On homogeneous Hermite-Lorentz spaces

We define naturally Hermite-Lorentz metrics on almost-complex manifolds as special case of pseudo-Riemannian metrics compatible with the almost complex structure. We study their isometry groups

Foreign Direct Investment (FDI) and Governance: The Case of MENA

Is there a relationship between Foreign Direct Investment (FDI) and governance practiced in a given country? To answer this question we used the econometrics of panel data for the MENA region (11 countries) during the period 1996-2014. The results of the econometric estimation show seven variables that are statistically significant, namely the Gross Domestic Product (economic risk variable), the current account balance as% of GDP (economic risk variable), the domestic investment rate (economic risk variable), external debt (financial risk variable), the debt service as percentage of exports (financial risk variable), the functioning of the state (variable governance) and corruption (governance variable). While different parts of the world are competing to further attract FDI, countries in the MENA region need to conduct adequate policies oriented towards improving the business climate and good governance to benefit from these funding streams deemed less expensive

The Blockade Imposed on Qatar from the Perspective of International Treaties and Resulting Responsibilities

 لا شك أن صدور القرار المفاجئ لمجموعة الدول الأربع، السعودية والإمارات والبحرين ومصر، بمقاطعة دولة قطر وفرض نوعٍ من الحصار البري والبحري والجوي والدبلوماسي عليها، أثار قضايا عدّة تتعلّق بالعلاقات الدَّوليَّة وعلاقات الجوار والأعراف والتقاليد، وترتب عليه انتهاك الكثير من حقوق دولة قطر، الاقتصَاديَّة والاِجتمَاعيَّة والأمنية والسياسية وغيرها، أقرتها المواثيق الدولية والإقليمية. أوضحت الدراسة أن حالة دولة قطر تُعد حصارًا وليس مقاطعة طبقًا لدلالات الحصار في اللغة والفقه الدولي، وأن دول الحصار افتقرت إلى المرجعيات الدولية خاصة فيما تضمنه الفصل السابع من ميثاق منظمة الأمم المتحدة الذي أعطى مجلس الأمن وحده دون غيره سلطة إصدار أي قرار من هذا النوع بموجب المادة 41؛ يأمر فيه باتخاذ التدابير المناسبة ضدّ الدولة أو الدول المعتدية أو المهدّدة للسلم والأمن الدوليين، وبـوقف الصلات الاقتصَاديَّة والمواصلات الحديدية والبحرية والجوية والبريدية والبرقية واللاسلكية وغيرها من وسائل المواصلات وقفًا جزئيًّا أو كليًّا، وبقطع العلاقات الدبلوماسية. من ثم فإن حصار الدول الأربع لدولة قطر ينتهك ويخالف تمامًا قواعد القانون الدولي وكافة المواثيق الدولية وخاصة مواثيق الشرعة الدولية لحقوق الإنسان والمواثيق الدولية المعنية بمكافحة الإرهاب، كذلك المواثيق الإقليمية ومنها ميثاقا جامعة الدول العربية ومجلس التعاون لدول الخليج العربية الذي يضم في عضويته أربع دول خليجية منها ثلاث دول تقوم بالحصار؛ هي السعودية والإمارات والبحرين، والرابعة هي دولة قطر التي يقع عليها الحصار. على هذا الأساس توافرت شروط المسؤولية الدولية تجاه دول الحصار نتيجة ما أحدثه سلوكها غير المشروع من وقوع أضرار كبيرة على دولة قطر، وهو الأمر الذي يجيز للأخيرة تحريك المسؤولية الدولية تجاه دول الحصار، والحصول على التعويض المناسب لما وقع على الدولة ومؤسساتها ومواطنيها والمقيمين عليها من أضرار جسام.No doubt that the surprising and sudden decision taken by the Kingdom of Saudi Arabia (KSA), the United Arab Emirates (UAE), the Kingdom of Bahrain, and Egypt to boycott and impose a land, sea, air and diplomatic blockade on Qatar raises many issues relating to international relations, neighborhood relationships, and customs and traditions. The blockade imposed on Qatar resulted in many violations of the country’s economic, social, security and political rights, which are guaranteed by the international and regional treaties. This study demonstrates that the case of Qatar is a real blockade and not a boycott according to the definition of the term “blockade” from the linguistic and international jurisprudence perspectives. It shows that the blockading countries are lacking international references, mainly the Article 7 of the Charter of the United Nations that provides the Security Council solely the authority of taking such a decision according to the Article 41, ordering to take the necessary measures against the aggressing state(s) or those threatening the international peace and security. The Council may order the suspension of economic, rail transportation, maritime, air, postal, communication and telecommunication relations, partially or totally, or the suspension of diplomatic relations with such countries. Therefore, the blockade imposed on Qatar by the four countries is a clear violation of the international law and treaties, especially those relating to human rights and combatting terrorism. It also violates the regional treaties such as the Charter of the League of Arab States and the GCC, which includes three states imposing the blockade, namely KSA, UAE and Bahrain, and the fourth state, Qatar, which is the victim of the blockade. In this regard, the international responsibility of the blockading states is obvious because of the damaging effects of their act on the State of Qatar, which provides Qatar the right to set up a case of international responsibility against these countries and claim compensation due to the huge damage caused by the blockade on its institutions, citizens, and residents

