314 research outputs found
Setting UBVRI Photometric Zero-Points Using Sloan Digital Sky Survey ugriz Magnitudes
We discuss the use of Sloan Digital Sky Survey (SDSS) ugriz point-spread
function (PSF) photometry for setting the zero points of UBVRI CCD images. From
a comparison with the Landolt (1992) standards and our own photometry we find
that there is a fairly abrupt change in B, V, R, & I zero points around g, r, i
~ 14.5, and in the U zero point at u ~ 16. These changes correspond to where
there is significant interpolation due to saturation in the SDSS PSF fluxes.
There also seems to be another, much smaller systematic effect for stars with
g, r > 19.5. The latter effect is consistent with a small Malmquist bias.
Because of the difficulties with PSF fluxes of brighter stars, we recommend
that comparisons of ugriz and UBVRI photometry should only be made for
unsaturated stars with g, r and i in the range 14.5 - 19.5, and u in the range
16 - 19.5. We give a prescription for setting the UBVRI zero points for CCD
images, and general equations for transforming from ugriz to UBVRI.Comment: 13 pages. 6 figures. Accepted for publication in the Astronomical
Journa
Are treatment guides and rational drug use policies adequately exploited in combating respiratory system diseases?
SummaryThe aim of the present study was to increase awareness regarding the rational use of medicines. The data were obtained via the Material Resources Management System Module of the Ministry of Health. For the appropriateness of treatments, the Global Initiative for Asthma, the Global Initiative for Chronic Obstructive Lung Disease, and the guidelines for the rational use of medicines were used. We also investigated whether any de-escalation method or physical exercise was performed. Statistical analyses were performed using descriptive statistics to determine the mean, standard deviation, and frequency. The results showed that healthcare providers ignored potential drug reactions or adverse interactions, and reflecting the lack of adherence to the current treatment guides, 35.8% irrational use of medicines was recorded. Thus, de-escalation methods should be used to decrease costs or narrow the antibiotic spectrum, antibiotic selection should consider the resistance patterns, culturing methods should be analyzed, and monotherapy should be preferred over combination treatments
Transformations between 2MASS, SDSS and BVRI photometric systems: bridging the near infrared and optical
We present colour transformations for the conversion of the {\em 2MASS}
photometric system to the Johnson-Cousins system and further into the
{\em SDSS} system. We have taken {\em SDSS} magnitudes of stars
measured with the 2.5-m telescope from Data Release 5 (DR5), and
and magnitudes from Stetson's catalogue and \citet{Cu03},
respectively. We matched thousands of stars in the three photometric systems by
their coordinates and obtained a homogeneous sample of 825 stars by the
following constraints, which are not used in previous transformations: 1) the
data are de-reddened, 2) giants are omitted, and 3) the sample stars selected
are of the highest quality. We give metallicity, population type, and
transformations dependent on two colours. The transformations provide absolute
magnitude and distance determinations which can be used in space density
evaluations at short distances where some or all of the {\em SDSS}
magnitudes are saturated. The combination of these densities with those
evaluated at larger distances using {\em SDSS} photometry will supply
accurate Galactic model parameters, particularly the local space densities for
each population.Comment: 11 pages, including 10 figures and 7 tables, accepted for publication
in MNRA
Transit Timing Analysis in the HAT-P-32 system
We present the results of 45 transit observations obtained for the transiting
exoplanet HAT-P-32b. The transits have been observed using several telescopes
mainly throughout the YETI network. In 25 cases, complete transit light curves
with a timing precision better than min have been obtained. These light
curves have been used to refine the system properties, namely inclination ,
planet-to-star radius ratio , and the ratio between
the semimajor axis and the stellar radius . First analyses by
Hartman et al. (2011) suggest the existence of a second planet in the system,
thus we tried to find an additional body using the transit timing variation
(TTV) technique. Taking also literature data points into account, we can
explain all mid-transit times by refining the linear ephemeris by 21ms. Thus we
can exclude TTV amplitudes of more than min.Comment: MNRAS accepted; 13 pages, 10 figure
Transit Timing Analysis in the HAT-P-32 System
We present the results of 45 transit observations obtained for the transiting exoplanet HATP- 32b. The transits have been observed using several telescopes mainly throughout the YETI (Young Exoplanet Transit Initiative) network. In 25 cases, complete transit light curves with a timing precision better than 1.4 min have been obtained. These light curves have been used to refine the system properties, namely inclination i, planet-to-star radius ratio Rp/Rs, and the ratio between the semimajor axis and the stellar radius a/Rs. First analyses by Hartman et al. suggests the existence of a second planet in the system, thus we tried to find an additional body using the transit timing variation (TTV) technique. Taking also the literature data points into account, we can explain all mid-transit times by refining the linear ephemeris by 21 ms. Thus, we can exclude TTV amplitudes of more than ∼1.5min
