1,721,147 research outputs found
Inverse Compton Scattering onto BBR in High Energy Physics and Gamma (MeV-TeV) Astrophysics
No full textWe considered the Inverse Compton Scattering (ICS) of charged particles onto photons whose distribution is a Black Body Radiation (BBR) deriving the exact energy and angular differential distribution in the general case and in its most useful expansions. These results can be successfully applied in high energy accelerators experiments to evaluate the ICS contribution from the thermal photons in the cavity as well as in astrophysics where the ICS of cosmic rays plays a relevant role in a variety of phenomena. In particular we show how our formulae reproduce the ICS energy spectrum recently measured at LEP, how it could be considered a key tool in explaining the Gamma Ray Bursts (GRB) , SGRs energy spectrum. Finally we predicted the presence of a low gamma flux, nearly detectable at hundred of TeV from SNRs SN1006 as well as, at lower energy (tens TeV, due to gamma ray cascading in cosmic BBR), from relic extragalactic highest cosmic rays sources born by jets in AGN,as blazars 3C279,Mrk421,Mrk 501
A thermodynamic correction to the theory of competitive chemisorption of ions at surface sites with nonelectrostatic physisorption
No full textWe resolve a thermodynamic inconsistency in previous theoretical descriptions of the free energy of chemisorption (charge regulation) under conditions where nonelectrostatic physisorption is included, as applied to surface forces and particle-particle interactions. We clarify the role of nonelectrostatic ion physisorption energies and show that a term previously thought to represent physisorbed ion concentrations (activities) should instead be interpreted as a “partial ion activity” based solely on the electrostatic physisorption energy and bulk concentration, or alternatively on the nonelectrostatic physisorption energy and surface concentration. Second, the chemisorption energy must be understood as the change in chemical potential after subtracting the electrostatic energy, not subtracting the physisorption energy. Consequently, a previously reported specific ion nonelectrostatic physisorption contribution to the chemisorption free energy is annulled. We also report a correction to the calculation of surface charge. The distinction in “partial ion activity” evaluated from bulk concentration or from surface concentration opens a way to study nonequilibrium forces where chemisorption is in equilibrium with physisorbed ions but not in equilibrium with bulk ions, e.g., by a jump in ion concentrations
Gamma Jets by Precessing Neutron Star Jets in Galactic Binary Systems, GRBs, Superluminal Motion and The Twin Rings around SN1987A
No full textPrecessing Gamma Jets in extended and evaporating galactic halo as a source of GRB
No full textInverse Compton Scattering (ICS) by a relativistic electron beam jet at GeV energies (emitted by a compact object as a NS, BH,...), a NSJ, onto thermal BBR photons (from a nearby stellar companion) may originate a collinear gamma jet (GJ). Due to the binary system interaction the GJ precession would blaze suddenly toward the observer leading to a GRB event. The internal GJ cone structure is ruled by relativistic kinematics into a concentric onion-like sequence of photon rings, the softer in the external boundaries, the harder in the inner cone. The pointing and the crossing of such different GJ photon rings to the detector lead to a GRB hardness spectra evolution nearly corresponding to most observed ones. Moreover expected time integral spectra are also comparable with known GRB spectra. The total energy input of tens of thousands of such NSJ in an extended galactic halo, mainly cosmic rays electrons, should be reflected into the recent observational evidence (COMPTEL) of a diffused relic extended halo. Evidences of such precessing jets are offered by the discover of galactic superluminal sources, recent HH jets, SN1987A outer rings, Hourglass Nebula, planetary Egg Nebula, GROJ1744-28 binary X-rays pulsar
Dynamics and trends of drug dealing: a local labour system perspective
No full textThis study provides a dynamic analysis of illegal drug trafficking in the Italian region of Sardinia, using the Local Labour Systems (LLS, ISTAT)
framework. Data from major regional newspapers (January 2017 - De-cember 2022) were validated through institutional reports. A multivariate
biplot analysis reveals an increase in drug seizures and the Island’s role as a hub for national and international drug trade, facilitated by local
and traditional mafia organizations. Related crimes are also infiltrating the le-gal economy, particularly in the coastal real estate market. This study
high-lights the urgent need for targeted institutional and community strategies to protect younger people, who are increasingly involved in trafficking
Gamma Ray Bursts, Inverse Compton Scattering and the precessing Jets in Galactic Halo
No full textMost of the puzzling gamma ray burst (GRB) behaviours are successfully understood within a precessing gamma jet model born by Inverse Compton Scattering (ICS) of GeV electron beam jets onto thermal photons in binary systems. The ultrarelativistic electron jets are produced by fast spinning pulsars while the target photons are the ones emitted by a solar-like bound binary companion. The consequent beamed gamma ray jet precesses in space as a lighthouse and its ICS spectrum is well compatible with the oberved GRB spectra. The expected few thousands sources are located in an extended galactic halo. Few observed and identified sources as the Great Annihilator, the Soft Gamma Repeaters (SGR) and the recent superluminal sources in the galactic halo could be the possible associated candidates
Ultrahigh energy neutrino scattering onto relic light neutrinos in galactic halo as a possible source of highest energy extragalactic cosmic rays
No full textDiffuse relic neutrinos with light mass are transparent to ultra-high-energy (UHE) neutrinos at thousands of EeV, which are born through the photoproduction of pions by UHE protons on relic 2.73 K blackbody radiation (BBR), and originate in active galactic nuclei (AGNs) at cosmic distances. However, these UHE ν's may interact with others (mainly the heaviest: νμr, ντr, and respective antineutrinos) that are clustered into hot dark matter (HDM) galactic halos. UHE photons or protons, secondaries of ν-νr scattering, might be the final observed signatures of such high-energy chain reactions, and may be responsible for the highest energy extragalactic cosmic-ray (CR) events. Here we consider the conversion efficiency, ramifications, and energetics of these chain reactions for the 1991 October CR event at 320 EeV observed by the Fly's Eye detector in Utah. These quantities seem to be compatible with the distance, direction, and power (observed at MeV gamma energies) of the Seyfert galaxy MCG 8-11-11. The ν-νr interaction probability is favored by at least 3 orders of magnitude over a direct ν scattering onto Earth's atmosphere. Therefore, it may better explain the extragalactic origin of the puzzling 320 EeV event, while offering indirect evidence of a hot dark Galactic halo of light neutrinos (i.e., mν~tens of eV), probably of τ flavor
Salis (A.). Cathédrale Saint-Vincent de Chalon-sur-Saône, photos de R. Lacoste
No full textSalet Francis. Salis (A.). Cathédrale Saint-Vincent de Chalon-sur-Saône, photos de R. Lacoste. In: Bulletin Monumental, tome 123, n°4, année 1965. pp. 352-353
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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