Artificially Disordered Birefringent Optical Fibers

We develop and experimentally verify a theory of evolution of polarization in artificially-disordered multi-mode optical fibers. Starting with a microscopic model of photo-induced index change, we obtain the first and second order statistics of the dielectric tensor in a Ge-doped fiber, where a volume disorder is intentionally inscribed via UV radiation transmitted through a diffuser. A hybrid coupled-power & coupled-mode theory is developed to describe the transient process of de-polarization of light launched into such a fiber. After certain characteristic distance, the power is predicted to be equally distributed over all co-propagating modes of the fiber regardless of their polarization. Polarization-resolved experiments, confirm the predicted evolution of the state of polarization. Complete mode mixing in a segment of fiber as short as ~ 10cm after 3.6dB insertion loss is experimentally observed. Equal excitation of all modes in such a multi-mode fiber creates the conditions to maximize the information capacity of the system under e.g. multiple-input-multiple-output (MIMO) transmission setup

Signals of CP Violation Beyond the MSSM in Higgs and Flavor Physics

We study an extension of the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM), considering the effects of new degrees of freedom at the TeV scale, and allowing for sources of CP violation beyond the MSSM (BMSSM). We analyze the impact of the BMSSM sources of CP violation on the Higgs collider phenomenology and on low energy flavor and CP violating observables. We identify distinct Higgs collider signatures that cannot be realized, either in the case without CP violating phases or in the CP violating MSSM, and investigate the prospects to probe them at the Tevatron and the LHC. The most striking benchmark scenario has three neutral Higgs bosons that all decay dominantly into W boson pairs and that are well within the reach of the 7 TeV LHC run. On the other hand, we also present scenarios with three Higgs bosons that have masses M_Hi > 150 GeV and decay dominantly into b bbar. Such scenarios are much more challenging to probe and can even lie completely outside the reach of the 7 TeV LHC run. We explore complementary scenarios with standard MSSM Higgs signals that allow to accommodate a sizable B_s mixing phase as indicated by D0, as well as the excess in B_s --> mu+ mu- candidates recently reported by CDF. We find that, in contrast to the MSSM, a minimal flavor violating soft sector is sufficient to generate significant corrections to CP violating observables in meson mixing, compatible with EDM constraints. In particular, a sizable B_s mixing phase, S_psiphi < 0.4, can be achieved for specific regions of parameter space. Such a large B_s mixing phase would unambiguously imply a sizable suppression of S_psiKs with respect to the SM prediction and a BR(B_s --> mu+ mu-) close to the 95% C.L. upper bound reported by CDF.Comment: 58 pages, 15 figures, 2 tables, v2 matches published versio

Magnetic structure of the swedenborgite compound CaBaMn2 Fe 2 O7 derived by powder neutron diffraction and Mössbauer spectroscopy

We present a study combining neutron diffraction and 57 Fe Mössbauer spectroscopy on a powder sample ofCaBaMn 2 Fe 2 O7 belonging to the large family of swedenborgite compounds. The undistorted hexagonal crystal structure (space group P63mc) is preserved down to low temperatures, and all employed techniques reveal a transition into a magnetically long-range ordered phase at TN = 205 K. The magnetic Bragg peak intensities from the powder diffraction patterns together with a symmetry analysis of the employed models unambiguously reveal the classical √3 × √3 magnetic structure on a hexagonal lattice with propagation vector q = ( 1/3 1/3 0). The nuclear Bragg peak intensities allowed the statistical distribution of Fe and Mn ions on both trigonal and kagome sites of the complex swedenborgite structure to be analyzed which was considered to explain the complex shape of the Mössbauer spectra

Size effects on the Neél temperature of antiferromagnetic NiO nanoparticles

Among all antiferromagnetic transition metal monoxides, NiO presents the highest Neél temperature (TN ~ 525 K). In this work, the size-dependent reduction of TN in NiO nanoparticles with average diameters (D) ranging from 4 to 9 nm is investigated by neutron diffraction. The scaling law followed by TN(D) is in agreement with the Binder theory of critical phenomena in low-dimensional systems. X-ray absorption fine structure measurements link the decrease of TN to the occurrence of size effects (average undercoordination, bond relaxation and static disorder) in the nearest and next-nearest Ni coordination shells that hold the key for the maintenance of the antiferromagnetic order

Simulation and experimental characterization of SOA-MZI-based multiwavelength conversion

We present, for the first time, extensive simulation and experimental characterizations of single SOA-MZI-based multiwavelength conversion (MWC) of NRZ data at 10 Gb/s and RZ data at 40 Gb/s under various parametric conditions deploying ITU standard 100- and 200-GHz channel spacing. We analyze, in particular, the physical performance impairments caused by high-order four-wave mixing interference. Our simulation results indicate the promising performance of the MWC up to eight channels with 200-GHz channel spacing. We further experimentally demonstrate four-channel 10-Gb/s error-free MWC with signal regeneration possibilities and 40-Gb/s MWC with moderate penalties, based on commercially available integrated SOA-MZIs. We obtained clear, open converted eye diagrams and achieved negligible difference in channel performance among all MWC channels at both bit rates. Our results proved the excellent performance of a simple scheme for various future network and system applications, such as all-optical wavelength multicast and grid networking

Circulating vitamin D levels and colorectal cancer risk: a meta-analysis and systematic review of case-control and prospective cohort studies

