuclear Information System (INIS)

    Campbell, A.M.

    1998-01-01

    Full text: Although in principle the AC losses in high Tc superconductors can be calculated from the critical current density, a number of complications make this difficult. The Jc is very field dependent, there are intergranular and intragranular critical currents, the material is anisotropic and there is usually a large demagnetising factor. Care must be taken in interpreting electrical measurements since the voltage depends on the position of the contacts. In spite of these complications the simple theory of Norris has proved surprisingly successful and arguments will be presented as to why this is the case. Results on a range of tapes will be compared with theory and numerical methods for predicting losses discussed. Finally a theory for coupling losses will be given for a composite conductor with high resistance barriers round the filaments

  7. Limitations on plasma acceleration due to synchrotron losses

    International Nuclear Information System (INIS)

    Barletta, W.A.; Lee, E.P.; Bonifacio, R.; De Salvo, L.

    1999-01-01

    In this letter we consider the effect of synchrotron radiation losses due to the betatron motion of the electron beam in its self-induced magnetic field in a plasma accelerator taking into account the charge neutralization factor. The most favorable case is where the plasma density is smaller than the beam density. The contrary regime is strongly disfavored by the synchrotron radiation loss for beams with characteristics for TeV energies. In both cases we find that upon increasing the plasma density the synchrotron losses kill the acceleration process, so that there are limitations on the maximum allowable plasma density

  8. 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

  9. Audiological results with Baha in conductive and mixed hearing loss.

    Science.gov (United States)

    Pfiffner, Flurin; Caversaccio, Marco-Domenico; Kompis, Martin

    2011-01-01

    The level of improvement in the audiological results of Baha(®) users mainly depends on the patient's preoperative hearing thresholds and the type of Baha sound processor used. This investigation shows correlations between the preoperative hearing threshold and postoperative aided thresholds and audiological results in speech understanding in quiet of 84 Baha users with unilateral conductive hearing loss, bilateral conductive hearing loss and bilateral mixed hearing loss. Secondly, speech understanding in noise of 26 Baha users with different Baha sound processors (Compact, Divino, and BP100) is investigated. Linear regression between aided sound field thresholds and bone conduction (BC) thresholds of the better ear shows highest correlation coefficients and the steepest slope. Differences between better BC thresholds and aided sound field thresholds are smallest for mid-frequencies (1 and 2 kHz) and become larger at 0.5 and 4 kHz. For Baha users, the gain in speech recognition in quiet can be expected to lie in the order of magnitude of the gain in their hearing threshold. Compared to its predecessor sound processors Baha(®) Compact and Baha(®) Divino, Baha(®) BP100 improves speech understanding in noise significantly by +0.9 to +4.6 dB signal-to-noise ratio, depending on the setting and the use of directional microphone. For Baha users with unilateral and bilateral conductive hearing loss and bilateral mixed hearing loss, audiological results in aided sound field thresholds can be estimated with the better BC hearing threshold. The benefit in speech understanding in quiet can be expected to be similar to the gain in their sound field hearing threshold. The most recent technology of Baha sound processor improves speech understanding in noise by an order of magnitude that is well perceived by users and which can be very useful in everyday life. Copyright © 2011 S. Karger AG, Basel.

  10. Agroecology and biodiversity of the catchment area of Swat River

    International Nuclear Information System (INIS)

    Ahmad, H.; Ahmed, R.

    2003-01-01

    Agroecological studies of the of the Swat River catchment area showed that the terrestrial ecosystem of the area is divided into subtropical, humid temperate, cool temperate, cold temperate, subalpine, alpine and cold desert zones. Indicator species along with their altitudinal limits are specified for each zone. Unplanned population growth, agriculture extension, habitat losses, deforestation, environmental pollution and unwise use of natural resources are threats to the natural biodiversity of these zones. Its severity is very evident in the subtropical and humid temperate zones. The losses encountered to the biodiversity of the area under the influence of various anthropogenic stresses are highlighted. (author)

  11. Modeling Phosphorus Losses through Surface Runoff and Subsurface Drainage Using ICECREAM.

    Science.gov (United States)

    Qi, Hongkai; Qi, Zhiming; Zhang, T Q; Tan, C S; Sadhukhan, Debasis

    2018-03-01

    Modeling soil phosphorus (P) losses by surface and subsurface flow pathways is essential in developing successful strategies for P pollution control. We used the ICECREAM model to simultaneously simulate P losses in surface and subsurface flow, as well as to assess effectiveness of field practices in reducing P losses. Monitoring data from a mineral-P-fertilized clay loam field in southwestern Ontario, Canada, were used for calibration and validation. After careful adjustment of model parameters, ICECREAM was shown to satisfactorily simulate all major processes of surface and subsurface P losses. When the calibrated model was used to assess tillage and fertilizer management scenarios, results point to a 10% reduction in total P losses by shifting autumn tillage to spring, and a 25.4% reduction in total P losses by injecting fertilizer rather than broadcasting. Although the ICECREAM model was effective in simulating surface and subsurface P losses when thoroughly calibrated, further testing is needed to confirm these results with manure P application. As illustrated here, successful use of simulation models requires careful verification of model routines and comprehensive calibration to ensure that site-specific processes are accurately represented. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  12. AC Loss Analysis of MgB2-Based Fully Superconducting Machines

    Science.gov (United States)

    Feddersen, M.; Haran, K. S.; Berg, F.

    2017-12-01

    Superconducting electric machines have shown potential for significant increase in power density, making them attractive for size and weight sensitive applications such as offshore wind generation, marine propulsion, and hybrid-electric aircraft propulsion. Superconductors exhibit no loss under dc conditions, though ac current and field produce considerable losses due to hysteresis, eddy currents, and coupling mechanisms. For this reason, many present machines are designed to be partially superconducting, meaning that the dc field components are superconducting while the ac armature coils are conventional conductors. Fully superconducting designs can provide increases in power density with significantly higher armature current; however, a good estimate of ac losses is required to determine the feasibility under the machines intended operating conditions. This paper aims to characterize the expected losses in a fully superconducting machine targeted towards aircraft, based on an actively-shielded, partially superconducting machine from prior work. Various factors are examined such as magnet strength, operating frequency, and machine load to produce a model for the loss in the superconducting components of the machine. This model is then used to optimize the design of the machine for minimal ac loss while maximizing power density. Important observations from the study are discussed.

  13. Temperature dependence of the minimum in AC power losses of (Nb/sub 0.99/Zr/sub 0.01/)3Sn in parallel AC and DC magnetic fields

    International Nuclear Information System (INIS)

    Kovachev, V.T.

    1980-01-01

    ac losses P/sub L/ of bronze-processed (Nb/sub 0.99/Zr/sub 0.01/) 3 Sn strips have been measured between 4.2 and 16.5 K in the presence of a dc magnetic field H 0 . The measurements were performed using an electronic wattmeter with both ac and dc fields parallel to the long flat surfaces of the sample. A minimum in the function P/sub L/(H 0 ) was observed for fixed ac amplitudes h 0 . This minimum was found to occur in the entire temperature range between 4.2 and 16.5 K. A similar minimum was recently reported in Nb 3 Ge [Thompson et al., J. Appl. Phys. 50, 3514 (1979)] at 4.2 K. The position of the minimum is explained here by the same physical model as in Thompson et al. [J. Appl. Phys. 50, 3514 (1979)]; and Clem (ibid. 3518), but extending the model to include the temperature dependence of the entry surface shielding fields ΔH/sub en/(B,T) for flux density in the sample B=0. It is also shown here that loss minimum measurements can be used for the determination of ΔH/sub en/(0,T) in the temperature range 4.2--16.5 K

  14. Nonmonotonic low frequency losses in HTSCs

    International Nuclear Information System (INIS)

    Castro, H; Gerber, A; Milner, A

    2007-01-01

    A calorimetric technique has been used in order to study ac-field dissipation in ceramic BSCCO samples at low frequencies between 0.05 and 250 Hz, at temperatures from 65 to 90 K. In contrast to previous studies, where ac losses have been reported with a linear dependence on magnetic field frequency, we find a nonmonotonic function presenting various maxima. Frequencies corresponding to local maxima of dissipation depend on the temperature and the amplitude of the ac magnetic field. Flux creep is argued to be responsible for this behaviour. A simple model connecting the characteristic vortex relaxation times (flux creep) and the location of dissipation maxima versus frequency is proposed

  15. Reducing Runoff Loss of Applied Nutrients in Oil Palm Cultivation Using Controlled-Release Fertilizers

    Directory of Open Access Journals (Sweden)

    A. Bah

    2014-01-01

    Full Text Available Controlled-release fertilizers are expected to minimize nutrient loss from crop fields due to their potential to supply plant-available nutrients in synchrony with crop requirements. The evaluation of the efficiency of these fertilizers in tropical oil palm agroecological conditions is not yet fully explored. In this study, a one-year field trial was conducted to determine the impact of fertilization with water soluble conventional mixture and controlled-release fertilizers on runoff loss of nutrients from an immature oil palm field. Soil and nutrient loss were monitored for one year in 2012/2013 under erosion plots of 16 m2 on 10% slope gradient. Mean sediments concentration in runoff amounted to about 6.41 t ha−1. Conventional mixture fertilizer posed the greatest risk of nutrient loss in runoff following fertilization due to elevated nitrogen (6.97%, potassium (13.37%, and magnesium (14.76% as percentage of applied nutrients. In contrast, this risk decreased with the application of controlled-release fertilizers, representing 0.75–2.44% N, 3.55–5.09% K, and 4.35–5.43% Mg loss. Meanwhile, nutrient loss via eroded sediments was minimal compared with loss through runoff. This research demonstrates that the addition of controlled-release fertilizers reduced the runoff risks of nutrient loss possibly due to their slow-release properties.

  16. Joule loss on a Faraday shield of JT-60 ICRF test antenna

    International Nuclear Information System (INIS)

    Fujii, Tsuneyuki; Saigusa, Mikio; Ikeda, Yoshitaka; Kimura, Haruyuki; Hirashima, Teruhisa; Uehara, Munenori.

    1988-01-01

    Joule loss on a Faraday shield of JT-60 ICRF test antenna with a conductive casing is investigated at the frequency range of 120 MHz. The magnetic field radiated from the antenna is measured by three-dimensionally scanning an rf probe both inside and outside the antenna casing. The magnetic field perpendicular to the Faraday shield, B x , is found to be the largest component near the Faraday shield. It consequently gives the major part of the joule loss on the Faraday shield. The temperature distribution of the Faraday shield due to joule loss is measured directly with a thermocamera. It is confirmed that the area of the high temperature rise is consistent with the peak positions of the B x field. Faraday shield resistance which is estimated from power measurements agrees with the theoretical value. (author)

  17. Parameter uncertainty analysis for the annual phosphorus loss estimator (APLE) model

    Science.gov (United States)

    Technical abstract: 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 conduct an uncertainty analys...

  18. Using a phosphorus loss model to evaluate and improve phosphorus indices.

    Science.gov (United States)

    Bolster, Carl H; Vadas, Peter A; Sharpley, Andrew N; Lory, John A

    2012-01-01

    In most states, the phosphorus (P) index (PI) is the adopted strategy for assessing a field's vulnerability to P loss; however, many state PIs have not been rigorously evaluated against measured P loss data to determine how well the PI assigns P loss risk-a major reason being the lack of field data available for such an analysis. Given the lack of P loss data available for PI evaluation, our goal was to demonstrate how a P loss model can be used to evaluate and revise a PI using the Pennsylvania (PA) PI as an example. Our first objective was to compare two different formulations-multiplicative and component-for calculating a PI. Our second objective was to evaluate whether output from a P loss model can be used to improve PI weighting by calculating weights for modified versions of the PA PI from model-generated P loss data. Our results indicate that several potential limitations exist with the original multiplicative index formulation and that a component formulation is more consistent with how P loss is calculated with P loss models and generally provides more accurate estimates of P loss. Moreover, using the PI weights calculated from the model-generated data noticeably improved the correlation between PI values and a large and diverse measured P loss data set. The approach we use here can be used with any P loss model and PI and thus can serve as a guide to assist states in evaluating and modifying their PI. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  19. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C

    Directory of Open Access Journals (Sweden)

    Zixun Chen

    2017-07-01

    Full Text Available Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.

  20. Assessing color vision loss among solvent-exposed workers.

    Science.gov (United States)

    Mergler, D; Blain, L

    1987-01-01

    Acquired color vision loss has been associated with exposure to organic solvents in the workplace. However, not all tests of chromatic discrimination loss are designed to detect acquired, as opposed to congenital, loss. The Lanthony D-15 desaturated panel (D-15-d), a simple 15 cap color arrangement test, designed to identify mild acquired dyschromatopsia, can be administered rapidly in the field, under standard conditions. The objective of the present study was to evaluate the D-15-d among 23 solvent-exposed workers of a paint manufacturing plant, by comparing the results obtained with the D-15-d to those obtained with the Farnsworth-Munsell 100 Hue (FM-100), a highly sensitive measure of color vision loss. The D-15-d revealed a significantly higher prevalence of dyschromatopsia among the ten highly exposed workers (80%) as compared to the 13 moderately exposed workers (30.8%); FM-100 results revealed one false positive. All dyschromatopic workers presented blue-yellow loss; the FM-100 detected eight complex patterns, while the D-15-d identified 5. Comparison of D-15-d and FM-100 scores were highly correlated (corr. coeff. 0.87; p less than 0.001). Multiple regression analyses showed both scores to be significantly related to age and exposure level. The findings of this study indicate that the D-15-d is an adequate instrument for field study batteries. However, the FM-100 should be used for more detailed assessment.

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

    International Nuclear Information System (INIS)

    Takeuchi, Nozomu

    2013-01-01

    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. (letter)

  2. Altitudinal variations of ground tissue and xylem tissue in terminal shoot of woody species: implications for treeline formation.

    Science.gov (United States)

    Chen, Hong; Wang, Haiyang; Liu, Yanfang; Dong, Li

    2013-01-01

    1. The terminal shoot (or current-year shoot), as one of the most active parts on a woody plant, is a basic unit determining plant height and is potentially influenced by a variety of environmental factors. It has been predicted that tissues amount and their allocation in plant stems may play a critical role in determining plant size in alpine regions. The primary structure in terminal shoots is a key to our understanding treeline formation. The existing theories on treeline formation, however, are still largely lacking of evidence at the species level, much less from anatomy for the terminal shoot. 2. The primary structures within terminal shoot were measured quantitatively for 100 species from four elevation zones along the eastern slope of Gongga Mountain, southwestern China; one group was sampled from above the treeline. An allometric approach was employed to examine scaling relationships interspecifically, and a principal components analysis (PCA) was performed to test the relation among primary xylem, ground tissue, species growth form and altitude. 3. The results showed that xylem tissue size was closely correlated with ground tissue size isometrically across species, while undergoing significant y- or/and x-intercept shift in response to altitudinal belts. Further, a conspicuous characteristic of terminal shoot was its allocation of contrasting tissues between primary xylem and ground tissues with increasing elevation. The result of the PCA showed correlations between anatomical variation, species growth form/height classes and environment. 4. The current study presents a comparative assessment of the allocation of tissue in terminal shoot across phylogenically and ecologically diverse species, and analyzes tissue, function and climate associations with plant growth forms and height classes among species. The interspecific connection between primary xylem ratio and plant size along an elevation gradient suggests the importance of primary xylem in explaining

  3. Altitudinal variations of ground tissue and xylem tissue in terminal shoot of woody species: implications for treeline formation.

