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Sample records for altitudinal field loss

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

    Directory of Open Access Journals (Sweden)

    Chen Celia S

    2010-03-01

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

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

    Science.gov (United States)

    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. Low vision rehabilitation for a target-shooting marksman with visual field loss and diplopia.

    Science.gov (United States)

    Jamara, Richard; Potaznick, Walter; Matjucha, Ippolit

    2008-05-01

    In the United States in 2006, there were 17.8 million hunters and 17.1 million target shooters. When these sportsmen suffer significant visual loss, it can have a devastating effect on their participation in the shooting sports. According to the National Rifle Association, there are no reliable data sources on the number of target shooters with visual impairment. This case report describes a retired, nationally ranked, competitive target shooter who suffered bilateral visual field loss secondary to nonarteritic anterior ischemic optic neuropathy and diplopia secondary to cerebral vascular accident. A retired 67-year-old white man was referred by a local optometrist to a neuro-ophthalmologist with a suspicious finding of disc pallor and a restriction of the visual field. Examination revealed right hypertropia and visual field defects: binocular superior altitudinal losses and inferior arcuate loss in his dominant, right eye. He had best-corrected distance acuity of 20/20 - 2 in the right eye and 20/25 - 2 in the left eye. Because of this, he received several adaptive rehabilitation devices to help him regain his shooting performance. These included a single-vision add for the pistol sight, yellow tint, low-power telescope, and patching. In this report, the fundamentals of eye care for competitive shooting are described with an emphasis on providing the best acuity for presbyopic patient prescriptions at nonstandard distances and the avoidance of diplopia. A visually impaired sportsman who participated in shooting sports at a high level was attempting to return to his previous shooting performance. This case report shows how sports vision and low vision rehabilitation techniques can improve the visual function of a competitive shooter.

  4. 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

  5. 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

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

    NARCIS (Netherlands)

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

    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

  7. Self-field loss of BSCCOrAg tape in external AC magnetic field

    NARCIS (Netherlands)

    Rabbers, J.J.; ten Haken, Bernard; Gömöry, F.; ten Kate, Herman H.J.

    1998-01-01

    The self-field loss of BSCCOrAg tapes has been measured in combination with an external AC magnetic field. This situation occurs when conductors are used in applications such as coils or cables. An increase of the self-field loss due to external AC magnetic field is observed. An increase of the

  8. [A Case of Ruptured Anterior Communicating Artery Aneurysm with Visual Field Defects and Deteriorating to Severe Vision Loss].

    Science.gov (United States)

    Sakakura, Kazuki; Ikeda, Go; Nakai, Yasunobu; Watanabe, Noriyuki; Shiigai, Masanari; Uemura, Kazuya; Yamamoto, Tetsuya; Matsumura, Akira

    2017-10-01

    Although Terson's syndrome is a well-known cause of vision loss due to intracerebral aneurysm rupture, optic nerve neuropathy can also occur because of other causes. Here, we report such a case, i.e., a ruptured anterior communicating artery aneurysm accompanied by vision loss and visual field disturbances due to a cause other than Terson's syndrome. A 47-year-old man presented with right superior altitudinal hemianopia. Computed tomography (CT) showed subarachnoid hemorrhage (SAH), and three-dimensional CT angiography revealed an anterior communicating artery aneurysm. Coil embolization was performed. Right visual acuity degenerated to blindness in the acute stage. MRI performed on day 7 post-admission revealed that the aneurysm had swollen and made contact with the right optic disk. On the basis of the patient's clinical course, we believe that the deterioration in his visual acuity could have been due to ischemic optic neuropathy (ION) resulting from SAH, and the subsequent edema and poor blood perfusion may be attributed to spasm. In cases of visual disturbance associated with SAH, as in our case, it is important to perform MRI to evaluate the damage or risk to the optic nerve as soon as possible. (Received December 26, 2016; Accepted June 9, 2017; Published October 1, 2017).

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

    Directory of Open Access Journals (Sweden)

    Julián N. Lescano

    2015-09-01

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

  10. 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

  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. 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...

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

    NARCIS (Netherlands)

    Petzold, A.; Islam, N.; Plant, G.T.

    2013-01-01

    The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical

  14. Experimental simulation of pulsed field losses in tokamak toroidal field coils

    International Nuclear Information System (INIS)

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

    1976-01-01

    Experiments have been carried out to measure loss in a twisted multifilamentary composite superconductor when exposed to a transient longitudinal field. We investigate the variation of losses both as a function of transverse applied field and of sample transport current. Losses are probed mainly by measurement of the dynamic resistivity of the sample during the longitudinal pulse. Experimental results are compared with theories for the zero transport current case. The extension of theory to include transport current is also discussed, and the impact on tokamak toroidal field coil design is considered

  15. Rotor Field Oriented Control with adaptive Iron Loss Compensation

    DEFF Research Database (Denmark)

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

    1999-01-01

    It is well known from the literature that iron loses in an induction motor implies field angle estimation errors and hence detuning problems. In this paper a new method for estimating the iron loss resistor in an induction motor is presented. The method is based on a traditional dynamic model...... of 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...

  16. 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

  17. 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.

  18. Recognizing patterns of visual field loss using unsupervised machine learning

    Science.gov (United States)

    Yousefi, Siamak; Goldbaum, Michael H.; Zangwill, Linda M.; Medeiros, Felipe A.; Bowd, Christopher

    2014-03-01

    Glaucoma is a potentially blinding optic neuropathy that results in a decrease in visual sensitivity. Visual field abnormalities (decreased visual sensitivity on psychophysical tests) are the primary means of glaucoma diagnosis. One form of visual field testing is Frequency Doubling Technology (FDT) that tests sensitivity at 52 points within the visual field. Like other psychophysical tests used in clinical practice, FDT results yield specific patterns of defect indicative of the disease. We used Gaussian Mixture Model with Expectation Maximization (GEM), (EM is used to estimate the model parameters) to automatically separate FDT data into clusters of normal and abnormal eyes. Principal component analysis (PCA) was used to decompose each cluster into different axes (patterns). FDT measurements were obtained from 1,190 eyes with normal FDT results and 786 eyes with abnormal (i.e., glaucomatous) FDT results, recruited from a university-based, longitudinal, multi-center, clinical study on glaucoma. The GEM input was the 52-point FDT threshold sensitivities for all eyes. The optimal GEM model separated the FDT fields into 3 clusters. Cluster 1 contained 94% normal fields (94% specificity) and clusters 2 and 3 combined, contained 77% abnormal fields (77% sensitivity). For clusters 1, 2 and 3 the optimal number of PCA-identified axes were 2, 2 and 5, respectively. GEM with PCA successfully separated FDT fields from healthy and glaucoma eyes and identified familiar glaucomatous patterns of loss.

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

    Science.gov (United States)

    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.

  20. Quantifying Nitrogen Loss From Flooded Hawaiian Taro Fields

    Science.gov (United States)

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

    2010-12-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  2. Monocular and binocular smooth pursuit in central field loss.

    Science.gov (United States)

    Shanidze, Natela; Heinen, Stephen; Verghese, Preeti

    2017-12-01

    Macular degeneration results in heterogeneous central field loss (CFL) and often has asymmetrical effects in the two eyes. As such, it is not clear to what degree the movements of the two eyes are coordinated. To address this issue, we examined smooth pursuit quantitatively in CFL participants during binocular viewing and compared it to the monocular viewing case. We also examined coordination of the two eyes during smooth pursuit and how this coordination was affected by interocular ratios of acuity and contrast, as well as CFL-specific interocular differences, such as scotoma sizes and degree of binocular overlap. We hypothesized that the coordination of eye movements would depend on the binocularity of the two eyes. To test our hypotheses, we used a modified step-ramp paradigm, and measured pursuit in both eyes while viewing was binocular, or monocular with the dominant or non-dominant eye. Data for CFL participants and age-matched controls were examined at the group, within-group, and individual levels. We found that CFL participants had a broader range of smooth pursuit gains and a significantly lower correlation between the two eyes, as compared to controls. Across both CFL and control groups, smooth pursuit gain and correlation between the eyes are best predicted by the ratio of contrast sensitivity between the eyes. For the subgroup of participants with measurable stereopsis, both smooth pursuit gain and correlation are best predicted by stereoacuity. Therefore, our results suggest that coordination between the eyes during smooth pursuit depends on binocular cooperation between the eyes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Asymmetrical local adaptation of maize landraces along an altitudinal gradient.

    Science.gov (United States)

    Mercer, Kristin; Martínez-Vásquez, Ángel; Perales, Hugo R

    2008-08-01

    Crop landraces are managed populations that evolve in response to gene flow and selection. Cross-pollination among fields, seed sharing by farmers, and selection by management and environmental conditions play roles in shaping crop characteristics. We used common gardens to explore the local adaptation of maize (Zea mays ssp. mays) landrace populations from Chiapas, Mexico to altitude. We sowed seeds of 21 populations from three altitudinal ranges in two common gardens and measured two characteristics that estimate fitness: likelihood of producing good quality seed and the total mass of good quality seed per plant. The probability of lowland plants producing good quality seed was invariably high regardless of garden, while highland landraces were especially sensitive to altitude. Their likelihood of producing good seed quadrupled in the highland site. The mass of good quality seed showed a different pattern, with lowland landraces producing 25% less seed mass than the other types at high elevations. Combining these two measures of fitness revealed that the highland landraces were clearly adapted to highland sites, while lowland and midland landraces appear more adapted to the midland site. We discuss this asymmetry in local adaptation in light of climate change and in situ conservation of crop genetic resources.

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

    African Journals Online (AJOL)

    A farm survey was conducted in subsistence farming communities to document the major grain crops, insect pests, indigenous pest control methods (PCM) and farmer perceptions of grain losses associated with identifiable pest species and perceived efficacies of the PCMs. Maize, beans and sorghum were identified as the ...

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

    Science.gov (United States)

    Rowe, Fiona J.; Wright, David; Brand, Darren; Jackson, Carole; Harrison, Shirley; Maan, Tallat; Vogwell, Linda; Peel, Sarah; Akerman, Nicola; Shipman, Tracey; Sperring, Una; MacDiarmid, Sonia; Freeman, Cicely

    2013-01-01

    Aims. To profile site of stroke/cerebrovascular accident, type and extent of field loss, treatment options, and outcome. Methods. Prospective multicentre cohort trial. Standardised referral and investigation protocol of visual parameters. Results. 915 patients were recruited with a mean age of 69 years (SD 14). 479 patients (52%) had visual field loss. 51 patients (10%) had no visual symptoms. Almost half of symptomatic patients (n = 226) complained only of visual field loss: almost half (n = 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. PMID:24089687

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. Altitudinal variation in metabolic parameters of a small Afrotropical bird.

    Science.gov (United States)

    Thompson, Lindy J; Downs, Colleen T

    2017-10-01

    Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (T a ). Cape White-eyes were 0.8g heavier at the higher altitude site and 0.5g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing T a , as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Field Loss Estimation Of A Developed Rice Stripper Harvester In Nigeria

    Directory of Open Access Journals (Sweden)

    2016-11-01

    Full Text Available Reduction in post harvest losses must inevitably start with minimizing losses during harvesting. So far, grain stripping harvester is a technology which is being developed and is becoming effective for rice and wheat harvesting. Grain losses in stripping harvester occur at the gathering/stripping operation which are shattering, stubble and lodging losses. The harvest loss estimation of rice harvesting with a self propelled grain stripper developed in Nigeria was carried out. At best machine settings, determined were critical operating parameters to obtain total minimum harvest loss estimation which was 13.5% of the total yield while the manual harvesting loss was 20.3% under the same condition. The machine setting at this combination was rotor height of 270.0 mm, peripheral rotor speed of 670.0 rpm and forward speed was 3.0 km/h which gave shattering loss as 5.5%, stubble loss was 4.9% and lodging loss was 3.1% of the total yield. It was found that planting pure seed variety will reduce stripper header losses at harvest because it will result in uniform crop height at maturity which was one of the design factors that affected the harvester performance on the field. Keywords:Estimation, field loss, stripper, rice, developed

  12. 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...

  13. Altitudinal variation of some morphological characters of Scots pine ...

    African Journals Online (AJOL)

    The objective of this study was to investigate the altitudinal variation within and between Scots pine (Pinus sylvestris L.) populations in Turkey using 23 morphological characters. Seeds were collected from 149 open-pollinated parents (trees) from five populations sampled from different altitudes in the natural distribution ...

  14. Effects of habitat structure and altitudinal gradients on avian species ...

    African Journals Online (AJOL)

    Using line transect methods, the effect of habitat structure and altitudinal gradients on bird species diversity at Kurra Falls Forest were studied. A total of 175 bird species were recorded, two of which are among the four endemic birds to Nigeria. Tree height, tree number, and canopy cover together had a significant effect on ...

  15. Light-driven altitudinal molecular motors on surfaces

    NARCIS (Netherlands)

    London, Gabor; Carroll, Gregory T.; Fernández Landaluce, Tatiana; Pollard, Michael M.; Rudolf, Petra; Feringa, Ben L.

    2009-01-01

    A Cu(I)-catalyzed 1,3-dipolar cycloaddition was used to construct a monolayer of an altitudinal molecular motor on quartz and silicon substrates, which represents the fastest light-driven molecular motor, to date, grafted to a solid surface.

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

    Science.gov (United States)

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

    2014-01-01

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

  17. 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).

  18. Computations of AC Loss in the ITER Magnets during Fast Field Transients

    CERN Document Server

    Bottura, Luca; Lister, Jonathan B; Marinucci, Claudio; Portone, Alfredo

    2007-01-01

    The calculation of AC loss due to the control currents in ITER is a cumbersome task. The reason is that control transients require small field changes (0.1 T or less) at moderate frequency (up to 10 Hz), where effects of partial penetration of the filaments and shielding are important and need to be taken into account to produce sound AC loss estimates. In this paper we describe models developed for AC loss calculation, in particular hysteresis and coupling current loss, that are suitable for the above regime. Both hysteresis and coupling loss models are adapted to the conductor analyzed through few parameters (the effective filament diameter and time constants) that can be derived from measurement of loss on short samples. We report an example of calculations of AC loss in the ITER TF and PF coils for two vertical control scenarios (VS1 and VS2) during high beta operation at flattop.

  19. Partial altitudinal migration of a Himalayan Forest pheasant.

    Science.gov (United States)

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

    2013-01-01

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

  20. Partial altitudinal migration of a Himalayan Forest pheasant.

    Directory of Open Access Journals (Sweden)

    Nawang Norbu

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

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

    Directory of Open Access Journals (Sweden)

    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

  2. Causes of incident visual field loss in a general elderly population: the Rotterdam study

    NARCIS (Netherlands)

    Skenduli-Bala, Elisa; de Voogd, Simone; Wolfs, Roger C. W.; van Leeuwen, Redmer; Ikram, M. Kamran; Jonas, Jost B.; Bakker, Douwe; Hofman, Albert; de Jong, Paulus T. V. M.

    2005-01-01

    To determine the incidence and causes of visual field loss (VFL) in a general elderly population. Central visual fields of both eyes were examined with suprathreshold perimetry in 3761 persons aged 55 years or older and free of VFL at baseline from the population-based Rotterdam Study. Goldmann

  3. 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)

  4. Seasonal Manure Application Timing and Storage Effects on Field- and Watershed-Level Phosphorus Losses.

    Science.gov (United States)

    Liu, Jian; Veith, Tamie L; Collick, Amy S; Kleinman, Peter J A; Beegle, Douglas B; Bryant, Ray B

    2017-11-01

    Timing of manure application to agricultural soils remains a contentious topic in nutrient management planning, particularly with regard to impacts on nutrient loss in runoff and downstream water quality. We evaluated the effects of seasonal manure application and associated manure storage capacity on phosphorus (P) losses at both field and watershed scales over an 11-yr period, using long-term observed data and an upgraded, variable-source water quality model called Topo-SWAT. At the field level, despite variation in location and crop management, manure applications throughout fall and winter increased annual total P losses by 12 to 16% and dissolved P by 19 to 40% as compared with spring. Among all field-level scenarios, total P loss was substantially reduced through better site targeting (by 48-64%), improving winter soil cover (by 25-46%), and reducing manure application rates (by 1-23%). At the watershed level, a scenario simulating 12 mo of manure storage (all watershed manure applied in spring) reduced dissolved P loss by 5% and total P loss by 2% but resulted in greater P concentrations peaks compared with scenarios simulating 6 mo (fall-spring application) or 3 mo storage (four-season application). Watershed-level impacts are complicated by aggregate effects, both spatial and temporal, of manure storage capacity on variables such as manure application rate and timing, and complexities of field and management. This comparison of the consequences of different manure storage capacities demonstrated a tradeoff between reducing annual P loss through a few high-concentration runoff events and increasing the frequency of low peaks but also increasing the annual loss. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  5. 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.

  6. 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.

  7. 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)

  8. 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)

  9. Embolic and Nonembolic Transient Monocular Visual Field Loss: A Clinicopathologic Review

    NARCIS (Netherlands)

    Petzold, A.; Islam, N.; Hu, H.H.; Plant, G.T.

    2013-01-01

    Transient monocular blindness and amaurosis fugax are umbrella terms describing a range of patterns of transient monocular visual field loss (TMVL). The incidence rises from ≈1.5/100,000 in the third decade of life to ≈32/100,000 in the seventh decade of life. We review the vascular supply of the

  10. 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

  11. 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.

  12. Applicability of models to predict phosphorus losses in drained fields: a review.

    Science.gov (United States)

    Radcliffe, David E; Reid, D Keith; Blombäck, Karin; Bolster, Carl H; Collick, Amy S; Easton, Zachary M; Francesconi, Wendy; Fuka, Daniel R; Johnsson, Holger; King, Kevin; Larsbo, Mats; Youssef, Mohamed A; Mulkey, Alisha S; Nelson, Nathan O; Persson, Kristian; Ramirez-Avila, John J; Schmieder, Frank; Smith, Douglas R

    2015-03-01

    Most phosphorus (P) modeling studies of water quality have focused on surface runoff loses. However, a growing number of experimental studies have shown that P losses can occur in drainage water from artificially drained fields. In this review, we assess the applicability of nine models to predict this type of P loss. A model of P movement in artificially drained systems will likely need to account for the partitioning of water and P into runoff, macropore flow, and matrix flow. Within the soil profile, sorption and desorption of dissolved P and filtering of particulate P will be important. Eight models are reviewed (ADAPT, APEX, DRAINMOD, HSPF, HYDRUS, ICECREAMDB, PLEASE, and SWAT) along with P Indexes. Few of the models are designed to address P loss in drainage waters. Although the SWAT model has been used extensively for modeling P loss in runoff and includes tile drain flow, P losses are not simulated in tile drain flow. ADAPT, HSPF, and most P Indexes do not simulate flow to tiles or drains. DRAINMOD simulates drains but does not simulate P. The ICECREAMDB model from Sweden is an exception in that it is designed specifically for P losses in drainage water. This model seems to be a promising, parsimonious approach in simulating critical processes, but it needs to be tested. Field experiments using a nested, paired research design are needed to improve P models for artificially drained fields. Regardless of the model used, it is imperative that uncertainty in model predictions be assessed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  13. The impact of visual field loss on driving performance: evidence from on-road driving assessments.

    Science.gov (United States)

    Racette, Lyne; Casson, Evanne J

    2005-08-01

    The purpose of this study was to investigate the relationship between visual field loss and driving performance as determined by on-road driving assessments. We reviewed the files of 1350 patients enrolled in a rehabilitation program at the Bloorview MacMillan Rehabilitation Centre, Toronto, Canada. We identified 131 patients with visual field loss who had undergone an on-road driving assessment. These patients had a primary diagnosis of visual impairment or a primary diagnosis of cerebral vascular accident (CVA) with a secondary diagnosis of visual impairment. None of these patients had documentation of neglect, substantial motor or cognitive deficits. We report the data obtained from 13 hemianopics, 7 quadrantanopics, 25 patients with monocular vision, 10 patients with moderate peripheral losses (worse impact on driving performance than quadrantanopia with a marginally significant result (chi2 = 3.33, p = 0.068). Overall, the location of the visual loss was not significantly related to driving fitness (chi2 = 1.05, p = 0.30). However, localized defects in the left hemifield (chi2 = 9.561, p = 0.002) and diffuse visual loss in the right hemifield (chi2 = 10.395, p = 0.001) seemed to be associated with driving impairments. A large proportion of monocular drivers were safe drivers and the location of their deficit had no significant impact. Although the extent of visual field defects appears to be related to driving performance as determined by an on-road driving assessment, large individual differences were observed. This highlights the need for individualized on-road assessments for patients with visual field defects.

  14. Performance of the visual field index in glaucoma patients with moderately advanced visual field loss.

    Science.gov (United States)

    Lee, Jun Mo; Cirineo, Nila; Ramanathan, Meera; Nouri-Mahdavi, Kouros; Morales, Esteban; Coleman, Anne L; Caprioli, Joseph

    2014-01-01

    To explore the relationship between the visual field index (VFI) and the visual field mean deviation (MD) in glaucoma patients with moderately advanced perimetric damage and to identify the magnitude of the boundary effect of VFI that occurred when the VFI estimation strategy changed from pattern deviation probability value to total deviation probability value as the MD crossed -20 dB in longitudinal visual field (VF) series. A retrospective cohort study of longitudinal data analysis. The MD and VFI values obtained from VF tests conducted on 148 eyes of 148 glaucoma patients having an MD around -20 dB were studied. A total of 1286 VFs with MD values within the range of -16 dB to -24 dB were included. The eyes were divided into 2 groups, with the first having serial MDs all better than or all worse than -20 dB and the second with serial MDs crossing the -20 dB value. Change in MD (ΔMD) was defined as the absolute difference between the MD values of 2 consecutive VFs. Based on the 2 VFI values of the same VFs, the absolute value of change in VFI (ΔVFI) was calculated. The means (± standard deviation) for the ΔVFI were 4.17% (± 3.3%) in the group of eyes with MDs on either side of -20 dB, and were 15.8% (± 8.4%) in the group with MDs crossing -20 dB (P values were 6.8%/dB (± 10.5%) when the range of MD falls on either side of -20 dB, and 7.9%/dB (± 6.2%) when the range of MD crosses the -20 dB values (P = .042). The values of the VFI become highly variable in serial VFs of eyes with MDs crossing -20 dB, in comparison to those VFIs associated with MDs on either side of -20 dB. The likelihood for this effect is the change from use of pattern deviation probability value to total deviation probability value in the points included in the calculation of VFI at -20 dB of MD. The development of indices to measure VF rates that are free from this boundary effect in moderately advanced glaucoma is desirable. Copyright © 2014. Published by Elsevier Inc.

  15. 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.

  16. Current distribution and losses inside a superconducting multiwire composite submitted to a variable magnetic field

    International Nuclear Information System (INIS)

    Ciazynski, D.

    1985-11-01

    The work performed concerns essentially the current saturation effect of superconducting filaments part of a composite, on current distribution and losses, created by a varying magnetic field, transverse to the composite. Induced current and losses created in the composite are first studied in an homogeneous medium. The theoretical resolution is then made from Maxwell equations and characteristic equations of the medium. Then, from the homogeneous model a complete system of equations is got for four cases: the steady state conditions (constant induced current) for a composite not carrying currents; the non-homogeneous composites in the same conditions; the third case is about influence of carried current in steady-state conditions, and finally the transient regime. A method of numerical solution allows to calculate currents and losses dissipated inside the composite. In every case, an experimental study completes the theoretical studies [fr

  17. A method to assess the loss of a dipole antenna for ultra-high-field MRI.

    Science.gov (United States)

    Chen, Gang; Collins, Christopher M; Sodickson, Daniel K; Wiggins, Graham C

    2018-03-01

    To describe a new bench measurement based on quality (Q) factors to estimate the coil noise relative to the sample noise of dipole antennas at 7 T. Placing a dipole antenna close to a highly conductive sample surrogate (HCSS) greatly reduces radiation loss, and using Q HCSS gives a more accurate estimate of coil resistance than Q unloaded . Instead of using the ratio of unloaded and sample-loaded Q factors, the ratio of HCSS-loaded and sample-loaded Q factors should be used at ultra-high fields. A series of simulations were carried out to analyze the power budget of sample-loaded or HCSS-loaded dipole antennas. Two prototype dipole antennas were also constructed for bench measurements to validate the simulations. Simulations showed that radiation loss was suppressed when the dipole antenna was HCSS-loaded, and coil loss was largely the same as when the dipole was loaded by the sample. Bench measurements also showed good alignment with simulations. Using the ratio Q HCSS /Q loaded gives a good estimate of the coil loss for dipole antennas at 7 T, and provides a convenient bench measurement to predict the body noise dominance of dipole antenna designs. The new approach also applies to conventional surface loop coils at ultra-high fields. Magn Reson Med 79:1773-1780, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  18. 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.

  19. 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.

  20. Comparison of budburst dynamics between species on altitudinal gradient

    Science.gov (United States)

    Davi, H.; Gillmann, M.; Ibanez, T.

    2009-04-01

    Phenology of plants is a key ecosystem parameter controlling carbon and water fluxes and also acting on the dynamics of communities. This parameter is highly sensitive to the climate and consequently is often used as a proxy of global change. In this paper, we attempt to analyse the dynamics of budburst every week for seven species (Fagus sylvatica L., Acer opalus Mill , Sorbus aria L., Quercus pubescens Willd. Abies alba Mill., Pinus sylvestris L., Pinus nigra Arnold) in two altitudinal gradients, one in a northern slope and one in a southern slope in the Ventoux mountain. The originality of this work is to assess not only the budburst date but to more precisely analyse the dynamics of budburst and its variation with altitude according to the species. Two important results are highlighted. First, the dynamics of budburst changes according to the species. Three distinct patterns can be drawn, a rapid sigmoid increase for the deciduous species, a short sigmoid increase for the pines and an intermediate curve for silver fir. These dynamics can be slowing down for coniferous when frost arises during the budburst. The second topic is the link between budburst and temperature by analysing respectively the year, the altitudinal and the aspect (north and south) effects. In 2007, budburst occurs earlier for Fagus, Acer, and Abies, it does not change for pines and is delayed for Sorbus. Date of beech budburst is the same between north and south in spite of higher temperature in south. The altitude effect on budburst varies greatly according to species and the year with a weak effect on Fagus and a stronger effect for the others species showing a threshold at 1200 m. By analysing the mean of temperatures at each altitude, we conclude that temperature effect acts differently between years or between altitudes. To conclude, we highlighted the complex effect of temperatures on budburst varying between species and situations.

  1. Surface and Subsurface Transport of Nitrate Loss from the Selected Bioenergy Crop Fields: Systematic Review, Analysis and Future Directions

    Directory of Open Access Journals (Sweden)

    Suresh Sharma

    2017-03-01

    Full Text Available Nitrate loss from bioenergy crop fields has attracted considerable attention during the last few years because of its potential negative impact on aquatic and human health. Both controllable and uncontrollable factors for nitrate loss have been the subject of several previous studies. Due to differences in climate, biophysical dissimilarities and land management characteristics in different parts of the world the factors affecting nitrate loss are often inconsistent and hence difficult to generalize. Therefore, reanalyzing the experimental field or plot scale studies to understand the nitrate loss factors in crop fields is useful and necessary in developing management strategies for reducing nitrate loss. This research synthesized and investigated 36 peer reviewed scientific journal articles related to selected bioenergy crop fields that included: continuous corn, corn in rotation with soybean, switchgrass and Miscanthus to conduct a meta-analysis of the available research. In this study, factors such as drain tile spacing, tillage practices, type and timing of the fertilization rate, irrigation and various other factors, which are challenging to represent in regression equations, were also systematically analyzed. In addition, various other agronomic characteristics that are attributed too nitrate loss are caused by perennially planted bio energized crops such as Miscanthus and switchgrass. Results indicated that 49% of nitrate loss through surface runoff from corn fields is directly related to the annual precipitation and fertilization rate. Multiple linear regression equations were developed to estimate the annual subsurface nitrate loss for the continuous corn fields with a R2 value of 0.65, 0.58 and 0.26 for sandy loam, silty loam and clay loam, respectively. Our analysis resulted in the conclusion that corn has a 2 to 3 times higher nitrate loss in surface runoff compared to switchgrass. Likewise, continuous corn and corn in rotation with

  2. 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.

  3. 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.

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

    OpenAIRE

    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 ...

  5. 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.

  6. 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

  7. 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.

  8. Magnetic field shielding by vacuum chambers of magnetic material for beam loss reduction

    International Nuclear Information System (INIS)

    Kamiya, Junichiro; Ogiwara, Norio; Hayashi, Naoki; Hotchi, Hideaki; Yoshimoto, Masahiro; Kinsho, Michikazu

    2012-01-01

    One of the reasons of a beam loss in a high power accelerator is leakage magnetic field from a magnet at a close beam line, which distorts the beam orbit and makes the beam hit the wall of the beam pipe. The most effective way to shield such leakage field is to cover the beam by the magnetic materials at the nearest space. This means that beam pipes and bellows be made of the magnetic materials. We plan to apply this method to the vacuum chambers of the beam extraction section of the J-PARC 3 GeV synchrotron, where the effect of the leakage magnetic field to the beam orbit is evident. However, there is few proven evidence of the vacuum chambers made of magnetic materials. Therefore we clarify the problems in producing beam pipes and bellows, which satisfy the magnetic and vacuum performance. In this article, we deliver the over view of the magnetic shielding project and our approaches to the problems in producing the vacuum chambers of magnetic materials. (author)

  9. The impact of pulsed electric fields and ultrasound on water distribution and loss in mushrooms stalks.

    Science.gov (United States)

    Dellarosa, Nicolò; Frontuto, Daniele; Laghi, Luca; Dalla Rosa, Marco; Lyng, James G

    2017-12-01

    Pulsed electric fields (PEF) and ultrasound (US) are promising innovative technologies with the potential to increase mass transfer when combined with further processes which in turn can provide potential benefits in the recovery of valuable compounds from food by-products. To provide evidence of the mechanism of mass transfer enhancement, the present study assessed the impact of PEF and US treatments, applied individually and in combination, at low and high temperatures, on the tissue microstructure of mushroom stalks. Different indices such as quantitative water redistribution, water loss and qualitative release of compounds were evaluated. The combination of these physical methods demonstrated that PEF redistributed a greater proportion of intracellular water into extracellular spaces than US. However, the application of high temperature treatments alone showed an even greater proportion of intracellular water migration compared to PEF. When PEF was combined with US at low temperatures the difference was not significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Scientific Objectives of Electron Losses and Fields INvestigation Onboard Lomonosov Satellite

    Science.gov (United States)

    Shprits, Y. Y.; Angelopoulos, V.; Russell, C. T.; Strangeway, R. J.; Runov, A.; Turner, D.; Caron, R.; Cruce, P.; Leneman, D.; Michaelis, I.; Petrov, V.; Panasyuk, M.; Yashin, I.; Drozdov, A.; Russell, C. L.; Kalegaev, V.; Nazarkov, I.; Clemmons, J. H.

    2018-02-01

    The objective of the Electron Losses and Fields INvestigation on board the Lomonosov satellite (ELFIN-L) project is to determine the energy spectrum of precipitating energetic electrons and ions and, together with other polar-orbiting and equatorial missions, to better understand the mechanisms responsible for scattering these particles into the atmosphere. This mission will provide detailed measurements of the radiation environment at low altitudes. The 400-500 km sun-synchronous orbit of Lomonosov is ideal for observing electrons and ions precipitating into the atmosphere. This mission provides a unique opportunity to test the instruments. Similar suite of instruments will be flown in the future NSF- and NASA-supported spinning CubeSat ELFIN satellites which will augment current measurements by providing detailed information on pitch-angle distributions of precipitating and trapped particles.

  11. 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.

  12. Experimental determination of the frequency and field dependence of Specific Loss Power in Magnetic Fluid Hyperthermia

    Science.gov (United States)

    Cobianchi, M.; Guerrini, A.; Avolio, M.; Innocenti, C.; Corti, M.; Arosio, P.; Orsini, F.; Sangregorio, C.; Lascialfari, A.

