40 research outputs found

    Non-identical smoothing operators for estimating time-frequency interdependence in electrophysiological recordings

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    Synchronization of neural activity from distant parts of the brain is crucial for the coordination of cognitive activities. Because neural synchronization varies both in time and frequency, time–frequency (T-F) coherence is commonly employed to assess interdependences in electrophysiological recordings. T-F coherence entails smoothing the cross and power spectra to ensure statistical consistency of the estimate, which reduces its T-F resolution. This trade-off has been described in detail when the cross and power spectra are smoothed using identical smoothing operators, which may yield spurious coherent frequencies. In this article, we examine the use of non-identical smoothing operators for the estimation of T-F interdependence, i.e., phase synchronization is characterized by phase locking between signals captured by the cross spectrum and we may hence improve the trade-off by selectively smoothing the auto spectra. We first show that the frequency marginal density of the present estimate is bound within [0,1] when using non-identical smoothing operators. An analytic calculation of the bias and variance of present estimators is performed and compared with the bias and variance of standard T-F coherence using Monte Carlo simulations. We then test the use of non-identical smoothing operators on simulated data, whose T-F properties are known through construction. Finally, we analyze empirical data from eyes-closed surface electroencephalography recorded in human subjects to investigate alpha-band synchronization. These analyses show that selectively smoothing the auto spectra reduces the bias of the estimator and may improve the detection of T-F interdependence in electrophysiological data at high temporal resolution

    Impact of Smoking Exposure on Pregnancy and Perinatal Outcome Among Saudi Women: A Cross-Sectional Study

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    Objective: To assess the impact of smoking exposure on pregnancy and perinatal outcomes among Saudi women. Methods: This research will employ a cross-sectional study design to assess the impact of smoking exposure on pregnancy and perinatal outcomes among Saudi women. Cross-sectional studies are particularly suitable for examining associations and prevalence within a defined population at a specific point in time. In this case, the study aims to collect data on smoking behavior, pregnancy history, and perinatal outcomes among a representative sample of Saudi women in healthcare facilities across different regions of the country. The cross-sectional design allows for the efficient collection of data from a diverse population, providing insights into the relationship between smoking and perinatal outcomes without the need for long-term follow-up. Results: The study included 450 participants. The most frequent age among them was 35 and more years (n= 309, 68.7%) followed by 30-34 (n= 94, 20.9%). The most frequent educational level among study participants was the university (n= 408, 90.7%) followed by the school (n= 39, 8.7%). The most frequent job among study participants was a Governmental job (n= 159, 35.3%) followed by a housewife (n= 135, 30%). Number of previous births among study participants with most of them having a previous birth (n= 396, 88%) followed by this is the first birth (n= 54, 12%). Number of previous pregnancies among study participants with most of them having a previous pregnancy (n= 408, 90.7%) followed by this is the first pregnancy (n= 42, 9.3%). Number of abortions among study participants with most of them nothing (n= 234, 52%) followed by there is (n= 216, 48%). Participants were asked about smoking. The most frequent were don’t smoke (n= 315, 70%) followed by smoking (n= 135, 30%). The most frequent exposure to smoking among them was yes (n= 333, 74%) followed by no (n= 117, 26%). Conclusion: Study results showed that most of the study participants are the university according to their educational level. Most frequencies of participants had a previous birth. Most of them don’t smoke in another hand most of them were exposed to smoking. In addition, most of the study participants had good social connection

    Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

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    A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

    Author Correction: An analysis-ready and quality controlled resource for pediatric brain white-matter research

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    Enhanced high-open circuit voltage in fluorinated benzoselenadiazole-based polymer solar cells

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    Three new donor-acceptor copolymers (PCDTBSe, PCDTFBSe, and PCDTDFBSe) were designed and synthesized with 2,7-carbazole as the donor (D) unit and benzoselenadiazole (BSe), monofluoro-benzoselenadiazole, and difluoro-benzoselenadiazole as the acceptor (A) units, respectively. The structure-property relationship of these polymers was elucidated in bulk heterojunction polymer solar cells. All the polymers were fully characterized and exhibited good thermal stability and broad absorption. The highest occupied molecular orbitals (HOMOs) of the PCDTBSe (-5.29 eV), PCDTFBSe (-5.32 eV), and PCDTDFBSe (-5.35 eV) were decreased by incorporating fluorine atoms on the polymer backbone. The low-lying HOMO energy level suggested that the polymers would exhibit high open circuit voltage (V-OC) when blended with fullerene as the electron acceptor. Solar cell based on PCDTFBSe displayed a power conversion efficiency of 1.09% with a short-circuit current density (J(SC)) of 4.29 mA cm(-2), a V-OC of 0.78 V, and a fill factor (FF) of 32.51%, under the illumination of AM1.5G, 100 mW cm(-2)

    The Interplay of the Global Atherosclerotic Cardiovascular Disease Risk Scoring and Cardiorespiratory Fitness for the Prediction of All-Cause Mortality and Myocardial Infarction: The Henry Ford ExercIse Testing Project (The FIT Project)

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    Cardiorespiratory fitness (CRF) is inversely associated with atherosclerotic cardiovascular disease (ASCVD) risk. It is unclear whether the prognostic value of CRF differs by baseline estimated ASCVD risk. We studied a retrospective cohort of patients without known heart failure or myocardial infarction (MI) who underwent treadmill stress testing. CRF was measured by metabolic equivalents of task (METs) and ASCVD risk was calculated using the Pooled Cohorts Equations. Multivariable-adjusted Cox regressions analyses examined the association between METs and incident all-cause mortality and MI outcomes stratified by baseline ASCVD risk. The C-index evaluated risk discrimination while net reclassification improvement evaluated reclassification with CRF added to the ASCVD risk score. Our study population consisted of 57,999 patients of mean age 53 (13) years, 49% women, 64% white, 29% black. Over a median follow-up 11 years (interquartile range 8 to 14 years) there were 6,670 (11%) deaths, while there were 1,757 (3.0%) MIs over a median follow-up of 6 years (interquartile range 3 to 8 years). Among patients with ASCVD risk \u3e/=20%, those with METs \u3e/=12 had a 77% lower risk of all-cause mortality (Hazard ratio 0.23 95% confidence interval=0.20, 0.27) and 67% lower risk of MI (Hazard ratio 0.33 95% confidence interval=0.24, 0.46) compared to METs \u3c6. Similar results were obtained for those with ASCVD risk \u3c5%. Addition of METs to ASCVD risk score improved the C-statistic from 0.778 to 0.798 for all-cause mortality and 0.726 to 0.733 for MI (both p \u3c0.001). Addition of METs to ASCVD risk score significantly reclassified risk of all-cause mortality (p \u3c0.001) but not MI (p=0.052). In conclusion, CRF is inversely associated with risk of all-cause mortality and MI at all levels of ASCVD risk, and provides incremental risk discrimination and reclassification beyond the ASCVD risk score
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