Improved epoxy resin for constructing cryogenic filament-wound pressure vessels

Mechanical properties of new resin at cryogenic temperatures are substantially improved over similar composite structures utilizing conventional resins, while properties at ambient temperature are identical to conventional resin composites

Well-posedness and scalarization in vector optimization

In this paper we study several existing notions of well-posedness for vector optimization problems. We distinguish them into two classes and we establish the hierarchical structure of their relationships. Moreover, we relate vector well-posedness and well-posedness of an appropriate scalarization. This approach allows us to show that, under some compactness assumption, quasiconvex problems are well-posed.well-posedness, vector optimization problems, nonlinear scalarization, generalized convexity.

A Morse-type index for critical points of vector functions

In this work we study the critical points of vector functions form Rn to Rm with n m, following the definition introduced by S. Smale in the context of vector optimization. The local monotonicity properties of a vector function around a critical point which are invariant with respect to local coordinate changes are considered. We propose a classification of critical points through the introduction of an index for a critical point consisting of a triple of nonnegative integers. The proposed index is based on the ”sign” of an appropriate vector-valued second-order differential, that is proved to be invariant with respect to local coordinate changes. In order to avoid anomalous behaviours of the Jacobian matrix, the analysis is partially restricted to the proper critical points, a subset of critical points which enjoy stability properties with respect to perturbations of the order structure. Under nondegeneracy conditions, the index is proved to be locally constant. Moreover, the stability properties of the index with respect to perturbations both of the ordering cone and of the function are considered. Finally, the consistency of the proposed classification with the one given by Whitney for stable maps from the plane into the plane is proved. Keywords: Copula; Fréchet class; positive dependence stochastic ordering; right-tail decreasing (RTI); left-tail decreasing (LTD)

Box-constrained vector optimization: a steepest descent method without “a priori” scalarization

In this paper a notion of descent direction for a vector function defined on a box is introduced. This concept is based on an appropriate convex combination of the “projected” gradients of the components of the objective functions. The proposed approach does not involve an “apriori” scalarization since the coefficients of the convex combination of the projected gradients are the solutions of a suitable minimization problem depending on the feasible point considered. Subsequently, the descent directions are considered in the formulation of a first order optimality condition for Pareto optimality in a box-constrained multiobjective optimization problem. Moreover, a computational method is proposed to solve box-constrained multiobjective optimization problems. This method determines the critical points of the box constrained multiobjective optimization problem following the trajectories defined through the descent directions mentioned above. The convergence of the method to the critical points is proved. The numerical experience shows that the computational method efficiently determines the whole local Pareto front.Multi-objective optimization problems, path following methods, dynamical systems, minimal selection.

THE ROLES OF THE ACTIN NETWORK AND CO-OPTED HOST FACTORS IN TBSV REPLICATION

Positive-stranded (+) RNA viruses are the largest family of viruses that infect plants, causing important economic losses in different crops. Tomato bushy stunt virus (TBSV), a small positive-stranded RNA virus, has emerged as a model virus to study virus-host interactions. TBSV encodes for only five proteins, therefore, to infect the host cell TBSV co-opts selected host components and subverts specific molecular pathways. Firstly, I performed a proteomic screening using Arabidopsis proteins. I found that TBSV viral replication proteins interact with 88 host proteins, including the ubiquitin-conjugating enzyme 2 (Ubc2), fructose 1,6 biphosphate aldolase (Fba1), and several members of the Hps70 family. Ubc2 and its yeast ortholog Rad6 act as pro-viral factors promoting TBSV replication in plants and yeasts. Ubc2 and Rad6 ubiquitinate TBSV replication proteins to subvert ESCRT (endosomal sorting complexes required for transport) proteins for the viral replication complex (VRC) assembly. Similar to the yeast cytosolic Hsp70 (SSA1 and SSA2) I found that tombusviruses co-opt the constitutively expressed plant Hsp70-2 and the plant-specific stress-inducible Erd2 (early responsive to dehydration 2) to assemble the VRC and activate the TBSV RdRp, named p92pol. More, tombusviruses increase the accumulation levels of Hsp70 and Erd2 proteins in the cell during infection. These discoveries demonstrate that TBSV is able to co-opt more than one member of the Hsp70 family to promote viral replication. In addition, I found that TBSV viral replication proteins interact with Fructose 1,6 biphosphate aldolase (FBA1), a key enzyme in plants involved in glycolysis and glucogenesis. I discovered that FBA1 is a pro-viral factor necessary to locally produce ATP within the viral replication compartments and support tombusvirus replication. I used Legionella pneumophila effectors to disrupt actin dynamics and I found that the expression of the RavK effector, which cleaves the actin filaments, reduces tombusvirus replication in yeast and plants whereas the VipA effector, which polymerizes and stabilizes the actin filaments, enhances tombusvirus replication. Using RavK and VipA effectors as tools to study virus-hosts interactions, I found that actin dynamics is important for the efficient recruitment of glycolytic enzymes into the VRC to productively generate ATP at the replication sites. More, tombusviruses use Rpn11 deubiquitinase pro-viral host factor to recruit the glycolytic and fermentation enzymes to the site of replication via the actin network, thus the virus co-opts entire pathways facilitating viral replication and infection. Finally, I discovered that actin dynamics also affect the recruitment of cell-intrinsic restriction factors (CIRFs), like cyclophilins, co-chaperons, and helicases, to the replication sites. The stabilized actin network enhances the recruitment of pro-viral factors and reduces the recruitment of CIRFs into the VRC. Manipulation of the host actin network by tombusviruses during the early stage of infection is key for the tug-of-war between the virus and the host

A critical approach to soft power: Grasping contemporary Turkey’s influence in the world

I. Thinking Turkish influence in the midst of a dramatic political shift On 5 April 2015, Joseph Nye, the scholar who first coined the term “soft power”, was quoted in an article published in Today’s Zaman asserting that Turkish soft power had declined over the past few years. According to Nye, as a result Turkey would subsequently have “less soft power, less democracy”. During the 2000s, the concept of soft power became a popular term applied to the perceived rise in Turkey’s global and regi..