    2017-12-01

    Magnetic nanoparticles are promising systems for biomedical applications and in particular for Magnetic Fluid Hyperthermia, a therapy that utilizes the heat released by such systems to damage tumor cells. We present an experimental study of the physical properties that influences the capability of heat release, i.e. the Specific Loss Power, SLP, of three biocompatible ferrofluid samples having a magnetic core of maghemite with different diameter d = 10.2, 14.6 and 19.7 nm. The SLP was measured as a function of frequency f and intensity H of the applied alternating magnetic field, and it turned out to depend on the core diameter, as expected. The results allowed us to highlight experimentally that the physical mechanism responsible for the heating is size-dependent and to establish, at applied constant frequency, the phenomenological functional relationship SLP = c·Hx, with 2 ≤ xmagnetic hyperthermia devices. For the smallest sample, the effective relaxation time τeff ≈ 19.5 ns obtained from SLP data is in agreement with the value estimated from magnetization data, thus confirming the validity of the Linear Response Theory model for this system at properly chosen field intensity and frequency.

  13. Influence of field penetration ratios and filamentation on end-effect related hysteretic loss reductions for superconducting strips

    Science.gov (United States)

    Dong, K.; Sumption, M.; Collings, E. W.; Majoros, M.; Yu, H.; Hu, M.

    2017-12-01

    There are a few key conductor-specific factors which influence the power loss of superconductors; these include critical current, geometry, and normal metal resistivity. This paper focuses on the influence of sample geometry on the power loss of superconducting strips and the effect of filamentation and sample length as a function of the field penetration state of the superconductor. We start with the analytical equations for infinite slabs and strips and then consider the influence of end effects for both unstriated and striated conductor. The loss is then calculated and compared as a function of applied field for striated and unstriated conductors. These results are much more general than they might seem at first glance, since they will be important building blocks for analytic loss calculations for twisted geometries for coated conductors, including helical (Conductor on Round Core, CORC), and twisted (e.g., twist stack cables) geometries. We show that for relatively low field penetration, end effects and reduced field penetration both reduce loss. In addition, for filamentary samples the relevant ratio of length scales becomes the filament width to sample length, thus modifying the loss ratios.

  14. 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

    with different numbers of slots per pole per phase. The necessity of an electromagnetic shield is then discussed based on the obtained loss levels. The results show that the total ac loss is so small that ferromagnetic teeth can be applied in the generator design without using an electromagnetic shield....

  15. 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.

  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. Analytical Calculation of Magnetic Field Distribution and Stator Iron Losses for Surface-Mounted Permanent Magnet Synchronous Machines

    Directory of Open Access Journals (Sweden)

    Zhen Tian

    2017-03-01

    Full Text Available Permanent-magnet synchronous machines (PMSMs are widely used in electric vehicles owing to many advantages, such as high power density, high efficiency, etc. Iron losses can account for a significant component of the total loss in permanent-magnet (PM machines. Consequently, these losses should be carefully considered during the PMSM design. In this paper, an analytical calculation method has been proposed to predict the magnetic field distribution and stator iron losses in the surface-mounted permanent magnet (SPM synchronous machines. The method introduces the notion of complex relative air-gap permeance to take into account the effect of slotting. The imaginary part of the relative air-gap permeance is neglected to simplify the calculation of the magnetic field distribution in the slotted air gap for the surface-mounted permanent-magnet (SPM machine. Based on the armature reaction magnetic field analysis, the stator iron losses can be estimated by the modified Steinmetz equation. The stator iron losses under load conditions are calculated according to the varying d-q-axis currents of different control methods. In order to verify the analysis method, finite element simulation results are compared with analytical calculations. The comparisons show good performance of the proposed analytical method.

  18. Beneficial Effects of Spatial Remapping for Reading With Simulated Central Field Loss.

    Science.gov (United States)

    Gupta, Anshul; Mesik, Juraj; Engel, Stephen A; Smith, Rebecca; Schatza, Mark; Calabrèse, Aurélie; van Kuijk, Frederik J; Erdman, Arthur G; Legge, Gordon E

    2018-02-01

    People with central field loss (CFL) lose information in the scotomatous region. Remapping is a method to modify images to present the missing information outside the scotoma. This study tested the hypothesis that remapping improves reading performance for subjects with simulated CFL. Circular central scotomas, with diameters ranging from 4° to 16°, were simulated in normally sighted subjects using an eye tracker on either a head-mounted display (HMD) (experiments 1, 2) or a traditional monitor (experiment 3). In the three experiments, reading speed was measured for groups of 7, 11, and 13 subjects with and without remapping of text. Remapping increased reading speed in all three experiments. On the traditional monitor, it increased reading speed by 34% (8°), 38% (12°), and 35% (16°). In the two HMD experiments, remapping increased reading speed only for the largest scotoma size, possibly due to latency of updating of the simulated scotoma. Remapping significantly increased reading speed in simulated CFL subjects. Additional testing should examine the efficacy of remapping for reading and other visual tasks for patients with advanced CFL.

  19. 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.

  20. Do Stacked Species Distribution Models Reflect Altitudinal Diversity Patterns?

    Science.gov (United States)

    Mateo, Rubén G.; Felicísimo, Ángel M.; Pottier, Julien; Guisan, Antoine; Muñoz, Jesús

    2012-01-01

    The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species) and the Bromeliaceae family (89 species) using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence). By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m) was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be developed. PMID

  1. Altitudinal changes in temperature responses of net photosynthesis and dark respiration in tropical bryophytes.

    Science.gov (United States)

    Wagner, Sebastian; Zotz, Gerhard; Salazar Allen, Noris; Bader, Maaike Y

    2013-03-01

    There is a conspicuous increase of poikilohydric organisms (mosses, liverworts and macrolichens) with altitude in the tropics. This study addresses the hypothesis that the lack of bryophytes in the lowlands is due to high-temperature effects on the carbon balance. In particular, it is tested experimentally whether temperature responses of CO(2)-exchange rates would lead to higher respiratory carbon losses at night, relative to potential daily gains, in lowland compared with lower montane forests. Gas-exchange measurements were used to determine water-, light-, CO(2)- and temperature-response curves of net photosynthesis and dark respiration of 18 tropical bryophyte species from three altitudes (sea level, 500 m and 1200 m) in Panama. Optimum temperatures of net photosynthesis were closely related to mean temperatures in the habitats in which the species grew at the different altitudes. The ratio of dark respiration to net photosynthesis at mean ambient night and day temperatures did not, as expected, decrease with altitude. Water-, light- and CO(2)-responses varied between species but not systematically with altitude. Drivers other than temperature-dependent metabolic rates must be more important in explaining the altitudinal gradient in bryophyte abundance. This does not discard near-zero carbon balances as a major problem for lowland species, but the main effect of temperature probably lies in increasing evaporation rates, thus restricting the time available for photosynthetic carbon gain, rather than in increasing nightly respiration rates. Since optimum temperatures for photosynthesis were so fine tuned to habitat temperatures we analysed published temperature responses of bryophyte species worldwide and found the same pattern on the large scale as we found along the tropical mountain slope we studied.

  2. 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.

  3. Painful shoulder? Remote clinical management of a Field Guide with shoulder pain and loss of shoulder function in Antarctica

    Directory of Open Access Journals (Sweden)

    Gareth Jones

    2017-06-01

    Full Text Available We report the case of a female Field Guide based at the British Antarctic Survey’s Rothera Science Research Station on Adelaide Island, Antarctica who independently contacted a physiotherapist specialising in climbing related injuries (GJ located in the UK. for a second opinion. The Field Guide was experiencing significant work difficulties due to shoulder pain and subsequent loss of function particularly in overhead activities. The case raises important issues about the medical management of Field Guides operating in extreme environments and remote locations

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

    Directory of Open Access Journals (Sweden)

    Gracitelli CPB

    2013-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Francisco Mallet-Rodrigues

    2010-08-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

    A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood.We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western

  7. Towards Dynamic Control of Wettability by Using Functionalized Altitudinal Molecular Motors on Solid Surfaces

    NARCIS (Netherlands)

    London, Gabor; Chen, Kuang-Yen; Carroll, Gregory T.; Feringa, Ben L.

    2013-01-01

    We report the synthesis of altitudinal molecular motors that contain functional groups in their rotor part. In an approach to achieve dynamic control over the properties of solid surfaces, a hydrophobic perfluorobutyl chain and a relatively hydrophilic cyano group were introduced to the rotor part

  8. 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

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

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2003-01-01

    Altitudinal patterns in diversity of macroinvertebrate families at different spatial scales (stone, stream and altitude) were studied by collecting stone samples from six streams at each of the three altitudes: lowlands (400m), midlands (2000m) and highlands (3800 m), in the equatorial Andes...

  10. Vegetation patterns and plant communities distribution along an altitudinal gradient at asir mountain, southwest saudi arabia

    International Nuclear Information System (INIS)

    Ghazal, A.M.F.

    2015-01-01

    Vegetation composition, main plant communities and altitudinal vegetation zones at Asir Mountain southwest Saudi Arabia were studied, and in relation to various environmental factors including climatic, geological, ecological and topographic. A total of 74 plots were sampled according to Braun-Blanquet method along an altitudinal gradient. Floristic and environmental (topographic, geological and climatic) data were collected and analyzed using numerical classification and ordination. Two main climatic regions, four altitudinal vegetation zones and fifteen vegetation groups were identified: (1) two groups in an arid coastal plains mainly on an alluvial substratum between 0 and 200m (2) seven groups in the in terspersed hills and plateaus of Tihamah arid region from 200 to 1100m; (3) three groups in the escarpments from 1100 to 2000m in the semi-arid region; and (4) two groups in a semi-arid high mountains zone from 2000m to the summit. Geo-altitudinal gradient was affected by the climatic factors (rainfall and temperature) and vegetation structure (species richness and coverage) on a regional scale, while edaphic factors played the leading role in the distribution of different vegetation groups on a local scale. These findings coincide with those reported about the distribution of vegetation at other tropical mountains. Human activates have a significant effect on modifying the distribution and abundance of plant species. (author)

  11. Altitudinal variation in egg retention and rates of embryonic development in oviparous Zootoca vivipara fits predictions from the cold-climate model on the evolution of viviparity.

    Science.gov (United States)

    Rodríguez-Díaz, T; Braña, F

    2012-09-01

    The evolution of reptilian viviparity is favoured, according to the cold-climate hypothesis, at high latitudes or altitudes, where egg retention would entail thermal benefits for embryogenesis because of maternal thermoregulation. According to this hypothesis, and considering that viviparity would have evolved through a gradual increase in the extent of intrauterine egg retention, highland oviparous populations are expected to exhibit more advanced embryo development at oviposition than lowland populations. We tested for possible differences in the level of egg retention, embryo development time and thermal biology of oviparous Zootoca vivipara near the extreme altitudinal limits of the species distribution in the north of Spain (mean altitude for lowland populations, 235 m asl.; for highland populations, 1895 m asl.). Altitude influenced neither temperature of active lizards in the field nor temperature selected by lizards in a laboratory thermal gradient, and pregnant females selected lower temperatures in the thermal gradient than did males and nonpregnant females across altitudinal levels. Eggs from highland populations contained embryos more developed at the time of oviposition (Dufaure and Hubert's stages 33-35) than eggs of highland populations (stages 30-34) and partly because of this difference incubation time was shorter for highland embryos. When analysed for clutches from both altitudinal extremes at the same embryonic stage at oviposition (stage 33), again incubation time was shorter for highland populations, indicating genuine countergradient variation in developmental rate. Our results indicate that temperature is an environmental factor affecting the geographical distribution of different levels of egg retention in Z. vivipara, as predicted by the cold-climate hypothesis on the evolution of viviparity. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

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

    Directory of Open Access Journals (Sweden)

    Merav Gleit Kielmanowicz

    2015-04-01

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

  13. Prospective Large-Scale Field Study Generates Predictive Model Identifying Major Contributors to Colony Losses

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Erika Maliníková

    2013-07-01

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

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

    Science.gov (United States)

    Monteagudo Sabaté, David; Luis Martínez, Moisés Armando

    2013-09-01

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

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

    Science.gov (United States)

    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

  18. 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

  19. 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.

  20. Mapping of valence energy losses via energy-filtered annular dark-field scanning transmission electron microscopy.

    Science.gov (United States)

    Gu, Lin; Sigle, Wilfried; Koch, Christoph T; Nelayah, Jaysen; Srot, Vesna; van Aken, Peter A

    2009-08-01

    The advent of electron monochromators has opened new perspectives on electron energy-loss spectroscopy at low energy losses, including phenomena such as surface plasmon resonances or electron transitions from the valence to the conduction band. In this paper, we report first results making use of the combination of an energy filter and a post-filter annular dark-field detector. This instrumental design allows us to obtain energy-filtered (i.e. inelastic) annular dark-field images in scanning transmission electron microscopy of the 2-dimensional semiconductor band-gap distribution of a GaN/Al(45)Ga(55)N structure and of surface plasmon resonances of silver nanoprisms. In comparison to other approaches, the technique is less prone to inelastic delocalization and relativistic artefacts. The mixed contribution of elastic and inelastic contrast is discussed.

  1. 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

    A scanning near-field optical microscope is used to directly map the propagation of light in the wavelength range of 1500-1630 nm along straight photonic crystal waveguides (PCWs) fabricated on silicon-on-insulator wafers. The PVWs were formed by removing a single row of holes in the triangular 428......-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...

  2. 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.

  3. 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)

  4. 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)

  5. 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

  6. Loss of long range order in the 3D random field Ising model

    International Nuclear Information System (INIS)

    Hill, J.P.; Feng, Q.; Birgeneau, R.J.; Thurston, T.R.

    1993-01-01

    We report a synchrotron magnetic x-ray scattering study of the temperature evolution of the magnetic long range order (LRO) of Mn 0.75 Zn 0.25 F 2 in a magnetic field with emphasis on the behavior after zero field cooling (ZFC). We show that with increasing temperature the metastable ZFC LRO vanishes continuously at a temperature well above the equilibrium T N ; the LRO follows a rounded power law with exponent β ZFC =0.20±0.02 and a transition width which scales as ∼H 2 but with no divergent critical fluctuations. We argue that this behavior is generic to the random field Ising model

  7. The Potential to Reduce Nitrogen Loss Through Rotating Different Sorghum Varieties in Greenhouse Vegetable Field

    Directory of Open Access Journals (Sweden)

    KANG Ling-yun

    2015-06-01

    Full Text Available In North China plain, excessive fertilization in vegetable greenhouse always results in nitrate accumulation in soil and possible nitrogen leaching with potential environmental risk. It is necessary to rotate appropriate catch crop to absorb surplus nitrogen in fallow season and reduce rootzone nitrate level. An experiment was carried out to select suitable sorghum variety as catch crop to reduce nitrogen loss in Beijing suburb. Six common varieties were used in the experiment as conventional catch crop, sweet corn as the control. The results indicated that the biomass, root growth and nitrogen accumulation in shoots of sorghum Jinza 12 were highest in the catch crops. It demonstrated that the variety Jinza 12 was an appropriate catch crop for reducing nitrogen accumulation in surface soil layer compared with sweet corn. Meanwhile, variety Jiliang 2 maintained highest proportion of soil NH4+-N content after urea application, which might be related to the biological nitrification inhibitors (BNI released by the root system of sorghum. It implied that sorghum could be used as catch crop to reduce nitrogen loss through plant extraction i.e. nitrogen uptake and stabilization i.e. BNI inhibition, in comparison with sweet corn.

  8. 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.

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

    NARCIS (Netherlands)

    Whitmore, A.P.; Schröder, J.J.

    2007-01-01

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

  10. Magnetisation loss of BSCCO/Ag tape in uni-directional and rotating magnetic field

    NARCIS (Netherlands)

    Rabbers, J.J.; van der Meer, O.; Klein Zeggelink, W.F.A.; ten Haken, Bernard; Chevtchenko, O.A.; ten Kate, Herman H.J.

    1999-01-01

    BSCCO/Ag tape superconductors are used in applications like power cables, transformers and motors/generators. In these applications, the superconductor is exposed to an alternating magnetic field that can have different orientations with respect to the tape. In applications like three-phase power

  11. Measuring transport current loss of BSCCO/Ag tapes exposed to external AC magnetic field

    NARCIS (Netherlands)

    Rabbers, J.J.; ten Haken, Bernard; ten Kate, Herman H.J.

    1998-01-01

    BSCCO/Ag tape superconductors are developed for electrical power applications at liquid nitrogen temperatures. In these applications, e.g., superconducting transformers and power cables, an AC transport current and an AC magnetic field are present at the same time. A set-up to measure the influence

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

    Directory of Open Access Journals (Sweden)

    Erika Maliníková

    2013-05-01

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

  13. Bryophyte Species Richness and Composition along an Altitudinal Gradient in Gongga Mountain, China

    Science.gov (United States)

    Sun, Shou-Qin; Wu, Yan-Hong; Wang, Gen-Xu; Zhou, Jun; Yu, Dong; Bing, Hai-Jian; Luo, Ji

    2013-01-01

    An investigation of terrestrial bryophyte species diversity and community structure along an altitudinal gradient from 2,001 to 4,221 m a.s.l. in Gongga Mountain in Sichuan, China was carried out in June 2010. Factors which might affect bryophyte species composition and diversity, including climate, elevation, slope, depth of litter, vegetation type, soil pH and soil Eh, were examined to understand the altitudinal feature of bryophyte distribution. A total of 14 representative elevations were chosen along an altitudinal gradient, with study sites at each elevation chosen according to habitat type (forests, grasslands) and accessibility. At each elevation, three 100 m × 2 m transects that are 50 m apart were set along the contour line, and three 50 cm × 50 cm quadrats were set along each transect at an interval of 30 m. Species diversity, cover, biomass, and thickness of terrestrial bryophytes were examined. A total of 165 species, including 42 liverworts and 123 mosses, are recorded in Gongga mountain. Ground bryophyte species richness does not show any clear elevation trend. The terrestrial bryophyte cover increases with elevation. The terrestrial bryophyte biomass and thickness display a clear humped relationship with the elevation, with the maximum around 3,758 m. At this altitude, biomass is 700.3 g m−2 and the maximum thickness is 8 cm. Bryophyte distribution is primarily associated with the depth of litter, the air temperature and the precipitation. Further studies are necessary to include other epiphytes types and vascular vegetation in a larger altitudinal range. PMID:23472146

  14. 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...

  15. Non-pollen palynomorphs from surface sediments along an altitudinal transect of the Venezuelan Andes

    OpenAIRE

    Montoya, E.; Rull, V.; van Geel, B.

    2010-01-01

    Palynological studies including records of non-pollen palynomorphs (NPP) are uncommon in the Neotropics, in spite of their demonstrated usefulness in other regions. Modern analog studies to improve palaeoecological interpretations of NPP are even more scarce. Here, we report the NPP assemblages recorded in modern surface samples from an altitudinal transect of the Venezuelan Andes, ranging from about 2300 and 4600 m. We compared the assemblages with the results of previous pollen analyses of ...

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

    Directory of Open Access Journals (Sweden)

    Shou-Qin Sun

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

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

    Directory of Open Access Journals (Sweden)

    Wenxin Zhang

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

  18. 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.

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:25607732

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Altitudinal variation in body size in the Rice Frog (Rana limnocharis in southwestern China

    Directory of Open Access Journals (Sweden)

    Yan Hong Liu

    2012-07-01

    Full Text Available Bergmann’s rule states that, within species of endotherms, individuals tend to be larger in cooler environments, and has been reputed to apply to some ectotherms including amphibians. However, the validity of the rule has been debated, questioning whether Bergmann’s clines are generally present in anurans. In the view, we studied altitudinal variation in body size in the rice frog (Rana limnocharis among populations from Sichuan province located at three altitudes to find if there exist any differences in a relatively small altitudinal range (290-375 m. The results showed that individuals from higher altitudes tended to be larger in body size than lower altitudes, which was consistent with Bergmann’s cline. Moreover, when the effect of age was removed, variation in body size of the frogs across altitudes still remained. Our findings suggested that age affected the pattern of variation in body size across the altitudinal cline, we also discussed that factors other than age also contributed to size differences among populations.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. CORRELATION BETWEEN STRUCTURAL RETINAL NERVE FIBRE LAYER THICKNESS AND FUNCTIONAL VISUAL FIELD LOSS IN PRIMARY OPEN ANGLE GLAUCOMA

    Directory of Open Access Journals (Sweden)

    A. Arun

    2015-04-01

    Full Text Available Background: Glaucoma is characterized by progressive degeneration of retinal ganglion cells and their axons that leads to nerve fiber layer loss, optic disc cupping, and consecutive glaucomatous visual field changes. Study is done in Department of ophthalmology, S.V.R.R Government General Hospital, S.V.Medical College Tirupati. A total of 52 eyes of 29 patients were included in the study. Mean age of the patients included in the study is 64.14+/- 11.43 years. Majority were male patients (68.96%. Female patients were only 31.04%.

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

    Directory of Open Access Journals (Sweden)

    Arvid Odland

    2010-11-01

    Full Text Available The main aim of the present paper was to study regional differences in the altitudinal distribution limits of vascular plants in relation to mountain height and latitudinal position. Altitudinal limits from previously studied areas were compared with the altitudinal distribution limits given by Lid and Lid (2005 as a reference. Based on these comparisons, different trend lines were used to evaluate the effects of mountain height and thereby estimate how high a mountain must be for vascular plants to reach their potential altitudinal limits. Study areas were Hardangervidda and Aurland in southern Norway, Jämtland in central Sweden, Lule Lappmark in northern Sweden, Troms in northern Norway and Graubünden in Switzerland. A regression analysis of the altitudinal limits for 177 vascular plants in Scandinavia compared with the same species in Switzerland gave a highly significant (p 0.422. Comparisons within Scandinavia show that lowland/boreal and high altitudinal species showed different altitudinal distribution patterns. The position of the forest limit increased on average with 72.4 m per degree increase in latitude from Switzerland to northern Scandinavia. The altitudinal span of the alpine zone was approximately 1100 m in Switzerland and in Jotunheimen but considerably lower in the southern Scandinavian study areas. Studies of altitudinal distribution limits of vascular plants may give an indication of to what extent the height of a particular mountain influence plant distribution and thereby its vegetation zonation.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  8. 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...

  9. Density Dependence, Landscape, and Weather Impacts on Aquatic Aedes japonicus japonicus (Diptera: Culicidae) Abundance Along an Urban Altitudinal Gradient.

    Science.gov (United States)

    Chaves, Luis Fernando; Moji, Kazuhiko

    2018-02-28

    The Asian Bush Mosquito, Aedes (Finlaya) japonicus japonicus (Theobald) is an important globally invasive mosquito species. In comparison with other major invasive mosquitoes, relatively little is known about Ae. j. japonicus population dynamics in the field. Here, we present results from a 54-biweek long study of Ae. j. japonicus abundance in ovitraps set across the altitudinal gradient of Mt. Konpira, Nagasaki, Japan. Spatially, we found that Ae. j. japonicus fourth instar larvae (Aj4il) were more abundant at the base and top of Mt. Konpira and in ovitraps with more platykurtic water temperature (WT) distributions. In contrast, we found that temporally Aj4il were more abundant when ovitrap WT was more leptokurtic with 2 weeks of lag, and with high relative humidity SD with 2 months of lag. We also found that Aj4il were unlikely present when ovitrap WT was below 12.41°C. Parameter estimates for the Ricker model suggested that Ae. j. japonicus population growth was under density-dependence regulation, with a stable population dynamics whose fluctuations were associated with changes in ovitrap WT kurtosis and demographic stochasticity. Our results suggest that Aj4il abundance is more sensitive to temperature changes in kurtosis than mean values, potentially limiting the predictive ability of Ae. j. japonicus niche models based on the increase of average temperatures with global warming, and suggesting this mosquito species has a relatively coarse-grained response to temperature changes.

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

    International Nuclear Information System (INIS)

    Peterle, T.J.

    1979-01-01

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

  11. [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.

  12. 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....

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

    Directory of Open Access Journals (Sweden)

    Xiaodong Nie

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

  14. 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

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

    Science.gov (United States)

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

    2009-01-01

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

  16. Altitudinal and seasonal variations of persistent organic pollutants in the Bolivian Andes Mountains.

    Science.gov (United States)

    Estellano, Victor H; Pozo, Karla; Harner, Tom; Franken, Margot; Zaballa, Mauricio

    2008-04-01

    Polyurethane foam disk passive air samplers were deployed over four periods of approximately 3 months along an altitudinal gradient (1820, 2600, 4650, and 5200 masl) on the east side of the Andean mountain range in Bolivia. The purpose of the study was to assess the gas-phase concentration and the altitudinal and seasonal trends of organochlorine pesticides and polychlorinated biphenyls (PCBs). Target compounds that were regularly detected included alpha- and gamma-hexachlorocyclohexane (HCH), endosulfans, and select PCB congeners. Endosulfans and HCH concentrations increased with altitude. Enrichment factors (concentration at the highest altitude divided by concentration at the lowest altitude) ranged from 10 to 20 for HCHs and 3 to 10 for endosulfans. Air parcel back trajectory analysis indicated that, in general, the high-altitude sites were exposed to a larger airshed and hence susceptible to long-range atmospheric transport from more distant regions. Seasonal differences were also observed with SigmaHCH concentrations peaking during periods 2 and 3 (March-September 2005). Airsheds (derived from the analysis of back trajectories) for periods 2 and 3 were less oriented along the Andes range (mountain air) with greater input from coastal regions. Endosulfans peaked during periods 1 and 2 (February-June 2005) and also exhibited the highest air concentrations of the target compounds, reaching approximately 1500 pg/m3 at the two highest elevation sites. PCB air concentrations at all sites were generally typical of global background values (measure air concentrations of persistent organic pollutants (POPs) in Bolivia and one of only a few studies to investigate altitudinal gradients of POPs.

  17. 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

  18. 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

  19. 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

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

    International Nuclear Information System (INIS)

    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

  1. 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

  2. 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

  3. 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

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

    Directory of Open Access Journals (Sweden)

    Ananina Galina

    2004-01-01

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

  5. 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

  6. The Colorado Ultraviolet Transit Experiment (CUTE): a dedicated cubesat mission for the study of 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

    2017-08-01

    The Colorado Ultraviolet Transit Experiment (CUTE) is a near-UV (2550 - 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 > 60 spectroscopic transits of hot Jupiters over a nominal seven 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 ˜ 22 cm2 , low instrumental background, and a spectral resolving power of R ˜ 3000 over the entire science bandpass. These performance characteristics enable CUTE to discern a transit depth of < 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.

  7. 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.

  8. Significant reduction in AC transport self-field losses of Ag-sheathed Bi2223 tapes achieved by changing filament arrangements

    Science.gov (United States)

    Oota, A.; Inada, R.; Inagaki, N.; Ogawa, Y.; Nakamura, Y.; Fukunaga, T.; Zhang, P. X.

    2004-05-01

    Significant reduction in AC transport self-field losses has been achieved at 77 K for Ag-sheathed Bi2223 multifilamentary tapes with m × n (m,n = 3 or 5) filament arrangements, fabricated via a rectangular deformation process using two-axis rollers. This achievement is not effected by introducing resistive barriers but by changing filament arrangements. Despite the main contribution being the hysteresis loss of the superconductor, the loss values are decreased by approximately 50-70%, compared with the values for multifilamentary tapes obtained by a standard powder-in-tube process. More complicated filament arrangements achieved via a rectangular deformation process lead to further reduction in the loss values. On the basis of numerical calculations, the loss reduction is mainly ascribed to a division of the field-free core in the filament groups near the tape edge under AC current transmission. The study should pave the way to removing an obstacle to loss reduction and to developing tape strands with low loss values satisfying practical demands.

  9. Significant reduction in AC transport self-field losses of Ag-sheathed Bi2223 tapes achieved by changing filament arrangements

    International Nuclear Information System (INIS)

    Oota, A; Inada, R; Inagaki, N; Ogawa, Y; Nakamura, Y; Fukunaga, T; Zhang, P X

    2004-01-01

    Significant reduction in AC transport self-field losses has been achieved at 77 K for Ag-sheathed Bi2223 multifilamentary tapes with m x n (m,n = 3 or 5) filament arrangements, fabricated via a rectangular deformation process using two-axis rollers. This achievement is not effected by introducing resistive barriers but by changing filament arrangements. Despite the main contribution being the hysteresis loss of the superconductor, the loss values are decreased by approximately 50-70%, compared with the values for multifilamentary tapes obtained by a standard powder-in-tube process. More complicated filament arrangements achieved via a rectangular deformation process lead to further reduction in the loss values. On the basis of numerical calculations, the loss reduction is mainly ascribed to a division of the field-free core in the filament groups near the tape edge under AC current transmission. The study should pave the way to removing an obstacle to loss reduction and to developing tape strands with low loss values satisfying practical demands

  10. 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

  11. 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

  12. 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

  13. 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

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

    Science.gov (United States)

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

    2012-09-01

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

  15. 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

  16. 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.

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

    Science.gov (United States)

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

    2012-09-15

    In order to explore the influence of site-specific soil properties on nitrogen (N) and phosphorus (P) losses between individual fields and crop sequences, 16 drained fields with clay soils were investigated in a four-year study. Mean total N (TN) loss was 6.6-11.1 from a conventional, 14.3-21.5 from an organic and 13.1-23.9 kg ha(-1) year(-1) from an integrated cropping system across a 4 year period, with 75% in nitrate form (NO(3)-N). Mean total P (TP) loss was 0.96-3.03, 0.99-4.63 and 0.76-2.67 kg ha(-1) year(-1), from the three systems respectively during the same period, with 25% in dissolved reactive form (DRP). Median N efficiency was calculated to be 70% including gains from estimated N fixation. According to principal component factor (PCA) analysis, field characteristics and cropping system were generally more important for losses of N and P than year. Accumulation of soil mineral N in the autumn and (estimated) N fixation was important for N leaching. No P fertilisers were used at the site in either cropping system. Total P concentration in drainage water from each of the fields was marginally significantly (pleguminous crops needs to be considered carefully when designing cropping systems high efficiency in N utilisation and low environmental impact. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. 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.

  19. Indigenous and invasive fruit fly diversity along an altitudinal transect in Eastern Central Tanzania.

    Science.gov (United States)

    Geurts, Katrien; Mwatawala, Maulid; De Meyer, Marc

    2012-01-01

    The relative abundance of indigenous and invasive frugivorous fruit flies (Diptera: Tephritidae) was evaluated spatially and temporally along an altitudinal transect between 581-1650 m in the Uluguru Mountains near Morogoro, Tanzania. The polyphagous invasive fruit fly Bactrocera invadens Drew, Tsuruta, and White and the indigenous fruit fly Ceratitis rosa Karsch show a similar temporal pattern, but are largely separated spatially, with B. invadens being abundant at lower elevation and C. rosa predominant at higher elevation. The polyphagous indigenous C. cosyra (Walker) coincides with B. invadens but shows an inverse temporal pattern. The cucurbit feeders B. cucurbitae (Coquillett) and Dacus bivittatus (Bigot) show a similar temporal pattern, but the former is restricted to lower elevations. Host availability and climatic differences seem to be the determining factors to explain the differences in occurrence and abundance in time and space.

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

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2003-01-01

    was dominated by insects, mainly Ephemeroptera, Trichoptera and Diptera at all three altitudes. Odonata and Hemiptera were relatively rich in lowland streams, scarcely present in the midland streams and absent in the highland streams (as was the case for the less diverse orders Lepidoptera and Megaloptera......Altitudinal patterns in diversity of macroinvertebrate families at different spatial scales (stone, stream and altitude) were studied by collecting stone samples from six streams at each of the three altitudes: lowlands (400m), midlands (2000m) and highlands (3800 m), in the equatorial Andes...... of Ecuador. Stream sites were characterised by a number of physico-chemical parameters and the fauna by several indices of richness, diversity and evenness. A MDS ordination on the composition of the fauna clearly separated the streams in three groups according to altitude. The invertebrate fauna...

  1. 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 migrants, suggest fundamentally different drivers of altitudinal migration.

  2. Kinetics and mechanisms of the loss of water from the cyclohexanol radical ion at times from 50 picoseconds to 10 microseconds following field ionization

    International Nuclear Information System (INIS)

    Derrick, P.J.; Holmes, J.L.; Morgan, R.P.

    1975-01-01

    The rates of loss of water from a series of specifically deuterated cyclohexanols were measured at times as short as 50 psec following field ionization (FI) and at longer times extending to 10 μsec. It is concluded that FI does not induce ring cleavage in the molecular ion prior to water loss. A previously unidentified 1,2 elimination is the fastest process effecting loss of water; loss of water initiated by 1,4-hydrogen transfer is a slower process. It is suggested that, following electron impact (EI) at 70 eV, the more energetic molecular ions undergo rapid ring cleavage to form acyclic isomers, which may delay for up to microseconds before decomposing to eliminate water. (U.S.)

  3. Altitudinal dynamics of glacial lakes under changing climate in the Hindu Kush, Karakoram, and Himalaya ranges

    Science.gov (United States)

    Ashraf, Arshad; Naz, Rozina; Iqbal, Muhammad Bilal

    2017-04-01

    The environmental challenges posed by global warming in the Himalayan region include early and rapid melting of snow and glaciers, creation of new lakes, and expansion of old ones posing a high risk of glacial lakes outburst flood (GLOF) hazard for downstream communities. According to various elevation ranges, 3044 lakes were analyzed basinwide in the Hindu Kush-Karakoram-Himalaya (HKH) ranges of Pakistan using multisensor remote sensing data of the 2001-2013 period. An overall increase in glacial lakes was observed at various altitudinal ranges between 2500 and 5500, m out of which noticeable change by number was within the 4000-4500 m range. The analysis carried out by glacial-fed lakes and nonglacial-fed lakes in different river basins indicated variable patterns depending on the geographic location in the HKH region. The correlation analysis of parameters like lake area, expansion rate, and elevation was performed with 617 glacial lakes distributed in various river basins of the three HKH ranges. Lake area (2013) and elevation showed a negative relationship for all basins except Hunza, Shigar, and Shyok. The correlation between the expansion rate of lakes and elevation was on the positive side for Swat, Gilgit, Shigar, and Shingo basins-a situation that may be attributed to the variable altitudinal pattern of temperature and precipitation. In order to explore such diverse patterns of lake behavior and relationship with influential factors in the HKH, detailed studies based on using high resolution image data coupled with in situ information are a prerequisite. Although an increase in lake area observed below 3500 m would be favorable for water resource management, but could be alarming in context of glacial flood hazards that need to be monitored critically on a long-term basis.

  4. 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

  5. Fast phosphorus loss by sediment resuspension in a re-established shallow lake on former agricultural fields

    DEFF Research Database (Denmark)

    Kragh, Theis; Sand-Jensen, Kaj; Petersen, Kathrine

    2017-01-01

    in future lake restorations on former agricultural land by facilitating fast and profound sediment P loss lowering subsequent internal loading in the following years. Keeping the water level low during the earliest phases could increase P loss by enhancing both sediment resuspension and hydraulic flushing....... and P contents. This enabled estimate of the loss of sediment P with high spatial resolution by comparison with the initial homogeneous P content in the soils. The approach was advantageous as P pools were highly heterogeneously distributed depending on water depth and wave exposure. We found that 65...

  6. 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.

  7. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-04-01

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

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

    Science.gov (United States)

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

    2015-01-01

    In this data paper, we describe the dataset of the Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains (MIGRAME) project, which aims to assess the capacity of altitudinal migration and colonization of marginal habitats by Quercus pyrenaica Willd. forests in Sierra Nevada (southern Spain) considering two global-change drivers: temperature increase and land-use changes. The dataset includes information of the forest structure (diameter size, tree height, and abundance) of the Quercus pyrenaica ecosystem in Sierra Nevada obtained from 199 transects sampled at the treeline ecotone, mature forest, and marginal habitats (abandoned cropland and pine plantations). A total of 3839 occurrence records were collected and 5751 measurements recorded. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this mountain range.

  10. 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.

  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. 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

  13. Homogeneous genetic structure and variation in tree architecture of Larix kaempferi along altitudinal gradients on Mt. Fuji.

    Science.gov (United States)

    Nishimura, Masao; Setoguchi, Hiroaki

    2011-03-01

    Variations in tree architecture and in the genetic structure of Larix kaempferi on Mt. Fuji were surveyed along altitudinal gradients using 11 nSSR loci. In total, 249 individuals from six populations along three trails at altitudes ranging from approximately 1,300 to 2,700 m were investigated. Gradual changes in tree architecture with increasing elevation, from erect trees to flag trees and krummholz mats, were observed in the high-altitude populations (> 2,000 m) on all trails. These findings suggest that tree architecture is correlated with the severe environmental conditions associated with increasing elevation, such as strong winds. In contrast to obvious variations in tree architecture, the genetic diversity of populations along the trails was almost uniform (H (E) = 0.717-0.762) across the altitudinal range. The results of the AMOVA and STRUCTURE analyses, and the analysis for isolation by distance pattern, suggest homogeneous genetic structuring across all populations on Mt. Fuji, while the pairwise F (ST) showed barriers to gene flow between altitudinal populations that were demarcated as high- or low-altitude populations by Abies-Tsuga forest. Although the evergreen coniferous forests on the mountainside may hinder gene flow, this may be explained by the long-distance seed dispersal of the Japanese larch and/or a short population history resulting from eruptions or slush avalanches, although evergreen coniferous forests on the mountainside may hinder gene flow.

  14. 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.

  15. 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

    2016-02-29

    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 ((14)C-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.

  16. 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.

  17. Field Transmission of 8 × 170 Gb/s Over High-Loss SSMF Link Using Third-Order Distributed Raman Amplification

    Science.gov (United States)

    Schneiders, Malte; Vorbeck, Sascha; Leppla, Ralph; Lach, Eugen; Schmidt, Michael; Papernyi, Serguei B.; Sanapi, Kris

    2006-01-01

    This paper reports on the field transmission of N × 170-Gb/s over high-loss fiber links using third-order distributed Raman amplification (DRA) in a commercially operated network of Deutsche Telekom. It gives an overview of the key technologies applied for the realization of an 8 × 170 Gb/s (1.28 Tb/s) dense wavelength division multiplexing (DWDM) system demonstrator and summarizes long-haul transmission experiments with terabit-per-second capacity over European fiber infrastructure. Third-order DRA enabled repeaterless transmission of 1 × 170 Gb/s and 8 × 170 Gb/s over links of 185-and 140-km field fiber, respectively. Including an additional 25 km of lumped standard single-mode fiber (SSMF) at the end of the span, a total loss of 61 and 44 dB, respectively, was bridged.

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

    Directory of Open Access Journals (Sweden)

    Astrup Arne

    2011-02-01

    Full Text Available Abstract Background 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. Methods In this study we hypothesize that imaging variables assessed with radiographs and MRI scans pre-treatment can predict the symptomatic changes following a recommended clinically significant weight reduction Patients were recruited from the Department of Rheumatology, Frederiksberg Hospital, Denmark. Eligibility criteria were: age >18 years; primary osteoarthritis according to ACR; BMI > 28 kg/m2; motivation for weight loss. Subjects were randomly assigned to either intervention by low-energy diet (LED for 8 weeks followed by another 24 weeks of dietary instruction or control-group. MRI scans and radiographs were scored for structural changes and these parameters were examined as independent predictors of changes in osteoarthritis symptoms after 32 weeks. The outcome assessor and statistician were blinded to group allocation. Results No significant correlations were found between imaging variables and changes in Western Ontario and McMaster Universities Index of Osteoarthritis (Spearman's test, r 0.07. Only the LED group achieved a weight loss, with a mean difference of 16.3 kg (95%CI: 13.4-19.2;P Conclusion Stage of joint destruction, assessed on either radiographs or low-field MRI (0.2T, does not preclude a symptoms relief following a clinically relevant weight loss in elderly obese female patients with knee osteoarthritis.

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

    OpenAIRE

    Roy Choudhury, Raja; Roy Choudhury, Arundhati; Kanti Ghose, Mrinal

    2013-01-01

    A faster and accurate semianalytical formulation with a robust optimization solution for estimating the splice loss of graded-index fibers has been proposed. The semianalytical optimization of modal parameters has been carried out by Nelder-Mead method of nonlinear unconstrained minimization suitable for functions which are uncertain, noisy, or even discontinuous. Instead of normally used Gaussian function, as the trial field for the fundamental mode of graded-index optical fiber a novel sinc...

  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. 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.

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

    Science.gov (United States)

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

    2012-01-01

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

  3. Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients.

    Science.gov (United States)

    Blake, Stephen; Yackulic, Charles B; Cabrera, Fredy; Tapia, Washington; Gibbs, James P; Kümmeth, Franz; Wikelski, Martin

    2013-03-01

    Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear. A relatively simple, tractable system - giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long-distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns? We recorded the daily locations of 17 GPS-tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality. Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non-migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid-sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid-sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked. Giant tortoises are

  4. Altitudinal population structure and microevolution of the malaria vector Anopheles cruzii (Diptera: Culicidae).

    Science.gov (United States)

    Lorenz, Camila; Marques, Tatiani Cristina; Sallum, Maria Anice Mureb; Suesdek, Lincoln

    2014-12-16

    In Brazil, the autochthonous transmission of extra-Amazonian malaria occurs mainly in areas of the southeastern coastal Atlantic Forest, where Anopheles cruzii is the primary vector. In these locations, the population density of the mosquito varies with altitude (5-263 m above sea level), prompting us to hypothesise that gene flow is also unevenly distributed. Describing the micro-geographical and temporal biological variability of this species may be a key to understanding the dispersion of malaria in the region. We explored the homogeneity of the An. cruzii population across its altitudinal range of distribution using wing shape and mtDNA gene analysis. We also assessed the stability of wing geometry over time. Larvae were sampled from lowland (5-20 m) and hilltop (81-263 m) areas in a primary Atlantic Forest region, in the municipality of Cananéia (State of São Paulo, Brazil). The right wings of males and females were analysed by standard geometric morphometrics. Eighteen landmarks were digitised for each individual and a discriminant analysis was used to compare samples from the hilltop and lowland. A 400-bp DNA fragment of the mitochondrial cytochrome oxidase gene subunit I (CO-I) was PCR-amplified and sequenced. Wing shapes were distinct between lowland and hilltop population samples. Results of cross-validated tests based on Mahalanobis distances showed that the individuals from both micro-environments were correctly reclassified in a range of 54-96%. The wings of hilltop individuals were larger. The CO-I gene was highly polymorphic (haplotypic diversity = 0.98) and altitudinally structured (Фst = 0.085 and Jaccard = 0.033). We found 60 different haplotypes but only two were shared by the lowland and hilltop populations. Wing shape changed over the brief study period (2009-2013). Wing geometry and CO-I gene analysis indicated that An. cruzii is vertically structured. Wing shape varied rapidly, but altitude structure was maintained. Future

  5. 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.

  6. 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.

  7. 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

  8. Investigation of some locally water-soluble natural polymers as circulation loss control agents during oil fields drilling

    Directory of Open Access Journals (Sweden)

    A.M. Alsabagh

    2014-03-01

    Full Text Available Eliminating or controlling lost circulation during drilling process is costly and time-consuming. Polymers play an important role in mud loss control for their viscosity due to their high molecular weight. In this paper, three natural cellulosic polymers (carboxymethyl cellulose, guar gum and potato starch were investigated as lost circulation control material by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API standard. The experiments were conducted in a permeability plugging apparatus (PPA at a differential pressure of 100 and 300 psi, using 10, 60 and 90 ceramic discs. From the obtained data, it was found that the 0.1% from the carboxymethyl cellulose exhibited the best results in the filtration parameters among 0.3% guar gum and 0.6% potato starch. At the same time the carboxymethyl cellulose (CMC enhanced the rheological properties of the drilling mud better than the two other used natural polymers in the term of gel strength, thixotropy, plastic and apparent viscosity. These results were discussed in the light of the adsorption and micellar formation.

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

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Brodersen, Klaus Peter

    2008-01-01

    1. We measured respiration of the larvae of aquatic insects from streams in the Ecuadorian Andes in relation to oxygen saturation at 5, 8, 11, 14 and 17 °C. Polycentropus (Polycentropodidae), Lachlania (Oligoneuriidae), Anchytarsus (Ptilodactylidae) and Anacroneuria (Perlidae) represented genera ...... 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....... points on respiration versus oxygen curves and by the effect of temperature on the ability to oxy-regulate. 2. For all six genera, respiration was affected by oxygen saturation and temperature. Respiration (mg O2 g-1 AFDM h-1) at 70% oxygen saturation (Michaelis-Menten fitted) varied from 2.6 to 7...... "low-altitude" genera. 3. The oxy-regulatory capacity (critical points and initial decrease in respiration versus oxygen regressions) varied among genera and was affected by temperature. Lachlania, Claudioperla and Anomalocosmoecus had a higher ability to oxy-regulate at low than at high temperatures...

  10. 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.

  11. Population dynamics of Armigeres subalbatus (Diptera: Culicidae) across a temperate altitudinal gradient.

    Science.gov (United States)

    Chaves, L F; Imanishi, N; Hoshi, T

    2015-10-01

    Understanding the impacts of weather fluctuations, and environmental gradients, on the abundance of vectors is fundamental to grasp the dynamic nature of the entomological risk for disease transmission. The mosquito Armigeres subalbatus (Coquillet) is a common vector of filariasis. Nevertheless, its population dynamics have been relatively poorly studied. Here, we present results from a season long study where we studied spatio-temporal abundance patterns of Ar. subalbatus across the altitudinal gradient of Mt. Konpira in Nagasaki, Japan. Spatially, we found that abundance of adult Ar. subalbatus decreased with altitude and increased in areas where the ground was rich in leaf litter. Similarly, adult activity was observed only when relative humidity was over 65%. Temporally, we found that peaks in abundance followed large rainfall events. Nevertheless, this mosquito was under significant density dependence regulation. Our results suggest that Ar. subalbatus population peaks following large rainfall events could reflect the recruitment of individuals that were dormant as dry eggs. We did not find a clear signal of temperature on abundance changes of this mosquito, but only on its phenology. Since ground cover seemed more critical than temperature to its spatial distribution, we propose that this mosquito might have some degree of autonomy to changes in temperature.

  12. The distribution of mosquitoes across an altitudinal gradient in the Galapagos Islands.

    Science.gov (United States)

    Asigau, Samoa; Hartman, Daniel A; Higashiguchi, Jenni M; Parker, Patricia G

    2017-12-01

    An avian malaria parasite (genus Plasmodium) has been detected consistently in the Galapagos Penguin (Spheniscus mendiculus) and less frequently in some passerines. We sampled three resident mosquito species (Aedes taeniorhynchus, Culex quinquefasciatus, and Aedes aegypti) using CDC light and gravid traps on three islands in 2012, 2013, and 2014. We sampled along altitudinal gradients to ask whether there are mosquito-free refugia at higher elevations as there are in Hawaii. We captured both Ae. taeniorhynchus and Cx. quinquefasciatus at all sites. However, abundances differed across islands and years and declined significantly with elevation. Aedes aegypti were scarce and limited to areas of human inhabitation. These results were corroborated by two negative binomial regression models which found altitude, year, trap type, and island as categorized by human inhabitation to be significant factors influencing the distributions of both Ae. taeniorhynchus and Cx. quinquefasciatus. Annual differences at the highest altitudes in Isabela and Santa Cruz indicate the lack of a stable highland refuge if either species is found to be a major vector of a parasite, such as avian malaria in Galapagos. Further work is needed to confirm the vector potential of both species to understand the disease dynamics of avian malaria in Galapagos. © 2017 The Society for Vector Ecology.

  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. Distribution of tabanids (Diptera: Tabanidae) along a two-sided altitudinal transect.

    Science.gov (United States)

    Hackenberger, Branimir K; Jarić, Davorka; Krcmar, Stjepan

    2009-12-01

    The pattern of horse fly (Diptera: Tabanidae) distribution and correlations among biodiversity, abundance, abiotic factors, and altitude were determined along a two-sided altitudinal transect. The sampling was carried out on five 3-d periods during tabanid seasonal activity. Linen canopy traps with 1-octen-3-ol as an attractant were used at 20 sampling sites along the transect. The results showed that the qualitative composition of tabanid species can be distinguished by altitude and, especially, between southeastern and northwestern mountain slopes. The peaks of horse fly species richness and abundance were indicated at middle elevations of both slopes, where horse fly distributional groups were overlapping and most rare and infrequent species were sampled. All expected species were sampled according to species accumulation curve. The canonical correlation analysis separated species and sampling sites into three clusters; two were positively correlated with the temperature and the wind but differed in sensitivity toward them, and the third cluster was correlated with the humidity. The horse fly distribution was nonhomogenous, and the distributional patterns were only partially determined by altitude and vegetation. The determining environmental variables were different for each slope: temperature and wind for the southern slope (Mediterranean climatic zone) and humidity for the northern slope (continental climatic zone).

  15. 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.

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

    Science.gov (United States)

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

    2015-12-01

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

  17. Estimation of potential loss of two pesticides in runoff in Fillmore County, Minnesota using a field-scale process-based model and a geographic information system

    Science.gov (United States)

    Capel, P.D.; Zhang, H.

    2000-01-01

    In assessing the occurrence, behavior, and effects of agricultural chemicals in surface water, the scales of study (i.e., watershed, county, state, and regional areas) are usually much larger than the scale of agricultural fields, where much of the understanding of processes has been developed. Field-scale areas are characterized by relatively homogeneous conditions. The combination of process-based simulation models and geographic information system technology can be used to help extend our understanding of field processes to water-quality concerns at larger scales. To demonstrate this, the model "Groundwater Loading Effects of Agricultural Management Systems" was used to estimate the potential loss of two pesticides (atrazine and permethrin) in runoff to surface water in Fillmore County in southeastern Minnesota. The county was divided into field-scale areas on the basis of a 100 m by 100 m grid, and the influences of soil type and surface topography on the potential losses of the two pesticides in runoff was evaluated for each individual grid cell. The results could be used for guidance for agricultural management and regulatory decisions, for planning environmental monitoring programs, and as an educational tool for the public.

  18. Study of ac loss in Bi-2223/Ag tape under the simultaneous action of ac transport current and ac magnetic field shifted in phase

    International Nuclear Information System (INIS)

    Vojenciak, M; Souc, J; Ceballos, J M; Goemoery, F; Klincok, B; Pardo, E; Grilli, F

    2006-01-01

    Investigation of ac loss under the simultaneous action of the transport ac current and the external ac magnetic field is of prime importance for the reliable prediction of dissipation in electric power devices such as motors/generators, transformers and transmission cables. An experimental rig allowing us to perform ac loss measurements in such conditions, on short (10 cm) tape samples of high-temperature superconductor Bi-2223/Ag, was designed and tested. Both the electromagnetic and thermal methods were incorporated, allowing us to combine the better sensitivity of the former and the higher reliability of the latter. Our main aim was to see how the ac loss depends on the phase shift between the transport current and the external magnetic field. Such a shift could have different values in various applications. While in a transformer winding, the maximum phase shift at full load will probably not exceed a few degrees, in a three phase transmission cable in tri-axial configuration it is around 120 0 . Therefore, we explored the whole range of phase shifts from 0 to 360 0 . Surprisingly, the maxima of dissipation did not coincide with zero shift as expected from qualitative considerations

  19. 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

  20. Transport current loss of BSCCO/Ag tape in different orientations of the external alteranting magnetic field

    NARCIS (Netherlands)

    Rabbers, J.J.; ten Haken, Bernard; ten Kate, Herman H.J.

    1999-01-01

    BSCCO/Ag tapes are being developed for electrical power applications at liquid nitrogen temperatures. In these applications, conductors are exposed to an alternating magnetic field and fed simultaneously with an alternating transport current. In this contribution the influence of an external

  1. Evaluating the potential nitrogen savings without yield loss using variable nitrogen application strategies in a heterogeneous winter wheat field

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Nyholm; Sørensen, Claus Aage Grøn; Søgaard, Henning Tangen

    During a single growth season, a plot trial was carried out in a selected heterogeneous field in Denmark in an attempt to estimate the optimal variable nitrogen rate applied to winter wheat. 61 Nitrogen/grain yield dose–response curves were estimated using five nitrogen application rates (30, 90,...

  2. 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.

  3. 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.

  4. Loss Networks

    OpenAIRE

    Kelly, F. P.

    1991-01-01

    This paper describes work on the stochastic modelling of loss networks. Such systems have long been of interest to telephone engineers and are becoming increasingly important as models of computer and information systems. Throughout the century problems from this field have provided an impetus to the development of probability theory, pure and applied. This paper provides an introduction to the area and a review of recent work.

  5. Loss of interstitial cells of Cajal after pulsating electromagnetic field (PEMF) in gastrointestinal tract of the rats.

    Science.gov (United States)

    Kaszuba-Zwoińska, J; Gil, K; Ziomber, A; Zaraska, W; Pawlicki, R; Królczyk, G; Matyja, A; Thor, P J

    2005-09-01

    Exposure to the magnetic field has remarkably increased lately due to fast urbanization and widely available magnetic field in diagnosis and treatment. However, biological effects of the magnetic field are not well recognized. The myoelectric activity recorded from the gastrointestinal and urinary systems is generated by specialized electrically active cells called interstitial cells of Cajal (ICCs). Thus it seems rational that ICC have significant vulnerability to physical factors like an electromagnetic field. The aim of this study was to evaluate the influence of pulsating electromagnetic field (PEMF) (frequency 10 kHz, 30ms, 300 muT burst, with frequency 1Hz) on ICCs density in the rat gastrointestinal tract. Rats were divided into two groups (n=32). The first group was exposed to PEMF continuously for 1, 2, 3, and 4 weeks (n = 16), and the second group (n=16) served as a control. Tissue samples of the rat stomach, duodenum and proximal colon were fixed and paraffin embedded. The tangential sections of 5 microm thickness were stained immunohistochemically with anti-c-Kit (sc-168) antibody and visualized finally by DAB as chromogen (brown end product). C-Kit positive branched ICC-like cells were detected under the light microscope, distinguished from the c-kit-negative non-branched smooth muscle cells and from the c-kit positive but non-branched mast cells and quantitatively analyzed by MultiScan computer program. Apoptosis detection was performed with rabbit anti-Bax polyclonal antibody (Calbiochem, Germany) and LSAB 2 visualization system. The surface of c-Kit immunopositive cells decreased after exposure to PEMF in each part of the gastrointestinal tract. Reduced density of ICCs was related to exposure time. The most sensitive to PEMF were ICCs in the fundus of the stomach and in the duodenum, less sensitive were ICCs in the colon and pacemaker areas of the stomach. No marked changes in ICC density in the pyloric part of the stomach were observed. We

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

    Directory of Open Access Journals (Sweden)

    Daniel Escoriza

    2014-06-01

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

  7. Potential impacts of climate change on stable flies, investigated along an altitudinal gradient.

    Science.gov (United States)

    Gilles, J; David, J-F; Duvallet, G; Tillard, E

    2008-03-01

    Adult populations of stable flies were sampled along an altitudinal transect in Reunion Island to determine whether higher temperatures were associated with: (a) higher numbers of flies; (b) a longer season of infestation, and/or (c) different responses to warming in the cosmopolitan Stomoxys calcitrans (L) and the tropical Stomoxys niger niger Macquart (Diptera: Muscidae). Flies of both species were trapped at seven farms situated at four altitudes (100-1600 m a.s.l.) over a 90-week period. For both species, there were no relationships between the maximum or mean fly abundance and altitude. Only minimum abundance in winter was significantly higher at lower altitudes. Maximum and mean abundances differed significantly between nearby farms under similar climatic conditions. Seasonal fluctuations in fly abundance changed along the gradient. At lower altitudes, population growth started earlier after the winter but abundance declined earlier in summer, which resulted in a shift of the season of infestation. Seasonal fluctuations of both species were strongly related to climate variables at high altitude, mainly temperature. However, climate variables explained a decreasing proportion of the variations in abundance at lower altitudes. Stomoxys calcitrans was the most abundant species overall, but the proportion of S. n. niger increased significantly at lower altitudes and this species became predominant at 100 m a.s.l. It is concluded that stable fly infestations are unlikely to worsen in response to global warming. Maximum abundance is limited by local factors, possibly larval resources, which suggests that adequate husbandry practices could override the impact of climate change. Because S. n. niger tends to be the predominant pest at elevated temperatures, it is recommended that this species should not be introduced in areas where climate is changing.

  8. 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

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Gene Regulatory Variation Mediates Flowering Responses to Vernalization along an Altitudinal Gradient in Arabidopsis1[W][OPEN

    Science.gov (United States)

    Suter, Léonie; Rüegg, Marlene; Zemp, Niklaus

    2014-01-01

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

  16. 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.

  17. Reduction of soil erosion and mercury losses in agroforestry systems compared to forests and cultivated fields in the Brazilian Amazon.

    Science.gov (United States)

    Béliveau, Annie; Lucotte, Marc; Davidson, Robert; Paquet, Serge; Mertens, Frédéric; Passos, Carlos J; Romana, Christine A

    2017-12-01

    In addition to causing physical degradation and nutrient depletion, erosion of cultivated soils in the Amazon affects aquatic ecosystems through the release of natural soil mercury (Hg) towards lakes and rivers. While traditional agriculture is generally cited as being among the main causes of soil erosion, agroforestry practices are increasingly appreciated for soil conservation. This study was carried out in family farms of the rural Tapajós region (Brazil) and aimed at evaluating soil erosion and associated Hg release for three land uses. Soils, runoff water and eroded sediments were collected at three sites representing a land cover gradient: a recently burnt short-cycle cropping system (SCC), a 2-year-old agroforestry system (AFS) and a mature forest (F). At each site, two PVC soil erosion plots (each composed of three 2 × 5 m isolated subplots) were implemented on steep and moderate slopes respectively. Sampling was done after each of the 20 rain events that occurred during a 1-month study period, in the peak of the 2011 rain season. Runoff volume and rate, as well as eroded soil particles with their Hg and cation concentrations were determined. Total Hg and cation losses were then calculated for each subplot. Erosion processes were dominated by land use type over rainfall or soil slope. Eroded soil particles, as well as the amount of Hg and cations (CaMgK) mobilized at the AFS site were similar to those at the F site, but significantly lower than those at the SCC site (p Erosion reduction at the AFS site was mainly attributed to the ground cover plants characterizing the recently established system. Moreover, edaphic change throughout AFS and F soil profiles differed from the SCC site. At the latter site, losses of fine particles and Hg were enhanced towards soil surface, while they were less pronounced at the other sites. This study shows that agroforestry systems, even in their early stages of implementation, are characterized by low erosion levels

  18. Automatic method of analysis of OCT images in assessing the severity degree of glaucoma and the visual field loss.

    Science.gov (United States)

    Koprowski, Robert; Rzendkowski, Marek; Wróbel, Zygmunt

    2014-02-14

    In many practical aspects of ophthalmology, it is necessary to assess the severity degree of glaucoma in cases where, for various reasons, it is impossible to perform a visual field test - static perimetry. These are cases in which the visual field test result is not reliable, e.g. advanced AMD (Age-related Macular Degeneration). In these cases, there is a need to determine the severity of glaucoma, mainly on the basis of optic nerve head (ONH) and retinal nerve fibre layer (RNFL) structure. OCT is one of the diagnostic methods capable of analysing changes in both, ONH and RNFL in glaucoma. OCT images of the eye fundus of 55 patients (110 eyes) were obtained from the SOCT Copernicus (Optopol Tech. SA, Zawiercie, Poland). The authors proposed a new method for automatic determination of the RNFL (retinal nerve fibre layer) and other parameters using: mathematical morphology and profiled segmentation based on morphometric information of the eye fundus. A quantitative ratio of the quality of the optic disk and RNFL - BGA (biomorphological glaucoma advancement) was also proposed. The obtained results were compared with the results obtained from a static perimeter. Correlations between the known parameters of the optic disk as well as those suggested by the authors and the results obtained from static perimetry were calculated. The result of correlation with the static perimetry was 0.78 for the existing methods of image analysis and 0.86 for the proposed method. Practical usefulness of the proposed ratio BGA and the impact of the three most important features on the result were assessed. The following results of correlation for the three proposed classes were obtained: cup/disk diameter 0.84, disk diameter 0.97 and the RNFL 1.0. Thus, analysis of the supposed visual field result in the case of glaucoma is possible based only on OCT images of the eye fundus. The calculations and analyses performed with the proposed algorithm and BGA ratio confirm that it is possible to

  19. Fast phosphorus loss by sediment resuspension in a re-established shallow lake on former agricultural fields

    DEFF Research Database (Denmark)

    Kragh, Theis; Sand-Jensen, Kaj; Petersen, Kathrine

    2017-01-01

    Lake restoration on fertilized agricultural fields can lead to extensive nutrient release from flooded soils which can maintain a poor ecological quality in the new lake. The period with high sediment release is poorly understood due to few detailed lake restorations studies. We conducted...... was much shorter (40 days) than during summer (92 days). Phosphorus concentrations in the water were closely related to wind speed which caused resuspension of P-containing sediment particles particularly from shallow areas. The excess stream output relative to stream input from May 2013 to November 2015...

  20. 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

    of exactly paired plots in space with seedlings reflecting a response to the studied warm period (1986-2006) and adults reflecting a response to a former and cooler period. For 13 out of 17 species, records of the mean altitude of presence at the seedling life stage are higher than that at the adult life...... higher altitudinal distribution at the seedling life stage in comparison to the adult one suggests a main driver of change highly related to elevation, such as climate warming that occurs during the studied period. Other drivers of change that could play an important role across elevation or act at more...

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    Arash Sahraie

    2016-01-01

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

  3. Minimum cuticular conductance and cuticle features of Picea abies and Pinus cembra needles along an altitudinal gradient in the Dolomites (NE Italian Alps).

    Science.gov (United States)

    Anfodillo, Tommaso; Pasqua di Bisceglie, D; Urso, T

    2002-05-01

    Winter desiccation is believed to contribute to stress in coniferous trees growing at the treeline because cuticular conductance increases with altitude. To test whether winter desiccation occurs in high-altitude conifers of the Dolomites (NE Italian Alps), we measured minimum cuticular conductance (g(min)), needle wettability (contact angle) and cuticle thickness in Picea abies (L.) Karst. and Pinus cembra L. needles from December to August. Samples were collected from adult trees along an altitudinal gradient from valley bottom (1050 m a.s.l.) to the treeline (2170 m a.s.l.). The treeline site is one of the highest in the area and is characterized by a generally low wind exposure. Altitude had no effect on g(min) in either species. In P. abies, large seasonal variations in g(min) were recorded but no changes were related to needle age class. Pinus cembra had a low g(min) and appeared to be efficient in reducing needle water losses. There was a significant increase in g(min) with needle aging in P. cembra growing at low altitude that could be related to a shorter needle longevity compared with P. abies. High contact angles (> 110-120 ) suggested the presence of tubular epicuticular waxes on needles of both species. Contact angles were higher (low wettability) in high-altitude needles than in low-altitude needles. By the end of winter, there was no difference in contact angles between needles in the windward and leeward positions. Wax structures transformed toward planar shapes as demonstrated by the decrease in contact angle from winter to summer. In both species, the cuticle was thicker in needles of high-altitude trees than in needles of low-altitude trees and there was no correlation between g(min) and cuticle thickness. Because desiccation resistance did not decrease with altitude in either species, we conclude that they are not susceptible to winter desiccation at the tree line.

  4. Monte Carlo studies of the radiation fields in the linac coherent light source undulators and of the corresponding signals in the Cerenkov beam loss monitors

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  5. Phenology and species determine growing-season albedo increase at the altitudinal limit of shrub growth in the sub-Arctic.

