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1.
Eric D Roth 《Animal behaviour》2003,66(2):337-341
Studies have documented the presence of behavioural lateralization in many groups of lower vertebrates, demonstrating that these behaviours are not limited to mammals and birds. These studies suggest that the evolution of brain lateralization, often linked to lateralized behaviours, may have occurred early in evolutionary history and may not have been the result of multiple independent evolutionary events as previously thought. The goal of this study was to further document behavioural lateralization in another group of lower vertebrates, snakes. Given the importance of the coiling posture to snakes, I examined the coiling behaviour of a cottonmouth population. Coiling asymmetries were found at both the individual and population levels. However, the adaptive significance and mechanisms influencing this behaviour remain undefined. Additional research is needed to explore these areas and to link the lateralized behaviours documented in this and other studies directly to brain asymmetries before the evolutionary history of brain lateralization can be further resolved. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. 相似文献
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The pathogenic chytrid fungus, Batrachochytrium dendrobatidis, has been implicated as the main driver of many enigmatic amphibian declines in neotropical sites at high elevation. Batrachochytrium dendrobatidis is thought to be a waterborne pathogen limited by temperature, and the extent to which it persists and causes disease in
amphibians at lower elevations in the neotropics is not known. It also is unclear by what mechanism(s) B. dendrobatidis has emerged as a pathogenic organism. To test whether B. dendrobatidis is limited by elevation in Panamá, we sought to determine the prevalence and intensity of B. dendrobatidis in relation to anuran abundance and diversity using quantitative PCR (qPCR) analyses. Sites were situated at varying elevations,
from 45 to 1215 m, and were at varying stages of epizootic amphibian decline, including pre-epizootic, mid-epizootic, 2 years
post-epizootic, and 10 years post-epizootic. Batrachochytrium dendrobatidis was found in all sites regardless of elevation or stage of epizootic decline. Levels of prevalence and infection intensity
were comparable across all sites except at the mid-epizootic site, where both prevalence and intensity were significantly
higher than at other sites. Symptoms of chytridiomycosis and corresponding declines in amphibian populations were variably
seen at all elevations along a post-epizootic gradient. Because it is inherently difficult to prove a negative proposition,
it can neither be proven that B. dendrobatidis is truly not present where it is not detected nor proven that it is only recently arrived where it is detected. Thus, there
will always be doubts about whether B. dendrobatidis is enzootic or invasive. In any case, our results, coupled with current knowledge, suggest most clearly that the disease,
chytridiomycosis, may be novel and invasive, and that the pathogen, B. dendrobatidis either is, or is becoming, globally ubiquitous. 相似文献
4.
Loong AM Hiong KC Wong WP Chew SF Ip YK 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2012,182(2):231-245
This study aimed to identify estivation-specific gene clusters through the determination of differential gene expressions
in the liver of Protopterus annectens after 6 days of estivation in a mucus cocoon in air (normoxia) using suppression subtractive hybridization polymerase chain
reaction. Our results demonstrated that 6 days of estivation in normoxia led to up-regulation of mRNA expressions of several
genes related to urea synthesis, including carbamoyl phosphate synthetase (Cps), argininosuccinate synthetase and glutamine
synthetase. They indicate that increased urea synthesis, despite being energy-intensive, is an important adaptive response
of estivation. They also offer indirect support to the proposition that urea synthesis in this lungfish involved a Cps that
uses glutamine as a substrate. In addition, up- or down-regulation of several gene clusters occurred in the liver of P. annectens after 6 days of estivation in normoxia. These estivation-specific genes were involved in the prevention of clot formation,
activation of the lectin pathway for complement activation, conservation of minerals (e.g. iron and copper) and increased
production of hemoglobin beta. Since there were up- and down-regulation of mRNA expressions of genes related to ribosomal
