206 research outputs found

    First results from the CERN Axion Solar Telescope (CAST)

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    Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.Comment: 4 pages, accepted by PRL. Final version after the referees comment

    Ellipsometric and Raman Spectroscopic Study of Thermally Formed Films on Titanium

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    Thermal films on titanium surfaces were formed by heating titanium samples in air at atmospheric pressure. The optical constants, thickness, and structure of the formed films at various temperatures and times of heating were investigated by ellipsometry and Raman spectroscopy. The complex index of refraction and the thickness of generated films were determined by comparing the experimental loci and obtained by ellipsometric measurements with theoretical computed vs. curves. It was found that the thickness in homogeneity and porosity of formed films increase with increasing temperature and the duration of the thermal treatment. Beyond a certain critical temperature, the appearance of some Raman bands and changes in their intensities indicated that the film transformed from amorphous to microcrystalline and crystalline structure

    The search for solar axions in the CAST experiment

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    The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: gaγ<0.9×1010_{a\gamma}<0.9\times10^{-10} GeV1^{-1} at 95% C.L. for axion masses ma<_{a} < 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV.The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: gaγ<0.9×1010_{a\gamma}<0.9\times10^{-10} GeV1^{-1} at 95% C.L. for axion masses ma<_{a} < 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV

    Multi-horizon air pollution forecasting with deep neural networks

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    Air pollution is a global problem, especially in urban areas where the population density is very high due to the diverse pollutant sources such as vehicles, industrial plants, buildings, and waste. North Macedonia, as a developing country, has a serious problem with air pollution. The problem is highly present in its capital city, Skopje, where air pollution places it consistently within the top 10 cities in the world during the winter months. In this work, we propose using Recurrent Neural Network (RNN) models with long short-term memory units to predict the level of PM10 particles at 6, 12, and 24 h in the future. We employ historical air quality measurement data from sensors placed at multiple locations in Skopje and meteorological conditions such as temperature and humidity. We compare different deep learning models’ performance to an Auto-regressive Integrated Moving Average (ARIMA) model. The obtained results show that the proposed models consistently outperform the baseline model and can be successfully employed for air pollution prediction. Ultimately, we demonstrate that these models can help decision-makers and local authorities better manage the air pollution consequences by taking proactive measures

    Value of T2 Mapping MRI for Prostate Cancer Detection and Classification.

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    Currently, multi-parametric prostate MRI (mpMRI) consists of a qualitative T &lt;sub&gt;2&lt;/sub&gt; , diffusion weighted, and dynamic contrast enhanced imaging. Quantification of T &lt;sub&gt;2&lt;/sub&gt; imaging might further standardize PCa detection and support artificial intelligence solutions. To evaluate the value of T &lt;sub&gt;2&lt;/sub&gt; mapping to detect prostate cancer (PCa) and to differentiate PCa aggressiveness. Retrospective single center cohort study. Forty-four consecutive patients (mean age 67 years; median PSA 7.9 ng/mL) with mpMRI and verified PCa by subsequent targeted plus systematic MR/ultrasound (US)-fusion biopsy from February 2019 to December 2019. Standardized mpMRI at 3 T with an additionally acquired T &lt;sub&gt;2&lt;/sub&gt; mapping sequence. Primary endpoint was the analysis of quantitative T &lt;sub&gt;2&lt;/sub&gt; values and contrast differences/ratios (CD/CR) between PCa and benign tissue. Secondary objectives were the correlation between T &lt;sub&gt;2&lt;/sub&gt; values, ISUP grade, apparent diffusion coefficient (ADC) value, and PI-RADS, and the evaluation of thresholds for differentiating PCa and clinically significant PCa (csPCa). Mann-Whitney test, Spearman's rank (r &lt;sub&gt;s&lt;/sub&gt; ) correlation, receiver operating curves, Youden's index (J), and AUC were performed. Statistical significance was defined as P &lt; 0.05. Median quantitative T &lt;sub&gt;2&lt;/sub&gt; values were significantly lower for PCa in PZ (85 msec) and PCa in TZ (75 msec) compared to benign PZ (141 msec) or TZ (97 msec) (P &lt; 0.001). CD/CR between PCa and benign PZ (51.2/1.77), respectively TZ (19.8/1.29), differed significantly (P &lt; 0.001). The best T &lt;sub&gt;2&lt;/sub&gt; -mapping threshold for PCa/csPCa detection was for TZ 81/86 msec (J = 0.929/1.0), and for PZ 110 msec (J = 0.834/0.905). Quantitative T &lt;sub&gt;2&lt;/sub&gt; values of PCa did not correlate significantly with the ISUP grade (r &lt;sub&gt;s&lt;/sub&gt; = 0.186; P = 0.226), ADC value (r &lt;sub&gt;s&lt;/sub&gt; = 0.138; P = 0.372), or PI-RADS (r &lt;sub&gt;s&lt;/sub&gt; = 0.132; P = 0.392). Quantitative T &lt;sub&gt;2&lt;/sub&gt; values could differentiate PCa in TZ and PZ and might support standardization of mpMRI of the prostate. Different thresholds seem to apply for PZ and TZ lesions. However, in the present study quantitative T &lt;sub&gt;2&lt;/sub&gt; values were not able to indicate PCa aggressiveness. 2 TECHNICAL EFFICACY: Stage 2

