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
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
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
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
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 days before our first
detection. In the 24 hr after discovery, iPTF 16abc rose by 2 mag,
featuring a near-linear rise in flux for 3 days. Early spectra show
strong C II absorption, which disappears after 7 days. Unlike the
extensivelyobserved SN Ia SN 2011fe, the 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
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
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 mag. The maximum bolometric luminosity (from
optical and UV) was 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
, where =~57631.0 (MJD) and
days. The X-ray shows a marginal detection at erg/s (\textit{Swift} X-ray Telescope). No radio counterpart was
detected down to 3, providing upper limits for monochromatic radio
luminosity of erg/s and 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
H emission lines, with an FWHM of about 14,000 km/s and 10,000 km/s
respectively. He I lines are also detected at 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 650 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
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
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
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
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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