    Directory of Open Access Journals (Sweden)

    Hong Chen

    Full Text Available 1. The terminal shoot (or current-year shoot, as one of the most active parts on a woody plant, is a basic unit determining plant height and is potentially influenced by a variety of environmental factors. It has been predicted that tissues amount and their allocation in plant stems may play a critical role in determining plant size in alpine regions. The primary structure in terminal shoots is a key to our understanding treeline formation. The existing theories on treeline formation, however, are still largely lacking of evidence at the species level, much less from anatomy for the terminal shoot. 2. The primary structures within terminal shoot were measured quantitatively for 100 species from four elevation zones along the eastern slope of Gongga Mountain, southwestern China; one group was sampled from above the treeline. An allometric approach was employed to examine scaling relationships interspecifically, and a principal components analysis (PCA was performed to test the relation among primary xylem, ground tissue, species growth form and altitude. 3. The results showed that xylem tissue size was closely correlated with ground tissue size isometrically across species, while undergoing significant y- or/and x-intercept shift in response to altitudinal belts. Further, a conspicuous characteristic of terminal shoot was its allocation of contrasting tissues between primary xylem and ground tissues with increasing elevation. The result of the PCA showed correlations between anatomical variation, species growth form/height classes and environment. 4. The current study presents a comparative assessment of the allocation of tissue in terminal shoot across phylogenically and ecologically diverse species, and analyzes tissue, function and climate associations with plant growth forms and height classes among species. The interspecific connection between primary xylem ratio and plant size along an elevation gradient suggests the importance of primary

  4. Altitudinal gradients, midwinter melt, and wind effects on snow accumulation in semiarid midlatitude Andes under La Niña conditions

    Science.gov (United States)

    Ayala, A.; McPhee, J.; Vargas, X.

    2014-04-01

    The Andes Cordillera remains a sparsely monitored and studied snow hydrology environment in comparison to similar mountain ranges in the Northern Hemisphere. In order to uncover some of the key processes driving snow water equivalent (SWE) spatial variability, we present and analyze a distributed SWE data set, sampled at the end of accumulation season 2011. Three representative catchments across the region were monitored, obtaining measurements in an elevation range spanning 2000 to 3900 m asl and from 32.4° to 34.0°S in latitude. Climatic conditions during this season corresponded to a moderate La Niña phenomenon, which is generally correlated with lower-than normal accumulation. Collected measurements can be described at the regional and watershed extents by altitudinal gradients that imply an increase by a factor of two in snow depth between 2200 and 3000 m asl, though with significant variability at the upper sites. In these upper sites, we found north-facing, wind-sheltered slopes showing 25% less average SWE values than south-facing, wind-exposed ones. This suggests that under these conditions, solar radiation dominated wind transport effects in controlling end-of-winter variability. Nevertheless, we found clusters of snow depth measurements above 3000 m asl that can be explained by wind exposure differences. This is the first documented snow depth data set of this spatial extent for this region, and it is framed within an ongoing research effort aimed at improving understanding and modeling of snow hydrology in the extratropical Andes Cordillera.

  5. Experimental investigation of energy loss and end loss physics in a linear theta pinch. Scientific report 81-3

    International Nuclear Information System (INIS)

    Jacoby, B.A.

    1981-01-01

    The results of an experimental study of particle and thermal loss processes from a 50-cm long theta pinch are presented. The plasma was generated with a 40-mTorr fill of deuterium in a 3.81 cm radius discharge tube; 67% Z-preionization was followed by a main current discharge that produced a 23-kG peak magnetic field in 4.75 μsec. The electron density and temperature in the plasma column at the end of dynamic implosion were characterized by 1.0 x 10 16 cm -3 and 20 eV, respectively. This was followed by adiabatic compression which occurred with the particle and energy loss of interest. The diagnostics employed in this experiment were Thomson scattering, continuum radiation spectroscopy, local magnetic-field probes, local pressure probes, and diamagnetic loops. Axial temperature and density profiles were mapped from the coil into the end region

  6. Corticosteroid therapy in patients with non-arteritic anterior ischemic optic neuropathy.

    Science.gov (United States)

    Vidović, Tomislav; Cerovski, Branimir; Perić, Sanja; Kordić, Rajko; Mrazovac, Danijela

    2015-03-01

    Non-arteritic anterior ischemic optic neuropathy is one of the most common conditions affecting the optic nerve in the elderly. It may lead to severe visual loss. Typical symptoms are painless impairment of visual function accompanied by relative afferent pupillary defect, edema of the optic disc and visual field defects. Aim is to present 38 patients with nonarteritic anterior ischemic optic neuropathy who were treated with corticosteroid therapy. This prospective study involved 38 patients, 20 men and 18 women aged 60-75 years who were treated with corticosteroid therapy. The study included patients with visual acuity in the affected eye from 0.1 to 0.8 according to Snellen. Every patient underwent clinical examination, the Octopus 900 perimetry in G program, laboratory testing, while the compressive optic neuropathy was rule out with MSCT of the brain and orbits. The most common forms of visual field defect are altitudinal defect and diffuse depression. Corticosteroid therapy led to recovery in 65% of patient, in 30% of patients did not change, while the deterioration occurred in 5% of patients.

  7. Geometry dependence of magnetic and transport AC losses in Bi-2223/Ag tapes with different aspect ratios

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Luo, X M [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Chen, D X [ICREA and Grup Electromagnetisme, Departament de Fisica, Universitat Autonoma Barcelona, 08193 Bellaterra (Spain); Alamgir, A K M [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Collings, E W [MSE, Ohio State University, Columbus, OH 43210 (United States); Lee, E [MSE, Ohio State University, Columbus, OH 43210 (United States); Sumption, M D [MSE, Ohio State University, Columbus, OH 43210 (United States); Fang, J G [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Yi, H P [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Song, X H [Innova Superconductor Technology Co., Ltd, 7 Rongchang Dongjie, Longsheng Industrial Park, Beijing Economic and Technological Development Area, 100176 (China); Guo, S Q [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Liu, M L [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China); Xin, Y [Innopower Superconductor Cable Co., Ltd, 7 Rongchang Dongjie, Longsheng Industrial Park, Beijing Economic and Technological Development Area, 100176 (China); Han, Z [Applied Superconductivity Research Center, Tsinghua University, Beijing 100084 (China)

    2004-10-01

    On five Bi-2223/Ag tapes with different aspect ratios from 5 to 26, AC losses have been measured at 77 K while a parallel AC magnetic field or a perpendicular AC magnetic field or a longitudinal AC transport current is applied. It has been found that at any frequency the perpendicular magnetic losses per cycle increase, but the parallel magnetic losses per cycle and the transport losses per cycle decrease as the aspect ratio increases. These experimental results are in accord with theoretical results. Meanwhile, we investigated the geometry dependence of the decay time constant of coupling current and that of full penetration field.

  8. Geometry dependence of magnetic and transport AC losses in Bi-2223/Ag tapes with different aspect ratios

    International Nuclear Information System (INIS)

    Fang, J; Luo, X M; Chen, D X; Alamgir, A K M; Collings, E W; Lee, E; Sumption, M D; Fang, J G; Yi, H P; Song, X H; Guo, S Q; Liu, M L; Xin, Y; Han, Z

    2004-01-01

    On five Bi-2223/Ag tapes with different aspect ratios from 5 to 26, AC losses have been measured at 77 K while a parallel AC magnetic field or a perpendicular AC magnetic field or a longitudinal AC transport current is applied. It has been found that at any frequency the perpendicular magnetic losses per cycle increase, but the parallel magnetic losses per cycle and the transport losses per cycle decrease as the aspect ratio increases. These experimental results are in accord with theoretical results. Meanwhile, we investigated the geometry dependence of the decay time constant of coupling current and that of full penetration field

  9. Energy losses on tokamak startup

    International Nuclear Information System (INIS)

    Murray, J.G.; Rothe, K.E.; Bronner, G.

    1983-01-01

    During the startup of a tokamak reactor using poloidal field (PF) coils to induce plasma currents, the conducting structures carry induced currents. The associated energy losses in the circuits must be provided by the startup coils and the PF system. This paper provides quantitative and comparitive values for the energies required as a function of the thickness or resistivity of the torus shells

  10. Investigation of energy losses in low-coercivity resin-bonded magnets in alternating magnetic fields

    Science.gov (United States)

    Milov, E. V.; Sipin, I. A.; Milov, V. N.; Andreenko, A. S.; Balan, I. A.

    2017-01-01

    Energy losses during alternating remagnetization of low-coercitivity resin-bonded magnets and commercially produced electrical steels were studied experimentally. The studies were conducted on several samples of resin-bonded magnets with different manufacturing technologies and samples of electrical steel sheets of various thicknesses. The static and dynamic magnetic properties of the samples were measured on a vibration magnetometer and a specially designed apparatus, respectively. It was found that the studied samples of bonded magnets have a relatively high level of hysteresis losses associated with high coercivity, which reaches a value of 4-5 Oe. At the same time, the remagnetization losses due to the Foucault currents in the bonded magnets are considerably lower than in electrical steels. The measurement results show that bonded magnets at high frequencies of remagnetization, especially in high-rpm motors, can be competitive in comparison with electrical steels.

  11. Dielectric loss of strontium titanate thin films

    Science.gov (United States)

    Dalberth, Mark Joseph

    1999-12-01

    Interest in strontium titanate (STO) thin films for microwave device applications continues to grow, fueled by the telecommunications industry's interest in phase shifters and tunable filters. The optimization of these devices depends upon increasing the phase or frequency tuning and decreasing the losses in the films. Currently, the dielectric response of thin film STO is poorly understood through lack of data and a theory to describe it. We have studied the growth of STO using pulsed laser deposition and single crystal substrates like lanthanum aluminate and neodymium gallate. We have researched ways to use ring resonators to accurately measure the dielectric response as a function of temperature, electric field, and frequency from low radio frequencies to a few gigahertz. Our films grown on lanthanum aluminate show marked frequency dispersion in the real part of the dielectric constant and hints of thermally activated loss behavior. We also found that films grown with conditions that optimized the dielectric constant showed increased losses. In an attempt to simplify the system, we developed a technique called epitaxial lift off, which has allowed us to study films removed from their growth substrates. These free standing films have low losses and show obvious thermally activated behavior. The "amount of tuning," as measured by a figure of merit, KE, is greater in these films than in the films still attached to their growth substrates. We have developed a theory that describes the real and imaginary parts of the dielectric constant. The theory models the real part using a mean field description of the ionic motion in the crystal and includes the loss by incorporating the motion of charged defects in the films.

  12. Electrostatic ion confinement in a magnetic mirror field

    International Nuclear Information System (INIS)

    Nishida, Y.; Kawamata, S.; Ishii, K.

    1976-08-01

    The electrostatic ion stoppering at the mirror point is demonstrated experimentally in a magnetic mirror field. The ion losses from the mirror throat are decreased to about 15% of the initial losses in a rather high plasma density (10 10 0 13 cm -3 ). It is discussed as a confinement mechanism of ions that particles are reflected back adiabatically at the throat of the magnetic mirror field supplemented by DC electric field. (auth.)

  13. Examining Relativistic Electron Loss in the Outer Radiation Belt

    Science.gov (United States)

    Green, J. C.; Onsager, T. G.; O'Brien, P.

    2003-12-01

    Since the discovery of earth's radiation belts researchers have sought to identify the mechanisms that dictate the seemingly erratic relativistic electron flux levels in the outer belt. Contrary to intuition, relativistic electron flux levels do not always increase during geomagnetic storms even though these storms signify enhanced energy input from the solar wind to the magnetosphere [Reeves et al., 2003; O'Brien et al., 2001]. The fickle response of the radiation belt electrons to geomagnetic activity suggests that flux levels are determined by the outcome of a continuous competition between acceleration and loss. Some progress has been made developing and testing acceleration mechanisms but little is known about how relativistic electrons are lost. We examine relativistic electron losses in the outer belt focusing our attention on flux decrease events of the type first described by Onsager et al. [2002]. The study showed a sudden decrease of geosynchronous >2MeV electron flux occurring simultaneously with local stretching of the magnetic field. The decrease was first observed near 15:00 MLT and progressed to all local times after a period of ˜10 hours. Expanding on the work of Onsager et al. [2002], we have identified ˜ 51 such flux decrease events in the GOES and LANL data and present the results of a superposed epoch analysis of solar wind data, geomagnetic activity indicators, and locally measured magnetic field and plasma data. The analysis shows that flux decreases occur after 1-2 days of quiet condition. They begin when either the solar wind dynamic pressure increases or Bz turns southward pushing hot dense plasma earthward to form a partial ring current and stretched magnetic field at dusk. Adiabatic electron motion in response to the stretched magnetic field may explain the initial flux reduction; however, often the flux does not recover with the magnetic field recovery, indicating that true loss from the magnetosphere is occurring. Using Polar and

  14. A model on CME/Flare initiation: Loss of Equilibrium caused by mass loss of quiescent prominences

    Science.gov (United States)

    Miley, George; Chon Nam, Sok; Kim, Mun Song; Kim, Jik Su

    2015-08-01

    Coronal Mass Ejections (CMEs) model should give an answer to enough energy storage for giant bulk plasma into interplanetary space to escape against the sun’s gravitation and its explosive eruption. Advocates of ‘Mass Loading’ model (e.g. Low, B. 1996, SP, 167, 217) suggested a simple mechanism of CME initiation, the loss of mass from a prominence anchoring magnetic flux rope, but they did not associate the mass loss with the loss of equilibrium. The catastrophic loss of equilibrium model is considered as to be a prospective CME/Flare model to explain sudden eruption of magnetic flux systems. Isenberg, P. A., et al (1993, ApJ, 417, 368)developed ideal magnetohydrodynamic theory of the magnetic flux rope to show occurrence of catastrophic loss of equilibrium according to increasing magnetic flux transported into corona.We begin with extending their study including gravity on prominence’s material to obtain equilibrium curves in case of given mass parameters, which are the strengths of the gravitational force compared with the characteristic magnetic force. Furthermore, we study quasi-static evolution of the system including massive prominence flux rope and current sheet below it to obtain equilibrium curves of prominence’s height according to decreasing mass parameter in a properly fixed magnetic environment. The curves show equilibrium loss behaviors to imply that mass loss result in equilibrium loss. Released fractions of magnetic energy are greater than corresponding zero-mass case. This eruption mechanism is expected to be able to apply to the eruptions of quiescent prominences, which is located in relatively weak magnetic environment with 105 km of scale length and 10G of photospheric magnetic field.

  15. Ripple losses during ICRF heating in Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Eriksson, L.-G.; Bergeaud, V.; Chantant, M.; Martin, G.; Nguyen, F.; Reichle, R.; Vallet, J.C.; Delpeche, L.; Surle, F.

