1,365 research outputs found
Estimating Sustainable Harvests Of Eastern Oysters, Crassostrea Virginica
Sustainability of a fishery is traditionally and typically considered achieved if the exploited population does not decline in numbers or biomass over time as a result of fishing relative to biological reference point goals. Oysters, however, exhibit atypical population dynamics compared with many other commercial species. The population dynamics often display extreme natural interannual variation in numbers and biomass, and oysters create their own habitat-the reef itself. With the worldwide decline of oyster reef habitat and the oyster fisheries dependent thereon, the maintenance of shell has received renewed attention as essential to population sustainability. We apply a shell budget model to estimate the sustainable catch of oysters on public oyster grounds in Louisiana using no net shell loss as a sustainability reference point. Oyster density and size are obtained from an annual stock assessment. The model simulates oyster growth and mortality, and natural shell loss. Shell mass is increased when oysters die in place, and is diminished when oysters are removed by fishing. The shell budget model has practical applications, such as identifying areas for closure, determining total allowable catch, managing shell planting and reef restoration, and achieving product certification for sustainability. The determination of sustainable yield by shell budget modeling should be broadly applicable to the eastern oyster across its entire range
Two Major Autoantibody Clusters in Systemic Lupus Erythematosus
Systemic lupus erythematosus is a chronic autoimmune disease of complex clinical presentation and etiology and is likely influenced by numerous genetic and environmental factors. While a large number of susceptibility genes have been identified, the production of antibodies against a distinct subset of nuclear proteins remains a primary distinguishing characteristic in disease diagnosis. However, the utility of autoantibody biomarkers for disease sub-classification and grouping remains elusive, in part, because of the difficulty in large scale profiling using a uniform, quantitative platform. In the present study serological profiles of several known SLE antigens, including Sm-D3, RNP-A, RNP-70k, Ro52, Ro60, and La, as well as other cytokine and neuronal antigens were obtained using the luciferase immunoprecipitation systems (LIPS) approach. The resulting autoantibody profiles revealed that 88% of a pilot cohort and 98% of a second independent cohort segregated into one of two distinct clusters defined by autoantibodies against Sm/anti-RNP or Ro/La autoantigens, proteins often involved in RNA binding activities. The Sm/RNP cluster was associated with a higher prevalence of serositis in comparison to the Ro/La cluster (P = 0.0022). However, from the available clinical information, no other clinical characteristics were associated with either cluster. In contrast, evaluation of autoantibodies on an individual basis revealed an association between anti-Sm (P = 0.006), RNP-A (P = 0.018) and RNP-70k (P = 0.010) autoantibodies and mucocutaneous symptoms and between anti-RNP-70k and musculoskeletal manifestations (P = 0.059). Serologically active, but clinically quiescent disease also had a higher prevalence of anti-IFN-α autoantibodies. Based on our findings that most SLE patients belong to either a Sm/RNP or Ro/La autoantigen cluster, these results suggest the possibility that alterations in RNA-RNA-binding protein interactions may play a critical role in triggering and/or the pathogenesis of SLE
A New Preconditioning Approachfor an Interior Point–Proximal Method of Multipliers for Linear and Convex Quadratic Programming
In this paper, we address the efficient numerical solution of linear and
quadratic programming problems, often of large scale. With this aim, we devise
an infeasible interior point method, blended with the proximal method of
multipliers, which in turn results in a primal-dual regularized interior point
method. Application of this method gives rise to a sequence of increasingly
ill-conditioned linear systems which cannot always be solved by factorization
methods, due to memory and CPU time restrictions. We propose a novel
preconditioning strategy which is based on a suitable sparsification of the
normal equations matrix in the linear case, and also constitutes the foundation
of a block-diagonal preconditioner to accelerate MINRES for linear systems
arising from the solution of general quadratic programming problems. Numerical
results for a range of test problems demonstrate the robustness of the proposed
preconditioning strategy, together with its ability to solve linear systems of
very large dimension
Receptor protein tyrosine phosphatases are novel components of the polycystin complex
Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutation of PKD1 and PKD2 that encode polycystin-1 and polycystin-2. Polycystin-1 is tyrosine phosphorylated and modulates multiple signaling pathways including AP-1, and the identity of the phosphatases regulating polycystin-1 are previously uncharacterized. Here we identify members of the LAR protein tyrosine phosphatase (RPTP) superfamily as members of the polycystin-1complex mediated through extra- and intracellular interactions. The first extracellular PKD1 domain of polycystin-1 interacts with the first Ig domain of RPTPσ, while the polycystin-1 C-terminus of polycystin-1 interacts with the regulatory D2 phosphatase domain of RPTPγ. Additional homo- and heterotypic interactions between RPTPs recruit RPTPδ. The multimeric polycystin protein complex is found localised in cilia. RPTPσ and RPTPδ are also part of a polycystin-1/E-cadherin complex known to be important for early events in adherens junction stabilisation. The interaction between polycystin-1 and RPTPγ is disrupted in ADPKD cells, while RPTPσ and RPTPδ remain closely associated with E-cadherin, largely in an intracellular location. The polycystin-1 C-terminus is an in vitro substrate of RPTPγ, which dephosphorylates the c-Src phosphorylated Y4237 residue and activates AP1-mediated transcription. The data identify RPTPs as novel interacting partners of the polycystins both in cilia and at adhesion complexes and demonstrate RPTPγ phosphatase activity is central to the molecular mechanisms governing polycystin-dependent signaling. This article is part of a Special Issue entitled: Polycystic Kidney Disease
The SABRTooth feasibility trial protocol: a study to determine the feasibility and acceptability of conducting a phase III randomised controlled trial comparing stereotactic ablative radiotherapy (SABR) with surgery in patients with peripheral stage I non-small cell lung cancer (NSCLC) considered to be at higher risk of complications from surgical resection.
Background Stage I non-small cell lung cancer (NSCLC) is potentially curable, and surgery is considered to be the standard of care for patients with good performance status and minimal co-morbidity. However, a significant proportion of patients with stage I NSCLC have a poorer performance status and significant medical co-morbidity that make them at higher risk of morbidity and mortality from surgery. Stereotactic ablative radiotherapy (SABR), which uses modern radiotherapeutic techniques to deliver large doses of radiation, has shown superiority over conventional radiotherapy in terms of local control and toxicity and is a standard of care for patients with stage I NSCLC who are at too high risk for surgery. However, it is not known whether surgery or SABR is the most effective in patients with stage I NSCLC who are suitable for surgery but are less fit and at higher risk surgical complications. Previous randomised studies have failed to recruit in this setting, and therefore, a feasibility study is required to see whether a full randomised control trial would be possible. Methods/design SABRTooth is a UK-based, multi-centre, open-label, two-group individually (1:1) randomised controlled feasibility study in patients with peripheral stage I NSCLC considered to be at higher risk from surgical resection. The study will assess the feasibility of conducting a definitive large-scale phase III trial. The primary objective is to assess recruitment rates to provide evidence that, when scaled up, recruitment to a large phase III trial would be possible; the target recruitment being 54 patients in total, over a 21-month period. There are multiple secondary and exploratory objectives designed to explore the optimum recruitment and data collection strategies to help optimise the design of a future phase III trial. Discussion To know whether SABR is a better, equivalent or inferior alternative to surgery for higher risk patients is a key question in lung cancer. Other studies comparing SABR to surgery have closed early due to poor recruitment, and therefore, the SABRTooth feasibility study has been designed around the UK National Health Service (NHS) cancer pathway incorporating many design features in order to maximise recruitment for a future definitive phase III trial
19F labelled glycosaminoglycan probes for solution NMR and non-linear (CARS) microscopy
Studying polysaccharide-protein interactions under physiological conditions by conventional techniques is challenging. Ideally, macromolecules could be followed by both in vitro spectroscopy experiments as well as in tissues using microscopy, to enable a proper comparison of results over these different scales but, often, this is not feasible. The cell surface and extracellular matrix polysaccharides, glycosaminoglycans (GAGs) lack groups that can be detected selectively in the biological milieu. The introduction of 19F labels into GAG polysaccharides is explored and the interaction of a labelled GAG with the
heparin-binding protein, antithrombin, employing 19F NMR spectroscopy is followed.
