1,389 research outputs found

    Genetic variation within and among asexual populations of Porphyra umbilicalis KĆ¼tzing (Bangiales, Rhodophyta) in the Gulf of Maine, USA

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    The intertidal marine red alga Porphyra umbilicalis reproduces asexually in the Northwest Atlantic. We looked for population substructure among typical open-coastal and atypical estuarine habitats in seven asexual populations of P. umbilicalis from Maine to New Hampshire using eight expressed sequence tag-simple sequence repeats (EST-SSR) or microsatellite loci. Six genotypes were identified, four of which may represent recombinant genotypes from a recombination event that took place locally, or that took place prior to introduction to the Northwest Atlantic. Genotypic diversity was lowest in a population from Wiscasset, Maine, which inhabits an atypical habitat high in the intertidal zone of a bridge piling in an estuarine tidal rapid. Genotypic diversity was highest in the southernmost populations from New Hampshire; we identified two genotypes that were unique to the southernmost populations, and probably represent the most derived genotypes. We looked at genetic distances among populations in similar habitats, and found that populations were more closely related to their closest neighboring population than to a population in a similar habitat. We show that genotypic diversity within P. umbilicalis populations in the Gulf of Maine is relatively high and thus fits a model of high steady-state variation within asexual populations

    Distribution, morphology, and genetic affinities of dwarf embedded Fucus populations from the Northwest Atlantic Ocean

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    Dwarf embedded Fucus populations in the Northwest Atlantic Ocean are restricted to the upper intertidal zone in sandy salt marsh environments; they lack holdfasts and are from attached parental populations of F. spiralis or F. spiralis x F. vesiculosus hybrids after breakage and entanglement with halophytic marsh grasses. Dwarf forms are dichotomously branched, flat, and have a mean overall length and width of 20.3 and 1.3 mm, respectively. Thus, they are longer than Irish (mean 9.3 mm) and Alaskan (mean 15.0 mm) populations identified as F cottonii. Reciprocal transplants of different Fucus taxa in a Maine salt marsh confirm that F spiralis can become transformed into dwarf embedded thalli within the high intertidal zone, while the latter can grow into F. s. ecad lutarius within the mid intertidal zone. Thus, vertical transplantation can modify fucoid morphology and result in varying ecads. Microsatellite markers indicate that attached F spiralis and F vesiculosus are genetically distinct, while dwarf forms may arise via hybridization between the two taxa. The ratio of intermediate to species-specific-genotypes decreased with larger thalli. Also, F s. ecad lutarius consists of a mixture of intermediate and pure genotypes, while dwarf thalli show a greater frequency of hybrids

    Toward a Theory of Public Entrepreneurship

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    This paper explores innovation, experimentation, and creativity in the public domain and in the public interest. Researchers in various disciplines have studied public entrepreneurship, but there is little work in management and economics on the nature, incentives, constraints and boundaries of entrepreneurship directed to public ends. We identify a framework for analyzing public entrepreneurship and its relationship to private entrepreneurial behavior. We submit that public and private entrepreneurship share essential features but differ critically regarding the definition and measurement of objectives, the nature of the selection environment, and the opportunities for rent-seeking. We describe four levels of analysis for studying public entrepreneurship, provide examples, and suggest new research directions.Entrepreneurship, public administration, political economy, institutions, transaction costs

    Resources, Capabilities, and Routines in Public Organization

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    States, state agencies, multilateral agencies, and other non-market actors are relatively under-studied in the strategic entrepreneurship literature. While important contributions examining public decision makers have been made within the agency-theoretic and transaction-cost traditions, there is little research that builds on resource-based, dynamic capabilities, and behavioral approaches to organizations. Yet public organizations can be usefully characterized as stocks of physical, organizational, and human resources; they interact with other organizations in pursuing a type of competitive advantage; they can possess excess capacity, and may grow and diversify in part according to Penrosean (dynamic) capabilities and behavioral logic. Public organizations may be managed as stewards of resources, capabilities, and routines. This paper shows how resource-based, (dynamic) capabilities, and behavioral approaches shed light on the nature and governance of public organizations and suggests a research agenda for public entrepreneurship that reflects insights gained from applying strategic management theory to public organization.

    Toward a Theory of Public Entrepreneurship

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    This paper explores innovation, experimentation, and creativity in the public domain and in the public interest. Researchers in various disciplines have studied public entrepreneurship, but there is little research specifically on the nature, incentives and constraints of public entrepreneurship to innovate in the public interest. We begin by extending concepts of the entrepreneurial firm to include greater interactions in the public domain, and then turn to the role of entrepreneurial firms in fostering institutional change. This focus points toward opportunities for integrating transaction-costs, political and international business theories to achieve a more refined institutional theory of firm-government interactions that incorporates entrepreneurial agency as a principal mechanism for innovating in the fulfillment of public and private interests.

    Using PDSAs to Optimize Surgical Screening

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    This poster describes a project that used a patient-centered medical home model to improve cervical cancer screening for patients at Duffy Health Center in Hyannis. Lessons learned include: identifying existing opportunities to provide whole-person care may provide revenue enhancement opportunities; practice workflow tools require user input in their development to be accepted and effective; buy-in from all team members is crucial and it is important for the team to agree on the process; and data collection is essential, along with ongoing quality improvement and practice transformation coaching

    A Salmonella virulence factor activates the NOD1/NOD2 signaling pathway.

