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Showing papers by "University of Warwick published in 2005"


Journal ArticleDOI
TL;DR: A variety of methods are described that allow the mixing network, or an approximation to the network, to be ascertained and how the two fields of network theory and epidemiological modelling can deliver an improved understanding of disease dynamics and better public health through effective disease control are suggested.
Abstract: Networks and the epidemiology of directly transmitted infectious diseases are fundamentally linked. The foundations of epidemiology and early epidemiological models were based on population wide random-mixing, but in practice each individual has a finite set of contacts to whom they can pass infection; the ensemble of all such contacts forms a ‘mixing network’. Knowledge of the structure of the network allows models to compute the epidemic dynamics at the population scale from the individual-level behaviour of infections. Therefore, characteristics of mixing networks—and how these deviate from the random-mixing norm—have become important applied concerns that may enhance the understanding and prediction of epidemic patterns and intervention measures. Here, we review the basis of epidemiological theory (based on random-mixing models) and network theory (based on work from the social sciences and graph theory). We then describe a variety of methods that allow the mixing network, or an approximation to the network, to be ascertained. It is often the case that time and resources limit our ability to accurately find all connections within a network, and hence a generic understanding of the relationship between network structure and disease dynamics is needed. Therefore, we review some of the variety of idealized network types and approximation techniques that have been utilized to elucidate this link. Finally, we look to the future to suggest how the two fields of network theory and epidemiological modelling can deliver an improved understanding of disease dynamics and better public health through effective disease control.

1,737 citations


Journal ArticleDOI
TL;DR: It is possible that fall‐prevention strategies have limited effect on falls that result in injuries or are ineffective in populations who are at a higher risk of injury.
Abstract: The prevention of injury associated with falls in older people is a public health target in many countries around the world. Although there is good evidence that interventions such as multifactorial fall prevention and individually prescribed exercise are effective in reducing falls, the effect on serious injury rates is unclear. Historically, trials have not been adequately powered to detect injury endpoints, and variations in case definition across trials have hindered meta-analysis. It is possible that fall-prevention strategies have limited effect on falls that result in injuries or are ineffective in populations who are at a higher risk of injury. Further research is required to determine whether fall-prevention interventions can reduce serious injuries. Prevention of Falls Network Europe (ProFaNE) is a collaborative project to reduce the burden of fall injury in older people through excellence in research and promotion of best practice (www.profane.eu.org). The European Commission funds the network, which links clinicians, members of the public, and researchers worldwide. The aims are to identify major gaps in knowledge in fall injury prevention and to facilitate the collaboration necessary for large-scale clinical research activity, including clinical trials, comparative research, and prospective meta-analysis. Work is being undertaken in a 4-year program. As a first step, the development of a common set of outcome definitions and measures for future trials or meta-analysis was considered.

1,725 citations


Journal ArticleDOI
22 Jul 2005-Science
TL;DR: It is shown that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle, which explains why plants gain advantage from circadian control.
Abstract: Circadian clocks are believed to confer an advantage to plants, but the nature of that advantage has been unknown. We show that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle. In wild type and in long- and short-circadian period mutants of Arabidopsis thaliana, plants with a clock period matched to the environment contain more chlorophyll, fix more carbon, grow faster, and survive better than plants with circadian periods differing from their environment. This explains why plants gain advantage from circadian control.

1,276 citations


Journal ArticleDOI
TL;DR: It is theorized that multi-professionalization shapes "nonspread," which helps explain barriers to the spread of innovation in multiprofessional organizations in both health care and other settings.
Abstract: Two qualitative studies in the U.K. health care sector trace eight purposefully selected innovations. Complex, contested, and nonlinear innovation careers emerged. Developing the nonlinear perspective on innovation spread further, we theorize that multi-professionalization shapes "nonspread." Social and cognitive boundaries between different professions retard spread, as individual professionals operate within unidisciplinary communities of practice. This new theory helps explain barriers to the spread of innovation in multiprofessional organizations in both health care and other settings.

