13,530 research outputs found
Z lineshape and forward-backward asymmetries
Preliminary but close to final results on the Z lineshape and
Forward-Backward asymmetries from the four LEP experiments are presented.
Combined values extracted from ALEPH. DELPHI, L3 and OPAL data recorded at
energies around the Z pole are discussed.Comment: 5 pages, 6 figures, sunbmitted to the Vancouver conference, ICHEP'9
Optimising the signal-to-noise ratio in measurement of photon pairs with detector arrays
To evidence multimode spatial entanglement of spontaneous down-conversion,
detector arrays allow a full field measurement, without any a priori selection
of the paired photons. We show by comparing results of the recent literature
that electron-multiplying CCD (EMCCD) cameras allow, in the present state of
technology, the detection of quantum correlations with the best signal-to-noise
ratio (SNR), while intensified CCD (ICCD) cameras allow at best to identify
pairs. The SNR appears to be proportional to the square root of the number of
coherence cells in each image, or Schmidt number. Then, corrected estimates are
derived for extended coherence cells and not very low and not space-stationary
photon fluxes. Finally, experimental measurements of the SNR confirm our model
El papel actual y tendencias del rol de la papa en la alimentacion en America Latina y el mundo
Temporal ghost imaging with twin photons
We use twin photons generated by spontaneous parametric down conversion to perform temporal ghost imaging of a single time signal. The retrieval of a binary signal containing eight bits is performed with an error rate below 1%
Central potential and examples of hidden algebra structure
We propose two generalisations of the Coulomb potential equation of quantum
mechanics and investigate the occurence of algebraic eigenfunctions for the
corresponding Scrh\"odinger equations. Some relativistic counterparts of these
problems are also discussed.Comment: 8 pages, latex, no figure
Social heterogeneity in self-reported health status and measurement of inequalities in health
This study aims to analyse the impact of the measurement of health status on socioeconomic inequalities in health. A MIMIC model with structural equations is used to create a latent variable of health status from four health indicators: self-assessed health, report of chronic diseases, report of activity limitations and mental health. Then, we disentangle the impact of sociodemographic characteristics on latent health from their direct impact on each heath indicator and discuss their effects on the assessment of socioeconomic inequalities in health. This study emphasises differences in inequalities in health according to latent health. In addition, it suggests the existence of reporting heterogeneity biases. For a given latent health status, women and old people are more likely to report chronic diseases. Mental health problems are over-reported by women and isolated people and under-reported by the oldest people. Active and retired people as well as non manual workers in the top of the social hierarchy more often report activity limitations. Finally, highly educated and socially advantaged people more often report chronic diseases whereas less educated people under-report a poor self-assessed health. To conclude, the four health indicators suffer from reporting heterogeneity biases and the report of chronic diseases is the indicator which biases the most the measurement of socioeconomic inequalities in health.inequalities in health - MIMIC - reporting bias - structural equations
Microspore embryogenesis in barley: anther pre-treatment stimulates plant defence gene expression
Microspore embryogenesis (ME) is a process in which the gametophytic pollen programme of the microspore is reorientated towards a new embryo sporophytic programme. This process requires a stress treatment, usually performed in the anther or isolated microspores for several days. Despite the universal use of stress to induce ME, very few studies have addressed the physiological processes that occur in the anther during this step. To further understand the processes triggered by stress treatment, we followed the response of anthers by measuring the expression of stress-related genes in two barley (Hordeum vulgare L.) cultivars differing in their ME response. Genes encoding enzymes involved in oxidative stress (glutathione-S-transferase, GST; oxalate oxidase, OxO), in the synthesis of jasmonic acid (13-lipoxygenase, Lox; allene oxide cyclase, AOC; allene oxide synthase, AOS) and in the phenylpropanoid pathway (phenylalanine ammonia lyase, PAL), as well as those encoding PR proteins (Barwin, chitinase 2b, Chit 2b; glucanase, Gluc; basic pathogenesis-related protein 1, PR1; pathogenesis-related protein 10, PR10) were up-regulated in whole anthers upon stress treatment, indicating that anther perceives stress and reacts by triggering general plant defence mechanisms. In particular, both OxO and Chit 2b genes are good markers of anther reactivity owing to their high level of induction during the stress treatment. The effect of copper sulphate appeared to limit the expression of defence-related genes, which may be correlated with its positive effect on the yield of microspor
Bats, coronaviruses, and deforestation: Toward the emergence of novel infectious diseases?
Coronaviruses (CoV) were for a long time associated with several major veterinary diseases such as avian infectious coronavirus, calf diarrhea, winter dysentery, respiratory infections (BRD-BCoV) in cattle, SDCV, PEDV, SECD in swine and dog, intestinal disease or Feline Infectious Peritonitis (Saif, 2014), and the human mild and common cold. However, SARS emerged in 2002 in China and spread across 29 other countries with a 10% death rate. More recently, the MERS-CoV outbreak in Saudi Arabia in 2012 displayed a death rate of 38%. The emergence of these two events of highly pathogenic CoVs shed light on the threat posed by coronaviruses to humans. Bats are hosting many viruses (Calisher et al., 2006) and in particular coronaviruses, which represent 31% of their virome (Chen et al., 2014). Furthermore, bats display a remarkable resistance to viruses (Omatsu et al., 2007; Storm et al., 2018). The risk of emergence of a novel bat-CoV disease can therefore be envisioned
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