The complete larval development of a sesarmid crab from East Africa, Chiromantes eulimene (De Man 1895) was obtained through laboratory culture. It consists of five zoeal stages and a megalopa, ...followed by metamorphosis to the first juvenile crab. The morphology of all zoeal stages is revised and compared with previous descriptions. The megalopa and the first juvenile crab stage are, for the first time, fully described in detail and compared with those of other known species of the genus Chiromantes and further sesarmid crabs. The megalopal morphology of C. eulimene presents the typical combination of features that characterize sesarmid megalopae. The first crab stage is also similar to that of other sesarmid species, for which morphological descriptions are available.
The H.E.S.S. Galactic plane survey Angüner, E. O.; Arakawa, M.; Aubert, P. ...
Astronomy and astrophysics (Berlin),
04/2018, Letnik:
612
Journal Article
Recenzirano
Odprti dostop
We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) γ-rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the ...discovery of 16 new sources of VHE γ-rays. The High Energy Spectroscopic System (H.E.S.S.) Galactic plane survey (HGPS) was a decade-long observation program carried out by the H.E.S.S. I array of Cherenkov telescopes in Namibia from 2004 to 2013. The observations amount to nearly 2700 h of quality-selected data, covering the Galactic plane at longitudes from ℓ = 250° to 65° and latitudes |b|≤ 3°. In addition to the unprecedented spatial coverage, the HGPS also features a relatively high angular resolution (0.08° ≈ 5 arcmin mean point spread function 68% containment radius), sensitivity (≲1.5% Crab flux for point-like sources), and energy range (0.2–100 TeV). We constructed a catalog of VHE γ-ray sources from the HGPS data set with a systematic procedure for both source detection and characterization of morphology and spectrum. We present this likelihood-based method in detail, including the introduction of a model component to account for unresolved, large-scale emission along the Galactic plane. In total, the resulting HGPS catalog contains 78 VHE sources, of which 14 are not reanalyzed here, for example, due to their complex morphology, namely shell-like sources and the Galactic center region. Where possible, we provide a firm identification of the VHE source or plausible associations with sources in other astronomical catalogs. We also studied the characteristics of the VHE sources with source parameter distributions. 16 new sources were previously unknown or unpublished, and we individually discuss their identifications or possible associations. We firmly identified 31 sources as pulsar wind nebulae (PWNe), supernova remnants (SNRs), composite SNRs, or gamma-ray binaries. Among the 47 sources not yet identified, most of them (36) have possible associations with cataloged objects, notably PWNe and energetic pulsars that could power VHE PWNe.
An intrinsic gamma-ray burst afterglow
Long gamma-ray bursts (GRBs) are emitted by relativistic jets generated during the collapse of a massive star in a distant galaxy. The GRB itself lasts only a ...few seconds but is followed by an afterglow that can persist for hours or days. The H.E.S.S. Collaboration observed the afterglow of GRB 190829A, a nearby long GRB. The proximity of this burst allowed it to be detected at tera–electron volt energies that would otherwise be absorbed in the intergalactic medium. By analyzing the spectrum and light curve at x-ray and gamma-ray wavelengths, the authors show that the afterglow cannot be explained by standard models.
Science
, abe8560, this issue p.
1081
Observations of a nearby gamma-ray burst at tera–electron volt energies cannot be explained by standard models.
Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera–electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.
Over the past 25 years, the adult obesity rate in the U.S. has increased 70%, with obesity placing a disproportionate chronic disease burden on African Americans. Using Photovoice methodology, this ...study aimed to: (1) explore the social determinants contributing to obesity from the perspectives of residents of two low-income municipalities in Birmingham, Alabama with varying levels of segregation, (2) better understand residents' perceptions of contributors to obesity in their communities, and (3) examine residents' perceptions of interventions that might be effective in promoting positive change. Focus groups (N = 10) segmented by race and community were conducted by trained moderators. Transcriptions were analyzed by theoretical thematic analysis. The study design and data analysis analyses were guided by a conceptual framework based on the Social Determinants of Obesity model. Findings from this study lend support to the efficacy of the conceptual framework as a multilevel approach describing obesity disparities in the south. Regardless of community and race, participants believed that elements of their built environment, such as fast food restaurants and unsafe walking conditions, contributed to obesity, and that schools and churches should play an active role in addressing the issue.
Transport of newly synthesized cholesterol and vesicular stomatitis virus G protein from the endoplasmic reticulum to the
plasma membrane is interrupted by incubation at 15 degrees C. Under this ...condition the newly synthesized molecules accumulate
in both the endoplasmic reticulum (ER) and a subcellular vesicle fraction of low density called the lipid-rich vesicle fraction.
The material in the lipid-rich vesicle fraction appears to be a post-ER intermediate in the transport process to the plasma
membrane (PM). Although both newly synthesized cholesterol and G protein accumulate in this intermediate compartment at 15
degrees C, suggesting cotransport, treatment with Brefeldin A does not affect cholesterol transport to the PM, whereas it
strongly inhibits G protein transport. We conclude that cholesterol and G protein leave the ER in separate vesicles, the cholesterol
containing vesicles bypass the Golgi apparatus and proceed to the PM, whereas G protein containing vesicles follow the well
documented Golgi route to the cell surface.
This study examines the relationship between socioeconomic status and the likelihood of receiving medication for Attention Deficit Hyperactivity Disorder (ADHD) and then addresses the embodiment of ...the "ideal student," using the National Survey of Child's Health. We find that the construction of the ideal student and parents' higher income is correlated with higher odds of medication use for children and adolescents with ADHD. Furthermore, our results imply that structural inequalities in the current healthcare system increase the odds of upper-class children and adolescents receiving medication for ADHD. We find evidence that both severity of ADHD and younger ages increase the odds of receiving medication. We conclude with a discussion of the academic ethic, upper-class life, and future suggestions for research.
The nine-year H.E.S.S. Galactic Plane Survey (HGPS) has yielded the most uniform observation scan of the inner Milky Way in the TeV gamma-ray band to date. The sky maps and source catalogue of the ...HGPS allow for a systematic study of the population of TeV pulsar wind nebulae found throughout the last decade. To investigate the nature and evolution of pulsar wind nebulae, for the first time we also present several upper limits for regions around pulsars without a detected TeV wind nebula. Our data exhibit a correlation of TeV surface brightness with pulsar spin-down power Ė. This seems to be caused both by an increase of extension with decreasing Ė, and hence with time, compatible with a power law RPWN(Ė) ~Ė−0.65±0.20, and by a mild decrease of TeV gamma-ray luminosity with decreasing Ė, compatible with L1−10 TeV ~Ė0.59±0.21. We also find that the offsets of pulsars with respect to the wind nebula centre with ages around 10 kyr are frequently larger than can be plausibly explained by pulsar proper motion and could be due to an asymmetric environment. In the present data, it seems that a large pulsar offset is correlated with a high apparent TeV efficiency L1−10 TeV∕Ė. In addition to 14 HGPS sources considered firmly identified pulsar wind nebulae and 5 additional pulsar wind nebulae taken from literature, we find 10 HGPS sources that are likely TeV pulsar wind nebula candidates. Using a model that subsumes the present common understanding of the very high-energy radiative evolution of pulsar wind nebulae, we find that the trends and variations of the TeV observables and limits can be reproduced to a good level, drawing a consistent picture of present-day TeV data and theory.
An experiment was carried out to evaluate the hydroponic growth of Physalis angulate L. using desalinated wastewater in the composition of the nutritive solution, and to evaluate the chemical and ...sensorial traits of the fruits obtained by this production system. The control treatment solution had a conductivity level of 3.0 dS/m. The treatment solution tested had a conductivity level of 9.0 dS/m and was obtained by the use of desalinated wastewater. The first fruits were harvested at day 118 and the productivity was approximately 3.15 kg of fruits per plant in both treatments. The lipid levels did not significantly differed between treatments. The fatty acids in the lipid fraction were C18:2, C18:1, C16:0, C18:3. The total phenolic contents were 6.21 and 6.46 mg/100 g for the control treatment and for the tested treatment, respectively. The antioxidant activities using the methods ABTS and DPPH were 3.18 and 2.09 µmol/g for the control treatment and 3.40 and 2.26 µmol/g for the tested treatment. The sensorial test indicated that the general appearance and taste of the fruits were accepted by the testers who gave significantly superior grades for the taste of the fruits produced by the 9 dS/m treatment. The good productivity of the fruits, the fatty acids profile observed and the antioxidant properties of fruits, suggest that the production of Physalis angulate L. in hydroponic system NFT using desalinated wastewater is an attractive and sustainable option for residue recycling, allowing the production of a functional food well accepted by the consumers and with large benefits for human health.
The membrane P-glycoprotein (P170) is an ATP-hydrolyzing transmembrane pump, and elevated levels of P170, due to higher expression
with or without amplification of the multidrug resistance gene ...(mdr1), result in resistance to a variety of chemotherapeutic
agents in mammalian cells. The function of the P170 pump has been proposed as a protection against toxic substances present
in animal diets. Here we describe a Chinese hamster ovary cell line that was selected for resistance to a synthetic tripeptide,
N-acetyl-leucyl-leucyl-norleucinal (ALLN). This ALLN-resistant variant shows the classical multidrug resistance (MDR) phenotype,
including overexpression and amplification of the mdr1 gene. Additionally, a mouse embryo cell line overexpressing the transfected
mdr1 gene is likewise resistant to ALLN. Our results demonstrate that P170 is capable of transporting peptides and raise the
possibility that the mdr1 gene product or other MDR-like genes, present in the genome of mammalian cells, may be involved
in secretion of peptides or cellular proteins as is the case with the structurally similar hylB and ste6 gene products of
Escherichia coli and yeast, respectively.
Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material ...slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE; Formula: see text) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H.E.S.S.). The temporal profile of VHE emission is similar to that of lower-energy giga-electron volt emission, indicating a common origin, with a 2-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic rays to very high energies.
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