979 citations


Journal ArticleDOI
TL;DR: In this article, an analysis of changes in global gene expression patterns during developmental leaf senescence in Arabidopsis has identified more than 800 genes that show a reproducible increase in transcript abundance.
Abstract: An analysis of changes in global gene expression patterns during developmental leaf senescence in Arabidopsis has identified more than 800 genes that show a reproducible increase in transcript abundance. This extensive change illustrates the dramatic alterations in cell metabolism that underpin the developmental transition from a photosynthetically active leaf to a senescing organ which functions as a source of mobilizable nutrients. Comparison of changes in gene expression patterns during natural leaf senescence with those identified, when senescence is artificially induced in leaves induced to senesce by darkness or during sucrose starvation-induced senescence in cell suspension cultures, has shown not only similarities but also considerable differences. The data suggest that alternative pathways for essential metabolic processes such as nitrogen mobilization are used in different senescent systems. Gene expression patterns in the senescent cell suspension cultures are more similar to those for dark-induced senescence and this may be a consequence of sugar starvation in both tissues. Gene expression analysis in senescing leaves of plant lines defective in signalling pathways involving salicylic acid (SA), jasmonic acid (JA) and ethylene has shown that these three pathways are all required for expression of many genes during developmental senescence. The JA/ethylene pathways also appear to operate in regulating gene expression in dark-induced and cell suspension senescence whereas the SA pathway is not involved. The importance of the SA pathway in the senescence process is illustrated by the discovery that developmental leaf senescence, but not dark-induced senescence, is delayed in plants defective in the SA pathway.

952 citations


Journal ArticleDOI
TL;DR: There is considerable genetic variation in crop species that can be harnessed for sustainable biofortification strategies, and new genotypes with higher mineral densities are being developed.

861 citations


Journal ArticleDOI
TL;DR: A positive psychological theory of growth through adversity is proposed in this article, which posits an intrinsic motivation toward growth, showing how this motivation can be expressed in an organismic valuing theory.
Abstract: A positive psychological theory of growth through adversity is proposed. The organismic valuing theory of growth through adversity posits an intrinsic motivation toward growth, showing how this lea...

771 citations


Book
01 Jan 2005
TL;DR: In this paper, a Reformed Neo-institutionalist Research Programme (RNRP) is proposed for the analysis of institutional governance and innovation and a Strategy for the Analysis of Institutional Governance and innovation.
Abstract: 1. Neo-Institutional Analysis and Comparative Capitalism 2. Typologies of Capitalism 3. Wahlverwandschaft, Complementarity, and the Theoretical Utlitity of Institutional Untidiness 4. Innovation and Path Dependence 5. A Strategy for the Analysis of Institutional Governance and innovation 6. Recombinant Governance Mechanisms: Cases 7. Conclusions: A Reformed Neo-institutionalist Research Programme

691 citations


Journal ArticleDOI
TL;DR: Analytical methods are used to show that ignoring the latent period or making the common assumption of exponentially distributed latent and infectious periods always results in underestimating the basic reproductive ratio of an infection from outbreak data.
Abstract: Background Mathematical models have become invaluable management tools for epidemiologists, both shedding light on the mechanisms underlying observed dynamics as well as making quantitative predictions on the effectiveness of different control measures. Here, we explain how substantial biases are introduced by two important, yet largely ignored, assumptions at the core of the vast majority of such models. Methods and Findings First, we use analytical methods to show that (i) ignoring the latent period or (ii) making the common assumption of exponentially distributed latent and infectious periods (when including the latent period) always results in underestimating the basic reproductive ratio of an infection from outbreak data. We then proceed to illustrate these points by fitting epidemic models to data from an influenza outbreak. Finally, we document how such unrealistic a priori assumptions concerning model structure give rise to systematically overoptimistic predictions on the outcome of potential management options. Conclusion This work aims to highlight that, when developing models for public health use, we need to pay careful attention to the intrinsic assumptions embedded within classical frameworks.

