PVP2007-26361 LINEAR AND NONLINEAR FINITE ELEMENT ANALYSIS OF AN EXHAUST MANIFOLD WITH INCLUDED BELLOWS

ABSTRACT: The aim of this paper is to examine the utility of nonlinear analysis for structural response to thermal and mechanical loads, for a structure containing alternating regions of high and low stiffness as a result of inclusion of bellow sections. Utility is measured by comparison of results of linear and nonlinear analyses. The specific example used is that of an exhaust manifold for a large diesel engine. The paper discusses modeling of geometric and material nonlinearity, and makes recommendations in regard to which nonlinear effects are thought to be significant, based on the linear/nonlinear comparisons. The paper also contains general comments on the finite element modeling of structures containing bellows

Differences in Brain Function and Changes with Intervention in Children with Poor Spelling and Reading Abilities

Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training

Introduction into the Study of Markets

The three introductory chapters on how to study production, market, and money and credit provide frames for the reviewed sample studies in Chaps. 6, 7 and 8. They offer some guidance in finding your bearings in the jungle of concepts and debates which makes premodern economic history such an interesting, but challenging subject to study. Each chapter structures important and current debates in the field and explains the basic concepts used in these discussions. Most debates concern the premodern European economy in general. Whenever possible, we refer to corresponding studies for the Holy Roman Empire. We point to classic works as well as to newer studies but offer no exhaustive compilation of all the research done in the area

The role of NK cells in HIV-1 protection : autologous, allogeneic or both?

Natural killer (NK) cells specialize in killing virally infected- or tumor cells and are part of the innate immune system. The activational state of NK cells is determined by the balance of incoming activating and inhibitory signals mediated by receptor-ligand binding with the target cell. These receptor-ligand bonds mainly consist of the killer immunoglobulin-like receptors (KIR), which are expressed at the cell surface of NK cells, and their ligands: the highly variable human leukocyte antigen -class I molecules (HLA). Absence of an inhibitory receptor-ligand bond lowers the NK cell activation threshold, whereas an activating receptor-ligand bond stimulates the cell, potentially overcoming this threshold and triggering NK cell activation. NK cells influence the course of infection as well as the acquisition of HIV-1. Several lines of evidence relate the activating NK cell receptor KIR3DS1, in the presence or absence of its putative ligand HLA-Bw4, with slower disease progression as well as resistance to HIV-1 infection. Overall, resistance to HIV-1 infection predominantly correlates with activating KIR/HLA profiles, consisting of e.g. activating KIRs, group B haplotypes, or inhibitory KIRs in absence of their ligands. Such a conclusion is less evident for studies of HIV-1 disease progression, with studies reporting beneficial as well as detrimental effects of activating KIR/HLA genotypes. It is likely that KIR/HLA association studies are complicated by the complexity of the KIR and HLA loci and their mutual interactions, as well as by additional factors like route of HIV exposure, immune activation, presence of co-infections, and the effect of anti-HIV-1 antibodies. One newly discovered NK cell activation pathway associated with resistance to HIV-1 infection involves the presence of an iKIR/HLA mismatch between partners. The absence of such an iKIR/HLA bond renders donor-derived allogeneic HIV-1 infected cells vulnerable to NK cell responses during HIV-1 transmission. Therefore, theoretically, HIV-1 would be eliminated before it has the chance to infect the autologous cells in the recipient. While this “alloreactive” NK cell mechanism is especially relevant to HIV transmission in monogamous couples, it would be interesting to investigate how it could influence resistance to HIV in other settings. The objective of this review is to summarize the knowledge about these autologous and alloreactive NK cell responses with regard to HIV-1 outcome