Demographic assessment of the blue crab (Callinectes sapidus) in Chesapeake Bay using extractable lipofuscins as age markers

The blue crab (Callinectes sapidus) plays an important economic and ecological role in estuaries and coastal habitats from the Gulf of Mexico to the east coast of North America, but demographic assessments are limited by length-based methods. We applied an alternative aging method using biochemical measures of metabolic byproducts (lipofuscins) sequestered in the neural tissue of eyestalks to examine population age structure. From Chesapeake Bay, subsamples of animals collected from the 1998–99 (n=769) and 1999–2000 (n=367) winter dredge surveys were collected and lipofuscin was measured. Modal analysis of the lipofuscin index provided separation into three modes, whereas carapace-width data collected among the same individuals showed two broad modes. Lipofuscin modal analysis indicated that most adults (carapace width >120 mm) were <2 years old. The results indicate that use of extractable lipofuscin can provide a more accurate and better resolved estimation of demographic structure of blue crab populations in the field than size alone.

Differential population structuring and demographic history of two closely related fish species, Japanese sea bass (Lateolabrax japonicus) and spotted sea bass (Lateolabrax maculatus) in Northwestern Pacific

The Quaternary cold periods in the Northwestern Pacific are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in marine fishes. To estimate the demographic history and genetic structure of Lateolabrax macula

Prevalence of overweight and obesity among nurses in Scotland: A cross-sectional study using the Scottish Health Survey.

Background Increasing prevalence of overweight and obesity represents a global pandemic. As the largest occupational group in international healthcare systems nurses are at the forefront of health promotion to address this pandemic. However, nurses own health behaviours are known to influence the extent to which they engage in health promotion and the public's confidence in advice offered. Estimating the prevalence of overweight and obesity among nurses is therefore important. However, to date, prevalence estimates have been based on non-representative samples and internationally no studies have compared prevalence of overweight and obesity among nurses to other healthcare professionals using representative data. Objectives To estimate overweight and obesity prevalence among nurses in Scotland, and compare to other healthcare professionals and those working in non-heath related occupations. Design Cross-sectional study using a nationally representative sample of five aggregated annual rounds (2008-2012) of the Scottish Health Survey. Setting Scotland. Participants: 13,483 adults aged 17 to 65 indicating they had worked in the past 4 weeks, classified in four occupational groups: nurses (n = 411), other healthcare professionals (n = 320), unqualified care staff (n = 685), and individuals employed in non-health related occupations (n = 12,067). Main outcome measures: Prevalence of overweight and obesity defined as Body Mass Index ≥ 25.0. Methods Estimates of overweight and obesity prevalence in each occupational group were calculated with 95% confidence intervals (CI). A logistic regression model was then built to compare the odds of being overweight or obese with not being overweight or obese for nurses in comparison to the other occupational categories. Data were analysed using SAS 9.1.3. Results 69.1% (95% CI 64.6,73.6) of Scottish nurses were overweight or obese. Prevalence of overweight and obesity was higher in nurses than other healthcare professionals (51.3%, CI 45.8,56.7), unqualified care staff (68.5%, CI 65.0,72.0) and those in non-health related occupations (68.9%, CI 68.1,69.7). A logistic regression model adjusted for socio-demographic composition indicated that, compared to nurses, the odds of being overweight or obese was statistically significantly lower for other healthcare professionals (Odds Ratio [OR] 0.45, CI 0.33,0.61) and those in non-health related occupations (OR 0.78, CI 0.62,0.97). Conclusions Prevalence of overweight and obesity among Scottish nurses is worryingly high, and significantly higher than those in other healthcare professionals and non-health related occupations. High prevalence of overweight and obesity potentially harms nurses’ own health and hampers the effectiveness of nurses’ health promotion role. Interventions are therefore urgently required to address overweight and obesity among the Scottish nursing workforce.

