To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The goal of the present study was to examine the influence of community environment on the nutritional status (weight-for-age and height-for-age) of children (aged 0–59 months) in Bangladesh. In addition, we tested the association between specific characteristics of community environments and child nutritional status.
The data are from the nationally representative 2004 Bangladesh Demographic and Health Survey.
Respondents were ever-married women (aged 15–49 years) and their children (n 5731), residing in 361 communities. Child nutritional outcomes are physical measurements of weight-for-age and height-for-age in sd units. We considered the following attributes of community environments potentially related to child nutrition: (i) community water and sanitation infrastructure; (ii) availability of community health and education services; (iii) community employment and social participation; and (iv) education level of the community.
Multilevel regression analysis showed that the spatial distribution of maternal and child covariates did not entirely explain the between-community variation in child nutritional status. The education level of the community emerged as the strongest community-level predictor of child height-for-age (highest v. lowest tertile, β = 0·18 (se 0·07)) and weight-for-age (highest v. lowest tertile, β = 0·21 (se 0·06)). In the height-for-age model, community employment and social participation also emerged as being statistically significant (highest v. lowest tertile, β = 0·13 (se = 0·06)).
The community environment influences child nutrition in Bangladesh, and maternal- and child-level covariates may fail to capture the entire influence of communities. Interventions to reduce child undernutrition in developing countries should take into consideration the wider community context.
We devised a new method to estimate globular cluster absolute ages by adopting the knee of the bending of the lower main-sequence (MS) in the Near-Infrared (NIR) J, J - Ks color-magnitude diagram. The color difference between this feature and the Turn-Off point is strongly correlated to the cluster age. This method is marginally affected by distance and reddening uncertainties, and by the possible occurrence of differential reddening. Furthermore, the knee location does not depend on the cluster age and it is a robust theoretical prediction. We adopted accurate J, Ks-band photometry collected with both MAD/VLT and SOFI/NTT for the Galactic globular cluster NGC 3201 to identify the location of the knee at J~19.90 ±0.03 and J-Ks ~0.76±0.02 mag. The comparison with different sets of cluster isochrones, transformed adopting different Color–Temperature–Relations (CTRs), shows that the models are slightly redder than the observations for J > 19 mag. This difference could be due to the presence of a calibration drift or to a problem of the CTRs in this magnitude range.
We discuss how a wide field imager with very high spatial
resolution on a relatively small telescope–but located in an observing
site with very good seeing–might constrain the
fraction of binary stars in Galactic globular clusters. We also mention
the role that the new data might play in investigating advanced evolutionary
phases of low-mass stars. Moreover, we discuss the role that an Extremely
Large Telescope might have on the longstanding problem of cosmic distances
and stellar populations. In particular, we discuss the impact that the detection
of Cepheids in galaxies at the distance of the Coma cluster and of RR Lyrae
stars in galaxies at the distance of the Virgo cluster might have on the
calibration of secondary distance indicators.
We adopted uvby Strömgren photometry to investigate the metallicity distribution of ω Cen Red Giant (RG) stars. We provided a new empirical calibration of the Strömgren m1≡(v − b) − (b − y) metallicity index based on cluster stars. The new calibration has been applied to a sample of ω Cen RGs. The shape of the estimated metallicity distribution is clearly asymmetric, with a sharp cut-off at low metallicities ([Fe/H] < −2.0) and a metal-rich tail up to [Fe/H] ∼ 0.0. Two main metallicity peaks have been identified, around [Fe/H]≈ −1.9 and −1.3 dex, and a metal-rich shoulder at ≈ −0.2 dex.
Multi-object spectrographs available on 8-m class telescopes provide the unique opportunity to directly investigate the kinematical and chemical properties of significant samples of resolved stars in galaxies of the Local Group. We present here the first results concerning an extensive study of stellar populations of the Carina dSph galaxy, based on data collected with the multi-object spectrographs FORS2 and FLAMES, both available at VLT. Preliminary estimates concerning the radial velocity distributions of the different samples are presented.
The aim of this chapter is to provide basic information on the use of the technique of laser-induced breakdown spectroscopy (LIBS) for quantitative analysis. It begins with a discussion of the theoretical assumptions on the state of the plasma that must be made in order to ensure reliability of the analysis. A review is then presented of some of the methods developed to extract quantitative information from experimental LIBS data.