    2004-01-01

    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)

  16. Beam loss control in the LINAC4 design

    CERN Document Server

    Stovall, J; Crandall, K

    2010-01-01

    The Linac4 DTL reference design has been modified to reduce the power consumption in tank 1 by modifying the accelerating field and phase law. In addition we have adopted an FFDD focusing lattice throughout to minimize expected losses resulting from alignment errors. We have observed, however, that this design suffers from decreasing transverse acceptance and a sensitivity to misalignments that causes any expected beam loss to occcur at the high energy end of the DTL. In this note we investigate two solutions to increase the acceptance, decrease its sensitivity to misalignments and eliminate the potential for a beam-loss “bottleneck” at 50 MeV.

  17. 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.

  18. [Hearing loss and idoneity--the segnalation of noise-induced hearing loss hearing Loss].

    Science.gov (United States)

    Albera, Roberto; Dagna, Federico; Cassandro, Claudia; Canale, Andrea

    2011-01-01

    Work idoneity in hearing loss must be related to working ability and evolution risks. Working ability is referred to the difficulties found in speech comprehension and in signals perception. As regards hearing loss evolution it is necessary to define if the subject is affected by conductive or neurosensorial hearing loss. In conductive hearing loss it is necessary to evaluate entity and frequential distribution of the deficit. In neurosensorial hearing loss it is necessary to distinguish between noise-induced hearing loss and extraprofessional hearing loss. In noise-induced hearing loss the evolution risk is high if the noise exposure is less than 10-15 years or the actual noise exposure is louder than the former. In case of extraprofessional hearing loss the evolution risk is higher in presbycusis, endolymphatic hydrops and toxic hearing loss. The necessity to report the presence on professionale noise-induced hearing loss arises if audiometric threshold is more than 25 dB at 0.5-1-2-3-4 kHz and if it is verified the professional origine of hearing loss.

  19. Boundary between a plasma and a field with particle losses

    International Nuclear Information System (INIS)

    Konkhashbaev, I.K.; Zandman, I.S.; Ilinich, F.R.

    1978-01-01

    For open magnetic traps with β=1, the formation of plasma-field boundary (skin-layer) and the rate of the magnetic field fiffusion into plasma were investigated through the consideration of an evolution of a wide skin-layer. A large value of the mirror ratio is assumed for the sake of simplicity. The skin-layer structure is formed by two mechanisms: a mutual plasma-field diffusion tending to expand the boundary, and escape of particles trapped in the skin-layer region, along lines of force through the magnetic mirror, which tends to compress the boundary. It is shown that compression of the wide boundary occurs for the time of the order of the ion-ion collision time when the ion and electron temperatures change substantially. The final skin-layer width proved to be larger than a hybrid one, but smaller than the ion Larmour radius and depends slightly on initial temperatures. It has been established that the diffusion of the magnetic field into the plasma of magnetic trap has the character of a stationary wave of a width equal to the ion Larmour radius and of the velocity V approximately Vsub(Ti)/(ωsub(i)tausub(i))(Vsub(Ti) is the thermal ion velocity, ωsub(i), tausub(i) - the ion cyclotron frequency and collision time)

  20. Application of MUSLE for the prediction of phosphorus losses.

    Science.gov (United States)

    Noor, Hamze; Mirnia, Seyed Khalagh; Fazli, Somaye; Raisi, Mohamad Bagher; Vafakhah, Mahdi

    2010-01-01

    Soil erosion in forestlands affects not only land productivity but also the water body down stream. The Universal Soil Loss Equation (USLE) has been applied broadly for the prediction of soil loss from upland fields. However, there are few reports concerning the prediction of nutrient (P) losses based on the USLE and its versions. The present study was conducted to evaluate the applicability of the deterministic model Modified Universal Soil Loss Equation (MUSLE) to estimation of phosphorus losses in the Kojor forest watershed, northern Iran. The model was tested and calibrated using accurate continuous P loss data collected during seven storm events in 2008. Results of the original model simulations for storm-wise P loss did not match the observed data, while the revised version of the model could imitate the observed values well. The results of the study approved the efficient application of the revised MUSLE in estimating storm-wise P losses in the study area with a high level of agreement of beyond 93%, an acceptable estimation error of some 35%.

  1. 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.

  2. Quantifying the Impact of Seasonal and Short-term Manure Application Decisions on Phosphorus Loss in Surface Runoff.

    Science.gov (United States)

    Vadas, Peter A; Good, Laura W; Jokela, William E; Karthikeyan, K G; Arriaga, Francisco J; Stock, Melanie

    2017-11-01

    Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields and water quality degradation. Better information is needed on the risk of P loss from dairy manure applied in winter or when runoff is imminent. We used the SurPhos computer model and 108 site-years of weather and runoff data to assess the impact of these two practices on dissolved P loss. Model results showed that winter manure application can increase P loss by 2.5 to 3.6 times compared with non-winter applications, with the amount increasing as the average runoff from a field increases. Increased P loss is true for manure applied any time from late November through early March, with a maximum P loss from application in late January and early February. Shifting manure application to fields with less runoff can reduce P loss by 3.4 to 7.5 times. Delaying manure application when runoff is imminent can reduce P loss any time of the year, and sometimes quite significantly, but the number of times that application delays will reduce P loss is limited to only 3 to 9% of possible spreading days, and average P loss may be reduced by only 15% for winter-applied manure and 6% for non-winter-applied manure. Overall, long-term strategies of shifting manure applications to low runoff seasons and fields can potentially reduce dissolved P loss in runoff much more compared with near-term, tactical application decisions of avoiding manure application when runoff is imminent. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. submitter Hysteresis Losses and Effective $J_{c}(B)$ Scaling Law for ITER Nb$_{3}$Sn Strands

    CERN Document Server

    Seiler, E; Bordini, B; Bottura, L; Bessette, D; Vostner, A; Devred, A

    2016-01-01

    Hysteresis losses of five Nb$_{3}$Sn International Thermonuclear Experimental Reactor reference strands were investigated by means of magnetization loop measurements in a vibrating sample magnetometer in a perpendicularly applied magnetic field. The magnetization loops were recorded while continuously sweeping the applied field between the extreme values $±B_m$, covering a wide range of maximum applied fields (0.2-10 T). In this paper, we compare the directly determined hysteresis losses based on the area of the smaller measured loops and the losses calculated by the integration of the width ΔM of the $B_m$ = 10 T magnetization loop. A suitable fitting function is proposed to describe the ΔM(B) dependence, which leads, for each strand, to an excellent agreement with the experimentally determined hysteresis losses, magnetization, and pinning force. Transport critical current measurements in a perpendicularly applied magnetic field were also performed for all the strands, and on the basis of the comparison w...

  4. Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

    Science.gov (United States)

    Zhao, Wenqiang; Reich, Peter B.; Yu, Qiannan; Zhao, Ning; Yin, Chunying; Zhao, Chunzhang; Li, Dandan; Hu, Jun; Li, Ting; Yin, Huajun; Liu, Qing

    2018-04-01

    Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523-4685 m) on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3-47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2-75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub) could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m), likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer), their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most important factor explaining the overall leaf C : N : P variations

  5. Potential and Limitations of Low-Cost Unmanned Aerial Systems for Monitoring Altitudinal Vegetation Phenology in the Tropics

    Science.gov (United States)

    Silva, T. S. F.; Torres, R. S.; Morellato, P.

    2017-12-01

    Vegetation phenology is a key component of ecosystem function and biogeochemical cycling, and highly susceptible to climatic change. Phenological knowledge in the tropics is limited by lack of monitoring, traditionally done by laborious direct observation. Ground-based digital cameras can automate daily observations, but also offer limited spatial coverage. Imaging by low-cost Unmanned Aerial Systems (UAS) combines the fine resolution of ground-based methods with and unprecedented capability for spatial coverage, but challenges remain in producing color-consistent multitemporal images. We evaluated the applicability of multitemporal UAS imaging to monitor phenology in tropical altitudinal grasslands and forests, answering: 1) Can very-high resolution aerial photography from conventional digital cameras be used to reliably monitor vegetative and reproductive phenology? 2) How is UAS monitoring affected by changes in illumination and by sensor physical limitations? We flew imaging missions monthly from Feb-16 to Feb-17, using a UAS equipped with an RGB Canon SX260 camera. Flights were carried between 10am and 4pm, at 120-150m a.g.l., yielding 5-10cm spatial resolution. To compensate illumination changes caused by time of day, season and cloud cover, calibration was attempted using reference targets and empirical models, as well as color space transformations. For vegetative phenological monitoring, multitemporal response was severely affected by changes in illumination conditions, strongly confounding the phenological signal. These variations could not be adequately corrected through calibration due to sensor limitations. For reproductive phenology, the very-high resolution of the acquired imagery allowed discrimination of individual reproductive structures for some species, and its stark colorimetric differences to vegetative structures allowed detection of the reproductive timing on the HSV color space, despite illumination effects. We conclude that reliable

  6. 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)

    Herwig, Heinz; Schmandt, Bastian

    2013-01-01

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

  7. 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.

  8. The effect of surface grain reversal on the AC losses of sintered Nd–Fe–B permanent magnets

    International Nuclear Information System (INIS)

    Moore, Martina; Roth, Stefan; Gebert, Annett; Schultz, Ludwig; Gutfleisch, Oliver

    2015-01-01

    Sintered Nd–Fe–B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd–Fe–B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory. - Highlights: • The eddy current losses of sintered Nd–Fe–B magnets were measured. • Field amplitudes up to 113 mT over the frequency range 50 to 1000 Hz were applied. • The Nd–Fe–B magnets showed significant hysteresis losses at low amplitudes (∼100 mT). • The source of such hysteresis losses in sintered Nd–Fe–B magnets was identified. • Two magnet grades with different dysprosium content were investigated

  9. The effect of surface grain reversal on the AC losses of sintered Nd–Fe–B permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Martina, E-mail: m.moore@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); Roth, Stefan; Gebert, Annett [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); Schultz, Ludwig [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); TU Dresden, Institute for Materials Science, 01062 Dresden (Germany); Gutfleisch, Oliver [TU Darmstadt, Department of Materials Science, Alarich-Weiß-Str. 16, 64287 Darmstadt (Germany); Fraunhofer Project Group for Materials Recycling and Resource Strategies IWKS, 63457 Hanau (Germany)

    2015-02-01

    Sintered Nd–Fe–B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd–Fe–B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory. - Highlights: • The eddy current losses of sintered Nd–Fe–B magnets were measured. • Field amplitudes up to 113 mT over the frequency range 50 to 1000 Hz were applied. • The Nd–Fe–B magnets showed significant hysteresis losses at low amplitudes (∼100 mT). • The source of such hysteresis losses in sintered Nd–Fe–B magnets was identified. • Two magnet grades with different dysprosium content were investigated.

  10. End-shorting and electric field in edge plasmas with application to field-reversed configurations

    International Nuclear Information System (INIS)

    Steinhauer, Loren C.

    2002-01-01

    The shorting of open field lines where they intersect external boundaries strongly modifies the transverse electric field all along the field lines. The modified electric field is found by an extension of the familiar Boltzmann relation for the electric potential. This leads to a prediction of the electric drift. Flow generation by electrical shorting is applied here to three aspects of elongated field-reversed configurations: plasma rotation rate; the particle-loss spin-up mechanism; and the sustainability of the rotating magnetic field current drive method

  11. Particle transort in field-reversed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Tuszewski, M.; Linford, R.K.; Lipson, J.; Sgro, A.G.

    1981-01-01

    A field reversed configuration (FRC) is a compact toroid that contains no toroidal field. These plasmas are observed to be grossly stable for about 10-100 ..mu..sec. The lifetimes appear limited by an n = 2 rotational instability which may be caused by particle loss. Particle transport is therefore an important issue for these configurations. We investigate particle loss with a steady-state, 1-D model which approximates the experimental observation of elongated FRC equilibrium with about constant separatrix radius.

  12. AC magnetization loss characteristics of HTS striated coated conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O; Alamgir, A K M; Sekizawa, S; Miyagi, D

    2008-01-01

    AC magnetization losses in subdivided CC (Coated Conductor) with magnetic substrate were experimentally investigated comparing with those in subdivided CC with non-magnetic substrate for an AC external magnetic field perpendicular to the wide face of the CC. It is well known that the subdivision is effective to reduce magnetization losses in CC with non-magnetic substrate. The experimental results show that the subdivision is also effective for the CC with magnetic substrate and that the level of reduction of the losses by the subdivisions is almost the same as that of non-magnetic substrate CCs. It is concluded from the experimental results that the magnetic property of the substrate does not affect the magnetization losses in the subdivided conductor in the range of the experiment where the amplitude of the AC external magnetic field is 0 ∼ 0.1 T and the frequency is 16 ∼ 86 Hz

  13. AC magnetization loss characteristics of HTS striated coated conductors with magnetic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, O; Alamgir, A K M; Sekizawa, S [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa, 240-8501 (Japan); Miyagi, D [Okayama University, 1-1, Tsushima-Naka, 1-Chome, Okayama 700-8530 (Japan)], E-mail: Osami-t@ynu.ac.jp

    2008-02-01

    AC magnetization losses in subdivided CC (Coated Conductor) with magnetic substrate were experimentally investigated comparing with those in subdivided CC with non-magnetic substrate for an AC external magnetic field perpendicular to the wide face of the CC. It is well known that the subdivision is effective to reduce magnetization losses in CC with non-magnetic substrate. The experimental results show that the subdivision is also effective for the CC with magnetic substrate and that the level of reduction of the losses by the subdivisions is almost the same as that of non-magnetic substrate CCs. It is concluded from the experimental results that the magnetic property of the substrate does not affect the magnetization losses in the subdivided conductor in the range of the experiment where the amplitude of the AC external magnetic field is 0 {approx} 0.1 T and the frequency is 16 {approx} 86 Hz.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-15

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

  15. 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.

  16. Operating point resolved loss computation in electrical machines

    Directory of Open Access Journals (Sweden)

    Pfingsten Georg Von

    2016-03-01

    Full Text Available Magnetic circuits of electromagnetic energy converters, such as electrical machines, are nowadays highly utilized. This proposition is intrinsic for the magnetic as well as the electric circuit and depicts that significant enhancements of electrical machines are difficult to achieve in the absence of a detailed understanding of underlying effects. In order to improve the properties of electrical machines the accurate determination of the locally distributed iron losses based on idealized model assumptions solely is not sufficient. Other loss generating effects have to be considered and the possibility being able to distinguish between the causes of particular loss components is indispensable. Parasitic loss mechanisms additionally contributing to the total losses originating from field harmonics, non-linear material behaviour, rotational magnetizations, and detrimental effects caused by the manufacturing process or temperature, are not explicitly considered in the common iron-loss models, probably even not specifically contained in commonly used calibration factors. This paper presents a methodology being able to distinguish between different loss mechanisms and enables to individually consider particular loss mechanisms in the model of the electric machine. A sensitivity analysis of the model parameters can be performed to obtain information about which decisive loss origin for which working point has to be manipulated by the electromagnetic design or the control of the machine.

  17. Rotational loss of a ring-shaped flywheel supported by high Tc superconducting levitation

    International Nuclear Information System (INIS)

    Teshima, Hidekazu; Tawara, Taichi; Shimada, Ryuichi.

