The central region of the Milky Way is one of the foremost locations to look for dark matter (DM) signatures. We report the first results on a search for DM particle annihilation signals using new ...observations from an unprecedented gamma-ray survey of the Galactic Center (GC) region, i.e., the Inner Galaxy Survey, at very high energies (& GSIM;100 GeV) performed with the H.E.S.S. array of five ground-based Cherenkov telescopes. No significant gamma-ray excess is found in the search region of the 2014-2020 dataset and a profile likelihood ratio analysis is carried out to set exclusion limits on the annihilation cross section (sigma v). Assuming Einasto and Navarro-Frenk-White (NFW) DM density profiles at the GC, these constraints are the strongest obtained so far in the TeV DM mass range. For the Einasto profile, the constraints reach (sigma v) values of 3.7 x 10-26 cm3 s-1 for 1.5 TeV DM mass in the W+W- annihilation channel, and 1.2 x 10-26 cm3 s-1 for 0.7 TeV DM mass in the tau+tau- annihilation channel. With the H.E.S.S. Inner Galaxy Survey, ground-based gamma-ray observations thus probe (sigma v) values expected from thermal-relic annihilating TeV DM particles.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
Context . HESS J1813–178 is a very-high-energy γ -ray source spatially coincident with the young and energetic pulsar PSR J1813–1749 and thought to be associated with its pulsar wind nebula (PWN). ...Recently, evidence for extended high-energy emission in the vicinity of the pulsar has been revealed in the Fermi Large Area Telescope (LAT) data. This motivates revisiting the HESS J1813–178 region, taking advantage of improved analysis methods and an extended dataset. Aims . Using data taken by the High Energy Stereoscopic System (H.E.S.S.) experiment and the Fermi -LAT, we aim to describe the γ -ray emission in the region with a consistent model, to provide insights into its origin. Methods . We performed a likelihood-based analysis on 32 hours of H.E.S.S. data and 12 yr of Fermi -LAT data and we fitted a spectro-morphological model to the combined datasets. These results allowed us to develop a physical model for the origin of the observed γ -ray emission in the region. Results . In addition to the compact very-high-energy γ -ray emission centred on the pulsar, we find a significant yet previously undetected component along the Galactic plane. With Fermi -LAT data, we confirm extended high-energy emission consistent with the position and elongation of the extended emission observed with H.E.S.S. These results establish a consistent description of the emission in the region from GeV energies to several tens of TeV. Conclusions . This study suggests that HESS J1813–178 is associated with a γ -ray PWN powered by PSR J1813–1749. A possible origin of the extended emission component is inverse Compton emission from electrons and positrons that have escaped the confines of the pulsar and form a halo around the PWN.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
The radio galaxy M 87 is a variable very-high energy (VHE) gamma-ray source, exhibiting three major flares, which were reported in 2005, 2008, and 2010. Despite extensive studies, the origin of the ...VHE gamma-ray emission is not yet fully understood. In this study, we investigate the VHE gamma-ray spectrum of M 87 during states of high gamma-ray activity, utilizing 20.2 h of H.E.S.S. observations. Our findings indicate a preference for a curved spectrum, characterized by a log-parabola model with extra-galactic background light (EBL) model above 0.3 TeV at the 4 σ level, compared to a power-law spectrum with EBL. We investigate the degeneracy between the absorption feature and the EBL normalization and derive upper limits on EBL models that are mainly sensitive in the wavelength range of 12.4 μm–40 μm.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time ...resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Firefighters are exposed to a range of harmful substances during firefighting. Exposure to fire smoke has been associated with a decrease in their lung function. However, the cause-effect ...relationship between those two factors is not yet demonstrated. This meta-analysis aimed to evaluate the potential associations between firefighters' occupational exposure and their lung function deterioration. Studies were identified from PubMed, Web of Science, Scopus and Science Direct databases (August 1990-March 2021). The studies were included when reporting the lung function values of Forced Expiratory Volume in 1 s (FEV
) or Forced Vital Capacity (FVC). The meta-analyses were performed using the generic inverse variance in R software with a random-effects model. Subgroup analysis was used to determine if the lung function was influenced by a potential study effect or by the participants' characteristics. A total of 5562 participants from 24 studies were included. No significant difference was found between firefighters' predicted FEV
from wildland, 97.64% (95% CI: 91.45-103.82%; I
= 99%), and urban fires, 99.71% (95% CI: 96.75-102.67%; I
= 98%). Similar results were found for the predicted FVC. Nevertheless, the mean values of firefighters' predicted lung function varied significantly among studies, suggesting many confounders, such as trials' design, statistical methods, methodologies applied, firefighters' daily exposure and career length, hindering an appropriate comparison between the studies.