In 1997, Castle et al. stated that at the time only a limited number of studies had reported on the use of LIBS as a quantitative technique . This paucity of results was attributed to the inadequate level of the analytical figures of merit (accuracy, precision and detection limits) attainable by this technique in comparison with other well-established techniques. Since then, however, many papers have appeared in the literature reporting on the use of the LIBS technique for quantitative analysis. In fact, owing to the peculiar advantages of LIBS, including short measurement times, the ability to use samples without any pre-treatment and the capability for simultaneous multi-element detection, many researchers have focused their efforts on developing new methods for reliable LIBS-based quantitative analysis. Undoubtedly, in some particular situations (screening, in situ measurement, process monitoring, hostile environments, etc.) LIBS may be the technique of choice. Thus, the main research efforts have been aimed at exploiting the technique's potential and minimizing its drawbacks.
Most of the drawbacks of LIBS are, however, side effects of its intrinsic advantages.
We present first results concerning the detection of variable stars in the Carina dwarf Spheroidal from B, V images collected with the 4-m CTIO telescope. We show a sample of candidate variables spanning from the tip of the Red Giant Branch down to the Main Sequence turn off. Finally, we discuss the future photometric and spectroscopic developments of this project.
We present U, B, V, I (SUSI@NTT) and J,Ks (SOFI@NTT) photometry of the Large Magellanic Cloud (LMC) cluster Reticulum. The observing strategy and data reduction (DAOPHOTII/ALLFRAME) allowed us to reach an accuracy of the order of 0.01 – 0.03 mag in all the bands at limiting magnitudes typical of RR Lyrae stars. Reticulum hosts a sizable sample of RR Lyrae stars (32), and we supply an accurate distance estimate using the RR Lyrae K-band Period-Luminosity-Metallicity (PLZK) relation. This method presents several advantages when compared with the MV vs [Fe/H] relation, since it is only marginally affected by off-ZAHB evolutionary effects and reddening corrections.
Strong ionization of the gas medium has significant effects
in the process of medium-order harmonic generation. The combined
effect of neutral atom depletion and defocusing of the pump
beam due to the intensity-dependent density of free electrons,
significantly modifies the conversion characteristics and
efficiency. For moderate harmonic orders, the yield is optimized
for well-defined values of the pump laser intensity that do
not depend on the order or on the focusing geometry, but only
on the ionization potential of the gas. In particular focusing
conditions, the ionization-induced defocusing can effectively
guide the pump beam along channels of optimum intensity, thus
enhancing the overall conversion efficiency. We demonstrate
that a very simple model is able to reproduce all our experimental
results in a surprisingly good way.
Candidate RR Lyrae variables have been identified for the first time in four globular clusters of the Andromeda galaxy (M31). Using HST-WFPC2 archive observations we have found 2, 4, 11 and 8 RR Lyrae variables of both ab and c Bailey types in G11, G33, G64 and G322 (Sargent et al., 1977), respectively. These numbers are quite consistent with the horizontal branch morphology exhibited by the four clusters.
We present some preliminary results based on new observations of the variable stars belonging to the Carina Dwarf Galaxy (DG). Photometric data were collected with the two wide field imagers available at ESO (WFI@2.2.) and CTIO (4m prime focus).
We report new, as yet unpublished HST/WFPC2 V, I photometry of 9 globular clusters in M31. These are part of a total sample of 19 clusters on M31 with well observed CMDs from HST. The clusters have the full range of horizontal branch morphologies from blue HB to red clump, but none are found with an extreme (blue only) horizontal branch. Plots of HB type vs [Fe/H] are similar to those of Galactic clusters, including a hint of second parameter clusters. Sixteen halo fields adjacent to the observed clusters included in our images have been analysed. The M31 halo metallicity distribution peaks at [Fe/H]=-0.7 dex with a tail toward low metallicity, resembling the halo of NGC 5128; metal-rich giants appear to be centrally concentrated.
We report the results of measurements aimed to check
the phase lock of time-delayed, collinear, harmonic pulses
and to verify the possibility of performing Ramsey-like
spectroscopy in the XUV. We demonstrate that for harmonics
of medium order and for the peak intensities available
with our laser system, the generation of collinear phase-locked
harmonic pulses is indeed possible and that such pulses
can be used to achieve high-resolution spectroscopy in
the short-wavelength region.
Using observations from the Hubble Space Telescope archive, color-magnitude diagrams have been constructed for globular Cluster 4 in the Fornax dSph galaxy and its surrounding field. These diagrams extend below the main-sequence turnoffs and have yielded measurements of the ages of the populations. In particular, from our analysis Cluster 4 shows [Fe/H] ≃ 2.0, a value significantly lower than that derived for the Fornax field ([Fe/H] ≃ −1.40). Putting our results in the frame of the findings of Buonanno et al. (1998) for the Fornax clusters 1, 2, 3 and 5, a global analysis of the properties of Fornax stellar populations has been performed.
Email your librarian or administrator to recommend adding this to your organisation's collection.