Mahidol University

About: Mahidol University is a education organization based out in Bangkok, Nakhon Pathom, Thailand. It is known for research contribution in the topics: Population & Malaria. The organization has 23758 authors who have published 39761 publications receiving 878781 citations.

First data release of the Hyper Suprime-Cam Subaru Strategic Program

Abstract: This paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg|$^2$| in all five broad-band filters (⁠|$grizy$|⁠) to the nominal survey exposure (10 min in |$gr$| and 20 min in |$izy$|⁠). Partially observed areas are also included in the release; about 1100 deg|$^2$| is observed in at least one filter and one exposure. The median seeing in the i-band is |${0_{.}^{\prime \prime }6}$|⁠, demonstrating the superb image quality of the survey. The Deep (26 deg|$^2$|⁠) and UltraDeep (4 deg|$^2$|⁠) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of |$i\sim 28$| at |$5 \, \sigma$| for point sources. In addition to the broad-band data, narrow-band data are also available in the Deep and UltraDeep fields. This release includes a major update to the processing pipeline, including improved sky subtraction, PSF modeling, object detection, and artifact rejection. The overall data quality has been improved, but this release is not without problems; there is a persistent deblender problem as well as new issues with masks around bright stars. The user is encouraged to review the issue list before utilizing the data for scientific explorations. All the image products as well as catalog products are available for download. The catalogs are also loaded into a database, which provides an easy interface for users to retrieve data for objects of interest. In addition to these main data products, detailed galaxy shape measurements withheld from Public Data Release 1 (PDR1) are now available to the community. The shape catalog is drawn from the S16A internal release, which has a larger area than PDR1 (160 deg|$^2$|⁠). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/.

Intracontinental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa

Abstract: A highly invasive form of non-typhoidal Salmonella (iNTS) disease has recently been documented in many countries in sub-Saharan Africa. The most common Salmonella enterica serovar causing this disease is Typhimurium (Salmonella Typhimurium). We applied whole-genome sequence-based phylogenetic methods to define the population structure of sub-Saharan African invasive Salmonella Typhimurium isolates and compared these to global Salmonella Typhimurium populations. Notably, the vast majority of sub-Saharan invasive Salmonella Typhimurium isolates fell within two closely related, highly clustered phylogenetic lineages that we estimate emerged independently ∼52 and ∼35 years ago in close temporal association with the current HIV pandemic. Clonal replacement of isolates from lineage I by those from lineage II was potentially influenced by the use of chloramphenicol for the treatment of iNTS disease. Our analysis suggests that iNTS disease is in part an epidemic in sub-Saharan Africa caused by highly related Salmonella Typhimurium lineages that may have occupied new niches associated with a compromised human population and antibiotic treatment.

Two Nonrecombining Sympatric Forms of the Human Malaria Parasite Plasmodium ovale Occur Globally

Abstract: Background: Malaria in humans is caused by apicomplexan parasites belonging to 5 species of the genus Plasmodium. Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease is not known. Dimorphism in defined genes has led to P. ovale parasites being divided into classic and variant types. We hypothesized that these dimorphs represent distinct parasite species. Methods: Multilocus sequence analysis of 6 genetic characters was carried out among 55 isolates from 12 African and 3 Asia-Pacific countries. Results: Each genetic character displayed complete dimorphism and segregated perfectly between the 2 types. Both types were identified in samples from Ghana, Nigeria, Sao Tome, Sierra Leone, and Uganda and have been described previously in Myanmar. Splitting of the 2 lineages is estimated to have occurred between 1.0 and 3.5 million years ago in hominid hosts. Conclusions: We propose that P. ovale comprises 2 nonrecombining species that are sympatric in Africa and Asia. We speculate on possible scenarios that could have led to this speciation. Furthermore, the relatively high frequency of imported cases of symptomatic P. ovale infection in the United Kingdom suggests that the morbidity caused by ovale malaria has been underestimated.