    Science.gov (United States)

    Williamson, Scott N; Barrio, Isabel C; Hik, David S; Gamon, John A

    2016-11-01

    Arctic warming is resulting in reduced snow cover and increased shrub growth, both of which have been associated with altered land surface-atmospheric feedback processes involving sensible heat flux, ground heat flux and biogeochemical cycling. Using field measurements, we show that two common Arctic shrub species (Betula glandulosa and Salix pulchra), which are largely responsible for shrub encroachment in tundra, differed markedly in albedo and that albedo of both species increased as growing season progressed when measured at their altitudinal limit. A moveable apparatus was used to repeatedly measure albedo at six precise spots during the summer of 2012, and resampled in 2013. Contrary to the generally accepted view of shrub-covered areas having low albedo in tundra, full-canopy prostrate B. glandulosa had almost the highest albedo of all surfaces measured during the peak of the growing season. The higher midsummer albedo is also evident in localized MODIS albedo aggregated from 2000 to 2013, which displays a similar increase in growing-season albedo. Using our field measurements, we show the ensemble summer increase in tundra albedo counteracts the generalized effect of earlier spring snow melt on surface energy balance by approximately 40%. This summer increase in albedo, when viewed in absolute values, is as large as the difference between the forest and tundra transition. These results indicate that near future (albedo related to Arctic vegetation change are unlikely to be particularly large and might constitute a negative feedback to climate warming in certain circumstances. Future efforts to calculate energy budgets and a sensible heating feedback in the Arctic will require more detailed information about the relative abundance of different ground cover types, particularly shrub species and their respective growth forms and phenology. © 2016 John Wiley & Sons Ltd.

  6. ALTITUDINAL DISTRIBUTION OF ASTERACEAE INVADERS, AUSTROEUPATORIUM INULIFOLIUM AND AGERATINA RIPARIA, IN THE DISTURBED FOREST OF BATUKAHU NATURE RESERVE, BALI

    Directory of Open Access Journals (Sweden)

    Laily Mukaromah

    2016-12-01

    Full Text Available Biological invasions are a major threat to biodiversity worldwide. Here, we aim to assess the occurrence of two invasive Asteraceae, Austroeupatorium inulifolium and Ageratina riparia, and the extent of their distributional range along altitudinal gradients in Mt Pohen, Batukahu Nature Reserve, Bedugul, Bali. The cover abundance of Austroeupatorium inulifolium and Ageratina riparia were measured by establishing 92 plot samples in four different forest conditions encompassed elevational ranges from the lowest (forest borders to the highest elevation of Mt Pohen. Results showed that the abundance of both Asteraceae invaders were strongly correlated with disturbed habitats located at lower elevation. The forest borders at these forest sites were characterized by dense thicket of Austroeupatorium inulifolium and high abundance of Ageratina riparia. Both Asteraceae invaders reach their maximum altitudinal range up to the highest peak of the Mt Pohen. Results highlight that high abundance of these Asteraceae invaders which forms dense cover may lead to major forces of change in plant communities and forest ecosystem.

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

  9. 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.

  10. 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

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

    DEFF Research Database (Denmark)

    Jacobsen, Dean

    2008-01-01

    The objective of this study was to explore the altitudinal decrease in local richness of stream macroinvertebrates. I compared the explicatory power of a mid-domain effect (MDE) null model and a number of selected contemporary ecological variables, with a special emphasis on the altitude-mediated......The objective of this study was to explore the altitudinal decrease in local richness of stream macroinvertebrates. I compared the explicatory power of a mid-domain effect (MDE) null model and a number of selected contemporary ecological variables, with a special emphasis on the altitude......-mediated decrease in temperature and oxygen availability as possible driving factors for the observed pattern. Benthic macroinvertebrates were sampled at 30 stream sites between 2,600 and 4,000 m a.s.l. in northern Ecuador. All four measures of local richness (total number of taxa, taxa in Surber samples, Fisher...... with increasing altitude is mainly caused by a decrease in oxygen saturation rather than by a decrease in temperature. Levels of oxygen saturation such as those found at high altitudes do not appear to be lethal to any species, but could affect macroinvertebrates through long-term, sub-lethal effects. I suggest...

  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. 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

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

    Directory of Open Access Journals (Sweden)

    Beniak Michal

    2015-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Raja Roy Choudhury

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nathaniel A. Lyngwi

    2013-03-01

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

  17. Species diversity and life-form patterns in steppe vegetation along a 3000 m altitudinal gradient in the Alborz Mountains, Iran

    NARCIS (Netherlands)

    Mahdavi, Parastoo; Akhani, Hossein; Van der Maarel, Eddy

    Biodiversity pattern and life-form spectra were studied along a 3,000 m altitudinal gradient from a semi-desert area to the alpine peak of Tochal Mountain. The gradient is located on the southern slopes of Central Alborz with a Mediterranean continental climate. DCA ordination was applied to 1,069

  18. 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

  19. Hearing loss

    Science.gov (United States)

    Decreased hearing; Deafness; Loss of hearing; Conductive hearing loss; Sensorineural hearing loss; Presbycusis ... Conductive hearing loss (CHL) occurs because of a mechanical problem in the outer or middle ear. This may be ...

  20. 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.

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

    Science.gov (United States)

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

    2005-12-01

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

  2. Morphological variation of Puntius bimaculatus (Cyprinidae with respect to altitudinal differences and five major river basins of Sri Lanka

    Directory of Open Access Journals (Sweden)

    M.P.K.S.K. De Silva

    2014-09-01

    Full Text Available Forty sites located in five major river basins (Mahaweli, Kelani, Kalu, Gin, and Nilwala at four different altitude ranges (0-150 m, 151-300 m, 301-600 m and 601-1200 m were sampled to study the distribution and intra-specific morphological variation among the endemic fish species Puntius bimaculatus populations in Sri Lanka. Twenty one (21 morphometric characters and 15 meristic characters were recorded with respect to each specimen. Size adjusted meristic data and non transformed meristic data were analysed. In addition, fourteen physico-chemical parameters were recorded from each site. Puntius bimaculatus was found only at 10 locations. Out of the total of 63 individuals 57% were collected from the highest elevation. Twelve meristic and 14 morphometric characters of fish were significantly different among the five rivers. Ten meristic and morphometric characters were significantly differed among altitudinal ranges. Discriminant function analysis resulted three discriminant functions for morphometric characters explained 74.8%, 16.4%, 8.8% variance of the data set. They classified the originally grouped cases (according to the altitudinal range with an accuracy of 87%. Length of the caudal fin, maximum depth of the fish and the position and length of the dorsal fin highly contributed in discrimination of fish into their respective altitude ranges. Meristic characters also resulted in three discriminant functions and explained the variance of 62.3%, 30.9% and 6.8%. They classified originally grouped cases with a 100% accuracy showing that meristic characters are powerful in discriminating the fish. Rays in the ventral, pelvic, caudal and anal fins, and number of scales on lateral line, number of pre and post dorsal scales were the major meristic characters contributed to the discrimination of fish. Most of the physico-chemical parameters were also significantly different with respect to the altitude ranges and rivers. Clear intra

  3. Decibel attenuation of pulsed electromagnetic field (PEMF) in blood and cortical bone determined experimentally and from the theory of ohmic losses.

    Science.gov (United States)

    Zborowski, Maciej; Kligman, Boris; Midura, Ronald J; Wolfman, Alan; Patterson, Thomas E; Ibiwoye, Michael; Grabiner, Mark

    2006-06-01

    We studied the PEMF power attenuation in tissues representative of clinical applications (blood and cortical bone) to determine the amount of power available for PEMF purported biological effects. The experimental system consisted of a pair of nearly circular, parallel and coaxial coils separated by a distance of one coil diameter. The power attenuation was measured using a small search coil connected to a digital oscilloscope. The coils were powered by a voltage switch operating at two different frequencies (3.8 and 63 kHz) producing bursts of pulses (numbering 21 and 1619) and triggered at two different frequencies (1.5 and 15 Hz, respectively). The tissue samples were placed inside the coils so as to expose them to either transverse electric field (at the center of coils) or the transverse magnetic field (at the coil wire). The cylindrical coil geometry yielded closed-form expressions for power attenuation based on magnetic diffusion equation and ohmic losses due to bulk tissue magnetic permeability and electrical conductivity. The measured power attenuation at these PEMF frequencies of not more than one decibel (1 dB) was well explained by the theory for the 3.8 kHz but less so for the 63 kHz frequency PEMF. The results provide important insights regarding physical mechanism of weak PEMF power dissipation in tissues.

  4. 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

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

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    Carmen Dragomir

    2012-05-01

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

  6. Distribution of millipedes along an altitudinal gradient in the south of Lake Teletskoye, Altai Mts, Russia (Diplopoda

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    Julia S. Nefedieva

    2015-06-01

    Full Text Available The distribution of millipedes along an altitudinal gradient in the south of Lake Teletskoye, Altai, Russia based on new samples from the Kyga Profile sites, as well as on partly published and freshly revised material (Mikhaljova et al. 2007, 2008, 2014, Nefedieva and Nefediev 2008, Nefediev and Nefedieva 2013, Nefedieva et al. 2014, is established. The millipede diversity is estimated to be at least 15 species and subspecies from 10 genera, 6 families and three orders. The bulk of species diversity is confined both to low- and mid-mountain chern taiga forests and high-mountain shrub tundras, whereas the highest numbers, reaching up to 130 ind./m², is shown in subalpine Pinus sibirica sparse growths. Based on clustering studied localities on species diversity similarity two groups of sites are defined: low-mountain sites and subalpine sparse growths of P. sibirica ones.

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

    Science.gov (United States)

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

    2016-04-01

    Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change. © 2016 John Wiley & Sons Ltd.

  8. DIVERSIDAD Y DISTRIBUCIÓN DE LA FAUNA QUIROPTERA EN UN TRANSECTO ALTITUDINAL EN EL DEPARTAMENTO DEL TOLIMA,COLOMBIA

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    BEJARANO-BONILLA DAVID ALFONSO

    2007-12-01

    Full Text Available Se estudió la diversidad y la distribución de la quiroterofauna registrada sobreun sector de la vertiente Oriental de la cordillera Central en el departamento delTolima, en un transecto altitudinal dividido en cuatro zonas de muestreo (I: 350-1000; II: 1000-2000; III: 2000-3000 y IV: 3000-4000. Se encontraron 42 especiescorrespondientes a 21 géneros y cuatro familias. La familia Phyllostomidae fuelas más diversa y abundante, con 34 especies y 92.5% del número de individuoscolectados. Por su parte, entre las zonas estudiadas la que presentó la mayordiversidad y abundancia fue la zona II, que correspondió a elevaciones intermedias.El género Sturnira presentó el rango más amplio de distribución, mientras el númerode especies del género Artibeus descendió a medida que se incrementó la altitud.Las especies Sturnira lilium, Sturnira luisi, Sturnira erythromos, Sturnira ludovici,Carollia perspicillata, Myotis keaysi, Artibeus cf. phaeotis y Desmodus rotundus,tuvieron los rangos de distribución altitudinal más amplios. La única especieregistrada en nuestros muestreos sobre los 3000 m fue Histiotus montanus. Oncenuevos reportes de especies de murciélagos son adicionados para el departamentodel Tolima: Chiroderma salvini, Lonchophylla mordax, Molossops planirostris,Myotis keaysi, Promops centralis, Pteronotus parnellii, Sturnira aratathomasi, S.bogotensis, S. luisi, S. tildae, Vampyrops aurarius y cinco para la zona andina delpaís: Ch. salvini, M. planirostris, S. luisi, S. tildae y V. aurarius. Esta investigaciónevidencia la necesidad de estudiar sistemáticamente regiones que aportan datosimportantes sobre la comunidad de murciélagos de Colombia.

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

    Science.gov (United States)

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

    2016-01-01

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

  10. Ampliación del rango altitudinal de Marmosa lepida (Thomas, 1888 (Didelphimorphia: Didelphidae en el sureste de Ecuador

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    Brito, Jorge

    2015-12-01

    Full Text Available The Rufous mouse opossum Marmosa lepida is the smallest in the genus Marmosa and one of the least understood and studied. An expedition to the mountains of Kutukú, in southeastern Ecuador, revealed an adult male specimen which was collected while descending from a tree. The information presented here extends the altitudinal range to 1581 meters above sea level at the crest of a ridge in the Kutukú range, and represents the sixth documented locality in Ecuador. The difficulty of trapping and registering some small mammals with conventional methods hinders knowledge of the distribution of many poorly known species and consequently the application of measures for conservation action.La raposa chica radiante Marmosa lepida es el marsupial más pequeño dentro del género y uno de los menos conocidos y estudiados a nivel de historia natural. En una expedición desarrollada a la cordillera de Kutukú al suroriente de Ecuador, se colectó un ejemplar macho adulto mientras descendía de un árbol. La información aquí presentada amplía el rango altitudinal a 1581 msnm en la cresta de la cordillera de Kutukú, y representa la sexta localidad documentada para Ecuador. La dificultad de registro de varios pequeños mamíferos con métodos convencionales dificulta el conocimiento de la distribución de numerosas especies poco conocidas y por ende la aplicación de medidas de acción para la conservación.

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

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    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.

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

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    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. 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

  14. 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.

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

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    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

  16. Driving with Central Visual Field Loss II: How Scotomas above or below the Preferred Retinal Locus (PRL Affect Hazard Detection in a Driving Simulator.

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    P Matthew Bronstad

    Full Text Available We determined whether binocular central scotomas above or below the preferred retinal locus affect detection of hazards (pedestrians approaching from the side. Seven participants with central field loss (CFL, and seven age-and sex-matched controls with normal vision (NV, each completed two sessions of 5 test drives (each approximately 10 minutes long in a driving simulator. Participants pressed the horn when detecting pedestrians that appeared at one of four eccentricities (-14°, -4°, left, 4°, or 14°, right, relative to car heading. Pedestrians walked or ran towards the travel lane on a collision course with the participant's vehicle, thus remaining in the same area of the visual field, assuming participant's steady forward gaze down the travel lane. Detection rates were nearly 100% for all participants. CFL participant reaction times were longer (median 2.27s, 95% CI 2.13 to 2.47 than NVs (median 1.17s, 95%CI 1.10 to 2.13; difference p<0.01, and CFL participants would have been unable to stop for 21% of pedestrians, compared with 3% for NV, p<0.001. Although the scotomas were not expected to obscure pedestrian hazards, gaze tracking revealed that scotomas did sometimes interfere with detection; late reactions usually occurred when pedestrians were entirely or partially obscured by the scotoma (time obscured correlated with reaction times, r = 0.57, p<0.001. We previously showed that scotomas lateral to the preferred retinal locus delay reaction times to a greater extent; however, taken together, the results of our studies suggest that any binocular CFL might negatively impact timely hazard detection while driving and should be a consideration when evaluating vision for driving.

  17. Modelling the risk of visual field loss arising from long-term exposure to the antiepileptic drug vigabatrin: a cross-sectional approach.

    Science.gov (United States)

    Wild, John M; Fone, David L; Aljarudi, Saleh; Lawthom, Charlotte; Smith, Philip E M; Newcombe, Robert G; Lewis, Gareth D

    2013-10-01

    The antiepileptic drug vigabatrin has been used widely since 1989, but has only been approved for use in the US since 2009. The risk:benefit of vigabatrin is generally predicated upon an assumed frequency of associated visual field loss (VAVFL) of approximately 31 %. This estimate is based upon relatively short-term usage (up to 4-5 years) and it is essential to determine whether the frequency of VAVFL increases with longer-term usage. The aim of this study was to model, from cross-sectional evidence, over greater ranges of treatment duration and cumulative dose than previously evaluated, the risk (frequency) of VAVFL with increasing exposure to vigabatrin. This was a retrospective cohort study undertaken in a regional hospital epilepsy clinic. The cohort comprised 147 consecutive patients treated with vigabatrin for refractory complex partial (focal) seizures, who had all undergone ophthalmological examination and who had undertaken perimetry, reliably, according to a standard and robust protocol. The visual field plots were evaluated masked to treatment duration and dose. The risk (frequency) of VAVFL with increasing exposure to vigabatrin was modelled, from the cross-sectional evidence, by standard and plateau logistic regression. The cohort comprised 80 females and 67 males (mean age 40.3 years, standard deviation 13.7). The median duration of vigabatrin exposure was 7.9 years (interquartile range 3.6-11.0, range 0.2-16.1 years); 46 patients (31 %) had received vigabatrin for over 10 years. Eighty-seven patients (59 %) exhibited VAVFL; the proportion with VAVFL was higher in males (66 %) than females (54 %). The plateau model for duration and for cumulative dose exhibited a better fit than the standard model (both p risk:benefit for VAVFL with increasing long-term exposure to vigabatrin and the ensuing increased cost:benefit resulting from the necessary additional visual assessments.

  18. 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?

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    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

  19. Synergistic role of hydroxyapatite nanoparticles and pulsed electromagnetic field therapy to prevent bone loss in rats following exposure to simulated microgravity

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    D Prakash

    2009-07-01

    Full Text Available D Prakash, J BehariSchool of Environmental Sciences, Jawaharlal Nehru University, New Delhi, IndiaAbstract: The purpose of the present study was to use capacitive coupling of pulsed electromagnetic field (CC-PEMF and hydroxyapatite nanoparticles (HAp as a countermeasure to prevent osteoporosis induced by simulated microgravity. We used the hind-limb suspension (HLS rat model to simulate microgravity-induced bone losses for 45 days. In order to compare the resulting changes, mineralogical (bone mineral density [BMD], calcium [Ca], and phosphorus [P], biochemical (osteocalcin, alkaline phosphatase [ALP], and type I collagen, and histological (scanning electron microscopy parameters were adopted. As a countermeasure to the above, the effect of PEMF and HAp application were examined. Three-month-old female Wistar rats were randomly divided into control (n = 8, HLS (n = 8, HLS with PEMF (n = 8, HLS with HAp nanoparticles (n = 8, and HLS with HAp and PEMF (n = 8. We observed: 1 significant decrease (p < 0.01 in BMD, Ca, P, type I collagen, and ALP activity in femur and tibia in hind-limb bone and serum osteocalcin in HLS rats as compared with the ground control. 2 Nonsignificant increase in BMD (p < 0.1, Ca (p < 0.1, P (p < 0.5, type I collagen (p < 0.1, and ALP activity (p < 0.5 in femur and tibia in hind-limb bone and serum osteocalcin (p < 0.5 in HLS + PEMF rats compared with HLS rats. 3 Significant increase in BMD (p < 0.02, Ca (p < 0.05, P (p < 0.05, type I collagen (p < 0.02, and ALP activity (p > 0.02 in femur and tibia in hind-limb bone with a nonsignificant increase in serum osteocalcin (p > 0.1 in HLS + HAp rats compared to HLS rats. 4 Significant increase in BMD (p > 0.01. Ca (p > 0.01. P (p > 0.01. type I collagen (p > 0.01. and ALP activity (p > 0.01 in femur and tibia in hind-limb bone and serum osteocalcin (p > 0.02 were also observed. Results suggest that a combination of low level PEMF and Hap nanoparticles has potential to control

  20. 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.

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

    Science.gov (United States)

    Siles, José A; Margesin, Rosa

    2016-07-01

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

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

    Science.gov (United States)

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

    2014-05-01

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

  3. Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia.

    Science.gov (United States)

    Yared, Solomon; Gebresilassie, Araya; Akililu, Essayas; Deribe, Kebede; Balkew, Meshesha; Warburg, Alon; Hailu, Asrat; Gebre-Michael, Teshome

    2017-12-01

    The Leishmaniases are caused by the protozoan parasites of the genus Leishmania and are transmitted to humans by the bite of infected female phlebotomine sand flies. Both visceral and cutaneous leishmaniases are widely distributed in different parts of Ethiopia. The aim of this study was to determine the diversity and altitudinal distribution of phlebotomine sand flies from Kafta Humera to Gondar town in northwest Ethiopia. Seven localities were selected with distinct altitudinal variations between 550m above sea level (m a.s.l) and 2300m a.s.l. In each locality, sand flies were collected using standard CDC light traps and sticky traps during the active sand fly season from December 2012 to May 2013. Shannon-Weiner species diversity index and Jaccard's coefficient were used to estimate species diversity and similarity between altitudes and localities, respectively. A total of 89,044 sand flies (41,798 males and 47, 246 females) were collected from the seven localities/towns throughout the study period. Twenty-two species belonging to 11 species in the genus Phlebotomus and 11 species in the genus Sergentomyia were documented. Of these, Sergentomyia clydei (25.87%), S. schwetzi (25.21%), S. africana (24.65%), S. bedfordi (8.89%), Phlebotomus orientalis (6.43%), and S. antennata (4.8%) were the most prevalent species. The remaining 10 Phlebotomus species and six Sergentomyia were less frequent catches. In CDC light trap and sticky trap, higher species diversity and richness for both male and female sand flies was observed at low altitude ranging from 550 to 699m a.s.l in Adebay village in Kafta Humera district whereas low species richness and high evenness of both sexes were also observed in an altitude 1950-2300m a.s.l. The results revealed that the presence of leishmaniasis vectors such as P. orientalis, P. longipes, P. papatasi, and P. duboscqi in different altitudes in northwest Ethiopia. P. orientalis a vector of L. donovani, occurred between altitude 500-1100m

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

    Science.gov (United States)

    González, Camila; Paz, Andrea; Ferro, Cristina

    2014-01-01

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

  5. Hair Loss

    Science.gov (United States)

    ... conditions can cause hair loss, including: Hormonal changes. Hormonal changes and imbalances can cause temporary hair loss. This could be due to pregnancy, childbirth or the onset of menopause. Hormone levels are also affected by the thyroid ...

  6. Hair Loss

    Science.gov (United States)

    ... overall hair thinning and not bald patches. Full-body hair loss. Some conditions and medical treatments, such as ... in the loss of hair all over your body. The hair usually grows back. Patches of scaling that spread ...

  7. 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

  8. Response of pollen diversity to the climate-driven altitudinal shift of vegetation in the Colombian Andes.

    Science.gov (United States)

    Weng, Chengyu; Hooghiemstra, Henry; Duivenvoorden, Joost F

    2007-02-28

    Change in diversity of fossil pollen through time is used as a surrogate for biodiversity history. However, there have been few studies to explore the sensitivity of the measured pollen diversity to vegetation changes and the relationship between pollen diversity and plant diversity. This paper presents results of a study to assess the relationship between pollen diversity and relative abundance of pollen from different altitudinal vegetation belts (subandean forest, Andean forest, subparamo and grassparamo) in three records from the tropical Andes in Colombia. The results indicated that plant diversity in the vegetation declined with altitude and pollen diversity is positively correlated to the abundance of pollen from lower altitude vegetation belts and negatively correlated to that from the grassparamo. These results, therefore, suggest that pollen diversity coarsely reflects the diversity of the surrounding vegetation. Using this interpretation, we were able to predict changes in plant diversity over the past 430000 years in the Colombian Andes. Results indicated that under warmer climatic conditions, more species-diverse vegetation of low elevation moved upslope to contribute more pollen diversity to the study sites, and under colder conditions, species-poor grassparamo moved downslope and observed pollen diversity was lower. This study concludes that fossil pollen diversity may provide an important proxy to reconstruct the temporal changes in plant diversity.

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

    DEFF Research Database (Denmark)

    Gudbergsen, H; Boesen, M; Lohmander, L S

    2012-01-01

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

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

    Science.gov (United States)

    Illig, Jens; Norton, Roy A.; Scheu, Stefan

    2010-01-01

    Microarthropod communities in the soil and on the bark of trees were investigated along an elevation gradient (1,850, 2,000, 2,150, 2,300 m) in a tropical montane rain forest in southern Ecuador. We hypothesised that the density of microarthropods declines with depth in soil and increases with increasing altitude mainly due to the availability of resources, i.e. organic matter. In addition, we expected bark and soil communities to differ strongly, since the bark of trees is more exposed to harsher factors. In contrast to our hypothesis, the density of major microarthropod groups (Collembola, Oribatida, Gamasina, Uropodina) was generally low and decreased with altitude. However, as we predicted the density of each of the groups decreased with soil depth. Density of microarthropods on tree bark was lower than in soil. Overall, 43 species of oribatid mites were found, with the most abundant higher taxa being Poronota, pycnonotic Apheredermata, Mixonomata and Eupheredermata. The oribatid mite community on bark did not differ significantly from that in soil. The number of oribatid mite species declined with altitude (24, 23, 17 and 13 species at 1,850, 2,000, 2,150 and 2,300 m, respectively). Rarefaction curves indicate that overall about 50 oribatid mite species are to be expected along the studied altitudinal gradient. Results of this study indicate (1) that microarthropods may be limited by the quality of resources at high altitudes and by the amount of resources at deeper soil layers, and (2) that the bark of trees and the soil are habitats of similar quality for oribatid mites. Electronic supplementary material The online version of this article (doi:10.1007/s10493-010-9348-x) contains supplementary material, which is available to authorized users. PMID:20229099

  11. Towards monitoring biodiversity in Amazonian forests: how regular samples capture meso-scale altitudinal variation in 25 km2 plots.

    Science.gov (United States)

    Norris, Darren; Fortin, Marie-Josée; Magnusson, William E

    2014-01-01

    Ecological monitoring and sampling optima are context and location specific. Novel applications (e.g. biodiversity monitoring for environmental service payments) call for renewed efforts to establish reliable and robust monitoring in biodiversity rich areas. As there is little information on the distribution of biodiversity across the Amazon basin, we used altitude as a proxy for biological variables to test whether meso-scale variation can be adequately represented by different sample sizes in a standardized, regular-coverage sampling arrangement. We used Shuttle-Radar-Topography-Mission digital elevation values to evaluate if the regular sampling arrangement in standard RAPELD (rapid assessments ("RAP") over the long-term (LTER ["PELD" in Portuguese])) grids captured patters in meso-scale spatial variation. The adequacy of different sample sizes (n = 4 to 120) were examined within 32,325 km2/3,232,500 ha (1293×25 km2 sample areas) distributed across the legal Brazilian Amazon. Kolmogorov-Smirnov-tests, correlation and root-mean-square-error were used to measure sample representativeness, similarity and accuracy respectively. Trends and thresholds of these responses in relation to sample size and standard-deviation were modeled using Generalized-Additive-Models and conditional-inference-trees respectively. We found that a regular arrangement of 30 samples captured the distribution of altitude values within these areas. Sample size was more important than sample standard deviation for representativeness and similarity. In contrast, accuracy was more strongly influenced by sample standard deviation. Additionally, analysis of spatially interpolated data showed that spatial patterns in altitude were also recovered within areas using a regular arrangement of 30 samples. Our findings show that the logistically feasible sample used in the RAPELD system successfully recovers meso-scale altitudinal patterns. This suggests that the sample size and regular arrangement

  12. 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)

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

    Directory of Open Access Journals (Sweden)

    Carlos Lara-Romero

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

  14. 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

  15. 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

  16. Loss of chance: what loss?

    Science.gov (United States)

    Bird, Sara

    2006-05-01

    A recent New South Wales judgment, Rufo v Hosking, explored the concept of 'loss of a chance' in medical negligence claims. 'Loss of a chance' claims involve an allegation that the patient lost the chance of a better outcome as a result of the negligence of the medical practitioner. This article outlines the case and discusses the implications of the judgment for medical practitioners.

  17. Hair Loss

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    ... and Nutrition Healthy Food Choices Weight Loss and Diet Plans Nutrients and Nutritional Info Sugar and Sugar Substitutes Exercise and Fitness Exercise Basics Sports Safety Injury Rehabilitation Emotional Well-Being Mental Health ...

  18. Memory loss

    Science.gov (United States)

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

  19. Hair Loss

    Science.gov (United States)

    ... hair bulb. This is where the hair's color pigment, or melanin, is produced. Most people lose about ... diabetes or thyroid disease , can interfere with hair production and cause hair loss. People with lupus can ...

  20. Hidden loss

    DEFF Research Database (Denmark)

    Kieffer-Kristensen, Rikke; Johansen, Karen Lise Gaardsvig

    2013-01-01

    finding indicates that the children experienced numerous losses, many of which were often suppressed or neglected by the children to protect the ill parents. CONCLUSIONS: The findings indicated that the children seemed to make a special effort to hide their feelings of loss and grief in order to protect...... the ill parent. These findings contribute to a deeper understanding of the traumatic process of parental ABI that some children experience and emphasize the importance of family-centred interventions that include the children....

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

    Science.gov (United States)

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

    2016-04-01

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

  2. Upward Altitudinal Shifts in Habitat Suitability of Mountain Vipers since the Last Glacial Maximum.

    Science.gov (United States)

    Yousefi, Masoud; Ahmadi, Mohsen; Nourani, Elham; Behrooz, Roozbeh; Rajabizadeh, Mehdi; Geniez, Philippe; Kaboli, Mohammad

    2015-01-01

    We determined the effects of past and future climate changes on the distribution of the Montivipera raddei species complex (MRC) that contains rare and endangered viper species limited to Iran, Turkey and Armenia. We also investigated the current distribution of MRC to locate unidentified isolated populations as well as to evaluate the effectiveness of the current network of protected areas for their conservation. Present distribution of MRC was modeled based on ecological variables and model performance was evaluated by field visits. Some individuals at the newly identified populations showed uncommon morphological characteristics. The distribution map of MRC derived through modeling was then compared with the distribution of protected areas in the region. We estimated the effectiveness of the current protected area network to be 10%, which would be sufficient for conserving this group of species, provided adequate management policies and practices are employed. We further modeled the distribution of MRC in the past (21,000 years ago) and under two scenarios in the future (to 2070). These models indicated that climatic changes probably have been responsible for an upward shift in suitable habitats of MRC since the Last Glacial Maximum, leading to isolation of allopatric populations. Distribution will probably become much more restricted in the future as a result of the current rate of global warming. We conclude that climate change most likely played a major role in determining the distribution pattern of MRC, restricting allopatric populations to mountaintops due to habitat alterations. This long-term isolation has facilitated unique local adaptations among MRC populations, which requires further investigation. The suitable habitat patches identified through modeling constitute optimized solutions for inclusion in the network of protected areas in the region.

  3. Upward Altitudinal Shifts in Habitat Suitability of Mountain Vipers since the Last Glacial Maximum.

    Directory of Open Access Journals (Sweden)

    Masoud Yousefi

    Full Text Available We determined the effects of past and future climate changes on the distribution of the Montivipera raddei species complex (MRC that contains rare and endangered viper species limited to Iran, Turkey and Armenia. We also investigated the current distribution of MRC to locate unidentified isolated populations as well as to evaluate the effectiveness of the current network of protected areas for their conservation. Present distribution of MRC was modeled based on ecological variables and model performance was evaluated by field visits. Some individuals at the newly identified populations showed uncommon morphological characteristics. The distribution map of MRC derived through modeling was then compared with the distribution of protected areas in the region. We estimated the effectiveness of the current protected area network to be 10%, which would be sufficient for conserving this group of species, provided adequate management policies and practices are employed. We further modeled the distribution of MRC in the past (21,000 years ago and under two scenarios in the future (to 2070. These models indicated that climatic changes probably have been responsible for an upward shift in suitable habitats of MRC since the Last Glacial Maximum, leading to isolation of allopatric populations. Distribution will probably become much more restricted in the future as a result of the current rate of global warming. We conclude that climate change most likely played a major role in determining the distribution pattern of MRC, restricting allopatric populations to mountaintops due to habitat alterations. This long-term isolation has facilitated unique local adaptations among MRC populations, which requires further investigation. The suitable habitat patches identified through modeling constitute optimized solutions for inclusion in the network of protected areas in the region.

  4. 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.

  5. 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.

  6. Altitudinal migration and the future of an iconic Hawaiian honeycreeper in response to climate change and management

    Science.gov (United States)

    Guillaumet, Alban; Kuntz, Wendy A.; Samuel, Michael D.; Paxton, Eben H.

