188 research outputs found
Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives
Recent theoretical and experimental studies highlight the possibility of new
fundamental particle physics beyond the Standard Model that can be probed by
sub-eV energy experiments. The OSQAR photon regeneration experiment looks for
"Light Shining through a Wall" (LSW) from the quantum oscillation of optical
photons into "Weakly Interacting Sub-eV Particles" (WISPs), like axion or
axion-like particles (ALPs), in a 9 T transverse magnetic field over the
unprecedented length of m. No excess of events has been
detected over the background. The di-photon couplings of possible new light
scalar and pseudo-scalar particles can be constrained in the massless limit to
be less than GeV. These results are very close to the
most stringent laboratory constraints obtained for the coupling of ALPs to two
photons. Plans for further improving the sensitivity of the OSQAR experiment
are presented.Comment: 7 pages, 7 figure
Reindexing a Research Repository from the Ground up: Adding and Evaluating Quality Metadata
Latest Results of the OSQAR Photon Regeneration Experiment for Axion-Like Particle Search
The OSQAR photon regeneration experiment searches for pseudoscalar and scalar
axion-like particles by the method of "Light Shining Through a Wall", based on
the assumption that these weakly interacting sub-eV particles couple to two
photons to give rise to quantum oscillations with optical photons in strong
magnetic field. No excess of events has been observed, which constrains the
di-photon coupling strength of both pseudoscalar and scalar particles down to
GeV in the massless limit. This result is the most
stringent constraint on the di-photon coupling strength ever achieved in
laboratory experiments.Comment: 6 pages, 5 figures. appears in Proceedings of the 10th PATRAS
Workshop on Axions, WIMPs and WISPs (2014
Policymakersā and other stakeholdersā perceptions of key considerations for health system decisions and the presentation of evidence to inform those considerations: an international survey
ZaŔtitno djelovanje selenija protiv prekomjerne ekspresije apoptotskih gena povezanih s karcinomom u Ŕtakora izloženih o-krezolu
Cresols are monomethyl derivatives of phenol frequently used as solvents and intermediates in the production of disinfectants, fragrances, pesticides, dyes, and explosives, which is probably why they are widely distributed in the environment. General population may be exposed to cresols mainly through inhalation of contaminated air. In this study we evaluated the toxicological effects of o-cresol on differential gene expression profile of rat liver and prostate. Experiments were conducted on 80 male rats, 60 of which were exposed to o-cresol (1.5 g kg-1, 5 g kg-1, or 15 g kg-1) through feed for 8 weeks. Three groups of rats were supplemented with 0.1 mg kg-1 selenium (Se, in the form of, sodium selenite) in addition to o-cresol to evaluate its effectiveness against o-cresol toxicity. Control group received neither o-cresol nor Se, while one group received Se alone. Survival was similar between the exposed and control animals. Rats exposed to 15 g kg-1 of o-cresol showed a 16 % loss in body weight by the end of the study, which may have been related to o-cresol making feed unpalatable at this concentration. Liver and prostate tissue samples were collected at the end of the treatment. mRNA analysis revealed that apoptotic genes (CYP3A, COX-2, PPARĪ³, BAX, BCL2, AKT-1, and PKCĪ±) related to cancer were up-regulated in liver and prostate tissues isolated from groups exposed to 5 g kg-1 and 15 g kg-1 o-cresol in comparison to control. Changes in gene expression profile were prevented when rats were supplemented with Se. The exact mechanisms underlying its protective effect remain to be clarified by future studies.Krezoli su monometilni derivati fenola koji se Äesto rabe kao otapala te kao posrednici u proizvodnji dezinfekcijskih sredstava, mirisa, pesticida, boja i eksploziva. Otuda i njihova rasprostranjenost u okoliÅ”u. OpÄa je populacija izložena krezolima uglavnom putem zraka. U ovome se toksikoloÅ”kom istraživanju ocijenilo djelovanje o-krezola, jednoga od tri krezolova izomera, na ekspresiju gena u tkivima jetre i prostate mužjaka Å”takora. Istraživanje je provedeno na 80 mužjaka, od kojih je 60 tijekom osam tjedana bilo izloženo o-krezolu (1,5 g kg-1, 5 g kg-1, odnosno 15 g kg-1) preko krmiva. Tri skupine Å”takora primale su uz o-krezol nadomjestak selenija u dozi od 0.1 mg kg-1 (Se, u obliku natrijeva selenita) radi ocjene njegove djelotvornosti protiv toksiÄnosti o-krezola. Kontrolna skupina nije
primala ni o-krezol ni Se, dok je jedna skupina primala samo Se. Preživljenje je bilo podjednako u svih skupina životinja. Å takori izloženi najviÅ”oj dozi o-krezola (15 g kg-1) imali su 16 % manju tjelesnu masu od kontrolne skupine na kraju ispitivanja, Å”to može biti povezano s loÅ”im okusom krmiva zbog primjese visoke doze o-krezola. S istekom osmotjednoga izlaganja o-krezolu životinje su eutanazirane te su prikupljeni uzorci tkiva jetre i prostate. Analiza m-RNA pokazala je znaÄajno poviÅ”enu ekspresiju apoptotskih gena CYP3A, COX-2, PPARĪ³, BAX, BCL2, AKT-1 i PKCĪ±, koji su povezani s nastankom karcinoma u skupinama Å”takora
izloženim o-krezolu (5 g kg-1 i 15 g kg-1 u odnosu na kontrolu. Ova je prekomjerna ekspresija poniÅ”tena u Å”takora koji su primali selenij. JoÅ” nisu jasni mehanizmi iza ovoga zaÅ”titnog djelovanja, na Å”to Äe odgovoriti buduÄa istraživanja
New games, new rules: big data and the changing context of strategy