Deformable Prototypes for Encoding Shape Categories in Image Databases

We describe a method for shape-based image database search that uses deformable prototypes to represent categories. Rather than directly comparing a candidate shape with all shape entries in the database, shapes are compared in terms of the types of nonrigid deformations (differences) that relate them to a small subset of representative prototypes. To solve the shape correspondence and alignment problem, we employ the technique of modal matching, an information-preserving shape decomposition for matching, describing, and comparing shapes despite sensor variations and nonrigid deformations. In modal matching, shape is decomposed into an ordered basis of orthogonal principal components. We demonstrate the utility of this approach for shape comparison in 2-D image databases.

Cortical Learning of Recognition Categories: A Resolution of the Exemplar Vs. Prototype Debate

Do humans and animals learn exemplars or prototypes when they categorize objects and events in the world? How are different degrees of abstraction realized through learning by neurons in inferotemporal and prefrontal cortex? How do top-down expectations influence the course of learning? Thirty related human cognitive experiments (the 5-4 category structure) have been used to test competing views in the prototype-exemplar debate. In these experiments, during the test phase, subjects unlearn in a characteristic way items that they had learned to categorize perfectly in the training phase. Many cognitive models do not describe how an individual learns or forgets such categories through time. Adaptive Resonance Theory (ART) neural models provide such a description, and also clarify both psychological and neurobiological data. Matching of bottom-up signals with learned top-down expectations plays a key role in ART model learning. Here, an ART model is used to learn incrementally in response to 5-4 category structure stimuli. Simulation results agree with experimental data, achieving perfect categorization in training and a good match to the pattern of errors exhibited by human subjects in the testing phase. These results show how the model learns both prototypes and certain exemplars in the training phase. ART prototypes are, however, unlike the ones posited in the traditional prototype-exemplar debate. Rather, they are critical patterns of features to which a subject learns to pay attention based on past predictive success and the order in which exemplars are experienced. Perturbations of old memories by newly arriving test items generate a performance curve that closely matches the performance pattern of human subjects. The model also clarifies exemplar-based accounts of data concerning amnesia.

Low demographic variability in wild primate populations: fitness impacts of variation, covariation, and serial correlation in vital rates.

In a stochastic environment, long-term fitness can be influenced by variation, covariation, and serial correlation in vital rates (survival and fertility). Yet no study of an animal population has parsed the contributions of these three aspects of variability to long-term fitness. We do so using a unique database that includes complete life-history information for wild-living individuals of seven primate species that have been the subjects of long-term (22-45 years) behavioral studies. Overall, the estimated levels of vital rate variation had only minor effects on long-term fitness, and the effects of vital rate covariation and serial correlation were even weaker. To explore why, we compared estimated variances of adult survival in primates with values for other vertebrates in the literature and found that adult survival is significantly less variable in primates than it is in the other vertebrates. Finally, we tested the prediction that adult survival, because it more strongly influences fitness in a constant environment, will be less variable than newborn survival, and we found only mixed support for the prediction. Our results suggest that wild primates may be buffered against detrimental fitness effects of environmental stochasticity by their highly developed cognitive abilities, social networks, and broad, flexible diets.

The abstraction of form in semantic categories.

Undergraduates were asked to generate a name for a hypothetical new exemplar of a category. They produced names that had the same numbers of syllables, the same endings, and the same types of word stems as existing exemplars of that category. In addition, novel exemplars, each consisting of a nonsense syllable root and a prototypical ending, were accurately assigned to categories. The data demonstrate the abstraction and use of surface properties of words.

Biological and demographic response of aphids Nasonovia ribisnigri (Mosley) and Aulacorthum solani (Kaltenbach) (Hemiptera : Aphididae) on lettuce commercial cultivars under laboratory conditions

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Biological and demographic response of aphids Nasonovia ribisnigri (Mosley) and Aulacorthum solani (Kaltenbach) (Hemiptera : Aphididae) on lettuce commercial cultivars under laboratory conditions

p.17-24