Advanced cyclic accelerated aging testing of solar reflector materials

ABSTRACT: Lifetime prediction methods for the components of concentrated solar power (CSP) plants have been in the focus of interest of manufacturers and plant developers for the past years. Recently, an accelerated aging standard for solar mirrors was published by the Spanish AENOR committee [1]. This standard allows performing comparative testing but it is not suited to derive meaningful life-time estimations. Firstly, the testing defined in the standard is not aggressive enough to produce significant degradation on most of the materials and secondly, it has been shown that the passing of these tests does not guarantee a high durability during outdoor exposure [2]. These findings have proven the need for the investigation of more realistic procedures. To provoke the mechanisms that are detected during outdoor exposure, a more realistic application of environmental stresses is being investigated. In this work a series of tests is conducted in which several weathering stresses are combined and applied in a cyclic manner. Some of these cycles have shown to correlate better with real outdoor behavior.N/

Supra and intracondylar open fracture of the femur in a motocross athlete: case report

The authors report the case of a patient (amateur motocross competitor) who suffered a fall during a motocross competition resulting in a supra and intracondylar open fracture in the right femur.Os autores apresentam o relato de um caso de uma paciente (atleta amador de motocross) que sofreu uma queda durante uma competição e teve fratura supra e intracondiliana exposta de fêmur direito.Universidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e Traumatologia Centro de Traumatologia do EsporteHospital e Maternidade Assunção Departamento de Ortopedia e TraumatologiaUNIFESP, Depto. de Ortopedia e Traumatologia Centro de Traumatologia do EsporteSciEL

Managing and exploiting stress in the antibody factory

Like us, our cells have evolved strategies to cope with, and sometimes utilize, stress. Molecular analyses of plasma cell biogenesis, lifestyle and death suggest that protein synthesis‐dependent stress is utilised to integrate differentiation, function and lifespan control. Plasma cells are short‐lived professional secretory cells, each of them capable of releasing several thousands antibodies per second. Their differentiation from B lymphocytes entails the spectacular enlargement of the endoplasmic reticulum (ER), finalized to sustain massive Ig production. Nonetheless, symptoms of ER stress are evident, and the UPR‐related transcription factor XBP‐1 is essential for differentiation. Surprisingly, the development of such an efficient factory is matched by a decrease in proteasomes. The unbalanced load/capacity ratio leads to accumulation of polyubiquitinated molecules and predisposes plasma cells to apoptosis. Exuberant antibody secretion imposes considerable stress on metabolic and redox homeostasis. Collectively, these stressful conditions may link plasma cell death to antibody production, providing a molecular counter for secreted molecules, as well as an explanation for the peculiar sensitivity of myeloma cells towards proteasome inhibitors

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum