The enigmatic core L1451-mm: a first hydrostatic core? or a hidden VeLLO?

We present the detection of a dust continuum source at 3-mm (CARMA) and 1.3-mm (SMA), and 12CO(2-1) emission (SMA) towards the L1451-mm dense core. These detections suggest a compact object and an outflow where no point source at mid-infrared wavelengths is detected using Spitzer. An upper limit for the dense core bolometric luminosity of 0.05 Lsun is obtained. By modeling the broadband SED and the continuum interferometric visibilities simultaneously, we confirm that a central source of heating is needed to explain the observations. This modeling also shows that the data can be well fitted by a dense core with a YSO and disk, or by a dense core with a central First Hydrostatic Core (FHSC). Unfortunately, we are not able to decide between these two models, which produce similar fits. We also detect 12CO(2-1) emission with red- and blue-shifted emission suggesting the presence of a slow and poorly collimated outflow, in opposition to what is usually found towards young stellar objects but in agreement with prediction from simulations of a FHSC. This presents the best candidate, so far, for a FHSC, an object that has been identified in simulations of collapsing dense cores. Whatever the true nature of the central object in L1451-mm, this core presents an excellent laboratory to study the earliest phases of low-mass star formation.Comment: 15 pages, 9 figures, emulateapj. Accepted by Ap

AN An ica-ensemble learning approach for prediction of uwb nlos signals data classification

Trapped human detection in search and rescue (SAR) scenarios poses a significant challenge in pervasive computing. This study addresses this issue by leveraging machine learning techniques, given their high accuracy. However, accurate identification of trapped individuals is hindered by the curse of dimensionality and noisy data. Particularly in non-line-of-sight (NLOS) situations during catastrophic events, the curse of dimensionality may lead to blind spots due to noise and uncorrelated values in detections. This research focuses on harmonizing information through wireless communication and identifying individuals in NLOS scenarios using ultra-wideband (UWB) radar signals. Employing independent component analysis (ICA) for feature extraction, the study evaluates classification performance using ensemble algorithms on both static and dynamic datasets. The experimental results demonstrate categorization accuracies of 88.37% for static data and 87.20% for dynamic data, highlighting the effectiveness of the proposed approach. Finally, this work can help scientists and engineers make instant decisions during SAR operations.Comment: 20 pages,4 figures, 1 algorithm and 3 table

Proximate, minerals and antinutrient assessment of the leaves and tenderstem of Leptadenia hastate (pers.) decne

The study evaluated the proximate, minerals and antinutrient contents of the plant Leptadenia hastata (Pers.) decne (Asclepiadaceae). Nutrient and antinutritional factors were determined using standard analytical methods and parameters subjected to statistical analysis. Manganese (Mn), Calcium (Ca) and Cobalt (Co) were found to be significantly (p<0.001) higher in the leaves when compared to the tender stem while Iron (Fe), Zinc (Zn) and Magnesium (Mg) were found to be significantly (p<0.001) higher in the tender stems when compared to the leaves. The percentages of Moisture content, Crude proteins and Total ash were found to be significantly (p<0.05) higher in the leaves when compared to the tender stem while crude fiber and Nitrogen Free Extract (NFE) was significantly (p<0.05) higher in the stem when compared to the leaves. Oxalate and phytic acid were anti nutrient found to be significantly (p<0.001) higher in the leaves when compared to the tender stem. However, Copper (Cu), Lead (Pb), Potassium (K) and Crude fat were not significantly (p>0.05) different when compared in the leaves and tender stem. Correlation analysis indicated that antinutrient contents in the tender stems will not affect the mineral absorption in the leaves while negative correlation between Fe and Cu in the stems could affect the absorption of iron. Therefore, Leptadenia hastata leave and tender stem consumed in soup and local salad in northern Nigeria proved to be rich in minerals and nutrients to support its dietary role as a consumed vegetable.Keywords: Leptadenia hastata, Minerals, Proximate, Antinutrients, Tender stems, Leave

