1,284 research outputs found
Knowledge and attitude of ethics committee (EC) members on bioethics and structure & function of EC in Bangladesh: A pilot study
Having scandalous unethical research practices in the mid and late 20th century, study protocols of biomedical research reviewed by the Ethics Committee (EC) has become the accepted international standard. The Declaration of Helsinki uniformly requires that all biomedical research involving human participants, including research on identifiable human material or data, should be approved by the EC. Today, concerns over the quality of the EC functions worldwide. There are research globally in this regard but no data are available from Bangladesh. Hence, we conducted a questionnaire based pilot study on knowledge and attitude of EC members on bioethics and structure & function of EC in Bangladesh
Standard Time Had a Rough Time in Bangor
The article discusses how, in 1883, the growing interstate railroad system decided the standardize time in locations throughout the United States. The City of Bangor Maine protested the change from the local time system in use prior to this time
The impact of construction and building materials on energy consumption on Saudi residential buildings
As a result of increasing population and buildings construction in Saudi Arabia, the demand for electricity is growing rapidly. There should be a greater focus on build-ings in the kingdom and several methods should be applied in order to reduce en-ergy consumption and create a lower carbon economy as residential buildings ac-count for about 70 percent of the total consumption. Saudi Arabia therefore ur-gently needs to develop residential buildings which use less energy and are more environmentally-friendly.
This study investigates the recent situation of Saudi residential buildings in terms of energy and building materials, using case studies. The main aim of this study is to identify suitable strategies and propose a number of recommendations that are useful in developing residential buildings in the Kingdom of Saudi Arabia.
This paper shows the importance of selecting the right, locally available, construc-tion materials for the external wall and thermal insulation in reducing energy con-sumption for the cooling load, by 59% after using the most appropriate construction materials for Saudi climate. Several methods were used in this research including IES energy simulation software in order to compare the most common external walls in the kingdom in terms of energy consumption and cooling load. Then, add-ing and selecting the right place for 0.50 m of polyurethane thermal insulation to the selected external wall to achieve the maximum reduction of cooling load.
It uses the example of a typical Saudi house design provided by the Saudi ministry of housing in three main cities in the kingdom: Jeddah, Riyadh and Dammam. Fur-thermore, the paper discusses the challenges facing the kingdom of Saudi Arabia in recent years and those of the future, such as a lack of the awareness amongst the Saudi population, and a lack of building standards and regulations
CCD BV survey of 42 open clusters
We present results of a photometric survey whose aim was to derive structural
and astrophysical parameters for 42 open clusters. While our sample is
definitively not representative of the total open cluster sample in the Galaxy,
it does cover a wide range of cluster parameters and is uniform enough to allow
for simple statistical considerations. BV wide-field CCD photometry was
obtained for open clusters for which photometric, structural, and dynamical
evolution parameters were determined. The limiting and core radii were
determined by analyzing radial density profiles. The ages, reddenings, and
distances were obtained from the solar metallicity isochrone fitting. The mass
function was used to study the dynamical state of the systems, mass segregation
effect and to estimate the total mass and number of cluster members. This study
reports on the first determination of basic parameters for 11 out of 42
observed open clusters. The angular sizes for the majority of the observed
clusters appear to be several times larger than the catalogue data indicate.
The core and limiting cluster radii are correlated and the latter parameter is
3.2 times larger on average. The limiting radius increases with the cluster's
mass, and both the limiting and core radii decrease in the course of dynamical
evolution. For dynamically not advanced clusters, the mass function slope is
similar to the universal IMF slope. For more evolved systems, the effect of
evaporation of low-mass members is clearly visible. The initial mass
segregation is present in all the observed young clusters, whereas the
dynamical mass segregation appears in clusters older than about log(age)=8.
