160 research outputs found
Overlapping resonances in the control of intramolecular vibrational redistribution
Coherent control of bound state processes via the interfering overlapping
resonances scenario [Christopher et al., J. Chem. Phys. 123, 064313 (2006)] is
developed to control intramolecular vibrational redistribution (IVR). The
approach is applied to the flow of population between bonds in a model of
chaotic OCS vibrational dynamics, showing the ability to significantly alter
the extent and rate of IVR by varying quantum interference contributions.Comment: 10 pages, 7 figure
The role of sociopolitical workplace networks in involuntary employee turnover
While poor performance is one reason employees are fired, previous research suggests it plays a limited role in explaining terminations. We argue that sociopolitical concerns play a role in determining who is terminated. Using field data from a U.S. health care company and experimental data using participants with supervisory experience, we show how the supervisorβs political concerns with the focal employee, which are contingent on the supervisor-employee political relationship and the way it is embedded within the workplace network, are related to dismissal decisions. Not only do we expect that a supervisor will be less likely to terminate an employee they see as a political ally and more likely to dismiss an adversary, but we also argue that a supervisor with fewer (more) alternative allies to the employee is less (more) likely to dismiss the employee. Additionally, a supervisor with numerous adversaries in their own network depends more heavily on the employee politically, making dismissal less likely, whereas if the employee has numerous adversaries, the supervisor has greater latitude to terminate the employee. Our findings contribute to research on involuntary turnover by showing that a social network approach to understanding organizational politics helps us understand why specific individuals are targeted for dismissal, above and beyond performance considerations
The Lyman Continuum escape fraction of galaxies at z=3.3 in the VUDS-LBC/COSMOS field
The Lyman continuum (LyC) flux escaping from high-z galaxies into the IGM is
a fundamental quantity to understand the physical processes involved in the
reionization epoch. We have investigated a sample of star-forming galaxies at
z~3.3 in order to search for possible detections of LyC photons escaping from
galaxy halos. UV deep imaging in the COSMOS field obtained with the prime focus
camera LBC at the LBT telescope was used together with a catalog of
spectroscopic redshifts obtained by the VIMOS Ultra Deep Survey (VUDS) to build
a sample of 45 galaxies at z~3.3 with L>0.5L*. We obtained deep LBC images of
galaxies with spectroscopic redshifts in the interval 3.27<z<3.40 both in the R
and deep U bands. A sub-sample of 10 galaxies apparently shows escape
fractions>28% but a detailed analysis of their properties reveals that, with
the exception of two marginal detections (S/N~2) in the U band, all the other 8
galaxies are most likely contaminated by the UV flux of low-z interlopers
located close to the high-z targets. The average escape fraction derived from
the stacking of the cleaned sample was constrained to fesc_rel<2%. The implied
HI photo-ionization rate is a factor two lower than that needed to keep the IGM
ionized at z~3, as observed in the Lyman forest of high-z QSO spectra or by the
proximity effect. These results support a scenario where high redshift,
relatively bright (L>0.5L*) star-forming galaxies alone are unable to sustain
the level of ionization observed in the cosmic IGM at z~3. Star-forming
galaxies at higher redshift and at fainter luminosities (L<<L*) can be the
major contributors to the reionization of the Universe only if their physical
properties are subject to rapid changes from z~3 to z~6-10. Alternatively,
ionizing sources could be discovered looking for fainter sources among the AGN
population at high-z.Comment: 21 pages, 9 figures. Accepted for publication in A&
Comparative genomic analysis of Leishmania (Viannia) peruviana and Leishmania (Viannia) braziliensis
BACKGROUND: The Leishmania (Viannia) braziliensis complex is responsible for most cases of New World tegumentary leishmaniasis. This complex includes two closely related species but with different geographic distribution and disease phenotypes, L. (V.) peruviana and L. (V.) braziliensis. However, the genetic basis of these differences is not well understood and the status of L. (V.) peruviana as distinct species has been questioned by some. Here we sequenced the genomes of two L. (V.) peruviana isolates (LEM1537 and PAB-4377) using Illumina high throughput sequencing and performed comparative analyses against the L. (V.) braziliensis M2904 reference genome. Comparisons were focused on the detection of Single Nucleotide Polymorphisms (SNPs), insertions and deletions (INDELs), aneuploidy and gene copy number variations. RESULTS: We found 94,070 variants shared by both L. (V.) peruviana isolates (144,079 in PAB-4377 and 136,946 in LEM1537) against the L. (V.) braziliensis M2904 reference genome while only 26,853 variants separated both L. (V.) peruviana genomes. Analysis in coding sequences detected 26,750 SNPs and 1,513 indels shared by both L. (V.) peruviana isolates against L. (V.) braziliensis M2904 and revealed two L. (V.) braziliensis pseudogenes that are likely to have coding potential in L. (V.) peruviana. Chromosomal read density and allele frequency profiling showed a heterogeneous pattern of aneuploidy with an overall disomic tendency in both L. (V.) peruviana isolates, in contrast with a trisomic pattern in the L. (V.) braziliensis M2904 reference. Read depth analysis allowed us to detect more than 368 gene expansions and 14 expanded gene arrays in L. (V.) peruviana, and the likely absence of expanded amastin gene arrays. CONCLUSIONS: The greater numbers of interspecific SNP/indel differences between L. (V.) peruviana and L. (V.) braziliensis and the presence of different gene and chromosome copy number variations support the classification of both organisms as closely related but distinct species. The extensive nucleotide polymorphisms and differences in gene and chromosome copy numbers in L. (V.) peruviana suggests the possibility that these may contribute to some of the unique features of its biology, including a lower pathology and lack of mucosal development. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1928-z) contains supplementary material, which is available to authorized users
Selective Whole-Genome Amplification Is a Robust Method That Enables Scalable Whole-Genome Sequencing of Plasmodium vivax from Unprocessed Clinical Samples.
