The GRAPES-3 extensive air shower (EAS) array has been designed to study cosmic rays from 10
13
–10
16
eV. It employs 400 scintillator detectors spread across 25,000 m
2
, mainly of cone-type and ...fiber-type, each covering a 1 m
2
area. These detectors record EAS particle densities and arrival times, which are crucial for determining primary particle energy and direction. A decade (2013–2022) of EAS data is analyzed to investigate the dependence of particle densities on ambient temperature and atmospheric pressure. Notably, ambient temperature exhibits a delayed response, with a more pronounced delay in fiber-type detectors, while cone-type detectors exhibit a higher observed temperature coefficient. In contrast, atmospheric pressure instantly and uniformly affects both detector types, with Monte Carlo simulations backing the observed pressure coefficient. These findings established a reliable pressure coefficient for EAS within this distinctive energy range and contributed to the refinement of correction algorithms, ultimately improving particle density precision for more accurate shower parameter estimates.
Ultra-high-energy (UHE) cosmic neutrinos interacting with the Moon’s regolith generate particle showers that emit Askaryan radiation. This radiation can be observed from the Earth using ground-based ...radio telescopes like LOFAR. We simulate the effective detection aperture for UHE neutrinos hitting the Moon. Under the same assumptions, results from this work are in good agreement with previous analytic parameterizations and Monte Carlo codes. The dependence of the effective detection aperture on the observing parameters, such as observing frequency and minimum detection threshold, and lunar characteristics like surface topography have been studied. Using a Monte Carlo simulation, we find that the detectable neutrino energy threshold is lowered when we include a realistic treatment of the inelasticity, transmission coefficient, and surface roughness. Lunar surface roughness at large scales enhances the total aperture for higher observation frequencies (
ν
≥
1
GHz
) but has no significant effect on the LOFAR aperture. However, roughness at scales small compared to the wavelength reduces the aperture at all frequencies.
The involvement of host immunity in the gut microbiota-mediated colonization resistance to Clostridioides difficile infection (CDI) is incompletely understood. Here, we show that interleukin (IL)-22, ...induced by colonization of the gut microbiota, is crucial for the prevention of CDI in human microbiota-associated (HMA) mice. IL-22 signaling in HMA mice regulated host glycosylation, which enabled the growth of succinate-consuming bacteria Phascolarctobacterium spp. within the gut microbiome. Phascolarctobacterium reduced the availability of luminal succinate, a crucial metabolite for the growth of C. difficile, and therefore prevented the growth of C. difficile. IL-22-mediated host N-glycosylation is likely impaired in patients with ulcerative colitis (UC) and renders UC-HMA mice more susceptible to CDI. Transplantation of healthy human-derived microbiota or Phascolarctobacterium reduced luminal succinate levels and restored colonization resistance in UC-HMA mice. IL-22-mediated host glycosylation thus fosters the growth of commensal bacteria that compete with C. difficile for the nutritional niche.
For the discovery of novel Caspase-3 non-peptide inhibitors from Maybridge database, ligand and structure based virtual screening methods were used. One of the hits (AW01208), with good predictions ...was selected for synthesis and biological screening. This compound showed an inhibition activity against Caspase-3 in SKNH cell lines.
Caspase-3 belonging to a family of cysteine proteases is main executioner of apoptotic cascade pathway. The inhibitors of this protein are useful in the treatment of cardiomyopathy and neurodegenerative diseases. For the discovery of novel Caspase-3 non-peptide inhibitors from Maybridge database, ligand based and structure based virtual screening methods were used. Quantitative 3D pharmacophore models were generated using 25 known inhibitors of Caspase-3 and it was used as initial screen to retrieve the hits from the database. These compounds with high estimated activity were analyzed for drug like properties and docking studies were performed, to study the interaction between new hits and active site. One of the hits (AW01208), with good predictions was selected for synthesis and biological screening. This compound showed an inhibition activity against Caspase-3 in SKNH cell lines.
