14,452 research outputs found

    Orthogonal polynomials for area-type measures and image recovery

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    Let GG be a finite union of disjoint and bounded Jordan domains in the complex plane, let K\mathcal{K} be a compact subset of GG and consider the set GG^\star obtained from GG by removing K\mathcal{K}; i.e., G:=GKG^\star:=G\setminus \mathcal{K}. We refer to GG as an archipelago and GG^\star as an archipelago with lakes. Denote by {pn(G,z)}n=0\{p_n(G,z)\}_{n=0}^\infty and {pn(G,z)}n=0\{p_n(G^\star,z)\}_{n=0}^\infty, the sequences of the Bergman polynomials associated with GG and GG^\star, respectively; that is, the orthonormal polynomials with respect to the area measure on GG and GG^\star. The purpose of the paper is to show that pn(G,z)p_n(G,z) and pn(G,z)p_n(G^\star,z) have comparable asymptotic properties, thereby demonstrating that the asymptotic properties of the Bergman polynomials for GG^\star are determined by the boundary of GG. As a consequence we can analyze certain asymptotic properties of pn(G,z)p_n(G^\star,z) by using the corresponding results for pn(G,z)p_n(G,z), which were obtained in a recent work by B. Gustafsson, M. Putinar, and two of the present authors. The results lead to a reconstruction algorithm for recovering the shape of an archipelago with lakes from a partial set of its complex moments.Comment: 24 pages, 9 figure

    Benthic oxygen exchange in a live coralline algal bed and an adjacent sandy habitat: an eddy covariance study

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    Coralline algal (maerl) beds are widespread, slow-growing, structurally complex perennial habitats that support high biodiversity, yet are significantly understudied compared to seagrass beds or kelp forests. We present the first eddy covariance (EC) study on a live maerl bed, assessing the community benthic gross primary productivity (GPP), respiration (R), and net ecosystem metabolism (NEM) derived from diel EC time series collected during 5 seasonal measurement campaigns in temperate Loch Sween, Scotland. Measurements were also carried out at an adjacent (~20 m distant) permeable sandy habitat. The O2 exchange rate was highly dynamic, driven by light availability and the ambient tidally-driven flow velocity. Linear relationships between the EC O2 fluxes and available light indicate that the benthic phototrophic communities were lightlimited. Compensation irradiance (Ec) varied seasonally and was typically ~1.8-fold lower at the maerl bed compared to the sand. Substantial GPP was evident at both sites; however, the maerl bed and the sand habitat were net heterotrophic during each sampling campaign. Additional inputs of ~4 and ~7 mol m-2 yr-1 of carbon at the maerl bed and sand site, respectively, were required to sustain the benthic O2 demand. Thus, the 2 benthic habitats efficiently entrap organic carbon and are sinks of organic material in the coastal zone. Parallel deployment of 0.1 m2 benthic chambers during nighttime revealed O2 uptake rates that varied by up to ~8-fold between replicate chambers (from -0.4 to -3.0 mmol O2 m-2 h-1; n = 4). However, despite extensive O2 flux variability on meter horizontal scales, mean rates of O2 uptake as resolved in parallel by chambers and EC were typically within 20% of one another

    Wireless Audience Response System: Does It Make a Difference?

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    Because Extension seminars are costly in preparation and delivery, questions about the costs and effectiveness of various methods are important to consider. Interactive devices are becoming increasingly available to Extension professionals. One such device, OptionFinder®, utilizes individual wireless remote keypads and a control station, manned by the lecturer or an assistant. It is believed to increase audience participation and information retention. The lecturer can assess the audiences\u27 understanding within seconds by asking multiple choice or true/false questions. The study described here examined the cost and value, in terms of knowledge retention, of such a system compared with other workshop methods

    Role of the complement components C5 and C3a in a mouse model of myocardial ischemia and reperfusion injury

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    Objective: Ischemic heart disease is the leading cause of death worldwide. The complement system plays a major role in inflammation and tissue injury following myocardial ischemia and reperfusion (MI/R) injury. Systemic C5 inhibition in clinical studies has resulted in mixed results and the role of earlier complement components (e.g., C3a), upstream from C5 cleavage, has not been elucidated for MI/R injury. Therefore, we evaluated the role of C5 or C3a in a mouse model of MI/R injury

    Isoenzyme Loci in Brown Trout (Salmo Trutta L.) - Detection and Interpretation from Population Data

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    Previously reported results on natural populations of brown trout (Salmo trutta L.) urged further studies using additional electrophoretically detectable loci. Samples of brain, eye, heart, kidney, liver, and muscle from approximately 50 specimens from each of two populations and a large number of muscle samples from several additional populations were examined. Electrophoretic and staining methods for the 37 enzymes studied are given in detail. Of a total of 69 loci detected, 54 loci were considered usable in population genetics screenings. The expression of the loci coding for these enzymes is described and interpreted. The results presented will serve as a basis for a more detailed examination of genetic variation in brown trout populations

    HIV-1 envelope protein gp41: An NMR study of dodecyl phosphocholine embedded gp41 reveals a dynamic prefusion intermediate conformation.

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    Human immunodeficiency viral (HIV-1) fusion is mediated by the viral envelope gp120/gp41 complex (ENVelope glycoprotein). After gp120 shedding, gp41 is exposed and elicits membrane fusion via a cascade of conformational changes. In contrast to prefusion and postfusion conformation, little is known about any intermediate conformation. We report on a solution NMR investigation of homotrimeric HIV-1 gp4127–194, comprising the transmembrane region and reconstituted in dodecyl phosphocholine (DPC) micelles. The protein is mainly α-helical, but experiences internal dynamics on the nanosecond and micro to millisecond time scale and transient α-helical behavior for certain residues in the N-terminal heptad repeat (NHR). Strong lipid interactions are observed, in particular for C-terminal residues of the NHR and imunodominant loop region connecting NHR and C-terminal heptad repeat (CHR). Our data indicate an extended conformation with features anticipated for a prefusion intermediate, presumably in exchange with a lowly populated postfusion six-helical bundle conformation

    Telemedicine and Primary Care Obesity Management in Rural Areas– Innovative Approach for Older Adults?

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    Background: The growing prevalence of obesity is paralleling a rise in the older adult population creating an increased risk of functional impairment, nursing home placement and early mortality. The Centers for Medicare and Medicaid recognized the importance of treating obesity and instituted a benefit in primary care settings to encourage intensive behavioral therapy in beneficiaries by primary care clinicians. This benefit covers frequent, brief, clinic visits designed to address older adult obesity. Discussion: We describe the challenges in the implementation and delivery into real-world settings. The challenges in rural settings that have the fastest growing elderly population, high obesity rates, but also workforce shortages and lack of specialized services are emphasized. The use of Telemedicine has successfully been implemented in other specialties and could be a useful modality in delivering much needed intensive behavioral therapy, particularly in distant, under-resourced environments. This review outlines some of the challenges with the current benefit and proposed solutions in overcoming rural primary care barriers to implementation, including changes in staffing models. Conclusions: Recommendations to extend the benefit’s coverage to be more inclusive of non-physician team members is needed but also for improvement in reimbursement for telemedicine services for older adults with obesity

    A price of service in a compositional SOA framework

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