historical variation
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2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ravi Kumar Guntu ◽  
Ankit Agarwal

AbstractCompound extremes exhibit greater adverse impacts than their univariate counterparts. Studies have reported changes in frequency and the spatial extent of extremes in India; however, investigation of compound extremes is in the infancy state. This study investigates the historical variation of compound dry and hot extremes (CDHE) and compound wet and cold extremes (CWCE) during the Indian summer monsoon period from 1951 to 2019 using monthly data. Results are analyzed for 10 identified homogeneous regions for India. Our results unravelled that CDHE (CWCE) frequency has increased (decreased) by 1–3 events per decade for the recent period (1977–2019) relative to the base period (1951–1976). Overall, the increasing (decreasing) pattern of CDHE (CWCE) is high across North-central India, Western India, North-eastern India and South-eastern coastlines. Our findings help in identification of the parts of the country affected by frequent and widespread CDHE during the recent period, which is alarming. More detailed assessments are required to disentangle the complex physical process of compound extremes to improve risk management options.


2021 ◽  
Vol 118 (23) ◽  
pp. e2026752118
Author(s):  
Kevin R. McCarthy ◽  
Tarra A. Von Holle ◽  
Laura L. Sutherland ◽  
Thomas H. Oguin ◽  
Gregory D. Sempowski ◽  
...  

Immune memory of a first infection with influenza virus establishes a lasting imprint. Recall of that memory dominates the response to later infections or vaccinations by antigenically drifted strains. Early childhood immunization before infection may leave an imprint with different characteristics. We report here a comparison of imprinting by vaccination and infection in a small cohort of nonhuman primates (NHPs). We assayed serum antibody responses for binding with hemaglutinnins (HAs) both from the infecting or immunizing strain (H3 A/Aichi 02/1968) and from strains representing later H3 antigenic clusters (“forward breadth”) and examined the effects of defined HA mutations on serum titers. Initial exposure by infection elicited strong HA-binding and neutralizing serum antibody responses but with little forward breadth; initial vaccination with HA from the same strain elicited a weaker response with little neutralizing activity but considerable breadth of binding, not only for later H3 HAs but also for HA of the 2009 H1 new pandemic virus. Memory imprinted by infection, reflected in the response to two immunizing boosts, was largely restricted (as in humans) to the outward-facing HA surface, the principal region of historical variation. Memory imprinted by immunization showed exposure to more widely distributed epitopes, including sites that have not varied during evolution of the H3 HA but that yield nonneutralizing responses. The mode of initial exposure thus affects both the strength of the response and the breadth of the imprint; design of next-generation vaccines will need to take the differences into account.


2021 ◽  
Vol 17 (1(23)) ◽  
pp. 24-34
Author(s):  
Iryna Shevchenko

 This article explores the role of metaphor in the conceptualization of economic crisis in English in terms of the sociohistorical – cognitive – linguistic interface. On the material of economic mass-media discourse of the 19th century “long depression”, the 20th century Great Depression and the 21st century Global Economic Crisis It reveals the concept historical variation and defines the vector of its development. It also develops the methodology of historical cognitive analysis and proves that being а part of human social-cultural practice cognition is of historical nature. I claim that in historical perspective conceptual metaphors vary in their source domains as the result of transformations of the concept structure. The vector of diachronic change of conceptual metaphors of economic crisis corresponds to cladogenesis, which is the process of evolutionary splitting based on branching.


PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252223
Author(s):  
Michelle N. Clements ◽  
Neal Russell ◽  
Julia A. Bielicki ◽  
Sally Ellis ◽  
Silke Gastine ◽  
...  

