Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Conserv Biol ; 36(4): e13918, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35554972

RESUMO

The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400-480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993-2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations.


La paloma rosada (Nesoenas mayeri) es una especie endémica de Mauricio que se ha recuperado impresionantemente después de un grave cuello de botella poblacional a principios de la década de 1970 que duró hasta inicios de la década de 1990. Antes de este cuello de botella se había establecido una población ex situ de la cual se liberaban individuos reproducidos en cautiverio a las subpoblaciones en libertad para incrementar la variación genética y el tamaño poblacional. Este rescate de conservación derivó en una recuperación rápida de la población (400-480 individuos) y la especie cambió positivamente de categoría dos veces en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza (UICN). Analizamos los impactos del cuello de botella y el rescate genético sobre la variación genética neutral durante y después de la recuperación poblacional (de 1993 a 2008) mediante secuenciación RAD, análisis de microsatélites y análisis genéticos cuantitativos de los datos del libro genealógico de 1112 aves ubicadas en zoológicos de Europa y los Estados Unidos. Usamos simulaciones por computadora para estudiar los cambios pronosticados en la variación genética y en la viabilidad poblacional del pasado hacia el futuro. La variación genética declinó rápidamente, a pesar de la recuperación poblacional, y el tamaño efectivo de la población fue aproximadamente un orden de magnitud más pequeño que el tamaño del censo. La especie contó con una carga genética elevada de casi 15 equivalentes letales para la longevidad. Nuestras simulaciones pronostican que la endogamia continua probablemente resultará en un incremento en la expresión de mutaciones deletéreas (es decir, una carga realizada elevada) y en una depresión endogámica severa. Sin acciones continuas para la conservación, es probable que la paloma rosada esté extinta en vida libre dentro de cien años. El rescate de conservación de la paloma rosada ha sido fundamental en la recuperación de la población silvestre; sin embargo, se requiere de un rescate genético adicional con las aves de reproducción en cautiverio de los zoológicos para recuperar la variación perdida, reducir la expresión de la variación deletérea dañina y prevenir la extinción. El uso de la genómica y los datos modelados puede orientar las valoraciones de la UICN sobre la viabilidad y el riesgo de extinción de las especies, además de que ayuda en la evaluación de la dependencia que tienen las poblaciones de la conservación.


Assuntos
Aves , Conservação dos Recursos Naturais , Animais , Aves/genética , Espécies em Perigo de Extinção , Europa (Continente) , Variação Genética , Genômica , Densidade Demográfica
2.
Neuropsychol Rehabil ; 29(2): 251-272, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28116988

RESUMO

Hemispatial neglect is a severe cognitive condition frequently observed after a stroke, associated with unawareness of one side of space, disability and poor long-term outcome. Visuomotor feedback training (VFT) is a neglect rehabilitation technique that involves a simple, inexpensive and feasible training of grasping-to-lift rods at the centre. We compared the immediate and long-term effects of VFT vs. a control training when delivered in a home-based setting. Twenty participants were randomly allocated to an intervention (who received VFT) or a control group (n = 10 each). Training was delivered for two sessions by an experimenter and then patients self-administered it for 10 sessions over two weeks. Outcome measures included the Behavioural Inattention Test (BIT), line bisection, Balloons Test, Landmark task, room description task, subjective straight-ahead pointing task and the Stroke Impact Scale. The measures were obtained before, immediately after the training sessions and after four-months post-training. Significantly greater short and long-term improvements were obtained after VFT when compared to control training in line bisection, BIT and spatial bias in cancellation. VFT also produced improvements on activities of daily living. We conclude that VFT is a feasible, effective, home-based rehabilitation method for neglect patients that warrants further investigation with well-designed randomised controlled trials on a large sample of patients.


