Intraspecific comparison of California sea lion (Zalophus californianus) diet assessed using fecal and stable isotope analyses

The diet of juvenile and adult female California sea lions (Zalophus californianus (Lesson, 1828)) at San Miguel Island, California, was estimated and compared using fecal and stable isotope analyses to determine dietary differences by age. Fecal samples were collected during 2002-2006 and prey hard parts were identified. Stable carbon (d13C) and nitrogen (d15N) isotope values were determined from plasma and fur obtained from yearlings, 2- to 3-yr old juveniles, and adult females during 2005 and 2006. Juveniles ate more than 15 prey taxa, whereas adult females consumed more than 33 prey taxa. Relative importance of prey was determined using percent requency of occurrence (%FO). Engraulis mordax (Girard, 1854), Sardinops sagax Jenyns, 1842), Merluccius productus (Ayres, 1855), Sebastes spp. (Cuvier, 1829), and Loligo opalescens (Berry, 1911) were the most frequently occurring (%FO > 10%) prey in the fecal samples of both juvenile and adult female sea lions, although their mportance varied between age groups. Only yearlings had significantly different isotopic values than older conspecifics, indicating that older juveniles were feeding at a similar trophic level, and in similar habitats, as adult females. Whereas each method had biases and uncertainties, combining the two methods provided a better understanding of the diet of California sea lions and intraspecific differences.Ciencias marinasPD

Establishment and dynamics of the balsam fir seedling bank in old forests of northeastern Quebec

This study examines balsam fir (Abies balsamea (L.) Mill.) recruitment in old fir stands. Studying the regeneration of these stands is essential to understand the regeneration dynamic of the species in the absence of standdestroying disturbances. The objectives were (1) to obtain substrate-seedling associations for different age-classes and according to the presence or absence of adventitious roots; (2) to evaluate the contribution of the seed rain to seedling recruitment; (3) to re-examine age structures using the most appropriate method that minimizes estimation errors due to the presence of adventitious roots. A total of 90 quadrats (1 m2) were established along transects. In each quadrat, subtrates were characterized (type and topography) and their area was estimated. All balsam fir seedlings (<50 cm tall) present in the quadrats were located, harvested whole (root and shoot), and described (age, height, presence of adventitious roots, etc). Fir seedlings were strongly associated with woody mounds covered with thin mats of mixed mosses and Pleurozium shreberi (Bird.) Mitt. but negatively associated with flat topography particularly dominated by Hylocomium splendens (Hedw.) B.S.G. The presence of adventitious root is related to seedling age more than substrate type or topography. The age structure is in agreement with seed production and disturbance regime

Three siblings with Asperger syndrome: A family case study

Reports of multiple incidence of Asperger syndrome have suggested links between Asperger syndrome and autism. In this case study, we describe three siblings with Asperger syndrome based on the ICD-10 criteria. There was no family history of mental retardation or of autism. We propose that in some families, Asperger syndrome may occur as a distinct clinical entity and show no overlap with autism. Les publications sur l'incidence multiple du Syndrome d'Asperger ont suggéré des liens entre ce syndrome et l'autisme. Dans cette étude, nous décrivons 3 membres d'une même fratrie avec un Syndrome d'Asperger répondant aux critères d'l'ICD-10. Il n'yavait pas dans l'histoire familiale de retard mental ni d'autisme. Nous proposons que dans certaines familles le Syndrome d'Asperger peut survenir comme entité clinique distincte sand chevauchement avec l'autisme. Berichte über multiples Auftreten des Asperger-Syndroms haben Zusammenhänge zwischen dem Asperger-Syndrom und Autismus nahegelegt. In diesem Fallbericht beschreiben wir drei Geschwister mit einem Asperger-Syndrom (ICD-10-Kriterien). Die Familienanamnese im Hinblick auf geistige Behinderung oder Autismus war unauffällig. Wir schlagen vor, daß in einigen Familien das Asperger-Syndrom als eine eigenständige klinische Entität ohne Überlappung zum Autismus auftreten kann.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41755/1/787_2005_Article_BF02098829.pd

