1,444 research outputs found

    Abnormal infant islet morphology precedes insulin resistance in PCOS-like monkeys.

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    Polycystic ovary syndrome (PCOS) is prevalent in reproductive-aged women and confounded by metabolic morbidities, including insulin resistance and type 2 diabetes. Although the etiology of PCOS is undefined, contribution of prenatal androgen (PA) exposure has been proposed in a rhesus monkey model as premenopausal PA female adults have PCOS-like phenotypes in addition to insulin resistance and decreased glucose tolerance. PA female infants exhibit relative hyperinsulinemia, suggesting prenatal sequelae of androgen excess on glucose metabolism and an antecedent to future metabolic disease. We assessed consequences of PA exposure on pancreatic islet morphology to identify evidence of programming on islet development. Islet counts and size were quantified and correlated with data from intravenous glucose tolerance tests (ivGTT) obtained from dams and their offspring. Average islet size was decreased in PA female infants along with corresponding increases in islet number, while islet fractional area was preserved. Infants also demonstrated an increase in both the proliferation marker Ki67 within islets and the beta to alpha cell ratio suggestive of enhanced beta cell expansion. PA adult females have reduced proportion of small islets without changes in proliferative or apoptotic markers, or in beta to alpha cell ratios. Together, these data suggest in utero androgen excess combined with mild maternal glucose intolerance alter infant and adult islet morphology, implicating deviant islet development. Marked infant, but subtle adult, morphological differences provide evidence of islet post-natal plasticity in adapting to changing physiologic demands: from insulin sensitivity and relative hypersecretion to insulin resistance and diminished insulin response to glucose in the mature PCOS-like phenotype

    The Digital Transformation of the News Media Business – Paid Content and Entrepreneurship in Digital Journalism

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    The digital transformation of the news business continues to agitate publishers. Concerned about declining sales in the print segment, legacy outlets, local news companies and freelance journalists alike search for ways to monetize digital journalism properly. At first glance, digital journalism and its monetisation as paid content seem a promising effort. The digitisation of the news business enabled distribution at a marginal cost of almost zero while giving journalists access to new research technologies and lowering the cost of entry for smaller companies. However, while digital journalism enjoys broad popularity and use, online news are gaining few paying customers. Furthermore, online news compete within a larger digital media complex, comprising movies, games, and social media. After 25 years of experimentation, the digital future of journalism is still heavily debated in media management. Concerning the reconstitution as a digital medium, this research examines conditions of success and obstacles for the digital news media business to be successful as a business venture. Therefore, the research question reads What factors enable the viability and entrepreneurial success of the news media business in light of the consequences of digital transformation? The overarching research question is considered from two angles: The first angle concerns the demand side by looking at the antecedents of the audience's willingness to pay for paid content. The second angle focuses on the supply side and therefore examines antecedents of success in the context of digital journalistic start-ups and founders. In four studies, this thesis develops an analysis of the online news business with a local focus on the German news market. For this purpose, a variety of methods ranging from qualitative work and literature review to empirical research employing path analysis and predictive analytics are applied. Theoretically, digital transformation, free mentality and other peculiarities of information goods inform the frame of this work. Thus, this research aims at contributing to a financially sustainable news media business

    The Disunity of Consciousness

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    It is commonplace for both philosophers and cognitive scientists to express their allegiance to the "unity of consciousness". This is the claim that a subjectÂ’s phenomenal consciousness, at any one moment in time, is a single thing. This view has had a major influence on computational theories of consciousness. In particular, what we call single-track theories dominate the literature, theories which contend that our conscious experience is the result of a single consciousness-making process or mechanism in the brain. We argue that the orthodox view is quite wrong: phenomenal experience is not a unity, in the sense of being a single thing at each instant. It is a multiplicity, an aggregate of phenomenal elements, each of which is the product of a distinct consciousness-making mechanism in the brain. Consequently, cognitive science is in need of a multi-track theory of consciousness; a computational model that acknowledges both the manifold nature of experience, and its distributed neural basis

    Management of bovine tuberculosis in Michigan wildlife: Current status and near term prospects

