1,407 research outputs found

    Knowledge Sharing, Maintenance, and Use in Online Support Communities.

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    Widespread adoption of information technologies has fostered new social arrangements and opportunities for large-scale collaboration. Many of these new collaborations occur in online support communities where members help each other make sense of, and deal with, a particular topic (e.g., website design, cancer treatment). Many of these communities struggle with meeting the divergent needs of novices, experts, and those who overhear their conversations. A few communities have recently augmented their existing threaded conversations (e.g., email list discussions) with a wiki repository which serves a similar purpose as an FAQ document. I demonstrate how a threaded conversation and wiki repository can complement each other by describing in detail a technical support community (css-d) where they do. Using a mixed method approach I empirically examine how activity is organized to leverage both resources through an analysis of the governance structure, social roles and norms, information genres, participation patterns, and technical features. I also use an action research methodology to help 3 online medical support communities implement a wiki repository. I first the limitations of using a community conversation for reuse by arguing that the very same characteristics that make community conversations useful to their participants (e.g., their personalized, immediate, and social nature) make their reuse by onlookers problematic. I then describe how a wiki repository was used by the css-d community to create reusable content that complements the discussion. I characterize the wiki genres most useful to the community (e.g., Annotated Links, Debate summaries, How To pages, Articles) and describe the processes important to their creation, and how they lead to content that fills information gaps, is reusable, and relevant to the masses. I describe how the synergistic relationship between community conversation and wiki repositories helps overcome some of the information sharing and maintenance challenges common to help-based communities, as well as how it helps overcome some of the common social maintenance challenges of online communities such as keeping the discussion on topic and avoiding contentious debates. Finally, I characterize some of the challenges of implementing wiki repositories and collaborative authoring, such as the hesitancy of members to edit others’ work.Ph.D.InformationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/57608/2/shakmatt_1.pd

    Chicory roots improves the taste and odour of organic pork

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    The carbohydrate inulin is known to reduce the production of skatole in pigs. This is caused by inulin changing the intestinal flora, so that the bacteria that produce skatole are held in check. This change in intestinal flora also reduces the number of intestinal parasites in the pigs. However the high cost of inulin makes its use in pig feed impractical. Chicory root contains inulin and a series of other carbohydrates and secondary metabolites. Therefore we have examined whether chicory root can replace pure inulin and thereby reduce boar taint, improve the taste of pork and reduce the infection of pigs with pathogenic parasites and bacteria

    Tumor Necrosis Factor Polymorphism Affects Transplantation Outcome in Patients with Myelodysplastic Syndrome but Not in Those with Chronic Myelogenous Leukemia, Independent of the Presence of HLA-DR15

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    Both the presence of HLA-DR15 and tumor necrosis factor (TNF)-α levels have been reported to affect outcome after hematopoietic cell transplantation (HCT). Patients with a myelodysplastic syndrome (MDS) show a high prevalence of HLA-DR15 and express high levels of TNF-α in the bone marrow. The present analysis involving 7950 patients showed an HLA-DR15 frequency of 31% in patients with MDS, compared with only 23% in patients with chronic myelogenous leukemia (CML). HLA-DR15 was more prevalent in Caucasian patients than in non-Caucasian patients (P = .01). The numbers of patients in the non-Caucasian subgroups were too small to allow further analysis. Among Caucasian patients with MDS and CML, the presence of HLA-DR15 did not significantly affect the occurrence of graft-versus-host disease, relapse, nonrelapse mortality (NRM), or survival. However, there was a significant correlation between DR15 and TNF polymorphisms at position -308 among patients with MDS, and the TNF-308 AG genotype conferred an increased risk of NRM compared with the GG genotype (hazard ratio [HR], 1.49; P = .02), even after adjusting for DR15. Conversely, the TNF-863 AA genotype was correlated with decreased overall mortality and NRM compared with the CC genotype (HR, 0.36, P = .04 vs HR, 0.13, P = .04), even after adjusting for DR15. There was no significant association between TNF-308 or -863 polymorphisms and transplantation outcome in CML patients. These results suggest that TNF polymorphisms, but not DR15, affect transplantation outcome in a disease-dependent manner

    Cikorierødder forbedrer smag og lugt i økologisk svinekød

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    Sukkerstoffet inulin er kendt for at kunne nedsætte dannelsen af skatol hos svin. Det skyldes at inulin ændrer tarmfloraen, så bakterier der danner skatol bliver holdt i skak. Samtidig bevirker den ændrede tarmflora at grisene får færre indvoldsorm. Inulin er imidlertid for dyrt til, at det kan betale sig at bruge det i svinefoder. Cikorierødder indeholder inulin og en række andre kulhydrater plus sekundære metabolitter. Derfor har vi undersøgt om cikorierødder kan erstatte ren inulin og derigennem mindske ornelugten, forbedre smagen og nedsætte grisenes smitte med sygdomsfremkaldende parasitter og bakterier

