A systematic review of contract farming and it's impacts on broiler producers in Lebanon

This Thesis has been realized within the agribusiness sector and experiments the Transaction Cost Theory a branch of the New Institutional Economy which explain market failure caused by many factors. Transaction costs are associated with carrying a transaction between buyers and sellers. This study has been conducted between 2014 and 2017; and has collected data from 11 broiler producers in Jezzine, Lebanon, about: Production costs, capital investment, revenues, land tenure, access to infrastructure, and information about the contract. The propensity score matching method is used to compare the effect of participating in contract farming and to solve the hypotheses, which say: There is a positive relationship between contract farming and the economic benefits of broiler producers and the development of the broiler sector in Jezzine District. Findings from farmer’s interviews indicated that sustainability, guaranteed price, risk reduction, credit facilities and technical aids are the main reasons for signing a contract. In contrast, Farmers have expressed problems concerning the contractors’ responsibilities such as delay in payment and delivery. Also, when prices are high, it was argued that farmers were selling the products in the open market

Statistical Power Supply Dynamic Noise Prediction in Hierarchical Power Grid and Package Networks

One of the most crucial high performance systems-on-chip design challenge is to front their power supply noise sufferance due to high frequencies, huge number of functional blocks and technology scaling down. Marking a difference from traditional post physical-design static voltage drop analysis, /a priori dynamic voltage drop/evaluation is the focus of this work. It takes into account transient currents and on-chip and package /RLC/ parasitics while exploring the power grid design solution space: Design countermeasures can be thus early defined and long post physical-design verification cycles can be shortened. As shown by an extensive set of results, a carefully extracted and modular grid library assures realistic evaluation of parasitics impact on noise and facilitates the power network construction; furthermore statistical analysis guarantees a correct current envelope evaluation and Spice simulations endorse reliable result

You Only Live Multiple Times: A Blackbox Solution for Reusing Crash-Stop Algorithms In Realistic Crash-Recovery Settings

Distributed agreement-based algorithms are often specified in a crash-stop asynchronous model augmented by Chandra and Toueg\u27s unreliable failure detectors. In such models, correct nodes stay up forever, incorrect nodes eventually crash and remain down forever, and failure detectors behave correctly forever eventually, However, in reality, nodes as well as communication links both crash and recover without deterministic guarantees to remain in some state forever. In this paper, we capture this realistic temporary and probabilitic behaviour in a simple new system model. Moreover, we identify a large algorithm class for which we devise a property-preserving transformation. Using this transformation, many algorithms written for the asynchronous crash-stop model run correctly and unchanged in real systems

Distortionary Taxation and Labor Supply: Evidence from Canada

This paper examines empirically the effects of distortionary taxation on labor supply using a general equilibrium framework. The long-term relations predicted by the model are derived and tested using Canadian data between 1966 and 1993. While the cointegrating predictions of the model without taxation are rejected, the ones of the model with labor taxation are not. Persistent labor tax rate increases appear to play an important role in the observed downward trend in hours worked.Cet article examine de façon empirique les effets des taxes distorsionnaires sur l'offre de travail dans le cadre d'un modèle d'équilibre général. Les relations de long terme impliquées par le modèle sont dérivées et testées en utilisant des données canadiennes entre 1966 et 1993. Alors que les relations de coïntégration prédites par le modèle sans taxe distorsionnaire sont rejetées par les données, celles avec taxe ne le sont pas. Les accroissements persistants du taux de taxation du revenu de travail semblent jouer un rôle important dans la tendance décroissante observée des heures travaillées