Furthermore, the ability of 19F labelled GAGs to be imaged using CARS microscopy is demonstrated. 19F labelled GAGs enable both 19F NMR protein-GAG binding studies in solution at the molecular level and non-linear microscopy at a microscopic scale to be conducted on the same material, essentially free of background signals
Distribution of coronal and root caries experience among persons aged 60+ in South Australia
The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.This report provides epidemiological data describing caries experience among the population of non-institutionalized older adults in Adelaide and Mt Gambier. Subjects were selected in a stratified random sample of persons aged 60+ who were listed on the South Australian Electoral Database. Oral examinations were conducted by four calibrated dentists among 853 dentate persons aged 60 years and over. There was an average of 14.7 missing teeth, 8.3 filled teeth and 0.3 decayed teeth, and a further 0.2 teeth were present as retained roots. The mean number of missing teeth was higher (p < 0.05) in older compared with younger age groups, and in Mt Gambier compared with Adelaide. The mean DFS of 22.1 was significantly higher (p < 0.05) among younger persons, females and in Adelaide. Root surface caries affected an average of 3.1 surfaces, and was greater (p < 0.05) among persons aged 70-79 years, males and Adelaide residents. However, when root caries was expressed as an attack rate per 100 exposed surfaces, differences were statistically significant only among age groups. Analysis of specific teeth revealed that no more than 40 per cent of molars were retained, and between 30 and 58 per cent of retained molars had coronal fillings.Gary D. Slade, A. John Spence
Rayleigh-Taylor and Richtmyer-Meshkov instabilities: A journey through scales
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordHydrodynamic instabilities such as Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities usually appear
in conjunction with the Kelvin-Helmholtz (KH) instability and are found in many natural phenomenon and engineering applications. They frequently result in turbulent mixing, which has a major impact on the overall flow development
and other effective material properties. This can either be a desired outcome, an unwelcome side effect, or just an unavoidable consequence, but must in all cases be characterized in any model. The RT instability occurs at an interface
between different fluids, when the light fluid is accelerated into the heavy. The RM instability may be considered a
special case of the RT instability, when the acceleration provided is impulsive in nature such as that resulting from a
shock wave. In this pedagogical review, we provide an extensive survey of the applications and examples where such
instabilities play a central role. First, fundamental aspects of the instabilities are reviewed including the underlying
flow physics at different stages of development, followed by an overview of analytical models describing the linear,
nonlinear and fully turbulent stages. RT and RM instabilities pose special challenges to numerical modeling, due to
the requirement that the sharp interface separating the fluids be captured with fidelity. These challenges are discussed
at length here, followed by a summary of the significant progress in recent years in addressing them. Examples of
the pivotal roles played by the instabilities in applications are given in the context of solar prominences, ionospheric
flows in space, supernovae, inertial fusion and pulsed-power experiments, pulsed detonation engines and scramjets.
Progress in our understanding of special cases of RT/RM instabilities is reviewed, including the effects of material
strength, chemical reactions, magnetic fields, as well as the roles the instabilities play in ejecta formation and transport, and explosively expanding flows. The article is addressed to a broad audience, but with particular attention to
graduate students and researchers that are interested in the state-of-the-art in our understanding of the instabilities and
the unique issues they present in the applications in which they are prominent.Science and Technology Facilities CouncilScience and Technology Facilities Counci
Potential conservation of circadian clock proteins in the phylum Nematoda as revealed by bioinformatic searches
Although several circadian rhythms have been described in C. elegans, its molecular clock remains elusive. In this work we employed a novel bioinformatic approach, applying probabilistic methodologies, to search for circadian clock proteins of several of the best studied circadian model organisms of different taxa (Mus musculus, Drosophila melanogaster, Neurospora crassa, Arabidopsis thaliana and Synechoccocus elongatus) in the proteomes of C. elegans and other members of the phylum Nematoda. With this approach we found that the Nematoda contain proteins most related to the core and accessory proteins of the insect and mammalian clocks, which provide new insights into the nematode clock and the evolution of the circadian system.Fil: Romanowski, Andrés. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones BioquÃmicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones BioquÃmicas de Buenos Aires; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de CronobiologÃa; ArgentinaFil: Garavaglia, MatÃas Javier. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Goya, MarÃa Eugenia. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de CronobiologÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Ghiringhelli, Pablo Daniel. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Golombek, Diego Andres. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologÃa. Laboratorio de CronobiologÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Sometimes You Cannot Have It All: Party Switching and Affiliation Motivations as Substitutes
Existing research on when legislators switch parties reports inconsistent results about motivations for switching (e.g., office, ideology, and votes). I treat the motivations for party switching as substitutes and argue that many of the inconsistencies that persist can be explained by modelling the interactive effects between these motivations. For example, scholars differ in terms of whether they find that electoral considerations are an important determinant of party switching. The conflicting findings on the independent effects of electoral considerations are explained here by demonstrating that these effects are conditional on the level of office benefits a legislators enjoys, as well as the ideological distance between the legislator and party. More generally, the empirical analysis provides strong support for the substitution effect hypothesis. Thus, modelling interactive effects increases our understanding of party switching
- …