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    The invasion-associated type III secretion system (T3SS-1) of Salmonella enterica serotype Typhimurium (S. Typhimurium) activates the transcription factor NF-ĪŗB in tissue culture cells and induces inflammatory responses in animal models through unknown mechanisms. Here we show that bacterial delivery or ectopic expression of SipA, a T3SS-1-translocated protein, led to the activation of the NOD1/NOD2 signaling pathway and consequent RIP2-mediated induction of NF-ĪŗB-dependent inflammatory responses. SipA-mediated activation of NOD1/NOD2 signaling was independent of bacterial invasion in vitro but required an intact T3SS-1. In the mouse colitis model, SipA triggered mucosal inflammation in wild-type mice but not in NOD1/NOD2-deficient mice. These findings implicate SipA-driven activation of the NOD1/NOD2 signaling pathway as a mechanism by which the T3SS-1 induces inflammatory responses in vitro and in vivo

    Real-Time PCR assay for detection and differentiation of Shiga toxin-producing Escherichia coli from clinical samples

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    Timely accurate diagnosis of Shiga toxin-producing Escherichia coli (STEC) infections is important. We evaluated a laboratory-developed real-time PCR (LD-PCR) assay targeting stx(1), stx(2), and rfbE(O157) with 2,386 qualifying stool samples submitted to the microbiology laboratory of a tertiary care pediatric center between July 2011 and December 2013. Broth cultures of PCR-positive samples were tested for Shiga toxins by enzyme immunoassay (EIA) (ImmunoCard STAT! enterohemorrhagic E. coli [EHEC]; Meridian Bioscience) and cultured in attempts to recover both O157 and non-O157 STEC. E. coli O157 and non-O157 STEC were detected in 35 and 18 cases, respectively. Hemolytic uremic syndrome (HUS) occurred in 12 patients (10 infected with STEC O157, one infected with STEC O125ac, and one with PCR evidence of STEC but no resulting isolate). Among the 59 PCR-positive STEC specimens from 53 patients, only 29 (54.7%) of the associated specimens were toxin positive by EIA. LD-PCR differentiated STEC O157 from non-O157 using rfbE(O157), and LD-PCR results prompted successful recovery of E. coli O157 (n = 25) and non-O157 STEC (n = 8) isolates, although the primary cultures and toxin assays were frequently negative. A rapid ā€œmegaā€-multiplex PCR (FilmArray gastrointestinal panel; BioFire Diagnostics) was used retrospectively, and results correlated with LD-PCR findings in 25 (89%) of the 28 sorbitol-MacConkey agar culture-negative STEC cases. These findings demonstrate that PCR is more sensitive than EIA and/or culture and distinguishes between O157 and non-O157 STEC in clinical samples and that E. coli O157:H7 remains the predominant cause of HUS in our institution. PCR is highly recommended for rapid diagnosis of pediatric STEC infections

    Early and Highly Suppressive ART are Main Factors Associated with Low Viral Reservoir in European Perinatally HIV Infected Children

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    Abstract BACKGROUND: Future strategies aiming to achieve HIV-1 remission are likely to target individuals with small reservoir size. SETTING: We retrospectively investigated factors associated with HIV-1 DNA levels in European, perinatally HIV-infected children starting ART <6 months of age. METHODS: Total HIV-1 DNA was measured from 51 long-term suppressed children 6.3 years (median) after initial viral suppression. Factors associated with log10 total HIV-1 DNA were analyzed using linear regression. RESULTS: At ART initiation, children were aged median [IQR] 2.3 [1.2,4.1] months, CD4% 37 [24,45] %, CD8% 28 [18,36] %, log10 plasma viral load (VL) 5.4 [4.4,5.9] copies/ml. Time to viral suppression was 7.98 [4.6,19.3] months. Following suppression, 13 (25%) children had suboptimal response [ 652 consecutive VL50-400 followed by VL<50] and/or experienced periods of virological failure [ 652 consecutive VL 65400 followed by VL<50]. Median total HIV-1 DNA was 43 [6,195] copies/10 PBMC.Younger age at therapy initiation was associated with lower total HIV-1 DNA (adjusted coefficient [AC] 0.12 per month older, p=0.0091), with a month increase in age at ART start being associated with a 13% increase in HIV DNA. Similarly, a higher proportion of time spent virally suppressed (AC 0.10 per 10% higher, p=0.0022) and absence of viral failure/suboptimal response (AC 0.34 for those with fail/ suboptimal response, p=0.0483) were associated with lower total HIV-1 DNA. CONCLUSION: Early ART initiation and a higher proportion of time suppressed are linked with lower total HIV-1 DNA. Early ART start and improving adherence in perinatally HIV-1 infected children minimize the size of viral reservoir.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial License 4.0 (CCBY-NC), where it is permissible to download, share, remix, transform, and buildup the work provided it is properly cited. The work cannot be used commercially without permission from the journal
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