565 citations


Journal ArticleDOI
TL;DR: In this article, the authors explore the question of whether the "corona" and "jet base" are in fact related, starting by testing the strongest premise that they are synonymous, and compare the results to simultaneous radio/X-ray data obtained from the hard states of the Galactic XRBs GX 339-4 and Cygnus X-1.
Abstract: The hard state of X-ray binaries (XRBs) is characterized by a power-law spectrum in the X-ray band and a flat/inverted radio/IR spectrum associated with occasionally imaged compact jets. It has generally been thought that the hard X-rays result from Compton upscattering of thermal accretion disk photons by a hot, coronal plasma whose properties are inferred via spectral fitting. Interestingly, these properties—especially those from certain magnetized corona models—are very similar to the derived plasma conditions at the jet footpoints. Here we explore the question of whether the "corona" and "jet base" are in fact related, starting by testing the strongest premise that they are synonymous. In such models, the radio through the soft X-rays are dominated by synchrotron emission, while the hard X-rays are dominated by inverse Compton at the jet base—with both disk and synchrotron photons acting as seed photons. The conditions at the jet base fix the conditions along the rest of the jet, thus creating a direct link between the X-ray and radio emission. We also add to this model a simple iron line and convolve the spectrum with neutral reflection. After forward-folding the predicted spectra through the detector response functions, we compare the results to simultaneous radio/X-ray data obtained from the hard states of the Galactic XRBs GX 339-4 and Cygnus X-1. Results from simple Compton corona model fits are also presented for comparison. We demonstrate that the jet model fits are statistically as good as the single-component corona model X-ray fits, yet are also able to address the simultaneous radio data.

564 citations


Journal ArticleDOI
TL;DR: DNA and rRNA are the most informative taxonomic biomarkers and 13C-labelled molecules can be purified from unlabelled nucleic acid by density-gradient centrifugation.
Abstract: Stable isotope probing (SIP) is a technique that is used to identify the microorganisms in environmental samples that use a particular growth substrate. The method relies on the incorporation of a substrate that is highly enriched in a stable isotope, such as (13)C, and the identification of active microorganisms by the selective recovery and analysis of isotope-enriched cellular components. DNA and rRNA are the most informative taxonomic biomarkers and (13)C-labelled molecules can be purified from unlabelled nucleic acid by density-gradient centrifugation. The future holds great promise for SIP, particularly when combined with other emerging technologies such as microarrays and metagenomics.

Journal ArticleDOI
TL;DR: The results suggest that human-related issues, such as rapport and transactive memory, were important for collaborative work in the teams studied and suggested a practical guide to enhance collaborativeWork in globally distributed teams.
Abstract: Traditionally, the main focus of the information system (IS) literature has been on technical aspects related to system development projects. Furthermore, research in the IS field has mainly focused on co-located project teams. In this respect, social aspects involved in IS projects were neglected or scarcely reported. To fill this gap, this paper studies the contribution of social ties and knowledge sharing to successful collaboration in distributed IS development teams. Data were drawn from two successful globally distributed system development projects at SAP and LeCrov. Data collected were codified using Atlas.ti software. The results suggest that human-related issues, such as rapport and transactive memory, were important for collaborative work in the teams studied. The paper concludes by discussing the implications for theory and suggesting a practical guide to enhance collaborative work in globally distributed teams.

Journal ArticleDOI
TL;DR: Overall the general rhizosphere effect could help the plant by maintaining the recycling of nutrients, through the production of hormones, helping to provide resistance to microbial diseases and to aid tolerance to toxic compounds.
Abstract: This review looks briefly at plants and their rhizosphere microbes, the chemical communications that exist, and the biological processes they sustain. Primarily it is the loss of carbon compounds from roots that drives the development of enhanced microbial populations in the rhizosphere when compared with the bulk soil, or that sustains specific mycorrhizal or legume associations. The benefits to the plant from this carbon loss are discussed. Overall the general rhizosphere effect could help the plant by maintaining the recycling of nutrients, through the production of hormones, helping to provide resistance to microbial diseases and to aid tolerance to toxic compounds. When plants lack essential mineral elements such as P or N, symbiotic relationships can be beneficial and promote plant growth. However, this benefit may be lost in well-fertilized (agricultural) soils where nutrients are readily available to plants and symbionts reduce growth. Since these rhizosphere associations are commonplace and offer key benefits to plants, these interactions would appear to be essential to their overall success.