Aging-associated, non-transmissible chronic diseases (NTCD) such as cancer, dyslipidemia, and neurodegenerative disorders have been challenged through several strategies including the consumption of ...healthy foods and the development of new drugs for existing diseases. Consumer health consciousness is guiding market trends toward the development of additives and nutraceutical products of natural origin. Fungi produce several metabolites with bioactivity against NTCD as well as pigments, dyes, antioxidants, polysaccharides, and enzymes that can be explored as substitutes for synthetic food additives. Research in this area has increased the yields of metabolites for industrial applications through improving fermentation conditions, application of metabolic engineering techniques, and fungal genetic manipulation. Several modern hyphenated techniques have impressively increased the rate of research in this area, enabling the analysis of a large number of species and fermentative conditions. This review thus focuses on summarizing the nutritional, pharmacological, and economic importance of fungi and their metabolites resulting from applications in the aforementioned areas, examples of modern techniques for optimizing the production of fungi and their metabolites, and methodologies for the identification and analysis of these compounds.
The aim of this study was to compare the effects of midazolam-ketamine alone or in combination with dexmedetomidine or tramadol in a constant rate infusion (CRI) on the minimum infusion rate (MIR) of ...propofol and the cardiorespiratory function in cats undergoing an ovariohysterectomy (OH). This was a prospective, randomised, blinded clinical study. Twenty-four healthy female mixed-breed cats were premedicated with ketamine and midazolam. Propofol was used for the induction and maintenance of the anaesthesia (starting at 18 mg/kg/h). Cats were assigned to groups (n = 8) to receive one of the following intravenous treatments: midazolam-ketamine group (MKG; ketamine 0.6 mg/kg/h); midazolam-ketamine-dexmedetomidine group MKDG; ketamine 0.6 mg/kg/h and dexmedetomidine loading dose (LD) 1 mg/kg, CRI 1 mg/kg/h) or midazolam-ketamine-tramadol group MKTG; ketamine 0.6 mg/kg/h and tramadol (LD 2 mg/kg, CRI 1 mg/kg/h). During the OH, the propofol infusion was adjusted based on the clinical signs to maintain adequate anaesthetic depth. Selected variables were measured before (T0) and after (T1) the anaesthesia induction and during six surgical time points (T2–T7). The mean arterial pressure was higher and the heart rate was lower in MKDG at T1 (than in MKG and MKTG). The mean ± SD MIR of propofol were 17.4 ± 3.2, 15.0 ± 2.8 and 12.6 ± 3.5 mg/kg/h for MKG, MKTG, and MKDG, respectively. We conclude that, compared to midazolam-ketamine alone, midazolam-ketamine-tramadol and midazolam-ketamine-dexmedetomidine reduced the MRI of propofol by 13.8% and 27.5%, respectively, without significant changes in the selected indicators.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Context.
Young massive stellar clusters are extreme environments and potentially provide the means for efficient particle acceleration. Indeed, they are increasingly considered as being responsible ...for a significant fraction of cosmic rays (CRs) that are accelerated within the Milky Way. Westerlund 1, the most massive known young stellar cluster in our Galaxy, is a prime candidate for studying this hypothesis. While the very-high-energy
γ
-ray source HESS J1646−458 has been detected in the vicinity of Westerlund 1 in the past, its association could not be firmly identified.