A Global Review on Innovative, Sustainable, and Effective Materials Composing Growing Media for Forest Seedling Production
Purpose of Review: The demand for forest tree seedlings is increasing globally, and Sphagnum peat moss is widely used as a component of growing media for container plant production. However, peat extraction is environmentally unsustainable. The forest nursery sector needs to switch to more sustainable alternatives to peat. This review aims to identify potential substitutes for peat by reviewing the worldwide literature on alternative materials for growing media in forest nurseries. Recent Findings: Most studies on alternative growing media focused on single plant species growing under local conditions, thereby limiting generalizations about the effectiveness of alternative materials for plant production. To our knowledge, no systematic reviews of scientific literature on the effectiveness of new, alternative-to-peat materials for enhancing plant growth and the associated growing media characteristics for the forest nursery sector are currently available. Summary: Most of the analyzed case studies focused on angiosperms (73.1%), with the majority of studies coming from tropical seasonal forests/savannas (36.5%), followed by woodlands/shrublands (31.6%), and temperate forests (15.0%) biomes. Compost was the most studied material (19.5%), followed by bark, other organic materials, and manure (9.8, 9.7, and 8.0%, respectively). Green and municipal wastes were the principal sources of compost (> 60%), while agriculture and green wastes were the first sources of other materials (> 90%). Tested materials were dependent on the geographic region. Thus, manure was the most tested material in Africa and South America, tree bark in North America, and compost in Europe, Asia, and Oceania. Alternative materials effectively provided optimal physicochemical characteristics of growing media and enhanced seedling nursery growth when compared with peat-based growing media in more than 60% of the case studies. This review helps to identify research gaps and, most importantly, provides the basis for the future application of alternative growing media materials in forest nursery management worldwide
Chemical gradients in the Milky Way from the RAVE data
Aims. We aim at measuring the chemical gradients of the elements Mg, Al, Si, and Fe along the Galactic radius to provide new constraints on the chemical evolution models of the Galaxy and Galaxy models such as the Besancon model. Thanks to the large number of stars of our RAVE sample we can study how the gradients vary as function of the distance from the Galactic plane.
Methods. We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by using the GALAXIA code, which is based on the Besancon model. The three samples were analysed by using the very same method for comparison purposes. We integrated the Galactic orbits and obtained the guiding radii (R-g) and the maximum distances from the Galactic plane reached by the stars along their orbits (Z(max)). We measured the chemical gradients as functions of R-g at different Z(max).
Results. We found that the chemical gradients of the RAVE and GCS samples are negative and show consistent trends, although they are not equal: at Z(max) < 0.4 kpc and 4.5 < R-g(kpc) < 9.5, the iron gradient for the RAVE sample is d[Fe/H]/dR(g) = -0.065 dex kpc(-1), whereas for the GCS sample it is d[Fe/H]/dR(g) = -0.043 dex kpc(-1) with internal errors of +/-0.002 and +/-0.004 dex kpc(-1), respectively. The gradients of the RAVE and GCS samples become flatter at larger Z(max). Conversely, the mock sample has a positive iron gradient of d[Fe/H]/dR(g) = +0.053 +/- 0.003 dex kpc(-1) at Z(max) < 0.4 kpc and remains positive at any Z(max). These positive and unrealistic values originate from the lack of correlation between metallicity and tangential velocity in the Besancon model. In addition, the low metallicity and asymmetric drift of the thick disc causes a shift of the stars towards lower R-g and metallicity which, together with the thin-disc stars with a higher metallicity and R-g, generates a fictitious positive gradient of the full sample. The flatter gradient at larger Z(max) found in the RAVE and the GCS samples may therefore be due to the superposition of thin-and thick-disc stars, which mimicks a flatter or positive gradient. This does not exclude the possibility that the thick disc has no chemical gradient. The discrepancies between the observational samples and the mock sample can be reduced by i) decreasing the density; ii) decreasing the vertical velocity; and iii) increasing the metallicity of the thick disc in the Besancon model
Absolute parameters of the eclipsing binary V821 Cas from UBVRI light curves and radial velocities
We present UBVRI photometric measurements and spectroscopic observations of
the double-lined eclipsing binary V821 Cas. The radial velocities were obtained
by means of the cross-correlation technique. Simultaneous analyses of the
multi-band light curves and RVs give the absolute parameters for the stars as:
M=2.050.07 M, M=1.630.06 M,
R=2.310.03 R, R=1.390.02 R, T=9
400400 K, and T=8 600400 K. Analysis of the O-C residuals
yielded an apsidal motion in the binary at a rate of
=0^{\degr}.0149\pm0^{\degr}.0023 cycle, corresponding
to an apsidal period of U=11819 yr. Subtracting the relativistic
contribution we find that =-2.590 which is in agreement with the
value predicted by theoretical models. Comparison with current stellar
evolution models gives an age of yr for the system.Comment: 11 pages, including 6 figures and 6 tables, accepted for publication
in MNRA
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