proteins and translational elongation factors, there could be simultaneous increases in protein degradation and protein synthesis
during the first 6 days (the induction phase) of estivation, confirming the importance of reconstruction of protein structures
in preparation for the maintenance phase of estivation. 相似文献
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“Seaside Disease” of oysters caused by Minchinia costalis (Haplosporida, Sporozoa) produced annual mortalities on the Seaside of the Delmarva Peninsula along the middle Atlantic Coast from Chesapeake Bay to Delaware Bay, U.S.A. The May–June mortalities occurred from 1959 to 1976 without exception; deaths began in late May, peaked in June, and were usually over by July 1. The pathogen developed rapidly from March to May, and sporulation occurred in connective tissues of all organs in May and June. Exposure to a May–June enzootic was required to obtain infections. The pathogen remained subclinical until late winter of the following year. A sympatric pathogen, Minchinia nelsoni, which kills oysters extensively in lower Chesapeake Bay, was present but caused only minor mortalities. Salinities > 30 parts per thousand seem to favor M. costalis and inhibit M. nelsoni. Prevalences of both diseases in live oysters or gapers are given for 11 of the 18 years monitored. 相似文献
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Carl van Walraven 《CMAJ》2013,185(16):E755-E762
Background:
Changes in the long-term survival of people admitted to hospital is unknown. This study examined trends in 1-year survival of patients admitted to hospital adjusted for improved survival in the general population.Methods:
One-year survival after admission to hospital was determined for all adults admitted to hospital in Ontario in 1994, 1999, 2004, or 2009 by linking to vital statistics datasets. Annual survival in the general population was determined from life tables for Ontario.Results:
Between 1994 and 2009, hospital use decreased (from 8.8% to 6.3% of the general adult population per year), whereas crude 1-year mortality among people with hospital admissions increased (from 9.2% to 11.6%). During this time, patients in hospital became significantly older (median age increased from 51 to 58 yr) and sicker (the proportion with a Charlson comorbidity index score of 0 decreased from 68.2% to 60.0%), and were more acutely ill on admission (elective admissions decreased from 47.4% to 42.0%; proportion brought to hospital by ambulance increased from 16.1% to 24.8%). Compared with 1994, the adjusted odds ratio (OR) for death at 1 year in 2009 was 0.78 (95% confidence interval [CI] 0.77–0.79). However, 1-year risk of death in the general population decreased by 24% during the same time. After adjusting for improved survival in the general population, risk of death at 1 year for people admitted to hospital remained significantly lower in 2009 than in 1994 (adjusted relative excess risk 0.81, 95% CI 0.80–0.82).Interpretation:
After accounting for both the increased burden of patient sickness and improved survival in the general population, 1-year survival for people admitted to hospital increased significantly from 1994 to 2009. The reasons for this improvement cannot be determined from these data. Hospitals have a special place in most health care systems. Hospital staff care for the people with the most serious illnesses and the most vulnerable. They are frequently the location of many life-defining moments — including birth, surgery, acute medical illness and death — of many people and their families. Hospitals serve as a focus in the training of most physicians. In addition, they consume a considerable proportion of health care expenditures worldwide. 1 Given the prominence of hospitals in health care systems, measuring outcomes related to hospital care is important. In particular, the measurement of trends for outcomes of hospital care can help us to infer whether the care provided to hospital patients is improving. Previous such studies have focused on survival trends for specific diseases or patients who received treatment in specific departments. 2 – 12 None of these studies have adjusted for survival trends in the general population, the adjustment for which is important to determine whether changes in survival of patients in hospital merely reflect changes in the overall population. In this study, whether or not patient outcomes have changed over time was determined by examining trends in 1-year survival in all patients admitted to hospital, adjusting for improved survival in the general population. 相似文献7.
