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Estimates seasonal rates of ruffed grouse mortality due to predation and hunting. Heavily hunted public lands vs. lightly hunted private lands; Hunting mortality as additive or compensatory; Details of study.

Studies the habitat selection by spotted owls during natal dispersal in western Oregon. Forest fragmentation; Probability of mortality of juvenile spotted owls; Selection of closed-canopy forests; Open sampling stands; Correlation of clearcuts and successful natal dispersal.

Examines the hypothesis indicating that an inherent risk of dispersal is an increased probability of death. Use of ruffed grouse as experimental animal; Calculation of mortality estimates the transience and colonization periods; Juvenile versus adults; Male versus female.

Climate change is having profound impacts on animal populations, and shifts in geographic range are predicted in response. Shifts that result in range overlap between previously allopatric congeneric species may have consequences for biodiversity through interspecific competition, hybridization, and genetic introgression. Harbor seals ( Phoca vitulina) and spotted seals ( Phoca largha) are parapatric sibling species and areas of co-occurrence at the edges of their range, such as Bristol Bay, Alaska, offer a unique opportunity to explore ecological separation and discuss potential consequences of increased range overlap resulting from retreating sea ice. Using telemetry and genetic data from 14 harbor seals and six spotted seals, we explored the ecological and genetic separation of the two species by comparing their utilization distributions, distance from haul-out, dive behavior (e.g., depth, duration, focus), and evidence of hybridization. Firstly, we show that harbor and spotted seals, which cannot be visually distinguished definitively in all cases, haul-out together side by side in Bristol Bay from late summer to early winter. Secondly, we observed subtle rather than pronounced differences in ranging patterns and dive behavior during this period. Thirdly, most spotted seals in this study remained close to shore in contrast to what is known of the species in more northern areas, and lastly, we did not find any evidence of hybridization. The lack of distinct ecological separation in this area of sympatry suggests that interspecific competition could play an important role in the persistence of these species, particularly if range overlap will increase as a result of climate-induced range shifts and loss of spotted seal pagophilic breeding habitat. Our results also highlight the added complexities in monitoring these species in areas of suspected overlap, as they cannot easily be distinguished without genetic analysis. Predicted climate-induced environmental change will likely influence the spatial and temporal extent of overlap in these two sibling species. Ultimately, this may alter the balance between current isolating mechanisms with consequences for species integrity and fitness. [ABSTRACT FROM AUTHOR]

Satellite telemetry devices collect valuable information concerning the sites visited by animals, including the location of central places like dens, nests, rookeries, or haul-outs. Existing methods for estimating the location of central places from telemetry data require user-specified thresholds and ignore common nuances like measurement error. We present a fully model-based approach for locating central places from telemetry data that accounts for multiple sources of uncertainty and uses all of the available locational data. Our general framework consists of an observation model to account for large telemetry measurement error and animal movement, and a highly flexible mixture model specified using a Dirichlet process to identify the location of central places. We also quantify temporal patterns in central place use by incorporating ancillary behavioral data into the model; however, our framework is also suitable when no such behavioral data exist. We apply the model to a simulated data set as proof of concept. We then illustrate our framework by analyzing an Argos satellite telemetry data set on harbor seals ( Phoca vitulina) in the Gulf of Alaska, a species that exhibits fidelity to terrestrial haul-out sites. [ABSTRACT FROM AUTHOR]

Background Functional magnetic resonance imaging ( fMRI) has been used to evaluate the long-term consequences of early exposure to neurotoxic agents. fMRI shows that different patterns of brain activation occur in ethanol-exposed subjects performing a go/no-go response inhibition task. Pharmacologically, ethanol and general anesthetics have similar receptor-level activity in the brain. This study utilizes fMRI to examine brain activation patterns in children exposed to general anesthesia and surgery during early brain development. Methods After obtaining Nationwide Children's Hospital IRB approval, a surgical database was utilized to identify children aged 10-17 years with a history of at least 1 h of exposure to general anesthetics and surgery when they were between 0 and 24 months of age. Age- and gender-matched children without anesthesia exposure were recruited as a control group. All subjects were scanned while being presented with a go/no-go response inhibition task. Reaction time and accuracy data were acquired, and the blood-oxygen-level-dependent ( BOLD) fMRI signal was measured as a biomarker for regional neuronal activity. Results There were no differences in terms of performance accuracy and response time. The analysis did not reveal any significant activation differences in the primary region of interest (prefrontal cortex and caudate nucleus); however, activation differences were seen in other structures, including the cerebellum, cingulate gyrus, and paracentral lobule. Conclusions Early anesthetic exposure and surgery did not affect accuracy, response time, or activation patterns in the primary region of interest during performance of the task. Intergroup differences in activation patterns in other areas of the brain were observed, and the significance of these findings is unknown. fMRI appears to be a useful tool in evaluating the long-term effects of early exposure to general anesthesia. [ABSTRACT FROM AUTHOR]

Multiple factors complicate the analysis of animal telemetry location data. Recent advancements address issues such as temporal autocorrelation and telemetry measurement error, but additional challenges remain. Difficulties introduced by complicated error structures or barriers to animal movement can weaken inference. We propose an approach for obtaining resource selection inference from animal location data that accounts for complicated error structures, movement constraints, and temporally autocorrelated observations. We specify a model for telemetry data observed with error conditional on unobserved true locations that reflects prior knowledge about constraints in the animal movement process. The observed telemetry data are modeled using a flexible distribution that accommodates extreme errors and complicated error structures. Although constraints to movement are often viewed as a nuisance, we use constraints to simultaneously estimate and account for telemetry error. We apply the model to simulated data, showing that it outperforms common ad hoc approaches used when confronted with measurement error and movement constraints. We then apply our framework to an Argos satellite telemetry data set on harbor seals (Phoca vitulina) in the Gulf of Alaska, a species that is constrained to move within the marine environment and adjacent coastlines. [ABSTRACT FROM AUTHOR]