68 research outputs found
Multimode solutions of first-order elliptic quasilinear systems obtained from Riemann invariants
Two new approaches to solving first-order quasilinear elliptic systems of
PDEs in many dimensions are proposed. The first method is based on an analysis
of multimode solutions expressible in terms of Riemann invariants, based on
links between two techniques, that of the symmetry reduction method and of the
generalized method of characteristics. A variant of the conditional symmetry
method for constructing this type of solution is proposed. A specific feature
of that approach is an algebraic-geometric point of view, which allows the
introduction of specific first-order side conditions consistent with the
original system of PDEs, leading to a generalization of the Riemann invariant
method for solving elliptic homogeneous systems of PDEs. A further
generalization of the Riemann invariants method to the case of inhomogeneous
systems, based on the introduction of specific rotation matrices, enables us to
weaken the integrability condition. It allows us to establish a connection
between the structure of the set of integral elements and the possibility of
constructing specific classes of simple mode solutions. These theoretical
considerations are illustrated by the examples of an ideal plastic flow in its
elliptic region and a system describing a nonlinear interaction of waves and
particles. Several new classes of solutions are obtained in explicit form,
including the general integral for the latter system of equations
Hyperon production in proton-sulphur collisions at 200 GeV/c
The WA94 experiment uses the production of strange particles and antiparticles to investigate the properties of hot hadronic matter created in heavy--ion interactions. \PgL, \PagL, \PgXm\ and \PagXp\ particle yields and transverse mass spectra are presented for pS interactions. These results are compared with those from SS interactions. Our results are also compared with those from pW and SW interactions of the WA85 experiment
A study of cascade and strange baryon production in sulphur-sulphur interactions at 200 GeV/c per nucleon
Perinatal asphyxia: current status and approaches towards neuroprotective strategies, with focus on sentinel proteins
Delivery is a stressful and risky event menacing the newborn. The mother-dependent respiration has to be replaced by autonomous pulmonary breathing immediately after delivery. If delayed, it may lead to deficient oxygen supply compromising survival and development of the central nervous system. Lack of oxygen availability gives rise to depletion of NAD+ tissue stores, decrease of ATP formation, weakening of the electron transport pump and anaerobic metabolism and acidosis, leading necessarily to death if oxygenation is not promptly re-established. Re-oxygenation triggers a cascade of compensatory biochemical events to restore function, which may be accompanied by improper homeostasis and oxidative stress. Consequences may be incomplete recovery, or excess reactions that worsen the biological outcome by disturbed metabolism and/or imbalance produced by over-expression of alternative metabolic pathways. Perinatal asphyxia has been associated with severe neurological and psychiatric sequelae with delayed clinical onset. No specific treatments have yet been established. In the clinical setting, after resuscitation of an infant with birth asphyxia, the emphasis is on supportive therapy. Several interventions have been proposed to attenuate secondary neuronal injuries elicited by asphyxia, including hypothermia. Although promising, the clinical efficacy of hypothermia has not been fully demonstrated. It is evident that new approaches are warranted. The purpose of this review is to discuss the concept of sentinel proteins as targets for neuroprotection. Several sentinel proteins have been described to protect the integrity of the genome (e.g. PARP-1; XRCC1; DNA ligase IIIα; DNA polymerase β, ERCC2, DNA-dependent protein kinases). They act by eliciting metabolic cascades leading to (i) activation of cell survival and neurotrophic pathways; (ii) early and delayed programmed cell death, and (iii) promotion of cell proliferation, differentiation, neuritogenesis and synaptogenesis. It is proposed that sentinel proteins can be used as markers for characterising long-term effects of perinatal asphyxia, and as targets for novel therapeutic development and innovative strategies for neonatal care
Energy Resolution Performance of the CMS Electromagnetic Calorimeter
The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals
Molecular evolution of HIV-1 integrase during the 20 years prior to the first approval of integrase inhibitors
The neurovascular unit as a selective barrier to polymorphonuclear granulocyte (PMN) infiltration into the brain after ischemic injury
Two-Circuit System for Thermal Stabilization of Radioelectronic Facilities. Analytical Treatment
Study of the compensated lead hadron calorimeter on hadron, electron and lead-ion beams
The results of tests on a compensated lead hadron calorimeter with cell size 10*10 cm/sup 2/, thickness 8 nuclear interaction lengths and sampling of 16 mm lead, 4 mm scintillator, with hadron, electron and lead-ion beams up to 32 TeV total energy are presented. The hadronic energy resolution of the calorimeter is 57%/ square root E, the nonuniformity is better than 10% and the measured ratio e/h=1.01. Five hundred cells of this calorimeter have been made for experiments at CERN and IHEP, Protvino. (3 refs)
Radiation hardness, excess noise factor and short-term gain instability of vacuum phototriodes for the operation in pseudorapidity range 15 < eta < 30 at CMS ECAL
The operation of super radiation hard prototypes of vacuum fine-mesh phototriodes (VPT) proposed for application in CMS Endcap ECAL at the pseudorapidity of eta greater than or equivalent 2.6 has been investigated in radiation fields up to 50 kGy and neutron fluence of 7 multiplied by 10**1**5neutroncm**-**2. It is shown that anode response and the excess noise factor of VPT are independent of given above radiation dose and neutron fluence. The results of VPT gain variation measurements under rapid changes of counting rate are presented for the operation in the pseudorapidity range 1.5 less than approximately equals eta less than approximately equals 3.0
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