Assuntos
Atenção/fisiologia , Retroalimentação Sensorial/fisiologia , Transtornos da Percepção/reabilitação , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/complicações , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/etiologia , Percepção Espacial/fisiologia , Resultado do Tratamento
3.
Mol Ecol ; 24(16): 4269-85, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26172573

RESUMO

Invasive species present a major threat to global biodiversity. Understanding genetic patterns and evolutionary processes that reinforce successful establishment is paramount for elucidating mechanisms underlying biological invasions. Among birds, the ring-necked parakeet (Psittacula krameri) is one of the most successful invasive species, established in over 35 countries. However, little is known about the evolutionary genetic origins of this species and what population genetic signatures tell us about patterns of invasion. We reveal the ancestral origins of populations across the invasive range and explore the potential influence of climate and propagule pressure from the pet trade on observed genetic patterns. Ring-necked parakeet samples representing the ancestral native range (n = 96) were collected from museum specimens, and modern samples from the invasive range (n = 855) were gathered from across Europe, Mauritius and Seychelles, and sequenced for two mitochondrial DNA markers comprising 868 bp of cytochrome b and control region, and genotyped at 10 microsatellite loci. Invasive populations comprise birds that originate predominantly from Pakistan and northern areas of India. Haplotypes associated with more northerly distribution limits in the ancestral native range were more prevalent in invasive populations in Europe, and the predominance of Asian haplotypes in Europe is consistent with the higher number of Asian birds transported by the pet trade outside the native range. Successful establishment of invasive species is likely to be underpinned by a combination of environmental and anthropogenic influences.


Assuntos
Clima , Genética Populacional , Espécies Introduzidas , Periquitos/genética , Animais , Teorema de Bayes , Comércio , DNA Mitocondrial/genética , Europa (Continente) , Marcadores Genéticos , Genótipo , Haplótipos , Maurício , Animais de Estimação , Análise de Sequência de DNA , Seicheles
4.
Evol Appl ; 17(5): e13701, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38784837

RESUMO

Genetic diversity underpins evolutionary potential that is essential for the long-term viability of wildlife populations. Captive populations harbor genetic diversity potentially lost in the wild, which could be valuable for release programs and genetic rescue. The Critically Endangered Arabian leopard (Panthera pardus nimr) has disappeared from most of its former range across the Arabian Peninsula, with fewer than 120 individuals left in the wild, and an additional 64 leopards in captivity. We (i) examine genetic diversity in the wild and captive populations to identify global patterns of genetic diversity and structure; (ii) estimate the size of the remaining leopard population across the Dhofar mountains of Oman using spatially explicit capture-recapture models on DNA and camera trap data, and (iii) explore the impact of genetic rescue using three complementary computer modeling approaches. We estimated a population size of 51 (95% CI 32-79) in the Dhofar mountains and found that 8 out of 25 microsatellite alleles present in eight loci in captive leopards were undetected in the wild. This includes two alleles present only in captive founders known to have been wild-sourced from Yemen, which suggests that this captive population represents an important source for genetic rescue. We then assessed the benefits of reintroducing novel genetic diversity into the wild population as well as the risks of elevating the genetic load through the release of captive-bred individuals. Simulations indicate that genetic rescue can improve the long-term viability of the wild population by reducing its genetic load and realized load. The model also suggests that the genetic load has been partly purged in the captive population, potentially making it a valuable source population for genetic rescue. However, the greater loss of its genetic diversity could exacerbate genomic erosion of the wild population during a rescue program, and these risks and benefits should be carefully evaluated. An important next step in the recovery of the Arabian leopard is to empirically validate these conclusions, implement and monitor a genomics-informed management plan, and optimize a strategy for genetic rescue as a tool to recover Arabia's last big cat.

5.
Cereb Cortex ; 19(11): 2616-24, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19282456

RESUMO

It is well established that patients with hemispatial neglect present with severe visuospatial impairments, but studies that have directly investigated visuomotor control have revealed diverging results, with some studies showing that neglect patients perform relatively better on such tasks. The present study compared the visuomotor performance of patients with and without neglect after right-hemisphere stroke with those of age-matched controls. Participants were asked to point either directly towards targets or halfway between two stimuli, both with and without visual feedback during movement. Although we did not find any neglect-specific impairment, both patient groups showed increased reaction times to leftward stimuli as well as decreased accuracies for open loop leftward reaches. We argue that these findings agree with the view that neglect patients code spatial parameters for action veridically. Moreover, we suggest that lesions in the right hemisphere may cause motor deficits irrespective of the presence of neglect and we performed an initial voxel-lesion symptom analysis to assess this. Lesion-symptom analysis revealed that the reported deficits did not result from damage to neglect-associated areas alone, but were further associated with lesions to crucial nodes in the visuomotor control network (the basal ganglia as well as occipito-parietal and frontal areas).