Journal ArticleDOI
07 Jul 2005-Nature
TL;DR: It is shown that an increase in pCO2 in the arterial blood triggers the immediate release of ATP from three chemosensitive regions located on the ventral surface of the medulla oblongata, suggesting that ATP release constitutes a key step in central chemosensory transduction.
Abstract: Extracellular signalling by the purine nucleotide ATP has long been associated with sensory function. In the periphery, ATP mediates nociception, mechanosensitivity, thermal sensitivity and O2 chemosensitivity. These processes share a common mechanism that involves the release of ATP to excite afferent fibres via activation of ionotropic P2X and/or metabotropic P2Y receptors. Chemosensors located in the brainstem are crucial for the maintenance of physiological levels of blood gases through the regulation of breathing. Here we show that an increase in pCO2 in the arterial blood triggers the immediate release of ATP from three chemosensitive regions located on the ventral surface of the medulla oblongata. Blockade of ATP receptors at these sites diminishes the chemosensory control of breathing, suggesting that ATP release constitutes a key step in central chemosensory transduction. These new data suggest that ATP, a phylogenetically ancient, unique and simple molecule, has been widely used in the evolution of afferent systems to mediate distinct forms of sensory transduction not only in the periphery but also within the central nervous system.

Journal ArticleDOI
TL;DR: In this paper, the authors simulate IPHAS (r'-Halpha,r'-i') point-source colours using a spectrophotometric library of stellar spectra and available filter transmission profiles.
Abstract: The Isaac Newton Telescope (INT) Photometric Halpha Survey of the Northern Galactic Plane (IPHAS) is a 1800-deg 2 CCD survey of the northern Milky Way spanning the latitude range -5° < b < + 5° and reaching down to r'~= 20 (10sigma). Representative observations and an assessment of point-source data from IPHAS, now underway, are presented. The data obtained are Wide Field Camera images in the Halpha narrow-band, and Sloan r' and i' broad-band filters. We simulate IPHAS (r'-Halpha,r'-i') point-source colours using a spectrophotometric library of stellar spectra and available filter transmission profiles: this defines the expected colour properties of (i) solar metallicity stars, without Halpha emission, and (ii) emission-line stars. Comparisons with observations of fields in Aquila show that the simulations of normal star colours reproduce the observations well for all spectral types earlier than M. A further comparison between colours synthesized from long-slit flux-calibrated spectra and IPHAS photometry for six objects in a Taurus field confirms the reliability of the pipeline calibration. Spectroscopic follow-up of a field in Cepheus shows that sources lying above the main stellar locus in the (r'- Halpha,r'-i') plane are confirmed to be emission-line objects with very few failures. In this same field, examples of Halpha deficit objects (a white dwarf and a carbon star) are shown to be readily distinguished by their IPHAS colours. The role IPHAS can play in studies of spatially resolved northern Galactic nebulae is discussed briefly and illustrated by a continuum-subtracted mosaic image of Shajn 147 (a supernova remnant, 3° in diameter). The final catalogue of IPHAS point sources will contain photometry on about 80 million objects. Used on its own, or in combination with near-infrared photometric catalogues, IPHAS is a major resource for the study of stellar populations making up the disc of the Milky Way. The eventual yield of new northern emission-line objects from IPHAS is likely to be an order of magnitude increase on the number already known.

Journal ArticleDOI
TL;DR: The authors identified 11 empirical studies that reported links between religion, spirituality, and posttraumatic growth, including positive religious coping, religious openness, readiness to face existential questions, religious participation, and intrinsic religiousness.
Abstract: A search of the published literature identified 11 empirical studies that reported links between religion, spirituality, and posttraumatic growth. A review of these 11 studies produced three main findings. First, these studies show that religion and spirituality are usually, although not always, beneficial to people in dealing with the aftermath of trauma. Second, that traumatic experiences can lead to a deepening of religion or spirituality. Third, that positive religious coping, religious openness, readiness to face existential questions, religious participation, and intrinsic religiousness are typically associated with posttraumatic growth. Important directions for future research are suggested that centre on the need for more fine-grained analysis of religion and spirituality variables, together with longitudinal research designs, that allow more detailed exploration of the links between religion, spirituality, and posttraumatic growth.

