40 research outputs found

    Climate biocapacity of Mongolia and its change

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    This paper has looked into the estimated results of climate biocapacity in Mongolia. The soil moisture supply was assessed through annual precipitation, Shashko’s humidity coefficient, Selyainov’s heat-moisture coefficient and Ivanov-Mezentsev climate biological productivity index. Finally, their long-term trends have been considered as well. The results are consistent with vegetation zones, summer mean pasture yield and existing arable farming region in the country. Therefore, the results are applicable in Mongolia’s conditions. Also, the heat supply during growing season is estimated by daily average temperature, which fluctuates from 5 and 10oC in spring and autumn respectively, the sum total of effective and active temperature. Since 1960, the growing season in the country has lengthened by 3 weeks and the sum of active temperature above 10oC has increased by 80-90oC, although the moisture supply of vegetation is weakening and moreover, climate biocapacity is decreasing

    Head Position in Stroke Trial (HeadPoST)- sitting-up vs lying-flat positioning of patients with acute stroke: study protocol for a cluster randomised controlled trial

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    Background Positioning a patient lying-flat in the acute phase of ischaemic stroke may improve recovery and reduce disability, but such a possibility has not been formally tested in a randomised trial. We therefore initiated the Head Position in Stroke Trial (HeadPoST) to determine the effects of lying-flat (0°) compared with sitting-up (≥30°) head positioning in the first 24 hours of hospital admission for patients with acute stroke. Methods/Design We plan to conduct an international, cluster randomised, crossover, open, blinded outcome-assessed clinical trial involving 140 study hospitals (clusters) with established acute stroke care programs. Each hospital will be randomly assigned to sequential policies of lying-flat (0°) or sitting-up (≥30°) head position as a ‘business as usual’ stroke care policy during the first 24 hours of admittance. Each hospital is required to recruit 60 consecutive patients with acute ischaemic stroke (AIS), and all patients with acute intracerebral haemorrhage (ICH) (an estimated average of 10), in the first randomised head position policy before crossing over to the second head position policy with a similar recruitment target. After collection of in-hospital clinical and management data and 7-day outcomes, central trained blinded assessors will conduct a telephone disability assessment with the modified Rankin Scale at 90 days. The primary outcome for analysis is a shift (defined as improvement) in death or disability on this scale. For a cluster size of 60 patients with AIS per intervention and with various assumptions including an intracluster correlation coefficient of 0.03, a sample size of 16,800 patients at 140 centres will provide 90 % power (α 0.05) to detect at least a 16 % relative improvement (shift) in an ordinal logistic regression analysis of the primary outcome. The treatment effect will also be assessed in all patients with ICH who are recruited during each treatment study period. Discussion HeadPoST is a large international clinical trial in which we will rigorously evaluate the effects of different head positioning in patients with acute stroke. Trial registration ClinicalTrials.gov identifier: NCT02162017 (date of registration: 27 April 2014); ANZCTR identifier: ACTRN12614000483651 (date of registration: 9 May 2014). Protocol version and date: version 2.2, 19 June 2014

    Flying Over an Infected Landscape: Distribution of Highly Pathogenic Avian Influenza H5N1 Risk in South Asia and Satellite Tracking of Wild Waterfowl

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    Highly pathogenic avian influenza (HPAI) H5N1 virus persists in Asia, posing a threat to poultry, wild birds, and humans. Previous work in Southeast Asia demonstrated that HPAI H5N1 risk is related to domestic ducks and people. Other studies discussed the role of migratory birds in the long distance spread of HPAI H5N1. However, the interplay between local persistence and long-distance dispersal has never been studied. We expand previous geospatial risk analysis to include South and Southeast Asia, and integrate the analysis with migration data of satellite-tracked wild waterfowl along the Central Asia flyway. We find that the population of domestic duck is the main factor delineating areas at risk of HPAI H5N1 spread in domestic poultry in South Asia, and that other risk factors, such as human population and chicken density, are associated with HPAI H5N1 risk within those areas. We also find that satellite tracked birds (Ruddy Shelduck and two Bar-headed Geese) reveal a direct spatio-temporal link between the HPAI H5N1 hot-spots identified in India and Bangladesh through our risk model, and the wild bird outbreaks in May–June–July 2009 in China (Qinghai Lake), Mongolia, and Russia. This suggests that the continental-scale dynamics of HPAI H5N1 are structured as a number of persistence areas delineated by domestic ducks, connected by rare transmission through migratory waterfowl

    Conjuntos excepcionais e alguns problemas de Mahler

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    Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Matemática, 2017.Seja f uma função inteira e transcendente. Denotamos por Sf o conjunto de todos os α ∈ ´Q tais que f(α) ∈ ´Q (o conjunto excepcional de f). Nessa dissertação, mostraremos quais subconjuntos de ´Q podem ser o conjunto excepcional de alguma função inteira e transcendente. Além disso, trataremos de dois problemas de Mahler relacionados a propriedades de funções inteiras e transcendentes. Mostraremos que existem funções inteiras e transcendentes que levam um subconjunto dos números de Liouville nele mesmo e daremos uma resposta positiva ao Problema B de Mahler: Problema B: Existe uma função inteira e transcendente f(z) = Σn =0 ∞ a nz n com coeficientes racionais tal que f( ´Q ) ⊆ ´Q e f−1( ´Q ) ⊆ ´Q ? .Let f be an entire transcendental function. We denote by Sf the set of all α ∈ ´Q such that f(α) ∈ ´Q (exceptional set of f). Throughout this dissertation, we will show which subsets of ´Q can be the exceptional set of some entire transcendental function. Moreover, we will deal with two of Mahler’s problems related to properties of entire transcendental functions. We will show that there are entire transcendental functions that map a subset of Liouville numbers in itself and we will give a positive answer for Mahler’s Problem B: Problem B: Is there an entire transcendental function f(z) = Σn =0 ∞ a nz n with rational coefficients such that que f( ´Q ) ⊆ ´Q e f−1( ´Q ) ⊆ ´Q ?

    The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations

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    The physiological and biomechanical requirements of flight at high altitude have been the subject of much interest. Here, we uncover a steep relation between heart rate and wingbeat frequency (raised to the exponent 3.5) and estimated metabolic power and wingbeat frequency (exponent 7) of migratory bar-headed geese. Flight costs increase more rapidly than anticipated as air density declines, which overturns prevailing expectations that this species should maintain high-altitude flight when traversing the Himalayas. Instead, a �roller coaster� strategy, of tracking the underlying terrain and discarding large altitude gains only to recoup them later in the flight with occasional benefits from orographic lift, is shown to be energetically advantageous for flights over the Himalayas
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