829 research outputs found
Clastic Sediments in the Butler Cave – Sinking Creek System, Virginia, USA
The Butler Cave - Sinking Creek System in Bath County, Virginia, consists of a master trunk passage along the axis of a syncline with a trellis arrangement of dip-oriented side caves. The western set of dip passages contain a sequence of massively and chaotically bedded sand and cobble sediments. Massive cobble fills also occur in the strike-oriented trunk passage. Cave passages on the eastern side of the syncline contain mostly sand and silt. The light fraction of the sediments consists predominantly of quartz and rock fragments. The sediments contain several percent heavy minerals composed of iron oxides, zircon, rutile, tourmaline and other minerals. Measurement of the visible and near infrared diffuse reflectance spectra shows at least three populations of sediments to be present: an iron-rich, clay-poor group; a clay-rich group; and a gypsiferous sediment. The iron minerals provided a paleomagnetic signal. Sediments from the trunk passage, deposited by recent underground drainage, contained a normal pole direction. Sediments from the dip passages were paleomagnetically reversed, showing the deposition dates from prior to 780,000 years. In one instance reversed polarity deposits overlie normal polarity, implying a minimum age of 990,000 years for the reversed sediments. Â Â
α<sub>1L</sub>-adrenoceptors mediate contraction of human erectile tissue
α1-adrenoceptor antagonists can impact upon sexual function and have potential in the treatment of erectile dysfunction. Human erectile tissue contains predominantly α1A-adrenoceptors, and here we examined whether contractions of this tissue are mediated by the functional phenotype, the α1L-adrenoceptor. Functional experiments using subtype selective agonists and antagonists, along with radioligand ([3H]tamsulosin) binding assays, were used to determine the α1-adrenoceptor population. A61603, a α1A-adrenoceptor agonist, was a full agonist with a potency 21-fold greater than that of noradrenaline. The α1A- and α1D-adrenoceptor antagonist tamsulosin antagonized noradrenaline responses with high affinity (pKD = 9.7 ± 0.3), whilst BMY7378 (100 nM) (α1D-adrenoceptor antagonist) failed to antagonize responses. In contrast, relatively low affinity estimates were obtained for both prazosin (pKD = 8.2 ± 0.1) and RS17053 (pKD = 6.9 ± 0.2), antagonists which discriminate between the α1A- and α1L-adrenoceptors. [3H]Tamsulosin bound with high affinity to the receptors of human erectile tissue (pKD = 10.3 ± 0.1) with a receptor density of 28.1 ± 1.4 fmol mg−1 protein. Prazosin displacement of [3H]tamsulosin binding revealed a single homogenous population of binding sites with a relatively low affinity for prazosin (pKi = 8.9). Taken together these data confirm that the receptor mediating contraction in human erectile tissue has the pharmacological properties of the α1L-adrenoceptor. Keywords: Erectile tissue, α1-adrenoceptor subtypes, α1L-adrenoceptor, Tamsulosin, Prazosi
Farm Production Analysis Training for Small Farmers
A partnership between Penn State Cooperative Extension and the Farm Service Agency has developed a successful production training program for more than 367 farmers. Farmers received training in producing planning and budgets, partial budgeting, and livestock and agronomic basics. Significant gains in knowledge occurred in multi-year planning, enterprise budgeting, and use of the Penn State Agronomy Guide. Designing workshop material for low-producing farmers proved difficult because most participants, while finding the topics helpful, also found the material too advanced. Future focus will encourage greater involvement with private-sector institutions and coordination between production and management Extension specialists
Comparative metal oxide nanoparticle toxicity using embryonic zebrafish
AbstractEngineered metal oxide nanoparticles (MO NPs) are finding increasing utility in the medical field as anticancer agents. Before validation of in vivo anticancer efficacy can occur, a better understanding of whole-animal toxicity is required. We compared the toxicity of seven widely used semiconductor MO NPs made from zinc oxide (ZnO), titanium dioxide, cerium dioxide and tin dioxide prepared in pure water and in synthetic seawater using a five-day embryonic zebrafish assay. We hypothesized that the toxicity of these engineered MO NPs would depend on physicochemical properties. Significant agglomeration of MO NPs in aqueous solutions is common making it challenging to associate NP characteristics such as size and charge with toxicity. However, data from our agglomerated MO NPs suggests that the elemental composition and dissolution potential are major drivers of toxicity. Only ZnO caused significant adverse effects of all MO particles tested, and only when prepared in pure water (point estimate median lethal concentration=3.5–9.1mg/L). This toxicity was life stage dependent. The 24h toxicity increased greatly (∼22.7 fold) when zebrafish exposures started at the larval life stage compared to the 24h toxicity following embryonic exposure. Investigation into whether dissolution could account for ZnO toxicity revealed high levels of zinc ion (40–89% of total sample) were generated. Exposure to zinc ion equivalents revealed dissolved Zn2+ may be a major contributor to ZnO toxicity
D’Agents: Security in a Multiple-Language, Mobile-Agent System
Abstract. Mobile-agent systems must address three security issues: protecting an individual machine, protecting a group of machines, and protecting an agent. In this chapter, we discuss these three issues in the context of D’Agents, a mobile-agent system whose agents can be written in Tcl, Java and Scheme. (D’Agents was formerly known as Agent Tcl.) First we discuss mechanisms existing in D’Agents for protecting an individual machine: (1) cryptographic authentication of the agent’s owner, (2) resource managers that make policy decisions based on the owner’s identity, and (3) secure execution environments for each language that enforce the decisions of the resource managers. Then we discuss our planned market-based approach for protecting machine groups. Finally we consider several (partial) solutions for protecting an agent from a malicious machine.