Journal ArticleDOI
TL;DR: The oomycete Phytophthora infestans causes late blight, the potato disease that precipitated the Irish famines in 1846 and 1847, and it is suggested that Avr3a has undergone gene duplication and that an allele evading recognition by R3a arose under positive selection.
Abstract: The oomycete Phytophthora infestans causes late blight, the potato disease that precipitated the Irish famines in 1846 and 1847. It represents a reemerging threat to potato production and is one of >70 species that are arguably the most devastating pathogens of dicotyledonous plants. Nevertheless, little is known about the molecular bases of pathogenicity in these algae-like organisms or of avirulence molecules that are perceived by host defenses. Disease resistance alleles, products of which recognize corresponding avirulence molecules in the pathogen, have been introgressed into the cultivated potato from a wild species, Solanum demissum, and R1 and R3a have been identified. We used association genetics to identify Avr3a and show that it encodes a protein that is recognized in the host cytoplasm, where it triggers R3a-dependent cell death. Avr3a resides in a region of the P. infestans genome that is colinear with the locus containing avirulence gene ATR1NdWsB in Hyaloperonospora parasitica, an oomycete pathogen of Arabidopsis. Remarkably, distances between conserved genes in these avirulence loci were often similar, despite intervening genomic variation. We suggest that Avr3a has undergone gene duplication and that an allele evading recognition by R3a arose under positive selection.

Posted Content
TL;DR: In this article, the authors developed a model that endogenizes dynamic financing, investment, and cash retention/payout policies in order to analyze the effect of financial flexibility on firm value.
Abstract: We develop a model that endogenizes dynamic financing, investment, and cash retention/payout policies in order to analyze the effect of financial flexibility on firm value. We show that the value of financing flexibility depends on the costs of external financing, the level of corporate and personal tax rates which determine the effective cost of holding cash, the firm's growth potential and its maturity, and the reversibility of capital. Through simulations, we demonstrate that firms that face financing frictions should simultaneously borrow and lend, and we examine the nature of the dynamic debt and liquidity policies and the value associated with corporate liquidity.

Journal ArticleDOI
TL;DR: The objectives were to identify fall‐related psychological outcome measures and to undertake a systematic quality assessment of their key measurement properties, and to establish and compare the instruments' measurement properties.
Abstract: The objectives were to identify fall-related psychological outcome measures and to undertake a systematic quality assessment of their key measurement properties. A Cochrane review of fall-prevention interventions in older adults was used to identify fall-related psychological measurements. PubMed, CINAHL, and PsycINFO were systematically searched to identify instruments not used in trials and papers reporting the methodological quality of relevant measures. Reference lists of articles were searched for additional literature, and researchers were contacted. Two reviewers undertook quality extraction relating to content, population, reliability, validity, responsiveness, practicality, and feasibility. Twenty-five relevant papers were identified. Twenty-three measures met the inclusion criteria: six single-item questions, Falls Efficacy Scale (FES), revised FES, modified FES, FES-UK, Activities-specific Balance and Confidence Scale (ABC), ABC-UK, Confidence in maintaining Balance Scale, Mobility Efficacy Scale, adapted FES, amended FES, Survey of Activities and Fear of Falling in the Elderly (SAFFE), University of Illinois at Chicago Fear of Falling Measure, Concern about Falling Scale, Falls Handicap Inventory, modified SAFFE, Consequences of Falling Scale, and Concern about the Consequences of Falling Scale. There is limited evidence about the measurement properties of single-item measures. Several multiitem measures obtained acceptable reliability and validity, but there is less evidence regarding responsiveness, practicality, and feasibility. Researchers should select measures based on the constructs they intend to study. Further research is needed to establish and compare the instruments' measurement properties.

