NGC 5385, NGC 2664 and Collinder 21: three candidate Open Cluster Remnants

We present CCD UBVI photometric and medium/high resolution spectroscopic observations obtained in the field of the previously unstudied dissolving open cluster candidates NGC 5385, NGC 2664 and Collinder~21. Our analysis stands on the discussion of star counts, photometry, radial velocity distribution, and proper motions available from the Tycho~2 catalogue. All the three aggregates clearly emerge from the mean Galactic field, but, regrettably, the close scrutiny of proper motions and radial velocities reveals that we are not facing any physical group. Instead, what we are looking at are just chance alignments of a few bright unrelated stars. Our analysis casts some doubt on the Bica et al. (2001) criterion to look for Possible Open Cluster Remnants. It seems mandatory to define a better criterion to adopt for further investigations.Comment: 12 pages, 12 eps figures (7, 9 and 11 degraded in resolution), accepted for publication in Astronomy & Astrophysic

Trypanosomiase humaine africaine : étude d'un score de présomption de diagnostic au Congo

Une enquête cas-témoins a été réalisée au Congo afin de définir une grille de score de présomption de la maladie du sommeil à #T.b. gambiense$, basée sur une sélection de critères cliniques et épidémiologiques de la trypanosomiase, utilisable par les structures sanitaires périphériques. L'enquête a été réalisée sur 163 cas et 326 témoins. Les signes cliniques et les symptômes retenus sont :fièvre, céphalées, prurit et lésions de grattage, diarrhée, oedèmes, adénopathies cervicales, troubles du sommeil, troubles de l'appétit, troubles sexuels, psychisme, signes neurologiques et autres troubles cliniques mineurs. Les autres critères retenus sont les antécédents de trypanosomiase humaine africaine (THA) et l'existence d'un cheptel dans la concession. L'analyse des résultats confirme qu'il n'existe pas de critère ou groupe de critères pathognomoniques. Aucun des critères sélectionnés n'est suffisamment discriminant pour permettre une sélection des trypanosomés parmi les consultants. Une grille de score de présomption semble donc de peu d'utilité au niveau périphérique; ceci est d'autant plus vrai si l'on considère l'augmentation de la charge de travail. Le faible pouvoir discriminant des signes cliniques et des symptômes ainsi que des autres paramètres de la trypanosomiase africaine met en évidence la difficulté de mise en place d'une stratégie d'intégration efficiente en tant qu'outil diagnostique précoce. (Résumé d'auteur

A photometric study of the old open clusters Berkeley 73, Berkeley 75 and Berkeley 25

CCD BVI photometry of the faint open clusters Berkeley~73, Berkeley~75 and Berkeley~25 are presented. The two latter are previously unstudied clusters to our knowledge. While Berkeley~73 is found to be of intermediate-age (about 1.5 Gyr old), Berkeley~75 and Berkeley~25 are two old clusters, with ages larger than 3.0 Gyr. We provide also estimates of the clusters size. Very interestingly, all these clusters turn out to lie far away from the Galactic Center, at $R_{GC} \geq$ 16 kpc, and quite high onto the Galactic plane, at $|Z_{\odot}| \geq 1.5$ kpc. They are therefore important targets to probe the properties of the structure of the Galaxy in this direction, where the Canis Major over-density has been recently discovered to be located.Comment: 8 pages, 10 figures, in press in A&

