On the impact of physical layer awareness on scheduling and resource allocation in broadband multicellular IEEE 802.16 systems [Radio Resource Management and Protocol Engineering for IEEE 802.16]

Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions     

Vacuum-u.v. circular dichroism of optically active isotactic poly-α-olefins

Summary Circular dichroism of isotactic samples of poly-(S)-4-methyl-1-hexene and poly-(R)-3,7-dimethyl-1-octene, have been measured in the vacuum ultraviolet spectral region (200-140 nm). The c.d. band at about 160. nm accounts for the optical activity in the visible region and reflects the presence of one screw sense helical conformation of the sample examined.The authors thank Prof. W.C. Johnson, Jr., Department of Biochemistry and Biophysics, Oregon State University, for allowing them to use the vacuum u.v. spectrometer. This work has been partially supported by a N.A.T.O. grant, and by Ministero Pubblica Istruzione (MPI), Roma — Italy.     

Ionomer composites based on sepiolite/hydrogenated poly(styrene butadiene) block copolymer systems

Ionomeric composites based on sepiolite and hydrogenated poly(styrene butadiene) block copolymer were obtained and characterized from a microstructural and electrical point of view. Before blending, because of the high silanol group concentration in the sepiolite, the latter could be organophilized with suitable coupling agents. The resulting materials were easily processed into thin films or membranes 0.2–0.4 mm thick, their conductivity in some cases approaching 10^?1 S/cm. Their suitability for film formation and good electrical properties indicate potential applications as electrolytes in polymer fuel cells. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3512–3519, 2002     

Large deflections and stability FEM analysis of shear deformable compressed anisotropic flat panels

This paper deals with the non-linear analysis of multilayered axially compressed plates in the static elastic conservative cases. A finite element model based on a Reissner-Mindlin theory involving von Kármán nonlinearity is developed. Results related to the classical Kirchhoff plate approximations are obtained via application of a penalty technique to the shear correction factor. The numerical investigations have concerned the large deflections and postbuckling behaviour of symmetrically and non-symmetrically anisotropic flat panels. The main conclusions are: (1) the non-linear effects very much depend on lay-up and boundary conditions, moreover for the asymmetric laminated long plates the snapping-type instability occurs; (2) the shear deformation effects are very much subordinate to both multilayered lay-up and load levels, furthermore they are greater in the large deflections field; (3) it has been observed that in the neighbourhood of a singularity (of buckling point type) of the tangent stiffness matrix, the use of an arc-length type algorithm could lead to a new buckled path and that happens without employing an appropriate turning bifurcation algorithm with an accompanying eigenvalues calculation, but via a non-convergent iteration in the loadstep.     

Steps towards a consumer-driven ‘concept innovation machine’ for food and drink

Innovation is often left to insight and serendipity. A lot of what researchers call innovation is actually a process by which one can make the individual consumer or practitioner more ‘creative’. Although it is important to work with the creative individual in hopes of coming up with the better ‘idea’ and new product/service opportunity, an equally valid albeit novel and counterintuitive approach systematizes creativity in a ‘research-driven machine’. This paper presents an approach to the systematization, based upon the point of view that creativity and innovation comprise the recombination of components into new blends. Given this point of view, to then spur innovation requires a systematic database that the user can access, with tools to help manipulate that database. The paper shows how such a database can be constructed and then used to create a novel product. The approach provides a general framework for the sensory professional to become more involved in the early stages of product development, where the focus is on the conceptual aspects of food features rather than on their physical manifestations in actual products.     

Effects of temperature, ammonium and glucose concentrations on yeast growth in a model wine system

In enology, alcoholic fermentation is a complex process involving several mechanisms. Slow and incomplete alcoholic fermentation is a chronic problem for the wine industry and factors leading to sluggish and stuck fermentations have been extensively studied and reviewed. The most studied cause of sluggish and stuck fermentation is the nitrogen content limitation. Nevertheless, other factors, such as temperature of fermentation and sugar concentration can affect the growth of yeasts. In this study we modelled the yeast growth‐cycle in wine model system as a function of temperature, sugar and ammonium concentrations; the individual effects and the interaction of these factors were analysed by means of a quadratic response surface methodology. Cell concentrations and weight loss were monitored in the whole wine fermentation process. The results of central composite design show that lower is the availability of nitrogen, higher is the cell growth rate; moreover, initial nitrogen concentration also influences survival time of Saccharomyces cerevisiae.     

Kinetic study of the reaction between molybdenum trioxide and gaseous carbon tetrachloride

The kinetics of the chlorination reaction of molybdenum trioxide with gaseous carbon tetrachloride has been studied at temperatures between 713 and 753 K. The effects of temperature, reaction time, residence time and gaseous reactant concentration on conversion were studied throughout the reaction. In all cases, there was an increase in conversion when the above operating variables were increased. The kinetic model proposed is consistent with and correlates the experimental data. In the range studied for the different variables, the step that controls the rate of reaction is the surface chemical reaction. Values of the rate constant and the activation energy were estimated.     

Influence of Carrier Mobility and Interface Trap States on the Transfer and Output Characteristics of Organic Thin Film Transistors

We have used two dimensional drift diffusion simulations to calculate the electrical properties of bottom contact pentacene based organic thin film transistor, taking into account field-dependent mobility and interface or bulk trap states. In order to derive from basic principles the transport properties of the organic semiconductor we have developed a Monte Carlo simulator to calculate the field dependent mobility. We analyzed the presence of trap states at the interface between organic material and gate insulator and we show the influence of trap states combined with the effect of field-dependent mobility on the transfer characteristic. Numerical calculations are also reported for the output characteristics of the device showing a very good agreement with the available experimental results.     

When more is less: A counterintuitive effect of distractor frequency in the picture-word interference paradigm.

Pictures were shown with superimposed word distractors of high and low frequency. Low-frequency distractors produced greater interference on picture naming than did high-frequency distractors. This distractor frequency effect was not affected by manipulations that facilitated or hindered distractor recognition. Interference was reduced for distractors that were read aloud several times prior to being shown in the picture-naming task. Together these findings suggest that the distractor frequency effect has its locus at some stage of lexical access for production. Other findings further constrain hypotheses about which level of speech production is involved in the effect. The distractor frequency effect has implications for models of lexical processing in speaking as well as for accounts of picture-word interference and the frequency effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Value of early variables as predictors of short-term outcome in patients with acute focal cerebral ischemia

The pathogenesis of essential thrombocythemia as a clonal myeloproliferative disorder has been clearly established. However, there continues to be considerable controversy concerning the management of this disease, particularly because its natural history is consistent with a nearly normal life expectancy. Therapeutic decisions have been complicated by a reliance on largely anecdotal, retrospective experience in the medical literature and, until very recently, an absence of prospective, controlled clinical trials. A recent study of patients with essential thrombocythemia at high risk of thrombosis because of advanced age or previous history of thrombotic complications demonstrated that platelet cytoreduction with hydroxyurea is effective in reducing thrombotic complications. Other cytoreducing agents that have been used in this disease include alkylating agents, recombinant interferon alpha, and anagrelide. The use of antiplatelet therapy is also controversial, and is most highly effective in patients with digital or cerebrovascular ischemic problems.