359 research outputs found
An optimal battery interchange policy for an electric car powered by a mobile solar power station
The World Solar Challenge is a 3000 kilometre race from Darwin to Adelaide, across the Australian continent, for solar powered racing cars. Annesley College accompanied the 2001 event in an electric car powered by batteries. While one battery was used to power the car another was charged from a solar panel carried by a mobile solar power station. When the first battery became empty the batteries were interchanged and the first battery put on charge. The process was repeated throughout the event. In this paper we find a policy for interchanging the batteries that maximises the distance travelled each day
Solar Orbiter Strategies for EMC Control and Verification
Solar Orbiter, due for launch in February 2020, is an ESA mission to investigate how the Sun creates and controls the heliosphere. Solar Orbiter will combine insitu particle and field measurements with remote sensing observations of the Sun taken as close as 0.28AU (astronomical units). In order to make in-situ measurements, particularly at particle kinetic scales, it is necessary to establish and maintain control of the electro-static (ESC) and electro-magnetic compatibility (EMC), between platform and instruments alike. We present the strategies employed in the ESC/EMC control of the Solar Orbiter mission, touching on the properties of key equipment such as the Solar Arrays, Reaction Wheels and Instrument Boom (I-Boom), and the proposed verification methodology for the system level EMC test campaign due to take place in 2019
Tourists’ expenditure behaviour: the influence of satisfaction and the dependence of spending categories.
A review of the literature shows that the relationship between satisfaction and tourism expenditure, as well as the dependence among different tourist expenditure categories, are under-researched topics. The aim of this study is twofold: first, to investigate the influence on tourism expenditure of tourists’ satisfaction with the destination, correcting for the effect of some socio-demographic and trip-related variables; second, to study the dependence among tourist expenditure on the different tourist categories that create the overall expenditure for the trip. This study focuses on an analysis of the expenditure behaviour of a sample of international visitors who travelled in an area around the Dolomites in Northern Italy, adopting the doublehurdle model with the Heien and Wessells estimator. In discussing the results, policy implications and managerial issues for tourism destinations are presented
A CD8+ T cell immune evasion protein specific to Epstein-Barr virus and its close relatives in Old World primates
γ1-Herpesviruses such as Epstein-Barr virus (EBV) have a unique ability to amplify virus loads in vivo through latent growth-transforming infection. Whether they, like α- and β-herpesviruses, have been driven to actively evade immune detection of replicative (lytic) infection remains a moot point. We were prompted to readdress this question by recent work (Pudney, V.A., A.M. Leese, A.B. Rickinson, and A.D. Hislop. 2005. J. Exp. Med. 201:349–360; Ressing, M.E., S.E. Keating, D. van Leeuwen, D. Koppers-Lalic, I.Y. Pappworth, E.J.H.J. Wiertz, and M. Rowe. 2005. J. Immunol. 174:6829–6838) showing that, as EBV-infected cells move through the lytic cycle, their susceptibility to EBV-specific CD8+ T cell recognition falls dramatically, concomitant with a reductions in transporter associated with antigen processing (TAP) function and surface human histocompatibility leukocyte antigen (HLA) class I expression. Screening of genes that are unique to EBV and closely related γ1-herpesviruses of Old World primates identified an early EBV lytic cycle gene, BNLF2a, which efficiently blocks antigen-specific CD8+ T cell recognition through HLA-A–, HLA-B–, and HLA-C–restricting alleles when expressed in target cells in vitro. The small (60–amino acid) BNLF2a protein mediated its effects through interacting with the TAP complex and inhibiting both its peptide- and ATP-binding functions. Furthermore, this targeting of the major histocompatibility complex class I pathway appears to be conserved among the BNLF2a homologues of Old World primate γ1-herpesviruses. Thus, even the acquisition of latent cycle genes endowing unique growth-transforming ability has not liberated these agents from evolutionary pressure to evade CD8+ T cell control over virus replicative foci
Coupled Motions Direct Electrons along Human Microsomal P450 Chains
Directional electron transfer through biological redox chains can be achieved by coupling reaction chemistry to conformational changes in individual redox enzymes
Secondary Structure and Glycosylation of Mucus Glycoproteins by Raman Spectroscopies