Whole-genome sequencing (WGS) of microbial pathogens from clinical samples is a highly sensitive tool used to gain a deeper understanding of the biology, epidemiology, and drug resistance mechanisms of many infections. However, WGS of organisms which exhibit low densities in their hosts is challenging due to high levels of host genomic DNA (gDNA), which leads to very low coverage of the microbial genome. WGS of Plasmodium vivax, the most widely distributed form of malaria, is especially difficult because of low parasite densities and the lack of an ex vivo culture system. Current techniques used to enrich P.Β vivax DNA from clinical samples require significant resources or are not consistently effective. Here, we demonstrate that selective whole-genome amplification (SWGA) can enrich P.Β vivax gDNA from unprocessed human blood samples and dried blood spots for high-quality WGS, allowing genetic characterization of isolates that would otherwise have been prohibitively expensive or impossible to sequence. We achieved an average genome coverage of 24Γ, with up to 95% of the P.Β vivax core genome covered by β₯5 reads. The single-nucleotide polymorphism (SNP) characteristics and drug resistance mutations seen were consistent with those of other P.Β vivax sequences from a similar region in Peru, demonstrating that SWGA produces high-quality sequences for downstream analysis. SWGA is a robust tool that will enable efficient, cost-effective WGS of P.Β vivax isolates from clinical samples that can be applied to other neglected microbial pathogens. IMPORTANCE: Malaria is a disease caused by Plasmodium parasites that caused 214 million symptomatic cases and 438,000 deaths in 2015. Plasmodium vivax is the most widely distributed species, causing the majority of malaria infections outside sub-Saharan Africa. Whole-genome sequencing (WGS) of Plasmodium parasites from clinical samples has revealed important insights into the epidemiology and mechanisms of drug resistance of malaria. However, WGS of P.Β vivax is challenging due to low parasite levels in humans and the lack of a routine system to culture the parasites. Selective whole-genome amplification (SWGA) preferentially amplifies the genomes of pathogens from mixtures of target and host gDNA. Here, we demonstrate that SWGA is a simple, robust method that can be used to enrich P.Β vivax genomic DNA (gDNA) from unprocessed human blood samples and dried blood spots for cost-effective, high-quality WGS
Defendant characteristics and judgment behaviors of adolescent mock jurors
Fictitious court cases involving child abuse were presented to 140 male undergraduates and 140 male junior high school students to determine if the tendency to deal harshly with alleged criminals is dependent upon certain defendant characteristics. Results indicate that younger adolescent jurors give longer sentences than older adolescent jurors, and male defendants receive longer sentences than female defendants. While no significant main effects for case content were found, younger jurors gave longer sentences and attributed more responsibility to a parent who beat his/her child, while older adolescent jurors attributed more responsibility and prescribed longer sentences to a parent who burned the child. Implications for future research with adolescent jurors are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45262/1/10964_2005_Article_BF02089106.pd
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Mental health training for secondary school teachers in Haiti: a mixed methods, prospective, formative research study of feasibility, acceptability, and effectiveness in knowledge acquisition
Background: Engagement and training of educators in student mental health holds promise for promoting access to care as a task sharing strategy but has not been well-studied in low-income regions. Methods: We used a prospective and convergent mixed methods design to evaluate a customized school mental health 2Β½ day training for teachers in rural Haiti (n = 22) as the initial component of formative research developing a school-based intervention to promote student mental health. Training prepared teachers to respond to student mental health needs by providing psychoeducational and practical support to facilitate access to care. We examined level of participation and evaluated feasibility, acceptability, and perceived effectiveness by calculating mean scores on self-report Likert-style items eliciting participant experience. We examined effectiveness of the training on improving mental health knowledge and attitudes by comparing mean scores on an assessment administered pre- and post-training. Finally, we examined self-report