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The Hermans orientation factor is a scalar giving a simple assessment of molecular or crystal orientation in a polymer. It is usually determined from X-ray diffraction measurements. The evaluation of the Hermans orientation factor is proposed from the diffraction analysis of only a single diffracting plane. The estimation relies on (a) the assumption that the polymer crystals possess a cylindrical symmetry with respect to the chain direction and (b) that the processing conditions induce a transverse isotropy of the polymer chains. A practical consequence of the proposed analysis is that the Hermans orientation factor can be computed from a single ID diffractogram. This enables fast evaluations since even low signal-to-noise ratio signals can be processed with optimal noise reduction. An illustration of this method for uniaxially compacted polytetrafluoroethylene (PTFE) powder is presented. The crystalline orientation is followed during in situ crystallization experiments with a fine time resolution. KEYWORDS crystalline orientation, crystallization, PTFE, transverse isotropy, X-ray diffraction, 1 | INTRODUCTION The characterization of the molecular orientation in a polymer is of prime importance when evaluating its properties, and especially those related to mechanical behavior. [1] This orientation [...]

A nonlinear system, exhibiting a unique asymptotic behaviour, while being continuously subject to a stimulus from a certain class, is said to suffer from fading memory. This interesting phenomenon was first uncovered in a non-volatile tantalum oxide-based memristor from Hewlett Packard Labs back in 2016 out of a deep numerical investigation of a predictive mathematical description, known as the Strachan model, later corroborated by experimental validation. It was then found out that fading memory is ubiquitous in non-volatile resistance switching memories. A nonlinear system may however also exhibit a local form of fading memory, in case, under an excitation from a given family, it may approach one of a number of distinct attractors, depending upon the initial condition. A recent bifurcation study of the Strachan model revealed how, under specific train stimuli, composed of two square pulses of opposite polarity per cycle, the simplest form of local fading memory affects the transient dynamics of the aforementioned Resistive Random Access Memory cell, which, would asymptotically act as a bistable oscillator. In this manuscript we propose an analytical methodology, based on the application of analysis tools from Nonlinear System Theory to the Strachan model, to craft the properties of a generalised pulse train stimulus in such a way to induce the emergence of complex local fading memory effects in the nano-device, which would consequently display an interesting tuneable multistable oscillatory response, around desired resistance states. The last part of the manuscript discusses a case study, shedding light on a potential application of the local history erase effects, induced in the device via pulse train stimulation, for compensating the unwanted yet unavoidable drifts in its resistance state under power off conditions. [ABSTRACT FROM AUTHOR]

This article empirically investigates the role of import intermediaries in Canada and discusses how public policies can affect them. Among the main results is that intermediaries are shown to play a very different role with respect to manufacturers and retailers regarding differentiated and complex products, but their role is qualitatively the same across North American Free Trade Agreement (NAFTA) and non-NAFTA countries, and the share of intermediaries' imports is always boosted by a greater mass of small domestic manufacturers and retailers. These results suggest that import wholesalers play an important role in the Canadian economy, especially with respect to domestic manufacturers, and that policy-makers should be mindful of policy impacts on this sector. [ABSTRACT FROM AUTHOR]

Open spina bifida (OSB) is a congenital, non-lethal malformation with multifactorial etiology. Fetal therapy can be offered under certain conditions to parents after accurate prenatal diagnostic and interdisciplinary counseling. Since the advent of prenatal OSB surgery, various modifications of the original surgical techniques have evolved, including laparotomy-assisted fetoscopic repair. After a two-year preparation time, the team at the University of Giessen and Marburg (UKGM) became the first center to provide a three-port, three-layer fetoscopic repair of OSB via a laparotomy-assisted approach in the German-speaking area. We point out that under the guidance of experienced centers and by intensive multidisciplinary preparation and training, a previously described and applied technique could be transferred to a different setting. [ABSTRACT FROM AUTHOR]

Olive trees (Olea europaea L.) are deeply interwoven with the past, present and future of Mediterranean civilizations, both as essential economical as well as cultural valuables. Olive horticulture constitutes one of the primary agroecosystems in the Mediterranean regions of today. Being inhabitant of ecological niches, Olea europaea is prone to a peculiar vulnerability towards climatic and socioeconomical transformations that are briskly reshaping regional and global agroecosystems. Because of climatic changes and the biosafety risks of global agricultural trades, olive plants are highly susceptible to newly emerging diseases and pests, and the traditional olive horticultural crop protection practices are under scrutiny towards reducing their ecological impact. Hence there is an eminent demand for a more nature-positive olive tree crop management. Recent innovations in precision agriculture are raising the prospect for innovative crop protection methods that may provide olive farmers the required agility to respond to present and future agricultural challenges. For instance, endo-therapy, which is the systemic delivery of active ingredients via trunk injection, is a technology that holds promise of a true stepchange in sustainable olive crop management. Endo-therapy allows reaching vascular diseases inaccessible to foliar treatments and delivers active ingredients in a precise manner with no risks of off-target drifts. Similarly, progresses in biological precision delivery using controlled release of active ingredients based on innovative formulation technologies are showing an exciting potential for more targeted and sustainable crop protection solutions. This review summarizes the latest innovations on both physical and biological precision deliveries in the realm of olive arboriculture in the Mediterranean regions and gives an outlook how these technologies may help orchestrating innovative olive culture practices soon. [ABSTRACT FROM AUTHOR]