Big data and the mechanisms by which it is produced and disseminated introduce important changes in the ways information is generated and made relevant for organizations. Big data often represents miscellaneous records of the whereabouts of large and shifting online crowds. It is frequently agnostic, in the sense of being produced for generic purposes or purposes different from those sought by big data crunching. It is based on varying formats and modes of communication (e.g., texts, image and sound), raising severe problems of semiotic translation and meaning compatibility. Crucially, the usefulness of big data rests on their steady updatability, a condition that reduces the time span within which this data is useful or relevant. Jointly, these attributes challenge established rules of strategy making as these are manifested in the canons of procuring structured information of lasting value that addresses specific and long-term organizational objectives. The developments underlying big data thus seem to carry important implications for strategy making, and the data and information practices with which strategy has been associated. We conclude by placing the understanding of these changes within the wider social and institutional context of longstanding data practices and the significance they carry for management and organizations
The water vapour continuum in near-infrared windows ā current understanding and prospects for its inclusion in spectroscopic databases
Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earthās atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cmā1) and include reference to the window centred on 2600 cmā1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback ā cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum ā as an example, we report pilot measurements of the water vapour self-continuum using a supercontinuum laser source coupled to an FTS. Such improvements, as well as additional measurements and analyses in other laboratories, would enable the inclusion of the water vapour continuum in future spectroscopic databases, and therefore allow for a more reliable forward modelling of the radiative properties of the atmosphere. It would also allow a more confident assessment of different theoretical descriptions of the underlying cause or causes of continuum absorption
Evaluation of a Web Portal for Improving Public Access to Evidence-Based Health Information and Health Literacy Skills: A Pragmatic Trial
Background: Using the conceptual framework of shared decision-making and evidence-based practice, a web portal was
developed to serve as a generic (non disease-specific) tailored intervention to improve the lay publicās health literacy skills.
Objective: To evaluate the effects of the web portal compared to no intervention in a real-life setting.
Methods: A pragmatic randomised controlled parallel trial using simple randomisation of 96 parents who had children aged
,4 years. Parents were allocated to receive either access to the portal or no intervention, and assigned three tasks to
perform over a three-week period. These included a searching task, a critical appraisal task, and reporting on perceptions
about participation. Data were collected from March through June 2011.
Results: Use of the web portal was found to improve attitudes towards searching for health information. This variable was
identified as the most important predictor of intention to search in both samples. Participants considered the web portal to
have good usability, usefulness, and credibility. The intervention group showed slight increases in the use of evidencebased
information, critical appraisal skills, and participation compared to the group receiving no intervention, but these
differences were not statistically significant.
Conclusion: Despite the fact that the study was underpowered, we found that the web portal may have a positive effect on
attitudes towards searching for health information. Furthermore, participants considered the web portal to be a relevant
tool. It is important to continue experimenting with web-based resources in order to increase user participation in health
care decision-making.
Trial Registration: ClinicalTrials.gov NCT0126679
Modeling of Ti-W Solidification Microstructures Under Additive Manufacturing Conditions
Additive manufacturing (AM) processes have many benefits for the fabrication of alloy parts, including the potential for greater microstructural control and targeted properties than traditional metallurgy processes. To accelerate utilization of this process to produce such parts, an effective computational modeling approach to identify the relationships between material and process parameters, microstructure, and part properties is essential. Development of such a model requires accounting for the many factors in play during this process, including laser absorption, material addition and melting, fluid flow, various modes of heat transport, and solidification. In this paper, we start with a more modest goal, to create a multiscale model for a specific AM process, Laser Engineered Net Shaping (LENSā¢), which couples a continuum-level description of a simplified beam melting problem (coupling heat absorption, heat transport, and fluid flow) with a Lattice Boltzmann-cellular automata (LB-CA) microscale model of combined fluid flow, solute transport, and solidification. We apply this model to a binary Ti-5.5 wt pct W alloy and compare calculated quantities, such as dendrite arm spacing, with experimental results reported in a companion paper
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