Reliable and Real-Time Distributed Abstractions

The celebrated distributed computing approach for building systems and services using multiple machines continues to expand to new domains. Computation devices nowadays have additional sensing and communication capabilities, while becoming, at the same time, cheaper, faster and more pervasive. Consequently, areas like industrial control, smart grids and sensor networks are increasingly using such devices to control and coordinate system operations. However, compared to classic distributed systems, such real-world physical systems have different needs, e.g., real-time and energy efficiency requirements. Moreover, constraints that govern communication are also different. Networks become susceptible to inevitable random losses, especially when utilizing wireless and power line communication. This thesis investigates how to build various fundamental distributed computing abstractions (services) given the limitations, the performance and the application requirements and constraints of real-world control, smart grid and sensor systems. In quest of completeness, we discuss four distributed abstractions starting from the level of network links all the way up to the application level. At the link level, we show how to build an energy-efficient reliable communication service. This is especially important for devices with battery-powered wireless adapters where recharging might be unfeasible. We establish transmission policies that can be used by processes to decide when to transmit over the network in order to avoid losses and minimize re-transmissions. These policies allow messages to be reliably transmitted with minimum transmission energy. One level higher than links is failure detection, a software abstraction that relies on communication for identifying process crashes. We prove impossibility results concerning implementing classic eventual failure detectors in networks with probabilistic losses. We define a new implementable type of failure detectors, which preserves modularity. This means that existing deterministic algorithms using eventual failure detectors can still be used to solve certain distributed problems in lossy networks: we simply replace the existing failure detector with the one we define. Using failure detectors, processes might get information about failures at different times. However, to ensure dependability, environments such as distributed control systems (DCSs), require a membership service where processes agree about failures in real time. We prove that the necessary properties of this membership cannot be implemented deterministically, given probabilistic losses. We propose an algorithm that satisfies these properties, with high probability. We show analytically, as well as experimentally (within an industrial DCS), that our technique significantly enhances the DCS dependability, compared to classic membership services, at low additional cost. Finally, we investigate a real-time shared memory abstraction, which vastly simplifies programming control applications. We study the feasibility of implementing such an abstraction within DCSs, showing the impossibility of this task using traditional algorithms that are built on top of existing software blocks like failure detectors. We propose an approach that circumvents this impossibility by attaching information to the failure detection messages, analyze the performance of our technique and showcase ways of adapting it to various application needs and workloads

Construction d'un adénovirus recombinant codant pour la molécule pro-apototique TRAIL : but : étude du rôle de TRAIL in vivo et de son potentiel thérapeutique

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Qualitative Analysis for Validating IEC 62443-4-2 Requirements in DevSecOps

Validation of conformance to cybersecurity standards for industrial automation and control systems is an expensive and time consuming process which can delay the time to market. It is therefore crucial to introduce conformance validation stages into the continuous integration/continuous delivery pipeline of products. However, designing such conformance validation in an automated fashion is a highly non-trivial task that requires expert knowledge and depends upon the available security tools, ease of integration into the DevOps pipeline, as well as support for IT and OT interfaces and protocols. This paper addresses the aforementioned problem focusing on the automated validation of ISA/IEC 62443-4-2 standard component requirements. We present an extensive qualitative analysis of the standard requirements and the current tooling landscape to perform validation. Our analysis demonstrates the coverage established by the currently available tools and sheds light on current gaps to achieve full automation and coverage. Furthermore, we showcase for every component requirement where in the CI/CD pipeline stage it is recommended to test it and the tools to do so

Targeting SARS-CoV-2 infection through CAR-T-like bispecific T cell engagers incorporating ACE2.

OBJECTIVES: Despite advances in antibody treatments and vaccines, COVID-19 caused by SARS-CoV-2 infection remains a major health problem resulting in excessive morbidity and mortality and the emergence of new variants has reduced the effectiveness of current vaccines. METHODS: Here, as a proof-of-concept, we engineered primary CD8 T cells to express SARS-CoV-2 Spike protein-specific CARs, using the extracellular region of ACE2 and demonstrated their highly specific and potent cytotoxicity towards Spike-expressing target cells. To improve on this concept as a potential therapeutic, we developed a bispecific T cell engager combining ACE2 with an anti-CD3 scFv (ACE2-Bite) to target infected cells and the virus. RESULTS: As in CAR-T cell approach, ACE2-Bite endowed cytotoxic cells to selectively kill Spike-expressing targets. Furthermore, ACE2-Bite neutralized the pseudoviruses of SARS-CoV, SARS-CoV-2 wild-type, and variants including Delta and Omicron, as a decoy protein. Remarkably, ACE2-Bite molecule showed a higher binding and neutralization affinity to Delta and Omicron variants compared to SARS-CoV-2 wild-type Spike proteins. CONCLUSION: In conclusion, these results suggest the potential of this approach as a variant-proof, therapeutic strategy for future SARS-CoV-2 variants, employing both humoral and cellular arms of the adaptive immune response