Low-mass stars are deficient in the cores of clusters older than log(age)=8.5
and not younger than one relaxation time.Comment: 13 pages, 8 figure
Multicolor Photometry of the Vela Pulsar
Multicolor photometry of the Vela pulsar (PSR B0833-45), updated by recent
HST/WFPC2 observations obtained in the 555W, 675W and 814W filters, is
presented. The available data provide the best characterization so far of the
pulsar spectral shape, which is dominated by a flat power law continuum with
spectral index \alpha = -0.2 +/- 0.2, consistent with the extrapolation in the
optical domain of the power law component of the X-ray spectrum detected by
Chandra. In addition, a marginally significant dip (~ 3 sigma) seems to be
present at about 6500 AA. Spectroscopic observations with the VLT, now in
progress, will undoubtly provide a much better assessment of the reality and
characteristics of this feature.Comment: 4 pages, LaTex, 2 Postscript figures. Astronomy & Astrophysics,
accepte
Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial
<p>Abstract</p> <p>Background</p> <p>To evaluate the metabolic effects of two weight loss diets differing in macronutrient composition on features of dyslipidemia and post-prandial insulin (INS) response to a meal challenge in overweight/obese individuals.</p> <p>Methods</p> <p>This study was a parallel-arm randomized 4 mo weight loss trial. Adults (n = 50, 47 ± 7 y) matched on BMI (33.6 ± 0.6 kg/m<sup>2</sup>, <it>P </it>= 0.79) consumed energy restricted diets (deficit ~500 kcal/d): PRO (1.6 g.kg<sup>-1</sup>.d<sup>-1 </sup>protein and < 170 g/d carbohydrate) or CHO (0.8 g.kg<sup>-1</sup>.d<sup>-1 </sup>protein and > 220 g/d carbohydrate) for 4 mos. Meal challenges of respective diets were utilized for determination of blood lipids and post-prandial INS and glucose response at the beginning and end of the study.</p> <p>Results</p> <p>There was a trend for PRO to lose more weight (-9.1% vs. -7.3%, <it>P </it>= 0.07) with a significant reduction in percent fat mass compared to CHO (-8.7% vs. -5.7%; <it>P </it>= 0.03). PRO also favored reductions in triacylglycerol (-34% vs. -14%; <it>P </it>< 0.05) and increases in HDL-C (+5% vs. -3%; <it>P </it>= 0.05); however, CHO favored reduction in LDL-C (-7% vs. +2.5%; <it>P </it>< 0.05). INS responses to the meal challenge were improved in PRO compared to CHO (<it>P </it>< 0.05) at both 1 hr (-34.3% vs. -1.0%) and 2 hr (-9.2% vs. +46.2%), an effect that remained significant after controlling for weight or fat loss (both <it>P </it>< 0.05).</p> <p>Conclusion</p> <p>A weight loss diet with moderate carbohydrate, moderate protein results in more favorable changes in body composition, dyslipidemia, and post-prandial INS response compared to a high carbohydrate, low protein diet suggesting an additional benefit beyond weight management to include augmented risk reduction for metabolic disease.</p
MultiFit: a web server for fitting multiple protein structures into their electron microscopy density map
Advances in electron microscopy (EM) allow for structure determination of large biological assemblies at increasingly higher resolutions. A key step in this process is fitting multiple component structures into an EM-derived density map of their assembly. Here, we describe a web server for this task. The server takes as input a set of protein structures in the PDB format and an EM density map in the MRC format. The output is an ensemble of models ranked by their quality of fit to the density map. The models can be viewed online or downloaded from the website. The service is available at; http://salilab.org/multifit/ and http://bioinfo3d.cs.tau.ac.il/
Localizing INTEGRAL Sources with Chandra: X-Ray and Multi-Wavelength Identifications and Energy Spectra
We report on Chandra observations of 18 hard X-ray (>20 keV) sources
discovered with the INTEGRAL satellite near the Galactic plane. For 14 of the
INTEGRAL sources, we have uncovered one or two potential Chandra counterparts
per source. These provide soft X-ray (0.3-10 keV) spectra and sub-arcsecond
localizations, which we use to identify counterparts at other wavelengths,
providing information about the nature of each source. Despite the fact that