Structure and decay of a proto-Y region in Tilapia, Oreochromis niloticus

Funding for Open Access provided by the UMD Libraries Open Access Publishing Fund.Sex-determination genes drive the evolution of adjacent chromosomal regions. Sexually antagonistic selection favors the accumulation of inversions that reduce recombination in regions adjacent to the sex-determination gene. Once established, the clonal inheritance of sex-linked inversions leads to the accumulation of deleterious alleles, repetitive elements and a gradual decay of sex-linked genes. This in turn creates selective pressures for the evolution of mechanisms that compensate for the unequal dosage of gene expression. Here we use whole genome sequencing to characterize the structure of a young sex chromosome and quantify sex-specific gene expression in the developing gonad. We found an 8.8 Mb block of strong differentiation between males and females that corresponds to the location of a previously mapped sex-determiner on linkage group 1 of Oreochromis niloticus. Putatively disruptive mutations are found in many of the genes within this region. We also found a significant female-bias in the expression of genes within the block of differentiation compared to those outside the block of differentiation. Eight candidate sex-determination genes were identified within this region. This study demonstrates a block of differentiation on linkage group 1, suggestive of an 8.8 Mb inversion encompassing the sex-determining locus. The enrichment of female-biased gene expression inside the proposed inversion suggests incomplete dosage compensation. This study helps establish a model for studying the early-to-intermediate stages of sex chromosome evolution.https://doi.org/10.1186/1471-2164-15-97

WASP-29b: A Saturn-sized transiting exoplanet

We report the discovery of a Saturn-sized planet transiting a V = 11.3, K4 dwarf star every 3.9 d. WASP-29b has a mass of 0.24+/-0.02 M_Jup and a radius of 0.79+/-0.05 R_Jup, making it the smallest planet so far discovered by the WASP survey, and the exoplanet most similar in mass and radius to Saturn. The host star WASP-29 has an above-Solar metallicity and fits a possible correlation for Saturn-mass planets such that planets with higher-metallicity host stars have higher core masses and thus smaller radii.Comment: 6 pages, submitted to ApJ

WASP-30b: a 61 Mjup brown dwarf transiting a V=12, F8 star

We report the discovery of a 61-Jupiter-mass brown dwarf, which transits its F8V host star, WASP-30, every 4.16 days. From a range of age indicators we estimate the system age to be 1-2 Gyr. We derive a radius (0.89 +/- 0.02 RJup) for the companion that is consistent with that predicted (0.914 RJup) by a model of a 1-Gyr-old, non-irradiated brown dwarf with a dusty atmosphere. The location of WASP-30b in the minimum of the mass-radius relation is consistent with the quantitative prediction of Chabrier & Baraffe (2000), thus confirming the theory.Comment: As accepted for publication in ApJL (6 pages, 2 figures, 3 tables

Hepatitis A seroprevalence in Western Cape Province South Africa: Are we in epidemiological transition

Background. Hepatitis A virus (HAV) is the most common cause of viral hepatitis worldwide. Hepatitis A vaccine is not included in the Expanded Programme on Immunisation in South Africa (EPI-SA), as the country is considered to be highly endemic for hepatitis A.Objectives. To determine the seroprevalence of hepatitis A infection in Western Cape Province (WCP), South Africa.Methods. We conducted a cross-sectional seroprevalence study in the 1 - 7-year age group in WCP. Our samples (N=482) were blood specimens left over after laboratory testing obtained from referral hospitals between August and October 2015. A Siemens enzyme immunoassay was used to test for total hepatitis A antibodies. We also analysed hepatitis A immunoglobulin G antibody results from the National Health Laboratory Service (NHLS) Disa*Lab database at Groote Schuur Hospital from 2009 to 2014, and included 2009 - 2014 acute hepatitis A (immunoglobulin M-positive) surveillance data from the National Institute for Communicable Diseases to look at trends in notified acute infections over the same period.Results. Our cross-sectional study showed 44.1% seroprevalence in the 1 - 7-year age group. Hepatitis A data from the NHLS database indicated a seroprevalence of <90% up to age 10 years, indicating intermediate endemicity. The surveillance data showed that a substantial number of symptomatic hepatitis A infections occurred in the 7 - 40-year age group, suggesting that an increasing proportion of the population is susceptible to HAV infection.Conclusions. These results suggest an urgent need for detailed evidence-based considerations to introduce hepatitis A vaccine into the EPI-SA

WASP-26b : a 1-Jupiter-mass planet around an early-G-type star

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-mag early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02 ± 0.03 MJup and radius of 1.32 ± 0.08 RJup. The host star, WASP-26, has a mass of 1.12 ± 0.03 M and a radius of 1.34 ± 0.06 R and is in a visual double with a fainter K-type star. The two stars are at least a common-proper motion pair with a common distance of around 250 ± 15 pc and an age of 6 ± 2 Gy

Will the starless cores in Chamaeleon I and III turn prestellar?

