Causal Fermion Systems and the ETH Approach to Quantum Theory

After reviewing the theory of "causal fermion systems" (CFS theory) and the "Events, Trees, and Histories Approach" to quantum theory (ETH approach), we compare some of the mathematical structures underlying these two general frameworks and discuss similarities and differences. For causal fermion systems, we introduce future algebras based on causal relations inherent to a causal fermion system. These algebras are analogous to the algebras previously introduced in the ETH approach. We then show that the spacetime points of a causal fermion system have properties similar to those of "events", as defined in the ETH approach. Our discussion is underpinned by a survey of results on causal fermion systems describing Minkowski space that show that an operator representing a spacetime point commutes with the algebra in its causal future, up to tiny corrections that depend on a regularization length

Report of the GDR working group on the R-parity violation

This report summarizes the work of the "R-parity violation group" of the French Research Network (GDR) in Supersymmetry, concerning the physics of supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron and LHC and limits on R-parity violating couplings from various processes. The report includes a discussion of the recent searches at the HERA experiment, prospects for new experiments, a review of the existing limits, and also theoretically motivated alternatives to R-parity and a brief discussion on the implications of R-parity violation on the neutrino masses.Comment: 60 pages, LaTeX, 22 figures, 2 table

New insight into zinc oxide doped with iron and its exploitation to pollutants abatement

This study aims to investigate how the photocatalytic efficiency of zinc oxide can be improved by introducing doping species into its crystal lattice. New materials based on zinc oxide doped with iron, have been synthesized using different methods, characterized and tested toward the abatement of selected organic molecules. The different synthetic strategies followed comprised sol-gel, precipitation and hydrothermal processes, in order to identify which one is capable of guaranteeing the best photocatalytic performances.The photoactivity of the new semiconductors was firstly tested using phenol as a model molecule subjected to irradiation under UV-A light. Phenol abatement is particularly favoured when using ZnO prepared via hydrothermal method and doped with iron at 0.5%. These materials were then tested toward the elimination of ketoprofen, an emerging pollutant substance, from water and real wastewater. Ketoprofen and its transformation products are completely abated within 30 min in pure water or in 1 h in wastewater

Investigation of Cu-doped ceria through a combined spectroscopic approach: Involvement of different catalytic sites in CO oxidation

Copper-ceria mixed oxides are widely considered promising catalysts for oxidation reactions, especially when the participation of lattice oxygen is required. However, the mechanistic understanding of these catalytic systems is still incomplete, due to their considerable complexity. In fact, copper doping of ceria results in the formation of a significant number of different interacting sites in continuous evolution during the catalytic processes. In the present study, pure and Cu-doped ceria samples were deeply investigated through combined spectroscopic techniques, i.e. XPS, EPR, and in situ FTIR and Raman spectroscopy. Through this systematic approach, the copper sites and lattice defects responsible for the enhanced CO oxidation activity of doped ceria were eluci-dated. Superficial Cu+ species and small Cu0 clusters promote the adsorption of CO at low temperature, while isolated Cu2+ monomers and dimers well-dispersed in the ceria matrix foster lattice oxygen mobility, involving the sub-surface in the redox phenomena. Consequently, the structure of Cu-doped ceria undergoes substantial modifications throughout CO oxidation in the absence of O2, with the formation of oxygen vacancy clusters. Anyway, these changes are reversible, and structural reorganization in the presence of O2 can occur even at room temperature. The excellent performance of Cu-doped ceria eventually stems from the effective cooperation among the different catalytic sites in the mixed oxide

ZrO2 Based materials as photocatalysts for 2-propanol oxidation by using UV and solar light irradiation and tests for CO2 reduction

Bare ZrO2, Ce doped ZrO2 and Er doped ZrO2 samples have been prepared by a hydrothermal process and have been used as photocatalysts for 2-propanol oxidation reaction in gas solid regime. Moreover, some preliminary tests have been carried out for CO2 reduction. The samples were physico-chemically characterized and both bare and doped ZrO2 based materials resulted active for oxidation and reduction reactions by using UV and solar irradiation. The reactivity results have been correlated with the compositional, structural and morphological features of the photocatalysts

