1,176 research outputs found

    The growth, survival rate and reproductive characteristics of Artemia urmiana fed by Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. as feeding microalgae

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    This study was performed to compare the efficiency of six microalgae namely Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp., Chlorella sp. and Spirolina sp. on the growth, survival rate and reproduction efficacy in Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to the standard method. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. A highly significant difference (p<0.01) were found among three microalgae in terms of length growth, survival rates and reproduction characteristics in A. urmiana. In spite of higher length growth of A.urmiana fed on N. oculata than A. urmiana fed by T. suecica but survival and reproduction in the latter was better than the first treatment. In general, D. tertiolecta was more efficient than other microalgae examined in the present study on A. urmiana concerning not only to growth and survival but also to reproduction mode. So, it is preferred to feed A. urmiana

    Primary Healthcare System of Pakistan: Chal-lenges to Self-Management of Type 2 Diabetes

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    Abstract This review article is aimed at describing the primary healthcare system of Pakistan and its challenges in the face of epidemic of type 2 diabetes, focusing particularly on the middle-aged population of rural area of Pakistan. The main concern in Pakistan is that its middle-aged population is facing the onslaught of obesity and overweight due to lack of physical activity. In addition unhealthy eating habits making it more difficult for this population to control their weight. All these factors are contributing to a high risk of type 2 diabetes for the population of Pakistan. This article provides insight into the primary health care system of Pakistan and highlights its deficiencies by identifying that its primary healthcare system has a poor utilization of health care services, the poor accessibility to health system and poor management of diabetes by the healthcare system, gender disparity and inequity in the health care system. The primary objective of this study is to provide an overview of self-management of diabetes among the middle-aged population of Pakistan and to identify the overall deficiencies in the primary healthcare system, its delivery and access to the system, barriers to self-management of diabetes and quality of life in that region

    Using late-time optical and near-infrared spectra to constrain Type Ia supernova explosion properties

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    The late-time spectra of Type Ia supernovae (SNe Ia) are powerful probes of the underlying physics of their explosions. We investigate the late-time optical and near-infrared spectra of seven SNe Ia obtained at the VLT with XShooter at >>200 d after explosion. At these epochs, the inner Fe-rich ejecta can be studied. We use a line-fitting analysis to determine the relative line fluxes, velocity shifts, and line widths of prominent features contributing to the spectra ([Fe II], [Ni II], and [Co III]). By focussing on [Fe II] and [Ni II] emission lines in the ~7000-7500 \AA\ region of the spectrum, we find that the ratio of stable [Ni II] to mainly radioactively-produced [Fe II] for most SNe Ia in the sample is consistent with Chandrasekhar-mass delayed-detonation explosion models, as well as sub-Chandrasekhar mass explosions that have metallicity values above solar. The mean measured Ni/Fe abundance of our sample is consistent with the solar value. The more highly ionised [Co III] emission lines are found to be more centrally located in the ejecta and have broader lines than the [Fe II] and [Ni II] features. Our analysis also strengthens previous results that SNe Ia with higher Si II velocities at maximum light preferentially display blueshifted [Fe II] 7155 \AA\ lines at late times. Our combined results lead us to speculate that the majority of normal SN Ia explosions produce ejecta distributions that deviate significantly from spherical symmetry.Comment: 17 pages, 12 figure, accepted for publication in MNRA

    Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

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    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is when the SN could have first been detected by our survey, occurred only 0.15±0.070.150.15\pm_{0.07}^{0.15} days before our first detection. In the \sim24 hr after discovery, iPTF 16abc rose by \sim2 mag, featuring a near-linear rise in flux for \gtrsim3 days. Early spectra show strong C II absorption, which disappears after \sim7 days. Unlike the extensivelyobserved SN Ia SN 2011fe, the (BV)0(B-V)_0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56^{56}Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young \textit{normal} SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.Comment: 18 pages, 12 figures, accepted by Ap

