Surface scattering velocities in III-nitride quantum well laser structures via the emission of hybrid phonons

We have theoretically and numerically studied nitride-based quantum well (QW) laser structures. More specifically, we have used a QW made with III-nitride where the width of the barrier region is large relative to the electron mean free path, and we have calculated the electron surface capture velocities by considering an electron flux which is captured into the well region. The process is assisted by the emission of the longitudinal optical phonons as predicted by the hybrid (HB) model. The results of surface capture velocities via the emission of HB phonons are compared to the emission of the dielectric continuum phonons (Zakhleniuk et al 1999 Phys. Status Solidi a 176 79). Our investigation shows that the two different phonon models predict almost the same results for the non-retarded limit. Furthermore, the surface capture velocities strongly depend on the size of the structure and the heterostructure materials. Lastly, a comparison to the recent experimental values shows that our model could accurately describe the experimentally measured parameters of the quantum capture processes

Thrombotic Microangiopathy in Haematopoietic Cell Transplantation: an Update

Allogeneic hematopoietic cell transplantation (HCT) represents a vital procedure for patients with various hematologic conditions. Despite advances in the field, HCT carries significant morbidity and mortality. A rare but potentially devastating complication is transplantation-associated thrombotic microangiopathy (TA-TMA). In contrast to idiopathic TTP, whose etiology is attributed to deficient activity of ADAMTS13, (a member of the A Disintegrin And Metalloprotease with Thrombospondin 1 repeats family of metalloproteases), patients with TA-TMA have > 5% ADAMTS13 activity. Pathophysiologic mechanisms associated with TA-TMA, include loss of endothelial cell integrity induced by intensive conditioning regimens, immunosuppressive therapy, irradiation, infections and graft-versus-host (GVHD) disease. The reported incidence of TA-TMA ranges from 0.5% to 75%, reflecting the difficulty of accurate diagnosis in these patients. Two different groups have proposed consensus definitions for TA-TMA, yet they fail to distinguish the primary syndrome from secondary causes such as infections or medication exposure. Despite treatment, mortality rate in TA-TMA ranges between 60% to 90%. The treatment strategies for TA-TMA remain challenging. Calcineurin inhibitors should be discontinued and replaced with alternative immunosuppressive agents. Daclizumab, a humanized monoclonal anti-CD25 antibody, has shown promising results in the treatment of TA-TMA. Rituximab or the addition of defibrotide, have been reported to induce remission in this patient population. In general, plasma exchange is not recommended

National and firm-level drivers of the devolution of HRM decision making to line managers

Multinational companies must understand the influences on responsibility for managing people so that they can manage talent consistently thus ensuring that it is transferable across locations. We examine the impact of firm and national level characteristics on the devolution of HRM decision making to line managers. Our analysis draws on data from 2335 indigenous organizations in 21 countries. At the firm level, we found that where the HR function has higher power, devolution is less likely. At the national level, devolution of decision making to line management is more likely in societies with more stringent employment laws and lower power distance

Identity-Making Through Cree Mathematizing

We describe mathematics classroom teaching practice in an urban Canadian prairie Cree-bilingual school using the term Cree mathematizing, which, to us, means (re)considering Euro-Western school mathematics from the perspectives of the Cree people engaging with the content. Cree mathematizing takes the form of classroom lessons in which mathematical terms are translated between English and Cree, shared through stories situated in time, place, and relationships, and contextualized by the experiences of the students and teachers. In terms of the narrative conception of identity-making, Cree mathematizing is a process of engaging in school mathematics that necessitates Cree educators and students to understand themselves as producing mathematics through their unique experiences and stories, making Cree mathematizing a partial representation of identity. We argue that Cree mathematizing is a subversive practice that challenges the ways Euro-Western school mathematics is taught as a culture-free, apolitical, and decontextualized endeavour that is devoid of human narratives of experience.    Keywords: Indigenous mathematics education, Indigenization, narrative inquiry, Aboriginal educationLe terme « mathématisation crie » est utilisé pour décrire les pratiques éducatives en classe de mathématiques d’une école bilingue crie située en région urbaine des Prairies canadiennes. Pour nous, cela signifie de (re)considérer les cours de mathématiques eurooccidentaux de la perspective des peuples cris qui s’impliquent dans leur contenu. Dans la classe, la « mathématisation crie » est enseignée sous forme de leçons dans lesquelles les termes mathématiques sont traduits de l’anglais au cri ; elles sont transmises par des histoires situées dans le temps et le lieu, caractérisées par des relations, et contextualisées par les expériences des étudiants et des enseignants. En ce qui concerne la conception narrative de l’identité personnelle, la « mathématisation crie » s’articule par un processus d’engagement dans les mathématiques qui demande des éducateurs et étudiants cris de se comprendre eux-mêmes en tant que producteurs de mathématiques influencés chacun par ses propres expériences et son histoire, faisant de celles-ci une représentation partielle de leur identité. Nous soutenons que la « mathématisation crie » est une pratique subversive remettant en question la manière euro-occidentale—sans référence culturelle, apolitique, décontextualisée et dépourvue de récits d’expériences humaines—d’enseigner les mathématiques.   Mots-clés : éducation autochtone en mathématiques, autochtonisation, recherche narrative,éducation des Autochtone

Les mathématiques à l’école et miyō-pimōhtēwin

We want mathematics to be a process of miyō-pimōhtēwin (walking in a good way). Using a narrative inquiry methodology, we share our experiences working alongside two Cree elementary school teachers and the students in their mathematics classroom. The teachers taught principles that balance kohtawān (our spiritual being) and make curriculum into a relational space. The principles invite school mathematics to be learned and taught in a way that foregrounds self-awareness, doing things properly, learning new ways, being thankful, being humble, leaving problems behind you, helping yourself and keeping trying. This paper also demonstrates a promising practice of Indigenization in the mathematics classroom by providing a contextual way in which Cree students and teachers engaged in school mathematics in relational ways.Nous voulons que les mathématiques soient un processus de miyō-pimōhtēwin (marcher dans la bonne direction). S’appuyant sur une méthodologie d’enquête narrative, nous partageons nos expériences de travail aux côtés de deux enseignants cris de l'école primaire et des élèves dans leur classe de mathématiques.. Les enseignants ont dispensé des principes qui équilibrent kohtawān (notre bien-être spirituel) et font du programme scolaire un espace relationnel. Ces principes invitent à apprendre et à enseigner les mathématiques scolaires d'une manière qui met l'accent sur la conscience de soi, le fait de faire les choses correctement, d'apprendre de nouvelles façons, d'être reconnaissant, d'être humble, de laisser les problèmes derrière soi, de s'aider soi-même et de continuer à essayer. Cet article démontre également une pratique prometteuse d'autochtonisation dans la classe de mathématiques en fournissant une manière contextuelle dans laquelle les élèves cris et les enseignants sont engagés dans les mathématiques scolaires de manières relationnelles

Institutional duality and human resource management practice in foreign subsidiaries of multinationals

We examine how institutional context affects the decisions that subsidiaries of multinational corporations (MNCs) make in pursuing particular human resource management (HRM) practices in response to institutional duality. Drawing on Varieties of Capitalism, along with the concept of intermediate conformity, we argue that the use of particular HRM practices by MNC subsidiaries will differ depending on both the combination of home and host institutional contexts, and on the nature of the particular practice under consideration. Using data from a survey of HRM practices in 1196 firms across ten countries, we compare HRM practices in subsidiaries located and headquartered in different combinations of liberal and/or coordinated market economies. Our study suggests MNC subsidiaries conform only to the most persuasive norms, while exercising their agency to take advantage of the opportunities presented by institutional duality to adopt practices that distinguish them from indigenous competitors

High-Pressure Synthesis of a Pentazolate Salt

The pentazolates, the last all-nitrogen members of the azole series, have been notoriously elusive for the last hundred years despite enormous efforts to make these compounds in either gas or condensed phases. Here we report a successful synthesis of a solid state compound consisting of isolated pentazolate anions N5-, which is achieved by compressing and laser heating cesium azide (CsN3) mixed with N2 cryogenic liquid in a diamond anvil cell. The experiment was guided by theory, which predicted the transformation of the mixture at high pressures to a new compound, cesium pentazolate salt (CsN5). Electron transfer from Cs atoms to N5 rings enables both aromaticity in the pentazolates as well as ionic bonding in the CsN5 crystal. This work provides a critical insight into the role of extreme conditions in exploring unusual bonding routes that ultimately lead to the formation of novel high nitrogen content species

CRITERION, CONSTRUCT AND FACTORIAL VALIDITY OF THE GREEK VERSION OF THE INTERNATIONAL PHYSICAL ACTIVITY QUESTIONNAIRE-SHORT FORM (IPAQ-SF)

The current study investigated the validity of the Greek version of the International Physical Activity Questionnaire-short form (IPAQ-SF, seven days recall period, Craig et al., 2003). Specifically, criterion and construct validity were examined in a sample of 120 adults (M ± SD = 30.52 ± 14.87 years). In addition, factorial validity and internal consistency were examined in a second sample of 726 physically active adults (M ± SD = 38.80 ± 13.64 years). Further, associations were examined among the IPAQ-SF, exercise self-efficacy, body mass index and various socio-demographic variables. The statistical analyses indicated: (a) acceptable validity coefficients and factorial validity of the IPAQ, (b) acceptable internal consistency, (c) higher physical activity values in men compared to women and in athletes compared to non-athletes, (d) positive correlations between physical activity levels, exercise self-efficacy and past physical activity and (e) negative correlations among physical activity, age, number of children and body mass index. The Greek version of the IPAQ-SF was valid and therefore, could be useful for assessing physical activity.  Article visualizations