The lamellar structure of oriented high-density polyethylene

The lamellar structure of a high-density polyethylene oriented to give a single-crystal type of texture has been studied by electron microscopy and X-ray diffraction. Structures shown by the Kanig technique [6, 7] and a replication technique of electron microscopy are consistent with one another and with the small-angle X-ray diffraction patterns of this type of material, but the electron microscope observations show local regions of highly misoriented lamellae which are not detectable by X-ray diffraction. In regions where the lamellar orientation is that expected from the X-ray patterns the lamellae are wide and irregularly wavy.     

What lies behind requirements? A quality assessment of statement grounds in requirements elicitation

Software Quality Journal - In requirements engineering (RE), an early yet critical activity consists in eliciting the requirements from various stakeholders, who usually have different assumptions,...     

Life Courses and Ends of Career: Towards De-Standardization? An Analysis of the Belgian Case

For decades, scientists have alerted the authorities about the aging population and its socioeconomic consequences. Number of work carried out in sociology fit within the paradigm of the Life Course. These describe an evolution in two stages since the 19th century. In this article, we focus on the second phase characterized by a double process of de-standardization and de-institutionalization. From the example of ends of career, this article attempts to test the hypothesis of a de-standardization of age at the end of the labor market in Belgium. De-standardization involves increasing the diversity of situations. Statistically, this process should lead to an increase in variance around the average. This analysis is conducted using retrospective data for the cohorts born between 1905 and 1935, those ending their career between 1965 and 2001.     

Deformation mechanisms in oriented high density polyethylene

The deformation behaviour of single crystal texture HDPE has been examined in tension as a function of the orientation of the tensile axis with respect to the chain direction. Over most of the orientation range examined, it was found that slip processes parallel to the chain direction were the dominant modes of deformation. Fibrillar slip becomes relatively more important than chain slip as the strain increases and as ₀, the initial value of the angle between the tensile axis and the chain direction, decreases. Lamellar slip was only observed over a limited range of orientations due to the high initiation stress required for the process. At low ₀ values, lamellar separation accounted for a substantial part of the applied strain. Stress-induced martensitic transformation, which was observed in samples with ₀>26°, cannot account for an important fraction of the strain although the resolved shear stress required for the activation of the martensitic transformations is of the same order of magnitude as that required for chain slip.     

A framework for the operationalization of monitoring in business intelligence requirements engineering

Business intelligence (BI) is perceived as a critical activity for organizations and is increasingly discussed in requirements engineering (RE). RE can contribute to the successful implementation of BI systems by assisting the identification and analysis of such systems’ requirements and the production of the specification of the system to be. Within RE for BI systems, we focus in this paper on the following questions: (i) how the expectations of a BI system’s stakeholders can be translated into accurate BI requirements, and (ii) how do we operationalize specifically these requirements in a system specification? In response, we define elicitation axes for the documentation of BI-specific requirements, give a list of six BI entities that we argue should be accounted for to operationalize business monitoring, and provide notations for the modeling of these entities. We survey important contributions of BI to define elicitation axes, adapt existing BI notations issued from RE literature, and complement them with new BI-specific notations. Using the i* framework, we illustrate the application of our proposal using a real-world case study.     

Duality of the voltage-dependent calcium influx in adrenal glomerulosa cells

Both T- and L-type calcium channels are expressed in bovine adrenal glomerulosa cells and both channels are sensitive to moderate depolarizations of the cell membrane induced by angiotensin II (AngII) or physiological concentrations of extracellular K+. These channels present distinct pharmacology, L-type channels being more sensitive to dihydropyridines, whereas T channels are inhibited by lower concentrations of mibefradil, a new type of calcium antagonist currently used for treating hypertension. The activity of these channels is also differently modulated by AngII, which inhibits T channels through activation of protein kinase C and L channels through a Pertussis toxin-sensitive G protein. Finally, whereas the activity of L-type channels is directly reflected on the levels of the cytosolic calcium concentration ([Ca2+]c), T-type channels are more closely related to the control of steroidogenesis, possibly through a kind of "calcium pipeline" linking the plasma membrane to the mitochondria. In conclusion, two types of calcium channels, with distinct functions and differential modulation by AngII, are activated by agonists of aldosterone biosynthesis in adrenal glomerulosa cells. Most importantly, these channels have distinct sensitivities to currently used antihypertensive therapeutic drugs.