Andrés Mario Visintin Mauricio Daniel Beranek Maria José Amieva Juan Ramón Rosa Walter Ricardo Almirón Oscar Daniel Salomón 《Memórias do Instituto Oswaldo Cruz》2016,111(1):75-78
We report the presence of the competent vector for Leishmaniaspp,
Migonemyia migonei, and theEvandromyia
cortelezzii-sallesi complex south of its known distribution in the
central temperate region of Argentina, in the province of Córdoba. The persistence of
this phlebotomine in the northern border of the province, its association with a case
of cutaneous leishmaniasis, and the new record in the outskirts of the city of
Córdoba, the second most populated in the country, strengthens the need for regular
vector surveillance and a case detection-sensitive health system in vulnerable
regions, even in temperate climates. 相似文献
8.
Eduardo Fernandez-Duque Anthony Di Fiore Gabriel Carrillo-Bilbao 《International journal of primatology》2008,29(2):421-431
Given its broad geographical distribution, Aotus is a productive genus for comparative studies that evaluate how different ecological factors influence the morphology, behavior,
ecology, and demography of closely related species. During 18 mo we collected demographic, ranging, and activity data from
owl monkeys (Aotus vociferans) in Yasuní National Park in eastern Ecuador. To collect demographic data, we monitored the trail system several times per
week searching for groups. To characterize patterns of activity, we recorded the time when the subjects began and ended their
nocturnal activity, and we collected data on range use and daily path length during 12 full-moon and 12 new-moon night follows
of 1 radiocollared group. They ranged in size between 3 and 5 individuals (n = 4 groups). All groups were strictly nocturnal, beginning their activity between 1800 and 1900 h and finishing it between
0500 and 0600 h. The territory size of the radiocollared group was 6.3 ha. On average, the subjects traveled 645 m per night
(±286 m) and ranged farther during full-moon than new-moon nights. The owl monkeys used a small number of preferred daytime
sleeping trees. Our data conform well with previous studies of other tropical owl monkeys from Colombia and Perú. A comparison
of tropical owl monkeys with more temperate Aotus azarai from the Argentinean Gran Chaco reveals that grouping patterns, day range length, and territory size are relatively conserved
across the genus despite dramatic differences in body size and activity pattern. 相似文献
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Luciano Pamplona de Góes Cavalcanti Lia Alves Martins Mota Gustavo Porto Lustosa Mayara Carvalho Fortes Davi Alves Martins Mota Ant?nio Afonso Bezerra Lima Ivo Castelo Branco Coelho Maria Paula Gomes Mour?o 《Memórias do Instituto Oswaldo Cruz》2014,109(1):93-98
In 2009, the World Health Organization (WHO) issued a new guideline that stratifies
dengue-affected patients into severe (SD) and non-severe dengue (NSD) (with or
without warning signs). To evaluate the new recommendations, we completed a
retrospective cross-sectional study of the dengue haemorrhagic fever (DHF) cases
reported during an outbreak in 2011 in northeastern Brazil. We investigated 84
suspected DHF patients, including 45 (53.6%) males and 39 (46.4%) females. The ages
of the patients ranged from five-83 years and the median age was 29. According to the
DHF/dengue shock syndrome classification, 53 (63.1%) patients were classified as
having dengue fever and 31 (36.9%) as having DHF. According to the 2009 WHO
classification, 32 (38.1%) patients were grouped as having NSD [4 (4.8%) without
warning signs and 28 (33.3%) with warning signs] and 52 (61.9%) as having SD. A
better performance of the revised classification in the detection of severe clinical
manifestations allows for an improved detection of patients with SD and may reduce
deaths. The revised classification will not only facilitate effective screening and
patient management, but will also enable the collection of standardised surveillance
data for future epidemiological and clinical studies. 相似文献
