972 research outputs found
LATE for the meeting: Gender, peer advising, and college success
Many male and first-generation college-goers struggle in their first year of postsecondary education. Mentoring programs have been touted as a potential solution to help such students acclimate to college life, yet causal evidence on the impact of such programs, and the factors that influence participation in them, is scant. This study leverages a natural experiment in which peer advisors (PAs) were quasi-randomly assigned to first-year university students to show that 1) male students were significantly more likely to voluntarily meet with their assigned PA when the PA was also male and 2) these compliers were significantly more likely to persist into the second year of postsecondary schooling. We find no effect of being assigned to a same-sex PA on female students’ use of the PA program, nor do we find any evidence that the PA program affected subsequent academic performance (GPAs)
LATE for the Meeting: Gender, Peer Advising, and College Success
Many male and first-generation college-goers struggle in their first year of postsecondary education. Mentoring programs have been touted as a potential solution to help such students acclimate to college life, yet causal evidence on the impact of such programs, and the factors that influence participation in them, is scant. This study leverages a natural experiment in which peer advisors (PAs) were quasi-randomly assigned to first-year university students to show that 1) male students were significantly more likely to voluntarily meet with their assigned PA when the PA was also male and 2) these compliers were significantly more likely to persist into the second year of postsecondary schooling. We find no effect of being assigned to a same-sex PA on female students’ use of the PA program, nor do we find any evidence that the PA program affected subsequent academic performance (GPAs)
Resolving Small Business Disputes Through Mediation
A revolution is taking place in the way Americans resolve their disputes. The so-called alternative methods of dispute resolution such as mediation and arbitration are increasingly becoming a primary choice for settling conflict. A growing number of large American companies have begun to embrace mediation as an alternative to litigation. The article describes the mediation process in the small business context. The advantages and disadvantages of mediation versus the judicial process are considered. Recommendations concerning the appropriate circumstances in which small business should use mediation to resolve conflict are provided. Also reported are the results of a survey of small business executives that measured their attitudes toward mediation and other forms of dispute resolution. The results suggest that most executives preferred mediation to other forms of dispute resolution. They believe mediation to be a cost-effective and efficient method of resolving conflicts with customers, employees, and suppliers
Jet-veto resummation at NLL+NNLO in boson production processes
Vetoing energetic jet activity is a crucial tool for suppressing backgrounds
and enabling new physics searches at the LHC, but the introduction of a veto
scale can introduce large logarithms that may need to be resummed. We present
an implementation of jet-veto resummation for color-singlet processes at the
level of NLL matched to fixed-order NNLO predictions. Our public
code MCFM allows for predictions of a single boson, such as ,
or , or with a pair of vector bosons, such as , or . The implementation relies on recent calculations of the soft and
beam functions in the presence of a jet veto over all rapidities, with jets
defined using a sequential recombination algorithm with jet radius . However
one of the ingredients that is required to reach full NLL accuracy is only
known approximately, hence NLL. We describe in detail our
formalism and compare with previous public codes that operate at the level of
NNLL. Our higher-order predictions improve significantly upon NNLL calculations
by reducing theoretical uncertainties. We demonstrate this by comparing our
predictions with ATLAS and CMS results.Comment: 58 pages, 19 Figures, published version with additional figures
(Fig.13 and Fig.18(b)) assessing uncertainty caused by the unknown d_3^veto.
Improvement of language on logarithmic order of initial gluon contributions
and comparison with JetVHeto. Recalculation of resummed uncertainties, giving
minor updates to figures throughout. Qualitative conclusions are unchange
Constraints on Low-Mass WIMP Interactions on 19F from PICASSO
Recent results from the PICASSO dark matter search experiment at SNOLAB are
reported. These results were obtained using a subset of 10 detectors with a
total target mass of 0.72 kg of 19F and an exposure of 114 kgd. The low
backgrounds in PICASSO allow recoil energy thresholds as low as 1.7 keV to be
obtained which results in an increased sensitivity to interactions from Weakly
Interacting Massive Particles (WIMPs) with masses below 10 GeV/c^2. No dark
matter signal was found. Best exclusion limits in the spin dependent sector
were obtained for WIMP masses of 20 GeV/c^2 with a cross section on protons of
sigma_p^SD = 0.032 pb (90% C.L.). In the spin independent sector close to the
low mass region of 7 GeV/c2 favoured by CoGeNT and DAMA/LIBRA, cross sections
larger than sigma_p^SI = 1.41x10^-4 pb (90% C.L.) are excluded.Comment: 23 pages, 7 figures, to be published in Phys. Lett.
