19,322 research outputs found
Bloom-Gilman duality of the nucleon structure function and the elastic peak contribution
The occurrence of the Bloom-Gilman duality in the nucleon structure function
is investigated by analyzing the Q**2-behavior of low-order moments, both
including and excluding the contribution arising from the nucleon elastic peak.
The Natchmann definition of the moments has been adopted in order to cancel out
target-mass effects. It is shown that the onset of the Bloom-Gilman duality
occurs around Q**2 ~ 2 (GeV/c)**2 if only the inelastic part of the nucleon
structure function is considered, whereas the inclusion of the nucleon elastic
peak contribution leads to remarkable violations of the Bloom-Gilman duality.Comment: in Proc. of the XVI European Conference on Few-body Problems in
Physics, Autrans (France), July 199
Using Wikipedia with associative networks for document classification
We demonstrate a new technique for building associative networks based on Wikipedia, comparing them to WordNet-based associative networks that we used previously, nding the Wikipedia-based networks to perform better at document classification. Additionally, we compare the performance of associative networks to various other text classification techniques using the Reuters-21578 dataset, establishing that associative networks can achieve comparable results
Hypothalamically-Induced Insulin Release and its Potentiation During Oral and Intravenous Glucose Loads
Male Wistar rats were provided with bilateral cannulas in the lateral hypothalamic area (LHA) and cannulas in the left and right jugular vein. Freely moving rats provided in this way with cannulas were infused with transmitters in the LHA and with various substances in the blood circulation during simultaneous sampling of blood without disturbing the animals. Infusion of norepinephrine (NE) in the LHA resulted in increased insulin levels while plasma glucagon and blood glucose were nearly not affected. This LHA mediated insulin release was suppressed by atropine injection in the blood circulation suggesting a vagal contribution to the observed phenomenon. Administration of either an oral or i.v. glucose load during noradrenergic stimulation of the LHA elicited an exaggerated insulin response when compared to their controls. This LHA potentiated insulin response during an oral and i.v. glucose load could be suppressed by atropinization of the rats. It is concluded that meal-related stimuli are relayed to the NE-stimulated area of the LHA and that these stimuli modulate the output from this area of the LHA that is concerned with the release of insulin.
The Environments of Short-Duration Gamma-Ray Bursts and Implications for their Progenitors
[Abridged] The study of short-duration gamma-ray bursts (GRBs) experienced a
complete revolution in recent years thanks to the discovery of the first
afterglows and host galaxies in May 2005. These observations demonstrated that
short GRBs are cosmological in origin, reside in both star forming and
elliptical galaxies, are not associated with supernovae, and span a wide
isotropic-equivalent energy range of ~10^48-10^52 erg. However, a fundamental
question remains unanswered: What are the progenitors of short GRBs? The most
popular theoretical model invokes the coalescence of compact object binaries
with neutron star and/or black hole constituents. However, additional
possibilities exist, including magnetars formed through prompt channels
(massive star core-collapse) and delayed channels (binary white dwarf mergers,
white dwarf accretion-induced collapse), or accretion-induced collapse of
neutron stars. In this review I summarize our current knowledge of the galactic
and sub-galactic environments of short GRBs, and use these observations to draw
inferences about the progenitor population. The most crucial results are: (i)
some short GRBs explode in dead elliptical galaxies; (ii) the majority of short
GRBs occur in star forming galaxies; (iii) the star forming hosts of short GRBs
are distinct from those of long GRBs (lower star formation rates, and higher
luminosities and metallicities), and instead appear to be drawn from the
general field galaxy population; (iv) the physical offsets of short GRBs
relative to their host galaxy centers are significantly larger than for long
GRBs; (v) the observed offset distribution is in good agreement with
predictions for NS-NS binary mergers; and (vi) short GRBs trace under-luminous
locations within their hosts, but appear to be more closely correlated with the
rest-frame optical light (old stars) than the UV light (young massive stars).Comment: Solicited review in New Astronomy Reviews; accepted version; 24
pages, 23 figures; version with full resolution figures available from
https://www.cfa.harvard.edu/~eberger/eberger_shb_nar.pd
Relationships between recovery experiences and well-being among younger and older teachers
Purpose: The study had three aims. We investigated, first, how six recovery experiences (i.e., detachment, relaxation, control, mastery, meaning, and affiliation) during off-job time suggested by the DRAMMA model (Newman et al. in J Happiness Stud 15(3):555–578. https://doi.org/10.1007/s10902-013-9435-x, 2014) are related to well-being (i.e., vitality, life satisfaction, and work ability). Second, we examined how age related to these outcomes, and third, we investigated whether age moderated the relationships between recovery experiences and well-being outcomes. Methods: A sample of 909 Finnish teachers responded to an electronic questionnaire (78% women, average age 51 years). The data were analyzed with moderated hierarchical regression analyses. Results: Detachment from work, relaxation, control, and mastery were associated with higher vitality. Detachment, relaxation, meaning, and affiliation were related to higher life satisfaction. Older age was related to lower work ability, but not to vitality or life satisfaction. Older teachers benefited more from control and mastery during off-job time than did younger teachers in terms of vitality, whereas younger teachers benefited more from relaxation in terms of all well-being outcomes. Conclusions: Detachment, relaxation, control, mastery, meaning, and affiliation during off-job time were related to higher well-being, supporting the DRAMMA model. Age moderated the relationships between control, mastery, and relaxation and vitality and life satisfaction. The role of aging in recovery from work needs further research
Comment on "Nucleon elastic form factors and local duality"
We comment on the papers "Nucleon elastic form factors and local duality"
[Phys. Rev. {\bf D62}, 073008 (2000)] and "Experimental verification of
quark-hadron duality" [Phys. Rev. Lett. {\bf 85}, 1186 (2000)]. Our main
comment is that the reconstruction of the proton magnetic form factor, claimed
to be obtained from the inelastic scaling curve thanks to parton-hadron local
duality, is affected by an artifact.Comment: to appear in Phys. Rev.