    Protein Replacement Therapy Partially Corrects the Cholesterol-Storage Phenotype in a Mouse Model of Niemann-Pick Type C2 Disease

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    Niemann-Pick type C2 (NPC2) disease is a fatal autosomal recessive neurovisceral degenerative disorder characterized by late endosomal-lysosomal sequestration of low-density lipoprotein derived cholesterol. The breach in intracellular cholesterol homeostasis is caused by deficiency of functional NPC2, a soluble sterol binding protein targeted to the lysosomes by binding the mannose-6-phosphate receptor. As currently there is no effective treatment for the disorder, we have investigated the efficacy of NPC2 replacement therapy in a murine gene-trap model of NPC2-disease generated on the 129P2/OlaHsd genetic background. NPC2 was purified from bovine milk and its functional competence assured in NPC2-deficient fibroblasts using the specific cholesterol fluorescent probe filipin. For evaluation of phenotype correction in vivo, three-week-old NPC2−/− mice received two weekly intravenous injections of 5 mg/kg NPC2 until trial termination 66 days later. Whereas the saline treated NPC2−/− mice exhibited massive visceral cholesterol storage as compared to their wild-type littermates, administration of NPC2 caused a marked reduction in cholesterol build up. The histological findings, indicating an amelioration of the disease pathology in liver, spleen, and lungs, corroborated the biochemical results. Little or no difference in the overall cholesterol levels was observed in the kidneys, blood, cerebral cortex and hippocampus when comparing NPC2−/− and wild type mice. However, cerebellum cholesterol was increased about two fold in NPC2−/− mice compared with wild-type littermates. Weight gain performance was slightly improved as a result of the NPC2 treatment but significant motor coordination deficits were still observed. Accordingly, ultrastructural cerebellar abnormalities were detected in both saline treated and NPC2 treated NPC2−/− animals 87 days post partum. Our data indicate that protein replacement may be a beneficial therapeutic approach in the treatment of the visceral manifestations in NPC2 disease and further suggest that neurodegeneration is not secondary to visceral dysfunction

    A Spitzer Transmission Spectrum for the Exoplanet GJ 436b, Evidence for Stellar Variability, and Constraints on Dayside Flux Variations

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    In this paper we describe a uniform analysis of eight transits and eleven secondary eclipses of the extrasolar planet GJ 436b obtained in the 3.6, 4.5, and 8.0 micron bands using the IRAC instrument on the Spitzer Space Telescope between UT 2007 June 29 and UT 2009 Feb 4. We find that the best-fit transit depths for visits in the same bandpass can vary by as much as 8% of the total (4.7 sigma significance) from one epoch to the next. Although we cannot entirely rule out residual detector effects or a time-varying, high-altitude cloud layer in the planet's atmosphere as the cause of these variations, we consider the occultation of active regions on the star in a subset of the transit observations to be the most likely explanation. We reconcile the presence of magnetically active regions with the lack of significant visible or infrared flux variations from the star by proposing that the star's spin axis is tilted with respect to our line of sight, and that the planet's orbit is therefore likely to be misaligned. These observations serve to illustrate the challenges associated with transmission spectroscopy of planets orbiting late-type stars; we expect that other systems, such as GJ 1214, may display comparably variable transit depths. Our measured 8 micron secondary eclipse depths are consistent with a constant value, and we place a 1 sigma upper limit of 17% on changes in the planet's dayside flux in this band. Averaging over the eleven visits gives us an improved estimate of 0.0452% +/- 0.0027% for the secondary eclipse depth. We combine timing information from our observations with previously published data to produce a refined orbital ephemeris, and determine that the best-fit transit and eclipse times are consistent with a constant orbital period. [ABRIDGED]Comment: 26 pages, 18 figures, 7 tables in emulateapj format. Accepted for publication in Ap

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Faecal calprotectin: factors affecting levels and its potential role as a surrogate marker for risk of development of Crohn's Disease.

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    BACKGROUND: Faecal calprotectin (FC) is one of the most widely used non-invasive tests for the diagnosis and assessment of Crohn's disease (CD) activity. Despite this, factors other than disease activity which affect levels have not been extensively reviewed. This is of importance when using FC in the diagnostic setting but also may be of utility in studying the aetiology of disease. OBJECTIVES: Our review outlines environmental risk factors that affect FC levels influencing diagnostic accuracy and how these may be associated with risk of developing CD. FC as a surrogate marker could be used to validate risk factors established in case control studies where prospective studies are not feasible. Proof of this concept is provided by our identification of obesity as being associated with elevated FC, our subsequent confirmation of obesity as risk factor for CD and the subsequent verification in prospective studies, as well as associations of lack of physical activity and dietary fibre intake with elevated FC levels and their subsequent confirmation as risk factors in prospective studies. CONCLUSION: We believe that FC is likely to prove a useful surrogate marker for risk of developing CD. This review has given a theoretical basis for considering the epidemiological determinants of CD which to date has been missing
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