802 research outputs found

    An effective many-body theory for strongly interacting polar molecules

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    We derive a general effective many-body theory for bosonic polar molecules in strong interaction regime, which cannot be correctly described by previous theories within the first Born approximation. The effective Hamiltonian has additional interaction terms, which surprisingly reduces the anisotropic features of dipolar interaction near the shape resonance regime. In the 2D system with dipole moment perpendicular to the plane, we find that the phonon dispersion scales as \sqrt{|\bfp|} in the low momentum (\bfp) limit, showing the same low energy properties as a 2D charged Bose gas with Coulomb (1/r1/r) interactions.Comment: Same as published version (11 pages, 2 figure

    Imaging Galactic Dark Matter with High-Energy Cosmic Neutrinos

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    We show that the high-energy cosmic neutrinos seen by the IceCube Neutrino Observatory can be used to probe interactions between neutrinos and the dark sector that cannot be reached by current cosmological methods. The origin of the observed neutrinos is still unknown, and their arrival directions are compatible with an isotropic distribution. This observation, together with dedicated studies of Galactic plane correlations, suggests a predominantly extragalactic origin. Interactions between this isotropic extragalactic flux and the dense dark matter (DM) bulge of the Milky Way would thus lead to an observable imprint on the distribution, which would be seen by IceCube as (i) slightly suppressed fluxes at energies below a PeV and (ii) a deficit of events in the direction of the Galactic center. We perform an extended unbinned likelihood analysis using the four-year high-energy starting event data set to constrain the strength of DM-neutrino interactions for two model classes. We find that, in spite of low statistics, IceCube can probe regions of the parameter space inaccessible to current cosmological methods.National Science Foundation (U.S.) (Grant PHY-1505858)National Science Foundation (U.S.) (Grant PHY-1505855

    Development of Generalized Correlation for Electrical Conductivity Prediction of Pure Ionic Liquid

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    Ionic liquids are salts in liquid form that are composed of short-lived ion pairs. They are the new trend of solvent because of their very low vapor pressure, good chemical and thermal stability, and melting temperatures lower than 100°C. Pure ionic liquids contain ions that can conduct electricity or serve as electrolytes. But experimentation using ionic liquids would be expensive. This study aims to develop a generalized correlation for the electrical conductivity prediction of pure ionic liquids. The researchers gathered data of pure ionic liquids that involved the electrical conductivity property from the ThermoIL Database. The collected data were then trimmed based on a developed scheme and classifications. After trimming the data, the researchers evaluated the data using MATLAB software. The residual value was calculated, and a parity plot was constructed to test the models’ accuracy. The researchers gathered 2,425 data points from 310 references and were trimmed to 220 data points from 21 references. The parity plot and graph of the residuals plotted against pressure showed that the experimental and calculated values were close. Results showed that the electrical conductivity of pure ionic liquids could be predicted using a model patterned to Pitzer correlation with reduced temperature and reduced pressure as variables. Data with two or more references and low uncertainty made a good result on the models to create a generalized correlation via curve fitting

    LMT/AzTEC observations of Vega

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    Vega is the prototypical debris disc system. Its architecture has been extensively studied at optical to millimetre wavelengths, revealing a near face-on, broad, and smooth disc with multiple distinct components. Recent millimetre-wavelength observations from ALMA spatially resolved the inner edge of the outer, cold planetesimal belt from the star for the first time. Here we present early science imaging observations of the Vega system with the AzTEC instrument on the 32-m LMT, tracing extended emission from the disc out to 150 au from the star. We compare the observations to three models of the planetesimal belt architecture to better determine the profile of the outer belt. A comparison of these potential architectures for the disc does not significantly differentiate between them with the modelling results being similar in many respects to the previous ALMA analysis, but differing in the slope of the outer region of the disc. The measured flux densities are consistent between the LMT (single dish) and ALMA (interferometric) observations after accounting for the differences in wavelength of observation. The LMT observations suggest the outer slope of the planetesimal belt is steeper than was suggested in the ALMA analysis. This would be consistent with the interferometric observations being mostly blind to structure at the disc outer edges, but the overall low signal to noise of the LMT observations does not definitively resolve the structure of the outer planetesimal belt.FK and JPM acknowledge research support by the Ministry of Science and Technology of Taiwan under grant MOST107-2119-M-001-031-MY3, and Academia Sinica under grant AS-IA-106-M03. JPM acknowledges research support by the Ministry of Science and Technology of Taiwan under grant MOST109-2112-M-001-036-MY3. MC thanks Consejo Nacional de Ciencia y Tecnología (CONACyT) for financial support through grant CB-2015-256961

    Factors influencing erythrocyte sedimentation rate in adults New evidence for an old test

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    The erythrocyte sedimentation rate (ESR) is a routine test for inflammation. Few studies have investigated the potential influence of lifestyle factors and common metabolic abnormalities on the ESR. This study investigates the influence of demographic factors, alcohol consumption, smoking, physical activity, obesity, and metabolic syndrome on the ESR in adults.This cross-sectional study covered 1472 individuals (44.5% males; age range, 18-91 years) randomly selected from the population of a Spanish municipality. The ESR was measured using a standardized method. We assessed habitual alcohol consumption in standard drinking units, along with tobacco smoking, regular physical exercise (by questionnaire), body mass index, and variables defining metabolic syndrome. Multivariate analyses were performed, including mean corpuscular volume and hemoglobin concentration in the models.The ESR was higher in females than in males, and increased steadily with age. Median ESR of females was 2-fold higher than that of males, and median ESR of individuals aged >65 years was 2-fold higher than that of individuals in the youngest category (ages 18-35 years). Body mass index, presence of metabolic syndrome, and smoking were independently and positively associated with higher ESR values. Light alcohol drinkers and individuals with high regular physical activity displayed lower ESR values than did alcohol abstainers and individuals with low physical activity, respectively.ESR varies greatly with age and sex, and corresponding reference values are proposed. Lifestyle factors (physical activity, smoking, and alcohol consumption) and common metabolic abnormalities (obesity and related metabolic syndrome) may also influence ESR values

    Machismo, marianismo, and negative cognitive-emotional factors: Findings from the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study.