The nearby Chamaeleon molecular cloud complex is a good laboratory to study the process of low-mass star formation since it consists of three clouds with very different properties. Cha III does not show any sign of star formation, while star formation has been very active in Cha I and may already be finishing. Our goal is to determine whether star formation can proceed in Cha III, and to compare the results to our recent survey of Cha I. We used the Large APEX Bolometer Array (LABOCA) to map Cha III in dust continuum emission at 870 micron. 29 sources are extracted from the map, all of them being starless. The starless cores are found down to a visual extinction of 1.9 mag, in marked contrast with other molecular clouds, including Cha I. Apart from this difference, the Cha III starless cores share very similar properties with those found in Cha I. At most two sources have a mass larger than the critical Bonnor-Ebert mass, which suggests that the fraction of prestellar cores is very low, even lower than in Cha I. Only the most massive sources are candidate prestellar cores, in agreement with the correlation found earlier in the Pipe nebula. The mass distribution of the 85 starless cores of Cha I and III that are not candidate prestellar cores is consistent with a single power law down to the 90% completeness limit, with an exponent close to the Salpeter value. A fraction of the starless cores in Cha I and III may still grow in mass and become gravitationally unstable. Based on predictions of numerical simulations of turbulent molecular clouds, we estimate that at most 50% and 20% of the starless cores of Cha I and III, respectively, may form stars. The LABOCA survey reveals that Cha III, and Cha I to some extent too, is a prime target to study the formation of prestellar cores, and thus the onset of star formation. (abridged).Comment: Accepted for publication in A&A. 22 pages, 16 figures, 4 tables. A version with high-resolution figures is available on request to the first autho

Factors Affecting the Radii of Close-in Transiting Exoplanets

The radius of an exoplanet may be affected by various factors, including irradiation, planet mass and heavy element content. A significant number of transiting exoplanets have now been discovered for which the mass, radius, semi-major axis, host star metallicity and stellar effective temperature are known. We use multivariate regression models to determine the dependence of planetary radius on planetary equilibrium temperature T_eq, planetary mass M_p, stellar metallicity [Fe/H], orbital semi-major axis a, and tidal heating rate H_tidal, for 119 transiting planets in three distinct mass regimes. We determine that heating leads to larger planet radii, as expected, increasing mass leads to increased or decreased radii of low-mass (<0.5R_J) and high-mass (>2.0R_J) planets, respectively (with no mass effect on Jupiter-mass planets), and increased host-star metallicity leads to smaller planetary radii, indicating a relationship between host-star metallicity and planet heavy element content. For Saturn-mass planets, a good fit to the radii may be obtained from log(R_p/R_J)=-0.077+0.450 log(M_p/M_J)-0.314[Fe/H]+0.671 log(a/AU)+0.398 log(T_eq/K). The radii of Jupiter-mass planets may be fit by log(R_p/R_J)=-2.217+0.856 log(T_eq/K)+0.291 log(a/AU). High-mass planets' radii are best fit by log(R_p/R_J)=-1.067+0.380 log(T_eq/K)-0.093 log(M_p/M_J)-0.057[Fe/H]+0.019 log(H_tidal/1x10^{20}). These equations produce a very good fit to the observed radii, with a mean absolute difference between fitted and observed radius of 0.11R_J. A clear distinction is seen between the core-dominated Saturn-mass (0.1-0.5M_J) planets, whose radii are determined almost exclusively by their mass and heavy element content, and the gaseous envelope-dominated Jupiter-mass (0.5-2.0M_J) planets, whose radii increase strongly with irradiating flux, partially offset by a power-law dependence on orbital separation.Comment: 14 pages, 14 figures, accepted in A&