Treatment of GH-deficient children with two different GH doses: effect on final height and cost-benefit implications

OBJECTIVE: Treatment of GH-deficient (GHD) children with higher doses of recombinant human GH (rhGH) than conventional ones has been reported to result in higher growth velocity and increased final height. These findings, however, were observed by comparing large but heterogeneous groups of children. We wanted to verify whether the same results could be obtained in two groups of appropriately well-matched children with isolated GHD treated with high vs conventional doses of rhGH. METHODS: Out of two cohorts of GHD children, cohort A (on a weekly rhGH dose of 0.3 mg/kg body weight) and cohort B (on a weekly rhGH dose of 0.15 mg/kg body weight), we selected two groups, each including 13 patients, who before treatment were matched for age, sex and height standard deviation score (SDS). They were followed up until final height. RESULTS: Final height SDS was significantly higher in group A (-0.45+/-0.36 (s.d.) vs -1.07+/-0.7; P=0.008), as well as height gain SDS (1.81+/-0.58 vs 1.23+/-0.62; P=0.002). The difference between final height SDS and target height SDS was positive only in group A and significantly higher in group A than in group B (0.33+/-0.51 vs -0.46+/-0.7; P=0.01). Glucose tolerance was always normal in the group treated with higher doses. CONCLUSION: The final height of children treated with higher doses of rhGH is increased, also in relation to their genetic target. The economical burden of this choice of treatment, however, has to be taken into account when evaluating the results

Insights Into the Mechanisms of Brain Endothelial Erythrophagocytosis

The endothelial cells which form the inner cellular lining of the vasculature can act as non-professional phagocytes to ingest and remove emboli and aged/injured red blood cells (RBCs) from circulation. We previously demonstrated an erythrophagocytic phenotype of the brain endothelium for oxidatively stressed RBCs with subsequent migration of iron-rich RBCs and RBC degradation products across the brain endothelium in vivo and in vitro, in the absence of brain endothelium disruption. However, the mechanisms contributing to brain endothelial erythrophagocytosis are not well defined, and herein we elucidate the cellular mechanisms underlying brain endothelial erythrophagocytosis. Murine brain microvascular endothelial cells (bEnd.3 cells) were incubated with tert-butyl hydroperoxide (tBHP, oxidative stressor to induce RBC aging in vitro)- or PBS (control)-treated mouse RBCs. tBHP increased the reactive oxygen species (ROS) formation and phosphatidylserine exposure in RBCs, which were associated with robust brain endothelial erythrophagocytosis. TNFα treatment potentiated the brain endothelial erythrophagocytosis of tBHP-RBCs in vitro. Brain endothelial erythrophagocytosis was significantly reduced by RBC phosphatidylserine cloaking with annexin-V and with RBC-ROS and phosphatidylserine reduction with vitamin C. Brain endothelial erythrophagocytosis did not alter the bEnd.3 viability, and tBHP-RBCs were localized with early and late endosomes. Brain endothelial erythrophagocytosis increased the bEnd.3 total iron pool, abluminal iron levels without causing brain endothelial monolayer disruption, and ferroportin levels. In vivo, intravenous tBHP-RBC injection in aged (17–18 months old) male C57BL/6 mice significantly increased the Prussian blue-positive iron-rich lesion load compared with PBS-RBC-injected mice. In conclusion, RBC phosphatidylserine exposure and ROS are key mediators of brain endothelial erythrophagocytosis, a process which is associated with increased abluminal iron in vitro. tBHP-RBCs result in Prussian blue-positive iron-rich lesions in vivo. Brain endothelial erythrophagocytosis may provide a new route for RBC/RBC degradation product entry into the brain to produce iron-rich cerebral microhemorrhage-like lesions