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    Surveillance and control activities for bovine tuberculosis (bTB) in free-ranging Michigan white-tailed deer (Odocoileus virginianus) have now been underway for over a decade. Significant progress has been made, lowering apparent prevalence in deer in the core area by >60%, primarily via reduction of deer densities through hunting, and restrictions on public feeding and baiting of deer. These broad strategies of the Michigan Department of Natural Resources (MDNR), implemented with the cooperation of Michigan deer hunters, halved the deer population in the bTB endemic area. However, as hunters see fewer deer, their willingness to sustain aggressive harvests has waned, and public resentment of control measures has grown. During the past four years, apparent prevalence in core area deer has held approximately steady just below 2%. After bottoming out in 2004 at an estimated 10–12 deer/km2, deer numbers have since rebounded by ∼30%. Public compliance with baiting and feeding restrictions has been variable. In general, hunters in the core area do not perceive bTB as a problem, in spite of 13 years of MDNR outreach. To date, MDNR has expended more than US23milliononTB−relatedactivities.Oflate,asubstantialportionofthatfundinghasbeendivertedtosupportotherprogramswhichhavesufferedfrombudgetshortfalls.Livestockherdbreakdownscontinuetooccursporadically,averaging3–4peryear2005topresent.Intotal,46cattleand4captivedeerherdshavebeendiagnosedbTBpositivestatewide,themajorityyieldingonly1positiveanimal.Fivecattleherdsweretwiceinfected,onethrice.MichiganDepartmentofAgriculture(MDA)policyemphasishasshiftedtowardsobtainingproducersupportforwildliferiskmitigationandfarmbiosecurity.Fundinghasprovenalimitingfactor,withthemajorityoftheUS23 million on TB-related activities. Of late, a substantial portion of that funding has been diverted to support other programs which have suffered from budget shortfalls. Livestock herd breakdowns continue to occur sporadically, averaging 3–4 per year 2005 to present. In total, 46 cattle and 4 captive deer herds have been diagnosed bTB positive statewide, the majority yielding only 1 positive animal. Five cattle herds were twice infected, one thrice. Michigan Department of Agriculture (MDA) policy emphasis has shifted towards obtaining producer support for wildlife risk mitigation and farm biosecurity. Funding has proven a limiting factor, with the majority of the US63 million spent to date devoted to whole herd testing. Nevertheless, some initiatives justify cautious optimism. Promising research to support eventual vaccination of wild deer continues. Some hunters and landowners have begun to recognize the costs of high deer densities and supplemental feeding. A peninsula-wide ban on baiting and feeding was enacted. Some cattle producers, recognizing their precarious circumstances, have begun work to change long-held prevailing opinions among their peers about farm biosecurity. Yet formidable challenges remain, and evidence suggests that eradication of bTB, if it can be achieved, will take decades, and will require greater public and political resolve than has been demonstrated thus far

    Versatility from a Single Song: The Case of the Nightingale Wren

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    Secondary messenger signalling influences Pseudomonas aeruginosa adaptation to sinus and lung environments

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    Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis, and chronic obstructive pulmonary disease. Prolonged infection allows the accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonizing upper airway environments. Here, we model this process using an experimental evolution approach. Pseudomonas aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments-sinus and lungs, under CF and non-CF conditions-selected for loss of twitching motility, increased resistance to multiple antibiotic classes, and a hyper-biofilm phenotype. These traits conferred increased airway colonization potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching, and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included the loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.</p

    In-Vivo Estimates of Axonal Characteristics Using Optimized Diffusion MRI Protocols for Single Fibre Orientation

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    This work presents diffusion MR protocols that allow estimation of axonal parameters like diameter and density in the live human brain. Previous approaches demand very high field experimental systems or suffer from long acquisition times and are therefore impractical for use in clinical studies. We propose a method that significantly reduces scan time by making use of the a-priori known fibre orientation in structures with well defined single fibre (SF) organisation like the corpus callosum (CC) and produces protocols that can be performed in under 25 minutes on a standard clinical system. Results from a computer simulation experiment show that our SF protocols can generate parameter estimates with similar precision to previously proposed orientation invariant (OI) protocols. Furthermore, we acquire the 20 minute long SF protocol and the 1 hour long OI protocol in a scan/rescan study on two healthy subjects and compare the axonal parameter maps from both protocols. © 2010 Springer-Verlag

    Twenty-four-hour ambulatory blood pressure monitoring efficacy of perindopril/indapamide first-line combination in hypertensive patients: the REASON study

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    Background: Circadian blood pressure (BP) measurements provide more information on hypertensive complications than office BP measurements. The purpose of this study was to analyze the efficacy of the first-line combination of perindopril 2 mg plus indapamide 0.625 mg versus atenolol 50 mg on BP parameters and variability over 24 h in patients with hypertension. Methods: A double-blind, randomized, controlled, 12-month study comparing perindopril/indapamide and atenolol was performed in 201 patients (age 55.0 years) with uncomplicated sustained essential hypertension. Ambulatory BP measurements (ABPM) were done every 15 min over 24 h. Results: After 1 year of treatment, the decrease in systolic BP was significantly greater for perindopril/indapamide than for atenolol during the entire 24-h period (-13.8 ν −9.2 mm Hg), the daytime and the nighttime periods (P < .01). Diastolic blood pressure (DBP) variations were comparable for the two groups (−7.2 ν −8.3 mm Hg, NS). Pulse pressure (PP) reduction was also significantly greater for perindopril/indapamide than for atenolol (for the whole 24 h, −6.6 ν −0.9 mm Hg, P < .001). The through to peak (T/P) BP ratio and the smoothness index were comparable in the two groups for DBP. For systolic blood pressure (SBP), higher values of the T/P ratio (0.80 ν 0.59) and the smoothness index (1.45 ν 0.98; P < .02) were achieved for the perindopril/indapamide combination than for atenolol. Conclusions: The perindopril/indapamide first-line combination decreased SBP and PP more effectively than atenolol. Moreover, the BP control effect was smooth and consistent throughout the 24-h dosing interval and BP reduction variability was lower than the one induced by atenolo

    Bidirectional magnetic nanowire shift register

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    We experimentally demonstrate a shift register based on an open-ended chain of ferromagnetic NOT gates which can support bidirectional data flow. Up to eight data bits are electrically input to the device, stored for extended periods without power, and then output either in a first in first out or last in first out scheme. Comparing to traditional transistor-based logic, this bidirectionality offers a range of devices that are reversible and not limited to only one mode of operation
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