664 research outputs found

    Point discharge pulse measurements in atmospheric electricity

    Get PDF
    Previous methods for estimating the charge transferred to earth by point discharge are reviewed. It is concluded that point discharge on trees may well make a large contribution to this transfer of charge but that no reliable method of measurement has previously been duvised. A laboratory study of the pulsed nature of the point discharge currents produced at metal points and natural points has been made. It is concluded from these measurements that the amplitude and repetition frequency of these current pulses can be used to give the total discharge current. A new method for measuring point discharge currents in trees has now been developed and the apparatus successfully calibrated. This takes the form of a capacitative electrode, attached to a branch at the top of a tree, which detects pulses of point discharge current in the tree. The electrode is connected to an electronic pulse detector which gives a measure of the point discharge current in the tree. Measurements of point discharge currents have been made in two trees over a period of three months in a plantation of conifers in Weardale. The potential gradient and the point discharge current through a metal point were measured outside the plantation over a period of eleven months. The charge transferred to earth by point discharge on one tree in three months was found to be 4.3 x 10(^-4)C whereas for the metal point in the same period the charge transferred was 72 x 10(^-4)C. It is concluded that this difference is a result of the higher potential gradients necessary to initiate point discharge on the tree compared with those for the metal point. The point discharge measurements for two trees, one on the edge and one inside the plantation, are compared and found to be of similar magnitudes. The charge per unit area transferred to earth by point discharge on all the trees in the plantation is estimated to be 270 C km(^-2) yr(^-1)

    Anwenderperspektive auf FEM-Software

    Get PDF
    Der vorliegende Artikel befasst sich mit der Nutzerperspektive auf FEM- (Finite Elemente Methode) Software. Es wird eine Umfrage unter Anwendern durchgeführt und ausgewertet, die die aktuelle Nutzung sowie Benutzerwünsche nach Weiterentwicklung des Forschungsfeldes untersucht.This article deals with the user’s perspective on FEM (Finite Element Method) software. A user survey is undertaken and evaluated which examines the current use as well as the user’s wishes for further development in the research field

    Critical values for Lawshe's content validity ratio: revisiting the original methods of calculation

    Get PDF
    YesThe content validity ratio originally proposed by Lawshe is widely used to quantify content validity and yet methods used to calculate the original critical values were never reported. Methods for original calculation of critical values are suggested along with tables of exact binomial probabilities

    Increased Birth Weight is Associated with Altered Gene Expression in Neonatal Foreskin

    Get PDF
    Elevated birth weight is linked to glucose intolerance and obesity health-related complications later in life. No studies have examined if infant birth weight is associated with gene expression markers of obesity and inflammation in a tissue that comes directly from the infant following birth. We evaluated the association between birth weight and gene expression on fetal programming of obesity. Foreskin samples were collected following circumcision, and gene expression analyzed comparing the 15% greatest birth weight infants (n = 7) v. the remainder of the cohort (n = 40). Multivariate linear regression models were fit to relate expression levels on differentially expressed genes to birth weight group with adjustment for variables selected from a list of maternal and infant characteristics. Glucose transporter type 4 (GLUT4), insulin receptor substrate 2 (IRS2), leptin receptor (LEPR), lipoprotein lipase (LPL), low-density lipoprotein receptor-related protein 1 (LRP1), matrix metalloproteinase 2 (MMP2), plasminogen activator inhibitor-1 (PAI-1) and transcription factor 7-like 2 (TCF7L2) were significantly upregulated and histone deacetylase 1 (HDAC1) and thioredoxin (TXN) downregulated in the larger birth weight neonates v. controls. Multivariate modeling revealed that the estimated adjusted birth weight group difference exceeded one standard deviation of the expression level for eight of the 10 genes. Between 25 and 50% of variation in expression level was explained by multivariate modeling for eight of the 10 genes. Gene expression related to glycemic control, appetite/energy balance, obesity and inflammation were altered in tissue from babies with elevated birth weight, and these genes may provide important information regarding fetal programming in macrosomic babies

    Characteristics of self-care interventions for patients with a chronic condition: A scoping review

