295 research outputs found
First principles calculations of electronic and optical properties for mixed perovskites: Ba (1-x) Ca (x) TiO 3 and Ba (1-x) Sr (x) TiO 3 (x=0.4, 0.6)
International audienceThe effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba1-xCaxTiO3 and Ba1-xSrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase with Ca and Sr concentrations. The total and partial densities of states were analyzed to examine the contribution of different orbitals to the maximum of valence band and the minimum of the conduction band. The optical properties such as reflectivity, energy loss, refractive index and extinction coefficient were studied
A survey of IoT security based on a layered architecture of sensing and data analysis
The Internet of Things (IoT) is leading today’s digital transformation. Relying on a combination of technologies, protocols, and devices such as wireless sensors and newly developed wearable and implanted sensors, IoT is changing every aspect of daily life, especially recent applications in digital healthcare. IoT incorporates various kinds of hardware, communication protocols, and services. This IoT diversity can be viewed as a double-edged sword that provides comfort to users but can lead also to a large number of security threats and attacks. In this survey paper, a new compacted and optimized architecture for IoT is proposed based on five layers. Likewise, we propose a new classification of security threats and attacks based on new IoT architecture. The IoT architecture involves a physical perception layer, a network and protocol layer, a transport layer, an application layer, and a data and cloud services layer. First, the physical sensing layer incorporates the basic hardware used by IoT. Second, we highlight the various network and protocol technologies employed by IoT, and review the security threats and solutions. Transport protocols are exhibited and the security threats against them are discussed while providing common solutions. Then, the application layer involves application protocols and lightweight encryption algorithms for IoT. Finally, in the data and cloud services layer, the main important security features of IoT cloud platforms are addressed, involving confidentiality, integrity, authorization, authentication, and encryption protocols. The paper is concluded by presenting the open research issues and future directions towards securing IoT, including the lack of standardized lightweight encryption algorithms, the use of machine-learning algorithms to enhance security and the related challenges, the use of Blockchain to address security challenges in IoT, and the implications of IoT deployment in 5G and beyond
Measuring the Effect of Healthcare Service Quality Dimensions on Patient’s Satisfaction in The Algerian Private Sector
There is a gap in marketing literature related to impact of service quality dimensions on perceived service quality and patient satisfaction, in the private healthcare industry. The healthcare system is responsible for improving the general population’s health in a country. To differentiate from competitors, the quality of service is mainly considered a critical success factor for hospitals (Azmit et al., 2017). Therefore, competition is essential for improving quality and patient satisfaction in healthcare institutions (Kitapci et al., 2014). This article aims to determine the relationship between health service quality dimensions and patient satisfaction in the healthcare sector. Specifically, the paper seeks to find out the most critical dimensions of service quality, which is used to evaluate the characteristics of private healthcare service quality as perceived by patients. A field study was carried out on a sample of 208 patients in Tlemcen city in Algeria. The questionnaire developed for this study was based on a SERVQUAL model specifically, based on Parasuraman, Zeithaml, and Berry, (1985) variables that identified the influence of five dimensions (i.e., reliability, tangibility, assurance, responsibility, and empathy) in healthcare service environments on patient satisfaction. The results have found after the application of structural equation modelling that: reliability, tangibility, assurance, responsibility was more significant in contributing to patient satisfaction, while empathy was not significant. This indicates that patients tend to have a positive perception about the health service if they consider the perceived quality of the health service to be credible, reliable, tangible, and responsive, even though they may feel that the health provider does not empathize with them. Hence, healthcare industry practitioners can consider this model as an instrument to assess healthcare and help improve their service quality. Therefore, service provider managers can use this instrument to assess private hospital service quality in Algeria and other African countries
Dietary fat intake as a risk factor for the development of diabetes. Multinational, multicenter study of the Mediterranean Group for the Study of Diabetes (MGDS)
In the context of the Multinational MGSD Nutrition Study, three groups of subjects were studied: 204 subjects with recently diagnosed diabetes(RDM),42subjectswithundiagnoseddiabetes(UDM)(AmericanDiabetesAssociation criteria—fasting plasma glucose [FPG] 126 mg/dl), and 55 subjects with impaired fasting glucose(IFG)(FPG 110and126mg/dl).Eachgroupwascomparedwithacontrolgroupof nondiabetic subjects, matched one by one for center, sex, age, and BMI. Nutritional habits were evaluated by a dietary history method, validated against the 3-day diet diary. In RDM, the questionnaire referred to the nutritional habits before the diagnosis of diabetes. Demographic data were collected, and anthropometrical and biochemical measurements were taken. RESULTS— Compared with control subjects, RDM more frequently had a family history of diabetes(49.0vs.14.2%;P0.001),exercisedless(exerciseindex53.5vs.64.4;P0.01),and more frequently had sedentary professions (47.5 vs. 27.4%; P 0.001). Carbohydrates contributed less to their energy intake (53.5 vs. 55.1%; P 0.05), whereas total fat (30.2 0.5 vs. 27.8 0.5%; P 0.001) and animal fat (12.2 0.3 vs. 10.8 0.3%; P 0.01) contributed moreandtheplant-to-animalfatratiowaslower(1.50.1vs.1.80.1;P0.01).UDMmore frequentlyhadafamilyhistoryofdiabetes(38.1vs.19.0%;P0.05)andsedentaryprofessions (58.5vs.34.1%;P0.05),carbohydratescontributedlesstotheirenergyintake(47.61.7vs. 52.81.4%;P0.05),totalfat(34.71.5vs.30.41.2%;P0.05)andanimalfat(14.2 0.9 vs. 10.6 0.7%; P 0.05) contributed more, and the plant-to-animal fat ratio was lower (1.6 0.2 vs. 2.3 0.4; P 0.05). IFG differed only in the prevalence of family history of diabetes (32.7 vs. 16.4%; P 0.05). CONCLUSIONS— Our data support the view that increased animal fat intake is associated with the presence of diabetes
Analyzing Risk Factors for Brain Damages in a Group of Newborns with High Risk of Neurodevelopmental Sequelae: A Moroccan Study
Abstract The aim of the study is to identify risk factors for occurrence of perinatal brain injury objectified in transfontanellar ultrasound (TFU) in a group of infants with high risk of neurodevelopmental sequelae. It’s a retrospective study, conducted at the neonatal intensive care unit of the Children's Hospital of Rabat, during the period from 1 January to 31 December 2014. Were included newborns hospitalized for a medical condition with intrauterine croissance retardation (ICUR) more than 5 days and have survived. The neurological workup includes TFU made between day 2 and day 5 of life. Data analysis was performed on SPSS 18.0 software. The level of significance was p <0.05. The percentage of newborns that developed neurological damage to the TFU was 36%. Patients with abnormalities in the TFU had a breakdown time, duration dependence of O2, duration of hospitalization and a higher frequency of nosocomial infections than patients without abnormality. The interest in the prevention of nosocomial infections is to try to shorten the duration of invasive ventilation, favoring fast relay noninvasive ventilation. Keywords: brain injury; newborns; prematurity, neurodevelopmental sequelae, trans-fontanellar ultrasound.