    1997-01-01

    This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T c superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

  18. Dependence of the ac loss on the aspect ratio in a cable in conduit conductor

    International Nuclear Information System (INIS)

    Cau, F; Bruzzone, P

    2010-01-01

    The coupling current loss in rectangular superconducting cables is strictly dependent on their aspect ratio, which has an impact on the area linked by the field variation and consequently on the currents induced between strands. The relation between the ac loss and aspect ratio is studied with reference to the testing of three short cable in conduit conductor (CICC) samples at the SULTAN test facility. The first conductor is a 25 kA NbTi cable for the JT60-SA tokamak; the second is a 20 kA Nb 3 Sn cable for the HZB hybrid magnet. The last CICC is a 68 kA Nb 3 Sn cable with layout similar to that of the ITER toroidal field (TF) conductor (called the 'European toroidal field (EUTF) alternate'). All the samples are assembled with two conductor sections differing only in their orientation with respect to the external variable field. In the first and third samples, the cable of one leg is rotated by 90 0 , while in the HZB sample it is rotated by 45 0 with respect to the other leg. The ac loss is measured at the SULTAN test facility using a gas flow calorimetric method. A sample length of 39 cm is exposed to a sinusoidal field with an amplitude of ± 0.3 or ± 0.2 T (depending on the superconductor) and frequency variable in the range 0.1-0.8 Hz. A background field of 2 T perpendicular both to the sinusoidal field and to the sample axis is also applied. The ac loss is assessed by measuring the variation of the He enthalpy, assuming the metal enthalpy to be negligible. The loss curve for both legs is discussed in terms of the respective aspect ratios and the results, including data from former test campaigns, are compared with the aim of finding an analytical relation between the loss and the conductor dimensions.

  19. Broadband magnetic losses of nanocrystalline ribbons and powder cores

    Energy Technology Data Exchange (ETDEWEB)

    Beatrice, Cinzia, E-mail: c.beatrice@inrim.it [Istituto Nazionale di Ricerca Metrologica, Nanoscience and Materials Division, Torino (Italy); Dobák, Samuel [Institute of Physics, Faculty of Science, P.J. Šafárik University, Košice (Slovakia); Ferrara, Enzo; Fiorillo, Fausto [Istituto Nazionale di Ricerca Metrologica, Nanoscience and Materials Division, Torino (Italy); Ragusa, Carlo [Politecnico di Torino, Energy Department, Torino (Italy); Füzer, Ján; Kollár, Peter [Institute of Physics, Faculty of Science, P.J. Šafárik University, Košice (Slovakia)

    2016-12-15

    Finemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally field-annealed ribbons. This is understood in terms of rotation-dominated magnetization process in the low-anisotropy material. Intergrain eddy currents are responsible for the fast increase of the losses with frequency and for early permeability relaxation of the powder cores. Evidence for resonant phenomena at high frequencies and for the ensuing inadequate role of the static magnetic constitutive equation of the material in solving the magnetization dynamics via the Maxwell's diffusion equation of the electromagnetic field is provided. It is demonstrated that, by taking the Landau–Lifshitz–Gilbert equation as a constitutive relation, the excellent frequency response of the transverse anisotropy ribbons can be described by analytical method.

  20. Loss-Aversion or Loss-Attention: The Impact of Losses on Cognitive Performance

    Science.gov (United States)

    Yechiam, Eldad; Hochman, Guy

    2013-01-01

    Losses were found to improve cognitive performance, and this has been commonly explained by increased weighting of losses compared to gains (i.e., loss aversion). We examine whether effects of losses on performance could be modulated by two alternative processes: an attentional effect leading to increased sensitivity to task incentives; and a…

  1. Permanent Magnet Eddy Current Loss Analysis of a Novel Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Zhang, Yuqiu; Lu, Kaiyuan; Ye, Yunyue

    2012-01-01

    In this paper, a new motor integrated permanent magnet gear (MIPMG) is discussed. The focus is on eddy current loss analysis associated to permanent magnets (PMs). A convenient model of MIPMG is provided based on 2-D field-motion coupled time-stepping finite element method for transient eddy...... current analysis. The model takes the eddy current effect of PMs into account in determination of the magnetic field in the air-gap and in the magnet regions. The eddy current losses generated in the magnets are properly interpreted. Design improvements for reducing the eddy current losses are suggested...

  2. A Small Disc Area Is a Risk Factor for Visual Field Loss Progression in Primary Open-Angle Glaucoma: The Glaucoma Stereo Analysis Study.

    Science.gov (United States)

    Kitaoka, Yasushi; Tanito, Masaki; Yokoyama, Yu; Nitta, Koji; Katai, Maki; Omodaka, Kazuko; Nakazawa, Toru

    2018-01-01

    The Glaucoma Stereo Analysis Study, a cross-sectional multicenter collaborative study, used a stereo fundus camera (nonmyd WX) to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients. We compared the associations of each parameter between the visual field loss progression group and no-progression group. The study included 187 eyes of 187 patients with primary open-angle glaucoma or normal-tension glaucoma. We divided the mean deviation (MD) slope values of all patients into the progression group (field progression and patient characteristics or each ONH parameter were analyzed with Spearman's rank correlation coefficient. The MD slope averages in the progression group and no-progression group were -0.58 ± 0.28 dB/year and 0.05 ± 0.26 dB/year, respectively. Among disc parameters, vertical disc width (diameter), disc area, cup area, and cup volume in the progression group were significantly less than those in the no-progression group. Logistic regression analysis revealed a significant association between the visual field progression and disc area (odds ratio 0.49/mm 2 disc area). A smaller disc area may be associated with more rapid glaucomatous visual field progression.

  3. Comprehensive nitrogen budgets for controlled tile drainage fields in eastern ontario, Canada.

    Science.gov (United States)

    Sunohara, M D; Craiovan, E; Topp, E; Gottschall, N; Drury, C F; Lapen, D R

    2014-03-01

    Excessive N loading from subsurface tile drainage has been linked to water quality degradation. Controlled tile drainage (CTD) has the potential to reduce N losses via tile drainage and boost crop yields. While CTD can reduce N loss from tile drainage, it may increase losses through other pathways. A multiple-year field-scale accounting of major N inputs and outputs during the cropping season was conducted on freely drained and controlled tile drained agricultural fields under corn ( L.)-soybean [ (L.) Merr.] production systems in eastern Ontario, Canada. Greater predicted gaseous N emissions for corn and soybean and greater observed lateral seepage N losses were observed for corn and soybean fields under CTD relative to free-draining fields. However, observed N losses from tile were significantly lower for CTD fields, in relation to freely drained fields. Changes in residual soil N were essentially equivalent between drainage treatments, while mass balance residual terms were systematically negative (slightly more so for CTD). Increases in plant N uptake associated with CTD were observed, probably resulting in higher grain yields for corn and soybean. This study illustrates the benefits of CTD in decreasing subsurface tile drainage N losses and boosting crop yields, while demonstrating the potential for CTD to increase N losses via other pathways related to gaseous emissions and groundwater seepage. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Measurements of Beam Ion Loss from the Compact Helical System

    International Nuclear Information System (INIS)

    Darrow, D.S.; Isobe, M.; Kondo, Takashi; Sasao, M.

    2010-01-01

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  5. Mobile phone induced sensorineural hearing loss

    International Nuclear Information System (INIS)

    Al-Dousary, Surayie H.

    2007-01-01

    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)

  6. Behavioral Animal Model of the Emotional Response to Tinnitus and Hearing Loss.

    Science.gov (United States)

    Lauer, Amanda M; Larkin, Gail; Jones, Aikeen; May, Bradford J

    2018-02-01

    Increased prevalence of emotional distress is associated with tinnitus and hearing loss. The underlying mechanisms of the negative emotional response to tinnitus and hearing loss remain poorly understood, and it is challenging to disentangle the emotional consequences of hearing loss from those specific to tinnitus in listeners experiencing both. We addressed these questions in laboratory rats using three common rodent anxiety screening assays: elevated plus maze, open field test, and social interaction test. Open arm activity in the elevated plus maze decreased substantially after one trial in controls, indicating its limited utility for comparing pre- and post-treatment behavior. Open field exploration and social interaction behavior were consistent across multiple sessions in control animals. Individual sound-exposed and salicylate-treated rats showed a range of phenotypes in the open field, including reduced entries into the center in some subjects and reduced locomotion overall. In rats screened for tinnitus, less locomotion was associated with higher tinnitus scores. In salicylate-treated animals, locomotion was correlated with age. Sound-exposed and salicylate-treated rats also showed reduced social interaction. These results suggest that open field exploratory activity is a selective measure for identifying tinnitus distress in individual animals, whereas social interaction reflects the general effects of hearing loss. This animal model will facilitate future studies of the structural and functional changes in the brain pathways underlying emotional distress associated with hearing dysfunction, as well as development of novel interventions to ameliorate or prevent negative emotional responses.

  7. Neoclassical transport and radial electric fields in TJ-K

    International Nuclear Information System (INIS)

    Rahbarnia, K.; Greiner, F.; Ramisch, M.; Stroth, U.; Greiner, F.

    2003-01-01

    The neoclassical transport is investigated in the torsatron TJ-K, which is operated with a low-temperature plasma. In the low-collisionality regime neoclassical losses are not intrinsically ambipolar, leading to the formation of a radial electric field which acts on both neoclassical and turbulent transport. This electric field is measured with a combination of Langmuir and emissive probes. The data are compared with the ambipolar electric field calculated with an analytic model. The experimental fields are positive and larger than the calculated ones. Direct losses of the fast electrons might explain this discrepancy. (orig.)

  8. Flux loss and heating during the formation of a field-reversed configuration

    International Nuclear Information System (INIS)

    Sgro, A.G.; Armstrong, W.T.; Lipson, J.; Tuszewski, M.G.; Cochrane, J.C.

    1982-01-01

    The simulated time evolution of magnetic field profiles and trapped flux in a field-reversed configuration, when compared with the experiment, implies that the rapid decay of the initial reversed flux is due to a resistivity that is anomalously enhanced over its classical value. A tenuous plasma between the field-reversed configuration and the wall carries a significant fraction of the current, and about half of the anomalous Joule heating must be deposited directly in the ions in order to calculate the correct ion temperature. The fractional flux retention is most sensitive to an increase of applied bias field

  9. Infiltration on mountain slopes: a comparison of three environments.

    Science.gov (United States)

    Carol P. Harden*; P. Delmas Scruggs

    2003-01-01

    Water is well established as a major driver of the geomorphic change that eventually reduces mountains to lower relief landscapes. Nonetheless, within the altitudinal limits of continuous vegetation in humid climates, water is also an essential factor in slope stability. In this paper, we present results from field experiments to determine infiltration rates at...

  10. Patterns of functional vision loss in glaucoma determined with archetypal analysis

    Science.gov (United States)

    Elze, Tobias; Pasquale, Louis R.; Shen, Lucy Q.; Chen, Teresa C.; Wiggs, Janey L.; Bex, Peter J.

    2015-01-01

    Glaucoma is an optic neuropathy accompanied by vision loss which can be mapped by visual field (VF) testing revealing characteristic patterns related to the retinal nerve fibre layer anatomy. While detailed knowledge about these patterns is important to understand the anatomic and genetic aspects of glaucoma, current classification schemes are typically predominantly derived qualitatively. Here, we classify glaucomatous vision loss quantitatively by statistically learning prototypical patterns on the convex hull of the data space. In contrast to component-based approaches, this method emphasizes distinct aspects of the data and provides patterns that are easier to interpret for clinicians. Based on 13 231 reliable Humphrey VFs from a large clinical glaucoma practice, we identify an optimal solution with 17 glaucomatous vision loss prototypes which fit well with previously described qualitative patterns from a large clinical study. We illustrate relations of our patterns to retinal structure by a previously developed mathematical model. In contrast to the qualitative clinical approaches, our results can serve as a framework to quantify the various subtypes of glaucomatous visual field loss. PMID:25505132

  11. Filament bundle location influence on coupling losses in superconducting composites

    International Nuclear Information System (INIS)

    Ito, Daisuke; Koizumi, Misao; Hamajima, Takataro; Nakane, Fumoto.

    1983-01-01

    The ac losses in multifilamentary superconducting composites with different superconducting filament bundle positions have been measured using the magnetization method in order to reveal the relation between filament bundle position and coupling losses. Loss components depending on dB/dt in a mixed matrix superconducting composite, whose filament bundle is located in a central region surrounded by an outer stabilizing copper sheath, has been compared with another superconducting composite whose stabilizing copper is located in a central region surrounded by an outer filament bundle. In both conductors, key parameters, such as filament twistpitch, wire diameter and amount of copper stabilizer, were almost the same. Applied magnetic field is 2 Tesla with 0.05-2 Tesla/sec field change rate. Experimental results indicate that coupling losses between filaments in the composite with the filament bundle located in the central region is smaller than the composite with the filament bundle located in the outer region. A similar conclusion was reached theoretically by B. Truck. Coupling loss values obtained by the experiment show good agreement with calculated values with the equations proposed by B. Truck. It is also pointed out that a copper stabilizer, divided by the CuNi barrier into small regions, like a honeycomb, causes anomalous increasing in the copper resistivity due to Ni diffusion during heat treatment. (author)

  12. Combined Influence of Strain and Heat Loss on Turbulent Premixed Flame Stabilization

    KAUST Repository

    Tay-Wo-Chong, Luis

    2015-11-16

    The present paper argues that the prediction of turbulent premixed flames under non-adiabatic conditions can be improved by considering the combined effects of strain and heat loss on reaction rates. The effect of strain in the presence of heat loss on the consumption speed of laminar premixed flames was quantified by calculations of asymmetric counterflow configurations (“fresh-to-burnt”) with detailed chemistry. Heat losses were introduced by setting the temperature of the incoming stream of products on the “burnt” side to values below those corresponding to adiabatic conditions. The consumption speed decreased in a roughly exponential manner with increasing strain rate, and this tendency became more pronounced in the presence of heat losses. An empirical relation in terms of Markstein number, Karlovitz Number and a non-dimensional heat loss parameter was proposed for the combined influence of strain and heat losses on the consumption speed. Combining this empirical relation with a presumed probability density function for strain in turbulent flows, an attenuation factor that accounts for the effect of strain and heat loss on the reaction rate in turbulent flows was deduced and implemented into a turbulent combustion model. URANS simulations of a premixed swirl burner were carried out and validated against flow field and OH chemiluminescence measurements. Introducing the effects of strain and heat loss into the combustion model, the flame topology observed experimentally was correctly reproduced, with good agreement between experiment and simulation for flow field and flame length.

  13. Features of change of permanent snow patches in the Mongun-Taiga Massif, 1966–2011

    Directory of Open Access Journals (Sweden)

    D. A. Ganyushkin

    2013-01-01

    Full Text Available The article is dedicated to perennial snow patches of Mongun-Taiga mountain massif (south-western Tuva, their morphology, present state and dynamics over the last 45 years. We created a scheme of snow patch classification with regard to genesis of relief and position on the slopes. Dynamics of snow patches is analyzed for periods between several time points – 1966 (on basis of aerial photos, 2000, 2007–2008 and 2011 (on basis of field measurements and observations. From 1966 to 2008 the number of snow patches decreased by 4 times, the total area – by 15 times, the altitudinal zone of snow patches moved 250–300 m up. In 2008–2011 the altitudinal zone of snow patches partly recovered, its lower limit moved 250 m down, periglacial snow patches recovered, a new type – snow patches of buried ice and debris-covered glaciers appeared. It could be the first face of the process of small glaciers recovery in the massif. Using the changes of the altitudinal position of snow patches in comparison with data of the closest meteorological station we estimated the amount of annual precipitation, critical for the existence of local snow patches.