Low energy ground-based cosmic ray air shower experiments generally have energy threshold in the range of a few tens to a few hundreds of TeV. The shower observables are measured indirectly with an ...array of detectors. The atmospheric absorption of low energy secondaries limits their detection frequencies at the Earth’s surface. However, due to selection effects, a tiny fraction of low energy showers, which are produced in the lower atmosphere can reach the observational level. But, due to less information of shower observables, the reconstruction of these showers are arduous. Hence, it is believed that direct measurements by experiments aboard on satellites and balloon flights are more reliable at low energies. Despite having very small efficiency (
∼
0.1%) at low energies, the large acceptance (
∼
5m
2
sr) of GRAPES-3 experiment allows observing primary cosmic rays down below to
∼
1TeV and opens up the possibility to measure primary energy spectrum spanning from a few TeV to beyond cosmic ray knee (up to 10
16
eV), covering five orders of magnitude. The GRAPES-3 energy threshold for primary protons through Monte Carlo simulations are calculated, which gives reasonably good agreement with data. Furthermore, the total efficiencies and acceptance are also calculated for protons primaries. The ability of GRAPES-3 experiment to cover such a broader energy range may provide a unique handle to bridge the energy spectrum between direct measurements at low energies and indirect measurements at ultra-high energies.
Large scale anisotropy of cosmic rays (CRs) in the TeV-PeV energy region has been reported by several experiments located in the Northern Hemisphere as well as by the IceCube, and its surface array ...IceTop at the South Pole. The GRAPES-3 experiment in Ooty, India is designed to observe CRs in the energy range from a few TeV to over 10 PeV. Its near-equatorial location (11.4°N) provides a unique advantage for observations of CR anisotropy, overlapping with experiments in both the hemispheres. The GRAPES-3 consists of a dense array of ∼400 plastic scintillator detectors spread over an area of 25000 m2. It also contains a large area (560 m2) tracking muon detector which provides an excellent capability to discriminate γ-rays against CRs. It has recorded over 10 billion showers since its operation began in 2000. Measurement of CR anisotropy with a subset of this data is presented here.
The high density extensive air shower array along with large area (560 m
2
) muon telescope of GRAPES-3 at Ooty is used to make precise measurements of cosmic ray properties by using the secondaries ...produced through cascades in the Earth’s atmosphere. The observed particle density at detector level is affected by atmospheric effects primarily due to variations in the pressure and temperature. Here, an attempt is made to simulate these phenomena that can provide a deeper understanding of these effects. In this study, the pressure dependence of the observed particle densities at GRAPES-3 is simulated by varying the atmospheric profiles available in CORSIKA for proton showers in the energy range of 10
13
–10
16
eV. A comparative study of various combinations of hadronic interaction generators available in CORSIKA has been used to investigate the consistency of the results obtained and their broad implications have been intensely discussed.
The large area (560 m2) GRAPES-3 tracking muon telescope has been operating uninterruptedly at Ooty, India since 2001. Every day, it records 4 × 109 muons of ≥ 1 GeV with an angular resolution ...of ∼ 4°. The variation of atmospheric temperature affects the rate of decay of muons produced by the galactic cosmic rays (GCRs), which in turn modulates the muon intensity. By analyzing the GRAPES-3 data of six years (2005–2010), a small (amplitude ∼ 0.2%) seasonal variation (1 year (Yr) period) in the intensity of muons could be measured. The effective temperature ‘Teff’ of the upper atmosphere also displays a periodic variation with an amplitude of ∼ 1 K which was responsible for the observed seasonal variation in the muon intensity. At GeV energies, the muons detected by the GRAPES-3 are expected to be anti-correlated with Teff. The anti-correlation between the seasonal variation of Teff, and the muon intensity was used to measure the temperature coefficient αT by fast Fourier transform (FFT) technique. The magnitude of αT was found to scale with the assumed attenuation length ‘λ’ of the hadrons in the range λ = 80–180 g cm−2. However, the magnitude of the correction in the muon intensity was found to be almost independent of the value of λ used. For λ = 120 g cm−2 the value of temperature coefficient αT was found to be (−0.17±0.02)% K−1.
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