Abstract
Gamma-ray bursts (GRBs) are particle acceleration sites that can emit photons in the very high-energy (VHE) domain through nonthermal processes. From 2004 until 2018, the current generation ...of Imaging Atmospheric Cherenkov Telescopes (IACTs) did not detect any GRB in the VHE domain. However, from 2018 to 2020, five detections were reported. In this work, we try to solve the case of the missing VHE GBRs prior to 2018. We aim to identify GRBs that might have eluded VHE detection in past years by the H.E.S.S., MAGIC, and VERITAS IACTs. To do so, we study GRBs with known redshift detected by Swift from 2004 until June 2022. We first identify all GRBs that could have been observed by these IACTs since 2004, considering observation conditions and visibility constraints. We assume a relation between the X-rays and the VHE gamma rays based on the VHE GRBs detected to date and combine this with the redshift measurements, instrument response information, and observation conditions to predict the observed VHE gamma-ray flux from the Swift X-Ray Telescope measurements. We report findings on 12 bright low-redshift GRBs that we identify as most likely to have been detected in the VHE domain by current IACTs. The rate of IACT-detectable GRBs with ideal observation conditions is <1 VHE GRB per year with the current configuration. With its lower energy threshold and higher sensitivity, this rate increases to ∼4 VHE GRBs per year with the Cherenkov Telescope Array.
Context. In the context of large-scale structure formation, clusters of galaxies are located at the nodes of the cosmic web, and continue to accrete galaxies and groups along filaments. In some ...cases, they show a very large extension and a preferential direction. Brightest cluster galaxies (BCGs) are believed to grow through the accretion of many small galaxies, and their structural properties are therefore expected to vary with redshift. In some cases BCGs show an orientation comparable to that of the cluster to which they belong. Aims. We analyse the morphological properties of 38 BCGs from the DAFT/FADA and CLASH surveys, and compare the position angles of their major axes to the direction of the cluster elongation at large scale (several Mpc). Methods. The morphological properties of the BCGs were studied by applying the GALFIT software to HST images and fitting the light distribution with one or two Sérsic laws, or with a Nuker plus a Sérsic law. The cluster elongations at very large scale were estimated by computing density maps of red sequence galaxies. Results. The morphological analysis of the 38 BCGs shows that in 11 cases a single Sérsic law is sufficient to account for the surface brightness, while for all the other clusters two Sérsic laws are necessary. In five cases, a Nuker plus a Sérsic law give a better fit. For the outer Sérsic component, the effective radius increases with decreasing redshift, and the effective surface brightness decreases with effective radius, following the Kormendy law. An agreement between the major axis of the BCG and the cluster elongation at large scale within ±30 deg is found for 12 clusters out of the 21 for which the PAs of the BCG and of the large-scale structure can be defined. Conclusions. The variation with redshift of the effective radius of the outer Sérsic component agrees with the growing of BCGs by accretion of smaller galaxies from z = 0.9 to 0.2, and it would be interesting to investigate this variation at higher redshift. The directions of the elongations of BCGs and of their host clusters and large scale structures surrounding them agree for 12 objects out of 21, implying that a larger sample is necessary to reach more definite conclusions.
Abstract
Astro-COLIBRI is a novel tool that evaluates alerts of transient observations in real time, filters them by user-specified criteria, and puts them into their multiwavelength and ...multimessenger context. Through fast generation of an overview of persistent sources as well as transient events in the relevant phase space, Astro-COLIBRI contributes to an enhanced discovery potential of both serendipitous and follow-up observations of the transient sky. The software’s architecture comprises a Representational State Transfer Application Programming Interface, both a static and a real-time database, a cloud-based alert system, as well as a website and apps for iOS and Android as clients for users. The latter provide a graphical representation with a summary of the relevant data to allow for the fast identification of interesting phenomena along with an assessment of observing conditions at a large selection of observatories around the world.
Background
Detection and removal of colonic adenomatous polyps (CAP) decreases colorectal cancer (CRC) development, particularly with more or larger polyps or polyps with advanced villous/dysplastic ...histology. Immunosuppression following solid organ transplantation (SOT) may accelerate CAP development and progression compared to average-risk population but the benefit of earlier colonoscopic surveillance is unclear.
Aims
Study the impact of maintenance immunosuppression post-SOT on developmental timing, multiplicity and pathological features of CAP, by measuring incidence of advanced CAP (villous histology, size ≥ 10 mm, ≥ 3 polyps, presence of dysplasia) post-SOT and the incidence of newly diagnosed CRC compared to average-risk age-matched population.
