1,295 research outputs found

    Abundance anomalies of carbon and nitrogen in the IUE spectra of Algol-type interacting binaries

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    There are two primary ways in which the products of nucleosynthesis in stellar interiors may appear at the surface of a star. These are mixing and/or loss of the original unburned stellar envelope. In interacting binaries, overflow can contribute dramatically to envelope loss. The simplest abundance anomalies to be expected from nuclear burning of hydrogen, helium, or carbon would be under or over abundances H, He, C, O, Ne, and Mg. In addition, it is expected that carbon is initially severely depleted, while nitrogen is enhanced during hydrogen burning via the CNO cycle in stars above two solar masses. Other, more subtle anomalies are also expected, and elements heavier than magnesium can be created during very late evolution by nuclear burning in massive stars. Consequently, it is expected that abundance anomalies of various kinds should occur in interacting binaries where one or both stars have lost significant amounts of mass

    Mass flow in the interacting binary TX Ursae Majoris

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    Twenty-two far-ultraviolet and 23 near-ultraviolet high resolution IUE spectra of the interactive Algol-type binary TX Ursae Majoris (B8 V + F-K III-IV) were analyzed in order to determine the nature of the mass flow occurring in this system. Absorption features due to high-temperature ions of Si IV, C IV, and N V are always present. The resonance lines of Al III, Fe II, Mg II and Si IV show strong phase and secular variations indicative of gas streaming and circumstellar/circumbinary material. Radial velocities as high as 500 to 600 km/sec are present. The gas flow is particularly prominent in 1985 between phases 0.7 and 0.0. The system is more active than U Sagittae and as active as U Cephei

    Exploring the Drugs-Homicide Connection

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    Although research generally assumes a close relationship between drugs and violence, very little is known about the many different roles drugs can play in criminal events. Drug related as an event classification scheme is relatively common in homicide research, as well as other areas of inquiry, and is usually understood to be an important component in the causal processes of criminal events. Yet such classification schemes often suggest a simple, unidimensional construct. In reality, drug-related crimes are com-plex events. The purpose of this researchwas first to disaggregate the concept of drug-related homicide by providing an event classification scheme that conceptualizes the diverse roles drugs play in drug-related events.Acategorical coding scheme is presented that is similar to that proposed by Goldstein (1995) and later tested by Brownstein and colleagues (Brownstein & Goldstein, 1990; Brownstein, Baxi, Goldstein, & Ryan, 1992) that specifies three distinct types of homicide events. Included among these are (a) events that involved no evidence of illicit drugs associated with the homicide event, (b) those that involved the presence of drugs or drug use at the scene as well as events where either the victim and/or offender were buying or selling drugs (we term this peripherally drug-related homicides), and (c) events where the sale or use of drugswas the motivating feature of the homicide event. In some situations, there may be overlap between categories b and c; however, category c is distinct in that it includes features of motivation. The second purpose was to determine the relative importance of various situational and contextual characteristics of homicide events in understanding different types of drug-related events. Delineating these features will be an important step in filling in the gaps of knowledge about the assumed relationship between drugs and violence

    Mass loss in the interacting semi-detached binary delta librae

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    The interacting Algol-type binary Delta Librae (AOV + G: V) has been observed with the International Ultraviolet Explorer (IUE) satellite. More than fifty high resolution spectra in the far-ultraviolet and mid-ultraviolet spectrum have been analyzed in order to model the mass flow in the Delta Librae system. The resonance lines of Si IV and C IV are present in absorption and vary in strength both secularly and with phase. The radial velocities of the Si IV and C IV absorption lines generally follow the orbital motion of the primary star but deviate by typically a few tens of kilometers per second in the direction of the observer. The presence of Si IV and C IV features indicates the existence of a region considerably hotter than the normal AOV photosphere and, since these lines are present at all phases, this region must be fairly extensive. These results are interpreted in terms of a 'pseudo-photosphere' around the equatorial region of the AOV star, created by matter being accreted from the G-type companion. The widths of the Si IV and C IV absorption features imply that some of the matter lost by the G-star leaves the system entirely

    OCL Plus: Processes and Events in Object-Centred Planning

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    An important area in AI Planning is the expressiveness of planning domain specification languages such as PDDL, and their aptitude for modelling real applications. This paper presents OCLplus, an extension of a hierarchical object centred planning domain definition language, intended to support the representation of domains with continuous change. The main extension in OCLplus provides the capability of interconnection between the planners and the changes that are caused by other objects of the world. To this extent, the concept of event and process are introduced in the Hierarchical Task Network (HTN), object centred planning framework in which a process is responsible for either continuous or discrete changes, and an event is triggered if its precondition is met. We evaluate the use of OCLplus and compare it with a similar language, PDDL+

    An evaluation of the status of living collections for plant, environmental, and microbial research