Journal ArticleDOI
TL;DR: In this paper, a review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves), theoretical modelling of interaction of magnetohydrodynamic (MHD) waves with plasma structures, and implementation of the theoretical results for the mode identification.
Abstract: Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD) wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves), theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

Journal ArticleDOI
TL;DR: The authors review the basic science of chondral injuries, the historical perspective of the available surgical options, and present guidelines for patient evaluation and treatment.
Abstract: Surgical procedures designed to treat focal chondral lesions are evolving and are supported by basic science principles of cartilage physiology and known responses to injury. Selecting the proper treatment algorithm for a particular patient depends on careful patient evaluation, including the recognition of comorbidities such as ligamentous instability, deficient menisci, or malalignment of the mechanical limb axis or extensor mechanism. These comorbidities may need to be treated in conjunction with symptomatic chondral injuries to provide a mutually beneficial effect. A central tenet of cartilage restoration is to leave future treatment options available should they become necessary. In this article (part 1), the authors review the basic science of chondral injuries, the historical perspective of the available surgical options, and present guidelines for patient evaluation and treatment.

Journal ArticleDOI
TL;DR: The cloning of ATR1NdWsB has highlighted the presence of a highly conserved novel amino acid motif in avirulence proteins from three different oomycetes and its similarity to a host-targeting signal from malaria parasites suggest a conserved role in pathogenicity.
Abstract: The perception of downy mildew avirulence (Arabidopsis thaliana Recognized [ATR]) gene products by matching Arabidopsis thaliana resistance (Recognition of Peronospora parasitica [RPP]) gene products triggers localized cell death (a hypersensitive response) in the host plant, and this inhibits pathogen development. The oomycete pathogen, therefore, is under selection pressure to alter the form of these gene products to prevent detection. That the pathogen maintains these genes indicates that they play a positive role in pathogen survival. Despite significant progress in cloning plant RPP genes and characterizing essential plant components of resistance signaling pathways, little progress has been made in identifying the oomycete molecules that trigger them. Concluding a map-based cloning effort, we have identified an avirulence gene, ATR1NdWsB, that is detected by RPP1 from the Arabidopsis accession Niederzenz in the cytoplasm of host plant cells. We report the cloning of six highly divergent alleles of ATR1NdWsB from eight downy mildew isolates and demonstrate that the ATR1NdWsB alleles are differentially recognized by RPP1 genes from two Arabidopsis accessions (Niederzenz and Wassilewskija). RPP1-Nd recognizes a single allele of ATR1NdWsB; RPP1-WsB also detects this allele plus three additional alleles with divergent sequences. The Emco5 isolate expresses an allele of ATR1NdWsB that is recognized by RPP1-WsB, but the isolate evades detection in planta. Although the Cala2 isolate is recognized by RPP1-WsA, the ATR1NdWsB allele from Cala2 is not, demonstrating that RPP1-WsA detects a novel ATR gene product. Cloning of ATR1NdWsB has highlighted the presence of a highly conserved novel amino acid motif in avirulence proteins from three different oomycetes. The presence of the motif in additional secreted proteins from plant pathogenic oomycetes and its similarity to a host-targeting signal from malaria parasites suggest a conserved role in pathogenicity.

Journal ArticleDOI
TL;DR: Analysis of the model predicted the properties of these components, including an acute light induction at dawn that is rapidly repressed by LHY and CCA1, and found this unexpected regulation in RNA levels of the evening‐expressed gene GIGANTEA (GI), supporting the proposed network and making GI a strong candidate for this component.
Abstract: Circadian clocks involve feedback loops that generate rhythmic expression of key genes. Molecular genetic studies in the higher plant Arabidopsis thaliana have revealed a complex clock network. The first part of the network to be identified, a transcriptional feedback loop comprising TIMING OF CAB EXPRESSION 1 (TOC1), LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), fails to account for significant experimental data. We develop an extended model that is based upon a wider range of data and accurately predicts additional experimental results. The model comprises interlocking feedback loops comparable to those identified experimentally in other circadian systems. We propose that each loop receives input signals from light, and that each loop includes a hypothetical component that had not been explicitly identified. Analysis of the model predicted the properties of these components, including an acute light induction at dawn that is rapidly repressed by LHY and CCA1. We found this unexpected regulation in RNA levels of the evening-expressed gene GIGANTEA (GI), supporting our proposed network and making GI a strong candidate for this component.