Aims.
We aim to identify the physical processes responsible for the
γ
-ray emission around Westerlund 1 and thus to understand the role of massive stellar clusters in the acceleration of Galactic CRs better.
Methods.
Using 164 h of data recorded with the High Energy Stereoscopic System (H.E.S.S.), we carried out a deep spectromorphological study of the
γ
-ray emission of HESS J1646−458. We furthermore employed H I and CO observations of the region to infer the presence of gas that could serve as target material for interactions of accelerated CRs.
Results.
We detected large-scale (∼2° diameter)
γ
-ray emission with a complex morphology, exhibiting a shell-like structure and showing no significant variation with
γ
-ray energy. The combined energy spectrum of the emission extends to several tens of TeV, and it is uniform across the entire source region. We did not find a clear correlation of the
γ
-ray emission with gas clouds as identified through H I and CO observations.
Conclusions.
We conclude that, of the known objects within the region, only Westerlund 1 can explain the majority of the
γ
-ray emission. Several CR acceleration sites and mechanisms are conceivable and discussed in detail. While it seems clear that Westerlund 1 acts as a powerful particle accelerator, no firm conclusions on the contribution of massive stellar clusters to the flux of Galactic CRs in general can be drawn at this point.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
Contents
The objective of this study was to detect the reasons of rooster's fertility decrease at 50 weeks of age. Therefore, the reproductive system of broiler breeder roosters was laparoscopic, ...macroscopic and histopathology evaluated, and a comparison of the anatomical aspect with the sperm analysis and birds’ age was realized. Cobb roosters (n = 59) were distributed into two groups (30 and 50 weeks). Evaluations were performed with laparoscopy, macroscopy and histopathology, and seminal quality, blood serum testosterone concentration and weight were also determined. The old roosters presented smaller testicle size, higher intensity epididymal lithiasis and lower testicle sperm production, compared to the young roosters. The use of the endoscope could easily distinguish a normal‐sized testicle than an atrophic one. Four old roosters with severe testicular atrophy did not show spermatogenesis, although three still had sperm in the ejaculate. This would falsely indicate a wrong diagnosis of normal fertility before the testicular atrophy took place. In conclusion, in addition to the weight increase with age, the testicular atrophy and impairment of sperm production seemed to be the main reason to the decrease in the rooster's fertility at 50 weeks of age. Therefore, the use of the laparoscopy as a way to detect the roosters with testicular atrophy before 50 weeks of age and their removal from them flock could be useful as a diagnostic tool to prevent the birds’ fertility loss.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The flat spectrum radio quasar 3C 279 is known to exhibit pronounced variability in the high-energy (100 MeV < E < 100 GeV) γ-ray band, which is continuously monitored with Fermi-LAT. During two ...periods of high activity in April 2014 and June 2015 target-of-opportunity observations were undertaken with the High Energy Stereoscopic System (H.E.S.S.) in the very-high-energy (VHE, E > 100 GeV) γ-ray domain. While the observation in 2014 provides an upper limit, the observation in 2015 results in a signal with 8.7σ significance above an energy threshold of 66 GeV. No VHE variability was detected during the 2015 observations. The VHE photon spectrum is soft and described by a power-law index of 4.2 ± 0.3. The H.E.S.S. data along with a detailed and contemporaneous multiwavelength data set provide constraints on the physical parameters of the emission region. The minimum distance of the emission region from the central black hole was estimated using two plausible geometries of the broad-line region and three potential intrinsic spectra. The emission region is confidently placed at r ≳ 1.7 × 1017 cm from the black hole, that is beyond the assumed distance of the broad-line region. Time-dependent leptonic and lepto-hadronic one-zone models were used to describe the evolution of the 2015 flare. Neither model can fully reproduce the observations, despite testing various parameter sets. Furthermore, the H.E.S.S. data were used to derive constraints on Lorentz invariance violation given the large redshift of 3C 279.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
PDF