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    There is limited research on the traditional Hispanic male and female gender roles of machismo and marianismo, respectively, in relation to negative cognitions and emotions. Given the vulnerability of Hispanics to negative cognitions and emotions, it is important to examine sociocultural correlates of emotional distress. Therefore, we examined associations of machismo and marianismo with negative cognitive-emotional factors (i.e., depression symptoms; cynical hostility; and trait anxiety and anger) in the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study, a cross-sectional cohort study of sociocultural and psychosocial correlates of cardiometabolic health. Participants were aged 18–74 years and self-identified as Hispanic of Central American, Cuban, Dominican, Mexican, Puerto Rican, South American, and other Hispanic background (N = 4,426). Results revealed that specific components of machismo (traditional machismo) and marianismo (family and spiritual pillar dimensions) were associated with higher levels of negative cognitions and emotions after adjusting for socio-demographic factors (p < .05); these associations remained consistent across sex, Hispanic background group, and acculturation. Findings can inform mental health interventions and contribute to our understanding of the importance of gender role socialization in the context of self-reported negative cognitive-emotional factors in Hispanics

    Improving the operating efficiency of the more electric aircraft concept through optimised flight procedures

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    The increasing awareness of the environmental risks and costs due to the growing demand in aviation has prompted both academic and industrial research into short-term and long-term technologies which could help address the challenges. Among these, the more electric aircraft has been identified as a key design concept which would make aircraft more environmentally friendly and cost effective in the long run. Moreover, the notion of free-flight and optimised trajectories has been identified as a key operational concept which would help curb the environmental effects of aircraft as well as reduce overall costs. The research in this paper presents a methodology in which these two concepts can be coupled to study the benefits of more electric aircraft (MEA) flying optimised trajectories. A wide range of issues from aircraft performance, engine performance, airframe systems operation, power off-take penalties, emission modelling, optimisation algorithms and optimisation frameworks has been addressed throughout the study. The case study is based on a popular short haul flight between London Heathrow and Amsterdam Schiphol. The culmination of the study establishes the advantage of the MEA over conventional aircraft and also addresses the enhanced approach to the classical aircraft trajectory optimisation problem. The study shows that the operation procedures to achieve a minimum fuel burn are significantly different for a conventional aircraft and MEA. Trajectory optimisation reduced the fuel burn by 17.4% for the conventional aircraft and 12.2% for the more electric compared to the respective baseline cases. Within the constraints of the study, the minimum fuel burn trajectory for the MEA consumed 9.9% less fuel than the minimum fuel burn trajectory for the conventional aircraft

    All-flavour search for neutrinos from dark matter annihilations in the Milky Way with IceCube/DeepCore

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    We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string con-figuration during 2011–2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged self-annihilation cross-section, σAv, for dark matter candidate masses ranging from 30 GeV up to 10 TeV, assuming both a cuspy and a flat-cored dark matter halo profile. For dark matter masses between 200 GeV and 10 TeV, the results improve on all previous IceCube results on σAv, reaching a level of 10−23 cm3 s−1, depending on the annihilation channel assumed, for a cusped NFW profile. The analysis demonstrates that all-flavour searches are competitive with muon channel searches despite the intrinsically worse angular resolution of cascades compared to muon tracks in IceCube.SCOAP

    Integration of the practice of mindfulness within action learning as an added component within a post graduate leadership programme: an account of practice

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    This account of practice provides a practical example of the use of mindfulness practice within action learning which was a component of a bespoke UK Business School post-graduate leadership development programme commissioned by an English NHS Mental Health Trust aimed at improving the leadership capacity of mid-level managers through work-based learning. The article discusses background and context of the programme followed by how application of mindfulness exercises was integrated within the action learning process to encourage participants to be ‘in the moment’ as an added component of their leadership development. The aim of the paper is to share examples of practice applied within action learning. Finally, the paper asserts that the application of mindfulness exercises helped to enhance the action learning process by creating a calm, focused space for individual and collective reflections, enhancing the quality of engagement and enabling action learning members to take a more pragmatic approach to addressing the work issues raised within the action learning sets

    Searches for relativistic magnetic monopoles in IceCube

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    Various extensions of the Standard Model motivate the existence of stable magnetic monopoles that could have been created during an early high-energy epoch of the Universe. These primordial magnetic monopoles would be gradually accelerated by cosmic magnetic fields and could reach high velocities that make them visible in Cherenkov detectors such as IceCube. Equivalently to electrically charged particles, magnetic monopoles produce direct and indirect Cherenkov light while traversing through matter at relativistic velocities. This paper describes searches for relativistic ( v≥0.76cv≥0.76c ) and mildly relativistic ( v≥0.51cv≥0.51c ) monopoles, each using one year of data taken in 2008/2009 and 2011/2012, respectively. No monopole candidate was detected. For a velocity above 0.51c0.51c the monopole flux is constrained down to a level of 1.55×10−18cm−2s−1sr−11.55×10−18cm−2s−1sr−1 . This is an improvement of almost two orders of magnitude over previous limits.SCOAP
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