18 research outputs found
Relative Impacts of Adult Movement, Larval Dispersal and Harvester Movement on the Effectiveness of Reserve Networks
Movement of individuals is a critical factor determining the effectiveness of
reserve networks. Marine reserves have historically been used for the management
of species that are sedentary as adults, and, therefore, larval dispersal has
been a major focus of marine-reserve research. The push to use marine reserves
for managing pelagic and demersal species poses significant questions regarding
their utility for highly-mobile species. Here, a simple conceptual
metapopulation model is developed to provide a rigorous comparison of the
functioning of reserve networks for populations with different admixtures of
larval dispersal and adult movement in a home range. We find that adult movement
produces significantly lower persistence than larval dispersal, all other
factors being equal. Furthermore, redistribution of harvest effort previously in
reserves to remaining fished areas (âfishery squeezeâ) and fishing
along reserve borders (âfishing-the-lineâ) considerably reduce
persistence and harvests for populations mobile as adults, while they only
marginally changes results for populations with dispersing larvae. Our results
also indicate that adult home-range movement and larval dispersal are not simply
additive processes, but rather that populations possessing both modes of
movement have lower persistence than equivalent populations having the same
amount of âtotal movementâ (sum of larval and adult movement spatial
scales) in either larval dispersal or adult movement alone
Differential Effects of Hypoxia-Ischemia on Phosphorylation of the N-Methyl-<i>D</i>-Aspartate Receptor in One- and Three-Week-Old Rats
Ethanol induced alterations in plasma membrane protein phosphorylation of neurons and astrocytes
Dementia and mild cognitive impairment in patients with Parkinson's disease DemĂȘncia e transtorno cognitivo leve em pacientes com doença de Parkinson
The objective of this research was to assess the occurrence of cognitive impairment in 32 individuals (average age: 67.2 years old) with Parkinson' disease (PD). Procedures: clinical-neurological assessment; modified Hoehn and Yahr staging scale (HYS); standard neuropsychological battery of CERAD (Consortium to Establish a Registry for Alzheimer' Disease); Pfeffer questionnaire; and Clinical Dementia Rating. A comparison was made with a control group (CG), consisting of 26 individuals with similar age and educational level but without cognitive impairment. The PD patients showed an inferior performance in the CERAD battery when compared to the CG. Three PD sub-groups were characterised according to cognition: no cognitive impairment - 15 cases; mild cognitive impairment - 10; dementia - 7 cases. There was a significant association between motor disability (HYS) and the occurrence of dementia. Dementia and mild cognitive impairment frequently occur in PD patients and should be investigated in a routine way.<br>O objetivo desta pesquisa foi avaliar a ocorrĂȘncia de dĂ©ficits cognitivos em 32 indivĂduos (idade mĂ©dia: 67,2 anos) com doença de Parkinson (DP). Procedimentos: avaliação clĂnico-neurolĂłgica, escala de Hoehn and Yahr modificada (EHY), bateria neurospicolĂłgica do CERAD (Consortium to Establish a Registry for Alzheimer' Disease), questionĂĄrio de Pfeffer e escore clĂnico da demĂȘncia (Clinical Dementia Rating). Foi feita comparação com grupo controle (GC) de 26 indivĂduos sem declĂnio cognitivo, com idade e nĂvel educacional similares. Os pacientes com DP tiveram desempenho inferior na bateria CERAD, quando comparados ao do GC. Foram caracterizados 3 subgrupos com PD segundo a cognição: sem dĂ©ficits cognitivos - 15 casos; transtorno cognitivo leve - 10; demĂȘncia - 7 casos. Houve associação entre comprometimento motor e ocorrĂȘncia de demĂȘncia. DemĂȘncia e transtorno cognitivo leve sĂŁo freqĂŒentes em pacientes com DP e devem ser investigados de modo rotineiro
Wild mallards have more ââgoose-likeââ bills than their ancestors : a case of anthropogenic influence?
Wild populations of the worldâs most common dabbling duck, the mallard (Anas platyrhynchos), run the risk of genetic introgression by farmed conspecifics released for hunting purposes. We tested whether bill morphology of free-living birds has changed since large-scale releases of farmed mallards started. Three groups of mallards from Sweden, Norway and Finland were compared: historical wild (before large-scale releases started), present-day wild, and present-day farmed. Higher density of bill lamellae was observed in historical wild mallards (only males). Farmed mallards had wider bills than present-day and historical wild ones. Present-day wild and farmed mallards also had higher and shorter bills than historical wild mallards. Present-day mallards thus tend to have more âgoose-likeâ bills (wider, higher, and shorter) than their ancestors. Our study suggests that surviving released mallards affect morphological traits in wild population by introgression. We discuss how such anthropogenic impact may lead to a maladapted and genetically compromised wild mallard population. Our study system has bearing on other taxa where large-scale releases of conspecifics with âalien genesâ may cause a cryptic invasive process that nevertheless has fitness consequences for individual birds