Intraspecific comparison of California sea lion (Zalophus californianus) diet assessed using fecal and stable isotope analyses

The diet of juvenile and adult female California sea lions (Zalophus californianus (Lesson, 1828)) at San Miguel Island, California, was estimated and compared using fecal and stable isotope analyses to determine dietary differences by age. Fecal samples were collected during 2002-2006 and prey hard parts were identified. Stable carbon (d13C) and nitrogen (d15N) isotope values were determined from plasma and fur obtained from yearlings, 2- to 3-yr old juveniles, and adult females during 2005 and 2006. Juveniles ate more than 15 prey taxa, whereas adult females consumed more than 33 prey taxa. Relative importance of prey was determined using percent requency of occurrence (%FO). Engraulis mordax (Girard, 1854), Sardinops sagax Jenyns, 1842), Merluccius productus (Ayres, 1855), Sebastes spp. (Cuvier, 1829), and Loligo opalescens (Berry, 1911) were the most frequently occurring (%FO &gt; 10%) prey in the fecal samples of both juvenile and adult female sea lions, although their mportance varied between age groups. Only yearlings had significantly different isotopic values than older conspecifics, indicating that older juveniles were feeding at a similar trophic level, and in similar habitats, as adult females. Whereas each method had biases and uncertainties, combining the two methods provided a better understanding of the diet of California sea lions and intraspecific differences

Identification of Significant Association and Gene-Gene Interaction of GABA Receptor Subunit Genes in Autism

Autism is a common neurodevelopmental disorder with a significant genetic component. Existing research suggests that multiple genes contribute to autism and that epigenetic effects or gene-gene interactions are likely contributors to autism risk. However, these effects have not yet been identified. Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, has been implicated in autism etiology. Fourteen known autosomal GABA receptor subunit genes were studied to look for the genes associated with autism and their possible interactions. Single-nucleotide polymorphisms (SNPs) were screened in the following genes: GABRG1, GABRA2,GABRA4, and GABRB1 on chromosome 4p12; GABRB2, GABRA6, GABRA1, GABRG2, and GABRP on 5q34-q35.1; GABRR1 and GABRR2 on 6q15; and GABRA5, GABRB3, and GABRG3 on 15q12. Intronic and/or silent mutation SNPs within each gene were analyzed in 470 white families with autism. Initially, SNPs were used in a family-based study for allelic association analysis—with the pedigree disequilibrium test and the family-based association test—and for genotypic and haplotypic association analysis—with the genotype-pedigree disequilibrium test (geno-PDT), the association in the presence of linkage (APL) test, and the haplotype family-based association test. Next, with the use of five refined independent marker sets, extended multifactor-dimensionality reduction (EMDR) analysis was employed to identify the models with locus joint effects, and interaction was further verified by conditional logistic regression. Significant allelic association was found for markers RS1912960 (in GABRA4; P = .01) and HCV9866022 (in GABRR2; P = .04). The geno-PDT found significant genotypic association for HCV8262334 (in GABRA2), RS1912960 and RS2280073 (in GABRA4), and RS2617503 and RS12187676 (in GABRB2). Consistent with the allelic and genotypic association results, EMDR confirmed the main effect at RS1912960 (in GABRA4). EMDR also identified a significant two-locus gene-gene effect model involving RS1912960 in GABRA4 and RS2351299 in GABRB1. Further support for this two-locus model came from both the multilocus geno-PDT and the APL test, which indicated a common genotype and haplotype combination positively associated with disease. Finally, these results were also consistent with the results from the conditional logistic regression, which confirmed the interaction between GABRA4 and GABRB1 (odds ratio = 2.9 for interaction term; P = .002). Through the convergence of all analyses, we conclude that GABRA4 is involved in the etiology of autism and potentially increases autism risk through interaction with GABRB1. These results support the hypothesis that GABA receptor subunit genes are involved in autism, most likely via complex gene-gene interactions

