308 research outputs found

    Characteristics and Risk of Microgrid Outages from a Complex Systems Point of View

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    Cordova is a town of approximately 2,000 people located on the southern coast of Alaska. A power grid for a town this size, with a large seasonal fishing economy, is considered a moderate to large sized microgrid in terms of power produced. Understanding the vulnerabilities and risks of failures in such a grid is important for planning and operations. Investigating these characteristics in the context of complex system dynamics is a novel approach. The analysis of Cordova’s microgrid is a case study relevant to a large class of microgrid communities. We analyze the outage data based on size, cause characteristics and load demand on the system and find long time correlations and power laws in the failure size distributions. Finally we apply a risk metric to give a single numerical value to the risk of an outage occurring during certain time periods and under certain conditions

    What are the beliefs of pediatricians and dietitians regarding complementary food introduction to prevent allergy?

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    <p>Abstract</p> <p>Background</p> <p>The timing of complementary food introduction is controversial. Providing information on the timing of dietary introduction is crucial to the primary prevention of food allergy. The American Academy of Pediatrics offers dietary recommendations that were updated in 2008.</p> <p>Objective</p> <p>Identify the recommendations that general pediatricians and registered dietitians provide to parents and delineate any differences in counselling.</p> <p>Methods</p> <p>A 9-item survey was distributed to pediatricians and dietitians online and by mail. Information on practitioner type, gender, length of practice and specific recommendations regarding complementary food introduction and exposure was collected.</p> <p>Results</p> <p>181 surveys were returned with a 54% response rate from pediatricians. It was not possible to calculate a meaningful dietitian response rate due to overlapping email databases. 52.5% of all respondents were pediatricians and 45.9% were dietitians. The majority of pediatricians and dietitians advise mothers that peanut abstinence during pregnancy and lactation is unnecessary. Dietitians were more likely to counsel mothers to breastfeed their infants to prevent development of atopic dermatitis than pediatricians. Hydrolyzed formulas for infants at risk of developing allergy were the top choice of formula amongst both practitioners. For food allergy prevention, pediatricians were more likely to recommend delayed introduction of peanut and egg, while most dietitians recommended no delay in allergenic food introduction.</p> <p>Conclusions</p> <p>In the prophylaxis of food allergy, pediatricians are less aware than dietitians of the current recommendation that there is no benefit in delaying allergenic food introduction beyond 4 to 6 months. More dietitians than pediatricians believe that breastfeeding decreases the risk of atopic dermatitis. Practitioners may benefit from increased awareness of current guidelines.</p

    Motivations Behind Sustainable Purchasing

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    Sustainability issues in purchasing are receiving greater attention. Literature is rapidly growing, with several research programs being initiated to investigate the topic. This study presents the results of a research project which aims to reveal and structure the motivating forces leading companies to make efforts in sustainability purchasing and the means used to attain achievements in some fields of sustainability. Results presented in the literature are scattered in terms of the fields of sustainability: most of the studies focus only on green or corporate social responsibility issues and there is a lack of exploratory models. Sustainability in purchasing is addressed in a comprehensive way including green, social responsibility and corporate growth issues. After presenting the results of a literature review, theoretical development was undertaken to create a framework in which it is possible to describe the means of sustainability applied and the motivating forces behind them. This framework serves as the basis for an empirical investigation among Hungarian companies. Empirical results confirm the usefulness of the theoretical framework: the number and the characteristics of sustainability activities were determined by the particular types of motivation – to avoid negative effects, to achieve compliance with expectations and to attain positive effects

    Suicidal thoughts and depressive feelings amongst Estonian schoolchildren: effect of family relationship and family structure