Strategies for Developing Sustainable Design Practice for Students and SME Professionals
Designers and engineers seem finally to be awakening to the challenge that sustainable development has given. Educators and students alike are keenly aware of the need to become more effective in the training and practice of their specific disciplines with respect to sustainability. \noindent In the past four years since this research has developed, there has been a marked change in the mass market appeal for sustainable products and services. Implementation of sustainable design practice from both recent graduates and also innovative small and medium enterprises (SMEs) at a local level is slow. One would assume that the consumer drive would push a change in design practice but perhaps the complexities of sustainable design along with the lack of experience in the field are providing barriers to designers and marketers alike. In addition the SME sector alone makes up the bulk of industry within the European Union (EU) varying in some countries from 80-95% of the total numbers of companies (Tukker et al. 2000). These industries by their nature find it difficult to dedicate expertise solely to sustainable development issues. The strategy outlined in this paper intended to introduce concepts of sustainable design thinking and practice to both SMEs and undergraduate students. \noindent This current and ongoing research qualitatively assesses appropriate models for educating for sustainable design thinking with SME employees and undergraduate design students. The sample groups include Industrial Design and Product Design undergraduate students in Ireland at the Institute of Technology, Carlow (IT Carlow), The University of Limerick (UL) and a sample of SMEs in the South East of Ireland, with broad national participation from other students of design and professionals from industry. Current levels of understanding of students and SME professionals of key environmental and social issues are measured
Sense of coherence, off-job crafting, and mental well-being: A path of positive health development
Our study examines the core concept of salutogenesis-sense of coherence (SOC)-in relation to off-job crafting (OJC) and mental well-being (MWB). The original salutogenic model of health mainly addresses the protective function of SOC against adversity. In our study, we focus on the recently proposed path of positive health development that captures how SOC can contribute to positive health and thriving. We present and test our theoretical assumptions about one such path, examining OJC as a possible mechanism how SOC translates into MWB. We tested our proposed model using cross-lagged panel model with three waves of panel data from Swiss and German employees (N = 2217). We compared our model to alternative nested models and conducted indirect effect analysis to test longitudinal mediation. Our hypothesized model fitted the data well and we found support for our main hypothesis that OJC partially mediates the relationship between SOC and MWB. Further, we identified positive reciprocal relationships between SOC and MWB, as well as between OJC and MWB. Overall, our study provides evidence that OJC is one mechanism underlying the recently postulated path of positive health development in the salutogenic model. For health promotion, this implies that promoting SOC and OJC may help to strengthen individual well-being and lead to positive feedback loops that foster personal development and thriving
Discovery of the Very Red Near-Infrared and Optical Afterglow of the Short-Duration GRB 070724A
[Abridged] We report the discovery of the near-infrared and optical afterglow
of the short-duration gamma-ray burst GRB070724A. The afterglow is detected in
i,J,H,K observations starting 2.3 hr after the burst with K=19.59+/-0.16 mag
and i=23.79+/-0.07 mag, but is absent in images obtained 1.3 years later.
Fading is also detected in the K-band between 2.8 and 3.7 hr at a 4-sigma
significance level. The optical/near-IR spectral index, beta_{O,NIR}=-2, is
much redder than expected in the standard afterglow model, pointing to either
significant dust extinction, A_{V,host}~2 mag, or a non-afterglow origin for
the near-IR emission. The case for extinction is supported by a shallow optical
to X-ray spectral index, consistent with the definition for ``dark bursts'',
and a normal near-IR to X-ray spectral index. Moreover, a comparison to the
optical discovery magnitudes of all short GRBs with optical afterglows
indicates that the near-IR counterpart of GRB070724A is one of the brightest to
date, while its observed optical emission is one of the faintest. In the
context of a non-afterglow origin, the near-IR emission may be dominated by a
mini-supernova, leading to an estimated ejected mass of M~10^-4 Msun and a
radioactive energy release efficiency of f~0.005 (for v~0.3c). However, the
mini-SN model predicts a spectral peak in the UV rather than near-IR,
suggesting that this is either not the correct interpretation or that the
mini-SN models need to be revised. Finally, the afterglow coincides with a star
forming galaxy at z=0.457, previously identified as the host based on its
coincidence with the X-ray afterglow position (~2" radius). Our discovery of
the optical/near-IR afterglow makes this association secure.Comment: Submitted to ApJ; 10 pages, 5 figures, 1 tabl
The origins of quark-hadron duality: How does the square of the sum become the sum of the squares?
Bloom-Gilman duality demonstrates empirically that the electroproduction of
's at low momentum transfers averages smoothly around the scaling curve
measured at large momentum transfers. The latter is proportional to the sum of
the squares of the constituent charges whereas the former involves the coherent
excitation of resonances and is driven by the square of summed constituent
charges. We determine the minimal necessary conditions for this equality to be
realised so that duality can occur and consider the implications for a range of
processes that may be studied soon at CEBAF.Comment: 9 page
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