Fifty Years of IMF Variation: The Intermediate-Mass Stars

I track the history of star count estimates of the Milky Way field star and open cluster IMFs, concentrating on the neglected mass range from 1 to 15 M${_\odot}$. The prevalent belief in a universal IMF appears to be without basis for this mass range. Two recent estimates of the field star IMF using different methods and samples give values of the average logarithmic slope $\Gamma$ between -1.7 and -2.1 in the mass range 1.1 to 4 M${_\odot}$. Two older estimates between 2 and 15 M${_\odot}$ disagree severely; the field IMF in this range is essentially unknown from star counts. Variations in $\Gamma$ among open cluster IMFs in this mass range have not decreased despite numerous detailed studies, even for studies using homogeneous data and reduction procedures and including only clusters with a significant mass range. These cluster variations \textit{might} be due to the combined effects of sampling, systematic errors, stellar evolution uncertainties, dynamical evolution, and unresolved binaries. If so, then the cluster data are consistent with a universal IMF, but are also consistent with sizeable variations. The cluster data do not allow an estimate of an average IMF or $\Gamma$ because the average depends on the choice of weighting procedure and other effects. If the spread in cluster IMFs is in excess of the effects listed above, real IMF variations must occur that do not depend much on physical conditions explored so far. The complexity of the star formation process seen in observations and simulations suggests that large realization-to-realization differences might be expected, in which case an individual cluster IMF would be in part the product of evolutionary contingency in star formation, and the function of interest is the probability distribution of IMF parameters.Comment: 18 pages, including 4 figures: invited talk presented at the conference on "IMF@50: The Stellar Initial Mass Function Fifty Years Later" held at Abbazia di Spineto, Siena, Italy, May 2004; to be published by Kluwer Academic Publishers, edited by E. Corbelli, F. Palla, and H. Zinnecke

Comparison of anaemia and parasitaemia as indicators of malaria control in household and EPI-health facility surveys in Malawi

<p>Abstract</p> <p>Background</p> <p>The World Health Organization has recommended that anaemia be used as an additional indicator to monitor malaria burden at the community level as malaria interventions are nationally scaled up. To date, there are no published evaluations of this recommendation.</p> <p>Methods</p> <p>To evaluate this recommendation, a comparison of anaemia and parasitaemia among 6-30 month old children was made during two repeated cross-sectional household (HH) and health facility (HF) surveys in six districts across Malawi at baseline (2005) and in a follow-up survey (2008) after a scale up of malaria control interventions.</p> <p>Results</p> <p>HH net ownership did not increase between the years (50.5% vs. 49.8%), but insecticide treated net (ITN) ownership increased modestly from 41.5% (95% CI: 37.2%-45.8%) in 2005 to 45.3% (95% CI: 42.6%-48.0%) in 2008. ITN use by children 6-30 months old, who were living in HH with at least one net, increased from 73.6% (95% CI:68.2%-79.1%) to 80.0% (95% CI:75.9%-84.1%) over the three-year period. This modest increase in ITN use was associated with a decrease in moderate to severe anaemia (Hb <8 g/dl) from 18.4% (95% CI:14.9%-21.8%) in 2005 to 15.4% (13.2%-17.7%) in 2008, while parasitaemia, measured as positive-slide microscopy, decreased from 18.9% (95% CI:14.7%-23.2%) to 16.9% (95% CI:13.8%-20.0%), a relative reduction of 16% and 11%, respectively. In HF surveys, anaemia prevalence decreased from 18.3% (95% CI: 14.9%-21.7%) to 15.4% (95% CI: 12.7%-18.2%), while parasitaemia decreased from 30.6% (95% CI: 25.7%-35.5%) to 13.2% (95% CI: 10.6%-15.8%), a relative reduction of 15% and 57%, respectively.</p> <p>Conclusion</p> <p>Increasing access to effective malaria prevention was associated with a reduced burden of malaria in young Malawian children. Anaemia measured at the HF level at time of routine vaccination may be a good surrogate indicator for its measurement at the HH level in evaluating national malaria control programmes.</p

On the recent star formation history of the Milky Way disk

We have derived the star formation history of the Milky Way disk over the last 2 Gyr from the age distribution diagram of a large sample of open clusters comprising more than 580 objects. By interpreting the age distribution diagram using numerical results from an extensive library of N-body calculations carried out during the last ten years, we reconstruct the recent star formation history of the Milky Way disk. Our analysis suggests that superimposed on a relatively small level of constant star formation activity mainly in small-N star clusters, the star formation rate has experienced at least 5 episodes of enhanced star formation lasting about 0.2 Gyr with production of larger clusters. This cyclic behavior seems to show a period of 0.4+/-0.1 Gyr.Comment: Abridged abstract. Accepted by New Astronomy. Major changes. A number of figures have been added in order to improve the discussion on error

Assessment of a treatment guideline to improve home management of malaria in children in rural south-west Nigeria

<p>Abstract</p> <p>Background</p> <p>Many Nigerian children with malaria are treated at home. Treatments are mostly incorrect, due to caregivers' poor knowledge of appropriate and correct dose of drugs. A comparative study was carried out in two rural health districts in southwest Nigeria to determine the effectiveness of a guideline targeted at caregivers, in the treatment of febrile children using chloroquine.</p> <p>Methods</p> <p>Baseline and post intervention knowledge, attitude and practice household surveys were conducted. The intervention strategy consisted of training a core group of mothers ("mother trainers") in selected communities on the correct treatment of malaria and distributing a newly developed treatment guideline to each household. "Mother trainers" disseminated the educational messages about malaria and the use of the guideline to their communities.</p> <p>Results</p> <p>Knowledge of cause, prevention and treatment of malaria increased with the one-year intervention. Many, (70.4%) of the respondents stated that they used the guideline each time a child was treated for malaria. There was a significant increase in the correct use of chloroquine from 2.6% at baseline to 52.3% after intervention among those who treated children at home in the intervention arm compared with 4.2% to 12.7% in the control arm. The correctness of use was significantly associated with use of the guideline. The timeliness of commencing treatment was significantly earlier in those who treated febrile children at home using chloroquine than those who took their children to the chemist or health facility (p < 0.005). Mothers considered the guideline to be explicit and useful. Mother trainers were also considered to be effective and acceptable.</p> <p>Conclusion</p> <p>The use of the guideline with adequate training significantly improved correctness of malaria treatment with chloroquine at home. Adoption of this mode of intervention is recommended to improve compliance with drug use at home. The applicability for deploying artemisinin-based combination therapy at the community level needs to be investigated.</p

Who attends antenatal care and expanded programme on immunization services in Chad, Mali and Niger? the implications for insecticide-treated net delivery

UNLABELLED: ABSTRACT: BACKGROUND: Malaria remains one of the largest public health problems facing the developing world. Insecticide-treated nets (ITNs) are an effective intervention against malaria. ITN delivery through routine health services, such as antenatal care (ANC) and childhood vaccination (EPI), is a promising channel of delivery to reach individuals with the highest risk (pregnant women and children under five years old). Decisions on whether to deliver ITNs through both channels depends upon the reach of each of these systems, whether these are independent and the effectiveness and cost effectiveness of each. Predictors of women attending ANC and EPI separately have been studied, but the predictors of those who attend neither service have not been identified. METHODS: Data from Chad, Mali and Niger demographic and health surveys (DHS) were analyzed to determine risk factors for attending neither service. A conceptual framework for preventative health care-seeking behaviour was created to illustrate the hierarchical relationships between the potential risk factors. The independence of attending both ANC and EPI was investigated. A multivariate model of predictors for non-attendance was developed using logistic regression. RESULTS: ANC and EPI attendance were found to be strongly associated in all three countries. However, 47% of mothers in Chad, 12% in Mali and 36% in Niger did not attend either ANC or EPI. Region, mother's education and partner's education were predictors of non-attendance in all three countries. Wealth index, ethnicity, and occupation were associated with non-attendance in Mali and Niger. Other predictors included religion, healthcare autonomy, household size and number of children under five. CONCLUSIONS: Attendance of ANC and EPI are not independent and therefore the majority of pregnant women in these countries will have the opportunity to receive ITNs through both services. Although attendance at ANC and EPI are not independent, delivery through both systems may still add incrementally to delivery through one alone. Therefore, there is potential to increase the proportion of women and children receiving ITNs by delivering through both of these channels. However, modelling is required to determine the level of attendance and incremental potential at which it's cost effective to deliver through both services