Characterization and analysis of naturally fractured gas reservoirs based on stimulated reservoir volume and petro-physical parameters

© 2021, The Author(s). Fracture is one of the most important geological phenomena that affect the production of hydrocarbon compounds in broken carbonate reservoirs. However, fracture controlling factors must be combined with well data to achieve accurate fracture modeling. Therefore, structural data, drilling data, well flow diagrams, cores data, wells production data, and dynamic reservoir data have been considered here. Finally, by combining the above-mentioned information and through statistical and mathematical methods, the mechanism of fracture creation, general trends, and dominant fracture patterns are determined. These patterns are directly related to the tectonic regime and the stresses governing the region. For the first time, in this paper, we divided Zubair carbonate gas reservoir into 10 zones based on porosity and water saturation, and shale volume variation. We conclude that just four-zone of these are economic producible. Besides, the dominant lithology of this formation is more than limestone and a small number of thin shale layers. We defined types of cross-sectional petro-physical graphs and confirmed them by the geological graphic diagram prepared at the head

Purification and characterization of the first recombinant bird pancreatic lipase expressed in Pichia pastoris: The turkey

<p>Abstract</p> <p>Background</p> <p>The turkey pancreatic lipase (TPL) was purified from delipidated pancreases. Some biochemical properties and kinetic studies were determined using emulsified system and monomolecular film techniques. Those studies have shown that despite the accumulation of free fatty acids at the olive oil/water interface, TPL continues to hydrolyse efficiently the olive oil and the TC₄in the absence of colipase and bile salts, contrary to most classical digestive lipases which denaturate rapidly under the same conditions. The aim of the present study was to express TPL in the methylotrophic yeast <it>Pichia pastoris </it>in order to get a large amount of this enzyme exhibiting interesting biochemical properties, to purify and characterize the recombinant enzyme.</p> <p>Results</p> <p>The recombinant TPL was secreted into the culture medium and the expression level reached about 15 mg/l after 4 days of culture. Using Q-PCR, the number of expression cassette integrated on <it>Pichia </it>genomic DNA was estimated to 5. The purified rTPL, with molecular mass of 50 kDa, has a specific activity of 5300 U/mg on emulsified olive oil and 9500 U/mg on tributyrin. The optimal temperature and pH of rTPL were 37°C and pH 8.5. The stability, reaction kinetics and effects of calcium ions and bile salts were also determined.</p> <p>Conclusions</p> <p>Our results show that the expressed TPL have the same properties as the native TPL previously purified. This result allows us the use of the recombinant enzyme to investigate the TPL structure-function relationships.</p

Haute prévalence du Burnout dans les unités Tunisiennes prenant en charge des patients en fin de vie

Introduction: Chez le personnel soignant, le burnout touche un infirmier sur trois. Ce taux est plus élevé dans les unités prenant en charge des patients en fin de vie. L?objectif de notre travail était d?évaluer la fréquence du burnout chez les infirmiers qui travaillent en soins de fin de vie.Méthodes: Il s'agit d'une étude descriptive transversale réalisée entre le 1er Avril et le 31 Mai 2010. 60 infirmiers de six services de Sousse et de Monastir (Tunisie) ont été recrutés. L'évaluation du burnout a  été réalisée par deux échelles : MBI (Maslach Burnout Inventory) et BMS (Burnout Measure Short  version). Résultats: La prévalence du burnout était de 70% ; il était élevé chez 81.7%. 80% avaient un niveau  élevé d?épuisement émotionnel, 70% avaient un niveau élevé de dépersonnalisation et 17 % avaient un niveau bas de sentiment d'accomplissement personnel. Le burnout était plus élevé chez les hommes (70,8% vs 69,4% ; p=0,013) ; ceux qui voulaient améliorer les conditions du travail (70.2% vs. 66.7% ; p= 0.017) ; du salaire (70.2% vs. 66.7% ; p= 0.017) et chez les infirmiers suivi en psychiatrie (71.4%  vs. 69.8% ; p= 0.008).Conclusion: Dans notre étude le niveau de burnout était élevé chez les infirmiers prenant en charge des patients en fin de vie. Il était associé au sexe masculin et à l'insatisfaction des conditions de travail et du salaire. D'autres études longitudinales sont nécessaires pour suivre l'évolution de ce syndrome et mettre des stratégies de prévention adéquates.Key words: Burnout, infirmiers, soins de fin de vie, Tunisie

Multi-Model Wireless Federated Learning with Downlink Beamforming

This paper studies the design of wireless federated learning (FL) for simultaneously training multiple machine learning models. We consider round robin device-model assignment and downlink beamforming for concurrent multiple model updates. After formulating the joint downlink-uplink transmission process, we derive the per-model global update expression over communication rounds, capturing the effect of beamforming and noisy reception. To maximize the multi-model training convergence rate, we derive an upper bound on the optimality gap of the global model update and use it to formulate a multi-group multicast beamforming problem. We show that this problem can be converted to minimizing the sum of inverse received signal-to-interference-plus-noise ratios, which can be solved efficiently by projected gradient descent. Simulation shows that our proposed multi-model FL solution outperforms other alternatives, including conventional single-model sequential training and multi-model zero-forcing beamforming.Comment: 6 pages, 4 figures. Accepted by IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), 202

La performance environnementale augmente-t-elle la performance financière des entreprises économiques ?