Background Paediatric global antibiotic guidelines are inconsistent, most likely due to the limited pharmacokinetic and efficacy data in this population. We investigated factors underlying variation in antibiotic dosing using data from five global point prevalence surveys. Methods & findings Data from 3,367 doses of the 16 most frequent intravenous antibiotics administered to children 1 month–12 years across 23 countries were analysed. For each antibiotic, we identified standard doses given as either weight-based doses (in mg/kg/day) or fixed daily doses (in mg/day), and investigated the pattern of dosing using each strategy. Factors underlying observed variation in weight-based doses were investigated using linear mixed effects models. Weight-based dosing (in mg/kg/day) clustered around a small number of peaks, and all antibiotics had 1–3 standard weight-based doses used in 5%-48% of doses. Dosing strategy was more often weight-based than fixed daily dosing for all antibiotics apart from teicoplanin, which had approximately equal proportions of dosing attributable to each strategy. No strong consistent patterns emerged to explain the historical variation in actual weight-based doses used apart from higher dosing seen in central nervous system infections, and lower in skin and soft tissue infections compared to lower respiratory tract infections. Higher dosing was noted in the Americas compared to the European region. Conclusions Antibiotic dosing in children clusters around a small number of doses, although variation remains. There is a clear opportunity for the clinical, scientific and public health communities to consolidate behind a consistent set of global antibiotic dosing guidelines to harmonise current practice and prioritise future research.


SOLA ◽  
2021 ◽  
Vol 17 (0) ◽  
pp. 184-190
Author(s):  
Syuichi Itahashi ◽  
Junichi Kurokawa ◽  
Toshimasa Ohara ◽  
Itsushi Uno ◽  
Shin-ichi Fujita

2020 ◽  
Author(s):  
Peter D. Fields ◽  
Gretchen Arnold ◽  
Joel M. Kniskern ◽  
Douglas R. Taylor

ABSTRACTThe phenotypic consequences of inbreeding typically result in a fitness decline proportional to the increase in the inbreeding coefficient, F. This basic assumption of a predictable, inverse relationship between fitness and F has been questioned by a number of empirical studies. We explored the relationship between population history and inbreeding in a metapopulation of the plant Silene latifolia, for which long-term data are available for the historical size and spatial distribution of hundreds of local demes. We used a population genetic analysis to estimate gene flow and bi-parental inbreeding (FIS) in demes with different histories of spatial isolation. A controlled crossing experiment examined whether the effect of inbreeding and outcrossing on fitness-related traits varied with different histories of population size and isolation. Historically isolated demes experienced less gene flow and an increase in FIS, as well as significant inbreeding advantage and outbreeding depression for traits expressed early in life. The causes of variation in the F-fitness relationship among populations will include variance in the distribution of deleterious recessive alleles driven by aspects of population history, including population size, founder effects, gene flow, bi-parental inbreeding, and opportunities for the purging of genetic load. Our findings show that isolation and historical variation in population size likely contribute substantial variation in past inbreeding and the consequences of future inbreeding across the metapopulation.


2020 ◽  
Vol 215 ◽  
pp. 108219 ◽  
Author(s):  
Esteban Calvo ◽  
José T. Medina ◽  
Katherine A. Ornstein ◽  
Ursula M. Staudinger ◽  
Linda P. Fried ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yacine Ben Chehida ◽  
Julie Thumloup ◽  
Cassie Schumacher ◽  
Timothy Harkins ◽  
Alex Aguilar ◽  
...  

Abstract Historical variation in food resources is expected to be a major driver of cetacean evolution, especially for the smallest species like porpoises. Despite major conservation issues among porpoise species (e.g., vaquita and finless), their evolutionary history remains understudied. Here, we reconstructed their evolutionary history across the speciation continuum. Phylogenetic analyses of 63 mitochondrial genomes suggest that porpoises radiated during the deep environmental changes of the Pliocene. However, all intra-specific subdivisions were shaped during the Quaternary glaciations. We observed analogous evolutionary patterns in both hemispheres associated with convergent evolution to coastal versus oceanic environments. This suggests that similar mechanisms are driving species diversification in northern (harbor and Dall’s) and southern species (spectacled and Burmeister’s). In contrast to previous studies, spectacled and Burmeister’s porpoises shared a more recent common ancestor than with the vaquita that diverged from southern species during the Pliocene. The low genetic diversity observed in the vaquita carried signatures of a very low population size since the last 5,000 years. Cryptic lineages within Dall’s, spectacled and Pacific harbor porpoises suggest a richer evolutionary history than previously suspected. These results provide a new perspective on the mechanisms driving diversification in porpoises and an evolutionary framework for their conservation.


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