The major structural components of protective mucus hydrogels on mucosal surfaces are the secreted polymeric gel-forming mucins. The very high molecular weight and extensive O-glycosylation of gel-forming mucins, which are key to their viscoelastic properties, create problems when studying mucins using conventional biochemical/structural techniques. Thus, key structural information, such as the secondary structure of the various mucin subdomains, and glycosylation patterns along individual molecules, remains to be elucidated. Here, we utilized Raman spectroscopy, Raman optical activity (ROA), circular dichroism (CD), and tip-enhanced Raman spectroscopy (TERS) to study the structure of the secreted polymeric gel-forming mucin MUC5B. ROA indicated that the protein backbone of MUC5B is dominated by unordered conformation, which was found to originate from the heavily glycosylated central mucin domain by isolation of MUC5B O-glycan-rich regions. In sharp contrast, recombinant proteins of the N-terminal region of MUC5B (D1-D2-D′-D3 domains, NT5B), C-terminal region of MUC5B (D4-B-C-CK domains, CT5B) and the Cys-domain (within the central mucin domain of MUC5B) were found to be dominated by the β-sheet. Using these findings, we employed TERS, which combines the chemical specificity of Raman spectroscopy with the spatial resolution of atomic force microscopy to study the secondary structure along 90 nm of an individual MUC5B molecule. Interestingly, the molecule was found to contain a large amount of α-helix/unordered structures and many signatures of glycosylation, pointing to a highly O-glycosylated region on the mucin
bicop: A command for fitting bivariate ordinal regressions with residual dependence characterized by a copula function and normal mixture marginals
In this article, we describe a new Stata command, bicop, for fitting a model consisting of a pair of ordinal regressions with a flexible residual distribution, with each marginal distribution specified as a two-part normal mixture, and stochastic dependence governed by a choice of copula functions. The bicop command generalizes the existing biprobit and bioprobit commands, which assume a bivariate normal residual distribution. We present and explain the bicop estimation command and the available postestimation commands using data on financial well-being from the UK Understanding Society Panel Survey
Understanding Society Innovation Panel Wave 6: results from methodological experiments
This paper presents some preliminary findings from Wave 6 of the Innovation Panel (IP6) of Understanding Society: The UK Household Longitudinal Study. Understanding Society is a major panel survey in the UK. In March 2013, the sixth wave of the Innovation Panel went into the field. IP6 used a mixed-mode design, using on-line interviews and face-to-face interviews. This paper describes the design of IP6, the experiments carried and the preliminary findings from early analysis of the data
Stage-Specific Inhibition of MHC Class I Presentation by the Epstein-Barr Virus BNLF2a Protein during Virus Lytic Cycle
gamma-herpesvirus Epstein-Barr virus (EBV) persists for life in infected individuals despite the presence of a strong immune response. During the lytic cycle of EBV many viral proteins are expressed, potentially allowing virally infected cells to be recognized and eliminated by CD8+ T cells. We have recently identified an immune evasion protein encoded by EBV, BNLF2a, which is expressed in early phase lytic replication and inhibits peptide- and ATP-binding functions of the transporter associated with antigen processing. Ectopic expression of BNLF2a causes decreased surface MHC class I expression and inhibits the presentation of indicator antigens to CD8+ T cells. Here we sought to examine the influence of BNLF2a when expressed naturally during EBV lytic replication. We generated a BNLF2a-deleted recombinant EBV (ΔBNLF2a) and compared the ability of ΔBNLF2a and wild-type EBV-transformed B cell lines to be recognized by CD8+ T cell clones specific for EBV-encoded immediate early, early and late lytic antigens. Epitopes derived from immediate early and early expressed proteins were better recognized when presented by ΔBNLF2a transformed cells compared to wild-type virus transformants. However, recognition of late antigens by CD8+ T cells remained equally poor when presented by both wild-type and ΔBNLF2a cell targets. Analysis of BNLF2a and target protein expression kinetics showed that although BNLF2a is expressed during early phase replication, it is expressed at a time when there is an upregulation of immediate early proteins and initiation of early protein synthesis. Interestingly, BNLF2a protein expression was found to be lost by late lytic cycle yet ΔBNLF2a-transformed cells in late stage replication downregulated surface MHC class I to a similar extent as wild-type EBV-transformed cells. These data show that BNLF2a-mediated expression is stage-specific, affecting presentation of immediate early and early proteins, and that other evasion mechanisms operate later in the lytic cycle
Understanding Society Innovation Panel Wave 11: Results from Methodological Experiments
This is the final version. Available from the University of Essex via the link in this recordThis paper presents some preliminary findings from Wave 11 of the Innovation Panel (IP11) of Understanding Society: The UK Household Longitudinal Study. Understanding Society is a major panel survey in the UK. In May 2018, the eleventh wave of the Innovation Panel went into the field. IP11 used a mixed-mode design, using on-line interviews and face-to-face interviews. This paper describes the design of IP11, the experiments carried and the preliminary findings from early analysis of the data
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