Cette étude analyse la relation entre la performance environnementale et financière à travers des indicateurs utilisés dans les études empiriques précédentes de plusieurs pays dans le monde. Afin d’évaluer la relation entre ces deux indicateurs des performances au niveau de la diffusion de l’information et mettre en valeur la comptabilité sociétale surtout pour les marchés financiers.     Les résultats obtenus démontrent l’importance de processus concernant la divulgation des informations aussi son rôle pour améliorer la performance financière et économique des entreprises ; tout ça dans le cadre du marché financier efficient et des investisseurs conscients de la relation fusionnelle entre l’économie et l’environnement

Impact Of Composition And Salinity On Swelling And Gel Strength Of Poly (acrylamide-co-acrylic Acid) Preformed Particle Gel

The effects of various material compositions and reservoir environments on the ultimate strength and swelling kinetics of a commercial preformed particle gel (PPG) have been investigated. This study used different ratios of acrylamide and acrylic acid copolymers with a specific crosslinker concentration. Results have indicated that increasing the acrylic acid proportion enhances the PPGs\u27 ability to swell but weakens their network structure. In contrast, increasing the crosslinker content decreases the swelling ratio and increases the gel strength. The highest equilibrium swelling capacity among the six preformed particle gel samples was obtained for PPG2, which has the highest acrylic acid amount and the lowest crosslinker content, with a swelling ratio of 2400 g/g in deionized water and 59.8 g/g in brine 1 (67535.8 mg/l). On the contrary, PPG5, with the lowest acrylic acid and highest crosslinker content, has a swelling capacity of 239 g/g and more than 17 g/g in distilled and brine 1, respectively. Yet, PPG5 has the highest swollen gel strength of 615.5 Pa in deionized water and 3344 Pa in brine 1. The PPGs\u27 swelling ratios showed stepwise improvements along with increasing temperature, notably after 50 °C, yet the storage modulus (G′) was negatively affected. The PPGs revealed the highest swelling behavior in pH 6–8, decreasing dramatically in more acidic and basic conditions. The swelling ratios of the PPGs in brine 1 at 50 °C were between 12 and 32 g/g, having strengths in the range of 566–5508 Pa, depending on the crosslinker ratio. The PPGs also demonstrated the ability to compete with other commercial PPGs as they have shown physical and thermal stability when aging at 50 °C, specifically those with high crosslinker content (PPG5)

Development Of Eco-friendly Chitosan-g-polyacrylamide Preformed Particle Gel For Conformance Control In High-temperature And High-salinity Reservoirs

Oil and gas extraction has become challenging nowadays due to the accompanying amount of excess produced water that results in poor recoverability of hydrocarbon, besides other environmental and economic isues. A recent and efficient technology for conformance control is the injection of preformed particle gels (PPGs), which results in a more practical production process. Nevertheless, existing treatments fail in high-temperature reservoirs, are extremely sensitive to salinity, and are hazardous. The characteristics of the designed PPG, such as mechanical strength and thermal durability, is mainly depend on their crosslinking method. Polysaccharides-based gels prepared by physical crosslinking are weaker than the ones crosslinked by strong covalent bonding. This paper uses one of the polysaccharides and proposes an environmentally friendly PPG for water shutoff applications in reservoirs of high temperature (≤130 °C) and high salinity (200,000 ppm), named chitosan grafted polyacrylamide crosslinked with N, N′-methylene bisacrylamide, synthesized chemically by microwave assisted method. The PPG\u27s chemical compositions, grafting and crosslinking mechanism have been investigated by FTIR spectroscopy and SEM techniques. Swelling kinetics, swelling capacity, and mechanical strength measurements were conducted in different conditions to evaluate the influence of the reservoir conditions, such as salinity, temperature, and pH, on the PPG stability. TGA experiments were also performed to examine the thermal stability. Results have shown that the grafting method has produced a PPG with improved mechanical strength, thermal durability, and salt insensitivity. These results are consistent with the testing observations, where the swelling capacities and the storage modulusof Cs/PAMBA samples, with different MBA content, in deionized water were 2.72–11.64 g/g and 4272.1–22,687 Pa, respectively, while they are 2.52–13.82 g/g and 3699.6–22,910, respectively, in saline solution of TDS 67.2976 g/L. The PPGs are thermally stable and resist temperatures up to 130 °C. Besides being eco-friendly, the Cs/PAMBA showed good long-term thermal stability in high-temperature and high-salinity environments