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
A review of elliptical and disc galaxy structure, and modern scaling laws
A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their
models to describe the radial distribution of stars in `nebulae'. This article
reviews the progress since then, providing both an historical perspective and a
contemporary review of the stellar structure of bulges, discs and elliptical
galaxies. The quantification of galaxy nuclei, such as central mass deficits
and excess nuclear light, plus the structure of dark matter halos and cD galaxy
envelopes, are discussed. Issues pertaining to spiral galaxies including dust,
bulge-to-disc ratios, bulgeless galaxies, bars and the identification of
pseudobulges are also reviewed. An array of modern scaling relations involving
sizes, luminosities, surface brightnesses and stellar concentrations are
presented, many of which are shown to be curved. These 'redshift zero'
relations not only quantify the behavior and nature of galaxies in the Universe
today, but are the modern benchmark for evolutionary studies of galaxies,
whether based on observations, N-body-simulations or semi-analytical modelling.
For example, it is shown that some of the recently discovered compact
elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to
appear in "Planets, Stars and Stellar
Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references
incl. many somewhat forgotten, pioneer papers. Original submission to
Springer: 07-June-201
Enhanced Fusion Pore Expansion Mediated by the Trans-Acting Endodomain of the Reovirus FAST Proteins
The reovirus fusion-associated small transmembrane (FAST) proteins are virus-encoded membrane fusion proteins that function as dedicated cell–cell fusogens. The topology of these small, single-pass membrane proteins orients the majority of the protein on the distal side of the membrane (i.e., inside the cell). We now show that ectopic expression of the endodomains of the p10, p14, and p15 FAST proteins enhances syncytiogenesis induced by the full-length FAST proteins, both homotypically and heterotypically. Results further indicate that the 68-residue cytoplasmic endodomain of the p14 FAST protein (1) is endogenously generated from full-length p14 protein expressed in virus-infected or transfected cells; (2) enhances syncytiogenesis subsequent to stable pore formation; (3) increases the syncytiogenic activity of heterologous fusion proteins, including the differentiation-dependent fusion of murine myoblasts; (4) exerts its enhancing activity from the cytosol, independent of direct interactions with either the fusogen or the membranes being fused; and (5) contains several regions with protein–protein interaction motifs that influence enhancing activity. We propose that the unique evolution of the FAST proteins as virus-encoded cellular fusogens has allowed them to generate a trans-acting, soluble endodomain peptide to harness a cellular pathway or process involved in the poorly understood process that facilitates the transition from microfusion pores to macrofusion and syncytiogenesis
Revealing the Functions of the Transketolase Enzyme Isoforms in Rhodopseudomonas palustris Using a Systems Biology Approach
BACKGROUND: Rhodopseudomonas palustris (R. palustris) is a purple non-sulfur anoxygenic phototrophic bacterium that belongs to the class of proteobacteria. It is capable of absorbing atmospheric carbon dioxide and converting it to biomass via the process of photosynthesis and the Calvin-Benson-Bassham (CBB) cycle. Transketolase is a key enzyme involved in the CBB cycle. Here, we reveal the functions of transketolase isoforms I and II in R. palustris using a systems biology approach. METHODOLOGY/PRINCIPAL FINDINGS: By measuring growth ability, we found that transketolase could enhance the autotrophic growth and biomass production of R. palustris. Microarray and real-time quantitative PCR revealed that transketolase isoforms I and II were involved in different carbon metabolic pathways. In addition, immunogold staining demonstrated that the two transketolase isoforms had different spatial localizations: transketolase I was primarily associated with the intracytoplasmic membrane (ICM) but transketolase II was mostly distributed in the cytoplasm. Comparative proteomic analysis and network construction of transketolase over-expression and negative control (NC) strains revealed that protein folding, transcriptional regulation, amino acid transport and CBB cycle-associated carbon metabolism were enriched in the transketolase I over-expressed strain. In contrast, ATP synthesis, carbohydrate transport, glycolysis-associated carbon metabolism and CBB cycle-associated carbon metabolism were enriched in the transketolase II over-expressed strain. Furthermore, ATP synthesis assays showed a significant increase in ATP synthesis in the transketolase II over-expressed strain. A PEPCK activity assay showed that PEPCK activity was higher in transketolase over-expressed strains than in the negative control strain. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that the two isoforms of transketolase in R. palustris could affect photoautotrophic growth through both common and divergent metabolic mechanisms
Ensemble Decision Tree Models Using RUSBoost for Estimating Risk of Iron Failure in Drinking Water Distribution Systems
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