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Six species of Gastrocopta have been identified from the Pilbara region, Western Australia, by means of comparative analyses of shell and mtDNA variation. Three of these species, Gastrocopta hedleyi, Gastrocopta larapinta and Gastrocopta servilis, have been recorded in the Pilbara for the first time. Gastrocopta sp. CW1 is probably new to science and might be endemic to the region. By contrast, Gastrocopta hedleyi, Gastrocopta larapinta and Gastrocopta mussoni are shown to be widespread. 相似文献
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D. S. Khodyrev V. I. Loginov I. V. Pronina T. P. Kazubskaya R. F. Garkavtseva E. A. Braga 《Russian Journal of Genetics》2008,44(8):983-988
The protein encoded by RAR-β2 (retinoic acid receptor) gene is a member of the superfamily, of nuclear receptors of retinoids which are involved in regulation of cell differentiation and proliferation. The level of RAR-β2 mRNA is downregulated in a number of cell lines derived from human epithelial tumors. Inactivation of the RAR-β2 gene is associated with methylation of its promoter region, which is observed in various carcinomas at a frequency of 30–70%. In renal and ovarian tumors, methylation at this region is poorly studied, the data being contradictory. We report a high methylation frequency in the gene promoter region in RCC (59%, 36/61) and a somewhat lower frequency in EOC (30%, 15/50). Methylation frequency in BC (46%, 26/56) is consistent with the published data. Significant correlation of methylation frequency in promoter region of RAR-β2 gene with RCC progression (P ≤ 0.005 by Fisher’s exact test) was established. 相似文献
14.
The distribution of the gametophytes of Asparagopsis armata in Ireland currently encompasses a 75 km radius from a seaweed farm that commercially cultivates this species. This is a smaller range than the historic distribution shows since its arrival in Ireland in 1939. Fragmentation of this alga to seed ropes at a commercial seaweed farm seems to maintain the populations of this introduced species. Without this commercial seaweed farm A. armata would probably not flourish on the Irish west coast and this farm appears to act as a source pool for the populations. The sea surface temperatures (SSTs) of Irish waters are suitable for growth, survival and asexual reproduction of the tetrasporophyte and gametophyte; however, they may not be warm enough for sexual reproduction. The effect of temperature on the life cycle and distribution are discussed. Three species, i.e., Ulva lactuca, Plocamium cartilagineum and Cryptopleura ramosa, were hosts for epiphytic A. armata in summer in over 60% of the collected samples. 相似文献
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Hilary A. Thompson Jeffrey R. White Lisa M. Pratt Peter E. Sauer 《Biogeochemistry》2016,131(1-2):17-33
Small lakes in northern latitudes represent a significant source of CH4 to the atmosphere that is predicted to increase with warming in the Arctic. Yet, whole-lake CH4 budgets are lacking as are measurements of δ13C-CH4 and δ2H-CH4. In this study, we quantify spatial variability of diffusive and ebullitive fluxes of CH4 and corresponding δ13C-CH4 and δ2H-CH4 in a small, Arctic lake system with fringing wetland in southwestern Greenland during summer. Net CH4 flux was highly variable, ranging from an average flux of 7 mg CH4 m?2 d?1 in the deep-water zone to 154 mg CH4 m?2 d?1 along the lake margin. Diffusive flux accounted for ~8.5 % of mean net CH4 flux, with plant-mediated and ebullitive flux accounting for the balance of the total net flux. Methane content of emitted ebullition was low (mean ± SD 10 ± 17 %) compared to previous studies from boreal lakes and wetlands. Isotopic composition of net CH4 emissions varied widely throughout the system, with δ13C-CH4 ranging from ?66.2 to ?55.5 ‰, and δ2H-CH4 ranging from ?345 to ?258 ‰. Carbon isotope composition of CH4 in ebullitive flux showed wider variation compared to net flux, ranging from ?69.2 to ?49.2 ‰. Dissolved CH4 concentrations were highest in the sediment and decreased up the water column. Higher concentrations of CH4 in the hypoxic deep water coincided with decreasing dissolved O2 concentrations, while methanotrophic oxidation dominated in the epilimnion based upon decreasing concentrations and increasing values of δ13C-CH4 and δ2H-CH4. The most depleted 13C- and 2H-isotopic