598 research outputs found

    Ultra-cold atoms in an optical cavity: two-mode laser locking to the cavity avoiding radiation pressure

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    The combination of ultra-cold atomic clouds with the light fields of optical cavities provides a powerful model system for the development of new types of laser cooling and for studying cooperative phenomena. These experiments critically depend on the precise tuning of an incident pump laser with respect to a cavity resonance. Here, we present a simple and reliable experimental tuning scheme based on a two-mode laser spectrometer. The scheme uses a first laser for probing higher-order transversal modes of the cavity having an intensity minimum near the cavity's optical axis, where the atoms are confined by a magnetic trap. In this way the cavity resonance is observed without exposing the atoms to unwanted radiation pressure. A second laser, which is phase-locked to the first one and tuned close to a fundamental cavity mode drives the coherent atom-field dynamics.Comment: 7 pages, 7 figure

    Ensemble of Hankel Matrices for Face Emotion Recognition

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    In this paper, a face emotion is considered as the result of the composition of multiple concurrent signals, each corresponding to the movements of a specific facial muscle. These concurrent signals are represented by means of a set of multi-scale appearance features that might be correlated with one or more concurrent signals. The extraction of these appearance features from a sequence of face images yields to a set of time series. This paper proposes to use the dynamics regulating each appearance feature time series to recognize among different face emotions. To this purpose, an ensemble of Hankel matrices corresponding to the extracted time series is used for emotion classification within a framework that combines nearest neighbor and a majority vote schema. Experimental results on a public available dataset shows that the adopted representation is promising and yields state-of-the-art accuracy in emotion classification.Comment: Paper to appear in Proc. of ICIAP 2015. arXiv admin note: text overlap with arXiv:1506.0500

    Highly versatile atomic micro traps generated by multifrequency magnetic field modulation

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    We propose the realization of custom-designed adiabatic potentials for cold atoms based on multimode radio frequency radiation in combination with static inhomogeneous magnetic fields. For example, the use of radio frequency combs gives rise to periodic potentials acting as gratings for cold atoms. In strong magnetic field gradients the lattice constant can be well below 1 micrometer. By changing the frequencies of the comb in time the gratings can easily be propagated in space, which may prove useful for Bragg scattering atomic matter waves. Furthermore, almost arbitrarily shaped potential are possible such as disordered potentials on a scale of several 100 nm or lattices with a spatially varying lattice constant. The potentials can be made state selective and, in the case of atomic mixtures, also species selective. This opens new perspectives for generating tailored quantum systems based on ultra cold single atoms or degenerate atomic and molecular quantum gases.Comment: 12 pages, 6 figure

    Traffic-Related Air Pollution and All-Cause Mortality during Tuberculosis Treatment in California.

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    BackgroundAmbient air pollution and tuberculosis (TB) have an impact on public health worldwide, yet associations between the two remain uncertain.ObjectiveWe determined the impact of residential traffic on mortality during treatment of active TB.MethodsFrom 2000-2012, we enrolled 32,875 patients in California with active TB and followed them throughout treatment. We obtained patient data from the California Tuberculosis Registry and calculated traffic volumes and traffic densities in 100- to 400-m radius buffers around residential addresses. We used Cox models to determine mortality hazard ratios, controlling for demographic, socioeconomic, and clinical potential confounders. We categorized traffic exposures as quintiles and determined trends using Wald tests.ResultsParticipants contributed 22,576 person-years at risk. There were 2,305 deaths during treatment for a crude mortality rate of 1,021 deaths per 10,000 person-years. Traffic volumes and traffic densities in all buffers around patient residences were associated with increased mortality during TB treatment, although the findings were not statistically significant in all buffers. As the buffer size decreased, fifth-quintile mortality hazards increased, and trends across quintiles of traffic exposure became more statistically significant. Increasing quintiles of nearest-road traffic volumes in the 100-m buffer were associated with 3%, 14%, 19%, and 28% increased risk of death during TB treatment [first quintile, referent; second quintile hazard ratio (HR)=1.03 [95% confidence interval (CI): 0.86, 1.25]; third quintile HR=1.14 (95% CI: 0.95, 1.37); fourth quintile HR=1.19 (95% CI: 0.99, 1.43); fifth quintile HR=1.28 (95% CI: 1.07, 1.53), respectively; p-trend=0.002].ConclusionsResidential proximity to road traffic volumes and traffic density were associated with increased all-cause mortality in patients undergoing treatment for active tuberculosis even after adjusting for multiple demographic, socioeconomic, and clinical factors, suggesting that TB patients are susceptible to the adverse health effects of traffic-related air pollution. https://doi.org/10.1289/EHP1699

    Experiences that \u201creach the heart\u201d. Taking part in a whole body dissection course at the University of Malta

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    This article summarizes the activities of the four-week whole body dissection course the main authors participated in in August 2016 at the dissection hall of the University of Malta (UoM). Our team comprised 10 second-year medicine students from University of Palermo chosen among who had passed the Human Anatomy exam brilliantly. The need to move to the UoM to take part in such activity derives from the lack of practice approach in Italian schools of medicine, focused mostly on the theoretical studies, neglecting practical experience. The heart dissection reveal itself as a huge opportunity to finally apply our anatomical knowledge, improving it and enabling us to compare images took from books to the actual organ. We had the chance to handle a real heart, to appreciate its weight and consistence. We took part in coronary artery courses focusing on their functions within the heart machinery.This article summarizes the activities of the four-week whole body dissection course the main authors partecipated in August 2016 at the dissection hall of the University of Malta (UoM). Our team comprised 10 second-year medicine students from University of Palermo chosen among who had passed the Human Anatomy exam brilliantly. The need to molve to the UoM to take part in such activity derives from the lack of practice approach in Italian schools of medicine, focused mostly on the theoretical studies, neglecting practical experience. The heart dissection reveal itself as a huge opportunity to finally apply our anatomical knowledge, improving it and enabling us to compare image took from books to the actual organ. We had the chance to handle a real heart, to appreciate its weight and consistence. We took part in coronary artery courses focusing on their functions within the heart machinery

    Negative Effect of Smoking on the Performance of the QuantiFERON TB Gold in Tube Test.

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    False negative and indeterminate Interferon Gamma Release Assay (IGRA) results are a well documented problem. Cigarette smoking is known to increase the risk of tuberculosis (TB) and to impair Interferon-gamma (IFN-γ) responses to antigenic challenge, but the impact of smoking on IGRA performance is not known. The aim of this study was to evaluate the effect of smoking on IGRA performance in TB patients in a low and high TB prevalence setting respectively. Patients with confirmed TB from Denmark (DK, n = 34; 20 smokers) and Tanzania (TZ, n = 172; 23 smokers) were tested with the QuantiFERON-TB Gold In tube (QFT). Median IFN-γ level in smokers and non smokers were compared and smoking was analysed as a risk factor for false negative and indeterminate QFT results. Smokers from both DK and TZ had lower IFN-γ antigen responses (median 0.9 vs. 4.2 IU/ml, p = 0.04 and 0.4 vs. 1.6, p < 0.01), less positive (50 vs. 86%, p = 0.03 and 48 vs. 75%, p < 0.01) and more false negative (45 vs. 0%, p < 0.01 and 26 vs. 11%, p = 0.04) QFT results. In Tanzanian patients, logistic regression analysis adjusted for sex, age, HIV and alcohol consumption showed an association of smoking with false negative (OR 17.1, CI: 3.0-99.1, p < 0.01) and indeterminate QFT results (OR 5.1, CI: 1.2-21.3, p = 0.02). Cigarette smoking was associated with false negative and indeterminate IGRA results in both a high and a low TB endemic setting independent of HIV status

    Science-based regulation of endocrine disrupting chemicals in Europe: which approach?

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    Endocrine disruptors are defined by WHO as “exogenous compounds or mixtures that alter function(s) of the endocrine system and consequently cause adverse effects in an intact organism, or its progeny, or (sub)populations”.1 European Union (EU) laws on pesticides (plant protection products regulation [PPPR]) and biocide products regulation (BPR), enacted in 2009 and 2012, respectively, place restrictions on the use of active substances with severe forms of toxicity, including carcinogenicity, mutagenicity, reproductive toxicity, and endocrine disruption

    EU regulation of endocrine disruptors: a missed opportunity

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    The European Commission (EC) has missed a unique opportunity to develop a regulatory system that sets new standards in the protection against endocrine-disrupting chemicals. The proposed amendments to the European Union (EU) pesticide law and the criteria for the identification of endocrine disruptors that the EC published on June 15, 2016, after a delay of almost 3 years,1 ensure that hardly any endocrine disruptors used as pesticides will be barred from commerce

    Controlled generation of momentum states in a high-finesse ring cavity

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    A Bose-Einstein condensate in a high-finesse ring cavity scatters the photons of a pump beam into counterpropagating cavity modes, populating a bi-dimensional momentum lattice. A high-finesse ring cavity with a sub-recoil linewidth allows to control the quantized atomic motion, selecting particular discrete momentum states and generating atom-photon entanglement. The semiclassical and quantum model for the 2D collective atomic recoil lasing (CARL) are derived and the superradiant and good-cavity regimes discussed. For pump incidence perpendicular to the cavity axis, the momentum lattice is symmetrically populated. Conversely, for oblique pump incidence the motion along the two recoil directions is unbalanced and different momentum states can be populated on demand by tuning the pump frequency.Comment: Submitted to EPJ-ST Special Issue. 10 pages and 3 figure
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