49 research outputs found
Essential elements of treatment: a comparative study between European and American therapeutic communities for addiction
The purpose of this study was to investigate whether European and American therapeutic communities (TCs) for addiction, both traditional and modified, share a common perspective on what is essential in treatment using the Survey of Essential Elements Questionnaire (SEEQ). The European sample (N = 19) was gathered in 2009. For the American sample (N = 19) we used previously published research data. Despite comparable perspectives, European traditional TCs (N = 11) scored significantly higher than their American predecessors (N = 11) on 4 SEEQ domains. Cluster differences were more pronounced in Europe than in America
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Characterization of a large sex determination region in Salix purpurea L. (Salicaceae).
Dioecy has evolved numerous times in plants, but heteromorphic sex chromosomes are apparently rare. Sex determination has been studied in multiple Salix and Populus (Salicaceae) species, and P. trichocarpa has an XY sex determination system on chromosome 19, while S. suchowensis and S. viminalis have a ZW system on chromosome 15. Here we use whole genome sequencing coupled with quantitative trait locus mapping and a genome-wide association study to characterize the genomic composition of the non-recombining portion of the sex determination region. We demonstrate that Salix purpurea also has a ZW system on chromosome 15. The sex determination region has reduced recombination, high structural polymorphism, an abundance of transposable elements, and contains genes that are involved in sex expression in other plants. We also show that chromosome 19 contains sex-associated markers in this S. purpurea assembly, along with other autosomes. This raises the intriguing possibility of a translocation of the sex determination region within the Salicaceae lineage, suggesting a common evolutionary origin of the Populus and Salix sex determination loci
Physiological modeling of isoprene dynamics in exhaled breath
Human breath contains a myriad of endogenous volatile organic compounds
(VOCs) which are reflective of ongoing metabolic or physiological processes.
While research into the diagnostic potential and general medical relevance of
these trace gases is conducted on a considerable scale, little focus has been
given so far to a sound analysis of the quantitative relationships between
breath levels and the underlying systemic concentrations. This paper is devoted
to a thorough modeling study of the end-tidal breath dynamics associated with
isoprene, which serves as a paradigmatic example for the class of low-soluble,
blood-borne VOCs.
Real-time measurements of exhaled breath under an ergometer challenge reveal
characteristic changes of isoprene output in response to variations in
ventilation and perfusion. Here, a valid compartmental description of these
profiles is developed. By comparison with experimental data it is inferred that
the major part of breath isoprene variability during exercise conditions can be
attributed to an increased fractional perfusion of potential storage and
production sites, leading to higher levels of mixed venous blood concentrations
at the onset of physical activity. In this context, various lines of supportive
evidence for an extrahepatic tissue source of isoprene are presented.
Our model is a first step towards new guidelines for the breath gas analysis
of isoprene and is expected to aid further investigations regarding the
exhalation, storage, transport and biotransformation processes associated with
this important compound.Comment: 14 page
Genome resequencing reveals multiscale geographic structure and extensive linkage disequilibrium in the forest tree Populus trichocarpa
This is the publisher’s final pdf. The article is copyrighted by the New Phytologist Trust and published by John Wiley & Sons, Inc. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291469-8137. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work.•Plant population genomics informs evolutionary biology, breeding, conservation and bioenergy feedstock development. For example, the detection of reliable phenotype–genotype associations and molecular signatures of selection requires a detailed knowledge about genome-wide patterns of allele frequency variation, linkage disequilibrium and recombination.\ud
•We resequenced 16 genomes of the model tree Populus trichocarpa and genotyped 120 trees from 10 subpopulations using 29 213 single-nucleotide polymorphisms.\ud
•Significant geographic differentiation was present at multiple spatial scales, and range-wide latitudinal allele frequency gradients were strikingly common across the genome. The decay of linkage disequilibrium with physical distance was slower than expected from previous studies in Populus, with r² dropping below 0.2 within 3–6 kb. Consistent with this, estimates of recent effective population size from linkage disequilibrium (N[subscript e] ≈ 4000–6000) were remarkably low relative to the large census sizes of P. trichocarpa stands. Fine-scale rates of recombination varied widely across the genome, but were largely predictable on the basis of DNA sequence and methylation features.\ud
•Our results suggest that genetic drift has played a significant role in the recent evolutionary history of P. trichocarpa. Most importantly, the extensive linkage disequilibrium detected suggests that genome-wide association studies and genomic selection in undomesticated populations may be more feasible in Populus than previously assumed
The Scientific Investigation of Unidentified Aerial Phenomena (UAP) Using Multimodal Ground-based Observatories
Peer reviewedPublisher PD
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Genome resequencing reveals multiscale geographic structure and extensive linkage disequilibrium in the forest tree Populus trichocarpa
•Plant population genomics informs evolutionary biology, breeding, conservation and bioenergy feedstock development. For example, the detection of reliable phenotype–genotype associations and molecular signatures of selection requires a detailed knowledge about genome-wide patterns of allele frequency variation, linkage disequilibrium and recombination.
•We resequenced 16 genomes of the model tree Populus trichocarpa and genotyped 120 trees from 10 subpopulations using 29 213 single-nucleotide polymorphisms.
•Significant geographic differentiation was present at multiple spatial scales, and range-wide latitudinal allele frequency gradients were strikingly common across the genome. The decay of linkage disequilibrium with physical distance was slower than expected from previous studies in Populus, with r² dropping below 0.2 within 3–6 kb. Consistent with this, estimates of recent effective population size from linkage disequilibrium (N[subscript e] ≈ 4000–6000) were remarkably low relative to the large census sizes of P. trichocarpa stands. Fine-scale rates of recombination varied widely across the genome, but were largely predictable on the basis of DNA sequence and methylation features.
•Our results suggest that genetic drift has played a significant role in the recent evolutionary history of P. trichocarpa. Most importantly, the extensive linkage disequilibrium detected suggests that genome-wide association studies and genomic selection in undomesticated populations may be more feasible in Populus than previously assumed.This is the publisher’s final pdf. The article is copyrighted by the New Phytologist Trust and published by John Wiley & Sons, Inc. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291469-8137Keywords: recombination., allele frequency gradients, linkage disequilibrium (LD), population structure, black cottonwood (Populus trichocarpa), genome resequencin