  14. Finite-element analysis and comparison of the AC loss performance of BSCCO and YBCO conductors

    International Nuclear Information System (INIS)

    Stavrev, Svetlomir; Grilli, Francesco; Dutoit, Bertrand; Ashworth, Stephen

    2006-01-01

    The AC loss performance of two BSCCO and two YBCO conductors of different geometry, characterized by the same self-field critical current of 150 A, is analysed and compared quantitatively. The comparison is made using the finite-element method with a nonlinear B-dependent E-J relation. A new shell-region model is utilised for the simulations of thin YBCO strips. Different AC working conditions are simulated: self-field, applied external field, and combined transport current and external perpendicular field application. Magnetic field and current density profiles are investigated in order to illustrate the reasons for the loss difference in the conductors. Depending on the application, the advantages of using BSCCO or YBCO conductors with specific geometry are outlined

  15. Losses in magnetic flux compression generators: Part 2, Radiation losses

    International Nuclear Information System (INIS)

    Fowler, C.M.

    1988-06-01

    This is the second monograph devoted to the analysis of flux losses in explosive driven magnetic flux compression generators. In the first monograph, flux losses from magnetic field penetration into conductor walls was studied by conventional diffusion theory. In the present report flux loss by radiation from the outer conductor walls is treated. Flux leakage rates through walls of finite thickness are first obtained by diffusion theory. It is shown, for normal wall thicknesses, that flux leakage is determined essentially by the wall conductance, defined as the product of wall thickness and wall conductivity. This remains true when the wall thickness is reduced to zero at unchanged conductance. In this case the wall is said to be coalesced. Solutions for a cavity bounded by a perfect conductor on one side and a coalesced wall on the other are then obtained using the complete Maxwell wave equations in both the cavity and free space beyond the coalesced wall. Several anomalies, noted earlier, that arise from diffusion analysis are resolved by the wave treatment. Conditions for the validity of the diffusion treatment are noted, and an expression is obtained within the framework of diffusion theory for energy radiated into space from the cavity walls. The free space wave equations are solved by using the method of characteristics in both the cavity and free space regions. An extension of the characteristic method to situations where the constitutive relations are non-linear is outlined in an appendix. For a special class of these relations, Riemann-like invariants are determined explicitly and used to solve a particular example

  16. Tolerable Beam Loss at High-Intensity Machines

    International Nuclear Information System (INIS)

    Krivosheev, Oleg E.; Mokhov, Nikolai V.

    2000-01-01

    Tolerable beam losses are estimated for high-intensity ring accelerators with proton energy of 3 to 16 GeV. Dependence on beam energy, lattice and magnet geometry is studied via full Monte Carlo MARS14 simulations in lattice elements, shielding, tunnel and surrounding dirt with realistic geometry, materials and magnetic fields

  17. Low ac loss geometries in YBCO coated conductors and impact on conductor stability

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, Robert C [ORNL; List III, Frederick Alyious [ORNL; Paranthaman, Mariappan Parans [ORNL; Rupich, M. W. [American Superconductor Corporation, Westborough, MA; Zhang, W. [American Superconductor Corporation, Westborough, MA; Xie, Y. Y. [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. While ac loss reduction was achieved with YBCO filaments created through laser scribing and inkjet deposition, the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders. To better determine the practicality of these methods from a stability point of view, a numerical analysis was carried out to determine the influence of bridging and splicing on stability of a YBCO coated conductor for both liquid nitrogen-cooled and conduction cooled geometries.

  18. Silage review: Factors affecting dry matter and quality losses in silages.

    Science.gov (United States)

    Borreani, G; Tabacco, E; Schmidt, R J; Holmes, B J; Muck, R E

    2018-05-01

    An overview was made of dry matter (DM) and quality losses that occur during the ensiling process from the field through the feeding phase. The aim was to review the relevant published literature of the last 15 yr focusing on developments achieved after the publication of the book Silage Science and Technology. This review discusses the factors affecting DM and quality losses in terms of field and pre-ensiling conditions, respiration and temperature at ensiling, fermentation patterns, methods of covering and weighting the silage cover, and management of aerobic deterioration. The possibility of reducing DM and quality losses during the ensiling process requires knowledge of how to measure losses on farm and establish the status of the silage during the feed-out phase, implementing the most effective management practices to avoid air exposure during conservation and reduce silage aerobic deterioration during feeding. The paper concludes with future perspectives and recommended management practices to reduce losses and increase efficiency over the whole ensiling process in view of increasing sustainability of the livestock production chain. The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  19. Coupled transport in field-reversed configurations

    Science.gov (United States)

    Steinhauer, L. C.; Berk, H. L.; TAE Team

    2018-02-01

    Coupled transport is the close interconnection between the cross-field and parallel fluxes in different regions due to topological changes in the magnetic field. This occurs because perpendicular transport is necessary for particles or energy to leave closed field-line regions, while parallel transport strongly affects evolution of open field-line regions. In most toroidal confinement systems, the periphery, namely, the portion with open magnetic surfaces, is small in thickness and volume compared to the core plasma, the portion with closed surfaces. In field-reversed configurations (FRCs), the periphery plays an outsized role in overall confinement. This effect is addressed by an FRC-relevant model of coupled particle transport that is well suited for immediate interpretation of experiments. The focus here is particle confinement rather than energy confinement since the two track together in FRCs. The interpretive tool yields both the particle transport rate χn and the end-loss time τǁ. The results indicate that particle confinement depends on both χn across magnetic surfaces throughout the plasma and τǁ along open surfaces and that they provide roughly equal transport barriers, inhibiting particle loss. The interpretation of traditional FRCs shows Bohm-like χn and inertial (free-streaming) τǁ. However, in recent advanced beam-driven FRC experiments, χn approaches the classical rate and τǁ is comparable to classic empty-loss-cone mirrors.

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

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.

    1997-07-01

    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

  1. 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

  2. A core-monitoring based methodology for predictions of graphite weight loss in AGR moderator bricks

    Energy Technology Data Exchange (ETDEWEB)

    McNally, K., E-mail: kevin.mcnally@hsl.gsi.gov.uk [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Warren, N. [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Fahad, M.; Hall, G.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom)

    2017-04-01

    Highlights: • A statistically-based methodology for estimating graphite density is presented. • Graphite shrinkage is accounted for using a finite element model. • Differences in weight loss forecasts were found when compared to the existing model. - Abstract: Physically based models, resolved using the finite element (FE) method are often used to model changes in dimensions and the associated stress fields of graphite moderator bricks within a reactor. These models require inputs that describe the loading conditions (temperature, fluence and weight lossfield variables’), and coded relationships describing the behaviour of graphite under these conditions. The weight loss field variables are calculated using a reactor chemistry/physics code FEAT DIFFUSE. In this work the authors consider an alternative data source of weight loss: that from a longitudinal dataset of density measurements made on small samples trepanned from operating reactors during statutory outages. A nonlinear mixed-effect model is presented for modelling the age and depth-related trends in density. A correction that accounts for irradiation-induced dimensional changes (axial and radial shrinkage) is subsequently applied. The authors compare weight loss forecasts made using FEAT DIFFUSE with those based on an alternative statistical model for a layer four moderator brick for the Hinkley Point B, Reactor 3. The authors compare the two approaches for the weight loss distribution through the brick with a particular focus on the interstitial keyway, and for the average (over the volume of the brick) weight loss.

  3. Acceleration and energy loss in N = 4 SYM

    International Nuclear Information System (INIS)

    Chernicoff, Mariano; Gueijosa, Alberto

    2009-01-01

    This contribution is based on two talks given at the XIII Mexican School of Particles and Fields. We revisit some of the results presented in [19], concerning the rate of energy loss of an accelerating quark in strongly-coupled N = 4 super-Yang-Mills.

  4. Acceleration and energy loss in N = 4 SYM

    Science.gov (United States)

    Chernicoff, Mariano; Güijosa, Alberto

    2009-04-01

    This contribution is based on two talks given at the XIII Mexican School of Particles and Fields. We revisit some of the results presented in [19], concerning the rate of energy loss of an accelerating quark in strongly-coupled N = 4 super-Yang-Mills.

  5. Experimental and theoretical investigations of losses in a multifilament composite subjected

    International Nuclear Information System (INIS)

    Lefevre, F.; Turck, B.

    1980-10-01

    In a twisted multifilament composite subjected to transient axial fields three kinds of currents are induced: azimuthal currents in the matrix, azimuthal currents and coupling longitudinal currents in the filaments. Considering only the currents in the filament themselves, the hysteretic losses due to the azimuthal component Jsub(c) of the critical current density are usually the largest. However, when the coupling longitudinal currents flow in the outer layers of filaments in the same direction than the transport current their contribution become preponderant. Again, the theory shows three regimes depending only on the ratio of the amplitude of the changing field over a given threshold field, proportional to the twist pitch length of the composite. Experimental results clearly confirm the theory, in particular the increase of losses with transport current in a multifilament when only little effect was observed in a monofilament

  6. A model for particle and heat losses by type I edge localized modes

    International Nuclear Information System (INIS)

    Tokar, M Z; Gupta, A; Kalupin, D; Singh, R

    2007-01-01

    A model to estimate the particle and energy losses caused in tokamaks by type I edge localized modes (ELMs) is proposed. This model is based on the assumption that the increase in transport by ELM is due to flows along magnetic field lines perturbed by ballooning-peeling MHD modes. The model reproduces well the experimentally found variation of losses with the plasma collisionality ν*, namely, the weak dependence of the particle loss and significant reduction of the energy loss with increasing ν*. It is argued that the electron parallel heat conductivity is dominating in the energy loss at not very large ν*

  7. Loss-free neutron polarization

    International Nuclear Information System (INIS)

    Mueller, S.; Badurek, G.

    2001-01-01

    Full text: The so-called concept of 'dynamical' neutron polarization should allow to polarize a beam of thermal or cold neutrons without loosing even one particle. It is based upon the spin-dependent energy splitting of monochromatic neutrons in a NMR-like arrangement of crossed static and oscillating magnetic fields, which causes different interaction times of the two opposite spin states with a subsequent static precession field. If this Larmor rotation is stopped at the moment when the two states are oriented parallel to a given direction, the beam will be fully polarized, on the cost of a tiny energy difference between the two states, however. At pulsed neutron sources this method should even allow loss-free polarization of polychromatic neutrons, if by a suitably chosen time dependence of either the precession or the splitting field the flight-time dispersion of the particles is adequately taken into account. However, until now this quite sophisticated method has not been realized experimentally. We have performed detailed analytical and numerical simulations of such a dynamical polarization facility for pulsed neutron beams in order to proof its feasibility. It turns out that the required space and time dependence of the magnetic fields involved are well within the scope of existing magnet technology. Ref. 1 (author)

  8. Mechanisms of Weight Regain following Weight Loss.

    Science.gov (United States)

    Blomain, Erik Scott; Dirhan, Dara Anne; Valentino, Michael Anthony; Kim, Gilbert Won; Waldman, Scott Arthur

    2013-01-01

    Obesity is a world-wide pandemic and its incidence is on the rise along with associated comorbidities. Currently, there are few effective therapies to combat obesity. The use of lifestyle modification therapy, namely, improvements in diet and exercise, is preferable over bariatric surgery or pharmacotherapy due to surgical risks and issues with drug efficacy and safety. Although they are initially successful in producing weight loss, such lifestyle intervention strategies are generally unsuccessful in achieving long-term weight maintenance, with the vast majority of obese patients regaining their lost weight during followup. Recently, various compensatory mechanisms have been elucidated by which the body may oppose new weight loss, and this compensation may result in weight regain back to the obese baseline. The present review summarizes the available evidence on these compensatory mechanisms, with a focus on weight loss-induced changes in energy expenditure, neuroendocrine pathways, nutrient metabolism, and gut physiology. These findings have added a major focus to the field of antiobesity research. In addition to investigating pathways that induce weight loss, the present work also focuses on pathways that may instead prevent weight regain. Such strategies will be necessary for improving long-term weight loss maintenance and outcomes for patients who struggle with obesity.

  9. Frequency dependence of magnetic ac loss in a Roebel cable made of YBCO on a Ni-W substrate

    Science.gov (United States)

    Lakshmi, L. S.; Staines, M. P.; Badcock, R. A.; Long, N. J.; Majoros, M.; Collings, E. W.; Sumption, M. D.

    2010-08-01

    We have investigated the frequency dependent contributions to the magnetic ac loss in a 10 strand Roebel cable with 2 mm wide non-insulated strands and a transposition length of 90 mm. This cable is made from 40 mm wide YBCO coated conductor tape manufactured by AMSC and stabilized by electroplating 25 µm thick copper on either side prior to the mechanical punching of the cable strands. The measurements were carried out in both perpendicular and parallel field orientation, at frequencies in the range of 30-200 Hz. While the loss in the perpendicular orientation is predominantly hysteretic in nature, we observe some frequency dependence of the loss when the cable approaches full flux penetration at high field amplitudes. The magnitude is consistent with eddy current losses in the copper stabilization layer. This supports the fact that the inter-strand coupling loss is not significant in this frequency range. In the parallel field orientation, the hysteresis loss in the Ni-W alloy substrate dominates, but we see an unusually strong frequency dependent contribution to the loss which we attribute to intra-strand current loops.

  10. Acceptable losses: the debatable origins of loss aversion.

    Science.gov (United States)

    Yechiam, Eldad

    2018-04-16

    It is often claimed that negative events carry a larger weight than positive events. Loss aversion is the manifestation of this argument in monetary outcomes. In this review, we examine early studies of the utility function of gains and losses, and in particular the original evidence for loss aversion reported by Kahneman and Tversky (Econometrica  47:263-291, 1979). We suggest that loss aversion proponents have over-interpreted these findings. Specifically, the early studies of utility functions have shown that while very large losses are overweighted, smaller losses are often not. In addition, the findings of some of these studies have been systematically misrepresented to reflect loss aversion, though they did not find it. These findings shed light both on the inability of modern studies to reproduce loss aversion as well as a second literature arguing strongly for it.

  11. Losses at magnetic nulls in pulsed-power transmission line systems

    International Nuclear Information System (INIS)

    Mendel, C.W. Jr.; Pointon, T.D.; Savage, M.E.; Seidel, D.B.; Magne, I.; Vezinet, R.

