Energy spectra of proton and nuclei of primary cosmic rays in energy region 10 TeV/particle

To investigate the chemical composition of primary cosmic rays, several emulsion chambers were exposed at a 10.8 g/sq cm. depth in the stratosphere. Each chamber has the area of 0.92x0.46 sq m. and the depth of 14 c.u. The exposure time of chambers processed by now is 260 hours. The detecting layers were X-ray films and nuclear emulsions, which allowed to measure an energy of cascade and a type of primary particle. Results and techniques are described

Angle resolved photoelectron spectroscopy of two-color XUV-NIR ionization with polarization control

Electron emission caused by extreme ultraviolet (XUV) radiation in the presence of a strong near infrared (NIR) field leads to multiphoton interactions that depend on several parameters. Here, a comprehensive study of the influence of the angle between the polarization directions of the NIR and XUV fields on the two-color angle-resolved photoelectron spectra of He and Ne is presented. The resulting photoelectron angular distribution strongly depends on the orientation of the NIR polarization plane with respect to that of the XUV field. The prevailing influence of the intense NIR field over the angular emission characteristics for He(1s) and Ne(2p) ionization lines is shown. The underlying processes are modeled in the frame of the strong field approximation (SFA) which shows very consistent agreement with the experiment reaffirming the power of the SFA for multicolor-multiphoton ionization in this regime

Coronacrisis: threats and opportunities for the financial market

The results of a scientific study of various areas of the financial market (such as credit market, insurance market, investment market, currency market, stocks and bonds market), aimed at studying the potential opportunities and threats from a pandemic COVID-19 are presented. In the work qualitative analysis of financial events in 2020 were used, the opinions of experts were analyzed, and statistical data was interpreted. Main conclusion: there is a reduction in production activity around the world which caused a decline in oil prices, led to a sharp decline in stock prices in major markets and the fact that bond yields began to decrease

Emulsion sheet doublets as interface trackers for the OPERA experiment

New methods for efficient and unambiguous interconnection between electronic counters and target units based on nuclear photographic emulsion films have been developed. The application to the OPERA experiment, that aims at detecting oscillations between mu neutrino and tau neutrino in the CNGS neutrino beam, is reported in this paper. In order to reduce background due to latent tracks collected before installation in the detector, on-site large-scale treatments of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd) packages, each made of a doublet of emulsion films, have been designed, assembled and coupled to the OPERA target units ("ECC bricks"). A device has been built to print X-ray spots for accurate interconnection both within the CSd and between the CSd and the related ECC brick. Sample emulsion films have been extensively scanned with state-of-the-art automated optical microscopes. Efficient track-matching and powerful background rejection have been achieved in tests with electronically tagged penetrating muons. Further improvement of in-doublet film alignment was obtained by matching the pattern of low-energy electron tracks. The commissioning of the overall OPERA alignment procedure is in progress.Comment: 19 pages, 19 figure

First events from the CNGS neutrino beam detected in the OPERA experiment

The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in appearance mode, through the study of nu_mu to nu_tau oscillations. The apparatus consists of a lead/emulsion-film target complemented by electronic detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam (CNGS) 730 km away from the neutrino source. In August 2006 a first run with CNGS neutrinos was successfully conducted. A first sample of neutrino events was collected, statistically consistent with the integrated beam intensity. After a brief description of the beam and of the various sub-detectors, we report on the achievement of this milestone, presenting the first data and some analysis results.Comment: Submitted to the New Journal of Physic

Study of the effects induced by lead on the emulsion films of the OPERA experiment

The OPERA neutrino oscillation experiment is based on the use of the Emulsion Cloud Chamber (ECC). In the OPERA ECC, nuclear emulsion films acting as very high precision tracking detectors are interleaved with lead plates providing a massive target for neutrino interactions. We report on studies related to the effects occurring from the contact between emulsion and lead. A low radioactivity lead is required in order to minimize the number of background tracks in emulsions and to achieve the required performance in the reconstruction of neutrino events. It was observed that adding other chemical elements to the lead, in order to improve the mechanical properties, may significantly increase the level of radioactivity on the emulsions. A detailed study was made in order to choose a lead alloy with good mechanical properties and an appropriate packing technique so as to have a low enough effective radioactivity.Comment: 19 pages, 11 figure

Quantum beats and fine structure in attosecond chronoscopy of strong-field photoionization of atoms

Kazansky AK, Kabachnik NM, Sazhina IP. Quantum beats and fine structure in attosecond chronoscopy of strong-field photoionization of atoms. Europhysics Letters. 2008;82(1): 13001.A theoretical model is presented which describes the time evolution of strong field photoionization as studied in recent XUV pump-IR probe attosecond tunneling (attosecond chronoscopy) experiments. The excitation of intermediate weakly bound states by an ultra-short XUV pulse (pump) is described within a sudden approximation. The photoionization of these states by a delayed strong IR pulse (probe) is described by solving the non-stationary Schrodinger equation. The results of the calculations show that the coherence of the excited states plays an important role resulting in quantum beats when the XUV pulse precedes the IR pulse. For a large overlap of the pulses a pronounced. ne structure in the cross-section is revealed. The calculations for Ne agree qualitatively with the experiment. Copyright (c) EPLA, 2008

Endothelial dysfunction and dynamics of cytokine and C-reactive protein levels in chronic heart failure patients

Vasoregulatory endothelial function and dynamics of chronic inflammatory markers were investigated in patients with chronic heart failure (CHF), receiving standard therapy including ACE inhibitors, or ACE inhibitors plus aspirin. One hundred twenty CHF patients were examined at hospitalization (first 24 hours), and 20 and 90 days later, in out-patient settings. All participants were divided into two groups - with II and III functional classes of HF, by NYHA classification. In both groups, there were patients who received aspirin plus ACE inhibitors, or ACE inhibitors only. Vasoregulatory endothelial function and dynamics of chronic inflammatory marker levels were measured in all patients. Among individuals receiving ACE inhibitors, significant decrease in inflammatory marker concentrations was observed by 90 day of the follow-up, together with clinical status improvement. In ACE inhibitors plus aspirin group, no significant decrease of these parameters was registered. Vasoregulatory endothelial function did not change in both groups. Treatment with ACE inhibitors, but not ACE inhibitors and aspirin, was associated with reduction of inflammatory marker levels and clinical status improvement