    2017-01-01

    Altitudinal movement by tropical birds to track seasonally variable resources can move them from protected areas to areas of increased vulnerability. In Hawaiʻi, historical reports suggest that many Hawaiian honeycreepers such as the ‘I‘iwi (Drepanis coccinea) once undertook seasonal migrations, but the existence of such movements today is unclear. Because Hawaiian honeycreepers are highly susceptible to avian malaria, currently minimal in high-elevation forests, understanding the degree to which honeycreepers visit lower elevation forests may be critical to predict the current impact of malaria on population dynamics and how susceptible bird populations may respond to climate change and mitigation scenarios. Using radio telemetry data, we demonstrate for the first time that a large fraction of breeding adult and juvenile ‘I‘iwi originating from an upper-elevation (1,920 m) population at Hakalau Forest National Wildlife Refuge exhibit post-breeding movements well below the upper elevational limit for mosquitoes. Bloom data suggest seasonal variation in floral resources is the primary driver of seasonal movement for ‘I‘iwi. To understand the demographic implications of such movement, we developed a spatial individual-based model calibrated using previously published and original data. ʻI‘iwi dynamics were simulated backward in time, to estimate population levels in the absence of avian malaria, and forward in time, to assess the impact of climate warming as well as two potential mitigation actions. Even in disease-free ‘refuge’ populations, we found that breeding densities failed to reach the estimated carrying capacity, suggesting the existence of a seasonal “migration load” as a result of travel to disease-prevalent areas. We predict that ‘I‘iwi may be on the verge of extinction in 2100, with the total number of pairs reaching only ~ 0.2–12.3% of the estimated pre-malaria density, based on an optimistic climate change scenario. The

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

    Directory of Open Access Journals (Sweden)

    Sabuj Bhattacharyya

    2010-06-01

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

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

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2018-04-01

    Full Text Available 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

  9. Hearing Loss

    Science.gov (United States)

    ... law Sound level, decibels Duration, daily BASED ON OCCUPATIONAL SAFETY & HEALTH ADMINISTRATION, 2008 90 8 hours 92 6 hours 95 4 hours 97 3 hours 100 2 hours 102 1.5 hours 105 1 hour 110 30 minutes 115 15 minutes or less Complications Hearing loss can have a significant effect on your quality ...

  10. Experiencing Loss

    DEFF Research Database (Denmark)

    Kristiansen, Maria; Younis, Tarek; Hassani, Amani

    2015-01-01

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

  11. Review of field and monitoring studies investigating the role of nitro-substituted neonicotinoid insecticides in the reported losses of honey bee colonies (Apis mellifera).

    Science.gov (United States)

    Schmuck, Richard; Lewis, Gavin

    2016-11-01

    The nitro-substituted neonicotinoid insecticides, which include imidacloprid, thiamethoxam and clothianidin, are widely used to control a range of important agricultural pests both by foliar applications and also as seed dressings and by soil application. Since they exhibit systemic properties, exposure of bees may occur as a result of residues present in the nectar and/or pollen of seed- or soil-treated crop plants and so they have been the subject of much debate about whether they cause adverse effects in pollinating insects under field conditions. Due to these perceived concerns, the use of the three neonicotinoids imidacloprid, clothianidin and thiamethoxam has been temporarily suspended in the European Union for seed treatment, soil application and foliar treatment in crops attractive to bees. Monitoring data from a number of countries are available to assess the presence of neonicotinoid residues in honey bee samples and possible impacts at the colony level and these are reviewed here together with a number of field studies which have looked at the impact of clothiandin on honey bees in relation to specific crop use and in particular with oilseed rape. Currently there is considerable uncertainty with regards to the regulatory testing requirements for field studies. Accordingly, a testing protocol was developed to address any acute and chronic risks from oilseed rape seeds containing a coating with 10 g clothianidin and 2 g beta-cyfluthrin per kg seeds (Elado ® ) for managed honey bee (Apis mellifera) colonies, commercially bred bumble bee (Bombus terrestris) colonies and red mason bees (Osmia bicornis) as a representative solitary bee species. This is described here together with a summary of the results obtained as an introduction to the study details given in the following papers in this issue.

  12. Significant correlations between optic nerve head microcirculation and visual field defects and nerve fiber layer loss in glaucoma patients with myopic glaucomatous disk

    Directory of Open Access Journals (Sweden)

    Yokoyama Y

    2011-12-01

    Full Text Available Yu Yokoyama, Naoko Aizawa, Naoki Chiba, Kazuko Omodaka, Masahiko Nakamura, Takaaki Otomo, Shunji Yokokura, Nobuo Fuse, Toru NakazawaDepartment of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, JapanBackground: Eyes with glaucoma are characterized by optic neuropathy with visual field defects in the areas corresponding to the optic disk damage. The exact cause for the glaucomatous optic neuropathy has not been determined. Myopia has been shown to be a risk factor for glaucoma. The purpose of this study was to determine whether a significant correlation existed between the microcirculation of the optic disk and the visual field defects and the retinal nerve fiber layer thickness (RNFLT in glaucoma patients with myopic optic disks.Methods: Sixty eyes of 60 patients with myopic disks were studied; 36 eyes with glaucoma (men:women = 19:17 and 24 eyes with no ocular diseases (men:women = 14:10. The mean deviation (MD determined by the Humphrey field analyzer, and the peripapillary RNFLT determined by the Stratus-OCT were compared between the two groups. The ocular circulation was determined by laser speckle flowgraphy (LSFG, and the mean blur rate (MBR was compared between the two groups. The correlations between the RNFLT and MBR of the corresponding areas of the optic disk and between MD and MBR of the optic disk in the glaucoma group were determined by simple regression analyses.Results: The average MBR for the entire optic disk was significantly lower in the glaucoma group than that in the control group. The differences of the MBR for the tissue in the superior, inferior, and temporal quadrants of the optic disk between the two groups were significant. The MBR for the entire optic disk was significantly correlated with the MD (r = 0.58, P = 0.0002 and the average RNFLT (r = 0.53, P = 0.0008. The tissue MBR of the optic disk was significantly correlated with the RNFLT in the superior, inferior, and temporal quadrants

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

    Directory of Open Access Journals (Sweden)

    Mai A Elobeid

    2009-08-01

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

  14. 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

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

    OpenAIRE

    Jorge Sarmiento Téllez; Julio César Betancur

    2006-01-01

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

  16. Optimation Pressure Loss to Oil Production System with Electrical Submersible Pump (ESP) at the Well A SW Field Bojonegoro, East Java

    Science.gov (United States)

    Ilmah, A. M.; Hendrajaya, L.

    2017-07-01

    Study about oil and gas well A and SW fields have been conducted in Bojonegoro area, East Java Province. From the research, it is known that one of the constrain in oil and gas production process is a pressure drop, so that is necessary to set Electrical Submersible Pump (ESP) as an artificial lift pump at low pressure wells. It is needed to analyze the production well pressure as an effort to optimize the fluid production. It is in describe to relations between IPR (Inflow Performance Relationship ) curve with TPR (Tubing Performance Relationship), are getting down point cut TPR curve with IPR curve, fluid rate its optimal, so need tubing’s diameter variation and the number of stage pump ESP variation to can the most optimal fluid rate. Produced that to tubing variation are 2,441 ID is 876,729 bpd, 2,991 is 961,197 bpd, 3,476 id is 996, 26 Bpd, while on the number of stage pump esp variation The most high is stage 400 with fluid rate 961,197 by comparison stage 338 it has value fluid rate 921,165 bpd, stage 200 it has fluid rate 827,889 bpd, and stage 169 has fluid rate 774,646 bpd. Of some variation tubing and stage pumps that has the most influence to fluid rate optimalize is the change number of stage pump.

  17. 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

  18. Field analysis

    Directory of Open Access Journals (Sweden)

    Waindok Andrzej

    2017-12-01

    Full Text Available Field analysis including eddy currents in the magnetic core of five-phase permanent magnet tubular linear actuator (TLA has been carried out. The eddy currents induced in the magnetic core cause the losses which have been calculated. The results from 2D finite element (FE analysis have been compared with those from 3D calculations. The losses in the mover of the five-phase actuator are much lower than the losses in its stator. That is why the former ones can be neglected in the computer aided designing. The calculation results have been verified experimentally

  19. [A field study of tundra plant litter decomposition rate via mass loss and carbon dioxide emission: the role of biotic and abiotic controls, biotope, season of year, and spatial-temporal scale].

    Science.gov (United States)

    Pochikalov, A V; Karelin, D V

    2014-01-01

    Although many recently published original papers and reviews deal with plant matter decomposition rates and their controls, we are still very short in understanding of these processes in boreal and high latiude plant communities, especially in permafrost areas of our planet. First and foremost, this is holds true for winter period. Here, we present the results of 2-year field observations in south taiga and south shrub tundra ecosystems in European Russia. We pioneered in simultaneous application of two independent methods: classic mass loss estimation by litter-bag technique, and direct measurement of CO2 emission (respiration) of the same litter bags with different types of dead plant matter. Such an approach let us to reconstruct intra-seasonal dynamics of decomposition rates of the main tundra litter fractions with high temporal resolution, to estimate the partial role of different seasons and defragmentation in the process of plant matter decomposition, and to determine its factors under different temporal scale.

  20. The impact of mild, moderate, and severe visual field loss in glaucoma on patients' quality of life measured via the Glaucoma Quality of Life-15 Questionnaire: A meta-analysis.

    Science.gov (United States)

    Wang, Yue; Alnwisi, Sameh; Ke, Min

    2017-12-01

    We performed a meta-analysis to determine the impact of mild, moderate, and severe visual field loss on quality of life (QoL) in patients with glaucoma. A comprehensive literature search was performed using the PubMed, Excerpta Medica dateBASE and China National Knowledge Infrastructure databases to identify relevant articles published before June 30, 2016. Patients' QoL was measured using the Glaucoma Quality of Life-15 Questionnaire (GQL-15). In total, 401 patients with glaucoma and 205 patients without glaucoma participated in 4 experiments. The GQL-15 summary scores are statistically different between patients with and without glaucoma (standard mean difference [SMD] = 0.94, 95% confidence interval [CI]: 0.73-1.16, P glaucoma; the SMDs for their summary scores were as follows: mild: 1.24, 95% CI: 0.26 to 2.22, P = .01; moderate: 2.05, 95% CI: 0.91 to 3.19, P glaucoma. In addition, summary scores and all 4 factor scores differed significantly between patients with mild and severe glaucoma. Moreover, summary scores and 3 factor scores (peripheral vision, glare and dark adaptation, and outdoor mobility) differed significantly between patients with moderate and severe glaucoma. However, scores for 1 factor (central and near vision) did not differ significantly between any of the patient groups (SDM = -0.53, 95% CI = -1.33 to 0.27, P = .19). Glaucoma patients with visual field loss showed significantly poorer QoL relative to that of patients without glaucoma. Patients' QoL decreased as their glaucoma severity increased.

  1. Weight-loss medicines

    Science.gov (United States)

    Prescription weight loss drugs; Diabetes - weight loss drugs; Obesity - weight loss drugs; Overweight - weight loss drugs ... Several weight-loss medicines are available. About 5 to 10 pounds (2 to 4.5 kilograms) can be lost by ...

  2. Magnetization loss of nanocrystalline soft magnets

    International Nuclear Information System (INIS)

    Flohrer, Sybille; Herzer, Giselher

    2009-01-01

    FeCuNbSiB-ribbons with optimized nanocrystalline microstructure possess a unique combination of near-zero magnetostriction, high saturation induction and low magnetization losses. Due to the absence of distinct intrinsic anisotropies, the magnetization curve can be adjusted by field-annealing to square or flat shape. It is well known that excess losses are an important loss component of soft magnets with square hysteresis loop. Yet, even cores of flat type loop can show significant excess losses. The paper reviews the loss mechanisms for excess losses in nanocrystalline soft magnets on the basis of Kerr-microscopy observation and loss theory and compares it to amorphous materials.

  3. Résorption foliaire chez Quercus petraea subsp. iberica et Arbutus andrachne le long d'un gradient altitudinal

    OpenAIRE

    Kilic, Duygu; Kutbay, Hamdi Güray; Ozbucak, Tuğba; Huseyinova, Rena

    2010-01-01

    International audience; The resorption of nutrients (mainly N and P) from senescing leaves may be a key component of adaptive mechanisms that conserve scarce nutrients. Resorption may be expressed in two ways as resorption efficiency (RE) which is the ratio of the resorbed amounts of nutrient losses during leaf senescence in relation to its prior amount deposited in leaves and resorption proficiency (RP) is the level to which nutrient concentration per unit leaf mass is reduced in senescent l...

  4. 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.

  5. 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

  6. Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three international references (IOTF, CDC and WHO).

    Science.gov (United States)

    Meyer, Elena; Carrillo, Rafael; Román, Estela María; Bejarano, Ignacio Felipe; Dipierri, José Edgardo

    2013-12-01

    INTRODUCTION. Prevalences of overweight and obesity in students from different altitudinal zones of Jujuy are compared using the International Obesity Task Force (IOTF), the Centers for Disease Control (CDC) and the World Health Organization (WHO) references, and the agreement among them. MATERIAL AND METHODS. Weight and height data from 15 541 students were grouped in highlands (HL) (≥2500 MASL) and lowlands (LL) (references. The differences in outcome measures and prevalences were established using the ?2 test and the t test, and agreement among the criteria was calculated using the kappa index. RESULTS. Students from the HL had lower weight, height and body mass index (BMI) values (preference were higher, except for overweight in students of both sexes, from 11 to 12.99 years old, from the HL and the LL. Regardless of the references, gender and age, overweight and obesity prevalences were generally higher in the LL. Agreement between the IOTF and the CDC was good-very good, and agreement among them and the WHO was fair-moderate. CONCLUSIONS. Students from the HL had a lower overweight and obesity prevalence. The greatest agreement was observed between the IOTF and the CDC references.

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

    Science.gov (United States)

    Chen, Zixun; Wang, Guoan; Jia, Yufu

    2017-01-01

    Previous studies have suggested foliar δ 13 C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ 13 C. We noted that all the studies in which δ 13 C increased with elevation were conducted in the human regions, whereas those investigations in which δ 13 C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ 13 C with elevation is not a general one, and that δ 13 C 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 δ 13 C 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 δ 13 C by accounting for the effects of temperature and precipitation on δ 13 C. This study found that the residual foliar δ 13 C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ 13 C.

  8. 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.

  9. Niche partitioning among two Ceratitis rosa morphotypes and other Ceratitis pest species (Diptera, Tephritidae) along an altitudinal transect in Central Tanzania.

    Science.gov (United States)

    Mwatawala, Maulid; Virgilio, Massimiliano; Joseph, Jane; De Meyer, Marc

    2015-01-01

    Two standard parapheromones, trimedlure (routinely used for monitoring Ceratitis rosa and Ceratitis capitata) and terpinyl acetate (routinely used for monitoring Ceratitis cosyra) were compared with enriched ginger root oil (EGO) lure for detecting and monitoring the presence and relative population abundance of these particular pest species. Standard yellow fruit fly traps were used for the comparison, which was conducted at 10 sites along an altitudinal transect ranging from 540 to 1650 masl on the Uluguru mountains, in Morogoro Region (Central Tanzania). A gradual change of relative occurrence of the two Ceratitis rosa morphotypes was clear from the EGO lure trapping. The morphotype R1 was predominant at lower altitudes while morphotype R2 was predominant at higher altitudes. Further experiments are needed to confirm the consistency of the observed pattern across regions, seasons and years as well as possible differences in the developmental physiology of both morphotypes. The mango fruit fly, Ceratitis cosyra, showed a distinct predominance at altitudes below 800 masl as shown in both the EGO lure and the terpinyl acetate trapping. The catches of all three target species were higher in traps with the EGO lure compared to the conventional lures trimedlure and terpinyl acetate. It is argued that for these species EGO lure can act as a suitable and more effective alternative for trimedlure and terpinyl acetate parapheromones. In addition, EGO lure has the added advantage that it combines the taxon spectrum for the two latter substances, thus requiring the use of only a single attractant.

  10. 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.

  11. 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.

  12. Living with vision loss

    Science.gov (United States)

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

  13. What's Hearing Loss?

    Science.gov (United States)

    ... Loss There are a few different types of hearing loss: conductive , sensorineural , mixed (conductive and sensory combined), neural , and central . Conductive (say: kun- duk -tiv) hearing loss. This happens when there is a problem with ...

  14. OI Issues: Hearing Loss

    Science.gov (United States)

    ... loss can occur at any age, including childhood. Conductive Hearing Loss : Usually results from a physical problem in the ... This type of test can determine if the hearing loss is conductive or sensorineural. Adults who have an identified hearing ...

  15. Diversity and distribution of Odonata (Insecta larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico

    Directory of Open Access Journals (Sweden)

    José Antonio Gómez-Anaya

    2011-12-01

    Full Text Available Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM, Michoacán, Mexico, and related it to local (site-level habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H’, Margalef’s Richness Index (R, Simpson’s Index as a dominance measure (D and Pielou’s Equitability (J were used to describe the assemblages, and Renyi’s Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76% occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi’s diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench’s curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation. Rev. Biol

  16. Diversity and distribution of Odonata (Insecta larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico

    Directory of Open Access Journals (Sweden)

    José Antonio Gómez-Anaya

    2011-12-01

    Full Text Available Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM, Michoacán, Mexico, and related it to local (site-level habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H’, Margalef’s Richness Index (R, Simpson’s Index as a dominance measure (D and Pielou’s Equitability (J were used to describe the assemblages, and Renyi’s Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76% occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi’s diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench’s curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation. Rev. Biol

  17. Diversity and distribution of Odonata (Insecta) larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico.

    Science.gov (United States)

    Gómez-Anaya, José Antonio; Novelo-Gutiérrez, Rodolfo; Campbell, William Bruce

    2011-12-01

    Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H'), Margalef's Richness Index (R), Simpson's Index as a dominance measure (D) and Pielou's Equitability (J) were used to describe the assemblages, and Renyi's Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC) was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA) was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76%) occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi's diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench's curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation.

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

    Directory of Open Access Journals (Sweden)

    Meghnath Dhimal

    2015-03-01

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

  19. Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna.

    Directory of Open Access Journals (Sweden)

    Luca Malatesta

    Full Text Available 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

  20. 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

  1. Altitudinal gradients, biogeographic history and microhabitat adaptation affect fine-scale spatial genetic structure in African and Neotropical populations of an ancient tropical tree species.

    Directory of Open Access Journals (Sweden)

    Paloma Torroba-Balmori

    Full Text Available The analysis of fine-scale spatial genetic structure (FSGS within populations can provide insights into eco-evolutionary processes. Restricted dispersal and locally occurring genetic drift are the primary causes for FSGS at equilibrium, as described in the isolation by distance (IBD model. Beyond IBD expectations, spatial, environmental or historical factors can affect FSGS. We examined FSGS in seven African and Neotropical populations of the late-successional rain forest tree Symphonia globulifera L. f. (Clusiaceae to discriminate the influence of drift-dispersal vs. landscape/ecological features and historical processes on FSGS. We used spatial principal component analysis and Bayesian clustering to assess spatial genetic heterogeneity at SSRs and examined its association with plastid DNA and habitat features. African populations (from Cameroon and São Tomé displayed a stronger FSGS than Neotropical populations at both marker types (mean Sp = 0.025 vs. Sp = 0.008 at SSRs and had a stronger spatial genetic heterogeneity. All three African populations occurred in pronounced altitudinal gradients, possibly restricting animal-mediated seed dispersal. Cyto-nuclear disequilibria in Cameroonian populations also suggested a legacy of biogeographic history to explain these genetic patterns. Conversely, Neotropical populations exhibited a weaker FSGS, which may reflect more efficient wide-ranging seed dispersal by Neotropical bats and other dispersers. The population from French Guiana displayed an association of plastid haplotypes with two morphotypes characterized by differential habitat preferences. Our results highlight the importance of the microenvironment for eco-evolutionary processes within persistent tropical tree populations.

  2. 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.

  3. 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.

  4. Mechanism and kinetics of the loss of poorly soluble drugs from liposomal carriers studied by a novel flow field-flow fractionation-based drug release-/transfer-assay.

    Science.gov (United States)

    Hinna, Askell Hvid; Hupfeld, Stefan; Kuntsche, Judith; Bauer-Brandl, Annette; Brandl, Martin

    2016-06-28

    Liposomes represent a versatile drug formulation approach e.g. for improving the water-solubility of poorly soluble drugs but also to achieve drug targeting and controlled release. For the latter applications it is essential that the drug remains associated with the liposomal carrier during transit in the vascular bed. A range of in vitro test methods has been suggested over the years for prediction of the release of drug from liposomal carriers. The majority of these fail to give a realistic prediction for poorly water-soluble drugs due to the intrinsic tendency of such compounds to remain associated with liposome bilayers even upon extensive dilution. Upon i.v. injection, in contrast, rapid drug loss often occurs due to drug transfer from the liposomal carriers to endogenous lipophilic sinks such as lipoproteins, plasma proteins or membranes of red blood cells and endothelial cells. Here we report on the application of a recently introduced in vitro predictive drug transfer assay based on incubation of the liposomal drug carrier with large multilamellar liposomes, the latter serving as a biomimetic model sink, using flow field-flow fractionation as a tool to separate the two types of liposomes. By quantifying the amount of drug remaining associated with the liposomal drug carrier as well as that transferred to the acceptor liposomes at distinct times of incubation, both the kinetics of drug transfer and release to the water phase could be established for the model drug p-THPP (5,10,15,20-tetrakis(4-hydroxyphenyl)21H,23H-porphine). p-THPP is structurally similar to temoporfin, a photosensitizer which is under clinical evaluation in a liposomal formulation. Mechanistic insights were gained by varying the donor-to-acceptor lipid mass ratio, size and lamellarity of the liposomes. Drug transfer kinetics from one liposome to another was found rate determining as compared to redistribution from the outermost to the inner concentric bilayers, such that the overall

  5. 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 d...

  6. Diversity, distribution pattern and seasonal variation in moth assemblages along altitudinal gradient in Gangotri landscape area, Western Himalaya, Uttarakhand, India

    Directory of Open Access Journals (Sweden)

    A.K. Sanyal

    2013-02-01

    Full Text Available Field survey was conducted at different altitudes and land-use areas in the two protected areas, viz., Gangotri National Park and Govind National Park of Uttarkashi District, Uttarakhand, India. A total of 475 specimens of moth representing 436 morphospecies were collected using light trap method during the survey conducted between September 2008-May 2010. Preliminary findings show a decreasing diversity with increasing altitude. Subalpine areas were least diverse and subtropical areas had the highest diversity of moths. The greatest number of specimens were collected during the summer and post-monsoon period. The lunar phase had a significant effect on catch success with new moon days resulting in the largest catches and full moon days resulting in the least number of species as well as individuals. Of the thirty two species mentioned in Appendix 1, nine species are first time record from the state Uttarakhand. Four species are new record from Western Himalaya within Indian Territory, and also first time recorded from entire Himalayan landscape. As there was no previous comprehensive study on the moth diversity of Gangotri landscape area, all the 32 species described could be regarded as new record from these two protected areas.

  7. 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

  8. 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...

  9. PREGNANCY LOSS IN MARES

    Directory of Open Access Journals (Sweden)

    Tibary A

    2015-12-01

    Full Text Available Pregnancy loss is an important aspect of equine practice due to the economic and emotional loss that it engenders. Pregnancy loss is often divided in two categories: early pregnancy loss (EPL or embryonic death (ED (first 42 days and fetal losses (after 42 days. Diagnosis of the causes of pregnancy loss is often very challenging. Many of the causes of EPL remain poorly documented but studies on embryo development and embryo-uterine interaction have been able to shed some light on predisposing factors. Fetal losses or abortions are dominated by infectious causes and particularly bacterial placentitis. Detailed reviews of pregnancy loss were recently published by the authors (Tibary et al., 2012; Tibary and Pearson, 2012; Tibary et al., 2014. The objective of this paper is to provide an overview of the epidemiology, etiology, diagnosis and prevention of pregnancy loss in the mare.

  10. Corona helps curb losses

    Energy Technology Data Exchange (ETDEWEB)

    Laasonen, M.; Lahtinen, M.; Lustre, L.

    1996-11-01

    The greatest power losses in electricity transmission arise through a phenomenon called load losses. Corona losses caused by the surface discharge of electricity also constitute a considerable cost item. IVS, the nationwide network company, is investigating corona- induced losses, and has also commissioned similar research from IVO International, the Technical Research Centre of Finland (VTT) and from Tampere University of Technology. The research work strives to gain more in-depth knowledge on the phenomenon of frosting and its impact on corona losses. The correct prediction of frost helps reduce corona losses, while also cutting costs considerably. (orig.)

  11. 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

  12. Eddy current losses at cryogenic temperatures

    International Nuclear Information System (INIS)

    Sokolovsky, V.; Meerovich, V.; Slonim, M.

    1993-01-01

    The present paper analyses effect of thermal processes on eddy-current losses in construction elements of cryogenic and superconducting devices. Maxwell's equations coupled with heat-conduction equation are solved with taking into account the dependence of resistivity, heat capacity and heat-transfer coefficient on temperature. Analysis of losses as a function of magnetic field, frequency and geometry factors is given for the case of thin strip in a uniform magnetic field. It is shown that losses calculated with taking into account the thermal processes may differ from those obtained at constant temperature

  13. Heat loss from an open cavity

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  14. Weight Loss Surgery

    Science.gov (United States)

    Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you ... caused by obesity. There are different types of weight loss surgery. They often limit the amount of food ...

  15. Weight Loss & Acute Porphyria

    Science.gov (United States)

    ... APF You are here Home Diet and Nutrition Weight loss & acute Porphyria Being overweight is a particular problem ... one of these diseases before they enter a weight-loss program. Also, they should not participate in a ...

  16. Hearing Loss: Screening Newborns

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Hearing Loss Screening Newborns Past Issues / Spring 2015 Table of ... of newborns in the U.S. are screened for hearing loss before they leave the hospital. Research improves the ...

  17. Blindness and vision loss

    Science.gov (United States)

    ... life. Alternative Names Loss of vision; No light perception (NLP); Low vision; Vision loss and blindness Images ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  18. Recurrent pregnancy loss

    DEFF Research Database (Denmark)

    Egerup, Pia; Kolte, A M; Larsen, E C

    2016-01-01

    immunoglobulin (IvIg) conducted from 1991 to 2014. No other treatments were given. Patients with documented explained pregnancy losses (ectopic pregnancies and aneuploid miscarriages) were excluded. PARTICIPANTS/MATERIALS, SETTING, METHODS: Of the 168 patients included in the trials, 127 had secondary RPL......STUDY QUESTION: Is there a different prognostic impact for consecutive and non-consecutive early pregnancy losses in women with secondary recurrent pregnancy loss (RPL)? SUMMARY ANSWER: Only consecutive early pregnancy losses after the last birth have a statistically significant negative prognostic...... impact in women with secondary RPL. WHAT IS KNOWN ALREADY: The risk of a new pregnancy loss increases with the number of previous pregnancy losses in patients with RPL. Second trimester losses seem to exhibit a stronger negative impact than early losses. It is unknown whether the sequence of pregnancy...

  19. Genes and Hearing Loss

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Genes and Hearing Loss Genes and Hearing Loss Patient ... mutation may only have dystopia canthorum. How Do Genes Work? Genes are a road map for the ...

  20. Occupational hearing loss

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001048.htm Occupational hearing loss To use the sharing features on this page, please enable JavaScript. Occupational hearing loss is damage to the inner ear from noise ...

  1. Myopic loss aversion revisited

    OpenAIRE

    Blavatskyy, Pavlo; Pogrebna, Ganna

    2009-01-01

    In this paper we reexamine several experimental papers on myopic loss aversion by analyzing individual rather than aggregate choice patterns. We find that the behavior of the majority of subjects is inconsistent with the hypothesis of myopic loss aversion.

  2. Proven Weight Loss Methods

    Science.gov (United States)

    Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. ... limiting calories) usually isn’t enough to cause weight loss. But exercise plays an important part in helping ...

  3. Medicines and Bone Loss

    Science.gov (United States)

    Fact Sheet Medici a ne n s d Bone Loss Some types of medicines can cause bone loss, making your bones weak, if used for a long time. Use over a short time ... old bone and replaces it with new bone. Bone loss occurs when old bone breaks down faster than ...

  4. Female Pattern Hair Loss

    Science.gov (United States)

    ... Category: Share: Yes No, Keep Private Female Pattern Hair Loss Share | The most common type of hair loss seen in women is androgenetic alopecia, also ... men, it does not have to be complete hair loss. This is seen as hair thinning predominantly ...

  5. 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

  6. 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.

  7. Hearing Loss in Children: Types of Hearing Loss

    Science.gov (United States)

    ... hearing. There are four types of hearing loss: Conductive Hearing Loss Hearing loss caused by something that stops sounds ... Hearing Loss Hearing loss that includes both a conductive and a sensorineural hearing loss. Auditory Neuropathy Spectrum Disorder Hearing loss that occurs ...

  8. 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...

  9. Low-loss infrared fibers

    Science.gov (United States)

    Harrington, J. A.

    1980-12-01

    This final report describes research on low-loss fiber waveguides for use in future long-distance fiber links. The goal of the program is to develop non-oxide-containing fibers with losses as low as 10 to the minus 3rd power dB/km. This work is part of an overall technology assessment to determine the feasibility of fabricating such ultra low loss optical fibers. The approach being used to develop these very transparent waveguides is to fabricate fiber from IR transmitting crystalline materials. The materials studied were the alkali and thallium halides. We found that we could not successfully apply our extrusion technology, developed for the thallium halides, to fabricate alkali halide fibers. Extruded KCl or CsI fibers, for example, always had poor surface quality due to surface cracks (fish-scale appearance). We therefore abandoned extrusion methods for the alkali halides in favor of other fiber fabrication techniques. An alternative technique used was single crystal (SC) fiber growth. SC fibers represent a potentially ideal waveguide because they are free from mechanical defects (such as strain fields associated with grain boundaries in extruded polycrystalline fibers) and thus should have less scattering losses than polycrystalline waveguides. To make SC fibers we used an inverted Czochralski growth technique and applied the method to KC1. By the end of the program we had not yet produced any SC KCl fiber, but we expect to do so shortly.

  10. Variation in species composition and infection rates of Anopheles mosquitoes at different altitudinal transects, and the risk of malaria in the highland of Dirashe Woreda, south Ethiopia.

    Science.gov (United States)

    Daygena, Taye Yohannes; Massebo, Fekadu; Lindtjørn, Bernt

    2017-07-19

    The transmission of malaria is heterogeneous, and varies due to altitude. The information on whether the transmission of malaria is indigenous or imported to highland areas is scarce. Therefore, this study aimed to assess the species composition and infection rates of Anopheles at different altitudinal transects, and the risk of malaria if any in the highland of Dirashe Woreda, South Ethiopia. This study was conducted in Gato (low altitude; average elevation of 1273 m), Onota (mid-altitude; average elevation of 1707 m) and Layignaw-Arguba (high altitude; average elevation of 2337 m) from August 2015 to April 2016. Anopheles mosquitoes were sampled using Centers for Disease Control and Prevention (CDC) light traps from thirty houses (ten houses from each village). The circum-sporozoite proteins (CSPs) rate and entomological inoculation rate (EIR) of Anopheles mosquitoes were estimated. For the epidemiological survey, malaria cases were collected from laboratory registration books of selected health facilities from (August 2015-April 2016). A cross-sectional survey was done to collect data on malaria vector control activities in each village (August-September 2015). One thousand two hundred sixty-eight Anopheles mosquitoes comprising Anopheles arabiensis, An. demeilloni, An. cinereus, An. pharoensis, An. funestus-group, An. pretoriensis, An. christyi, An. ardensis and An. tenebrosus were identified in the study area. Anopheles arabiensis was the dominant species in Gato, whereas An. demeilloni was the dominant species in Layignaw-Arguba. Five mosquitoes, three An. arabiensis from Gato and two An. demeilloni from Layignaw-Arguba, were positive for Plasmodium falciparum CSPs. Plasmodium falciparum CSP rate was 0.4% (95% CI: 0.08-1.15) for An. arabiensis in Gato, and it was 0.64% (95% CI: 0.08-2.3) for An. demeilloni from Layignaw-Arguba. The P. falciparum EIR of An. arabiensis was 8.6 (95% CI: 2.4-33.4) infectious bites/person/nine-months in Gato. Plasmodium

  11. Handbook on loss reserving

    CERN Document Server

    Schmidt, Klaus; Schnaus, Anja

    2016-01-01

    This handbook presents the basic aspects of actuarial loss reserving. Besides the traditional methods, it also includes a description of more recent ones and a discussion of certain problems occurring in actuarial practice, like inflation, scarce data, large claims, slow loss development, the use of market statistics, the need for simulation techniques and the task of calculating best estimates and ranges of future losses. In property and casualty insurance the provisions for payment obligations from losses that have occurred but have not yet been settled usually constitute the largest item on the liabilities side of an insurer's balance sheet. For this reason, the determination and evaluation of these loss reserves is of considerable economic importance for every property and casualty insurer. Actuarial students, academics as well as practicing actuaries will benefit from this overview of the most important actuarial methods of loss reserving by developing an understanding of the underlying stochastic models...