Journal ArticleDOI
TL;DR: A series of alpha-functional maleimide polymethacrylates prepared via copper-catalyzed living radical polymerization (LRP) have been successfully developed and the polymers obtained in multigram scale, with an 80-100% content of maleimides reactive chain ends, depending on the method employed.
Abstract: A series of alpha-functional maleimide polymethacrylates (M(n) = 4.1-35.4 kDa, PDi = 1.06-1.27) have been prepared via copper-catalyzed living radical polymerization (LRP). Two independent synthetic protocols have been successfully developed and the polymers obtained in multigram scale, with an 80-100% content of maleimide reactive chain ends, depending on the method employed. A method for the synthesis of amino-terminated polymers, starting from Boc-protected amino initiators, has also been developed, as these derivatives are key intermediates in one of the two processes studied in the present work. The alternative synthetic pathway involves an initiator containing a maleimide unit "protected" as a Diels-Alder adduct. After the polymerization step, the maleimide functionality has been reintroduced by retro-Diels-Alder reaction, by simply refluxing those polymers in toluene for 7 h. These maleimido-terminated materials, poly(methoxyPEG((475))) methacrylates and poly(glycerol) methacrylates, differ for both the nature and size of the polymer side branches and showed an excellent solubility in water, a property that made them an ideal candidate for the synthesis of new polymer-(poly)peptide biomaterials. These functional polymers have been successfully employed in conjugation reactions in the presence of thiol-containing model substrates, namely, reduced glutathione (gamma-Glu-Cys-Gly) and the carrier protein, bovine serum albumin (BSA), in 100 mM phosphate buffer (pH 6.8-7.4) and ambient temperature.

Journal ArticleDOI
TL;DR: The differences between mass-action and network-based models are investigated to determine when mass- action models are a reliable tool, and suggest ways in which their behaviour should be refined.

Journal ArticleDOI
TL;DR: The authors propose an alternative relative judgment model (RJM) in which the elemental perceptual units are representations of the differences between current and previous stimuli that are used, together with the previous feedback, to respond.
Abstract: In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative relative judgment model (RJM) in which the elemental perceptual units are representations of the differences between current and previous stimuli. These differences are used, together with the previous feedback, to respond. Without using long-term representations of absolute magnitudes, the RJM accounts for (a) information transmission limits, (b) bowed serial position effects, and (c) sequential effects, where responses are biased toward immediately preceding stimuli but away from more distant stimuli (assimilation and contrast).

Journal ArticleDOI
TL;DR: It is demonstrated that accurate prediction of adenylation domain substrate selectivity is possible and intriguing mechanistic questions regarding the assembly of a tetrapeptide by a trimodular NRPS are raised.
Abstract: Analyses of microbial genome sequences reveal numerous examples of gene clusters encoding proteins typically involved in complex natural product biosynthesis but not associated with the production of known natural products. In Streptomyces coelicolor M145 there are several gene clusters encoding new nonribosomal peptide synthetase (NRPS) systems not associated with known metabolites. Application of structure-based models for substrate recognition by NRPS adenylation domains predicts the amino acids incorporated into the putative peptide products of these systems, but the accuracy of these predictions is untested. Here we report the isolation and structure determination of the new tris-hydroxamate tetrapeptide iron chelator coelichelin from S. coelicolor using a genome mining approach guided by substrate predictions for the trimodular NRPS CchH, and we show that this enzyme, which lacks a C-terminal thioesterase domain, together with a homolog of enterobactin esterase (CchJ), are required for coelichelin biosynthesis. These results demonstrate that accurate prediction of adenylation domain substrate selectivity is possible and raise intriguing mechanistic questions regarding the assembly of a tetrapeptide by a trimodular NRPS.

