Size effect on magnetism of Fe thin films in Fe/Ir superlattices

In ferromagnetic thin films, the Curie temperature variation with the thickness is always considered as continuous when the thickness is varied from $n$ to $n+1$ atomic planes. We show that it is not the case for Fe in Fe/Ir superlattices. For an integer number of atomic planes, a unique magnetic transition is observed by susceptibility measurements, whereas two magnetic transitions are observed for fractional numbers of planes. This behavior is attributed to successive transitions of areas with $n$ and $n+1$ atomic planes, for which the $T_c$'s are not the same. Indeed, the magnetic correlation length is presumably shorter than the average size of the terraces. Monte carlo simulations are performed to support this explanation.Comment: LaTeX file with Revtex, 5 pages, 5 eps figures, to appear in Phys. Rev. Let

Cross-cultural comparison of mental illness stigma and help-seeking attitudes: a multinational population-based study from 16 Arab countries and 10,036 individuals

BackgroundThere is evidence that culture deeply affects beliefs about mental illnesses\u27 causes, treatment, and help-seeking. We aimed to explore and compare knowledge, attitudes toward mental illness and help-seeking, causal attributions, and help-seeking recommendations for mental illnesses across various Arab countries and investigate factors related to attitudes toward help-seeking.MethodsWe carried out a multinational cross-sectional study using online self-administered surveys in the Arabic language from June to November 2021 across 16 Arab countries among participants from the general public.ResultsMore than one in four individuals exhibited stigmatizing attitudes towards mental illness (26.5%), had poor knowledge (31.7%), and hold negative attitudes toward help-seeking (28.0%). ANOVA tests revealed a significant difference between countries regarding attitudes (F = 194.8, p \u3c .001), knowledge (F = 88.7, p \u3c .001), and help-seeking attitudes (F = 32.4, p \u3c .001). Three multivariate regression analysis models were performed for overall sample, as well as Palestinian and Sudanese samples that displayed the lowest and highest ATSPPH-SF scores, respectively. In the overall sample, being female, older, having higher knowledge and more positive attitudes toward mental illness, and endorsing biomedical and psychosocial causations were associated with more favorable help-seeking attitudes; whereas having a family psychiatric history and endorsing religious/supernatural causations were associated with more negative help-seeking attitudes. The same results have been found in the Palestinian sample, while only stigma dimensions helped predict help-seeking attitudes in Sudanese participants.ConclusionInterventions aiming at improving help-seeking attitudes and behaviors and promoting early access to care need to be culturally tailored, and congruent with public beliefs about mental illnesses and their causations

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

Global, regional, and national age-sex-specific mortality and life expectancy, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

Background: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. Methods: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. Findings: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. Interpretation: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

Physico-Chemical Characterization of Medical Solid Waste Leachate: Case of the Hospital de l'Amitié of Nouakchott, Mauritania

At the Hospital de l'Amitié, hospital waste corresponds to a mixture of waste assimilated to household waste and the waste from healthcare activities with infectious risks. In the context of hospital hygiene, the conducted study focuses on the impact of this hospital waste on the people of the Hospital de l'Amitié and the environment, and their handling of hospital waste (collection and transport). From an environmental point of view, the physico-chemical characterization of the leachate leaving submerged waste in three media (drinking water, distilled water and alcoholic distilled water) show high concentrations for most of the parameters studied. Physico-chemical characterization of solid waste from Hospital de l'Amitié in Nouakchott (Mauritania) was carried out from September to December 2020. The objective was to determine the value of 14 parameters (pH, temperature, turbidity, electrical conductivity, COD, BOD5, COD/BOD5, BOD5/COD, SS/BOD5, SS, nitrite, nitrate, sulfate and phosphorus), and improve the treatment method for this solid waste by immersing it in three different mediums (drinking water, distilled water and alcoholic distilled water). Among the 14 parameters, seven exceeded the Moroccan and WHO standards for medium 1, 2 and 3 respectively, conductivity (5340.00 μs/cm, 5820.00 μs/cm and 3550.00 μs/cm), BOD5 (122.00 mg/L, 106.00 mg/L and 142.00 mg/L), BOD5/COD (2.30, 1.93 and 2.88), SS (1000.00 mg/L, 600.00 mg/L and 600.00 mg/L), nitrite (0.91 mg/L, 25.00 mg/L and 45.00 mg/L), nitrate (210.00 mg/L, 200.00 mg/L and 110.00 mg/L) and sulfate (1000.00 mg/L, 2000.00 mg/L and 1000.00 mg/L). These results indicate the existence of toxic substances in these leachates that may impact the environment. In addition, the study proposes solid waste treatment from the Hospital de l'Amitié in Nouakchott (Mauritania) before its discharge into the natural environment. This observation is consolidated by the analyses carried out on the leachate of the waste immersed in three aqueous media (drinking water, distilled water and alcoholic distilled water)

Effects of substrate material on the electrical properties of self-assembled InAs quantum dots-based laser structures