Assuntos
Potenciais Evocados , Córtex Motor/fisiopatologia , Destreza Motora , Movimento , Reconhecimento Visual de Modelos , Transtornos da Percepção/fisiopatologia , Análise e Desempenho de Tarefas , Córtex Visual/fisiopatologia , Idoso , Feminino , Humanos , Masculino
6.
PLoS One ; 15(11): e0242726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33196675

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0226064.].

7.
J Hosp Palliat Nurs ; 21(2): 139-143, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30688800

RESUMO

In 2011, the Veterans Health Administration mandated that Veterans Affairs (VA) Medical Centers develop and implement a policy that allowed registered nurses (RNs) and advanced practice registered nurses (APRNs) to pronounce the death of residents who die in Veterans Affairs community living centers, previously known as nursing homes, provided that there is a written do-not-resuscitate order in their medical record. The purpose of this quality improvement project was to determine the extent to which the implementation of the RN/APRN death pronouncement policy affected death pronouncement time for residents who die after 5 PM and before 7:30 AM, on weekends and holidays. This project is significant because the previous physician-only death pronouncement policy was found to cause unnecessary delays in death pronouncement. A chart review of the medical records of all veterans' deaths pronounced by physicians 3 years before the implementation of the policy and 4 years after the RN/APRN policy was reviewed and implemented. The data analysis was conducted using descriptive analysis. A significant difference was found in the results (P < .05). The maximum for prepolicy deaths was 125 minutes. The maximum for postpolicy deaths was 7 minutes. The results supported the assumption that RN/APRN pronounced death without delay.


Assuntos
Prática Avançada de Enfermagem/normas , Papel do Profissional de Enfermagem , Casas de Saúde , Ordens quanto à Conduta (Ética Médica) , Veteranos , Enfermagem de Cuidados Paliativos na Terminalidade da Vida , Humanos , Melhoria de Qualidade , Estados Unidos , United States Department of Veterans Affairs/normas , Virginia
8.
PLoS One ; 14(12): e0226064, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31869373

RESUMO

Flight loss has evolved independently in numerous island bird lineages worldwide, and particularly in rails (Rallidae). The Aldabra white-throated rail (Dryolimnas [cuvieri] aldabranus) is the last surviving flightless bird in the western Indian Ocean, and the only living flightless subspecies within Dryolimnas cuvieri, which is otherwise volant across its extant range. Such a difference in flight capacity among populations of a single species is unusual, and could be due to rapid evolution of flight loss, or greater evolutionary divergence than can readily be detected by traditional taxonomic approaches. Here we used genetic and morphological analyses to investigate evolutionary trajectories of living and extinct Dryolimnas cuvieri subspecies. Our data places D. [c.] aldabranus among the most rapid documented avian flight loss cases (within an estimated maximum of 80,000-130,000 years). However, the unusual intraspecific variability in flight capacity within D. cuvieri is best explained by levels of genetic divergence, which exceed those documented between other volant taxa versus flightless close relatives, all of which have full species status. Our results also support consideration of Dryolimnas [cuvieri] aldabranus as sufficiently evolutionary distinct from D. c. cuvieri to warrant management as an evolutionary significant unit. Trait variability among closely related lineages should be considered when assessing conservation status, particularly for traits known to influence vulnerability to extinction (e.g. flightlessness).


Assuntos
Evolução Biológica , Aves/classificação , Animais , Aves/genética , Aves/fisiologia , Conservação dos Recursos Naturais , DNA/química , DNA/isolamento & purificação , DNA/metabolismo , Voo Animal , Variação Genética , Haplótipos , Oceano Índico , Ilhas , Filogenia , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA