Étude du contact électromécanique Au−Ru/AlCu pour les MEMS RF ohmiques : modélisation, intégration et caractérisation

Aujourd'hui les systèmes de télécommunication sont le plus souvent construits à partir (i) d'électronique à l'état solide utilisant la technologie des semi-conducteurs telles les diodes PIN et les transistors FET ou (ii) de relais électromagnétiques. Chacune de ces technologies offre un compromis entre la fréquence d'opération, la linéarité, la capacité à transporter la puissance RF, les pertes d'insertion, l'isolation, le temps de commutation, la consommation électrique, la fiabilité, l'intégration à grande échelle, la masse et le coût. Par ailleurs, le besoin d'opérer à hautes fréquences est plus marqué avec l'arrivée de la 5G. Les MEMS RF sont à priori adaptés pour répondre aux nombreux défis des nouvelles générations de systèmes de télécommunication, cependant le principal obstacle reste leur fiabilité. Cette thèse s'inscrit dans un contexte d'amélioration des performances et de la fiabilité des micro-commutateurs MEMS RF à contact ohmique. L'encapsulation des MEMS RF aux niveau du wafer est nécessaire pour leur intégration dans des systèmes plus complets telles les matrices de commutations et les antennes configurables. En plus de permettre un contrôle de l'environnement directe du MEMS, la solution d'encapsulation ne doit pas altérer les performances RF du composant. La fiabilité du contact électromécanique est l'une des limitations majeures intrinsèques des MEMS RF ohmiques. Le contact Au-Ru/AlCu est proposé comme une configuration compatible avec un procédé MEMS intégrant une étape d'encapsulation au niveau du wafer par collage eutectique Al-Ge. L'utilisation d'un contact Au-Ru permet de réduire les forces d'adhésion et le transfert de matière en comparaison de l'utilisation d'une paire de contact symétrique de métaux nobles. Par ailleurs, l'empilement Ru/AlCu assure une résistivité totale proche de celle de l'AlCu tout en bénéficiant des propriétés avantageuses du Ru à l'interface de contact. Une étude fondamentale du contact électromécanique rugueux pour les applications MEMS RF a été conduite, et une méthodologie pour estimer la résistance électrique de contact en tenant compte de l'effet de la rugosité des surfaces a été développée. La fabrication d'un MEMS RF, sur une ligne de prototypage industriel 200 mm, encapsulé au niveau du wafer et intégrant le contact Au-Ru/AlCu a été réalisée avec succès. La solution proposée démontre un fort potentiel pour la fabrication d'une nouvelle génération de MEMS RF avec des performances accrues en comparaison des dispositifs actuellement sur le marché

Carbon risk management, carbon disclosure and stock market effects: an international perspective

This research investigates interrelations between carbon risk management, carbon disclosure, and two measures of stock market effects: the ex-ante cost of equity capital and market value. It is conducted based on a sample comprising the 500 largest global companies (G500) in 2009. Carbon risk management in this research is defined as the firm’s ability to estimate its historical and expected carbon intensity, identify potential carbon and climate change risks and associated opportunities, actions undertaken or planning to undertake to minimise risks and maximise opportunities, and the firm’s efficiency and effectiveness in managing these issues. Carbon disclosure is defined as set of quantitative and qualitative information that relates to a firm’s past and forecasted carbon emissions levels; its exposure to and financial implications of climate change associated risk and opportunities; and its past and future actions to manage these risks and opportunities. Three major contributions to the literature are made by this research. First, this study extends the literature on the relationship between environmental performance and disclosure by examining a specific and topical type of environmental performance and disclosure: carbon risk management and carbon disclosure. The results provide new evidence and support the prediction of economics-based disclosure theories (signalling and voluntary disclosure theories) that environmental disclosure is positively associated with environmental performance. Firms with superior carbon risk management tend to provide high quality and detailed disclosure about their carbon and climate change performance. When carbon risk management is controlled, these results reject the conjecture of socio-political theories (legitimacy and stakeholder theories) that inferior carbon risk performers provide more positive carbon disclosures. These results are further supported by intra-country and industry analyses as well as disaggregation of carbon risk management and disclosure into its components (sub-scores). The disaggregated scores analyses reveals the role of particular carbon risk management practices in enhancing disclosure quality about them. Firm’s historical carbon risk management as measured by its carbon emissions intensity is not associated with disclosure quality about the actual emissions and accounting standards to calculate them. In contrast, all other current and future carbon risk management strategies are positively associated with the disclosure quality about these strategies. This suggests that firms’ management are more likely to disclose high quality and credible information about their commitment to tackle climate change risks than their historical emissions since it reflects their historical emissions performance. These results, therefore, highlight the importance of partitioning carbon risk management and disclosure measurements to their components rather than relying on aggregated indices. Second, it develops comprehensive definitions and measurements for carbon risk management and disclosure. These new definitions and measurements tackle some shortcomings prevalent in prior research; thus, enhancing the rigour of results. Third, this research contributes to the debate about the economic consequences of environmental performance-disclosure activities by investigating the stock market effects of carbon risk management and carbon disclosure. This study fails to find a significant association between carbon risk management and disclosure and stock market indicators as expressed by the ex-ante cost of equity capital and market value. These results suggest that better carbon risk management and disclosure practices do not lower the ex-ante cost of equity capital or increase a firm’s market value. These results could be viewed in two ways. First, investors may not know how to interpret carbon risk management related information; thus they do not consider this information to be useful or they do not know how to value it. Second, investors are not interested in carbon risk management and disclosure activities or do not believe that engaging with such activities could lead to change in a firm’s reputation and competitive advantage or a reduction in risk. Hence, they do not make investment decisions on this basis. These results are robust to several additional analyses. Intra-industry and country analyses show similar results. Additionally, other tests are performed to check whether investors are interested in particular carbon risk management activities or disclosure categories such as historical emissions data or future carbon risk management strategies and activities. Once again, no association between stock market indicators and carbon risk management and disclosure categories is observed

Inheritance of Time of Flowering and Maturity and their Association with Other Agronomic Characters in Soybean (Glycine Max. (L.) Merrill)

Agronom

Automatic Verification of Key Management Architecture for Hierarchical Group Protocols

Emerging applications require secure group communications around hierarchical architecture protocols, like military or public emergency applications. However, conceiving such secure hierarchical protocols is not straightforward. Thus, their verification become a primordial issue in order to avoid the possible security attacks and vulnerabilities. Several attempts have been done to deal with formal verification of group protocols, but, in our knowledge, none of them has handled hierarchical ones. This paper investigates both specific challenges and security issues of hierarchical security group communications, and an overview of works done for their verification. We have chosen the Back-end Cl-AtSe of AVISPA tool, to verify an example of such protocols, as it enables to deal with the exponentiation of Diffie-Hellman often used in group key management

The Nrf2 Activator (DMF) and Covid-19: Is there a Possible Role?

COVID-19 is a new viral illness that can affect the lungs and airways with lethal consequences leading to the death of the patients. The ACE2 receptors were widely disturbed among body tissues such as lung, kidney, small intestine, heart, and others in different percent and considered a target for the nCOVID-19 virus. S-protein of the virus was binding to ACE2 receptors caused downregulation of endogenous anti-viral mediators, upregulation of NF-κB pathway, ROS and pro-apoptotic protein. Nrf2 was a transcription factor that's play a role in generation of anti-oxidant enzymes. To describe and establish role of Nrf2 activators for treatment COVID-19 positive patients. We used method of analysis of the published papers with described studies about COVID-19 connected with pharmacological issues and aspects which are included in global fighting against COVID-19 infection, and how using DMF (Nrf2 activator) in clinical trial for nCOVID-19 produce positive effects in patients for reduce lung alveolar cells damage. we are found that Nrf2 activators an important medication that's have a role in reduce viral pathogenesis via inhibit virus entry through induce SPLI gene expression as well as inhibit TRMPSS2, upregulation of ACE2 that's make a competition with the virus on binding site, induce gene expression of anti-viral mediators such as RIG-1 and INFs, induce anti-oxidant enzymes, also they have a role in inhibit NF-κB pathway, inhibit both apoptosis proteins and gene expression of TLRs. We are concluded that use DMF (Nrf2 activator) in clinical trial for nCOVID-19 positive patients to reduce lung alveolar cells damage. [Abstract copyright: © 2020 Saif M Hassan, Mahmood J Jawad, Salam W. Ahjel, Ram B. Singh, Jaipaul Singh4, Samir Mohamed Awad, Najah R Hadi.

Effects of alginates on the growth, haematological, immunity, antioxidant and pro-inflammatory responses of rabbits under high temperature

Heat stress (HS) is one of the most severe hurdles impacting rabbit growth, immunity, homeostasis, and productivity. Alginate oligosaccharides (AOS) have considerable beneficial effects due to their plausible antioxidant and immune-stimulatory properties. This work was planned to explore the preventive function of AOS as a new bio-feed additive against the harmful effects caused by environmental HS on growing rabbits. Rabbits were allotted in four experimental groups (25 animals in each group) and fed on a basal diet supplemented with 0.0 (AOS0), 50 (AOS50), 100 (AOS100), and 150 (AOS150) mg AOS/kg diet reared under summer conditions. Dietary AOS supplementation improved significantly (P ≤ 0.001) feed conversion rate, while both AOS100 and AOS150 significantly (P ≤ 0.001) enhanced the final body weight and body weight gain. All AOS addition significantly increased nitric oxide and lysosome activity and significantly reduced interferon-gamma (IFNγ) compared with those in the control group. Tumor necrosis factor α (TNFα), interleukin1β (IL-1β), myeloperoxidase and protein carbonyl levels were significantly reduced in rabbits fed diets containing AOS (100 and 150 mg/kg) compared with those in the control group under heat stress conditions. In addition, glutathione (GSH) and catalase (CAT) were significantly (P ≤ 0.001) improved with increasing AOS dietary levels compared with the control group. Still, total antioxidant capacity (TAC), malondialdehyde (MDA), hematocrit, mean corpuscular volume (MCV), eosinophils, and lymphocytes did not change. Erythrocyte's indices improved significantly (P ≤ 0.001), while neutrophils and white blood cell counts were decreased by dietary AOS inclusion. Immunological (IgM and IgG) were markedly reduced in AOS-treated groups compared with the control group. The current investigation exemplified that AOS as a novel bio-feed additive that could be an effective strategy to extenuate prejudicial effects in heat-stressed rabbits via enhancing immunity, and antioxidant defence system, further regulating the inflammation cytokines.Universidad King Saud, Riad, Arabia Saudita | Ref. RSP2023R439Universidade de Vigo/CISU

Studies on Arabic Dialectology and Sociolinguistics

This volume contains over fifty articles related to various fields of modern Arabic dialectology. All the articles are revised and enhanced versions of papers read on the 12th Conference of the Association Internationale de Dialectologie Arabe (AIDA) held in Marseille in June 2017. Since its first conference in Paris in 1993, AIDA members gather every two years in different country. The collection of the AIDA proceedings offer an updated insight of the development of the field. During the past few decadesthe the study of Arabic dialects has become an important branch of research covering a wide range of subjects from phonological analyses, morphosyntax, semantics to pragmatics, sociolinguistics, folk linguistics, studies on literacy and writings, cultural and artistic practices, etc. As many articles of this volume illustrate, the study of Arabic dialects explores different aspects of the languages and cultures of the contemporary Arab world. A remarkable feature is the growing and constant participation of young scholars from all around the globe

Accent modification as a raciolinguistic ideology: a commentary in response to Burda et al. (2022)

In this commentary, we collectively examine a recent article titled “Effectiveness of Intense Accent Modification Training with Refugees from Burma” by Burda et al. (2022). Whilst our response is aimed at revealing the theoretical and methodological shortcomings of Burda et al., it will also expose the raciolinguistic ideologies in accent modification and highlight the need for careful ethical considerations on vulnerable populations, such as refugees and asylum seekers

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