Search

Many of the known examples of half-metallic ferromagnets HMF are oxides, sulfides, or Heusler alloys have attracted some interest for their potential use in spintronics. In order to achieve such understanding we have performed an ab-initio calculations with spin polarization using plane-wave pseudo potential technique based on the density-functional theory (DFT), the exchange-correlation potential was treated with the generalized gradient approximation (PBE-GGA), whereas for the treatment of on-site electron-electron correlations the PBE-GGA+U approximation (where U is the Hubbard Coulomb energy term) are applied for the calculation of the structural, electronic, elastic and magnetic properties of Pd2PrX (X=Cl, F). The results showed that for Pd2PrCl and Pd2PrF, Hg2CuTi-type structure is energetically more stable than Cu2MnAl-type structure at the equilibrium volume. Electronically, Pd2PrCl and Pd2PrF exhibit half-metallicity with small band gaps of 0.06 and 0.25eV respectively with GGA-PBE+U in the spin-down channels whereas spin-up channels are conducting. The calculated total magnetic moment of 2.00 μB per formula unit is very close to integer value and agree well with the Slater-Pauling rules ( Mtot=34-Ztot), where the magnetic moment is basically carried by Pr atoms. However, the elastic properties show that Pd2PrX (X=Cl, F) compounds are ductile and anisotropic according to the analysis of B/G and Cauchy’s pressure. The Thermodynamic properties were also analyzed using the quasi-harmonic Debye model. Both the compounds are found structurally stable.

PurposeDespite the fast progress in structural health monitoring (SHM), the efficient use in practice of emerging techniques for large civil engineering structures is still a challenge. This paper outlines a practical framework to optimize both the number and the locations of sensors to measure frequency response functions (FRFs) that will be processed and used to predict the location and the damage level in a model of an existing suspension bridge.Design/methodology/approachSensors number and placement (SNPO) procedure is proposed and carried out on a 3D FE model of the 502 m long Oued Dib suspension bridge (Algeria) to determine the degrees of freedom (DOFs) that will receive the sensors. For this purpose, accessible candidate positions on the model are first determined and then reduced by taking the DOFs with the lowest values of the Fisher information matrix (FIM) associated with each of the DOFs taken individually. A genetic algorithm with an objective function equal to the square root of the sum of the squares of the non-diagonal elements of the MAC matrix and a mutation function that allows increasing and decreasing the number of the chromosomes (sensors) of the individuals showed stable convergence to optimal solutions. FRFs at sensor positions generated from the 3D FE model and altered with artificial noise to simulate experimental conditions have been used to constitute a database to train and test a feed-forward neural network.FindingsA framework for SHM integrating a genetic algorithm to optimize both the number and placement of the sensors on the structure.Research limitations/implicationsThe procedure can be applied only for single predefined/potential damage detection.Practical implicationsThe evidence from this study suggests that the proposed procedure provides a consistent framework to implement a SHM scheme for existing large infrastructures.Social implicationsVital infrastructures require special structural protection that can be achieved through effective SHM. This study contributes to the deployment of SHM for existing civil engineering structures.Originality/valueIn addition to the integrated SHM framework proposed in this study, the latter includes an efficient genetic algorithm capable to optimize both the number and the placement of the sensors.

Contexte : Il est devenu évident que la Covid-19 peut affecter non seulement les poumons, mais peut également conduire à des troubles multiorganes. Maintes publications scientifiques suggèrent que les pieds peuvent également être affectés par la maladie. Objectif et méthodes : En explorant les données de la littérature, cette revue offre un panorama des principaux troubles podiatriques associés à la Covid-19, tels qu’ils sont actuellement compris et répertoriés. Résultats : Les pathologies du pied associées à la Covid-19 se présentent sous forme de manifestations cutanées, vasculaires ou neuromusculaires. Les lésions cutanées sont dominées par les pseudoengelures ou le syndrome d’orteils Covid. Sur le plan vasculaire, on note des manifestations sévères parmi lesquelles l’ischémie périphérique qui entraîne une nécrose et une gangrène pouvant aboutir jusqu’à l’amputation. Le bilan neuromusculaire peut révéler un pied douloureux, un pied parétique, des troubles de la marche et de l’équilibre. Conclusion : Les pathologies du pied liées à la Covid-19 doivent être connues et identifiées afin d’être traitées. De plus, elles peuvent potentiellement fournir un indice utile aux cliniciens pour identifier la Covid-19 et guider la conduite pratique.

The term blackfishing, which takes a twist on the concept of catfishing, that is, tricking people online into thinking you are someone else, refers to the practice of (mostly) White women pretending to be Black by using makeup, hairstyles, and fashion that originate in Black Culture to gain financial benefits. This article aims to contextualize the concept of blackfishing through a critical literary review that will cover the following elements: cultural appropriation, the commodification of Black culture, the representation of Black women in North America, and the operationalization of blackfishing.

We have investigated the structural, electronic, magnetic, elastic and thermoelectric properties of the sp-based half-Heusler LiBaX (X = Si and Ge) alloys using the full-potential linearized augmented plane wave method of density functional theory. Two approaches are employed to approximate the correlation-exchange potential, namely the generalized-gradient approximation and the modified Becke–Johnson. Both compounds free of transition metals are ferromagnetic, half metallic with a large spin-flip gaps which are appropriate for Spintronic applications. Their half-metallicity is preserved under large lattice constant and pressure change which make them promising candidates for spintronic devices. The transport properties reveal high figure of merit values making these compounds great thermoelectric candidates. Moreover, the studied half-Heuslers are mechanically stable and both of them exhibit negative formation energy and cohesion which indicate the possibility of synthesizing and stabilizing these cheap and available materials. Up to date, no experimental or theoretical studies have been carried out regarding LiBaSi, while for LiBaGe, thermoelectric properties have not been investigated yet.

The region of Ouargla in the south-east of Algeria has many thermal hot springs that are still largely untapped. The aim of this pilot study is to assess the contribution of balneotherapy in the functional improvement of low back pain patients. Methods: This study concerned non-specific chronic low back pain patients treated at the balneotherapy and rehabilitation center in Ouargla, Algeria. The sample was divided into two groups for comparative purposes: the first one is the intervention group (A) receiving physical therapy combined with balneotherapy, and the second is the control group (B) receiving physical therapy alone. The response was assessed using the Oswestry Disability Index (ODI) in its Arabic version. The questionnaire was given at the beginning and end of treatment. An improvement in Oswestry is considered clinically relevant if it is above 30 %. The sensitivity to changes is estimated by the standardized response mean and effect size. Results: Ten patients meeting the eligibility criteria were split equally into the two groups. We observed that 60 % (3/5) patients had a clinically relevant improvement in Oswestry in group (A) versus 20 % (1/5) patient in group (B). The effect size for group (A) and group (B) is 1.20 and 0.71, respectively. The standardized response mean is 1.13 for group (A) versus 1.01 for group (B). Conclusion: The results of the present study reiterate that in addition to conventional rehabilitation, balneotherapy can be more effective in the treatment of patients suffering from non-specific chronic low back pain.

An ab initio theory has been applied to investigate the electronic, elastic, magnetic, and half-metallic behaviors of the newly designed quaternary Heusler compounds BaNYO (Y = K, Rb, and Cs) without 3d transition metal elements. However, elastic properties show that our compounds are ductile and anisotropic. The calculated results show that our compounds are half-metallic with an integer magnetic moment of 2.00μB at the equilibrium lattice parameter, with 100% spin polarization around the Fermi level, which follows the famous Slater–Pauling rule, Mtot = 16 − Zt, Mtot, is the total magnetic moment and Zt is the total number of valence electrons. Based on its equilibrium and strained lattice constants, the magnetic and half-metallic behaviors of this compound have been discussed in detail. Large half-metallic gaps of BaNYO (Y = K, Rb, and Cs) compounds of 0.95, 0.90, and 0.85 eV, respectively, have been found in our work, which is nearly larger than any previous study. Furthermore, the calculated negative formation energy and cohesive energy indicate that these two alloys have good chemical stability. This theoretical investigation provides further insight into the application of BaNYO compounds as spintronic materials.

Among older adults who have recently sustained a fracture, there is substantial adoption of mobile technology. Furthermore, health and eHealth literacy level reported by participants supports the development of interactive eHealth interventions toward fostering better patient engagement in skeletal health management. Electronic health resources are increasingly used in the self-management of medical conditions. We aimed to identify the current level of technology adoption, health, and eHealth literacy among older adults with a recent fracture, to determine if the use of electronic interventions would be feasible and acceptable in this population. Adults ≥ 50 years with recent fractures were invited to complete a self-administered survey composed of 21 questions, including an 8-item perceived eHealth literacy scale. A total of 401 participants completed the survey (women, 64%; ≥ 65 years, 59%; university education, 32%). Most participants reported no difficulty in reading printed health material (67%) and felt confident in filling out medical forms (65%). Younger age and higher levels of education were associated with higher health literacy. Most respondents (81%) owned at least one mobile device (smartphone, 49%; tablet, 45%). eHEALS scores were similar among men (29, IQR 24–32) and women (29, IQR 25–33), and between younger age group categories (50–64 years, 30; IQR 26–33; and 65–74 years, 29; IQR 25–32), but lower in the oldest age group (≥ 75 years, 24; IQR 21–29; p

Ensuring continuity in rehabilitation care in these difficult times is a real challenge. During this recent Covid-19 pandemic, physical medicine and rehabilitation (PMR) professionals are faced with many hazards in their daily practice, some of which are related to the risk of infection, which appears to be high in patients with PRD who are particularly vulnerable because of their state of health and their functional limitations. This unprecedented pandemic has imposed a radical change in the management and organization of PRM services, which has profoundly altered the practice of rehabilitation. In addition, the shortage of staff in terms of numbers and qualifications make MPR's response even more difficult in the face of Covid-19. Finally, other difficulties may arise depending on the stage of the disease. Despite all these challenges, rehabilitation professionals try to do their best to provide adequate care to their patients, adopting alternative strategies.

Resume La pandemie de Covid-19 a impose un changement soudain et force dans le spectre des soins de sante qui s’est produit avec une rapidite sans precedent. La necessite d’accommoder le changement a une grande echelle a exige de l’ingeniosite et une reflexion decisive. Ces changements affectent les acteurs du domaine de la medecine physique et de la readaptation (MPR) personnellement et professionnellement. Les experts reflechissent maintenant a la maniere d’ameliorer la pratique medicale en utilisant de nouvelles approches en readaptation. Les modeles et les experiences rapportes dans la litterature, tels que la telereadaptation, la preadaptation et l’activite physique adaptee sont bases sur la strategie de l’auto-reeducation collaborative qui est proposee comme un element-cle de ces voies alternatives. Ces approches innovantes aideront a restructurer les processus d’exercice de la readaptation, non seulement dans ces moments inhabituels, mais aussi dans l’avenir de la MPR. Niveau de preuve NA.

The structural, electronic, magnetic, elastic and thermoelectric properties of full-Heusler alloys Co2ZrZ (Z = Al, Si, Ga and Sn) are investigated using the augmented plane wave method (FP-LAPW) based on the framework of spin density functional theory. The term of the exchange and correlation potential (XC), is treated by the generalized gradient approximation GGA and Trans-Blaha-modified Becke–Johnson (TB-mBJ). The results obtained showed that the Cu2MnAl-type structure has more stable energy than the Hg2CuTi-type structure for all the full-Heusler studied. From electronic calculations, it is found that all the compounds studied have an indirect band gap with a half-metallic behavior. Furthermore, we also found that all materials have integral magnetic moments which are mainly due to 100% spin polarization at Fermi energy. The calculated elastic constants and the anisotropy shear factors indicate that these compounds have a ductile character and are mechanically stable. Finally, we calculated the thermoelectric properties by applying Boltzmann theory as implemented in the BoltzTraP code. The results obtained for the merit factor (ZT) and Seebeck coefficient (S) make these materials promising candidates in thermoelectric applications and in spintronics devices.

The structural, electronic and elastic properties of full-Heusler alloys Cs 2 CrGe are examined in this study using FP-LAPW method based on density functional theory. Results of our calculations predict that the Hg 2 CuTi-type structure is more stable than the Cu 2 MnAl-type structure and that the ground state of this alloy is ferromagnetic. The band structure of Cs 2 CrGe shows half metallic behavior for the two approaches GGA and mBJ-GGA with an indirect band gap. The total magnetic moment calculated is in good agreement with the Slater-Pauling rule for full-Heusler alloys with an important magnetic moment equal to 4 µ B . Elastic properties indicate that our compound is ductile, anisotropic and not too rigid.

Seismic site amplification studies are generally used to assess the effects of local geology and soil conditions on ground motion characteristics. Although extensive reviews on site amplification phenomena associated with stratigraphic effects can be found in the specialized literature, it should be pointed out that most of the practical applications have been limited to the study of vertically propagating shear horizontal (SH) waves, i.e., to the 1-D soil amplification problem. Furthermore, little attention, if any, has been devoted to the study of the effects of non-vertically incident SH waves on surface accelerograms and on the earthquake response of structures. In the present work, the study is extended to an investigation of 2-D site amplification of non-vertically propagating seismic shear waves in multilayered viscoelastic soil deposits. Sensitivity analyses of the effects of non-vertical incidence on site amplification functions are performed based on site geotechnical data collected from post-seismic investigations of the 1980 El-Asnam earthquake. Analytical results are discussed in terms of seismic site transfer functions, spectral ratios, surface acceleration time histories, and structural response spectra for different values of wave incidence angle. Both bedrock and rock outcropping cases are examined.