43 research outputs found
Evaluar la vinculación de la seguridad y salud en el trabajo y el desempeño laboral de los empleadores Huayo - 2022
Este estudio se realizó para determinar la relación entre la seguridad y salud y el
desempeño laboral de los trabajadores de Huayo - 2022. Es un estudio de tipo no
experimental, con un diseño de modelo, describir, correlacionar. La
muestra incluye 26 trabajadores de la Municipalidad de Huayo. Se utilizaron
cuestionarios como método de recolección de datos. El dispositivo ha sido validado
en opinión de tres expertos. Para el procesamiento de la información se utilizaron
las pruebas de correlación de Shapiro-Wilk y Rho Spearman.
Como resultado, se encontró que la variable seguridad y salud en el trabajo tiene
una correlación negativa muy alta y significativa con la variable del impacto del
cambio climático, Shapiro-Wilk, 0.777, con una significancia bidireccional de 0.001,
1% menor que la significancia estándar (P < 0,01). Además, se identificaron
correlaciones fuertes y excelentes para una mayor seguridad y salud en el trabajo y
una mayor eficiencia en el trabajo. en la zona de Huayo
AIDX: Adaptive Inference Scheme to Mitigate State-Drift in Memristive VMM Accelerators
An adaptive inference method for crossbar (AIDX) is presented based on an
optimization scheme for adjusting the duration and amplitude of input voltage
pulses. AIDX minimizes the long-term effects of memristance drift on artificial
neural network accuracy. The sub-threshold behavior of memristor has been
modeled and verified by comparing with fabricated device data. The proposed
method has been evaluated by testing on different network structures and
applications, e.g., image reconstruction and classification tasks. The results
showed an average of 60% improvement in convolutional neural network (CNN)
performance on CIFAR10 dataset after 10000 inference operations as well as
78.6% error reduction in image reconstruction.Comment: This paper is submitted to IEEE Transactions Circuits and Systems II:
Express Brief
Hardware-aware Training Techniques for Improving Robustness of Ex-Situ Neural Network Transfer onto Passive TiO2 ReRAM Crossbars
Passive resistive random access memory (ReRAM) crossbar arrays, a promising
emerging technology used for analog matrix-vector multiplications, are far
superior to their active (1T1R) counterparts in terms of the integration
density. However, current transfers of neural network weights into the
conductance state of the memory devices in the crossbar architecture are
accompanied by significant losses in precision due to hardware variabilities
such as sneak path currents, biasing scheme effects and conductance tuning
imprecision. In this work, training approaches that adapt techniques such as
dropout, the reparametrization trick and regularization to TiO2 crossbar
variabilities are proposed in order to generate models that are better adapted
to their hardware transfers. The viability of this approach is demonstrated by
comparing the outputs and precision of the proposed hardware-aware network with
those of a regular fully connected network over a few thousand weight transfers
using the half moons dataset in a simulation based on experimental data. For
the neural network trained using the proposed hardware-aware method, 79.5% of
the test set's data points can be classified with an accuracy of 95% or higher,
while only 18.5% of the test set's data points can be classified with this
accuracy by the regularly trained neural network.Comment: 15 pages, 11 figure
Polygenic Risk Scores for Prediction of Breast Cancer and Breast Cancer Subtypes
Stratification of women according to their risk of breast cancer based on polygenic risk scores (PRSs) could improve screening and prevention strategies. Our aim was to develop PRSs, optimized for prediction of estrogen receptor (ER)-specific disease, from the largest available genome-wide association dataset and to empirically validate the PRSs in prospective studies. The development dataset comprised 94,075 case subjects and 75,017 control subjects of European ancestry from 69 studies, divided into training and validation sets. Samples were genotyped using genome-wide arrays, and single-nucleotide polymorphisms (SNPs) were selected by stepwise regression or lasso penalized regression. The best performing PRSs were validated in an independent test set comprising 11,428 case subjects and 18,323 control subjects from 10 prospective studies and 190,040 women from UK Biobank (3,215 incident breast cancers). For the best PRSs (313 SNPs), the odds ratio for overall disease per 1 standard deviation in ten prospective studies was 1.61 (95%CI: 1.57-1.65) with area under receiver-operator curve (AUC) = 0.630 (95%CI: 0.628-0.651). The lifetime risk of overall breast cancer in the top centile of the PRSs was 32.6%. Compared with women in the middle quintile, those in the highest 1% of risk had 4.37- and 2.78-fold risks, and those in the lowest 1% of risk had 0.16- and 0.27-fold risks, of developing ER-positive and ER-negative disease, respectively. Goodness-of-fit tests indicated that this PRS was well calibrated and predicts disease risk accurately in the tails of the distribution. This PRS is a powerful and reliable predictor of breast cancer risk that may improve breast cancer prevention programs.NovartisEli Lilly and CompanyAstraZenecaAbbViePfizer UKCelgeneEisaiGenentechMerck Sharp and DohmeRocheCancer Research UKGovernment of CanadaArray BioPharmaGenome CanadaNational Institutes of HealthEuropean CommissionMinistère de l'Économie, de l’Innovation et des Exportations du QuébecSeventh Framework ProgrammeCanadian Institutes of Health Researc
Global burden of peripheral artery disease and its risk factors, 1990–2019 : a systematic analysis for the Global Burden of Disease Study 2019
peripheral artery disease were modelled using the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019 database. Prevalence, disability-adjusted life years (DALYs), and mortality estimates of peripheral artery disease were extracted from GBD 2019. Total DALYs and age-standardised DALY rate of peripheral artery disease attributed to modifiable risk factors were also assessed.