  12. Global Hearing Loss Prevention.

    Science.gov (United States)

    Brown, Clifford Scott; Emmett, Susan D; Robler, Samantha Kleindienst; Tucci, Debara L

    2018-03-07

    Hearing loss is the fourth leading contributor to years lived with a disability worldwide. Most recent estimates indicate that one-half of a billion people suffer from disabling hearing loss worldwide. The social and economic burden is significant. When attributing monetary value to years lived with disability owing to hearing loss, there is greater than $US750 billion lost each year globally. There are numerous contributors to hearing loss, including congenital, infectious, noise exposure, age-related, traumatic, and immune-mediated causes. Understanding the pathophysiology of these factors allows for the development of preventative and treatment strategies specific to the underlying cause. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. 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.

  14. 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)

  15. Hearing Loss in Children

    Science.gov (United States)

    ... services to help you and your child. Language: English (US) Español (Spanish) Recommend on Facebook Tweet Share Compartir Hearing loss can affect a child’s ability to develop communication, language, and social skills. The earlier children with hearing loss start getting ...

  16. Loss muinasjuturaamatust / Agu Veetamm

    Index Scriptorium Estoniae

    Veetamm, Agu, 1953-

    2004-01-01

    Ballindaloch on üks väheseid Shoti losse, kus omanikud aastaringselt elavad. 450 aastat on loss kuulunud Macpherson-Grantide suguvõsale. Praegu on lossi omanikuks Clare Nancy Macpherson-Grant Russell, kelle kujundatud on kiviktaimla ja rosaarium. Lossi ajaloost, omanikest, ümberehitustest, ringkäigust lossis, pargist. 14 ill

  17. Hereditary Hearing Loss.

    Science.gov (United States)

    Tran, LenhAnh P.; Grundfast, Kenneth M.

    1997-01-01

    This article discusses inheritance patterns in hearing loss, epidemiology, clues to genetic causes, locating genes that cause hereditary disorders, genes related to hearing loss disorders in individuals with Usher syndrome, Waardenburg syndrome, Treacher-Collins syndrome, Branchio-oto-renal and Pendred syndromes, and the significance of finding…

  18. Help! It's Hair Loss!

    Science.gov (United States)

    ... Videos for Educators Search English Español Help! It's Hair Loss! KidsHealth / For Kids / Help! It's Hair Loss! ... is alopecia (say: al-uh-PEE-shuh). The Hair-y Story The hair on your head is ...

  19. Hearing Loss and Cytomegalovirus.

    Science.gov (United States)

    Strauss, Melvin

    1997-01-01

    Cytomegalovirus is the most common cause of congenital virally induced hearing loss. Maternal infection is most often asymptomatic as is the infection in the newborn. Hearing loss occurs in both clinically apparent infection and in the asymptomatic infection. Current methods of detection, treatment, and prevention and research efforts are…

  20. Concurrent credit portfolio losses.

    Science.gov (United States)

    Sicking, Joachim; Guhr, Thomas; Schäfer, Rudi

    2018-01-01

    We consider the problem of concurrent portfolio losses in two non-overlapping credit portfolios. In order to explore the full statistical dependence structure of such portfolio losses, we estimate their empirical pairwise copulas. Instead of a Gaussian dependence, we typically find a strong asymmetry in the copulas. Concurrent large portfolio losses are much more likely than small ones. Studying the dependences of these losses as a function of portfolio size, we moreover reveal that not only large portfolios of thousands of contracts, but also medium-sized and small ones with only a few dozens of contracts exhibit notable portfolio loss correlations. Anticipated idiosyncratic effects turn out to be negligible. These are troublesome insights not only for investors in structured fixed-income products, but particularly for the stability of the financial sector. JEL codes: C32, F34, G21, G32, H81.

  1. 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

  2. Loss aversion in schizophrenia.

    Science.gov (United States)

    Trémeau, Fabien; Brady, Melissa; Saccente, Erica; Moreno, Alexis; Epstein, Henry; Citrome, Leslie; Malaspina, Dolores; Javitt, Daniel

    2008-08-01

    Loss aversion in decision-making refers to a higher sensitivity to losses than to gains. Loss aversion is conceived as an affective interference in cognitive processes such as judgment and decision-making. Loss aversion in non-risky choices has not been studied in schizophrenia. Forty-two individuals with schizophrenia and 42 non-patient control subjects, matched by gender and age, were randomized to two different scenarios (a buying scenario and a selling scenario). Subjects were asked to evaluate the price of a decorated mug. Schizophrenia subjects were re-tested four weeks later with the other scenario. Contrary to non-patient controls, schizophrenia subjects did not show loss aversion. In the schizophrenia group, absence of loss aversion was correlated with age, duration of illness, number of months in State hospitals, and poorer performance in the Wisconsin Card Sorting Test, but not with current psychopathology and two domains of emotional experience. Absence of loss aversion in schizophrenia represents a deficit in the processing of emotional information during decision-making. It can be interpreted as a lack of integration between the emotional and the cognitive systems, or to a more diffuse and de-differentiated impact of emotional information on decision-making. Future studies should bring more clarity to this question.

  3. 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.

  4. Hearing loss and music

    Science.gov (United States)

    ... iPod or MP3 Player The small ear bud style headphones (inserted into the ears) DO NOT block ... chap 152. National Institute on Deafness and Other Communication Disorders. Noise-induced hearing loss. NIH Pub. No. ...

  5. Sudden Sensorineural Hearing Loss

    Science.gov (United States)

    Kuhn, Maggie; Heman-Ackah, Selena E.; Shaikh, Jamil A.

    2011-01-01

    Sudden sensorineural hearing loss (SSNHL) is commonly encountered in audiologic and otolaryngologic practice. SSNHL is most commonly defined as sensorineural hearing loss of 30dB or greater over at least three contiguous audiometric frequencies occurring within a 72-hr period. Although the differential for SSNHL is vast, for the majority of patients an etiologic factor is not identified. Treatment for SSNHL of known etiology is directed toward that agent, with poor hearing outcomes characteristic for discoverable etiologies that cause inner ear hair cell loss. Steroid therapy is the current mainstay of treatment of idiopathic SSNHL in the United States. The prognosis for hearing recovery for idiopathic SSNHL is dependent on a number of factors including the severity of hearing loss, age, presence of vertigo, and shape of the audiogram. PMID:21606048

  6. Financial Loss and Suicide

    OpenAIRE

    Saxby, Pridmore; Anil, Reddy

    2012-01-01

    The current Western psychiatric wisdom states that suicide is always or almost always associated with mental disorder. Careful Asian studies are casting doubt on this conclusion. Using information from the public record (newspapers, coroner’s reports, and various web-based sources), we sought evidence that, in the absence of mental disorder, suicide may be associated with major financial loss. Reports of 15 individuals who completed suicide following major financial loss were identified, thus...

  7. Lost: loss of chance.

    Science.gov (United States)

    Bird, Sara

    2010-09-01

    Loss of chance claims involve an allegation that a patient has lost the chance of a better medical outcome, in terms of treatment and/or prognosis, as a result of the negligence of the medical practitioner. A recent High Court of Australia judgment confirmed that monetary damages are not available for the loss of a chance of a better medical outcome. This article discusses the judgment and its implications for medical practitioners in Australia.

  8. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    İdil Ünal

    2014-06-01

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

  9. Atmosphere Impact Losses

    Science.gov (United States)

    Schlichting, Hilke E.; Mukhopadhyay, Sujoy

    2018-02-01

    Determining the origin of volatiles on terrestrial planets and quantifying atmospheric loss during planet formation is crucial for understanding the history and evolution of planetary atmospheres. Using geochemical observations of noble gases and major volatiles we determine what the present day inventory of volatiles tells us about the sources, the accretion process and the early differentiation of the Earth. We further quantify the key volatile loss mechanisms and the atmospheric loss history during Earth's formation. Volatiles were accreted throughout the Earth's formation, but Earth's early accretion history was volatile poor. Although nebular Ne and possible H in the deep mantle might be a fingerprint of this early accretion, most of the mantle does not remember this signature implying that volatile loss occurred during accretion. Present day geochemistry of volatiles shows no evidence of hydrodynamic escape as the isotopic compositions of most volatiles are chondritic. This suggests that atmospheric loss generated by impacts played a major role during Earth's formation. While many of the volatiles have chondritic isotopic ratios, their relative abundances are certainly not chondritic again suggesting volatile loss tied to impacts. Geochemical evidence of atmospheric loss comes from the {}3He/{}^{22}Ne, halogen ratios (e.g., F/Cl) and low H/N ratios. In addition, the geochemical ratios indicate that most of the water could have been delivered prior to the Moon forming impact and that the Moon forming impact did not drive off the ocean. Given the importance of impacts in determining the volatile budget of the Earth we examine the contributions to atmospheric loss from both small and large impacts. We find that atmospheric mass loss due to impacts can be characterized into three different regimes: 1) Giant Impacts, that create a strong shock transversing the whole planet and that can lead to atmospheric loss globally. 2) Large enough impactors (m_{cap} ≳ √{2

  10. Fenología del anillo de crecimiento de Pinus uncinata Ramond y Pinus sylvestris L. en un gradiente altitudinal en los Pirineos Centrales

    Directory of Open Access Journals (Sweden)

    Camarero, J. Julio

    1996-12-01

    Full Text Available In this study, we describe tree-ring growth and structure of Pinus uncinata Ram. and Pinus sylvestris L. along an altitudinal gradient in the Central Pyrenees. We measured monthly ring width increase and the number of cells added during 1993. Both species formed most of the ring from mid june to mid July 1993. Latewood development -formation, darkening and lignification of cell walls- starts in July and ends in October. The ring begins before its development in P. sylvestris than in P. uncinata that lives at higher elevation. P. uncinata formed narrower rings with less cells and greater color heterogeneity in the latewood than P. sylvestris. There is a high variability between trees in the earlywood and latewood cells position in the ring. The different phenological patterns of tree-ring growth along the selected altitudinal gradient could be partially explained by the influence of different climatic conditions, mainly thermic.

    [es] En el presente trabajo, describimos el desarrollo y la estructura del anillo anual de crecimiento de Pinus uncinata Ramondy Pinus sylvestris L. en un gradiente altitudinal en los Pirineos centrales. Medimos mensualmente el aumento de la anchura del anillo y el número de traqueidas añadidas a lo largo de 1993. En ambas especies, la mayor parte del anillo se forma desde mediados de jimio hasta mediados de julio de 1993. El desarrollo de la madera tardía -formación, coloración y engrasamiento y lignificación de las paredes celulares- comienza en julio y acaba en octubre. El anillo comienza antes su formación en los bosques estudiados de P. sylvestris que en P. uncinata, el cual vive a mayor altitud. P. uncinata forma anillos más estrechos, con menor múmero de células y con mayor heterogeneidad de color de la madera tardía que P. sylvestris. Existe una gran variabilidad entre árboles en la posición de las células de

  11. Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

    Science.gov (United States)

    Hamilton, H. B.; Strangas, E.

    1980-01-01

    The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

  12. Losses in Ferroelectric Materials

    Science.gov (United States)

    Liu, Gang; Zhang, Shujun; Jiang, Wenhua; Cao, Wenwu

    2015-01-01

    Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy

  13. Congenital sensorineural hearing loss

    International Nuclear Information System (INIS)

    Mafee, M.F.; Selis, J.E.; Yannias, D.A.; Valvassori, G.E.; Pruzansky, S.; Applebaum, E.L.; Capek, V.

    1984-01-01

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

  14. Congenital sensorineural hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Mafee, M.F.; Selis, J.E.; Yannias, D.A.; Valvassori, G.E.; Pruzansky, S.; Applebaum, E.L.; Capek, V.

    1984-02-01

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

  15. Weight Loss Nutritional Supplements

    Science.gov (United States)

    Eckerson, Joan M.

    Obesity has reached what may be considered epidemic proportions in the United States, not only for adults but for children. Because of the medical implications and health care costs associated with obesity, as well as the negative social and psychological impacts, many individuals turn to nonprescription nutritional weight loss supplements hoping for a quick fix, and the weight loss industry has responded by offering a variety of products that generates billions of dollars each year in sales. Most nutritional weight loss supplements are purported to work by increasing energy expenditure, modulating carbohydrate or fat metabolism, increasing satiety, inducing diuresis, or blocking fat absorption. To review the literally hundreds of nutritional weight loss supplements available on the market today is well beyond the scope of this chapter. Therefore, several of the most commonly used supplements were selected for critical review, and practical recommendations are provided based on the findings of well controlled, randomized clinical trials that examined their efficacy. In most cases, the nutritional supplements reviewed either elicited no meaningful effect or resulted in changes in body weight and composition that are similar to what occurs through a restricted diet and exercise program. Although there is some evidence to suggest that herbal forms of ephedrine, such as ma huang, combined with caffeine or caffeine and aspirin (i.e., ECA stack) is effective for inducing moderate weight loss in overweight adults, because of the recent ban on ephedra manufacturers must now use ephedra-free ingredients, such as bitter orange, which do not appear to be as effective. The dietary fiber, glucomannan, also appears to hold some promise as a possible treatment for weight loss, but other related forms of dietary fiber, including guar gum and psyllium, are ineffective.

  16. ECT and memory loss.

    Science.gov (United States)

    Squire, L R

    1977-09-01

    The author reviews several studies that clarify the nature of the memory loss associated with ECT. Bilateral ECT produced greater anterograde memory loss than right unilateral ECT and more extensive retrograde amnesia than unilateral ECT. Reactivating memories just before ECT did not produce amnesia. Capacity for new learning recovered substantially by several months after ECT, but memory complaints were common in individuals who had received bilateral ECT. Other things being equal, right unilateral ECT seems preferable to bilateral ECT because the risks to memory associated with unilateral ECT are smaller.

  17. Recurrent Pregnancy Loss

    Directory of Open Access Journals (Sweden)

    Véronique Piroux

    1997-01-01

    Full Text Available Antiphospholipid antibodies (APA are associated with thrombosis, thrombocytopenia and fetal loss but they occur in a variety of diseases. Despite many efforts, a correlation between the specificity of particular subgroups of APA and particular clinical situations remains to be established. The antigens at the origin of APA remain to be identified. We discuss here the possible links between cell apoptosis or necrosis, leading to plasma membrane alterations, and the occurrence of APA in response to sustained stimulation. The pathogenic potential of APA is also considered with respect to recurrent pregnancy loss.

  18. Determination of heat losses in the Cerro Prieto, Baja California, geothermal field steam transportation network based on the thermal insulation condition of the steam pipelines; Determinacion de perdidas de calor en la red de transporte de vapor del campo geotermico de Cerro Prieto, Baja California, con base en el estado fisico del aislamiento termico de vaporductos

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Garcia Gutierrez, Alfonso; Martinez Estrella, Juan Ignacio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; Canchola Felix, Ismael; Jacobo Galvan, Paul; Miranda Herrera, Carlos; Mora Perez, Othon [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)

    2011-07-15

    In Cerro Prieto Geothermal Field (CPGF), the steam from producing wells is transported to power plants through a large and complex system of pipes thermally insulated with a 2 inches thick mineral wool or a fiber glass layer and an external aluminum or iron cover. The insulation material has been exposed to weather conditions during the field operation and has suffered density and thickness changes. In some cases the insulation has been lost completely, increasing heat transfer from the pipes to the environment. This paper analyzes the impact of the conditions of thermal insulation on heat losses in the CPGF steam-pipeline network. The heat losses are calculated by applying an iterative method to determine the surface temperature based on a heat balance calculated from the three basic mechanisms of heat transfer: conduction, convection, and radiation. Finally, using length and diameter data corresponding to the condition of the thermal insulation of each pipeline-and field operation data, the overall heat losses are quantified for steam lines throughout the pipeline network in the field. The results allow us to evaluate the magnitude of the heat losses in comparison with the overall energy losses occurring during steam transport from wells to the power plants. [Spanish] En el Campo Geotermico de Cerro Prieto (CGCP), BC, el transporte de vapor desde los pozos hasta las plantas generadoras de electricidad se lleva a cabo mediante un extenso y complejo sistema de tuberias que tipicamente se encuentran aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion mecanica de aluminio o hierro galvanizado. Debido a la exposicion a las condiciones meteorologicas a traves del tiempo de operacion del campo, el aislamiento ha experimentado cambios en su densidad y espesor y en ocasiones se ha perdido por completo, lo cual repercute en una mayor transferencia de calor de las tuberias hacia el medio ambiente

  19. Side Effects: Hair Loss (Alopecia)

    Science.gov (United States)

    Hair loss, also called alopecia, is a side effect of cancer treatments, such as chemotherapy and radiation therapy. Learn how to cope with and manage hair loss. Listen to tips from others who have experienced hair loss.

  20. Heat loss from Buildings

    DEFF Research Database (Denmark)

    Karlsson, Kenneth; Næraa, Rikke

    1997-01-01

    Determination of heat loss coefficients for buildings in Denmark. The coefficient are determined for 15 building groups and 3 year intervals. They are based on the BBR-registre and assumptions of U-values(W/K*m2)and computed in a simple spreed sheet model.The results are used in the REVEILLE...

  1. Pregnancy Loss and Miscarriage

    Science.gov (United States)

    ... OC) Office of Global Health (OGH) Office of Health Equity (OHE) Office of Legislation and Public Policy (OLPP) Office of Science Policy, Reporting, and ... A miscarriage, also called pregnancy loss or spontaneous abortion, is the ... PubMed Health A.D.A.M. Medical Encyclopedia. (2010, November ...

  2. Responding to Amphibian Loss

    NARCIS (Netherlands)

    Mendelson III, J.R.; Lips, K.R.; Gagliardo, R.W.; Rabb, G.B.; Collins, J.P.; Diffendorfer, J.E.; Daszak, P.; Ibáñez D., R.; Zippel, K.C.; Lawson, D.P.; Wright, K.M.; Stuart, S.N.; Gascon, C.; da Silva, H.R.; Burrowes, P.A.; Joglar, R.L.; La Marca, E.; Lötters, S.; du Preez, L.H.; Weldon, C.; Hyatt, A.; Rodriguez-Mahecha, J.V.; Hunt, S.; Robertson, H.; Lock, B.; Raxworthy, C.J.; Frost, D.R.; Lacy, R.C.; Alford, R.A.; Campbell, J.A.; Parra-Olea, G.; Bolaños, F.; Calvo Domingo, J.J.; Halliday, T.; Murphy, J.B.; Wake, M.H.; Coloma, L.A.; Kuzmin, S.L.; Price, M.S.; Howell, K.M.; Lau, M.; Pethiyagoda, R.; Boone, M.; Lannoo, M.J.; Blaustein, A.R.; Dobson, A.; Griffiths, R.A.; Crump, M.L.; Wake, D.B.; Brodie Jr, E.D.

    2006-01-01

    In their Policy Forum "Confronting amphibian declines and extinctions" (7 July, p. 48), J. R. Mendelson III and colleagues offer a strategy for "stopping" the widespread losses of frogs, toads, and salamanders. Disease research and captive breeding figure prominently in their call for action.

  3. Biologicals and bone loss

    NARCIS (Netherlands)

    Krieckaert, C.L.M.; Lems, W.F.

    2012-01-01

    Inflammatory joint diseases are associated with extra-articular side effects including bone involvement.There is an increased risk of osteoporotic fractures. The pathogeneses of local and generalized bone loss share a common pathway. Early and active rheumatoid arthritis is associated with

  4. Menopause and Bone Loss

    Science.gov (United States)

    ... calcium supplement if necessary. • Vitamin D. Your body needs vitamin D to absorb calcium and move it into ... bone density test? • Should I take calcium and vitamin D supplements? How much do I need? • Do I need medication for my bone loss? • ...

  5. Ionization loss in BGO

    International Nuclear Information System (INIS)

    Bakken, J.A.; Denes, P.; Piroue, P.A.; Stickland, D.P.; Sumner, R.L.; Taylor, C.; Barone, L.; Borgia, B.; Diemoz, M.; Dionisi, C.; Falciano, S.; Ferroni, F.; Gratta, G.; Longo, E.; Luminari, L.; Morganti, S.; Valente, E.; Blaising, J.J.; Boutigny, D.; Coignet, G.; Karyotakis, Y.; Sauvage, G.; Schneegans, M.; Vivargent, M.; Extermann, P.; Morand, G.; Ossmann, J.; Ruckstuhl, W.; Schaad, T.P.; Lecoq, P.; Walk, W.; Li, P.J.; Micke, M.; Micke, U.; Schmitz, D.

    1988-01-01

    We report on a precise measurement of the energy loss through ionization by pions in bismuth germanate performed at several values of the incident particles momentum with a prototype of the L3 electromagnetic calorimeter. The experimental results are in good agreement with theoretical predictions showing the relativistic rise modified by density effect. (orig.)

  6. Deafness and Hearing Loss.

    Science.gov (United States)

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This brief overview provides information on the definition, incidence, and characteristics of children with hearing impairments and deafness. The federal definitions of hearing impairment and deafness are provided. The different types of hearing loss are noted, including: (1) conductive (caused by diseases or obstructions in the outer or middle…

  7. 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

  8. Soil loss prediction using universal soil loss equation (USLE ...

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... and still protect the underlying soil from wind and water erosion; and (3) the total soil volume as a reservoir for water and plant nutrients, which is preserved by minimizing soil loss. Erosion losses are estimated by the universal soil loss equation and the revised universal soil loss equation. The T factor is ...

  9. Visual field

    Science.gov (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  10. Enamel mineral loss.

    Science.gov (United States)

    West, Nicola X; Joiner, Andrew

    2014-06-01

    To summarise the chemical, biological and host factors that impact enamel mineral loss, to highlight approaches to contemporary management of clinical conditions involving mineral loss and summarise emerging trends and challenges in this area. "Medline" and "Scopus" databases were searched electronically with the principal key words tooth, enamel, *mineral*, caries and erosion. Language was restricted to English and original studies and reviews were included. Conference papers and abstracts were excluded. Enamel mineral loss leads to the degradation of the surface and subsurface structures of teeth. This can impact their shape, function, sensitivity and aesthetic qualities. Dental caries is a multifactorial disease caused by the simultaneous interplay of dietary sugars, dental plaque, the host and time. There is a steady decline in dental caries in developed countries and the clinical management of caries is moving towards a less invasive intervention, with risk assessment, prevention, control, restoration and recall. Tooth wear can be caused by erosion, abrasion and attrition. Dental erosion can be the result of acid from intrinsic sources, such as gastric acids, or extrinsic sources, in particular from the diet and consumption of acidic foods and drinks. Its prevalence is increasing and it increases with age. Clinical management requires diagnosis and risk assessment to understand the underlying aetiology, so that optimal preventative measures can be implemented. Overall, prevention of enamel mineral loss from caries and tooth wear should form the basis of lifelong dental management. Evidence based oral hygiene and dietary advice is imperative, alongside preventive therapy, to have a healthy lifestyle, whilst retaining hard tooth tissue. © 2014 Elsevier Ltd. All rights reserved.

  11. ADT fast losses MD

    CERN Document Server

    Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

    2013-01-01

    The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

  12. Theory of suppression of loss cone instabilities by electron beams

    International Nuclear Information System (INIS)

    Sinha, A.; Sinha, M.

    1981-01-01

    A new mechanism for the suppression of Drift Cyclotron Loss Cone instabilities by electron beams injected along the field lines is given. The mechanism explains some of the recent observations. (author)

  13. Loss aversion under prospect theory: A parameter-free measurement

    NARCIS (Netherlands)

    M. Abdellaoui (Mohammed); H. Bleichrodt (Han); 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

  14. Poems for Giving Life and Loss New Meaning

    Science.gov (United States)

    Roos, Susan

    2007-01-01

    The author reviews "Rainbow in the Stone: Selected Poems," by Robert A. Neimeyer, showing its relevance to the field of thanatology. Most applicable to "Death Studies" readers are the poems from the "Lessons of Loss" section which express the language of loss and deep emotion. The reviewer finds the poem "Visitor" most poignant in its description…

  15. 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

  16. 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…

  17. 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.

  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. Female pattern hair loss

    Directory of Open Access Journals (Sweden)

    Archana Singal

    2013-01-01

    Full Text Available Female pattern hair loss (FPHL is a common cause of hair loss in women characterized by diffuse reduction in hair density over the crown and frontal scalp with retention of the frontal hairline. Its prevalence increases with advancing age and is associated with significant psychological morbidity. The pathophysiology of FPHL is still not completely understood and seems to be multifactorial. Although androgens have been implicated, the involvement of androgen-independent mechanisms is evident from frequent lack of clinical or biochemical markers of hyperandrogenism in affected women. The role of genetic polymorphisms involving the androgen and estrogen receptors is being increasingly recognized in its causation and predicting treatment response to anti-androgens. There are different clinical patterns and classifications of FPHL, knowledge of which facilitates patient management and research. Chronic telogen effluvium remains as the most important differential diagnosis. Thorough history, clinical examination, and evaluation are essential to confirm diagnosis. Patients with clinical signs of androgen excess require assessment of biochemical parameters and imaging studies. It is prudent to screen the patients for metabolic syndrome and cardiovascular risk factors. The treatment comprises medical and/or surgical modalities. Medical treatment should be initiated early as it effectively arrests hair loss progression rather than stimulating regrowth. Minoxidil continues to be the first line therapy whereas anti-androgens form the second line of treatment. The progressive nature of FPHL mandates long-term treatment for sustained effect. Medical therapy may be supplemented with cosmetic concealment in those desirous of greater hair density. Surgery may be worthwhile in some carefully selected patients.

  20. 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.

  1. 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)

  2. Loss Aversion and Individual Characteristics

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Fosgerau, Mogens

    2011-01-01

    Many studies have shown that loss aversion affects the valuation of non-market goods. Using stated choice data, this paper presents an empirical investigation of how individual-level loss aversion varies with observable personal characteristics and with the choice context. We investigate loss...... aversion with respect to travel time and money, and find significant loss aversion in both dimensions. The degree of loss aversion in the time dimension is larger than in the money dimension, and depends on age and education. Subjects tend to be more loss averse when the reference is well established....

  3. Tragic loss at CERN

    CERN Multimedia

    CERN Ski Club

    2015-01-01

    Tragic loss at CERN The CERN community is mourning the tragic loss of two members of the CERN Ski Club. On Sunday, April 12, an avalanche buried four out of five skiers, taking part in a ski touring in the region of the Becs de Bosson in Valais (CH). The fifth skier, who had not been buried in the snow,  courageously managed to save two of the skiers, but Hervé Milcent, 49 years, federal ski instructor, and Mattieu Cattin, 33 years, were buried under two to three meters of snow, far down the avalanche slope, and did not survive, despite the fast arrival of the mountain rescue. In its 40 years of existence, the CERN Ski Club, one of the biggest in the Geneva area, has never been confronted with such a tragedy. The passing of Hervé and Matthieu has deeply shocked and saddened all volunteers of the Club as well as the entire alpine community. The ski touring section of the club would like to honour its friend Hervé, who joined the club in 1998. In 2003 he became res...

  4. Judged seriousness of environmental losses: reliability and cause of loss

    Science.gov (United States)

    Thomas C. Brown; Dawn Nannini; Robert B. Gorter; Paul A. Bell; George L. Peterson

    2002-01-01

    Public judgments of the seriousness of environmental losses were found to be internally consistent for most respondents, and largely unaffected by attempts to manipulate responses by altering the mix of losses being judged. Both findings enhance confidence in the feasibility of developing reliable rankings of the seriousness of environmental losses to aid resource...

  5. The osteoimmunology of alveolar bone loss.

    Science.gov (United States)

    Tompkins, Kevin A

    2016-01-01

    The mineralized structure of bone undergoes constant remodeling by the balanced actions of bone-producing osteoblasts and bone-resorbing osteoclasts (OCLs). Physiologic bone remodeling occurs in response to the body's need to respond to changes in electrolyte levels, or mechanical forces on bone. There are many pathological conditions, however, that cause an imbalance between bone production and resorption due to excessive OCL action that results in net bone loss. Situations involving chronic or acute inflammation are often associated with net bone loss, and research into understanding the mechanisms regulating this bone loss has led to the development of the field of osteoimmunology. It is now evident that the skeletal and immune systems are functionally linked and share common cells and signaling molecules. This review discusses the signaling system of immune cells and cytokines regulating aberrant OCL differentiation and activity. The role of these cells and cytokines in the bone loss occurring in periodontal disease (PD) (chronic inflammation) and orthodontic tooth movement (OTM) (acute inflammation) is then described. The review finishes with an exploration of the emerging role of Notch signaling in the development of the immune cells and OCLs that are involved in osteoimmunological bone loss and the research into Notch signaling in OTM and PD.

  6. AC loss characteristics of CORC® cable with a Cu former

    Science.gov (United States)

    Terzioğlu, R.; Vojenčiak, M.; Sheng, J.; Gömöry, F.; Çavuş, T. F.; Belenli, İ.

    2017-08-01

    High-temperature superconductors from the REBCO (RE = rare earth) family have attained industrial production and their performance is continuously being enhanced. However, cabling technology for high-current (kA range) cables for magnet technology is still challenging and there are only few cable concepts available (CORC®, Roebel cable, twisted stack cable). Each of them exhibits different characteristics. In this paper we experimentally investigate CORC® cable produced in-house utilizing a copper tube former. Such a former offers a central cooling channel for partial or complete cable cooling by forced flow of coolant. We focus mainly on AC loss due to transporting AC current, an external applied AC magnetic field and their simultaneous action. In the case of transporting AC current we found indications that a large part of the total loss has its origin in eddy currents due to an axial magnetic field. For the investigation of magnetization AC loss, we prepared several samples with different configurations. In this case we found direct evidence for increasing AC loss due to losses in the metallic former. However, we also found that at low field amplitudes the magnetization AC loss of the complete cable is lower than the loss in the bare former. This is caused by shielding of the magnetic field by a superconductor, which was also confirmed by numerical simulations.

  7. Breast Cancer and Bone Loss

    Science.gov (United States)

    ... Menopause Map Featured Resource Find an Endocrinologist Search Breast Cancer and Bone Loss July 2010 Download PDFs English ... G. Komen Foundation What is the link between breast cancer and bone loss? Certain treatments for breast cancer ...

  8. Overweight, Obesity, and Weight Loss

    Science.gov (United States)

    ... Back to section menu Healthy Weight Weight and obesity Underweight Weight, fertility, and pregnancy Weight loss and ... section Home Healthy Weight Healthy Weight Weight and obesity Underweight Weight, fertility, and pregnancy Weight loss and ...