values were observed in profundal bottom waters and in subsurface profundal sediments. Based upon paired δ13C and δ2H observations of CH4, acetate fermentation was likely the dominant production pathway throughout the system. However, isotopic ratios of CH4 in deeper sediments were consistent with mixing/transition between CH4 production pathways, indicating a higher contribution of the CO2 reduction pathway. The large spatial variability in fluxes of CH4 and in isotopic composition of CH4 throughout a single lake system indicates that the underlying mechanisms controlling CH4 cycling (production, consumption and transport) are spatially heterogeneous. Net flux along the lake margin dominated whole-lake flux, suggesting the nearshore littoral area dominates CH4 emissions in these systems. Future studies of whole-lake CH4 budgets should consider this significant spatial heterogeneity. 相似文献
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Ana PM Oliveira Rosana Gentile Arnaldo Maldonado Júnior Eduardo J Lopes Torres Silvana C Thiengo 《Memórias do Instituto Oswaldo Cruz》2015,110(6):739-744
The aim of this study was to analyse the infection dynamics ofAngiostrongylus
cantonensis in its possible intermediate hosts over two years in an urban
area in the state of Rio de Janeiro where the presence ofA.
cantonensis had been previously recorded in molluscs. Four of the seven
mollusc species found in the study were exotic.Bradybaena similaris
was the most abundant, followed byAchatina fulica,
Streptaxis sp., Subulina octona,
Bulimulus tenuissimus, Sarasinula linguaeformis
and Leptinaria unilamellata. Only A. fulica
and B. similaris were parasitised by A.
cantonensis and both presented co-infection with other helminths. The
prevalence of A. cantonensisin A. fulica was more
than 50% throughout the study. There was an inverse correlation between the
population size ofA. fulica and the prevalence of A.
cantonensis and abundance of the latter was negatively related to
rainfall. The overall prevalence of A. cantonensis in B.
similariswas 24.6%. A. fulica was the most important
intermediary host of A. cantonensis in the studied area
andB. similaris was secondary in importance for A.
cantonensis transmission dynamics. 相似文献
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A ‘kinship anthropology of politics’? Interest,the collective self,and kinship in Argentine unions★ 下载免费PDF全文
Sian Lazar 《The journal of the Royal Anthropological Institute》2018,24(2):256-274
In this article I argue for a kinship anthropology of politics, understood as a focus on the day‐to‐day imbrications of kinship and politics in a given political space, and the implications of that for the construction of political subjects. I describe kinship within shop‐floor‐level trade union delegations of state employees in Argentina in three different ways: first, languages of kinship mobilized to describe political allegiance and dispositions, especially inheritance; second, family connections in recruitment and activism; and, third, practices of kinning as relatedness. The combination of these three kinship modes creates the union as kin group, and enables it to act on the world politically in order to transform it. 相似文献
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Explants obtained from in vitro-propagated plantlets of two potato cultivars, Shepody and Atlantic, were treated with five doses of γ-radiation (0, 2, 4, 6 and 8 Gy) to investigate the stimulating effects of low irradiation on the production and quality of microtubers in vitro. Microtubers of both cultivars treated with γ-radiation initiated 5 d earlier than in the non-irradiated control. The whole period of microtuberization was prolonged by 10 – 15 d with 4, 6 and 8 Gy irradiation treatment for cv. Atlantic. Irradiation of the plantlets (4 Gy) led to a significant increase not only in the microtuber number (116.7 and 34.5 % over the control) but also in the fresh mass (77.6 and 23.2 % in Shepody and Atlantic, respectively). Low dose irradiation (2 – 4 Gy) increased the starch content of microtubers. High doses (6 – 8 Gy) enhanced ascorbic acid and reducing sugar contents. 4 – 6 Gy doses also effectively increased the protein contents of microtubers. 相似文献