1,514 research outputs found

    Property Rights in a Fishery: Regulatory Change and Firm Performance

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    A new method is introduced and applied to analyse changes in productivity of firms harvesting a natural capital stock. The index-number technique decomposes the contributions of output prices, variable input prices, fixed inputs and productivity to firm profits, adjusted for changes in the natural capital stock. An application of the method is given using micro-level data from a common-pool resource. The indexes provide a ready-made comparison of all firms to the most profitable firm per unit of resource stock. Benchmarking with the decompositions also allows firms and regulators to determine what components are contributing most to economic profits and improve overall industry performance.productivity,profits,natural capital,index numbers

    Analysis and Design of Computer Networks Using a Web-Based DSS

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    Analyzing the performance of computer networks to improve their overall performance requires accounting for a large variety of inputs and operating characteristics, such as packet flow rates and sizes, device capabilities and interconnection capacities. A decision support system to analyze these multiple simultaneous variables is presented to assist network developers. Network architectures and demand patterns are accounted for and the underlying model that analyzes these patterns is discussed. A web based approach was utilized which has resulted in an accessible and scalable analytical tool

    The Mid-IR Contribution Of Dust Enshrouded Stars In Six Nearby Galaxies

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    We measure the integrated contributions of dusty AGB stars and other luminous red mid-IR sources to the mid-IR luminosities of 6 galaxies (M81, NGC 2403, NGC 300, M33 and the Magellanic Clouds). We find the dusty AGB stars whose mid-IR fluxes are dominated by dust rather than photospheric emission contribute from 0.6% (M81) to 5.6% (SMC) of the 3.6 micron flux and 1.0% (M81) to 10.1% (SMC) of the 4.5 micron flux. We find a trend of decreasing AGB contribution with increasing galaxy metallicity, luminosity and mass and decreasing SSFR. However, these galaxy properties are strongly correlated in our sample and the simplest explanation of the trend is galaxy metallicity. Bright, red sources other than dusty AGB stars represent a smaller fraction of the luminosity, ~1.2% at 3.6 microns, however their dust is likely cooler and their contributions are likely larger at longer wavelengths. Excluding the SMC, the contribution from these red sources correlates with the specific star formation rate as we would expect for massive stars. In total, after correcting for dust emission at other wavelengths, the dust around AGB stars radiates 0.1-0.8% of the bolometric luminosities of the galaxies. Thus, hot dust emission from AGB and other luminous dusty stars represent a small fraction of the total luminosities of the galaxies but a significant fraction of their mid-IR emissions.Comment: 9 pages, 6 figures, published in ApJ. For a brief video explaining the key results of this paper, see http://www.youtube.com/user/OSUAstronom

    The employee as 'Dish of the Day’:human resource management and the ethics of consumption

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    This article examines the ethical implications of the growing integration of consumption into the heart of the employment relationship. Human resource management (HRM) practices increasingly draw upon the values and practices of consumption, constructing employees as the ‘consumers’ of ‘cafeteria-style’ benefits and development opportunities. However, at the same time employees are expected to market themselves as items to be consumed on a corporate menu. In relation to this simultaneous position of consumer/consumed, the employee is expected to actively engage in the commodification of themselves, performing an appropriate organizational identity as a necessary part of being a successful employee. This article argues that the relationship between HRM and the simultaneously consuming/consumed employee affects the conditions of possibility for ethical relations within organizational life. It is argued that the underlying ‘ethos’ for the integration of consumption values into HRM practices encourages a self-reflecting, self-absorbed subject, drawing upon a narrow view of individualised autonomy and choice. Referring to Levinas’ perspective that the primary ethical relation is that of responsibility and openness to the Other, it is concluded that these HRM practices affect the possibility for ethical being

    An Early and Comprehensive Millimetre and Centimetre Wave and X-ray Study of SN 2011dh: a Non-Equipartition Blast Wave Expanding into a Massive Stellar Wind

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    Only a handful of supernovae (SNe) have been studied in multiwavelengths from the radio to X-rays, starting a few days after the explosion. The early detection and classification of the nearby Type IIb SN 2011dh/PTF 11eon in M51 provides a unique opportunity to conduct such observations. We present detailed data obtained at one of the youngest phase ever of a core-collapse SN (days 3–12 after the explosion) in the radio, millimetre and X-rays; when combined with optical data, this allows us to explore the early evolution of the SN blast wave and its surroundings. Our analysis shows that the expanding SN shock wave does not exhibit equipartition (ϵe/ϵB ∼ 1000), and is expanding into circumstellar material that is consistent with a density profile falling like R−2. Within modelling uncertainties we find an average velocity of the fast parts of the ejecta of 15 000 ± 1800 km s−1, contrary to previous analysis. This velocity places SN 2011dh in an intermediate blast wave regime between the previously defined compact and extended SN Type IIb subtypes. Our results highlight the importance of early (∼1 d) high-frequency observations of future events. Moreover, we show the importance of combined radio/X-ray observations for determining the microphysics ratio ϵe/ϵB