In this work, the effects of the substrate material on the electrical properties of self-assembled InAs quantum dots (QDs)-based laser structures have been reported. Two InAs QD laser structures with the same active regions deposited on GaAs and Si substrates utilizing strain reducing layer (SRL) containing GaAs/InGaAs have been investigated using current–voltage (I–V), capacitance–voltage, and Deep-Level Transient Spectroscopy (DLTS) techniques. The I–V measurements illustrated that the rectification ratio (IF/IR) and built-in potential (ϕB) for the sample deposited on Si substrate are higher than that of sample deposited on GaAs substrate. However, the series resistance (Rs) of the InAs QDs deposited on Si substrate is lower than that of the InAs QDs deposited on GaAs substrate. The DLTS and Laplace-DLTS measurements showed that the number of traps in InAs QDs/GaAs devices is lower than that in InAs QDs/Si devices, corroborating with I–V results

Optical properties of self-assembled InAs quantum dots based P–I–N structures grown on GaAs and Si substrates by Molecular Beam Epitaxy

Extensive work on InAs quantum dots grown on GaAs substrates has been reported in the literature. However, research in the use of different substrate materials such as silicon to achieve an ideal and full integration of photonic and electronic systems is still a challenge. In this work we have investigated the effect of the substrate material (Si and GaAs) and strain reducing layer on the optical properties of InAs quantum dots for possible applications in laser devices grown by Molecular Beam Epitaxy. Two InAs quantum dots structures with similar active regions grown on GaAs and Si substrates using strain reducing layer consisting of InAs QDs/6 nm In0.15Ga0.85As have been investigated. Atomic Force Microscopy, Transmission Electron Microscopy, and photoluminescence have been used for the characterization of the samples. We have observed a red shift of the InAs QD photoluminescence peak energy for the sample grown on Si substrate as compared to the sample grown on GaAs substrate, which was associated with residual biaxial strain from the Si/GaAs heterointerface. This red-shift of the photoluminescence peak energy is accompanied by a broadening of the photoluminescence spectrum from ∼31 meV to a value of ∼46 meV. This broadening is attributed to the quantum dots size inhomogeneity increase for samples grown on Si substrate. This result open new insights for the controlling the emission of InAs quantum dots for photonic devices integration using Si substrates

Efficacy of chloroquine for the treatment of Plasmodium vivax in the Saharan zone in Mauritania

Background: In 2006, the Mauritanian Ministry of Health adopted a new therapeutic strategy based on the systematic use of artemisinin-based combination therapy (ACT), artesunate-amodiaquine and artemether-lumefantrine, for the first-and second-line treatment of uncomplicated malaria, respectively, regardless of Plasmodium spp. In the Saharan zone of the country, recent studies have shown that Plasmodium vivax largely predominates over Plasmodium falciparum. Anti-malarial drug response of P. vivax has not been evaluated in Mauritania. The aim of the present study was to evaluate the clinical efficacy and tolerance of chloroquine to treat P. vivax malaria in Mauritanian patients. Methods: Plasmodium vivax-infected patients aged > 6 months old were enrolled in Nouakchott and Atar in September-October 2013. Chloroquine was administered at the standard dose of 25 mg base/kg body weight over three days. Patients were followed until day 28, according to the standard 2009 World Health Organization protocol. Results: A total of 128 patients (67 in Nouakchott and 61 in Atar) were enrolled in the study. Seven patients (5.5%) were either excluded or lost to follow-up. Based on the per protocol analysis, chloroquine efficacy (adequate clinical and parasitological response) was 100%. Treatment was well-tolerated. One patient was excluded on day 1 due to urticaria and treated with artesunate-amodiaquine. Conclusions: Although the current national treatment guideline recommends artesunate-amodiaquine for the first-line treatment of uncomplicated malaria, including P. vivax malaria, chloroquine may still have an important role to play in anti-malarial chemotherapy in Mauritania. Further epidemiological studies are required to map the distribution of P. vivax and P. falciparum in the country

Estimation of air quality degradation due to Saharan dust at Nouakchott, Mauritania, from horizontal visibility data

It is now irrefutable that air pollution caused by large amounts of Total Suspended Particulates (TSP) and respiratory particulates or Particulate Matter less than 10 mu m in aerodynamic diameter (PM10) has numerous undesired consequences on human health. Air quality degradation far from the African continent, in the US and in Europe, caused by high concentrations of African dust, is seen as a major threat even though most of these countries are very distant from the Sahara. Surprisingly, no estimates of TSP or PM10 levels near the Saharan dust source are available. Based on horizontal visibility observations which are reduced by the presence of dust in the atmosphere, TSP and PM10 levels are estimated throughout the year 2000 at Nouakchott-Airport, Mauritania, using relations found in the literature. It appears that concentrations of particles are significant both in terms magnitude and frequency, as the 24-hour PM10 thresholds established by the US EPA National Ambient Air Quality Standards and the EU Limits Values for Air Quality were exceeded 86 and 137 times, respectively. The average annual concentration is far above air quality standards and estimated at 159 mu g m(-3) for TSP and 108 mu g m(-3) for PM10. These very high particulate levels are likely to represent an important public health hazard and should be considered as a major environmental risk