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    Depressive feelings and suicidal ideation in a non-clinical sample of adolescents in Estonia were analysed in the context of family structure, mutual relationships amongst family members and schoolchildren's preferences regarding intimate personal contacts with particular family members. Data from the WHO collaborative study 'Health Behaviour in School-aged Children 2005/2006' (HBSC) were used. A representative sample of schoolchildren aged 11, 13 and 15 years completed the semi-structured questionnaire. The analyses included only adolescents living in households with at least one birth parent. The subjects were 4,389 schoolchildren (2,178 boys and 2,211 girls), who were divided into three groups based on: (1) suicidal thoughts, with or without depressive feelings; (2) depressive feelings; and (3) neither suicidal thoughts nor depressive feelings. Multinomial logistic regression was used. The proportion of depressive feelings increased with age for both boys and girls. Girls expressed depressive feelings more frequently than boys from ages 13 and 15 years, and suicidal thoughts from age 15 years. Self-reported satisfaction with relationships in the family reduced the likelihood of depressive feelings and suicidal thoughts. Good communication with the parents reduced the likelihood of suicidal thoughts in all age groups. Adolescents who were satisfied with their family relationships suffered less frequently from depressive feelings and suicidal thoughts. The best environment for an adolescent was a family with both birth parents. Of the adolescents in 'non-intact' families, those with a step-parent in the family showed suicidal thoughts more frequently than those in single-parent families. Associations between family-related variables and suicidal thoughts were significant even after adjusting for family economic deprivation score

    National clinical practice guidelines for food allergy and anaphylaxis:an international assessment

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    Background: clinical practice guidelines are important tools to promote evidence-based clinical care, but not all countries have the capacity or infrastructure to develop these in-house. The European Academy of Allergy and Clinical Immunology has recently developed guidelines for the prevention, diagnosis and management of food allergy and the management of anaphylaxis. In order to inform dissemination, adaptation and implementation plans, we sought to identify countries that have/do not have national guidelines for food allergy and anaphylaxis.Methods: two reviewers independently searched PubMed to identify countries with guidelines for food allergy and/or anaphylaxis from the inception of this database to December 2016. This was supplemented with a search of the Agency for Healthcare Research and Quality's National Guideline Clearinghouse in order to identify any additional guidelines that may not have been reported in the peer-reviewed literature. Data were descriptively and narratively synthesized.Results: overall, 5/193 (3%) of countries had at least one guideline for food allergy or anaphylaxis. We found that one (1%) country had a national guideline for the prevention of food allergy, three (2%) countries had a guideline for the diagnosis of food allergy and three (2%) countries had a guideline for the management of food allergy. Three (2%) countries had an anaphylaxis guideline.Conclusions: this study concludes that the overwhelming majority of countries do not have any national clinical practice guidelines for food allergy or anaphylaxis

    Lipopolysaccharide O1 Antigen Contributes to the Virulence in Klebsiella pneumoniae Causing Pyogenic Liver Abscess

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    Klebsiella pneumoniae is the common cause of a global emerging infectious disease, community-acquired pyogenic liver abscess (PLA). Capsular polysaccharide (CPS) and lipopolysaccharide (LPS) are critical for this microorganism's ability to spread through the blood and to cause sepsis. While CPS type K1 is an important virulence factor in K. pneumoniae causing PLA, the role of LPS in PLA is not clear. Here, we characterize the role of LPS O antigen in the pathogenesis of K. pneumoniae causing PLA. NTUH-K2044 is a LPS O1 clinical strain; the presence of the O antigen was shown via the presence of 1,3-galactan in the LPS, and of sequences that align with the wb gene cluster, known to produce O-antigen. Serologic analysis of K. pneumoniae clinical isolates demonstrated that the O1 serotype was more prevalent in PLA strains than that in non-tissue-invasive strains (38/42 vs. 9/32, P<0.0001). O1 serotype isolates had a higher frequency of serum resistance, and mutation of the O1 antigen changed serum resistance in K. pneumoniae. A PLA-causing strain of CPS capsular type K2 and LPS serotype O1 (i.e., O1:K2 PLA strain) deleted for the O1 synthesizing genes was profoundly attenuated in virulence, as demonstrated in separate mouse models of septicemia and liver abscess. Immunization of mice with the K2044 magA-mutant (K1− O1) against LPS O1 provided protection against infection with an O1:K2 PLA strain, but not against infection with an O1:K1 PLA strain. Our findings indicate that the O1 antigen of PLA-associated K. pneumoniae contributes to virulence by conveying resistance to serum killing, promoting bacterial dissemination to and colonization of internal organs after the onset of bacteremia, and could be a useful vaccine candidate against infection by an O1:K2 PLA strain
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