    2006-01-01

    Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds

  12. Reducing loss in lateral charged-particle equilibrium due to air cavities present in x-ray irradiated media by using longitudinal magnetic fields

    International Nuclear Information System (INIS)

    Naqvi, Shahid A.; Li, X. Allen; Ramahi, Shada W.; Chu, James C.; Ye, Sung-Joon

    2001-01-01

    The underdosing of lesions distal to air cavities, such as those found in upper respiratory passages, occurs due to the loss in lateral charged-particle equilibrium (CPE). The degree of underdosing worsens for smaller field sizes, resulting in more frequent recurrence of the cancer treated. Higher photon energies further aggravate the outcome by producing longer second build-up regions beyond the cavity. Besides underdosing, the larger lateral spread of secondary electron fluence in the air cavity produces diffuse dose distributions at the tissue-air interface for shaped or intensity modulated fields. These disequilibrium effects create undesirable deviations from the intended treatment. The clinical concern is further intensified by the failure of traditional treatment planning systems to even account for such defects. In this work, the use of longitudinal magnetic fields on the order of 0.5 T is proposed for alleviating lateral electronic disequilibrium due to the presence of air cavities in the irradiated volume. The magnetic field enforces lateral CPE by restricting the lateral range of electrons in the air cavity. The problem is studied in a simple water-air-water slab geometry using EGS4 Monte Carlo simulations for 6 MV photons. Electronic disequilibrium is evaluated for beams of various sizes, shapes and intensity distributions constructed by linear superposition of the dose distributions for 0.5x0.5 cm 2 beamlets. Comparison is also made with 60 Co irradiation. The results indicate that the lateral confinement of secondary electrons in the air cavity by sub-MRI strength longitudinal fields is effective in reducing deterioration of dose distributions near tissue-air interfaces. This can potentially reduce recurrence rates of cancers such as the larynx carcinoma

  13. Scintillator Based Energetic Ion Loss Diagnostic for the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Darrow, D.S.

    2007-01-01

    A scintillator based energetic ion loss detector has been built and installed on the National Spherical Torus Experiment (NSTX) to measure the loss of neutral beam ions. The detector is able to resolve the pitch angle and gyroradius of the lost energetic ions. It has a wide acceptance range in pitch angle and energy, and is able to resolve the full, one-half, and one-third energy components of the 80 keV D neutral beams up to the maximum toroidal magnetic field of NSTX. Multiple Faraday cups have been embedded behind the scintillator to allow easy absolute calibration of the diagnostic and to measure the energetic ion loss to several ranges of pitch angle with good time resolution. Several small, vacuum compatible lamps allow simple calibration of the scintillator position within the field of view of the diagnostic's video camera

  14. Scintillator Based Energetic Ion Loss Diagnostic for the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    D.S. Darrow

    2007-07-02

    A scintillator based energetic ion loss detector has been built and installed on the National Spherical Torus Experiment (NSTX) to measure the loss of neutral beam ions. The detector is able to resolve the pitch angle and gyroradius of the lost energetic ions. It has a wide acceptance range in pitch angle and energy, and is able to resolve the full, one-half, and one-third energy components of the 80 keV D neutral beams up to the maximum toroidal magnetic field of NSTX. Multiple Faraday cups have been embedded behind the scintillator to allow easy absolute calibration of the diagnostic and to measure the energetic ion loss to several ranges of pitch angle with good time resolution. Several small, vacuum compatible lamps allow simple calibration of the scintillator position within the field of view of the diagnostic's video camera.

  15. Fast-ion losses induced by ELMs and externally applied magnetic perturbations in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Garcia-Munoz, M; Rodriguez-Ramos, M; Äkäslompolo, S; De Marne, P; Dunne, M G; Dux, R; Fietz, S; Fuchs, C; Geiger, B; Herrmann, A; Hoelzl, M; Kurzan, B; McDermott, R M; Strumberger, E; Evans, T E; Ferraro, N M; Pace, D C; Lazanyi, N; Nocente, M; Shinohara, K

    2013-01-01

    Phase-space time-resolved measurements of fast-ion losses induced by edge localized modes (ELMs) and ELM mitigation coils have been obtained in the ASDEX Upgrade tokamak by means of multiple fast-ion loss detectors (FILDs). Filament-like bursts of fast-ion losses are measured during ELMs by several FILDs at different toroidal and poloidal positions. Externally applied magnetic perturbations (MPs) have little effect on plasma profiles, including fast-ions, in high collisionality plasmas with mitigated ELMs. A strong impact on plasma density, rotation and fast-ions is observed, however, in low density/collisionality and q 95 plasmas with externally applied MPs. During the mitigation/suppression of type-I ELMs by externally applied MPs, the large fast-ion bursts observed during ELMs are replaced by a steady loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection (NBI) prompt loss signal without MPs. Multiple FILD measurements at different positions, indicate that the fast-ion losses due to static 3D fields are localized on certain parts of the first wall rather than being toroidally/poloidally homogeneously distributed. Measured fast-ion losses show a broad energy and pitch-angle range and are typically on banana orbits that explore the entire pedestal/scrape-off-layer (SOL). Infra-red measurements are used to estimate the heat load associated with the MP-induced fast-ion losses. The heat load on the FILD detector head and surrounding wall can be up to six times higher with MPs than without 3D fields. When 3D fields are applied and density pump-out is observed, an enhancement of the fast-ion content in the plasma is typically measured by fast-ion D-alpha (FIDA) spectroscopy. The lower density during the MP phase also leads to a deeper beam deposition with an inward radial displacement of ≈2 cm in the maximum of the beam emission. Orbit simulations are used to test different models for 3D

  16. Flux loss during the equilibrium phase of field-reversed configurations

    International Nuclear Information System (INIS)

    Tuszewski, M.; Armstrong, W.T.; Bartsch, R.R.; Chrien, R.E.; Cochrane, J.C. Jr.; Kewish, R.W. Jr.; Klingner, P.; Linford, R.K.; McKenna, K.F.; Rej, D.J.; Sherwood, E.G.; Siemon, R.E.

    1982-01-01

    Field-reversed configurations are consistently formed at low filling pressures in the FRX-C device, with decay time of the trapped flux after formation much larger than the stable period. This contrasts with previous experimental observations

  17. Flux loss during the equilibrium phase of field-reversed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Tuszewski, M.; Armstrong, W.T.; Bartsch, R.R.; Chrien, R.E.; Cochrane, J.C. Jr.; Kewish, R.W. Jr.; Klingner, P.; Linford, R.K.; McKenna, K.F.; Rej, D.J.; Sherwood, E.G.; Siemon, R.E.

    1982-10-01

    Field-reversed configurations are consistently formed at low filling pressures in the FRX-C device, with decay time of the trapped flux after formation much larger than the stable period. This contrasts with previous experimental observations.

  18. A numerical method to estimate AC loss in superconducting coated conductors by finite element modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Jiang, Q; Pei, R; Campbell, A M; Coombs, T A [Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2007-04-15

    A finite element method code based on the critical state model is proposed to solve the AC loss problem in YBCO coated conductors. This numerical method is based on a set of partial differential equations (PDEs) in which the magnetic field is used as the state variable. The AC loss problems have been investigated both in self-field condition and external field condition. Two numerical approaches have been introduced: the first model is configured on the cross-section plane of the YBCO tape to simulate an infinitely long superconducting tape. The second model represents the plane of the critical current flowing and is able to simulate the YBCO tape with finite length where the end effect is accounted. An AC loss measurement has been done to verify the numerical results and shows a good agreement with the numerical solution.

  19. My loss is your loss ... Sometimes: loss aversion and the effect of motivational biases.

    Science.gov (United States)

    Wilson, Robyn S; Arvai, Joseph L; Arkes, Hal R

    2008-08-01

    Findings from previous studies of individual decision-making behavior predict that losses will loom larger than gains. It is less clear, however, if this loss aversion applies to the way in which individuals attribute value to the gains and losses of others, or if it is robust across a broad spectrum of policy and management decision contexts. Consistent with previous work, the results from a series of experiments reported here revealed that subjects exhibited loss aversion when evaluating their own financial gains and losses. The presence of loss aversion was also confirmed for the way in which individuals attribute value to the financial gains and losses of others. However, similar evaluations within social and environmental contexts did not exhibit loss aversion. In addition, research subjects expected that individuals who were unknown to them would significantly undervalue the subjects' own losses across all contexts. The implications of these findings for risk-based policy and management are many. Specifically, they warrant caution when relying upon loss aversion to explain or predict the reaction of affected individuals to risk-based decisions that involve moral or protected values. The findings also suggest that motivational biases may lead decisionmakers to assume that their attitudes and beliefs are common among those affected by a decision, while those affected may expect unfamiliar others to be unable to identify and act in accordance with shared values.

  20. Lateralized occipital degeneration in posterior cortical atrophy predicts visual field deficits.

    Science.gov (United States)

    Millington, Rebecca S; James-Galton, Merle; Maia Da Silva, Mari N; Plant, Gordon T; Bridge, Holly

    2017-01-01

    Posterior cortical atrophy (PCA), the visual variant of Alzheimer's disease, leads to high-level visual deficits such as alexia or agnosia. Visual field deficits have also been identified, but often inconsistently reported. Little is known about the pattern of visual field deficits or the underlying cortical changes leading to this visual loss. Multi-modal magnetic resonance imaging was used to investigate differences in gray matter volume, cortical thickness, white matter microstructure and functional activity in patients with PCA compared to age-matched controls. Additional analyses investigated hemispheric asymmetries in these metrics according to the visual field most affected by the disease. Analysis of structural data indicated considerable loss of gray matter in the occipital and parietal cortices, lateralized to the hemisphere contralateral to the visual loss. This lateralized pattern of gray matter loss was also evident in the hippocampus and parahippocampal gyrus. Diffusion-weighted imaging showed considerable effects of PCA on white matter microstructure in the occipital cortex, and in the corpus callosum. The change in white matter was only lateralized in the occipital lobe, however, with greatest change in the optic radiation contralateral to the visual field deficit. Indeed, there was a significant correlation between the laterality of the optic radiation microstructure and visual field loss. Detailed brain imaging shows that the asymmetric visual field deficits in patients with PCA reflect the pattern of degeneration of both white and gray matter in the occipital lobe. Understanding the nature of both visual field deficits and the neurodegenerative brain changes in PCA may improve diagnosis and understanding of this disease.

  1. Compensation of propagation loss of surface plasmon polaritons with a finite-thickness dielectric gain layer

    International Nuclear Information System (INIS)

    Zhang, Xin; Liu, Haitao; Zhong, Ying

    2012-01-01

    We theoretically study the compensation of propagation loss of surface plasmon polaritons (SPPs) with the use of a finite-thickness dielectric layer with optical gain. The impacts of the gain coefficient, the gain-layer thickness and the wavelength on the loss compensation and the field distribution of the SPP mode are systematically explored with a fully vectorial method. Abnormal behaviors for the loss compensation as the gain-layer thickness increases are found and explained. Critical values of the gain coefficient and of the corresponding gain-layer thickness for just compensating the propagation loss are provided. Our results show that as the SPP propagation loss is fully compensated with a gain coefficient at a reasonably low level, the gain layer is still thin enough to ensure a large exterior SPP field at the gain-layer/air interface, which is important for achieving a strong light–matter interaction for applications such as bio-chemical sensing. (paper)

  2. Rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation

    Energy Technology Data Exchange (ETDEWEB)

    Teshima, Hidekazu [Nippon Steel Corp., Kawasaki, Kanagawa (Japan). Advanced Materials and Technology Research Labs.; Tawara, Taichi; Shimada, Ryuichi

    1997-08-01

    This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

  3. Round window stimulation for conductive and mixed hearing loss.

    Science.gov (United States)

    Dillon, Margaret T; Tubbs, Rhonda S; Adunka, Marcia C; King, English R; Hillman, Todd A; Adunka, Oliver F; Chen, Douglas A; Buchman, Craig A

    2014-10-01

    Assess surgical complications, postoperative residual hearing, and speech perception outcomes of placement of a middle ear implant on the round window in conductive and mixed hearing loss cases. Single-subject, repeated-measures design where each subject served as his or her own control. Tertiary referral medical systems. Eighteen subjects with either conductive or mixed hearing loss who could not benefit from conventional amplification were enrolled in a clinical trial investigating vibratory stimulation of the round window. The floating mass transducer (FMT) was positioned in the round window niche. Unaided residual hearing, and aided sound field thresholds and speech perception abilities were evaluated preoperatively, and at 1, 3, 6, and 10 months post-activation of the external speech processor. Six subjects experienced complications that either required further medical management or resolved on their own. There was no difference in residual bone conduction thresholds or unaided word discrimination over time. All subjects experienced a significant improvement in aided speech perception abilities as compared to preoperative performance. Subjects with conductive and mixed hearing loss with placement of the FMT in the round window niche experienced improved sound field thresholds and speech perception, without compromising residual hearing thresholds. Vibratory stimulation of the round window via a middle ear implant may be an appropriate treatment option for patients with conductive and mixed hearing loss. Additional research is needed on the preferred placement of the FMT, improvement of functional gain, and methods to limit postoperative complications and need for revision surgery.

  4. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.

    2013-01-01

    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

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

    International Nuclear Information System (INIS)

    Murakami, Masafumi; Kobari, Hitomi; Kanno, Hidetaka; Aikawa, Tohru; Anzai, Tomohiro; Okamura, Hiro-oki; Ohtani, Iwao; Hoshino, Toshiaki

    1989-01-01

    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)

  6. Relationship among visual field, blood flow, and neural structure measurements in glaucoma.

    Science.gov (United States)

    Hwang, John C; Konduru, Ranjith; Zhang, Xinbo; Tan, Ou; Francis, Brian A; Varma, Rohit; Sehi, Mitra; Greenfield, David S; Sadda, Srinivas R; Huang, David

    2012-05-17

    To determine the relationship among visual field, neural structural, and blood flow measurements in glaucoma. Case-control study. Forty-seven eyes of 42 patients with perimetric glaucoma were age-matched with 27 normal eyes of 27 patients. All patients underwent Doppler Fourier-domain optical coherence tomography to measure retinal blood flow and standard glaucoma evaluation with visual field testing and quantitative structural imaging. Linear regression analysis was performed to analyze the relationship among visual field, blood flow, and structure, after all variables were converted to logarithmic decibel scale. Retinal blood flow was reduced in glaucoma eyes compared to normal eyes (P flow and structural loss of rim area and retinal nerve fiber layer (RNFL). There was no correlation or paradoxical correlation between blood flow and structure. Multivariate regression analysis revealed that reduced blood flow and structural loss are independent predictors of visual field loss. Each dB decrease in blood flow was associated with at least 1.62 dB loss in mean deviation (P ≤ 0.001), whereas each dB decrease in rim area and RNFL was associated with 1.15 dB and 2.56 dB loss in mean deviation, respectively (P ≤ 0.03). There is a close link between reduced retinal blood flow and visual field loss in glaucoma that is largely independent of structural loss. Further studies are needed to elucidate the causes of the vascular dysfunction and potential avenues for therapeutic intervention. Blood flow measurement may be useful as an independent assessment of glaucoma severity.

  7. Hearing loss

    Science.gov (United States)

    Decreased hearing; Deafness; Loss of hearing; Conductive hearing loss; Sensorineural hearing loss; Presbycusis ... Symptoms of hearing loss may include: Certain sounds seeming too loud Difficulty following conversations when two or more people are talking ...

  8. Colorado Ultraviolet Transit Experiment: a dedicated CubeSat mission to study exoplanetary mass loss and magnetic fields

    Science.gov (United States)

    Fleming, Brian T.; France, Kevin; Nell, Nicholas; Kohnert, Richard; Pool, Kelsey; Egan, Arika; Fossati, Luca; Koskinen, Tommi; Vidotto, Aline A.; Hoadley, Keri; Desert, Jean-Michel; Beasley, Matthew; Petit, Pascal M.