Methods
Single-center retrospective cohort study of SOT recipients.
Results
295 SOT recipients were included and were compared with 291 age-matched average-risk controls. The mean interval between screening and surveillance colonoscopies between SOT and control groups was 6.3 years vs 5.9 years (
p
= 0.13). Post-SOT maintenance immunosuppression mean duration averaged 59.9 months at surveillance colonoscopy. On surveillance examinations, SOT recipients exhibited more advanced (≥ 10 mm) adenomas compared to matched controls (9.2% vs. 3.8%,
p
= 0.034; adjusted OR 2.38; 95% CI 1.07–5.30).
Conclusion
SOT recipients appear at higher risk for developing advanced CAP, suggesting that earlier surveillance should be considered.
This study aims to analyze and compare the postural balance between two aquatic sports where vertical vs. horizontal body positions (i.e., windsurfing vs. swimming) are key techniques for both ...sports.
Eight volunteer windsurfers and eight swimmers agreed to participate in this study. Each of the assessments was a 2D kinematic analysis of frontal and/or sagittal balance (i.e., in bipedal and/or unipedal stance) of the center of mass velocity on wobble board (Single Plane Balance Board) on hard and/or soft surface. Kinematic analysis was performed in 2D using two action-cams. Data were digitized using the video-based data analysis system SkillSpector.
The results showed that the ANOVA, with repeated measures on 1 factor, showed a significant difference (p<0.001) between groups (i.e., swimmers and windsurfers) in all variables and in the interaction between ground (i.e., hard and foam) and group (p<0.01) in all tests in sagittal plane. Furthermore, for the ground*group interaction, a study (i.e., paired t-test) of the difference between balance (i.e., in frontal and/or sagittal plane) on hard and soft ground for each group showed that windsurfers had no difference in body sway in frontal and/or sagittal plane between hard and soft surface in bipedal stance.
We concluded that the windsurfers showed better postural balance performances compared to swimmers in the bipedal posture on hard and soft ground. Also, the windsurfers presented a better stability level compared with the swimmers.
To create a diagnostic document describing the utilization of pre‐implantation genetic testing (PGT) in the absence of monitoring and regulation. Retrospective cohort study of couples undergoing PGT ...between 2004 and 2007 in Lebanon. The clinical indications for 192 PGT cycles performed during the study period were gender selection (96.3%), chromosomal aneuploidy (3.1%), and balanced translocation (0.5%). When gender selection was sought, the selection of a son was desired in 94.1% of cases. Of couples undergoing PGT for sex selection, 16.2% were childless, 8.6% had one child of the opposite gender, 28.1% had two same‐gender children, 29.7% had three same‐gender children, and 11.9% had four or more. Our findings demonstrate the morally questionable consequences of self‐regulated systems in which physicians are the sole gatekeepers of norms and ethics.
Use of rifampin is required for short-course treatment regimens for tuberculosis. Tuberculosis caused by isolates of M. tuberculosis with resistance to rifampin and susceptibility to isoniazid is ...unusual, but it has been recognized through surveillance. Patients with tuberculosis (cases) with rifampin mono-resistance were compared with HIV-matched controls with tuberculosis caused by a drug-susceptible isolate. A total of 77 cases of rifampin mono-resistant tuberculosis were identified in this multicenter study. Three were determined to be laboratory contaminants, and 10 cases had an epidemiologic link to a case with rifampin mono-resistant tuberculosis, suggesting primary acquisition of rifampin-resistant isolates. Of the remaining 64 cases and 126 controls, there was no difference between cases and controls with regard to age, sex, race, foreign birth, homelessness, or history of incarceration. Cases were more likely to have a history of prior tuberculosis than were controls. Of the 38 cases and 74 controls with HIV infection, there was no difference between cases and controls with regard to age, sex, race, foreign birth, homelessness, history of incarceration, or prior tuberculosis. Cases were more likely to have histories of diarrhea, rifabutin use, or antifungal therapy. Laboratory analysis of available isolates showed that there was no evidence of spread of a single clone of M. tuberculosis. Further studies are needed to identify the causes of the development of rifampin resistance in HIV-infected persons with tuberculosis and to develop strategies to prevent its emergence.
