RESUMO
Given the rapid loss of biodiversity as consequence of climate change, greater knowledge of ecophysiological and natural history traits are crucial to determine which environmental factors induce stress and drive the decline of threatened species. Liolaemus montanezi (Liolaemidae), a xeric-adapted lizard occurring only in a small geographic range in west-central Argentina, constitutes an excellent model for studies on the threats of climate change on such microendemic species. We describe field data on activity patterns, use of microhabitat, behavioral thermoregulation, and physiology to produce species distribution models (SDMs) based on climate and ecophysiological data. Liolaemus montanezi inhabits a thermally harsh environment which remarkably impacts their activity and thermoregulation. The species shows a daily bimodal pattern of activity and mostly occupies shaded microenvironments. Although the individuals thermoregulate at body temperatures below their thermal preference they avoid high-temperature microenvironments probably to avoid overheating. The population currently persists because of the important role of the habitat physiognomy and not because of niche tracking, seemingly prevented by major rivers that form boundaries of their geographic range. We found evidence of habitat opportunities in the current range and adjacent areas that will likely remain suitable to the year 2070, reinforcing the relevance of the river floodplain for the species' avoidance of extinction.
Assuntos
Adaptação Fisiológica , Regulação da Temperatura Corporal/fisiologia , Espécies em Perigo de Extinção , Lagartos/fisiologia , Animais , Argentina , Temperatura Corporal , Mudança Climática , Conservação dos Recursos Naturais/métodos , Ecossistema , Feminino , Temperatura Alta , MasculinoRESUMO
Lizard activity and endurance of cold climate is regulated by several factors such as evolutionary potential, acclimatization capacity, physiological tolerance, and locomotion among thermally advantageous microenvironments. Liolaemus lineomaculatus, a lizard inhabiting a wide range of cold environments in Patagonia, provides an excellent model to test interpopulation variability in thermal performance curves (TPCs) and usage of microhabitats. We obtained critical thermal minima and maxima, and performed running trials at eight temperatures using lizards from both a temperate-site (high-altitude) population at 42° S and a cold-site population at 50° S. The availability of environmental temperatures for running performance in open ground and in potential lizard refuges were recorded, and showed that lizards in the temperate site had a greater availability of thermal environments offering temperatures conducive to locomotion. Generalized additive mixed models showed that the two populations displayed TPCs of different shapes in 0.15 m runs at temperatures near their optimal temperature, indicating a difference in thermal sensitivity at high temperatures. However, the rest of the locomotor parameters remained similar between Liolaemus lineomaculatus from thermal and ecological extremes of their geographic distribution and this may partly explain their ability to endure a cold climate.
Assuntos
Lagartos/fisiologia , Corrida/fisiologia , Aclimatação/fisiologia , Animais , Evolução Biológica , Regulação da Temperatura Corporal , Clima Frio , Temperatura Baixa , Temperatura Alta , Locomoção/fisiologia , Filogenia , TemperaturaRESUMO
Astrovirus infections were detected by enzyme immunoassay in 12 (5%) of 251 stool samples from children with gastroenteritis from Bogota, Colombia. In addition, astroviruses were detected by reverse transcription-PCR in 3 (10%) of 29 stool samples negative for other enteric pathogens collected in Caracas, Venezuela, from children with gastroenteritis. Astrovirus type 1 was the most frequently detected virus.
Assuntos
Infecções por Astroviridae/epidemiologia , Gastroenterite/epidemiologia , Mamastrovirus/classificação , Mamastrovirus/genética , Adolescente , Adulto , Distribuição por Idade , Infecções por Astroviridae/diagnóstico , Infecções por Astroviridae/virologia , Criança , Pré-Escolar , Colômbia/epidemiologia , DNA Viral/genética , Fezes/virologia , Gastroenterite/diagnóstico , Gastroenterite/virologia , Humanos , Lactente , Recém-Nascido , Mamastrovirus/isolamento & purificação , Pessoa de Meia-Idade , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Venezuela/epidemiologiaRESUMO
The Vertigo Symptom Scale (VSS) was designed to assess and differentiate symptoms of: (a) balance disorder; and (b) somatic anxiety and autonomic arousal in patients complaining of dizziness and vertigo. Although it has been translated for use in countries other than the UK, where it was originally developed, its validity in different languages and cultures has not previously been evaluated. This study examined the structure, reliability, and discriminative power of a Spanish translation of the VSS administered to a Mexican sample of 172 dizzy patients and 40 healthy controls. Scores on the two subscales of the VSS not only discriminated between patients and controls, but were also sensitive to differences between patient groups classified on the basis of diagnosis, test results, and occupational disability. The pattern of intercorrelations between symptoms, anxiety, depression, and handicap in the Mexican sample was almost identical to that observed in the original UK sample.