Fine Mapping of Autistic Disorder to Chromosome 15q11-q13 by Use of Phenotypic Subtypes

Autistic disorder (AutD) is a complex genetic disease. Available evidence suggests that several genes contribute to the underlying genetic risk for the development of AutD. However, both etiologic heterogeneity and genetic heterogeneity confound the discovery of AutD-susceptibility genes. Chromosome 15q11-q13 has been identified as a strong candidate region on the basis of both the frequent occurrence of chromosomal abnormalities in that region and numerous suggestive linkage and association findings. Ordered-subset analysis (OSA) is a novel statistical method to identify a homogeneous subset of families that contribute to overall linkage at a given chromosomal location and thus to potentially help in the fine mapping and localization of the susceptibility gene within a chromosomal area. For the present analysis, a factor that represents insistence on sameness (IS)—derived from a principal-component factor analysis using data on 221 patients with AutD from the repetitive behaviors/stereotyped patterns domain in the Autism Diagnostic Interview–Revised—was used as a covariate in OSA. Analysis of families sharing high scores on the IS factor increased linkage evidence for the 15q11-q13 region, at the GABRB3 locus, from a LOD score of 1.45 to a LOD score of 4.71. These results narrow our region of interest on chromosome 15 to an area surrounding the γ-aminobutyric acid–receptor subunit genes, in AutD, and support the hypothesis that the analysis of phenotypic homogeneous subtypes may be a powerful tool for the mapping of disease-susceptibility genes in complex traits

Genetic Studies of Autistic Disorder and Chromosome 7

Genome-wide scans have suggested that a locus on 7q is involved in the etiology of autistic disorder (AD). We have identified an AD family in which three sibs inherited from their mother a paracentric inversion in the chromosome 7 candidate region (inv(7)(q22–q31.2)). Clinically, the two male sibs have AD, while the female sib has expressive language disorder. The mother carries the inversion, but does not express AD. Haplotype data on the family suggest that the chromosomal origin of the inversion was from the children's maternal grandfather. Based on these data, we have genotyped 76 multiplex (≥2 AD affecteds/family) families for markers in this region of 7q. Two-point linkage analysis yielded a maximum heterogeneity lod score of 1.47 and maximum lod score (MLS) of 1.03 at D7S495. Multipoint MLS and NPL analyses resulted in peak scores of 1.77 at D7S2527 and 2.01 at D7S640. Examination of affected sibpairs revealed significant paternal (P = 0.007), but not maternal (P = 0.75), identity-by-descent sharing at D7S640. Significant linkage disequilibrium was detected with paternal (P = 0.02), but not maternal (P = 0.15), transmissions at D7S1824 in multiplex and singleton families. There was also evidence for an increase in recombination in the region (D7S1817 to D7S1824) in the AD families versus non-AD families (P = 0.03, sex-averaged; and P = 0.01, sex-specific). These results provide further evidence for the presence of an AD locus on chromosome 7q, as well as provide evidence suggesting that this locus may be paternally expressed

Dissimilarity-Based Classification of Anatomical Tree Structures

Abstract. A novel method for classification of abnormality in anatomical tree structures is presented. A tree is classified based on direct comparisons with other trees in a dissimilarity-based classification scheme. The pair-wise dissimilarity measure between two trees is based on a linear assignment between the branch feature vectors representing those trees. Hereby, localized information in the branches is collectively used in classification and variations in feature values across the tree are taken into account. An approximate anatomical correspondence between matched branches can be achieved by including anatomical features in the branch feature vectors. The proposed approach is applied to classify airway trees in computed tomography images of subjects with and without chronic obstructive pulmonary disease (COPD). Using the wall area percentage (WA%), a common measure of airway abnormality in COPD, as well as anatomical features to characterize each branch, an area under the receiver operating characteristic curve of 0.912 is achieved. This is significantly better than computing the average WA%