The associations between circulating vitamin D concentrations and total and site-specific colorectal cancer (CRC) incidence have been examined in several epidemiological studies with overall inconclusive findings. The aim of this systematic review and meta-analysis of both case-control and prospective cohort studies was to evaluate the association between CRC and circulating levels of vitamin D. The main exposure and outcome were circulating total 25(OH)D and CRC, respectively, in the overall population (i.e., all subjects). Two reviewers, working independently, screened all the literature available to identify studies that met the inclusion criteria (e.g., case-control or prospective cohort studies, published in English, and excluding non-original papers). Data were pooled by the generic inverse variance method using a random or fixed effect model, as approriate. Heterogeneity was identified using the Cochran's Q-test and quantified by the I2 statistic. Results were stratified by study design, sex, and metabolite of vitamin D. Sensitivity and subgroup analyses were also performed. A total of 28 original studies were included for the quantitative meta-analysis. Meta-analyses comparing the highest vs lowest categories, showed a 39% lower risk between levels of total 25(OH)D and CRC risk (OR (95% CI): 0.61 (0.52; 0.71); 11 studies) in case-control studies; whereas a 20% reduced CRC risk in prospective cohort studies (HR (95% CI): 0.80 (0.66; 0.97); 6 studies). Results in women mirrored main results, whereas results in men were non-significant in both analyses. Our findings support an inverse association between circulating vitamin D levels and CRC risk

Three strongly correlated charged bosons in a one-dimensional harmonic trap: natural orbital occupancies

We study a one-dimensional system composed of three charged bosons confined in an external harmonic potential. More precisely, we investigate the ground-state correlation properties of the system, paying particular attention to the strong-interaction limit. We explain for the first time the nature of the degeneracies appearing in this limit in the spectrum of the reduced density matrix. An explicit representation of the asymptotic natural orbitals and their occupancies is given in terms of some integral equations.Comment: 6 pages, 4 figures, To appear in European Physical Journal

Glycaemic Control with Insulin Glargine 300 U/mL in Individuals with Type 2 Diabetes and Chronic Kidney Disease : A REALI European Pooled Data Analysis

Altres ajuts: Sanofi (Paris, France)Introduction: Management of type 2 diabetes mellitus (T2DM) in patients with chronic kidney disease is complex. Using the REALI European pooled database, we determined the impact of baseline renal function on the effectiveness and safety of insulin glargine 300 U/mL (Gla-300) initiated in adults with inadequately controlled T2DM. Methods: Data from 1712 patients with available estimated glomerular filtration rate (eGFR) at baseline were pooled from six 24-week prospective studies. Patients who received once-daily subcutaneous injections of Gla-300 were classified into four renal function subgroups, according to baseline eGFR: ≥ 90 (N = 599), 60-89 (N = 786), 45-59 (N = 219), and 15-44 mL/min/1.73 m (N = 108). Results: Compared to those with baseline eGFR ≥ 60 mL/min/1.73 m, patients with lower eGFR values tended to be older, had a longer T2DM duration, and were more likely to present diabetic complications. After 24 weeks of Gla-300 therapy, the least-squares mean (95% confidence interval) decrease in haemoglobin A1c (HbA1c) from baseline (− 1.14% [− 1.28 to − 1.00], − 1.21% [− 1.34 to − 1.08], − 1.19% [− 1.36 to − 1.01], and − 0.99% [− 1.22 to − 0.76]) and the proportion of patients achieving HbA1c < 7.5% (53.3%, 51.3%, 49.5%, and 51.5%) were comparable in the ≥ 90, 60-89, 45-59, and 15-44 mL/min/1.73 m subgroups, respectively. Although the incidence of hypoglycaemia was overall low, more patients in the eGFR 15-44 mL/min/1.73 m subgroup experienced hypoglycaemia at night or at any time of the day compared with higher eGFR subgroups. There were no notable differences between the renal function subgroups in the changes in Gla-300 daily dose and body weight from baseline to week 24. Conclusion: Although an eGFR of 15-44 mL/min/1.73 m was associated with a slightly increased risk of hypoglycaemia among patients with inadequately controlled T2DM, Gla-300 provided glycaemic improvement with an overall favourable safety profile regardless of baseline eGFR

Rationale and methodology for a European pooled analysis of postmarketing interventional and observational studies of insulin glargine 300 U/mL in diabetes: protocol of REALI project

INTRODUCTION: Type 2 diabetes mellitus (T2DM) is a common and heterogeneous disease. Using advanced analytic approaches to explore real-world data may identify different disease characteristics, responses to treatment and progression patterns. Insulin glargine 300 units/mL (Gla-300) is a second-generation basal insulin analogue with preserved glucose-lowering efficacy but reduced risk of hypoglycaemia. The purpose of the REALI pooled analysis described in this paper is to advance the understanding of the effectiveness and real-world safety of Gla-300 based on a large European patient database of postmarketing interventional and observational studies. METHODS AND ANALYSIS: In the current round of pooling, REALI will include data from up to 10 000 subjects with diabetes mellitus (mostly T2DM) from 20 European countries. Outcomes of interest include change from baseline to week 24 in haemoglobin A1c, fasting plasma glucose, self-measured plasma glucose, body weight, insulin dose, incidence and rate of any-time-of-the-day and nocturnal hypoglycaemia. The data pool is being investigated using two complementary methodologies: a conventional descriptive, univariate and multivariable prognostic analysis; and a data-mining approach using subgroup discovery to identify phenotypic clusters of patients who are highly associated with the outcome of interest. By mid-2019, deidentified data of 7584 patients were included in the REALI database, with a further expected increase in patient number in 2020 as a result of pooling additional studies. ETHICS AND DISSEMINATION: The proposed study does not involve collection of primary data. Moreover, all individual study protocols were approved by independent local ethics committees, and all study participants provided written informed consent. Furthermore, patient data is deidentified before inclusion in the REALI database. Hence, there is no requirement for ethical approval. Results will be disseminated via peer-reviewed publications and presentations at international congresses as data are analysed