Measuring health-related quality of life in chronic headache:a comparative evaluation of the Chronic Headache Quality of Life Questionnaire and Headache Impact Test (HIT-6)
Objective: To compare the quality and acceptability of a new headache-specific patient-reported measure the Chronic Headache Quality of Life Questionnaire (CHQLQ), with the Headache Impact Test–6 item (HIT-6), in people meeting an epidemiological definition of chronic headaches.Methods: Participants in the feasibility stage of the Chronic Headache Education and Self-management Study (CHESS) (N=130) completed measures three times during a 12-week prospective cohort study. Data quality, measurement acceptability, reliability, validity, responsiveness to change, and score interpretation were determined. Semi-structured cognitive interviews explored measurement relevance, acceptability, clarity, and comprehensiveness.Results: Both measures were well completed with few missing items. The CHQLQ’s inclusion of emotional wellbeing items increased its relevance to participant’s experience of chronic headache. End effects were present at item level only for both measures. Structural assessment supported the three and one-factor solutions of the CHQLQ and HIT-6, respectively. Both the CHQLQ (range 0.87 to 0.94) and HIT-6 (0.90) were internally consistent, with acceptable temporal stability over 2-weeks (CHQLQ range 0.74 to 0.80; HIT-6 0.86). Both measures responded to change in headache-specific health at 12-weeks (CHQLQ smallest detectable change (improvement) range 3 to 5; HIT-6 2.1). Conclusions: While both measures are structurally valid, internally consistent, temporally stable and responsive to change, the CHQLQ has greater relevance to the patient experience of chronic headache. <br/
Measuring health-related quality of life in chronic headache: A comparative evaluation of the Chronic Headache Quality of Life Questionnaire and Headache Impact Test (HIT-6).
OBJECTIVE: To compare the quality and acceptability of a new headache-specific patient-reported measure, the Chronic Headache Quality of Life Questionnaire (CHQLQ) with the six-item Headache Impact Test (HIT-6), in people meeting an epidemiological definition of chronic headaches. METHODS: Participants in the feasibility stage of the Chronic Headache Education and Self-management Study (CHESS) (n = 130) completed measures three times during a 12-week prospective cohort study. Data quality, measurement acceptability, reliability, validity, responsiveness to change, and score interpretation were determined. Semi-structured cognitive interviews explored measurement relevance, acceptability, clarity, and comprehensiveness. RESULTS: Both measures were well completed with few missing items. The CHQLQ's inclusion of emotional wellbeing items increased its relevance to participant's experience of chronic headache. End effects were present at item level only for both measures. Structural assessment supported the three and one-factor solutions of the CHQLQ and HIT-6, respectively. Both the CHQLQ (range 0.87 to 0.94) and HIT-6 (0.90) were internally consistent, with acceptable temporal stability over 2 weeks (CHQLQ range 0.74 to 0.80; HIT-6 0.86). Both measures responded to change in headache-specific health at 12 weeks (CHQLQ smallest detectable change (improvement) range 3 to 5; HIT-6 2.1). CONCLUSIONS: While both measures are structurally valid, internally consistent, temporally stable, and responsive to change, the CHQLQ has greater relevance to the patient experience of chronic headache.Trial registration number: ISRCTN79708100. Registered 16th December 2015, http://www.isrctn.com/ISRCTN79708100
Myths and Facts About Static Application Security Testing Tools: An Action Research at Telenor Digital
It is claimed that integrating agile and security in practice is challenging. There is the notion that security is a heavy process, requires expertise, and consumes developers’ time. These contrast with the agile vision. Regardless of these challenges, it is important for organizations to address security within their agile processes since critical assets must be protected against attacks. One way is to integrate tools that could help to identify security weaknesses during implementation and suggest methods to refactor them. We used quantitative and qualitative approaches to investigate the efficiency of the tools and what they mean to the actual users (i.e. developers) at Telenor Digital. Our findings, although not surprising, show that several barriers exist both in terms of tool’s performance and developers’ perceptions. We suggest practical ways for improvement.publishedVersio
What Developers Want and Need from Program Analysis: An Empirical Study
Program Analysis has been a rich and fruitful field of research for many decades, and countless high quality program analysis tools have been produced by academia. Though there are some well-known examples of tools that have found their way into routine use by practitioners, a common challenge faced by researchers is knowing how to achieve broad and lasting adoption of their tools. In an effort to understand what makes a program analyzer most attractive to developers, we mounted a multi-method investigation at Microsoft. Through interviews and surveys of developers as well as analysis of defect data, we provide insight and answers to four high level research questions that can help researchers design program analyzers meeting the needs of software developers.
First, we explore what barriers hinder the adoption of program analyzers, like poorly expressed warning messages. Second, we shed light on what functionality developers want from analyzers, including the types of code issues that developers care about. Next, we answer what non-functional characteristics an analyzer should have to be widely used, how the analyzer should fit into the development process, and how its results should be reported. Finally, we investigate defects in one of Microsoft's flagship software services, to understand what types of code issues are most important to minimize, potentially through program analysis
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