A hypoelastic model for soils—II: A class of hypoelastic materials. Properties

A study of the mechanical behaviour of a special class of hypoelastic materials taking into account different stress histories.     

Methods of non-linear stochastic dynamics for the assessment of structural fragility

Some of the external events which can significantly contribute to the overall risk of a nuclear power plant, give rise to a dynamic excitation of the structural components which form the plant. The computation of the risk associated with these external events requires an investigation of the behaviour of the structural components beyond the elastic limit. The stochastic nature of the excitation, then, leads one to deal with a non-linear stochastic dynamic problem.

No general method of solution exists for such a problem when large structural systems are considered, although classical methods of propagating uncertainty have been successfully employed. This paper investigates the possibility of formulating an approach founded on a suitable equivalent linearization technique. In particular the authors make operative a new method of fragility analysis to be applied directly to the linearized system.

The numerical example considers a framed structural component: its aim is to show the degree of accuracy that can be reached by the approach formulated in the paper.     

The validation of expressed interests as compared with inventoried interests: a fourteen-year follow-up.

Of 63 sophomores in 1939-40, who took the Strong VIB and a social history interview, occupational choice follow-up data were available in 1953 for 60 Ss. "Apparently the Strong… is most applicable to men reared in the middle class success culture. The Strong seems less applicable for those upper-middle and upper class groups who possess an alternative culture. Among this group, expressed interests are more accurate predictors than the test scores. The inventory predicts Ambitious Careers (feeling… that higher occupational goals can be attained) while the expressed interests predict Responsive Careers (feeling of acceptance with job progression which parents or relatives expect worker to follow)." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural investigation of the HIV-1 envelope glycoprotein gp160 cleavage site, 2: relevance of an N-terminal helix

Proteolytic activation of the HIV-1 envelope glycoprotein gp160 is selectively performed by the proprotein convertase furin at the C-terminus of the sequence R508-E-K-R511 (site 1), in spite of the presence of another consensus sequence, Lys500-Ala-Lys-Arg503 (site 2). On the basis of the solution structural analysis of the synthetic peptide p498, spanning the gp160 sequence Pro498-Gly516, we previously suggested a possible role of an N-terminal helix in regulating the exposure and accessibility of the gp160 physiological cleavage site, enclosed in a loop. Here we report on the activity and conformation of the 23-residue peptide h-REKR, designed to exhibit a large N-terminal helix, followed by the gp160 native sequence, Arg508-Gly516. h-REKR is digested by furin with high efficiency, comparable to the full native p498. Circular dichroism analyses, in mixtures from pure water to 98 % trifluoroethanol, outline a significant content of helical structure in the peptide conformation. The molecular model obtained from NMR data collected in trifluoroethanol/water, by means of DYANA and AMBER simulations, indeed has helical structure on a large N-terminal segment. Such a long helix does not seem to affect the loop conformation of the C-terminal site 1-containing sequence, which exhibits the same proton chemical shifts already observed for the full native p498.     

Cache Decision Making: The Effects of Competition on Cache Decisions in Merriam's Kangaroo Rat (Dipodomys merriami).

Caching food is an economic, decision-making process that requires animals to take many factors into account, including the risk of pilferage. However, little is known about how food-storing animals determine the risk of pilferage. In this study, the authors examined the effect of a dominant competitor species on the caching and behavior of Merriam's kangaroo rat (Dipodomys merriami). The authors found that, as with conspecific competitors, kangaroo rats did not alter caching in response to the mere presence of a heterospecific competitor, but moved caches to an unpreferred area when the competitor's presence was paired with pilferage. These data suggest that Merriam's kangaroo rat assesses pilfer risk from actual pilferage by a competitor and adaptively alters cache strategy to minimize future risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and fabrication of a hybrid silicon three-axial force sensor for biomechanical applications

This paper presents the design and development of a silicon-based three-axial force sensor to be used in a flexible smart interface for biomechanical measurements. Normal and shear forces are detected by combining responses from four piezoresistors obtained by ion implantation in a high aspect-ratio cross-shape flexible element equipped with a 525 μm high silicon mesa. The mesa is obtained by a subtractive dry etching process of the whole handle layer of an SOI wafer. Piezoresistor size ranges between 6 and 10 μm in width, and between 30 and 50 μm in length. The sensor configuration follows a hybrid integration approach for interconnection and for future electronic circuitry system integration. The sensor ability to measure both normal and shear forces with high linearity (99%) and low hysteresis is demonstrated by means of tests performed by applying forces from 0 to 2 N. In this paper the packaging design is also presented and materials for flexible sensor array preliminary assembly are described.     

Assessment of multitemporal compositing techniques of MODIS and AVHRR images for burned land mapping

The performance of several criteria to generate multitemporal composites of daily Moderate Resolution Imaging Spectrometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) images for burned land mapping was tested using data acquired over the Iberian Peninsula in 2001, 2003 and 2004. The experiment was based on four tests that assessed the discriminability between burned and unburned areas, the presence of artifacts (clouds and clouds shadows), the verticality of the sensor viewing angle, and the spatial coherency of the composite images. Seven different compositing techniques were tested, based on maximizing normalized difference vegetation index (NDVI) and brightness/surface temperature, and minimizing reflectance and sensor zenith angles. The composite criterions that provide the most accurate images for burned land mapping were based on maximizing brightness/surface temperatures, either as the only criterion or in conjunction with minimizing sensor zenith angle or near infrared (NIR) reflectance. These composites present high discrimination capacity between burned and unburned areas, remove most clouds and cloud shadows, offer high spatial coherency and present middle-to-low sensor zenith angles. Traditional compositing criterion based on maximizing NDVI values provided poor results in most tests. Finally, standard NASA MODIS composite provides close to nadir observation angles, and good spatial coherency, but it offered lower discrimination between burned and unburned areas that those composites based on thermal data.     

Corporate diversification, coherence and economic performance

Within the diversification literature the concept of corporatecoherence has been referred to as the ability of the firm togenerate and explore synergies of various types. However, theempirical studies have insofar provided only approaches takingexplicitly into account the product/market side of the phenomenon.The present paper operationalizes the concept of corporate coherenceas a dynamic interconnectedness between the company’stechnological competencies and its downstream activities. Italso provides some further empirical evidence on the widelydiscussed relationship between corporate diversification andperformance. Specifically, it offers some (albeit rather weak)evidence that economic performance is positively influencednot by the degree of diversification per se, but by the abilityof the company to increase its corporate coherence.     

Investigation of the solid flow between two fluidized beds connected by an orifice

Two adjacent fluidized beds separated by a wall can exchange solids through an orifice due to the local pressure oscillations on both sides of the orifice produced by passing bubbles. This flow of solids between the two fluidized bed reactors is sufficient for some practical applications where a highly integrated, simple and cost-effective arrangement might be required. Solid transfer rates through orifices of different geometries and dimensions have been measured in this work using a novel image analysis technique. The measured solid fluxes can reach up to in some experimental conditions. An empirical correlation has been proposed to fit the available experimental data as a function of key operating conditions.