    iPTF16fnl: a faint and fast tidal disruption event in an E+A galaxy

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    We present ground-based and \textit{Swift} observations of iPTF16fnl, a likely tidal disruption event (TDE) discovered by the intermediate Palomar Transient Factory (iPTF) survey at 66.6 Mpc. The lightcurve of the object peaked at absolute Mg=17.2M_g=-17.2 mag. The maximum bolometric luminosity (from optical and UV) was Lp  (1.0±0.15)×1043L_p~\simeq~(1.0\,\pm\,0.15) \times 10^{43} erg/s, an order of magnitude fainter than any other optical TDE discovered so far. The luminosity in the first 60 days is consistent with an exponential decay, with Le(tt0)/τL \propto e^{-(t-t_0)/\tau}, where t0t_0=~57631.0 (MJD) and τ15\tau\simeq 15 days. The X-ray shows a marginal detection at LX=2.41.11.9×1039L_X=2.4^{1.9}_{-1.1}\times 10^{39} erg/s (\textit{Swift} X-ray Telescope). No radio counterpart was detected down to 3σ\sigma, providing upper limits for monochromatic radio luminosity of νLν<2.3×1036\nu L_{\nu} < 2.3\times10^{36} erg/s and νLν<1.7×1037\nu L_{\nu}<1.7\times 10^{37} erg/s (VLA, 6.1 and 22 GHz). The blackbody temperature, obtained from combined \textit{Swift} UV and optical photometry, shows a constant value of 19,000 K. The transient spectrum at peak is characterized by broad He II and Hα\alpha emission lines, with an FWHM of about 14,000 km/s and 10,000 km/s respectively. He I lines are also detected at λλ\lambda\lambda 5875 and 6678. The spectrum of the host is dominated by strong Balmer absorption lines, which are consistent with a post-starburst (E+A) galaxy with an age of \sim650 Myr and solar metallicity. The characteristics of iPTF16fnl make it an outlier on both luminosity and decay timescales, as compared to other optically selected TDEs. The discovery of such a faint optical event suggests a higher rate of tidal disruptions, as low luminosity events may have gone unnoticed in previous searches.Comment: 14 pages, 11 figures, accepted for publication in Ap

    Recent trends in applying TPM to cloud computing

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    Trusted platform modules (TPM) have become important safe‐guards against variety of software‐based attacks. By providing a limited set of cryptographic services through a well‐defined interface, separated from the software itself, TPM can serve as a root of trust and as a building block for higher‐level security measures. This article surveys the literature for applications of TPM in the cloud‐computing environment, with publication dates comprised between 2013 and 2018. It identifies the current trends and objectives of this technology in the cloud, and the type of threats that it mitigates. Toward the end, the main research gaps are pinpointed and discussed. Since integrity measurement is one of the main usages of TPM, special attention is paid to the assessment of run time phases and software layers it is applied to.</p

    Environmental damage of different waste treatment scenarios by considering avoided emissions based on system dynamics modeling

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    This study aims to develop a comprehensive model for life cycle assessment and environmental damage cost calculations considering avoided emissions in different waste management scenarios using the system dynamics (SD) approach. Our analysis reveals that under the business-as-usual (BAU) scenario for the period 2020–2050, the total net greenhouse gas (GHG) emissions reach 12.5 Mt, with the highest environmental damage cost being USD 689 million. In contrast, an integrated management strategy encompassing recycling, composting, anaerobic digestion, and incineration results in a 195% reduction in net GHG emissions compared to the BAU Scenario. Concurrently, the environmental damage cost drops to USD 277 million, incorporating USD 347 million in savings, leading to a net environmental damage cost of USD −71 million. The findings affirm that accounting for emissions avoided across various treatment methods offers a more accurate estimate of environmental damage costs. Additionally, policies centered on integrated waste management are more likely to achieve sustainability. The study also demonstrates the utility of the SD approach in providing a holistic view of waste management systems and in evaluating the effectiveness of various policy strategies for sustainable waste management

    Using Enhanced Russell Model to Solve Inverse Data Envelopment Analysis Problems

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    This paper studies the inverse data envelopment analysis using the nonradial enhanced Russell model. Necessary and sufficient conditions for inputs/outputs determination are introduced based on Pareto solutions of multiple-objective linear programming. In addition, an approach is investigated to identify extra input/lack output in each of input/output components (maximum/minimum reduction/increase amounts in each a of input/output components). In addition, the following question is addressed: if among a group of DMUs, it is required to increase inputs and outputs to a particular unit and assume that the DMU maintains its current efficiency level with respect to other DMUs, how much should the inputs and outputs of the DMU increase? This question is discussed as inverse data envelopment analysis problems, and a technique is suggested to answer this question. Necessary and sufficient conditions are established by employing Pareto solutions of multiple-objective linear programming as well

    Introducing three species of Echinoids (order Echinoidea) in southern intertidal zone of Qeshm Island, the Persian Gulf

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    A one-year study (May 2007-April 2008) was undertaken to identify the echinoid species of intertidal sandy and rocky shores of the Qeshm Island. An intertidal sandy location and a rocky shore were surveyed in southern coasts of Qeshm Island, in northern Persian Gulf. Specimens were monthly collected along two 30m wide by 30 60m long (according to the tidal range) transects located approximately 300m apart, perpendicular to the sea, in each shore. Sampling was accomplished using 0.25m2 quadrat along each transect in the rocky shore, and by walking along nine 10×10-30m transects along each transect in the sandy shore. Three species of echinoids, belonging to 3 families were identified including: Clypeaster reticulatus, Diadema setosum and Echinometra mathaei. Identifications were verified by National Museum of Natural Science, Taiwan. While Clypeaster reticulatus belongs to sandy habitats, none of the identified species were observed in sandy location
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