Journal ArticleDOI
Bernard Aubert1, R. Barate1, D. Boutigny1, F. Couderc1  +601 moreInstitutions (76)
TL;DR: In this article, the decay of B{bar B} events collected at the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric energy storage ring was studied.
Abstract: The authors study the decay B{sup -} {yields} J/{psi}K{sup -}{pi}{sup +}{pi}{sup -} using 117 million B{bar B} events collected at the {Upsilon}(4S) resonance with the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage ring. They measure the branching fractions {Beta}(B{sup -} {yields} J/{psi}K{sup -} {pi}{sup +}{pi}{sup -}) = (116 {+-} 7(stat.) {+-} 9(syst.)) x 10{sup -5} and {Beta}(B{sup -} {yields} X(3872)K{sup -}) x {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) = (1.28 {+-} 0.41) x 10{sup -5} and find the mass of the X(3872) to be 3873.4 {+-} 1.4MeV/c{sup 2}. They search for the h{sub c} narrow state in the decay B{sup -} {yields} h{sub c} K{sup -}, h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -} and for the decay B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}, with D{sup 0} {yields} K{sup -}{pi}{sup +}. They set the 90% C.L. limits {Beta}(B{sup -} {yields} h{sub c}K{sup -}) x {Beta}(h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 3.4 x 10{sup -6} and {Beta}(B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}) < 5.2 x 10{sup -5}.

Journal ArticleDOI
TL;DR: The authors describe entrepreneurship in terms of Lacan's concept of the Real and Slavoj Žižek's notion of the sublime object, and make a case for a continual questioning of the subject, a questioning that is today being foreclosed by those critics who were first to call the subject into question.
Abstract: This paper engages with debates on enterprise culture and one of its key subjects—the entrepreneur. Enlisting the work of Jacques Lacan and Slavoj Žižek, we attempt to explain the continuing failure of entrepreneurship discourse to assign the character of the entrepreneur a positive identity. Shifting away from stable categories such as ‘the entrepreneur’, we describe entrepreneurship in terms of Lacan’s concept of the Real and Žižek’s concept of the sublime object. This allows us to critically scrutinize the operation of the phantasmic category of the entrepreneur. In addition to indicating some prospects for the future of psychoanalytic cultural criticism in organization studies, we make a case for a continual questioning of the subject, a questioning that is today being foreclosed by those critics who were first to call the subject into question.

Journal ArticleDOI
TL;DR: The focus of as mentioned in this paper on the relationship between companies and local communities derives from a concern that many accounts of corporate responsibility and citizenship overlook this relationship, in particular, relations with poorer communities as part of a general neglect of the developmental implications of the CSR agenda.
Abstract: The focus of this article on the relationship between companies and local communities derives from a concern that many accounts of corporate responsibility and citizenship overlook this relationship—in particular, relations with poorer communities—as part of a general neglect of the developmental implications of the CSR agenda. Communities are engaging with corporations more routinely now than previously, a trend fostered by the lowering of barriers to trade through global trade accords, attempts to strengthen the rights of foreign investors and broader processes of national liberalization across many parts of the developing world. Increasingly they do so in ways that assume global significance because of new forms of global organizing and the influence of media and telecommunications, which expose companies’ activities to greater scrutiny, as well as the nature of the claims companies themselves now make about their global operations. While there is a long history of firms in the extractive and plantation sectors, being engaged in conflicts and negotiations with communities, these new factors have exposed many more sectors and regions to these political dynamics. It is often assumed that mechanisms for improving the social and environmental conduct of firms, such as codes of conduct, ethical trading initiatives and certification schemes, provide new forms of protection to poorer groups. However, questions are being asked about the extent and effectiveness of such protection, arising from concerns over whether these tools are sufficiently geared towards the needs of the very poorest workers. Similar anxieties attach to the lack of effective international and national regulation of the private sector, and the inaccessibility and underdevelopment of mechanisms of redress and company liability. 1 The purpose of this article is to add some clarity to the discussion about for whom CSR works and under what conditions.