    2018-01-01

    The Colorado Ultraviolet Transit Experiment (CUTE) is a near-UV (2550 to 3300 Å) 6U CubeSat mission designed to monitor transiting hot Jupiters to quantify their atmospheric mass loss and magnetic fields. CUTE will probe both atomic (Mg and Fe) and molecular (OH) lines for evidence of enhanced transit absorption, and to search for evidence of early ingress due to bow shocks ahead of the planet's orbital motion. As a dedicated mission, CUTE will observe ≳100 spectroscopic transits of hot Jupiters over a nominal 7-month mission. This represents the equivalent of >700 orbits of the only other instrument capable of these measurements, the Hubble Space Telescope. CUTE efficiently utilizes the available CubeSat volume by means of an innovative optical design to achieve a projected effective area of ˜28 cm2, low instrumental background, and a spectral resolving power of R˜3000 over the primary science bandpass. These performance characteristics enable CUTE to discern transit depths between 0.1% and 1% in individual spectral absorption lines. We present the CUTE optical and mechanical design, a summary of the science motivation and expected results, and an overview of the projected fabrication, calibration, and launch timeline.

  9. A Small Disc Area Is a Risk Factor for Visual Field Loss Progression in Primary Open-Angle Glaucoma: The Glaucoma Stereo Analysis Study

    Directory of Open Access Journals (Sweden)

    Yasushi Kitaoka

    2018-01-01

    Full Text Available Purpose. The Glaucoma Stereo Analysis Study, a cross-sectional multicenter collaborative study, used a stereo fundus camera (nonmyd WX to assess various morphological parameters of the optic nerve head (ONH in glaucoma patients. We compared the associations of each parameter between the visual field loss progression group and no-progression group. Methods. The study included 187 eyes of 187 patients with primary open-angle glaucoma or normal-tension glaucoma. We divided the mean deviation (MD slope values of all patients into the progression group (<−0.3 dB/year and no-progression group (≧−0.3 dB/year. ONH morphological parameters were calculated with prototype analysis software. The correlations between glaucomatous visual field progression and patient characteristics or each ONH parameter were analyzed with Spearman’s rank correlation coefficient. Results. The MD slope averages in the progression group and no-progression group were −0.58 ± 0.28 dB/year and 0.05 ± 0.26 dB/year, respectively. Among disc parameters, vertical disc width (diameter, disc area, cup area, and cup volume in the progression group were significantly less than those in the no-progression group. Logistic regression analysis revealed a significant association between the visual field progression and disc area (odds ratio 0.49/mm2 disc area. Conclusion. A smaller disc area may be associated with more rapid glaucomatous visual field progression.

  10. Context dependency and saturating effects of loss of rare soil microbes on plant productivity

    Directory of Open Access Journals (Sweden)

    Gera eHol

    2015-06-01

    Full Text Available Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing towards a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  11. Context dependency and saturating effects of loss of rare soil microbes on plant productivity.

    Science.gov (United States)

    Hol, W H Gera; de Boer, Wietse; de Hollander, Mattias; Kuramae, Eiko E; Meisner, Annelein; van der Putten, Wim H

    2015-01-01

    Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition, and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing toward a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  12. Analysis of fast losses in the LHC with the BLM system

    CERN Document Server

    Nebot, E; Holzer, E; Dehning, B; Nordt, A; Sapinski, M; Emery, J; Zamantzas, C; Effinger, E; Marsili, A; Wenninger, J; Baer, T; Schmidt, R; Yang, Z; Zimmerman, F; Fuster, N

    2011-01-01

    About 3600 Ionization Chambers are located around the LHC ring to detect beam losses that could damage the equipment or quench superconducting magnets. The Beam Loss Monitors (BLMs) integrate the losses in 12 different time intervals (from 40 us to 83.8 s) allowing for different abort thresholds depending on the duration of the loss and the beam energy. The signals are also recorded in a database at 1 Hz for offline analysis. During the 2010 run, a limiting factor in the machine availability were sudden losses appearing around the ring on the ms time scale and detected exclusively by the BLM system. It is believed that such losses originate from dust particles falling into the beam, or being attracted by its strong electromagnetic field. This document describes some of the properties of these ”Unidentified Falling Objects” (UFOs) putting special emphasis on their dependence on beam parameters (energy, intensity, etc). The subsequent modification of the BLM beam abort thresholds for the 2011 run that were ...

  13. Dexamethasone Implant (Ozurdex in a Case with Unilateral Simultaneous Central Retinal Vein and Branch Retinal Artery Occlusion

    Directory of Open Access Journals (Sweden)

    Taylan Ozturk

    2015-02-01

    Full Text Available Simultaneous branch retinal artery and vein occlusion is a rare condition that may cause severe visual loss, and its treatment is often unrewarding. Herein, we report a case with simultaneous central retinal vein and branch retinal artery occlusion; it was successfully treated with a single dexamethasone intravitreal implant. The affected eye attained a visual acuity level of 20/25 from the visual acuity of hand motions at presentation with a residual, but relatively diminished, altitudinal scotoma during a follow-up period of 6 months.

  14. Energy losses (gains) of massive coloured particles in stochastic colour medium

    International Nuclear Information System (INIS)

    Leonidov, A.; Rossijskaya Akademiya Nauk, Moscow

    1995-01-01

    The propagation of massive coloured particles in stochastic background chromoelectric field is studied using the semiclassical equations of motion. Depending on the nature of the stochastic background we obtain the formulae for the energy losses of heavy coloured projectile in nonperturbative hadronic medium and for the energy gains in the stochastic field present, e.g., in the turbulent plasma. The result appears to be significantly dependent on the form of the correlation function of stochastic external field. (orig.)

  15. Influence of Inter-Intra Row Spacing on Yield Losses of Tomato ...

    African Journals Online (AJOL)

    losses of tomato growing under open field production with fresh market (Bishola) and processing ..... AVRDC. 2003. Asian Vegetable Research and Development Centre, Shanhua, Tainan, progress ... Australia national universities. 20: 1.

  16. Vivid valleys, pallid peaks? Hypsometric variations and rural-urban land change in the Central Peruvian Andes.

    Science.gov (United States)

    Haller, Andreas

    2012-11-01

    What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano - an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor ( quechua ) - since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes ( suni ) and subsequent grassland ecosystems ( puna ), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes - despite rural-urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural-urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use - at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps - from the bottom up.

  17. Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna.

    Science.gov (United States)

    Malatesta, Luca; Tardella, Federico Maria; Piermarteri, Karina; Catorci, Andrea

    2016-01-01

    Facilitation processes constitute basic elements of vegetation dynamics in harsh systems. Recent studies in tropical alpine environments demonstrated how pioneer plant species defined as "ecosystem engineers" are capable of enhancing landscape-level richness by adding new species to the community through the modification of microhabitats, and also provided hints about the alternation of different ecosystem engineers over time. Nevertheless, most of the existing works analysed different ecosystem engineers separately, without considering the interaction of different ecosystem engineers. Focusing on the altitudinal limit of Peruvian Dry Puna vegetation, we hypothesized that positive interactions structure plant communities by facilitation cascades involving different ecosystem engineers, determining the evolution of the microhabitat patches in terms of abiotic resources and beneficiary species hosted. To analyze successional mechanisms, we used a "space-for-time" substitution to account for changes over time, and analyzed data on soil texture, composition, and temperature, facilitated species and their interaction with nurse species, and surface area of engineered patches by means of chemical analyses, indicator species analysis, and rarefaction curves. A successional process, resulting from the dynamic interaction of different ecosystem engineers, which determined a progressive amelioration of soil conditions (e.g. nitrogen and organic matter content, and temperature), was the main driver of species assemblage at the community scale, enhancing species richness. Cushion plants act as pioneers, by starting the successional processes that continue with shrubs and tussocks. Tussock grasses have sometimes been found to be capable of creating microhabitat patches independently. The dynamics of species assemblage seem to follow the nested assemblage mechanism, in which the first foundation species to colonize a habitat provides a novel substrate for colonization by other

  18. Ions extraction and collection using the RF resonance method and taking into consideration the sputtering loss

    International Nuclear Information System (INIS)

    Xie Guofeng; Wang Dewu; Ying Chuntong

    2005-01-01

    One-dimensional ions extraction and collection using the RF resonance method is studied by PIC-MCC simulation. The energy and angle distribution of extracted ions is recorded and the sputtering loss is calculated. The results show that compared with parallel electrode method, RF resonance method has advantages such as shorter extraction time, lower collision loss and sputtering loss and higher collection ratio; the extraction time and collision loss are decreased with increasing extraction voltage, but the sputtering loss increases and collection ratio decreases; collision loss is decreased with increasing magnetic field, but the sputtering loss increases and collection ratio decreases. (authors)

  19. A. C. losses in current-carrying superconductors

    Energy Technology Data Exchange (ETDEWEB)

    De Reuver, J L

    1985-01-01

    After a description of some basic concepts of superconductivity and the applied wire types, the basic measuring technique is dealt with. The performed measurements are given. The modification of the measuring technique will be explained. The prior interest is the theoretical description and the agreement between theory and experiment. Attention to various external field conditions is given, and to the self-field instability. Apart from theoretical considerations, measurements have been performed on types of wire which are less conventional. The intention is to contribute to the search for a type of wire with both low losses and a good stabilization under self-field conditions. The evaluation and conclusions concentrate on the developed measuring techniques, significant contributions to the theoretical verification and the proposed alternative wire configuration. (J.C.R.)

  20. Fine-grained entanglement loss along renormalization-group flows

    International Nuclear Information System (INIS)

    Latorre, J.I.; Rico, E.; Luetken, C.A.; Vidal, G.

    2005-01-01

    We explore entanglement loss along renormalization group trajectories as a basic quantum information property underlying their irreversibility. This analysis is carried out for the quantum Ising chain as a transverse magnetic field is changed. We consider the ground-state entanglement between a large block of spins and the rest of the chain. Entanglement loss is seen to follow from a rigid reordering, satisfying the majorization relation, of the eigenvalues of the reduced density matrix for the spin block. More generally, our results indicate that it may be possible to prove the irreversibility along renormalization group trajectories from the properties of the vacuum only, without need to study the whole Hamiltonian

  1. Environmental Profile of the Swiss Supply Chain for French Fries: Effects of Food Loss Reduction, Loss Treatments and Process Modifications

    Directory of Open Access Journals (Sweden)

    Patrik Mouron

    2016-11-01

    Full Text Available The production of food is responsible for major environmental impacts. Bearing this in mind, it is even worse when food is lost rather than consumed. In Switzerland, 46% of all processing potatoes and 53% of all fresh potatoes are lost on their way from field to fork. Our study therefore compares the environmental impacts of losses of fresh potatoes with those of French fries. With the aid of a Life Cycle Assessment, we assessed the impact categories “demand for nonrenewable energy resources”, “global warming potential”, “human toxicity”, “terrestrial ecotoxicity” and “aquatic ecotoxicity”. Our results show that 1 kg of potatoes consumed as French fries causes 3–5 times more environmental impacts than the same quantity of fresh potatoes, but also that the proportion of impacts relating to losses is considerably lower for French fries (5%–10% vs. 23%–39%. The great majority of processing potato losses occur before the resource-intensive, emission-rich frying processes and therefore the environmental “backpack” carried by each lost potato is still relatively small. Nonetheless, appropriate loss treatment can substantially reduce the environmental impact of potato losses. In the case of French fries, the frying processes and frying oil are the main “hot spots” of environmental impacts, accounting for a considerably higher proportion of damage than potato losses; it is therefore also useful to look at these processes.

  2. Antigen Loss Variants: Catching Hold of Escaping Foes.

    Science.gov (United States)

    Vyas, Maulik; Müller, Rolf; Pogge von Strandmann, Elke

    2017-01-01

    Since mid-1990s, the field of cancer immunotherapy has seen steady growth and selected immunotherapies are now a routine and preferred therapeutic option of certain malignancies. Both active and passive cancer immunotherapies exploit the fact that tumor cells express specific antigens on the cell surface, thereby mounting an immune response specifically against malignant cells. It is well established that cancer cells typically lose surface antigens following natural or therapy-induced selective pressure and these antigen-loss variants are often the population that causes therapy-resistant relapse. CD19 and CD20 antigen loss in acute lymphocytic leukemia and chronic lymphocytic leukemia, respectively, and lineage switching in leukemia associated with mixed lineage leukemia (MLL) gene rearrangements are well-documented evidences in this regard. Although increasing number of novel immunotherapies are being developed, majority of these do not address the control of antigen loss variants. Here, we review the occurrence of antigen loss variants in leukemia and discuss the therapeutic strategies to tackle the same. We also present an approach of dual-targeting immunoligand effectively retargeting NK cells against antigen loss variants in MLL-associated leukemia. Novel immunotherapies simultaneously targeting more than one tumor antigen certainly hold promise to completely eradicate tumor and prevent therapy-resistant relapses.

  3. Theoretical analysis on ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

    CERN Document Server

    Iwakuma, M; Funaki, K

    2002-01-01

    The ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands were theoretically investigated. The constituent strands generally need to be insulated and transposed for the sake of uniform current distribution and low ac loss. In case the transposition points deviate from the optimum ones, shielding current is induced according to the interlinkage magnetic flux of the twisted loop enclosed by the insulated strands and the contact resistances at the terminals. It produces an additional ac loss. Supposing a simple situation where a two-strand parallel conductor with one-point transposition is exposed to a uniform ac magnetic field, the basic equations for the magnetic field were proposed and the theoretical expressions of the additional ac losses derived. As a result, the following features were shown. The additional ac loss in the non-saturation case, where the induced shielding current is less than the critical current of a strand, is proportional to the square ...

  4. Comparison of self-field effects between Bi-2223/Ag tapes and pancake coils

    International Nuclear Information System (INIS)

    Alamgir, A.K.M.; Gu, C.; Han, Z.

    2005-01-01

    Knowledge on self-field behavior in HTS tape and coil becomes important for the design of HTS devices. We report on the comparative nature and influence of self-field in Bi-2223/Ag tape and pancake coils in terms of critical current and ac loss. Measured dc and ac properties of short tape and pancake coils are verified based on the self-field. It is proved that perpendicular component of self-field acting in opposite direction at the two halves of tape-width determines critical current in short tape and single-turn coil. On the other hand, perpendicular component of self-field pointed in the same direction at the two halves of tape-width determines critical current in multi-turn coils. Influence of magnitude and orientation of self-field on ac loss is also investigated for a series of pancake coils based on the measured self-field ac loss in short sample

  5. Comparison of self-field effects between Bi-2223/Ag tapes and pancake coils

    Energy Technology Data Exchange (ETDEWEB)

    Alamgir, A.K.M. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Building Li Zhai, Room 209, Beijing 100084 (China)]. E-mail: alam643@yahoo.com; Gu, C. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Building Li Zhai, Room 209, Beijing 100084 (China); Han, Z. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Building Li Zhai, Room 209, Beijing 100084 (China)

    2005-08-15

    Knowledge on self-field behavior in HTS tape and coil becomes important for the design of HTS devices. We report on the comparative nature and influence of self-field in Bi-2223/Ag tape and pancake coils in terms of critical current and ac loss. Measured dc and ac properties of short tape and pancake coils are verified based on the self-field. It is proved that perpendicular component of self-field acting in opposite direction at the two halves of tape-width determines critical current in short tape and single-turn coil. On the other hand, perpendicular component of self-field pointed in the same direction at the two halves of tape-width determines critical current in multi-turn coils. Influence of magnitude and orientation of self-field on ac loss is also investigated for a series of pancake coils based on the measured self-field ac loss in short sample.