  9. Antithrombotic therapy for pregnancy loss

    NARCIS (Netherlands)

    de Jong, Paulien G.; Goddijn, Mariëtte; Middeldorp, Saskia

    2013-01-01

    BACKGROUND Although an association between thrombophilia and pregnancy loss has been observed in many studies, little is known about the pathophysiological mechanisms behind this association. Considering the association between thrombophilia and pregnancy loss, the efficacy of antithrombotic therapy

  10. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is ... I find additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound ...

  11. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... message, please visit this page: About CDC.gov . NOISE AND HEARING LOSS PREVENTION Language: English (US) Español ( ... when hazardous noise levels cannot be adequately reduced. Noise and Hearing Loss on the NIOSH Science Blog ...

  12. Phase Field

    Science.gov (United States)

    Koyama, Toshiyuki

    The term phase field has recently become known across many fields of materials science. The meaning of phase field is the spatial and temporal order parameter field defined in a continuum-diffused interface model. By using the phase field order parameters, many types of complex microstructure changes observed in materials science are described effectively. This methodology has been referred to as the phase field method, phase field simulation, phase field modeling, phase field approach, etc. In this chapter, the basic concept and theoretical background for the phase field approach is explained in Sects. 21.1 and 21.2. The overview of recent applications of the phase field method is demonstrated in Sects. 21.3 to 21.6.

  13. Mass Loss from Betelgeuse

    Science.gov (United States)

    Richards, A. M. S.

    2013-05-01

    Betelgeuse is just starting to produce a wind which is thick enough to form dust. However, the grains seem to coalesce at much greater distances than those in "dust-driven" winds from later-stage AGB and RSG stars. Is the mass loss mechanism different, and how will it evolve? We know a great deal about the kinematics of the more evolved winds, thanks to sub-au imaging using masers, and easily-resolved CO shells, but Betelgeuse is a much fainter target, only resolved with great difficulty (although ALMA will change that). On the other hand, Betelgeuse was the first star other than the Sun to be imaged in detail in the radio as well as optical. Radio studies from the photosphere to the astropause will reveal: How is mass lost from the stellar surface? In what form is this returned to the ISM? These results could even help to answer: How will Betelgeuse evolve in the next few millennia?

  14. Losses compensation; Compensation des pertes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    One mission of RTE (Electric Power Transportation), is to watch over the losses compensation resulting from the power transport on the electric power network. Since january 2001, RTE makes good the electric losses by the purchase of energy. To choose the marketers, a consultation has been realized by RTE. This document presents the rules concerning these losses compensation. (A.L.B.)

  15. Quantification of surgical blood loss.

    Science.gov (United States)

    Lee, Marcel H; Ingvertsen, Britt T; Kirpensteijn, Jolle; Jensen, Asger L; Kristensen, Annemarie T

    2006-06-01

    To compare gravimetric and colorimetric methods of quantifying surgical blood loss, and to determine if there is a correlation between preoperative hemostatic tests (buccal mucosa bleeding time [BMBT] and intraoperative blood loss). Prospective clinical study. Dogs (n=15) admitted for cutaneous tumor excision, orthopedic procedure, or exploratory laparotomy. Intraoperative blood loss was quantified by measuring irrigation fluid and weighing surgical sponges used for blood and fluid collection during surgery. Results of gravimetric measurements were then correlated to blood loss quantified using spectrophotometric analysis of hemoglobin (Hb) content. Hemostatic variables including BMBT were measured before surgery and compared with the calculated amount of blood loss. Blood loss quantified by gravimetric measurement showed a significant correlation with colorimetric determination of Hb content in surgical sponges and collected irrigation fluid (r=0.93, P<.0001). BMBT correlated weakly but significantly with intraoperative blood loss (r=0.56, P<.05). Quantifying intraoperative blood loss using spectrophotometric Hb analysis accurately assessed the amount of blood loss; however, it is a time-consuming procedure, primarily applicable as a research tool. Gravimetric evaluation of intraoperative blood loss was found to be an accurate method, which can be recommended for use in a clinical setting. Estimation of blood loss using a gravimetric method is accurate and applicable in the clinical setting and provides surgeons with a simple and objective tool to evaluate intraoperative blood loss.

  16. Hypnotherapy in Weight Loss Treatment.

    Science.gov (United States)

    Cochrane, Gordon; Friesen, John

    1986-01-01

    Investigated effects of hypnosis as a treatment for weight loss among women. The primary hypothesis that hypnosis is an effective treatment for weight loss was confirmed, but seven concomitant variables and the use of audiotapes were not significant contributors to weight loss. (Author/ABB)

  17. AC loss in a high-temperature superconducting coil

    NARCIS (Netherlands)

    Chevtchenko, O.A.; Rabbers, J.J.; Godeke, A.; ten Haken, Bernard; ten Kate, Herman H.J.

    1998-01-01

    In a typical superconducting coil made of BSCCO/Ag tape, both amplitude and direction of the magnetic field determine the critical current, resistive voltage and AC loss. The distribution of the magnetic field along and across the superconducting tape in a coil is rather complex. This gives rise to

  18. Heat losses estimation associated with the physical state of the thermal insulation of pipes vaporductos network in Cerro Prieto geothermal field; Estimacion de perdidas de calor asociadas al estado fisico del aislamiento termico de las tuberias de la red de vaporductos del campo geotermico Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Martinez Estrella, Juan Ignacio; Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; jime@iie.org.mx; aggarcia@iie.org.mx; Canchola Felix, Ismael; Miranda Herrera, Carlos; Jacobo Galvan, Paul [Campo Geotermico de Cerro Prieto, Comision Federal de Electricidad, Mexicali, B.C. (Mexico)

    2010-11-15

    The Cerro Prieto Geothermal Field (CPGF) steam transportation network is constituted by 140 km of pipes with diameters ranging from 8 to 48 inches, which transport the steam of 165 producing wells to 13 power plants which have a total installed capacity of 720 MWe. Originally, the pipes are thermally insulated with a mineral wool or fiber glass layer and an external aluminum or iron cover. Due to the insulation material has been exposed to weather conditions during the field operation it shows nowadays different grades of wear-out, or even it is lacking in some parts of the network, causing higher heat losses from the pipes to the environment. In this work, the magnitude of the heat losses related with the present condition of the thermal insulation throughout the pipeline network is assessed. This involved determining the longitude and diameter, as well as the insulation condition of each single pipeline section, and the calculation of the heat transfer coefficients for the different thermal insulation conditions defined for this study. [Spanish] La red de transporte de vapor del campo geotermico Cerro Prieto (CGCP) esta constituida por aproximadamente 140 km de tuberias de 8 a 48 pulgadas de diametro, las cuales conducen el vapor producido por 165 pozos hacia 13 plantas generadoras, cuya capacidad instalada es de 720 MWe. Originalmente, estas tuberias son aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion exterior de aluminio o hierro. Debido principalmente al impacto de las condiciones meteorologicas durante el tiempo de operacion del campo, en algunas porciones de la red el aislante presenta actualmente distintos grados de deterioro, o incluso se encuentra ausente, lo cual se traduce en una mayor perdida de calor desde las tuberias hacia el medio ambiente. En el presente trabajo se evalua la magnitud de las perdidas de calor asociadas al estado fisico del aislamiento termico de las

  19. 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.

  20. 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.

  1. Research on the Superposition of Harmonic Loss Considering Skin Effect

    Science.gov (United States)

    Jiang, Li-Min; Yan, Hua-Guang; Meng, Jun-Xia; Yin, Zhong-Dong; Lin, Zhi

    2017-05-01

    Power system harmonic will cause extra power loss. The higher the harmonic order, the more obvious the skin effect, which means current density becomes larger near the surface of conductor. When several harmonics with different frequency exist, whether the current density distribution of each harmonic is independent, and whether the total harmonic loss can be regarded as the sum of each harmonic loss, need further research. In this paper, based on the basic principle of electromagnetic field, the expressions of the current density distribution and power loss under multiple harmonics background are deduced, and the superposition of harmonic loss considering skin effect is also proved, which can provide theory basis of harmonic loss calculation.

  2. Sensorineural hearing loss in children.

    LENUS (Irish Health Repository)

    Wormald, R

    2010-02-01

    The objective of the study was to examine the aetiology of sensorineural hearing loss (SNHL) in a paediatric population presenting to the National Centre of Medical Genetics. A retrospective chart review from 1998 to 2006. One hundred and twenty nine children were investigated for SNHL. The average age of diagnosis of hearing loss was 36 months. The degree of hearing loss was mild in 8 children, moderate in 33 children, severe in 31 children and profound in 57 children. Eighty-five children (66%) were diagnosed with a hereditary hearing loss, 11 (8%) children had an acquired hearing loss and no cause found in 33 (26%) children. This is the first report of the causes of hearing loss in Irish children. The mean age of diagnosis in our cohort is high and emphasises the need for a neonatal screening programme. There remains a number of children for whom the cause of hearing loss remains unknown.

  3. Earthquake Loss Estimation Uncertainties

    Science.gov (United States)

    Frolova, Nina; Bonnin, Jean; Larionov, Valery; Ugarov, Aleksander

    2013-04-01

    The paper addresses the reliability issues of strong earthquakes loss assessment following strong earthquakes with worldwide Systems' application in emergency mode. Timely and correct action just after an event can result in significant benefits in saving lives. In this case the information about possible damage and expected number of casualties is very critical for taking decision about search, rescue operations and offering humanitarian assistance. Such rough information may be provided by, first of all, global systems, in emergency mode. The experience of earthquakes disasters in different earthquake-prone countries shows that the officials who are in charge of emergency response at national and international levels are often lacking prompt and reliable information on the disaster scope. Uncertainties on the parameters used in the estimation process are numerous and large: knowledge about physical phenomena and uncertainties on the parameters used to describe them; global adequacy of modeling techniques to the actual physical phenomena; actual distribution of population at risk at the very time of the shaking (with respect to immediate threat: buildings or the like); knowledge about the source of shaking, etc. Needless to be a sharp specialist to understand, for example, that the way a given building responds to a given shaking obeys mechanical laws which are poorly known (if not out of the reach of engineers for a large portion of the building stock); if a carefully engineered modern building is approximately predictable, this is far not the case for older buildings which make up the bulk of inhabited buildings. The way population, inside the buildings at the time of shaking, is affected by the physical damage caused to the buildings is not precisely known, by far. The paper analyzes the influence of uncertainties in strong event parameters determination by Alert Seismological Surveys, of simulation models used at all stages from, estimating shaking intensity

  4. Optimization of fuel cycles: marginal loss values

    International Nuclear Information System (INIS)

    Gaussens, J.; Lasteyrie, B. de; Doumerc, J.

    1965-01-01

    Uranium processing from the pit to the fuel element rod entails metal losses at every step. These losses become more and more expensive with the elaboration of the metal. Some of the uranium must be accepted as definitely lost whilst the rest could be recovered and recycled. The high cost of these losses, whether they are recycled or not, and the fact that the higher the enrichment is the higher their costs are, make it necessary to take them into account when optimizing fuel cycles. It is therefore felt important to determine their most desirable level from an economic point of view at the various nuclear fuel processing stages. However, in France as in some other countries, fissile material production is a state concern, whilst fuel element fabrication is carried out by private enterprise. Optimization criteria and the economic value of losses are therefore different for each of the two links in the fabrication chain. One can try in spite of this to reach an optimum which would conform to public interest, without interfering with the firm's sales policy. This entails using the fact that for a given output marginal costs are equal at the optimum. One can therefore adjust the level of the losses to attain this equation of marginal costs, as these are easier to obtain from the firm than a justification of the actual prices. One notices moreover that, although mainly concerned with losses, this global analysis can bring both the state and the firm to a better use of other production factors. An account is given of the theory of this economic optimization method and practical applications in the field of natural uranium-graphite moderated and CO 2 cooled reactor fuel element fabrication are offered. (authors) [fr

  5. Atom trap loss, elastic collisions, and technology

    Science.gov (United States)

    Booth, James

    2012-10-01

    The study of collisions and scattering has been one of the most productive approaches for modern physics, illuminating the fundamental structure of crystals, surfaces, atoms, and sub-atomic particles. In the field of cold atoms, this is no less true: studies of cold atom collisions were essential to the production of quantum degenerate matter, the formation of cold molecules, and so on. Over the past few years it has been my delight to investigate elastic collisions between cold atoms trapped in either a magneto-optical trap (MOT) or a magnetic trap with hot, background gas in the vacuum environment through the measurement of the loss of atoms from the trap. Motivated by the goal of creating cold atom-based technology, we are deciphering what the trapped atoms are communicating about their environment through the observed loss rate. These measurements have the advantages of being straightforward to implement and they provide information about the underlying, fundamental inter-atomic processes. In this talk I will present some of our recent work, including the observation of the trap depth dependence on loss rate for argon-rubidium collisions. The data follow the computed loss rate curve based on the long-range Van der Waals interaction between the two species. The implications of these findings are exciting: trap depths can be determined from the trap loss measurement under controlled background density conditions; observation of trap loss rate in comparison to models for elastic, inelastic, and chemical processes can lead to improved understanding and characterization of these fundamental interactions; finally the marriage of cold atoms with collision modeling offers the promise of creating a novel pressure sensor and pressure standard for the high and ultra-high vacuum regime.

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

    Science.gov (United States)

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

    2016-01-01

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

  7. Pattern of glaucomatous neuroretinal rim loss.

    Science.gov (United States)

    Jonas, J B; Fernández, M C; Stürmer, J

    1993-01-01

    In advancing glaucomatous optic nerve damage, the area of the neuroretinal rim progressively diminishes, and its form continuously changes. This cross-sectional study was undertaken to establish a set pattern behind glaucomatous rim loss. The authors evaluated morphometrically stereo color optic disc photographs of 801 glaucomatous eyes and 496 visually normal eyes. Compared with the visually normal eyes, glaucomatous neuroretinal rim loss occurred in all sectors of the optic disc with regional preferences depending on the stage of the disease. In the eyes with modest glaucomatous damage, rim loss was usually most pronounced in the inferotemporal disc region. In the eyes with moderately progressed glaucomatous changes, rim was decreased most markedly in the superotemporal sector, then in the temporal horizontal area, the nasal inferior region, and finally in the superior nasal sector. In very advanced glaucoma, rim remnants usually were present only in the nasal disc region. At that stage, they were significantly larger in the superior nasal region than in the nasal inferior area. Other than occurring in a diffuse way, glaucomatous neuroretinal rim loss took place in a sequence of sectors. Generally, it began in the inferotemporal disc region and then progressed to the superotemporal, the temporal horizontal, the inferior nasal, and finally the superior nasal sectors. This correlates with the progression of visual field defects and the morphology of the lamina cribrosa. This finding may be important for "early" glaucoma diagnosis.

  8. 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

  9. 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.

  10. Simulations of inner radiation belt proton loss during geomagnetic storms

    Science.gov (United States)

    Engel, M. A.; Kress, B. T.; Hudson, M. K.; Selesnick, R. S.

    2015-11-01

    The loss of protons in the outer part of the inner radiation belt (L = 2 to 3) during the 6 April 2000 solar energetic particles event has been investigated using test particle simulations that follow full Lorentz trajectories with both magnetic and electric fields calculated from an empirical model. The electric fields are calculated as inductive fields generated by the time-changing magnetic field, which is achieved by time stepping analytic magnetic fields. The simulation results are compared with proton measurements from the highly elliptical orbit satellite for three different energy ranges (8.5-35 MeV, 16-40 MeV, and 27-45 MeV) as well as previous modeling work done. In previous work, inner zone radiation belt loss during geomagnetic storms has been modeled by simulating field line curvature scattering in static magnetic field snapshots with no electric field. The inclusion of the inductive electric field causes an increase in loss to lower L shells, improving the agreement with the satellite data.

  11. Magnetic Fields

    OpenAIRE

    Schöller, Markus; Hubrig, Swetlana

    2015-01-01

    In this chapter, we give a brief introduction into the use of the Zeeman effect in astronomy and the general detection of magnetic fields in stars, concentrating on the use of FORS2 for longitudinal magnetic field measurements.

  12. Occupational Hearing Loss in Korea

    OpenAIRE

    Kim, Kyoo Sang

    2010-01-01

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

  13. Estimated Blood Loss in Craniotomy

    OpenAIRE

    Sitohang, Diana; AM, Rachmawati; Arif, Mansyur

    2016-01-01

    Introduction: Estimated blood loss is an estimation of how much blood is loss during surgery. Surgical procedure requires a preparation of blood stock, but the demand for blood often larger than the actual blood used. This predicament happens because there is no blood requirement protocol being used. This study aims to determine the estimated blood loss during craniotomy procedure and it's conformity to blood units ordered for craniotomy procedure. Methods: This study is a retrospective study...

  14. Scannerless laser range imaging using loss modulation

    Science.gov (United States)

    Sandusky, John V [Albuquerque, NM

    2011-08-09

    A scannerless 3-D imaging apparatus is disclosed which utilizes an amplitude modulated cw light source to illuminate a field of view containing a target of interest. Backscattered light from the target is passed through one or more loss modulators which are modulated at the same frequency as the light source, but with a phase delay .delta. which can be fixed or variable. The backscattered light is demodulated by the loss modulator and detected with a CCD, CMOS or focal plane array (FPA) detector to construct a 3-D image of the target. The scannerless 3-D imaging apparatus, which can operate in the eye-safe wavelength region 1.4-1.7 .mu.m and which can be constructed as a flash LADAR, has applications for vehicle collision avoidance, autonomous rendezvous and docking, robotic vision, industrial inspection and measurement, 3-D cameras, and facial recognition.

  15. 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.

  16. Computation of loss allocation in electric power networks using loss ...

    African Journals Online (AJOL)

    This paper presents the computation of loss allocation that can be applied to sellers and buyers participating in electric power trade in a deregulated power market. The approach is based on the Jacobian and Hessian matrices of the power flow equations. The losses to be allocated are derived from load flow of a specified ...

  17. 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.)

  18. Altitudinal variation and bio-climatic variables influencing the potential distribution of Culicoides orientalis Macfie, 1932, suspected vector of Bluetongue virus across the North Eastern Himalayan belt of Sikkim.

    Science.gov (United States)

    Mukhopadhyay, Emon; Hazra, Surajit; Saha, Goutam Kumar; Banerjee, Dhriti

    2017-12-01

    Culicoides orientalis was first recorded from Sikkim, in the year 1963, but no evidence based disease outbreak were available. In the last 50 years, 260 Bluetongue disease outbreaks caused by Culicoides species have been evidenced from India. Moreover, in recent years with increase of average temperature worldwide and increase in longevity of arthropod vectors like Culicoides along with a geographical range shift to new suitable warmer regions has increased the potentiality of vector borne disease outbreak throughout the world. The Himalayan range of Sikkim in India is a biodiversity hotspot and is extremely sensitive to such global climate changes. An attempt has been made to evaluate the altitude, climate and environmental data on selected study sites of Sikkim for a period of two years (2014-2015) for discerning potential distribution of C.orientalis in this region. The altitude, temperature, precipitation and potential distribution range maps of C. orientalis showed the areas of highest species abundance within the altitudinal range of 550-1830m, with some species extending its range up to 3750m, with average precipitation of 2010-2590mm and mean temperature of 11-18°C. The Maximum Entropy Modelling (MaxEnt) and the Jackknife test of the MaxEnt model further revealed that the major contributing factors governing C. orientalis distribution are annual precipitation (78.8%), followed by precipitation of driest quarter (8.3%) and mean temperature of the warmest quarter (3.3%). Accuracy of the study was evaluated by the area under the curve (AUC=0.860). The Biplot on F 1 -F 2 axes (N=16, α=0.05) in the PCA showed the linear depiction of all the variables considered in our study, major contributors were annual precipitation, precipitation of driest quarter and mean temperature of warmest quarter being the primary factors governing species distribution, as analogous to results of the MaxEnt model. This study would help in developing strategies for monitoring and

  19. Detecting latitudinal and altitudinal expansion of invasive bamboo Phyllostachys edulis and Phyllostachys bambusoides (Poaceae) in Japan to project potential habitats under 1.5°C-4.0°C global warming.

    Science.gov (United States)

    Takano, Kohei Takenaka; Hibino, Kenshi; Numata, Ayaka; Oguro, Michio; Aiba, Masahiro; Shiogama, Hideo; Takayabu, Izuru; Nakashizuka, Tohru

    2017-12-01

    Rapid expansion of exotic bamboos has lowered species diversity in Japan's ecosystems by hampering native plant growth. The invasive potential of bamboo, facilitated by global warming, may also affect other countries with developing bamboo industries. We examined past (1975-1980) and recent (2012) distributions of major exotic bamboos ( Phyllostachys edulis and P. bambusoides ) in areas adjacent to 145 weather stations in central and northern Japan. Bamboo stands have been established at 17 sites along the latitudinal and altitudinal distributional limit during the last three decades. Ecological niche modeling indicated that temperature had a strong influence on bamboo distribution. Using mean annual temperature and sun radiation data, we reproduced bamboo distribution (accuracy = 0.93 and AUC (area under the receiver operating characteristic curve) = 0.92). These results infer that exotic bamboo distribution has shifted northward and upslope, in association with recent climate warming. Then, we simulated future climate data and projected the climate change impact on the potential habitat distribution of invasive bamboos under different temperature increases (i.e., 1.5°C, 2.0°C, 3.0°C, and 4.0°C) relative to the preindustrial period. Potential habitats in central and northern Japan were estimated to increase from 35% under the current climate (1980-2000) to 46%-48%, 51%-54%, 61%-67%, and 77%-83% under 1.5°C, 2.0°C, 3.0°C, and 4.0°C warming levels, respectively. These infer that the risk areas can increase by 1.3 times even under a 1.5°C scenario and expand by 2.3 times under a 4.0°C scenario. For sustainable ecosystem management, both mitigation and adaptation are necessary: bamboo planting must be carefully monitored in predicted potential habitats, which covers most of Japan.

  20. Understanding the effects of end-loss on linear Fresnelcollectors

    Science.gov (United States)

    Ma, Jing; Chang, Zheng

    2018-02-01

    In this paper, the end loss effect of linear Fresnel collector was analyzed. The aim of this work was to investigate the seasonal effects of end losses on the linear Fresnel collectors deployed, and analyze the change of the month average for end loss at different locations. Furthermore, a end loss compensated approach is proposed, and the increased instantaneous thermal efficiency of the experimental system is measured. A two-meter long linear Fresnel collector experimental system with horizontal north-south axis is performed, The result that compensation of the end loss of the linear Fresnel reflector system stands a good improvement for thermal performance. Meanwhile, in comparison with the reflector field prior to the change, an instantaneous thermal efficiency has increased by approximately 50%, and it increased by almost 20% at the afternoon time. All this work can offer some valuable references to the further study on high-efficiency linear Fresnel concentrating system.

  1. Measurement of AC losses in different former materials

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa

    1998-01-01

    A high temperature superconducting cable may be based on a centrally located cylindrical support, a so-called former. If electrically conductive, the former can contribute to the AC losses through eddy current losses caused by unbalanced axial and tangential magnetic fields. With these measurements...... we aim at investigating the eddy current losses of commonly used former materials. A one layer cable conductor was wound on a glass fibre reinforced polymer (GRFP) former. By inserting a variety of materials into this, it was possible to measure the eddy current losses of each of the former...... candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible...

  2. Calibration free method for measurement of the AC magnetization loss

    Energy Technology Data Exchange (ETDEWEB)

    Souc, Jan [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 842 39 Bratislava (Slovakia); Goemoery, Fedor [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 842 39 Bratislava (Slovakia); Vojenciak, Michal [Department of Power Electrical Systems, University of Zilina, Vel' ky diel, 010 26 Zilina (Slovakia)

    2005-05-01

    A calibration free measurement method for determination of the magnetization loss of superconducting samples exposed to the external AC magnetic field is presented. The idea is based on the measurement of the part of the power which is supplied by the AC source to the AC magnet generating the magnetic field, in which the sample is located. It uses a coil wound in parallel to the AC field magnet as the measurement coil. To achieve the necessary sensitivity, two identical systems are used, each consisting of an AC magnet and a measurement coil, one of them containing the sample and the other left empty. No measurement and/or calculation of the calibration constant is required. To confirm the suitability of this method, the loss of a Cu sample with known dissipation was measured. The applicability to the AC magnetization loss measurements of superconducting tapes is presented.

  3. Nature's loss, Immunologists gain?

    Science.gov (United States)

    Aluvihare

    2000-01-01

    Nature Reviews Molecular Cell Biology Nature Publishing Group (2000). ISSN 1471-0072. Monthly First there was Annual Reviews, then came the monthly Elsevier Trends Journals, both of which try to identify hot topics in their chosen fields. The Current Opinion journals followed several years later, and Current Opinion in Cell Biology is presently one of the highest 'impact factor' review journals, with a distinguished board of editors and advisors and a systematic approach to regular coverage of the major fields of cell biology. Important topics are visited once a year, whether or not something specially exciting happened in the last 12 months. Add to this list Seminars in Cell and Developmental Biology, the FASEB journal and the countless minireviews in 'real' journals, and you begin to wonder how anyone finds any time for doing experiments, or indeed reading the primary literature. So, into this already crowded field arrive three important newcomers: Nature Reviews in Molecular Cell Biology, Genetics, and Neurosciences, of which the first two will probably interest readers of Journal of Cell Science the most. Backed by the name and money of Nature and edited by experienced Nature staff, it is hard to see how these publications can possibly do other than succeed with writers and readers alike. What's inside the first issue? The cover of Nature Reviews in Molecular Cell Biology presents a 3-colour montage of a blue cell nucleus surrounded by splotches of green GPI-anchored GFP overlaid by orange actin stress fibres that seem to come from somewhere else. This image trails a comprehensive review from Kai Simons and Derek Toomre about Lipid Rafts. There are another five major review articles: calcium puffs and sparks, rings around DNA, HIV inhibitors, kinesin and the circadian clock provide a rich and varied mix of topics from authors who know what they're talking about. Surrounding this core is an entertaining mixture of 'highlights' at the front: news and views about

  4. Dietary Supplements for Weight Loss

    Science.gov (United States)

    Dietary Supplements for Weight Loss Fact Sheet for Consumers If you’re thinking about taking a dietary supplement to lose weight, talk with your health care provider. What are weight-loss dietary supplements and what do they do? The ...

  5. The Stigma of Hearing Loss

    Science.gov (United States)

    Wallhagen, Margaret I.

    2010-01-01

    Purpose: To explore dimensions of stigma experienced by older adults with hearing loss and those with whom they frequently communicate to target interventions promoting engagement and positive aging. Design and Methods: This longitudinal qualitative study conducted interviews over 1 year with dyads where one partner had hearing loss. Participants…

  6. World offshore energy loss statistics

    International Nuclear Information System (INIS)

    Kaiser, Mark J.

    2007-01-01

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

  7. Genes and Syndromic Hearing Loss.

    Science.gov (United States)

    Keats, Bronya J. B.

    2002-01-01

    This article provides a description of the human genome and patterns of inheritance and discusses genes that are associated with some of the syndromes for which hearing loss is a common finding, including: Waardenburg, Stickler, Jervell and Lange-Neilsen, Usher, Alport, mitochondrial encephalomyopathy, and sensorineural hearing loss. (Contains…

  8. An Index of Loss Aversion

    NARCIS (Netherlands)

    V. Köbberling (Veronika); P.P. Wakker (Peter)

    2005-01-01

    textabstractTo a considerable extent, risk aversion as it is commonly observed is caused by loss aversion. Several indexes of loss aversion have been proposed in the literature. The one proposed in this paper leads to a clear decomposition of risk attitude into three distinct components: basic

  9. An Index of Loss Aversion

    NARCIS (Netherlands)

    Köbberling, V.; Wakker, P.P.

    2005-01-01

    To a considerable extent, risk aversion as it is commonly observed is caused by loss aversion. Several indexes of loss aversion have been proposed in the literature. The one proposed in this paper leads to a clear decomposition of risk attitude into three distinct components: basic utility,

  10. Alzheimer's disease due to loss of function

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2016-01-01

    Alzheimer's Disease (AD) is a highly complex disease involving a broad range of clinical, cellular, and biochemical manifestations that are currently not understood in combination. This has led to many views of AD, e.g. the amyloid, tau, presenilin, oxidative stress, and metal hypotheses....... The amyloid hypothesis has dominated the field with its assumption that buildup of pathogenic β-amyloid (Aβ) peptide causes disease. This paradigm has been criticized, yet most data suggest that Aβ plays a key role in the disease. Here, a new loss-of-function hypothesis is synthesized that accounts...

  11. 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)

  12. Cavity solitons in a microring dimer with gain and loss

    Science.gov (United States)

    Milián, Carles; Kartashov, Yaroslav V.; Skryabin, Dmitry V.; Torner, Lluis

    2018-03-01

    We address a pair of vertically coupled microring resonators with gain and loss pumped by a single-frequency field. Coupling between microrings results in a twofold splitting of the single microring resonance that increases when gain and losses decrease and that gives rise to two different cavity soliton (CS) families. We show that the existence regions of CSs are tunable and that both CS families can be stable in the presence of an imbalance between gain and losses in the two microrings. These findings enable experimental realization of frequency combs in configurations with active microrings and contribute towards the realization of compact multisoliton comb sources.

  13. Antithrombotic therapy for pregnancy loss.

    Science.gov (United States)

    de Jong, Paulien G; Goddijn, Mariëtte; Middeldorp, Saskia

    2013-01-01

    BACKGROUND Although an association between thrombophilia and pregnancy loss has been observed in many studies, little is known about the pathophysiological mechanisms behind this association. Considering the association between thrombophilia and pregnancy loss, the efficacy of antithrombotic therapy for women with pregnancy loss (with or without thrombophilia) has been studied for the past 30 years. METHODS We performed a comprehensive review of the literature on the strength of the association between thrombophilia and pregnancy loss, the pathophysiological mechanisms and the efficacy of antithrombotic therapy to increase the chance of live birth. RESULTS The association between pregnancy loss and thrombophilia varies according to the type of thrombophilia (e.g. antiphospholipid syndrome versus forms of inherited thrombophilia) and according to the type of pregnancy loss (single versus recurrent pregnancy loss and early versus late pregnancy loss). Thrombophilia may induce thrombosis in decidual vessels or impair placentation through hypercoagulability and inflammation, but these hypotheses need further verification. For women with antiphospholipid syndrome, evidence from small-sized trials suggests a beneficial effect of antithrombotic therapy but additional randomized controlled trials are essential to confirm this. Whether antithrombotic therapy increases the chance of live birth in women with inherited thrombophilia is unknown. Recent randomized controlled trials have consistently shown that antithrombotic therapy does not increase the chance of live birth in women with unexplained recurrent miscarriage. CONCLUSIONS There are large gaps in knowledge and a lack of evidence for treatment of women with pregnancy loss with thrombophilia. To provide a solid base for clinical practice, further studies on the role of coagulation in reproduction, as well as international collaborations in randomized controlled trials of antithrombotic therapy in women with pregnancy

  14. Magnetic Field

    DEFF Research Database (Denmark)

    Olsen, Nils

    2015-01-01

    of the fluid flow at the top of the core. However, what is measured at or near the surface of the Earth is the superposition of the core field and fields caused by magnetized rocks in the Earth’s crust, by electric currents flowing in the ionosphere, magnetosphere, and oceans, and by currents induced......he Earth has a large and complicated magnetic field, the major part of which is produced by a self-sustaining dynamo operating in the fluid outer core. Magnetic field observations provide one of the few tools for remote sensing the Earth’s deep interior, especially regarding the dynamics...... in the Earth by time-varying external fields. These sources have their specific characteristics in terms of spatial and temporal variations, and their proper separation, based on magnetic measurements, is a major challenge. Such a separation is a prerequisite for remote sensing by means of magnetic field...