    A comprehensive study of GRB 070125, a most energetic gamma ray burst

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    We present a comprehensive multiwavelength analysis of the bright, long duration gamma-ray burst GRB 070125, comprised of observations in γ\gamma-ray, X-ray, optical, millimeter and centimeter wavebands. Simultaneous fits to the optical and X-ray light curves favor a break on day 3.78, which we interpret as the jet break from a collimated outflow. Independent fits to optical and X-ray bands give similar results in the optical bands but shift the jet break to around day 10 in the X-ray light curve. We show that for the physical parameters derived for GRB 070125, inverse Compton scattering effects are important throughout the afterglow evolution. While inverse Compton scattering does not affect radio and optical bands, it may be a promising candidate to delay the jet break in the X-ray band. Radio light curves show rapid flux variations, which are interpreted as due to interstellar scintillation, and are used to derive an upper limit of 2.4×10172.4 \times 10^{17} cm on the radius of the fireball in the lateral expansion phase of the jet. Radio light curves and spectra suggest a high synchrotron self absorption frequency indicative of the afterglow shock wave moving in a dense medium. Our broadband modeling favors a constant density profile for the circumburst medium over a wind-like profile (R2R^{-2}). However, keeping in mind the uncertainty of the parameters, it is difficult to unambiguously distinguish between the two density profiles. Our broadband fits suggest that \event is a burst with high radiative efficiency (>60> 60 %).Comment: 50 pages, 33 figures, sty file included, Appeared in 20 Aug 2008 edition of Astrophysical Journa

    A Comprehensive Study of GRB 070125, A Most Energetic Gamma-Ray Burst

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    We present a comprehensive multiwavelength analysis of the bright, long-duration gamma-ray burst GRB 070125, comprised of observations in gamma-ray, X-ray, optical, millimeter, and centimeter wave bands. Simultaneous fits to the optical and X-ray light curves favor a break on day 3.78, which we interpret as the jet break from a collimated outflow. Independent fits to optical and X-ray bands give similar results in the optical bands but shift the jet break to around day 10 in the X-ray light curve. We show that for the physical parameters derived for GRB 070125, inverse Compton scattering effects are important throughout the afterglow evolution. While inverse Compton scattering does not affect radio and optical bands, it may be a promising candidate to delay the jet break in the X-ray band. Radio light curves show rapid flux variations, which are interpreted as due to interstellar scintillation and used to derive an upper limit of 2.4 × 10 17 cm on the radius of the fireball in the lateral expansion phase of the jet. Radio light curves and spectra suggest a high synchrotron self-absorption frequency indicative of the afterglow shock wave moving in a dense medium. Our broadband modeling favors a constant density profile for the circumburst medium over a windlike profile (R -2). However, keeping in mind the uncertainty of the parameters, it is difficult to unambiguously distinguish between the two density profiles. Our broadband fits suggest that GRB 070125 is a burst with high radiative efficiency (>60%).R. A. C. was supported in part by NASA grant NNG06GJ33G

    Real-Time Detection and Rapid Multiwavelength Follow-up Observations of a Highly Subluminous Type II-P Supernova from the Palomar Transient Factory Survey

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    The Palomar Transient Factory (PTF) is an optical wide-field variability survey carried out using a camera with a 7.8 square degree field of view mounted on the 48-in Oschin Schmidt telescope at Palomar Observatory. One of the key goals of this survey is to conduct high-cadence monitoring of the sky in order to detect optical transient sources shortly after they occur. Here, we describe the real-time capabilities of the PTF and our related rapid multiwavelength follow-up programs, extending from the radio to the gamma-ray bands. We present as a case study observations of the optical transient PTF10vdl (SN 2010id), revealed to be a very young core-collapse (Type II-P) supernova having a remarkably low luminosity. Our results demonstrate that the PTF now provides for optical transients the real-time discovery and rapid-response follow-up capabilities previously reserved only for high-energy transients like gamma-ray bursts.Comment: ApJ, in press; all spectroscopic data available from the Weizmann Institute of Science Experimental Astrophysics Spectroscopy System (WISEASS; http://www.weizmann.ac.il/astrophysics/wiseass/

    Status of research and development of vaccines for Streptococcus pyogenes.

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    Streptococcus pyogenes is an important global pathogen, causing considerable morbidity and mortality, especially in low and middle income countries where rheumatic heart disease and invasive infections are common. There is a number of promising vaccine candidates, most notably those based on the M protein, the key virulence factor for the bacterium. Vaccines against Streptococcus pyogenes are considered as impeded vaccines because of a number of crucial barriers to development. Considerable effort is needed by key players to bring current vaccine candidates through phase III clinical trials and there is a clear need to develop a roadmap for future development of current and new candidates
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