  6. Coil geometry models for power loss analysis and hybrid inductive ...

    Indian Academy of Sciences (India)

    CHANDRASEKHARAN NATARAJ

    2018-04-26

    Apr 26, 2018 ... most of the WPT systems, but often suffers from power loss in the near field area of inductively coupled ... applications in the area of Distribution Generation (DG) ... embedded sensors, and buried devices, work at low voltage.

  7. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    Science.gov (United States)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza

    2008-01-01

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency.

  8. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    International Nuclear Information System (INIS)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza

    2008-01-01

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency

  9. A new approach for AC loss reduction in HTS transformer using auxiliary windings, case study: 25 kA HTS current injection transformer

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, Hossein; Faghihi, Faramarz; Aligholizadeh, Reza [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2008-01-15

    AC loss is one of the important parameters in HTS (high temperature superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in the electrical power system. The AC losses in an HTS tape depend on the magnetic field. One of the techniques usually adopted to mitigate the unwanted magnetic field is using a system of coils that produce a magnetic field opposite to the incident one, reducing the total magnetic field. In this paper adding two auxiliary windings to the HTS transformer to produce this opposite magnetic field is proposed. The proper use of these auxiliary windings could reduce the leakage flux and, therefore, the AC loss. A mathematical model is used to describe the behaviour of a transformer operating with auxiliary windings, based on the theory of electromagnetic coupled circuits. The influence of the auxiliary windings on the leakage field is studied by the finite element method (FEM) and the AC loss of an HTS transformer was calculated. Also, the simulation results show that employing auxiliary windings will improve the HTS transformer efficiency.

  10. Hot spot model of MagLIF implosions: Nernst term effect on magnetic flux losses

    Science.gov (United States)

    Garcia Rubio, Fernando; Sanz Recio, Javier; Betti, Riccardo

    2016-10-01

    An analytical model of a collisional plasma being compressed by a cylindrical liner is proposed and solved in a magnetized liner inertial fusion-like context. The implosion is assumed to be isobaric, and the magnetic diffusion is confined to a thin layer near the liner. Both unmagnetized and magnetized plasma cases are considered. The model reduces to a system of two partial differential equations for temperature and magnetic field. Special attention is given to the effect of the Nernst term on the evolution of the magnetic field. Scaling laws for temperature, magnetic field, hot spot mass increase and magnetic field losses are obtained. The temperature and magnetic field spatial profiles tend to a self-similar state. It is found that when the Nernst term is taken into account, the magnetic field is advected towards the liner, and the magnetic flux losses are independent of the magnetic Lewis number. Research supported by the Spanish Ministerio de Economía y Competitividad, Project No. ENE2014-54960R. Acknowledgements to the Laboratory of Laser Energetics (Rochester) for its hospitality.

  11. Fast-ion losses induced by ACs and TAEs in the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    GarcIa-Munoz, M.; Hicks, N.; Classen, I.G.J.; Bilato, R.; Bobkov, V.; Brambilla, M.; Bruedgam, M.; Fahrbach, H.-U.; Igochine, V.; Maraschek, M.; Sassenberg, K.; Van Voornveld, R.; Jaemsae, S.

    2010-01-01

    The phase-space of convective and diffusive fast-ion losses induced by shear Alfven eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfven eigenmodes (TAEs) and Alfven cascades (ACs) have allowed to identify both loss mechanisms. While single ACs and TAEs eject resonant fast-ions in a convective process, the overlapping of AC and TAE spatial structures leads to a large fast-ion diffusion and loss. The threshold for diffusive fast-ion losses depends on the ion energy (gyroradius). Diffusive fast-ion losses with gyroradius ∼70 mm have been observed with a single TAE for local radial displacements of the magnetic field lines larger than ∼2 mm. Multiple frequency chirping ACs cause an enhancement of the diffusive losses. The ACs and TAEs radial structures have been reconstructed by means of cross-correlation techniques between the fast-ion loss detector and the electron cyclotron emission radiometer.

  12. Analysing changes in land cover in relation to environmental factors in the districts of Znojmo and Třebíč (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Brovkina, Olga; Zemek, František; Novotný, Jan; Heřman, Michal; Štěpánek, Petr

    2017-01-01

    Roč. 7, č. 2 (2017), s. 108-118 ISSN 1805-0174 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : object-based classification * driving forces * landscape * china * mountains * patterns * pyrenees * science * land use * satellite data * climatic parameters * altitudinal gradient * slope of terrain * field size Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7)

  13. Respiration rate of stream insects measured in situ along a large altitude range

    DEFF Research Database (Denmark)

    Rostgaard, S.; Jacobsen, D.

    2005-01-01

    Field studies of respiration in stream insects are few in comparison with laboratory studies. To evaluate the influence of temperature and oxygen along altitudinal gradients we measured the respiration rate of fully acclimatized larval Trichoptera, Plecoptera and Ephemeroptera under similar field...... at 100 and 50% oxygen saturation indicated that highland animals reduced their oxygen uptake more than their counterparts in the lowland when oxygen availability decreased. The temperature response of respiration calculated between the insect assemblages at different altitudes showed a mean assemblage Q...

  14. Simultaneous measurements of ion and electron currents using a novel compact electrostatic end-loss-current detector

    Science.gov (United States)

    Hirata, M.; Miyake, Y.; Cho, T.; Kohagura, J.; Numakura, T.; Shimizu, K.; Ito, M.; Kiminami, S.; Morimoto, N.; Hirai, K.; Yamagishi, T.; Miyata, Y.; Nakashima, Y.; Miyoshi, S.; Ogura, K.; Kondoh, T.; Kariya, T.

    2006-10-01

    For the purpose of end-loss-ion and -electron analyses in open-field plasmas, a compact-sized electrostatic end-loss-current detector is proposed on the basis of a self-collection principle for suppressing the effects of secondary-electron emission from a metal collector. For employing this specific method, it is worth noting that no further additional magnetic systems except the ambient open-ended magnetic fields are required in the detector operation. This characteristic property provides a compactness of the total detection system and availability for its use in plasma confinement devices without disturbing plasma-confining magnetic fields. The detector consists of a set of parallel metal plates with respect to lines of ambient magnetic forces of a plasma device for analyzing incident ion currents along with a grid for shielding the collector against strays due to the metal-plate biasing. The characterization experiments are carried out by the use of a test-ion-beam line along with an additional use of a Helmholtz coil system for the formation of open magnetic fields similar to those in the GAMMA 10 end region. The applications of the developed end-loss-current detector in the GAMMA 10 plasma experiments are demonstrated under the conditions with simultaneous incidence of energetic electrons produced by electron-cyclotron heatings for end-loss-plugging potential formation.

  15. The Effect of the Feedback Controller on Superconducting Tokamak AC Losses + AC-CRPP user manual

    International Nuclear Information System (INIS)

    Schaerz, B.; Bruzzone, P.; Favez, J.Y.; Lister, J.B.; Zapretilina, E.

    2001-11-01

    Superconducting coils in a Tokamak are subject to AC losses when the field transverse to the coil current varies. A simple model to evaluate the AC losses has been derived and benchmarked against a complete model used in the ITER design procedure. The influence of the feedback control strategy on the AC losses is examined using this model. An improved controller is proposed, based on this study. (author)

  16. Pregnancy Loss

    Science.gov (United States)

    ... To receive Pregnancy email updates Enter email Submit Pregnancy loss Pregnancy loss is a harsh reality faced ... have successful pregnancies. Expand all | Collapse all Why pregnancy loss happens As many as 10 to 15 ...

  17. Tight-binding calculation of radiation loss in photonic crystal CROW.

    Science.gov (United States)

    Ma, Jing; Martínez, Luis Javier; Fan, Shanhui; Povinelli, Michelle L

    2013-01-28

    The tight binding approximation (TBA) is used to relate the intrinsic, radiation loss of a coupled resonator optical waveguide (CROW) to that of a single constituent resonator within a light cone picture. We verify the validity of the TBA via direct, full-field simulation of CROWs based on the L2 photonic crystal cavity. The TBA predicts that the quality factor of the CROW increases with that of the isolated cavity. Moreover, our results provide a method to design CROWs with low intrinsic loss across the entire waveguide band.

  18. Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1979-September 30, 1980

    International Nuclear Information System (INIS)

    York, T.M.; Klevans, E.H.

    1980-05-01

    Experimental and analytical studies of particle and energy loss at the ends of a linear theta pinch have been carried out. A study of transients occurring in the formation of reversed trapped fields within the coil, and of transients in the end region of a 25 cm long device was completed. A 1-D code has proven to be highly accurate in describing loss events and defining transport mechanisms in different experiments and is described here. A study of loss along field lines in a 50 cm long device has generated new information on loss velocity, axial and radial temperature gradients, and has established an initial effort in understanding thermal loss to the walls. Rotation and parallel trapped fields have been added to the existing 0-D code. A new technique crowbar switch and magnetic field prediction code have been developed. Direct measurment of electron velocity with Thomson scattering was accomplished experimentally. A Nd-glass laser system, frequency doubled, is being developed for low density diagnostics. Theoretical results that accurately predict confinement in FRX devices are described

  19. Comparative Studies on the Bioretention of Radionuclides under Laboratory and Field Conditions

    International Nuclear Information System (INIS)

    Heyraud, M.; Fowler, S.W.

    1976-01-01

    The influence of different sea water treatments on radio-isotope flux rates was tested in three species. For any one species no significant differences in 65 Zn loss rate were noted between organisms held in sea water collected in situ and in those maintained in sea water from the laboratory system. Increased sea water zinc concentration accelerated 65 Zn flux rates; however, the more rapid 65 Zn loss compared to that measured in control sea water was only significant when the concentration was increased by 100μg zinc/liter. Simultaneous laboratory and field experiments indicated that loss rates in clams and mussels were similar whether animals were held in the field or in the laboratory. Experiments in which crabs were monitored for 65 Zn loss gave conflicting results. One experiment performed during the summer indicated that crabs lost 65 Zn significantly faster in the laboratory than in the field. Another experiment performed during the winter when water temperatures were lower indicated no differences in loss rates between the two systems. Differences in radioisotope flux rate may have been related to the intermolt cycle; nevertheless, it was concluded that for certain organisms care should be exercised when applying results of laboratory experiments to the field situation. (author)

  20. Prediction of flux loss in a Nd-Fe-B ring magnet considering magnetizing process

    International Nuclear Information System (INIS)

    Fukunaga, H; Koreeda, H; Yanai, T; Nakano, M; Yamashita, F

    2010-01-01

    We developed a technique to predict flux loss of a magnet with a complicated magnetization pattern using the finite element method. The developed method consists of four steps. At first, the distribution of magnetization under magnetizing field is analyzed (Step 1), and a demagnetization curve of each element is deduced from the result of the first step (Step 2). After removing the magnetizing field, the distributions of magnetization at room and elevated temperatures are analyzed by using demagnetization curves determined in Step 2 (Step 3). Based on a physical model, the distribution of flux loss due to exposure at the elevated temperature is predicted by using the result obtained in Step 3 (Step 4). We applied this technique to a ring magnet with 10 poles, and large flux loss values were predicted at the transition regions between magnetic poles.

  1. Toroidal field ripple effects in large tokamaks

    International Nuclear Information System (INIS)

    Uckan, N.A.; Tsang, K.T.; Callen, J.D.

    1975-01-01

    In an experimental power reactor, the ripple produced by the finite number of toroidal field coils destroys the ideal axisymmetry of the configuration and is responsible for additional particle trapping, loss regions and plasma transport. The effects of toroidal field ripple on the plasma transport coefficient, the loss of alpha particles and energetic injection ions, and the relaxation of toroidal flows are investigated in a new and systematic way. The relevant results are applied to the ORNL-EPR reference design; the maximum ripple there of about 2.2 percent at the outer edge of the plasma column is found to be tolerable from plasma physics considerations

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

    Science.gov (United States)

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

    2015-06-23

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

  3. A quick earthquake disaster loss assessment method supported by dasymetric data for emergency response in China

    Science.gov (United States)

    Xu, Jinghai; An, Jiwen; Nie, Gaozong

    2016-04-01

    Improving earthquake disaster loss estimation speed and accuracy is one of the key factors in effective earthquake response and rescue. The presentation of exposure data by applying a dasymetric map approach has good potential for addressing this issue. With the support of 30'' × 30'' areal exposure data (population and building data in China), this paper presents a new earthquake disaster loss estimation method for emergency response situations. This method has two phases: a pre-earthquake phase and a co-earthquake phase. In the pre-earthquake phase, we pre-calculate the earthquake loss related to different seismic intensities and store them in a 30'' × 30'' grid format, which has several stages: determining the earthquake loss calculation factor, gridding damage probability matrices, calculating building damage and calculating human losses. Then, in the co-earthquake phase, there are two stages of estimating loss: generating a theoretical isoseismal map to depict the spatial distribution of the seismic intensity field; then, using the seismic intensity field to extract statistics of losses from the pre-calculated estimation data. Thus, the final loss estimation results are obtained. The method is validated by four actual earthquakes that occurred in China. The method not only significantly improves the speed and accuracy of loss estimation but also provides the spatial distribution of the losses, which will be effective in aiding earthquake emergency response and rescue. Additionally, related pre-calculated earthquake loss estimation data in China could serve to provide disaster risk analysis before earthquakes occur. Currently, the pre-calculated loss estimation data and the two-phase estimation method are used by the China Earthquake Administration.

  4. Pathogenesis of age-related bone loss in humans.

    Science.gov (United States)

    Khosla, Sundeep

    2013-10-01

    Although data from rodent systems are extremely useful in providing insights into possible mechanisms of age-related bone loss, concepts evolving from animal models need to ultimately be tested in humans. This review provides an update on mechanisms of age-related bone loss in humans based on the author's knowledge of the field and focused literature reviews. Novel imaging, experimental models, biomarkers, and analytic techniques applied directly to human studies are providing new insights into the patterns of bone mass acquisition and loss as well as the role of sex steroids, in particular estrogen, on bone metabolism and bone loss with aging in women and men. These studies have identified the onset of trabecular bone loss at multiple sites that begins in young adulthood and remains unexplained, at least based on current paradigms of the mechanisms of bone loss. In addition, estrogen appears to be a major regulator of bone metabolism not only in women but also in men. Studies assessing mechanisms of estrogen action on bone in humans have identified effects of estrogen on RANKL expression by several different cell types in the bone microenvironment, a role for TNF-α and IL-1β in mediating effects of estrogen deficiency on bone, and possible regulation of the Wnt inhibitor, sclerostin, by estrogen. There have been considerable advances in our understanding of age-related bone loss in humans. However, there are also significant gaps in knowledge, particularly in defining cell autonomous changes in bone in human studies to test or validate concepts emerg