    Multilocus genotyping reveals new molecular markers for differentiating distinct genetic lineages among “candidatus phytoplasma solani” strains associated with grapevine bois noir

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    Grapevine Bois noir (BN) is associated with infection by “Candidatus Phytoplasma solani” (CaPsol). In this study, an array of CaPsol strains was identified from 142 symptomatic grapevines in vineyards of northern, central, and southern Italy and North Macedonia. Molecular typing of the CaPsol strains was carried out by analysis of genes encoding 16S rRNA and translation elongation factor EF-Tu, as well as eight other previously uncharacterized genomic fragments. Strains of tuf-type a and b were found to be differentially distributed in the examined geographic regions in correlation with the prevalence of nettle and bindweed. Two sequence variants were identified in each of the four genomic segments harboring hlyC, cbiQ-glyA, trxA-truB-rsuA, and rplS-tyrS-csdB, respectively. Fifteen CaPsol lineages were identified based on distinct combinations of sequence variations within these genetic loci. Each CaPsol lineage exhibited a unique collective restriction fragment length polymorphism (RFLP) pattern and differed from each other in geographic distribution, probably in relation to the diverse ecological complexity of vineyards and their surroundings. This RFLP-based typing method could be a useful tool for investigating the ecology of CaPsol and the epidemiology of its associated diseases. Phylogenetic analyses highlighted that the sequence variants of the gene hlyC, which encodes a hemolysin III-like protein, separated into two clusters consistent with the separation of two distinct lineages on the basis of tufB gene sequences. Alignments of deduced full protein sequences of elongation factor-Tu (tufB gene) and hemolysin III-like protein (hlyC gene) revealed the presence of critical amino acid substitutions distinguishing CaPsol strains of tuf-type a and b. Findings from the present study provide new insights into the genetic diversity and ecology of CaPsol populations in vineyards

    Linking Human Diseases to Animal Models Using Ontology-Based Phenotype Annotation

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    A novel method for quantifying the similarity between phenotypes by the use of ontologies can be used to search for candidate genes, pathway members, and human disease models on the basis of phenotypes alone

    Search for solar axions: CAST

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    The CERN Axion Solar Telescope (CAST) is searching for axions produced in the Sun's core by the Primakoff process. CAST is using a decommissioned Large Hadron Collider (LHC) test magnet where axions could be converted back into X-rays with energies up to 10 keV. Analysis of the 2003 data showed no signal above background implying an upper limit for the axion-photon coupling constant gagg < 1.16 X 10 ^-10 GeV exp -1 at 95% C.L. for ma . 0.02 eV [1]. The higher quality 2004 data is presently under analysis. CAST Phase II is scheduled to start in late 2005. This will be the first step in extending CAST's sensitivity to axion rest masses up to ~ 1 eV

    An Essential Role for Katanin p80 and Microtubule Severing in Male Gamete Production

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    Katanin is an evolutionarily conserved microtubule-severing complex implicated in multiple aspects of microtubule dynamics. Katanin consists of a p60 severing enzyme and a p80 regulatory subunit. The p80 subunit is thought to regulate complex targeting and severing activity, but its precise role remains elusive. In lower-order species, the katanin complex has been shown to modulate mitotic and female meiotic spindle dynamics and flagella development. The in vivo function of katanin p80 in mammals is unknown. Here we show that katanin p80 is essential for male fertility. Specifically, through an analysis of a mouse loss-of-function allele (the Taily line), we demonstrate that katanin p80, most likely in association with p60, has an essential role in male meiotic spindle assembly and dissolution and the removal of midbody microtubules and, thus, cytokinesis. Katanin p80 also controls the formation, function, and dissolution of a microtubule structure intimately involved in defining sperm head shaping and sperm tail formation, the manchette, and plays a role in the formation of axoneme microtubules. Perturbed katanin p80 function, as evidenced in the Taily mouse, results in male sterility characterized by decreased sperm production, sperm with abnormal head shape, and a virtual absence of progressive motility. Collectively these data demonstrate that katanin p80 serves an essential and evolutionarily conserved role in several aspects of male germ cell development
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