  15. Trends in global earthquake loss

    Science.gov (United States)

    Arnst, Isabel; Wenzel, Friedemann; Daniell, James

    2016-04-01

    Based on the CATDAT damage and loss database we analyse global trends of earthquake losses (in current values) and fatalities for the period between 1900 and 2015 from a statistical perspective. For this time period the data are complete for magnitudes above 6. First, we study the basic statistics of losses and find that losses below 10 bl. US satisfy approximately a power law with an exponent of 1.7 for the cumulative distribution. Higher loss values are modelled with the General Pareto Distribution (GPD). The 'transition' between power law and GPD is determined with the Mean Excess Function. We split the data set into a period of pre 1955 and post 1955 loss data as in those periods the exposure is significantly different due to population growth. The Annual Average Loss (AAL) for direct damage for events below 10 bl. US differs by a factor of 6, whereas the incorporation of the extreme loss events increases the AAL from 25 bl. US/yr to 30 bl. US/yr. Annual Average Deaths (AAD) show little (30%) difference for events below 6.000 fatalities and AAD values of 19.000 and 26.000 deaths per year if extreme values are incorporated. With data on the global Gross Domestic Product (GDP) that reflects the annual expenditures (consumption, investment, government spending) and on capital stock we relate losses to the economic capacity of societies and find that GDP (in real terms) grows much faster than losses so that the latter one play a decreasing role given the growing prosperity of mankind. This reasoning does not necessarily apply on a regional scale. Main conclusions of the analysis are that (a) a correct projection of historic loss values to nowadays US values is critical; (b) extreme value analysis is mandatory; (c) growing exposure is reflected in the AAL and AAD results for the periods pre and post 1955 events; (d) scaling loss values with global GDP data indicates that the relative size - from a global perspective - of losses decreases rapidly over time.

  16. 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.

  17. Pediatric Sudden Sensorineural Hearing Loss.

    Science.gov (United States)

    Kizilay, Ahmet; Koca, Çiğdem Firat

    2016-06-01

    Sudden sensorineural hearing loss is defined as sudden unilateral or bilateral sensorineural hearing loss with at least 30 dB decrease in threshold in 3 contiguous test frequencies occurring over 72 hours or less. It is rare among children. The mechanism of the process and prognosis of the disorder remains unclear. The current incidence of sudden sensorineural hearing loss among pediatric population is unknown. The authors carried out a retrospective chart analysis of patients under 15 years of age from 2004 to 2015, who consulted to the Otolaryngology Head and Neck Surgery Department of Inonu University Medical Faculty. Age, sex, number of affected ear and side, audiometric evaluations, medical follow-up, treatment method, duration of treatment recovery, associated complaints; tinnitus and/or vertigo, presence of mumps disease were recorded for each patient. A 4-frequency pure-tone average (500, 1000, 2000, and 4000 Hz) was calculated for each ear. Complete recovery, defined as some hearing level compared with the nonaffected ear, was observed in 3 patients (21.4 %) and there was no partial hearing recovery. The hearing loss of 11 patient remained unchanged after prednisolone treatment. Two of the 11 patients had bilaterally total sensorineural hearing loss and evaluated as appropriate for cochlear implantation. Sex of patient and laterality of hearing loss were not correlated with hearing recovery. Sensorineural hearing loss among pediatrics has been the issue of otolaryngologists. The incidence, etiology, and treatment methods should be more studied.

  18. Interface losses in multimaterial resonators

    DEFF Research Database (Denmark)

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

    2014-01-01

    vibrational modes to achieve a total of more than 3000 experimental points that allow us to quantify the contribution of surface and volume intrinsic (material related) losses in MEMS resonators. We conclude that the losses in the interface between silicon nitride and aluminum is a very important contributor......We present an extensive study shedding light on the role of surface and bulk losses in micromechanical resonators. We fabricate thin silicon nitride membranes of different sizes and we coat them with different thicknesses of metal. We later characterize the 81 lowest out-of-plane flexural...

  19. [Reversible damages: loss of chance].

    Science.gov (United States)

    Béry, Alain

    2013-03-01

    Chance is the probability that a particular event may or may not occur and, in this sense, a loss of chance∗∗ can be defined as the missed opportunities resulting from the loss of the possibility that a favorable event will occur (a contrario, the failure to take risks)∗∗∗. This is a self-imposed liability that should be distinguished from the final damage. Moral damage is a notion that is very close to loss of chance although it is based on indemnification from the final damage of an affliction or malady. © EDP Sciences, SFODF, 2013.

  20. 26 CFR 1.904(f)-1 - Overall foreign loss and the overall foreign loss account.

    Science.gov (United States)

    2010-04-01

    ... overall foreign losses: A foreign oil related loss under the FORI limitation and an overall foreign loss... amount of any— (A) Expropriation losses for such year (as defined in section 172(h)), or (B) Losses for...

  1. Nutrient enrichment, biodiversity loss, and consequent declines in ecosystem productivity.

    Science.gov (United States)

    Isbell, Forest; Reich, Peter B; Tilman, David; Hobbie, Sarah E; Polasky, Stephen; Binder, Seth

    2013-07-16

    Anthropogenic drivers of environmental change often have multiple effects, including changes in biodiversity, species composition, and ecosystem functioning. It remains unknown whether such shifts in biodiversity and species composition may, themselves, be major contributors to the total, long-term impacts of anthropogenic drivers on ecosystem functioning. Moreover, although numerous experiments have shown that random losses of species impact the functioning of ecosystems, human-caused losses of biodiversity are rarely random. Here we use results from long-term grassland field experiments to test for direct effects of chronic nutrient enrichment on ecosystem productivity, and for indirect effects of enrichment on productivity mediated by resultant species losses. We found that ecosystem productivity decreased through time most in plots that lost the most species. Chronic nitrogen addition also led to the nonrandom loss of initially dominant native perennial C4 grasses. This loss of dominant plant species was associated with twice as great a loss of productivity per lost species than occurred with random species loss in a nearby biodiversity experiment. Thus, although chronic nitrogen enrichment initially increased productivity, it also led to loss of plant species, including initially dominant species, which then caused substantial diminishing returns from nitrogen fertilization. In contrast, elevated CO2 did not decrease grassland plant diversity, and it consistently promoted productivity over time. Our results support the hypothesis that the long-term impacts of anthropogenic drivers of environmental change on ecosystem functioning can strongly depend on how such drivers gradually decrease biodiversity and restructure communities.

  2. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Programs Recommendations & Guidelines Free Materials Parent’s Guide Multimedia & Tools My ... Hearing plays an essential role in communication, speech and language development, and learning. Even a small amount of hearing loss can ...

  3. Hires and Losses Tracking System

    Data.gov (United States)

    Social Security Administration — This database contains data about the hires and losses of employees for the Office of Systems-those who join or leave the Office of Systems and those who transfer...

  4. Age-Related Hearing Loss

    Science.gov (United States)

    ... hearing loss. Here are the most common ones: Styles of hearing aids Source: NIH/NIDCD Hearing aids ... information, contact us at: NIDCD Information Clearinghouse 1 Communication Avenue Bethesda, MD 20892-3456 Toll-free voice: ( ...

  5. Age-related hearing loss

    Science.gov (United States)

    ... genes and loud noise (from rock concerts or music headphones) may play a large role. The following ... hearing loss) Speech reading (lip reading and using visual cues to aid communication) A cochlear implant may ...

  6. Abandoning weight-loss programmes

    African Journals Online (AJOL)

    /social ... quotes published repons to substantiate this. Indeed, in a ... FROM A WEIGHT-LOSS PROGRAMME. Variable. No. %. " Response. Sex. Rank. Male. 6. 12. Issues. No. %" order. Female. 44. 88. Motivational. Age (yrs). Doubt own ability ...

  7. Occupational hearing loss in farmers.

    OpenAIRE

    Plakke, B L; Dare, E

    1992-01-01

    Studies have shown that there is a great deal of high-frequency sensorineural hearing loss among farmers. The studies have failed, however, to differentiate farmers who have occupational noise exposure only from other potential hearing loss etiologies. This study, through extensive case history information, has isolated a farm noise-exposure group and matched its members by age with persons with no significant noise exposure. Results indicate that farmers exposed only to noise from farming ha...

  8. Job loss and broken partnerships

    DEFF Research Database (Denmark)

    Kriegbaum, Margit; Christensen, Ulla; Lund, Rikke

    2008-01-01

    The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD).......The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD)....

  9. Loss Aversion in the Laboratory

    OpenAIRE

    Morrison, William G.; Oxoby, Robert J.

    2014-01-01

    We report the results of a laboratory experiment testing for the existence of loss aversion in a standard risk aversion protocol (Holt and Laury, 2002). In our experiment, participants earn and retain money for a week before using it in an incentivized risk preference elicitation task. We find loss aversion, distinct from risk aversion, has a significant effect on behavior resulting in participants requiring higher compensation to bear risk.

  10. Definition of fluctuant hearing loss.

    Science.gov (United States)

    Shea, J J

    1975-06-01

    In summary, fluctuant hearing loss is defined as a disorder of the inner ear characterized by fullness, roaring tinnitus, and fluctuations in hearing. It is believed to be caused by an inadequate absorption of endolymph from the endolymphatic sac, with or without one or more metabolic disorders, that interferes with the delicate balance between the production and absorption of endolymph and thus produces cochlear hydrops. This triad of fullness, roaring tinnitus, and fluctuant hearing loss resulting from cochlear hydrops is much more common than the quadrad of true turning vertigo, fullness, roaring tinnitus, and fluctuant hearing loss due to vestibular and cochlear hydrops known as Meniere's disease. Although patients with fluctuant hearing loss only may eventually develop vertigo as the chief complaint and then be said to have Meniere's disease, it is remarkable how many patients continue to suffer mainly from cochlear symptoms at all times. It would appear, because of the greater frequency of fluctuant hearing loss than in Meniere's disease, that the cochlear labyrinth is more susceptible to hydrops than the vestibular labyrinth. For the purposes of diagnosis and treatment it is very useful to separate patients into those with fluctuant hearing loss and those with Meniere's disease.

  11. Magnetic fields

    International Nuclear Information System (INIS)

    Mestel, L.; Arizona Univ., Tucson)

    1985-01-01

    The role of the Galactic magnetic field in the early stages of star formation is examined. The dynamical and observational consequences of the anisotropic collapse of cool gas clouds permeated by the local Galactic magnetic field are discussed. Magneto-gravitational equilibria of such clouds with subcritical mass-flux ratios, especially in the thin disk approximation, are addressed. Magnetic braking of both subcritical and supercritical masses is considered, and the consequences of flux leakage during the molecular cloud phase are discussed, including the effect on field topology

  12. Field arithmetic

    CERN Document Server

    Fried, Michael D

    2006-01-01

    Field Arithmetic explores Diophantine fields through their absolute Galois groups. This largely self-contained treatment starts with techniques from algebraic geometry, number theory, and profinite groups. Graduate students can effectively learn generalizations of finite field ideas. We use Haar measure on the absolute Galois group to replace counting arguments. New Chebotarev density variants interpret diophantine properties. Here we have the only complete treatment of Galois stratifications, used by Denef and Loeser, et al, to study Chow motives of Diophantine statements.Progress from the fi

  13. AC loss characteristics of Bi-2223 HTS tapes under bending

    International Nuclear Information System (INIS)

    Kim, Hae-Joon; Kim, J.H.; Cho, J.W.; Sim, K.D.; Kim, S.; Oh, S.S.; Kwag, D.S.; Kim, H.J.; Bae, J.H.; Seong, K.C.

    2006-01-01

    Superconductor is developed for applications in high-power devices such as power-transmission cables, transformers, motors and generators. In such applications, HTS tapes are subjected to various kinds of stress or strain. AC loss is also important consideration for many large-scale superconducting devices. In the fabrication of the devices, the critical current (I c ) of the high temperature superconductor degrades due to many reasons including the tension applied by bending and thermal contraction. These mechanical loads reduce the I c of superconducting wire and the I c degradation affects the AC loss of the wire. The I c degradation and AC loss of Bi-2223 HTS tape were measured under tension and bending conditions at 77 K and self-field. Moreover, the frequency characteristics of AC loss was measured at the 30-480 Hz. As a result, self-field penetrates the deeper into the conductor at the lower frequency, which means higher self-field losses per cycle

  14. Fast particle loss channels in Wendelstein 7-X

    Science.gov (United States)

    Faustin, J. M.; Cooper, W. A.; Graves, J. P.; Pfefferlé, D.; Geiger, J.

    2016-09-01

    One of the main goals of Wendelstein 7-X (W7-X) is to demonstrate the fast particle confinement properties of the quasi-isodynamic stellarator concept. Fast particle populations will be produced either by Neutral Beam Injection (NBI) or by minority Ion Cyclotron Resonant Heating (ICRH). A fraction of these particles are expected to be lost (even without collisions), despite the optimisation procedure used for the W7-X design. Confinement properties of NBI particles in W7-X were presented in the paper of Drevlak et al (2014 Nucl. Fusion 54 073002). A detailed study is presented here where the loss patterns of an NBI population are described. In particular, focussing on a high-mirror equilibrium, the confinement of fast ions with varying energy injection is studied under collisional conditions. It is found that collisions are not only responsible for classical transport losses but also enhance drift induced losses caused by trapped particles. Moreover, an asymmetry is found in the toroidal position of particle losses which can be explained by local variation in the equilibrium field. The effects of a neoclassically resolved radial electric field are also investigated. Fast particle confinement is significantly improved by the associated \\boldsymbol{E}× \\boldsymbol{B} drift. In particular, an increasing radial electric field helps to reduce and even stop the losses due to the 3D equilibrium structure for times comparable to slowing down time.

  15. Field Notes

    Data.gov (United States)

    US Agency for International Development — This is a mobile application for capturing images , data, and geolocation for USAID projects in the field. The data is then stored on a server in AllNet. The...

  16. Self-Reported Losses Versus Actual Losses in Online Gambling: An Empirical Study.

    Science.gov (United States)

    Auer, Michael; Griffiths, Mark D

    2017-09-01

    Many research findings in the gambling studies field rely on self-report data. A very small body of empirical research also suggests that when using self-report, players report their gambling losses inaccurately. The aim of the present study was to evaluate the differences between objective and subjective gambling spent data by comparing gambler's actual behavioral tracking data with their self-report data over a 1-month period. A total of 17,742 Norwegian online gamblers were asked to participate in an online survey. Of those surveyed, 1335 gamblers answered questions relating to gambling expenditure that could be compared with their actual gambling behavior. The study found that the estimated loss self-reported by gamblers was correlated with the actual objective loss and that players with higher losses tended to have more difficulty estimating their gambling expenditure (i.e., players who spent more money gambling also appeared to have more trouble estimating their expenses accurately). Overall, the findings demonstrate that caution is warranted when using self-report data relating to amount of money spent gambling in any studies that are totally reliant on self-report data.

  17. 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 self-reported function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R 2 = 0.56, p 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.

  18. Magnetic fields at Neptune

    International Nuclear Information System (INIS)

    Ness, N.F.; Acuna, M.H.; Burlaga, L.F.; Connerney, J.E.P.; Lepping, R.P.; Neubauer, F.M.

    1989-01-01

    The National Aeronautics and Space Administration Goddard Space Flight Center-University of Delaware Bartol Research Institute magnetic field experiment on the Voyager 2 spacecraft discovered a strong and complex intrinsic magnetic field of Neptune and an associated magnetosphere and magnetic tail. A maximum magnetic field of nearly 10,000 nanoteslas (1 nanotesla = 10 -5 gauss) was observed near closest approach, at a distance of 1.18 R N . The planetary magnetic field between 4 and 15 R N can be well represented by an offset tilted magnetic dipole (OTD), displaced from the center of Neptune by the surprisingly large amount of 0.55 R N and inclined by 47 degrees with respect to the rotation axis. Within 4 R N , the magnetic field representation must include localized sources or higher order magnetic multipoles, or both, which are not yet well determined. As the spacecraft exited the magnetosphere, the magnetic tail appeared to be monopolar, and no crossings of an imbedded magnetic field reversal or plasma neutral sheet were observed. The auroral zones are most likely located far from the rotation poles and may have a complicated geometry. The rings and all the known moons of Neptune are imbedded deep inside the magnetosphere, except for Nereid, which is outside when sunward of the planet. The radiation belts will have a complex structure owing to the absorption of energetic particles by the moons and rings of Neptune and losses associated with the significant changes in the diurnally varying magnetosphere configuration. In an astrophysical context, the magnetic field of Neptune, like that of Uranus, may be described as that of an oblique rotator

  19. Recurrent pregnancy loss: current perspectives

    Directory of Open Access Journals (Sweden)

    El Hachem H

    2017-05-01

    Full Text Available Hady El Hachem,1,2 Vincent Crepaux,3 Pascale May-Panloup,4 Philippe Descamps,3 Guillaume Legendre,3 Pierre-Emmanuel Bouet3 1Department of Reproductive Medicine, Ovo Clinic, Montréal, QC, Canada; 2Department of Obstetrics and Gynecology, University of Montreal, Montréal, QC, Canada; 3Department of Obstetrics and Gynecology, Angers University Hopsital, Angers, France; 4Department of Reproductive Biology, Angers University Hospital, Angers, France Abstract: Recurrent pregnancy loss is an important reproductive health issue, affecting 2%–5% of couples. Common established causes include uterine anomalies, antiphospholipid syndrome, hormonal and metabolic disorders, and cytogenetic abnormalities. Other etiologies have been proposed but are still considered controversial, such as chronic endometritis, inherited thrombophilias, luteal phase deficiency, and high sperm DNA fragmentation levels. Over the years, evidence-based treatments such as surgical correction of uterine anomalies or aspirin and heparin for antiphospholipid syndrome have improved the outcomes for couples with recurrent pregnancy loss. However, almost half of the cases remain unexplained and are empirically treated using progesterone supplementation, anticoagulation, and/or immunomodulatory treatments. Regardless of the cause, the long-term prognosis of couples with recurrent pregnancy loss is good, and most eventually achieve a healthy live birth. However, multiple pregnancy losses can have a significant psychological toll on affected couples, and many efforts are being made to improve treatments and decrease the time needed to achieve a successful pregnancy. This article reviews the established and controversial etiologies, and the recommended therapeutic strategies, with a special focus on unexplained recurrent pregnancy losses and the empiric treatments used nowadays. It also discusses the current role of preimplantation genetic testing in the management of recurrent pregnancy

  20. Asymmetric many-body loss in a bosonic double well

    Science.gov (United States)

    Denis, Zakari; Tiene, Antonio; Salasnich, Luca; Wimberger, Sandro

    2018-01-01

    A Bose gas in a double well is investigated in the presence of single-particle, two-body, and three-body asymmetric loss. The loss induces an interesting decay behavior of the total population as well as a possibility to control the dynamics of the system. In the noninteracting limit with asymmetric single-body dissipation, the dynamics of the populations can be obtained analytically. The general many-body problem requires, however, an adequate approximation. We use a mean-field approximation and the Bogoliubov back reaction beyond mean-field truncation, which we extend up to three-body loss. Both methods are compared with exact many-body Monte Carlo simulations.

  1. Chromosome missegregation causes colon cancer by APC loss of heterozygosity.

    NARCIS (Netherlands)

    Baker, D.J.; Deursen, J.M.A. van

    2010-01-01

    A longstanding hypothesis in the field of cancer biology is that aneuploidy causes cancer by promoting loss of chromosomes that contain tumor suppressor genes. By crossing aneuploidyprone Bub1 hypomorphic mice onto a heterozygous null background for p53, we provided conclusive evidence for this

  2. Loss of sunflower seeds to columbids in South Africa: economic ...

    African Journals Online (AJOL)

    A survey across the sunflower production region of South Africa during November 2003 to July 2005 estimated the loss of sunflower seeds to columbids (doves and pigeons, Aves: Columbidae). Farmers estimated that 12.7% of the national yield was lost to columbids. In a follow-up survey, 37 sunflower fields were visited ...

  3. Loss Prediction of Low Re Flow Through Quasiperiodic Serpentine Channels

    Science.gov (United States)

    Becker, Sid

    2017-11-01

    Low Re internal flow through a complex structure whose geometry is regular (periodically uniform) will experience losses that are periodically regular and may be predicted using simple correlations. In many porous media applications this is represented by Darcy's Law. This study considers the prediction of losses through a channel whose geometry is periodic but with characteristic length scales that vary in the direction of bulk flow. Asymptotic expansions of the variation in the characteristic length are implemented in flow simulations in order to determine a correlation relating local hydraulic permeability to local channel geometry. In this way the local losses may be predicted without requiring the explicit solution of the flow field for every specific channel geometry. Several test cases are presented showing that using these correlations, the local pressure losses may predicted to within 0.5% agreement with the solution to the Navier-Stokes Equations.

  4. Water Loss in Small Settlements

    Directory of Open Access Journals (Sweden)

    Mindaugas Rimeika

    2014-10-01

    Full Text Available The main performance indicators of a water supply system include the quality and safety of water, continuous work, relevant pressure and small water loss. The majority of foreign and local projects on reducing water loss have been carried out in the water supply systems of metropolitans; however, the specificity of small settlements differs from that of big cities. Differences can be observed not only in the development of infrastructure and technical indicators but also in the features of water consumption. The article presents the analysis of water loss formation and describes reduction measures in a small settlement. The conducted research defines that water loss in big cities is much smaller than that in small settlements. The major part of water used in small settlements is applied for agrarian purposes rather than for domestic needs. It has been found that water is employed for the irrigation of plants and livestock watering, which often is not accounted. Research also shows that slight (<0.2 m³/h physical water loss (holes in the network that occur in small settlements may compose up to 30% of all water supplied to the water network.

  5. Occupational hearing loss in Korea.

    Science.gov (United States)

    Kim, Kyoo Sang

    2010-12-01

    In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases exceeding exposure limit among workplace hazards. NIHL is the most common occupational disease except work-related disease such as musculoskeletal disorders and cerebrovascular diseases, and NIHL prevalence is thought to be much higher than reported in official publications. Noise affecting hearing comes from various sources such as workplaces, military settings, areas with exposure to high noise, and specific noise sources. There is also occupational hearing loss by non-noise including chemicals such as organic solvents and heavy metals, barotrauma, and trauma due to welding spark. Noise affects daily life through audiological effects such as hearing loss and tinnitus, non-audiological physical effects (e.g., cardiovascular), and psychosocial and behavioral effects. Development of systematic and comprehensive hearing conservation programs for lowering the noise level in workplaces and preventing the NIHL, and preparation of technological, administrative system for its settlement at workplace are urgently needed.

  6. [Presbycusis - Age Related Hearing Loss].

    Science.gov (United States)

    Fischer, N; Weber, B; Riechelmann, H

    2016-07-01

    Presbycusis or age related hearing loss can be defined as a progressive, bilateral and symmetrical sensorineural hearing loss due to age related degeneration of inner ear structures. It can be considered a multifactorial complex disorder with environmental and genetic factors. The molecular, electrophysiological and histological damage at different levels of the inner ear cause a progressive hearing loss, which usually affects the high frequencies of hearing. The resulting poor speech recognition has a negative impact on cognitive, emotional and social function in older adults. Recent investigations revealed an association between hearing impairment and social isolation, anxiety, depression and cognitive decline in elderly. These findings emphasize the importance of diagnosis and treating hearing loss in the elderly population. Hearing aids are the most commonly used devices for treating presbycusis. The technical progress of implantable hearing devices allows an effective hearing rehabilitation even in elderly with severe hearing loss. However, most people with hearing impairments are not treated adequately. © Georg Thieme Verlag KG Stuttgart · New York.

  7. 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

  8. Field theories with subcanonical fields

    International Nuclear Information System (INIS)

    Bigi, I.I.Y.

    1976-01-01

    The properties of quantum field theories with spinor fields of dimension less than the canonical value of 3/2 are studied. As a starting point for the application of common perturbation theory we look for the linear version of these theories. A gange-interaction is introduced and with the aid of power counting the renormalizability of the theory is shown. It follows that in the case of a spinor-field with negative dimension renormalization can only be attained if the interaction has a further symmetry. By this symmetry the theory is determined in an unequivocal way. The gange-interaction introduced in the theory leads to a spontaneous breakdown of scale invariance whereby masses are produced. At the same time the spinor-field operators can now be separated in two orthogonal sections with opposite norm. It is proposed to use the section with negative (positive) norm to describe hadrons (leptons) respectively. (orig./WL) [de

  9. Weight loss history as a predictor of weight loss: results from Phase I of the weight loss maintenance trial

    OpenAIRE

    Myers, Valerie H.; McVay, Megan A.; Champagne, Catherine M.; Hollis, Jack F.; Coughlin, Janelle W.; Funk, Kristine L.; Gullion, Christina M.; Jerome, Gerald J.; Loria, Catherine M.; Samuel-Hodge, Carmen D.; Stevens, Victor J.; Svetkey, Laura P.; Brantley, Phillip J.

    2012-01-01

    Past studies have suggested that weight loss history is associated with subsequent weight loss. However, questions remain whether method and amount of weight lost in previous attempts impacts current weight loss efforts. This study utilized data from the Weight Loss Maintenance Trial to examine the association between weight loss history and weight loss outcomes in a diverse sample of high-risk individuals. Multivariate regression analysis was conducted to determine which specific aspects of ...

  10. Predicting Suitable field workdays for soil tillage in North Central ...

    African Journals Online (AJOL)

    Oladimeji S. Ife

    machinery, soil etc.) If a crop is planted at a time other than within the optimum period, reduced yield can occur leading to losses. When the crop matures, and is not harvested within the optimum period, some of it may deteriorate in the field, leading to losses. These losses attract extra costs usually referred to as timeliness ...

  11. Economic inequality predicts biodiversity loss.

    Directory of Open Access Journals (Sweden)

    Gregory M Mikkelson

    Full Text Available Human activity is causing high rates of biodiversity loss. Yet, surprisingly little is known about the extent to which socioeconomic factors exacerbate or ameliorate our impacts on biological diversity. One such factor, economic inequality, has been shown to affect public health, and has been linked to environmental problems in general. We tested how strongly economic inequality is related to biodiversity loss in particular. We found that among countries, and among US states, the number of species that are threatened or declining increases substantially with the Gini ratio of income inequality. At both levels of analysis, the connection between income inequality and biodiversity loss persists after controlling for biophysical conditions, human population size, and per capita GDP or income. Future research should explore potential mechanisms behind this equality-biodiversity relationship. Our results suggest that economic reforms would go hand in hand with, if not serving as a prerequisite for, effective conservation.

  12. Endocrinology of recurrent pregnancy loss.

    Science.gov (United States)

    Arredondo, Francisco; Noble, Luis S

    2006-02-01

    Following implantation, the maintenance of the pregnancy is dependent on a multitude of endocrinological events that will eventually aid in the successful growth and development of the fetus. Although the great majority of pregnant women have no pre-existing endocrine abnormalities, a small number of women can have certain endocrine alterations that could potentially lead to recurrent pregnancy losses. It is estimated that approximately 8 to 12% of all pregnancy losses are the result of endocrine factors. During the preimplantation period, the uterus undergoes important developmental changes stimulated by estrogen, and more importantly, progesterone. Progesterone is essential for the successful implantation and maintenance of pregnancy. Therefore, disorders related to inadequate progesterone secretion by the corpus luteum are likely to affect the outcome of the pregnancy. Luteal phase deficiency, hyperprolactinemia, and polycystic ovarian syndrome are some examples. Several other endocrinological abnormalities such as thyroid disease, hypoparathyroidism, uncontrolled diabetes, and decreased ovarian reserve have been implicated as etiologic factors for recurrent pregnancy loss.

  13. FTO genotype and weight loss

    DEFF Research Database (Denmark)

    Livingstone, Katherine M; Celis-Morales, Carlos; Papandonatos, George D

    2016-01-01

    OBJECTIVE: To assess the effect of the FTO genotype on weight loss after dietary, physical activity, or drug based interventions in randomised controlled trials. DESIGN: Systematic review and random effects meta-analysis of individual participant data from randomised controlled trials. DATA SOURCES...... circumference in response to weight loss intervention were not significantly different between FTO genotypes. Sensitivity analyses indicated that differential changes in body mass index, body weight, and waist circumference by FTO genotype did not differ by intervention type, intervention length, ethnicity......, sample size, sex, and baseline body mass index and age category. CONCLUSIONS: We have observed that carriage of the FTO minor allele was not associated with differential change in adiposity after weight loss interventions. These findings show that individuals carrying the minor allele respond equally...

  14. Hearing loss at work? Hearing loss from leisure activities?

    CERN Multimedia

    2006-01-01

    The nurses of the Medical Service would like invite all persons working on the CERN site to take part in a: HEARING LOSS DETECTION WEEK From 28 August to 1st September 2006 At the Infirmary, Building 57 from 9 a.m. to 4 p.m. Hearing tests - advice - information - documentation - protective equipment

  15. Management of hair loss diseases

    Directory of Open Access Journals (Sweden)

    Manabu Ohyama

    2010-12-01

    Full Text Available The treatment of hair loss diseases is sometimes difficult because of insufficient efficacy and limited options. However, recent advances in understanding of the pathophysiology and development of new remedies have improved the treatment of refractory hair loss conditions. In this article, an update on the management of hair loss diseases is provided, especially focusing on recently reported therapeutic approaches for alopecia areata (AA. An accurate diagnosis is indispensable to optimize treatment. Dry dermoscopy represents new diagnostic techniques, which could enable the differentiation of barely indistinguishable alopecias, e.g. AA and trichotillomania. An organized scalp biopsy adopting both vertical and transverse sectioning approaches also provides a deep insight into the pathophysiology of ongoing alopecias. Among various treatments for AA, intraregional corticosteroid and contact immunotherapy have been recognized as first-line therapies. However, some AA cases are refractory to both treatments. Recent studies have demonstrated the efficacy of pulse corticosteroid therapy or the combination of oral psoralen ultraviolet A therapy and systemic corticosteroids for severe AA. Previous clinical observations have suggested the potential role of antihistamines as supportive medications for AA. Experimental evaluation using AA model mice further supports their effectiveness in AA treatment. Finasteride opens up new possibilities for the treatment of androgenetic alopecia. For androgenetic alopecia patients refractory to finasteride, the combination of finasteride with topical minoxidil or the administration of dutasteride, another 5 alpha-reductase inhibitor, may provide better outcomes. Scarring alopecia is the most difficult form of hair loss disorder to treat. The bulge stem cell area is destroyed by unnecessary immune reactions with resultant permanent loss of hair follicle structures in scarring alopecia. Currently, treatment options for

  16. Iodine losses during Winkler titrations

    Science.gov (United States)

    Knapp, George P.; Stalcup, Marvel C.; Stanley, Robert J.

    1991-01-01

    An experiment designed to measure iodine loss during the aliquot version of the Winkler titration for dissolved oxygen in seawater shows that 0.01-0.03 ml l -1 equivalent oxygen is lost at typical oceanic concentrations in the method presently used. A standardization technique, which mimics that employed during the titration of seawater samples, compensates for this iodine loss throughout the oceanic range. This result, contradicting an earlier report by GREEN and CARRITT (1966, Analyst, 91, 207-208), demonstrates that the whole-bottle method of oxygen titration is not to be preferred over the aliquot method.

  17. Weight Loss Surgery: An Option for Teens?

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Weight Loss Surgery: An Option for Teens? Page Content Article ... operation should not be made hastily. Candidates for Weight Loss Surgery Weight loss surgery is advisable only for ...

  18. Exercise and activity for weight loss

    Science.gov (United States)

    Weight loss - activity; Weight loss - exercise; Obesity - activity ... Calories used in exercise > calories eaten = weight loss. This means that to lose weight, the number of calories you burn by exercising needs to be greater than the number of ...

  19. gauge fields

    Indian Academy of Sciences (India)

    Abstract. Painlevé test (Jimbo et al [1]) for integrability for the Yang's self-dual equa- tions for SU(2) gauge fields has been revisited. Jimbo et al analysed the complex form of the equations with a rather restricted form of singularity manifold. They did not discuss exact solutions in that context. Here the analysis has been done ...

  20. Fields Medallists

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 11. Fields Medallists - Curtis T. McMullen. Nimish A Shah. Research News Volume 4 Issue 11 November 1999 pp 80-83. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/11/0080-0083 ...