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    Citation: McCluskey, K., Parsons, J. P., Quach, K., & Duke, C. S. (2017). An evaluation of the status of living collections for plant, environmental, and microbial research. Journal of Biosciences, 42(2), 321-331. https://doi.org/10.1007/s12038-017-9685-6While living collections are critical for biological research, support for these foundational infrastructure elements is inconsistent, which makes quality control, regulatory compliance, and reproducibility difficult. In recent years, the Ecological Society of America has hosted several National Science Foundation–sponsored workshops to explore and enhance the sustainability of biological research infrastructure. At the same time, the United States Culture Collection Network has brought together managers of living collections to foster collaboration and information exchange within a specific living collections community. To assess the sustainability of collections, a survey was distributed to collection scientists whose responses provide a benchmark for evaluating the resiliency of these collections. Among the key observations were that plant collections have larger staffing requirements and that living microbe collections were the most vulnerable to retirements or other disruptions. Many higher plant and vertebrate collections have institutional support and several have endowments. Other collections depend on competitive grant support in an era of intense competition for these resources. Opportunities for synergy among living collections depend upon complementing the natural strong engagement with the research communities that depend on these collections with enhanced information sharing, communication, and collective action to keep them sustainable for the future. External efforts by funding agencies and publishers could reinforce the advantages of having professional management of research resources across every discipline. © 2017 Indian Academy of Science

    X-ray and UV spectroscopy of Cygnus X-1 = HDE226868

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    Observations are presented of Cygnus X-1 with the solid-state spectrometer on the Einstein Observatory. The X-ray spectra of two intensity dips viewed near superior conjunction did not exhibit increased photoelectric absorption. Rather the data support a model in which an increase in the electron scattering optical depth modifies both the observed spectrum and the intensity. The characteristic temperature of the intervening material is greater than 5 x 10 to the 7th power K. These measurements were in part simultaneous with observations by IUE. The ultra violet spectrum and intensity remained relatively constant during an X-ray intensity dip

    Compliance with Australian stroke guideline recommendations for outdoor mobility and transport training by post-inpatient rehabilitation services: an observational cohort study

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    Background: Community participation is often restricted after stroke, due to reduced confidence and outdoor mobility. Australian clinical guidelines recommend that specific evidence-based interventions be delivered to target these restrictions, such as multiple escorted outdoor journeys. The aim of this study was to describe post-inpatient outdoor mobility and transport training delivered to stroke survivors in New South Wales, Australia and whether therapy differed according to type, sector or location of service provider. Methods: Using an observational retrospective cohort study design, 24 rehabilitation service providers were audited. Provider types included outpatient (n = 8), day therapy (n = 9), home-based rehabilitation (n = 5) and transitional aged care services (TAC, n = 2). Records of 15 stroke survivors who had received post-hospital rehabilitation were audited per service, for wait time, duration, amount of therapy and outdoor-related therapy. Results: A total of 311 records were audited. Median wait time for post-hospital therapy was 13 days (IQR, 5–35). Median duration of therapy was 68 days (IQR, 35–109), consisting of 11 sessions (IQR 4–19). Overall, a median of one session (IQR 0–3) was conducted outdoors per person. Outdoor-related therapy was similar across service providers,except that TAC delivered an average of 5.4 more outdoor-related sessions (95 % CI 4.4 to 6.4), and 3.5 more outings into public streets (95 % CI 2.8 to 4.3) per person, compared to outpatient services. Conclusion: The majority of service providers in the sample delivered little evidence-based outdoor mobility and travel training per stroke participant, as recommended in national stroke guidelines

    House prices and neighbourhood amenities: beyond the norm?

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    PURPOSE : Understanding the key locational and neighbourhood determinants and their accessibility is a topic of great interest to policymakers, planners and property valuers. In Northern Ireland, the high level of market segregation means that it is problematic to understand the nature of the relationship between house prices and the accessibility to services and prominent neighbourhood landmarks and amenities. Therefore, this paper aims to quantify and measure the (dis)amenity effects on house pricing levels within particular geographic housing sub-markets. DESIGN/METHODOLOGY/APPROACH : Most hedonic models are estimated using regression techniques which produce one coefficient for the entirety of the pricing distribution, culminating in a single marginal implicit price. This paper uses a quantile regression (QR) approach that provides a “more complete” depiction of the marginal impacts for different quantiles of the price distribution using sales data obtained from 3,780 house sales transactions within the Belfast Housing market over 2014. FINDINGS : The findings emerging from this research demonstrate that housing and market characteristics are valued differently across the quantile values and that conditional quantiles are asymmetrical. Pertinently, the findings demonstrate that ordinary least squares (OLS) coefficient estimates have a tendency to over or under specify the marginal mean conditional pricing effects because of their inability to adequately capture and comprehend the complex spatial relationships which exist across the pricing distribution. ORIGINALITY/VALUE : Numerous studies have used OLS regression to measure the impact of key housing market externalities on house prices, providing a single estimate. This paper uses a QR approach to examine the impact of local amenities on house prices across the house price distribution.http://www.emeraldinsight.com/loi/ijhmahj2019Taxatio

    Ceramic Substrates for High-temperature Electronic Integration

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    One of the most attractive ways to increase power handling capacity in power modules is to increase the operating temperature using wide-band-gap semiconductors. Ceramics are ideal candidates for use as substrates in high-power high-temperature electronic devices. The present article aims to determine the most suitable ceramic material for this application
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