Findings
In 2019, the number of people aged 40 years and older with peripheral artery disease was 113 million (95% uncertainty interval [UI] 99·2–128·4), with a global prevalence of 1·52% (95% UI 1·33–1·72), of which 42·6% was in countries with low to middle Socio-demographic Index (SDI). The global prevalence of peripheral artery disease was higher in older people, (14·91% [12·41–17·87] in those aged 80–84 years), and was generally higher in females than in males. Globally, the total number of DALYs attributable to modifiable risk factors in 2019 accounted for 69·4% (64·2–74·3) of total peripheral artery disease DALYs. The prevalence of peripheral artery disease was highest in countries with high SDI and lowest in countries with low SDI, whereas DALY and mortality rates showed U-shaped curves, with the highest burden in the high and low SDI quintiles.
Interpretation
The total number of people with peripheral artery disease has increased globally from 1990 to 2019. Despite the lower prevalence of peripheral artery disease in males and low-income countries, these groups showed similar DALY rates to females and higher-income countries, highlighting disproportionate burden in these groups. Modifiable risk factors were responsible for around 70% of the global peripheral artery disease burden. Public measures could mitigate the burden of peripheral artery disease by modifying risk factors
Stroke genetics informs drug discovery and risk prediction across ancestries
Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries
Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Advanced X-ray characterization for the development of low consumption power transistors
Le CEA-Leti développe des composants de puissance à haut rendement énergétique à base de semi-conducteurs III-N (GaN, AlGaN, InGaN…), en particulier via un partenariat avec ST Microelectronics. Afin de minimiser les coûts et améliorer la compatibilité avec les standards de l’industrie microélectronique, le CEA-Leti a fait le choix d’élaborer des films minces de GaN hétéro-épitaxiés sur substrat de silicium. Cependant, ces deux matériaux présentent d’importants écarts de coefficient de dilation thermique et de paramètre de maille. Il en résulte des couches de GaN affectées par de forts gradients de contraintes mécaniques et de densité de dislocations dans leur épaisseur. Le niveau de performance des composants et la fragilité des plaques étant intimement lié à la qualité cristalline et à l’état de contrainte de ces films minces, il est important de disposer d’outils de métrologie performants, rapides et non destructifs. A ce titre, les travaux de cette thèse se concentrent sur l’étude de couches de GaN par diffraction de rayons X (DRX), technique reconnue et largement employée pour l’analyse de films épitaxiés. L’effet du gradient de contraintes sur les mesures de DRX est un élargissement asymétrique des pics de diffraction. Afin d’extraire ce gradient, nous suggérons de reproduire le signal de DRX expérimental par simulation de l’intensité diffractée par un cristal déformé. Une bonne adéquation entre simulations et mesures expérimentales est obtenue lorsque l’on modélise les variations locales du profil de déformation le long du plan de surface. Afin de quantifier les dislocations traversant les couches de GaN, nous proposons une méthodologie simple, basée sur la mesure du champ de micro-déformations entourant les dislocations. L’étude montre comment utiliser ce type de mesure dans les couches de GaN à fort gradient de contraintes. En outre, les résultats sont comparés aux densités de dislocations obtenues par des méthodes de caractérisation alternatives, telles que la microscopie électronique en transmission, la cathodoluminescence ou la DRX via l’analyse de la désorientation du réseau cristallin. Les études du gradient de contraintes et de la densité de dislocations, initialement menées sur des empilements complets de couches III-N, sont éclairées à l’aune de mesures en profondeur sur des films de GaN gravés progressivement.CEA-Leti develops power electronics components with high energy efficiency, based on semiconductors of the III-N group (GaN, AlGaN, InGaN…), in particular in partnership with ST microelectronics. In order to minimize the costs and improve the compatibility with the standards of microelectronics industry, CEA-Leti chose to produce epitaxial thin films of GaN grown on silicon substrates. However, these two materials have large mismatches of coefficient of thermal expansion and lattice parameter. The resulting GaN layers are affected by strong gradients of mechanical stress and dislocation density throughout their thickness. As component performances and wafer fragility are linked to crystalline quality and stress state of these thin films, it is important to have access to effective, rapid and non-destructive metrology tools. To this end, this PhD focuses on the study of GaN layers by X-ray diffraction (XRD), which is an acknowledged and widely used technique for the analysis of epitaxial films. The effect of stress gradient on XRD measurements is an asymmetrical broadening of diffraction peaks. We suggest extracting this gradient by reproducing the experimental XRD signal, by means of a simulation of the diffracted intensity stemming from a distorted crystal. A good agreement between simulations and measurements is obtained when modelling local variations of the strain profile throughout the surface plane. For the quantification of dislocations extending through the thickness of GaN layers, we suggest a simple methodology, based on the measurement of the micro-strain field surrounding the dislocations. The study shows how to use this type of measurement on GaN layers with strong stress gradient. In addition, the results are compared to the dislocation densities obtained with alternative characterization techniques such as transmission electron microscopy, cathodoluminescence or XRD, via an analysis of crystal lattice misorientations. The studies of stress gradient and dislocation density, initially carried out on complete stacks of III-N layers, are enlighten by means of in-depth measurements on progressively etched films of GaN