3,407 research outputs found
Jet Observables Without Jet Algorithms
We introduce a new class of event shapes to characterize the jet-like
structure of an event. Like traditional event shapes, our observables are
infrared/collinear safe and involve a sum over all hadrons in an event, but
like a jet clustering algorithm, they incorporate a jet radius parameter and a
transverse momentum cut. Three of the ubiquitous jet-based observables---jet
multiplicity, summed scalar transverse momentum, and missing transverse
momentum---have event shape counterparts that are closely correlated with their
jet-based cousins. Due to their "local" computational structure, these jet-like
event shapes could potentially be used for trigger-level event selection at the
LHC. Intriguingly, the jet multiplicity event shape typically takes on
non-integer values, highlighting the inherent ambiguity in defining jets. By
inverting jet multiplicity, we show how to characterize the transverse momentum
of the n-th hardest jet without actually finding the constituents of that jet.
Since many physics applications do require knowledge about the jet
constituents, we also build a hybrid event shape that incorporates (local) jet
clustering information. As a straightforward application of our general
technique, we derive an event-shape version of jet trimming, allowing
event-wide jet grooming without explicit jet identification. Finally, we
briefly mention possible applications of our method for jet substructure
studies.Comment: v2 - 31 pages, 18 figures; update to JHEP version, section 3.2
expanded, reference to FastJet contrib updated, results unchange
Lateral Shift Makes a Ground-Plane Cloak Detectable
We examine the effectiveness of the ground-plane invisibility cloak generated
from quasiconformal mapping of electromagnetic space. This cloak without
anisotropy will generally lead to a lateral shift of the scattered wave, whose
value is comparable to the height of the cloaked object, making the object
detectable. This can be explained by the fact that the corresponding virtual
space is thinner and wider than it should be. Ray tracing on a concrete model
shows that for a bump with a maximum height of 0.2 units to be hidden, the
lateral shift of a ray with 45 degree incidence is around 0.15 units
A computer-assisted motivational social network intervention to reduce alcohol, drug and HIV risk behaviors among Housing First residents.
BackgroundIndividuals transitioning from homelessness to housing face challenges to reducing alcohol, drug and HIV risk behaviors. To aid in this transition, this study developed and will test a computer-assisted intervention that delivers personalized social network feedback by an intervention facilitator trained in motivational interviewing (MI). The intervention goal is to enhance motivation to reduce high risk alcohol and other drug (AOD) use and reduce HIV risk behaviors.Methods/designIn this Stage 1b pilot trial, 60 individuals that are transitioning from homelessness to housing will be randomly assigned to the intervention or control condition. The intervention condition consists of four biweekly social network sessions conducted using MI. AOD use and HIV risk behaviors will be monitored prior to and immediately following the intervention and compared to control participants' behaviors to explore whether the intervention was associated with any systematic changes in AOD use or HIV risk behaviors.DiscussionSocial network health interventions are an innovative approach for reducing future AOD use and HIV risk problems, but little is known about their feasibility, acceptability, and efficacy. The current study develops and pilot-tests a computer-assisted intervention that incorporates social network visualizations and MI techniques to reduce high risk AOD use and HIV behaviors among the formerly homeless. CLINICALTRIALS.Gov identifierNCT02140359
The Transit Light Curve project. XIV. Confirmation of Anomalous Radii for the Exoplanets TrES-4b, HAT-P-3b, and WASP-12b
We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and
WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b
and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706 +/-
0.056 R_Jup and 1.736 +/- 0.092 R_Jup, respectively. These planets are too
large to be explained with standard models of gas giant planets. In contrast,
HAT-P-3b has a radius of 0.827 +/- 0.055 R_Jup, smaller than a pure
hydrogen-helium planet and indicative of a highly metal-enriched composition.
Analyses of the transit timings revealed no significant departures from strict
periodicity. For TrES-4, our relatively recent observations allow for
improvement in the orbital ephemerides, which is useful for planning future
observations.Comment: AJ, in press [11 pages]; corrected error in distance to WASP-1
Changing an Unfavorable Employer Reputation: The Roles of Recruitment Message-Type and Familiarity with Employer
An unfavorable employer reputation can impair an organization’s ability to recruit job seekers. The present research employed a four-week longitudinal experimental design to investigate whether recruitment messages can positively change an existing unfavorable employer reputation. Two hundred and twenty-two (222) job seekers rated their perceptions of an organization before and after being randomly assigned to receive a series of high- or low-information recruitment messages. As expected, job seekers receiving high-information messages changed their perceptions more than job seekers who were exposed to low-information messages. In addition, job seekers’ initial familiarity with the employer was negatively related to change in their perceptions of employer reputation. Finally, there was some evidence that job seekers’ familiarity with the employer influenced the impact of different recruitment messages. Implications for research and practice are discussed
How claim specificity can improve claim credibility in Green Advertising: Measures that can boost outcomes from environmental product claims
This study establishes claim specificity as a conceptually distinct message characteristic and a robust antecedent of claim credibility. The relationship between the specificity and the credibility of green claims is examined by way of a 2 Ă— 2 online experiment, with a broad sample of consumers. The results show that being specific increased the perceived credibility of green claims across a range of products, regardless of their perceived environmental relevance. Theoretical, practical, and research implications are discussed
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Succession of physiological stages hallmarks the transcriptomic response of the fungus Aspergillus niger to lignocellulose.
BackgroundUnderstanding how fungi degrade lignocellulose is a cornerstone of improving renewables-based biotechnology, in particular for the production of hydrolytic enzymes. Considerable progress has been made in investigating fungal degradation during time-points where CAZyme expression peaks. However, a robust understanding of the fungal survival strategies over its life time on lignocellulose is thereby missed. Here we aimed to uncover the physiological responses of the biotechnological workhorse and enzyme producer Aspergillus niger over its life time to six substrates important for biofuel production.ResultsWe analysed the response of A. niger to the feedstock Miscanthus and compared it with our previous study on wheat straw, alone or in combination with hydrothermal or ionic liquid feedstock pretreatments. Conserved (substrate-independent) metabolic responses as well as those affected by pretreatment and feedstock were identified via multivariate analysis of genome-wide transcriptomics combined with targeted transcript and protein analyses and mapping to a metabolic model. Initial exposure to all substrates increased fatty acid beta-oxidation and lipid metabolism transcripts. In a strain carrying a deletion of the ortholog of the Aspergillus nidulans fatty acid beta-oxidation transcriptional regulator farA, there was a reduction in expression of selected lignocellulose degradative CAZyme-encoding genes suggesting that beta-oxidation contributes to adaptation to lignocellulose. Mannan degradation expression was wheat straw feedstock-dependent and pectin degradation was higher on the untreated substrates. In the later life stages, known and novel secondary metabolite gene clusters were activated, which are of high interest due to their potential to synthesize bioactive compounds.ConclusionIn this study, which includes the first transcriptional response of Aspergilli to Miscanthus, we highlighted that life time as well as substrate composition and structure (via variations in pretreatment and feedstock) influence the fungal responses to lignocellulose. We also demonstrated that the fungal response contains physiological stages that are conserved across substrates and are typically found outside of the conditions with high CAZyme expression, as exemplified by the stages that are dominated by lipid and secondary metabolism
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