    Get PDF
    Background: Self-care is a fundamental element of treatment for patients with a chronic condition and a major focus of many interventions. A large body of research exists describing different types of self-care interventions, but these studies have never been compared across conditions. Examination of heterogeneous interventions could provide insights into effective approaches that should be used in diverse patient populations. Objectives: To provide a comprehensive and standardized cross-condition overview of interventions to enhance self-care in patients with a chronic condition. Specific aims were to: 1) identify what self-care concepts and behaviors are evaluated in self-care interventions; 2) classify and quantify heterogeneity in mode and type of delivery; 3) quantify the behavior change techniques used to enhance self-care behavior; and 4) assess the dose of self-care interventions delivered. Design: Scoping review DATA SOURCES: Four electronic databases - PubMed, EMBASE, PsychINFO and CINAHL - were searched from January 2008 through January 2019. Eligibility criteria for study selection: Randomized controlled trials (RCTs) with concealed allocation to the intervention were included if they compared a behavioral or educational self- care intervention to usual care or another self-care intervention and were conducted in adults. Nine common chronic conditions were included: hypertension, coronary artery disease, arthritis, chronic kidney disease, heart failure, stroke, asthma, chronic obstructive lung disease, and type 2 diabetes mellitus. Diagnoses that are psychiatric (e.g. schizophrenia), acute rather than chronic, or benefitting little from self-care (e.g. dementia) were excluded. Studies had to be reported in English with full-text available. Results: 9309 citations were considered and 233 studies were included in the final review. Most studies addressed type 2 diabetes mellitus (n = 85; 36%), hypertension (n = 32; 14%) or heart failure (n = 27; 12%). The majority (97%) focused on healthy behaviors like physical activity (70%), dietary intake (59%), and medication management (52%). Major deficits found in self-care interventions included a lack of attention to the psychological consequences of chronic illness, technology and behavior change techniques were rarely used, few studies focused on helping patients manage signs and symptoms, and the interventions were rarely innovative. Research reporting was generally poor. Conclusions: Major gaps in targeted areas of self-care were identified. Opportunities exist to improve the quality and reporting of future self-care intervention research. Registration: The study was registered in the PROSPERO database (#123,719)

    Realistic Operational Modeling for a Spin Stabilized CubeSat: Challenges and Anticipated Control Performance

    Get PDF
    Recently, ASTRA LLC. has teamed with the Space Dynamics Laboratory of Utah State University to design a 1.5U CubeSat system for measuring electric fields. Such a system requires 2-axis control and relatively high spin-rates. The spacecraft is called the Double-probe Instrumentation for Measuring Electric-fields (DIME) SensorSat and is funded by the Air Force Research Laboratory SBIR program. In order to design and test control algorithms and verify requirements, ASTRA has developed a modeling-tool for a CubeSat 2-axis control system. First, a brief overview of the DIME SensorSat and attitude system is provided and the DIME attitude requirements are introduced. Next the operational attitude model is discussed followed by simulation results for the various operational phases of a spin-stabilized CubeSat. Finally, we present some anticipated challenges and related simulations for a spin-stabilized CubeSat

    Complex-type N-glycan recognition by potent broadly neutralizing HIV antibodies

    Get PDF
    Broadly neutralizing HIV antibodies (bNAbs) can recognize carbohydrate-dependent epitopes on gp120. In contrast to previously characterized glycan-dependent bNAbs that recognize high-mannose N-glycans, PGT121 binds complex-type N-glycans in glycan microarrays. We isolated the B-cell clone encoding PGT121, which segregates into PGT121-like and 10-1074–like groups distinguished by sequence, binding affinity, carbohydrate recognition, and neutralizing activity. Group 10-1074 exhibits remarkable potency and breadth but no detectable binding to protein-free glycans. Crystal structures of unliganded PGT121, 10-1074, and their likely germ-line precursor reveal that differential carbohydrate recognition maps to a cleft between complementarity determining region (CDR)H2 and CDRH3. This cleft was occupied by a complex-type N-glycan in a “liganded” PGT121 structure. Swapping glycan contact residues between PGT121 and 10-1074 confirmed their importance for neutralization. Although PGT121 binds complex-type N-glycans, PGT121 recognized high-mannose-only HIV envelopes in isolation and on virions. As HIV envelopes exhibit varying proportions of high-mannose- and complex-type N-glycans, these results suggest promiscuous carbohydrate interactions, an advantageous adaptation ensuring neutralization of all viruses within a given strain

    Evaluating complementary and alternative medicine interventions: in search of appropriate patient-centered outcome measures

    Get PDF
    BACKGROUND: Central to the development of a sound evidence base for Complementary and Alternative Medicine (CAM) interventions is the need for valid, reliable and relevant outcome measures to assess whether the interventions work. We assessed the specific needs for a database that would cover a wide range of outcomes measures for CAM research and considered a framework for such a database. METHODS: The study was a survey of CAM researchers, practitioners and students. An online questionnaire was emailed to the members of the Canadian Interdisciplinary Network for CAM Research (IN-CAM) and the CAM Education and Research Network of Alberta (CAMera). The majority of survey questions were open-ended and asked about outcome measures currently used, outcome measures' assessment criteria, sources of information, perceived barriers to finding outcome measures and outcome domains of importance. Descriptive quantitative analysis and qualitative content analysis were used. RESULTS: One hundred and sixty-four completed surveys were received. Of these, 62 respondents reported using outcome measures in their CAM research and identified 92 different specific outcomes. The most important barriers were the fact that, for many health concepts, outcome measures do not yet exist, as well as issues related to accessibility of instruments. Important outcome domains identified included physical, psychological, social, spiritual, quality of life and holistic measures. Participants also mentioned the importance of individualized measures that assess unique patient-centered outcomes for each research participant, and measures to assess the context of healing and the process of healing. CONCLUSION: We have developed a preliminary framework that includes all components of health-related outcomes. The framework provides a foundation for a larger, comprehensive collection of CAM outcomes. It fits very well in a whole systems perspective, which requires an expanded set of outcome measures, such as individualized and holistic measures, with attention to issues of process and context
    • …
    corecore