Page number not for citation purposes 1 Des Furoncles résistants aux antibiotiques: penser à la myiase !!
Les myiases sont des infections parasitaires par des larves de mouches. La localisation cutanée doit être évoquée de retour d'un pays tropical devant une évolution inhabituelle de lésions cutanées. Nous rapportons une observation d'un militaire tunisien, ayant séjourné en République Démocratique du Congo. Il était atteint de myiase cutanée simulatrice d'une furonculose résistante aux antibiotiques. L'intérêt de cette observation est de souligner l'importance d'évoquer la myiase dont le traitement est simple et rapide chez un patient de retour de zone d'endémie.Key words: Furoncles, myiase, mouche
Evolution of iron speciation during hydration of C4 AF
International audienceIt is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C(4)AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixation of pollutant. In cement sorption isotherms, indicated that various metals can be retained by the C(4)AF hydrated products. Therefore the capabilities of those phase to retain heavy metal should not be neglected. Previous investigations have shown that the minerals formed during the hydration of C(4)AF are similar to those formed from C3A (pure tri-calcium aluminate) under comparable conditions. Nevertheless no investigation was conducted at the molecular level and there is still a controversy whether Fe substitutes for Al in the hydrated minerals in whole or in part, or if it forms FeOOH clusters scattered throughout the matrix. In this context we have conducted XAS experiments using synchrotron radiation. It was found that the hydration of C(4)AF forms C(3)AH(6) (hydrogarnet) in which Fe randomly substitutes for Al as well as an amorphous FeOOH phase. Intermediate products like AFm (i.e., an ill organized lamellar phase) are also formed but rapidly evolve to C(3)AH(6); iron does not seem to be incorporated in the AFm structure
Towards securing machine learning models against membership inference attacks
From fraud detection to speech recognition, including price prediction,
Machine Learning (ML) applications are manifold and can significantly improve
different areas. Nevertheless, machine learning models are vulnerable and are
exposed to different security and privacy attacks. Hence, these issues should be
addressed while using ML models to preserve the security and privacy of the data
used. There is a need to secure ML models, especially in the training phase to
preserve the privacy of the training datasets and to minimise the information
leakage. In this paper, we present an overview of ML threats and vulnerabilities,
and we highlight current progress in the research works proposing defence
techniques against ML security and privacy attacks. The relevant background for
the different attacks occurring in both the training and testing/inferring phases is
introduced before presenting a detailed overview of Membership Inference
Attacks (MIA) and the related countermeasures. In this paper, we introduce a
countermeasure against membership inference attacks (MIA) on Conventional
Neural Networks (CNN) based on dropout and L2 regularization. Through
experimental analysis, we demonstrate that this defence technique can mitigate the
risks of MIA attacks while ensuring an acceptable accuracy of the model. Indeed,
using CNN model training on two datasets CIFAR-10 and CIFAR-100, we
empirically verify the ability of our defence strategy to decrease the impact of MIA
on our model and we compare results of five different classifiers. Moreover, we
present a solution to achieve a trade-off between the performance of the model and
the mitigation of MIA attack
La chimiothérapie dans les cancers du nasopharynx localement avancés et métastatiques : Etude rétrospective de 144 cas
Les carcinomes nasopharyngés sont les tumeurs de la tête et du cou les plus fréquents en Afrique du nord. Le traitement basé sur la radiothérapie associée ou non à la chimiothérapie a donné d’excellents résultats dans les formes localisées. Par contre, le pronostic des carcinomes nasopharyngés localement avancés et/ou métastatiques reste sombre malgré le rôle incontournable de la chimiothérapie dans leur prise en charge thérapeutique. L’objectif de notre travail est de décrire les aspects épidémiologiques , cliniques, thérapeutiques et pronostiques des carcinomes nasopharyngés chez 144 patients traités au service d’oncologie médicale du centre hospitalier Hassan II de Fès, et de préciser l’impact de la chimiothérapie néoadjuvante et palliative sur leur évolution à court et à long terme
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