2,053 research outputs found

    Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

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    Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

    Post-traumatic stress disorder in youth exposed to the Syrian conflict: A systematic review and meta-analysis of prevalence and determinants

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    A decade of ongoing armed conflict in Syria has damaged the physical and mental health of millions of adults and children. This study aimed to systematically review the prevalence of post-traumatic stress disorder among youth exposed to the Syrian conflict, and understand its individual and contextual determinants. The screening procedure resulted in 26 studies, with a total of 11,400 Syrian children and adolescents. The prevalence was 36% (95% CI (0.29–0.43), p < 0.001). Loss of family members or acquaintances, witnessing violence, and social withdrawal increased the risk of post-traumatic stress disorder, while social trust and social support were protective factors. © The Author(s) 2022

    the case of Southern European elderly

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    Background: Inequalities in the distribution of self-reported health (SRH) have been widely reported. Its higher expressivity among women, elderly and least educated groups has been partly attributed to differences in their health perceptions. However, this subjectivity may be masking the burden of mental illness in these groups. Thus, we sought to understand if depression symptoms mediate inequalities in SRH. Methods: SHARE waves 4 and 6, pertaining to Spain, Italy and Portugal, were used (n2011 = 8517, n2015 = 11 046). Inequalities in SRH were calculated, comparing the risk amongst education level, gender and age groups, adjusting for chronic diseases, functional limitations and country fixed effects. We then tested depression symptoms as mediators. Results: Depression symptoms were associated with poor SRH (odds ratio (OR)2011 = 1.379, OR2015 = 1.384, P < 0.001). Their inclusion reduced the magnitude of the association between SRH and education, annulled the statistical significance for age, and reversed the gender effect. As expected, chronic diseases and functional limitations remained significant predictors of poor SRH. Conclusions: Depression symptoms, together with chronic diseases and functional limitations, explain the poorer SRH of the least educated, female and older groups in the Southern European population. Therefore, tackling inequalities in SRH must require focusing on mental health issues, which disproportionately affect the most vulnerable groups.publishe

    Combined genetic and epigenetic alterations of the TERT promoter affect clinical and biological behaviour of bladder cancer

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    In urothelial bladder cancer (UBC), risk stratification remains an important unmet need. Limitless self‐renewal, governed by TERT expression and telomerase activation, is crucial for cancer progression. Thus, telomerase activation through the interplay of mutations (TERTp^(Mut)) and epigenetic alterations in the TERT promoter may provide further insight into UBC behavior. Here, we investigated the combined effect of TERTp^(Mut) and the TERTHypermethylated Oncological Region (THOR) status on telomerase activation and patient outcome in a UBC international cohort (n=237). We verified that TERTp^(Mut) were frequent (76.8%) and present in all stages and grades of UBC. Hypermethylation of THOR was associated with higher TERT expression and higher‐risk disease in non‐muscle invasive bladder cancers (NMIBC). TERTp^(Mut) alone predicted disease recurrence (HR: 3.18, 95%CI 1.84 to 5.51, p<0.0001) but not progression in NMIBC. Combined THOR^(high)/TERTp^(Mut) increased the risk of disease recurrence (HR 5.12, p<0.0001) and progression (HR 3.92, p=0.025). Increased THOR hypermethylation doubled the risk of stage progression of both TERTp^(wt) and TERTp^(Mut) NMIBC. These results highlight that both mechanisms are common and coexist in bladder cancer and while TERTp^(Mut) is an early event in bladder carcinogenesis THOR hypermethylation is a dynamic process that contributes to disease progression. While the absence of alterations comprises an extremely indolent phenotype, the combined genetic and epigenetic alterations of TERT bring additional prognostic value in NMIBC and provide a novel insight into telomere biology in cancer

    Novel single nucleotide polymorphism-based assay for genotyping Mycobacterium avium subsp. paratuberculosis

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    Typing of Mycobacterium avium subspecies paratuberculosis strains presents a challenge, since they are genetically monomorphic and traditional molecular techniques have limited discriminatory power. The recent advances and availability of whole-genome sequencing have extended possibilities for the characterization of Mycobacterium avium subspecies paratuberculosis, and whole-genome sequencing can provide a phylogenetic context to facilitate global epidemiology studies. In this study, we developed a single nucleotide polymorphism (SNP) assay based on PCR and restriction enzyme digestion or sequencing of the amplified product. The SNP analysis was performed using genome sequence data from 133 Mycobacterium avium subspecies paratuberculosis isolates with different genotypes from 8 different host species and 17 distinct geographic regions around the world. A total of 28,402 SNPs were identified among all of the isolates. The minimum number of SNPs required to distinguish between all of the 133 genomes was 93 and between only the type C isolates was 41. To reduce the number of SNPs and PCRs required, we adopted an approach based on sequential detection of SNPs and a decision tree. By the analysis of 14 SNPs Mycobacterium avium subspecies paratuberculosis isolates can be characterized within 14 phylogenetic groups with a higher discriminatory power than mycobacterial interspersed repetitive unit–variable number tandem repeat assay and other typing methods. Continuous updating of genome sequences is needed in order to better characterize new phylogenetic groups and SNP profiles. The novel SNP assay is a discriminative, simple, reproducible method and requires only basic laboratory equipment for the large-scale global typing of Mycobacterium avium subspecies paratuberculosis isolates

    Gapped Excitations in the High-Pressure Antiferromagnetic Phase of URu2_2Si2_2

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    We report a neutron scattering study of the magnetic excitation spectrum in each of the three temperature and pressure driven phases of URu2_2Si2_2. We find qualitatively similar excitations throughout the (H0L) scattering plane in the hidden order and large moment phases, with no changes in the ω\hbar\omega-widths of the excitations at the Σ\Sigma = (1.407,0,0) and ZZ = (1,0,0) points, within our experimental resolution. There is, however, an increase in the gap at the Σ\Sigma point from 4.2(2) meV to 5.5(3) meV, consistent with other indicators of enhanced antiferromagnetism under pressure.Comment: 5 pages, 3 figures, 1 tabl
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