Freshwater vulnerability in the Levant region Al-Sibai, M; Droubi, A; Al-Ashkar, H
International journal of climate change strategies and management,
05/2012, Letnik:
4, Številka:
2
Journal Article
Recenzirano
Purpose - The purpose of this paper is to discuss freshwater vulnerability to environmental change, including climate change, in Levant countries.Design methodology approach - The paper uses the ...methodological guidelines prepared by UNEP and Peking University, using the fresh water vulnerability index (VI) for each country of the Levant region. The VI was calculated for a five-year period interval, i.e. 1985, 1990, 1995, 2000, 2005, and was predicted for the years 2020 and 2040 taking into consideration the expected impacts of climate change.Findings - The vulnerability of freshwater resources was explored by isolating strategically-important issues related to different functions (uses) of freshwater systems in the Levant region. All Levant countries are very vulnerable according to the adopted methodology (VI values are from 0.5-0.7), with Palestine being the worst case. The value of each parameter was calculated for five-year interval period and for each Levant country. The most dominant parameter was the water variation parameter (RSv), which is a natural factor and highlights how vulnerable the region is to climate change. The second most important parameter was the water exploitation pressures (DPs), which reflect the efforts of the countries to satisfy their water needs from the limited water resources. Cooperation and exchange of data and information at the regional level regarding the vulnerability of the region to climate change and measures for mitigation and adaptation could help in alleviating its impacts on the countries of the region.Originality value - This paper highlights that fresh water resources in Levant region are under increasing pressures due to human-made and natural reasons. High population growth and economic activities rates have placed extensive pressure on the already limited water resources. Moreover, the prevailing arid climate and the expected impact of climate change will decrease the fresh water availability.
An investigation involving mechanical testing and microstructural characterization was undertaken to examine the influence of moisture state at the time of testing on the performance (i.e., strength, ...toughness, and failure mode) of pulp fiber-cement composites. Samples, prepared with fiber volume fractions of 0, 1.2, and 2.0%, were tested in oven dry, air dry, and wet states. Both compressive and flexural strength were found to be greatest in the oven dry state, presumably due to increased fiber and matrix strength as well as increased fiber/cement bonding which occurs with the controlled removal of water. Flexural toughness, however, was decreased for oven dry samples, and greater fiber fracture (as opposed to the more ductile failure mode of fiber pull-out) was observed in the oven dry samples. It is proposed that this results from differential shrinkage in the fibers’ S1 and S2 layers and increased fiber/cement bonding with drying.
Celotno besedilo
Dostopno za:
DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This study aims to investigate the association of human leukocyte antigen (HLA) class II genes and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) with autoimmune thyroid diseases in the ...Lebanese population. A total of 128 patients with autoimmune thyroid disease (55 with Graves’ disease (GD) and 73 with Hashimoto’s thyroiditis (HT)) were typed for HLA DQA1 (0301 and 0501) and DQB1 (0201, 0302, and 0303) and for 49A/G CTLA-4 using PCR-based sequence-specific priming methods. A total of 186 matched controls were typed for the same alleles and compared to the diseased population. Results showed no significant differences in HLA DQB1*0201 or DQB1*0301 allelic frequencies or CTLA-4 polymorphisms between patients and controls. For GD, there was a weak association with HLA DQB1*0302 34.6% (19 of 55) vs. 21.5% (40 of 186),
P
= 0.048, odds ratio (OR) = 1.926, confidence interval (CI) = 0.999–3.715 and HLA DQB1*0302-DQA1*0501 haplotype 56.36% (31 of 55) vs. 40.8% (76 of 186),
P
= 0.042, OR = 1.870, CI = 1.018–3.433. For HT, the frequencies of DQB1*0302-DQA1*0501 haplotype 28.8% (21of 73) vs. 14.5% (27 of 186),
P
= 0.008, OR = 2.378, CI = 1.241–4.558 and DQB1*0302-DQA1*0301 haplotype 60.2% (44 of 73) vs. 38.7% (72 of 186),
P
= 0.002, OR = 2.402, CI = 1.381–4.180 were significantly higher in patients. On the other hand, weak association was found between HT and DQA1*0301 allele 32.9% (24 of 73) vs. 20.9% (39 of 186),
P
= 0.044, OR = 1.846, CI = 1.011–3.373. Findings show that DQB1*0302-DQA1*0501 and DQB1*0302-DQA1*0301 haplotypes may play a role in the pathogenesis of HT in the Lebanese population. For the 49A/G CTLA-4 polymorphism, no significant difference was found between patients and controls.
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