all of the sources are within 5 degrees of the plane, four of the IGR sources
are AGN (IGR J01545+6437, IGR J15391-5307, IGR J15415-5029, and IGR
J21565+5948) and four others are likely AGN (IGR J03103+5706, IGR J09189-4418,
IGR J16413-4046, and IGR J16560-4958) based on each of them having a strong IR
excess and/or extended optical or near-IR emission. We compare the X-ray and
near-IR fluxes of this group of sources to those of AGN selected by their 2-10
keV emission in previous studies and find that these IGR AGN are in the range
of typical values. There is evidence in favor of four of the sources being
Galactic (IGR J12489-6243, IGR J15293-5609, IGR J16173-5023, and IGR
J16206-5253), but only IGR J15293-5609 is confirmed as a Galactic source as it
has a unique Chandra counterpart and a parallax measurement from previous
optical observations that puts its distance at 1.56+/-0.12 kpc. The 0.3-10 keV
luminosity for this source is 1.4e32 erg/s, and its optical/IR spectral energy
distribution is well described by a blackbody with a temperature of 4200-7000 K
and a radius of 12.0-16.4 Rsun. These values suggest that IGR J15293-5609 is a
symbiotic binary with an early K-type giant and a white dwarf accretor. We also
obtained likely Chandra identifications for IGR J13402-6428 and IGR
J15368-5102, but follow-up observations are required to constrain their source
types.Comment: 17 pages, accepted by Ap
Deep optical observations of the central X-ray source in the Puppis A supernova remnant
X-ray observations reveiled a group of radio-silent isolated neutron stars
(INSs) at the centre of young supernova remnants (SNRs), dubbed central compact
objects or CCOs, with properties different from those of classical
rotation-powered pulsars. In at least three cases, evidence points towards CCOs
being low-magnetized INSs, born with slow rotation periods, and possibly
accreting from a debris disc of material formed out of the supernova event.
Understanding the origin of the diversity of the CCOs can shed light on
supernova explosion and neutron star formation models. Optical/infrared (IR)
observations are crucial to test different CCO interpretations. The aim of our
work is to perform a deep optical investigation of the CCO RX J0822.0-4300 in
the Puppis A SNR, one of the most poorly understood in the CCO family. By using
as a reference the Chandra X-ray coordinates of RX J0822.0-4300, we performed
deep optical observations in the B, V and I bands with the Very Large Telescope
(VLT). We found no candidate optical counterpart within 3 sigma of the computed
Chandra X-ray position down to 5 sigma limits of B~27.2, V~26.9, and I~25.6,
the deepest obtained in the optical band for this source. These limits confirm
the non-detection of a companion brighter than an M5 dwarf. At the same time,
they do not constrain optical emission from the neutron star surface, while
emission from the magnetosphere would require a spectral break in the
optical/IR.Comment: 4 pages, 2 figures, Astronomy and Astrophysics, accepte
Optical and X-ray observations of candidate isolated neutron stars in the G315.4-2.3 SNR
G315.4-2.3 is a young Galactic supernova remnant (SNR), whose identification
as the remains of a Type-II supernova (SN) explosion has been debated for a
long time. In particular, recent multi-wavelength observations suggest that it
is the result of a Type Ia SN, based on spectroscopy of the SNR shell and the
lack of a compact stellar remnant.However, two X-ray sources, one detected by
Einstein and ROSAT (Source V) and the other by Chandra (Source N) have been
proposed as possible isolated neutron star candidates. In both cases, no clear
optical identification was available and, therefore, we performed an optical
and X-ray study to determine the nature of these two sources. Based on Chandra
astrometry, Source V is associated with a bright V~14 star, which had been
suggested based on the less accurate ROSAT position. Similarly, from VLT
archival observations, we found that Source N is associated with a relatively
bright star (). These likely identifications suggest that both X-ray
sources cannot be isolated neutron stars.Comment: 4 pages, 4 figures, accepted for publication in MNRA
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