The influence of the cooling rate after melting on the crystalline weight fraction of pure poly (tetrafluoroethylene) (PTFE) was derived from differential scanning calorimetry tests. Specimens made of pure or filled PTFE were manufactured by isostatic or constrained uniaxial cold pressing, up to different values of the porosity. Dilatometry tests were carried out on these specimens while imposing various heating - cooling treatments. The deformations recorded during these tests strongly depend on the mode and level of compaction. The original procedures presented, herein, made it possible to identify that these macroscopic deformations, which are strongly anisotropic for uniaxially pressed specimens, result from the combination of different independent mechanisms. The mechanisms that were distinguished are reversible thermal expansion, void closure, crystalline to amorphous and vice versa transformations, and recovery, which were not observed for isostatically pressed specimens. It was also shown that, after being subjected to a standard sintering treatment, anisotropi - cally pressed specimens still exhibit anisotropic crystallization Strains. POLYM. ENG. SCI., 51: 2220 - 2235, 2011. © 2011 Society of Plastics Engineers, INTRODUCTION Because of its high molecular weight and very high melt viscosity, poly (tetrafluoroethylene) (PTFE) is a material, which cannot be produced by using conventional polymer melt processes. Parts made [...]

This paper shows that a manufacturer may benefit from parallel trade. In addition to an intuitive condition about the effect of demand shocks, this occurs when competitive retailers must order inventories before they know the realization of demand and for products whose sale value drops at the end of the demand period. For these types of products, letting retailers trade unsold inventories generally results in larger orders placed with the manufacturer and higher manufacturer profit. The model provides a simple explanation as to why the volume of parallel trade is now very large and accepted by manufacturers for some products such as automobiles, clothes, toys, consumer electronics, musical recordings, cosmetics and perfumes. Keywords: Parallel trade; Distribution JEL classification: F12

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jinteco.2005.06.011 Byline: Nicolas Schmitt (a)(c), Antoine Soubeyran (b) Keywords: Migration; Skilled workers; Entrepreneurs; Brain drain Abstract: This paper analyzes the allocation of two types of individuals differentiated by talent between two countries where they choose to be workers or entrepreneurs. An equilibrium with international migration exists when countries' talent endowments are sufficiently different. It is consistent with one-way or two-way migration whether individuals are entrepreneurs or workers. Although allowing migration increases domestic welfare in one country and decreases it in the other, it is always supported by majority voting in both countries. Author Affiliation: (a) Simon Fraser University, Canada (b) Universite de la Mediterranee, France and GREQAM, France (c) Universite de Geneve, Switzerland Article History: Received 24 October 2003; Revised 15 May 2005; Accepted 28 June 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jinteco.2005.06.005 Byline: Horst Raff (a), Nicolas Schmitt (b)(c) Keywords: International trade; Exclusive dealing; Common agency; Vertical restraints; Competition policy Abstract: This paper investigates the contractual choice between exclusive dealing and common agency in a simple international oligopoly model where products are sold through intermediaries. We find that when trade barriers are high, domestic firms tend to adopt exclusive dealing contracts whereas trade liberalization may lead firms to choose common agency. Social welfare can be raised be prohibiting exclusive dealing (common agency) when trade barriers are high (low) and products are close substitutes. Author Affiliation: (a) Institut fur Volkswirtschaftslehre, Christian-Albrechts-Universitat zu Kiel, D-24098 Kiel, Germany (b) Department of Economics, 8888 University Drive, Simon Fraser University, Burnaby, Canada V5A 1S6 (c) Departement d'economie politique, Universite de Geneve, CH-1211 Geneve 4, Switzerland Article History: Received 9 February 2004; Revised 22 May 2005; Accepted 22 June 2005

This paper investigates the contractual choice between exclusive dealing and common agency in a simple international oligopoly model where products are sold through intermediaries, We find that when trade barriers are high, domestic firms tend to adopt exclusive dealing contracts whereas trade liberalization may lead firms to choose common agency. Social welfare can be raised be prohibiting exclusive dealing (common agency) when trade barriers are high (low) and products are close substitutes. Keywords: International trade; Exclusive dealing; Common agency; Vertical restraints; Competition policy

This paper examines interbrand competition between a domestic and a foreign manufacturer who market their products through intermediaries. The contracts manufacturers offer these intermediaries are endogenous. In equilibrium contracts may specify exclusive territories (ET), depending on the degree of substitutability between products and the level and degree of transparency of trade barriers. Trade liberalization, through lower or more transparent barriers, may lead manufacturers to use ET, thereby substituting private anticompetitive arrangements for government-imposed barriers. This substitution may decrease competition and welfare, and thus create a role for competition policy in a freer trade environment. JEL classification: F13; L42 Keywords: International trade; Contracts; Vertical restraints

This paper argues that new immigrants cluster in culturally homogeneous groups in the host country because of imperfect information. However, a pulling effect exists provided that the cultural communities are not too large. With a panel of migration flows to the major O.E.C.D. countries from the mid 1980s to the mid 1990s, it is shown that the existence of similar cultural communities attracts new immigrants. However, the effect is not homogeneous for all types of source and destination countries. Furthermore, the pulling effect is shown to fall to zero for cultural communities above a certain threshold size.

This article shows that governments have no incentive to introduce nontariff barriers (NTBs) when they are free to set tariffs but they do when tariffs are determined cooperatively. Quotas are preferred to antidumping restrictions so that the model is consistent with a progression from using tariffs only to quotas and then to antidumping constraints (when quotas are eliminated). There is a corresponding narrowing of the range of industries affected by trade restrictions. Simulating the model, the degree of tariff liberalization and of replacement of tariffs by NTBs are shown to depend on industry characteristics in line with stylized facts. (JEL F12, F13, L13), I. INTRODUCTION It is common to recognize that tariffs have gradually been replaced by nontariff barriers (NTBs). Some authors go even further and argue there is a 'Law of Constant [...]