written open-ended responses and focus group discussion (FGD) interview data bearing on perceived feasibility, acceptability, and effectiveness to contextualize participant ratings of training and to identify recommendations for enhancing the utility of mental health training locally for educators. Results: Mean scores of knowledge and attitudes significantly improved between the pre-test and post-tests; e.g., knowledge improved from 58% correct at baseline to 68% correct on the second post-test (p = 0.039). Mean ratings of the training were favorable across all categories and FGD data demonstrated widespread participant endorsement of training acceptability and effectiveness; participants recommended extending the duration and number of training sessions. Conclusions: Findings support feasibility, acceptability, and a limited scope of effectiveness of brief mental health training for secondary school teachers in Haiti. Further development of approaches to engage teachers in promoting school mental health through training is warranted
Asc1 Supports Cell-Wall Integrity Near Bud Sites by a Pkc1 Independent Mechanism
Background: The yeast ribosomal protein Asc1 is a WD-protein family member. Its mammalian ortholog, RACK1 was initially discovered as a receptor for activated protein C kinase (PKC) that functions to maintain the active conformation of PKC and to support its movement to target sites. In the budding yeast though, a connection between Asc1p and the PKC signaling pathway has never been reported. Methodology/Principal Findings: In the present study we found that asc1-deletion mutant (asc1D) presents some of the hallmarks of PKC signaling mutants. These include an increased sensitivity to staurosporine, a specific Pkc1p inhibitor, and susceptibility to cell-wall perturbing treatments such as hypotonic- and heat shock conditions and zymolase treatment. Microscopic analysis of asc1D cells revealed cell-wall invaginations near bud sites after exposure to hypotonic conditions, and the dynamic of cells β survival after this stress further supports the involvement of Asc1p in maintaining the cell-wall integrity during the mid-to late stages of bud formation. Genetic interactions between asc1 and pkc1 reveal synergistic sensitivities of a double-knock out mutant (asc1D/pkc1D) to cell-wall stress conditions, and high basal level of PKC signaling in asc1D. Furthermore, Asc1p has no effect on the cellular distribution or redistribution of Pkc1p at optimal or at cell-wall stress conditions. Conclusions/Significance: Taken together, our data support the idea that unlike its mammalian orthologs, Asc1p act
Trypanosomatid RACK1 Orthologs Show Functional Differences Associated with Translation Despite Similar Roles in Leishmania Pathogenesis
RACK1 proteins belong to the eukaryote WD40-repeat protein family and function as spatial regulators of multiple cellular events, including signaling pathways, the cell cycle and translation. For this latter role, structural and genetic studies indicate that RACK1 associates with the ribosome through two conserved positively charged amino acids in its first WD40 domain. Unlike RACK1s, including Trypanosoma brucei RACK1 (TbRACK1), only one of these two positively-charged residues is conserved in the first WD40 domain of the Leishmania major RACK1 ortholog, LACK. We compared virulence-attenuated LACK single copy (LACK/-) L. major, with L. major expressing either two LACK copies (LACK/LACK), or one copy each of LACK and TbRACK1 (LACK/TbRACK1), to evaluate the function of these structurally distinct RACK1 orthologs with respect to translation, viability at host temperatures and pathogenesis. Our results indicate that although the ribosome-binding residues are not fully conserved in LACK, both LACK and TbRACK1 co-sedimented with monosomes and polysomes in LACK/LACK and LACK/TbRACK1 L. major, respectively. LACK/LACK and LACK/TbRACK1 strains differed in their sensitivity to translation inhibitors implying that minor sequence differences between the RACK1 proteins can alter their functional properties. While biochemically distinguishable, both LACK/LACK and LACK/TbRACK1 lines were more tolerant of elevated temperatures, resistant to translation inhibitors, and displayed robust pathogenesis in vivo, contrasting to LACK/- parasites
Rational Extension of the Ribosome Biogenesis Pathway Using Network-Guided Genetics
Gene networks are an efficient route for associating candidate genes with biological processes. Here, networks are used to discover more than 15 new genes for ribosomal subunit maturation, rRNA processing, and ribosomal export from the nucleus
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