University of Geneva

About: University of Geneva is a education organization based out in Geneva, Switzerland. It is known for research contribution in the topics: Population & Galaxy. The organization has 26887 authors who have published 65265 publications receiving 2931373 citations. The organization is also known as: Geneva University & Universite de Geneve.

Planck 2015 results - XVII. Constraints on primordial non-Gaussianity

Abstract: The Planck full mission cosmic microwave background (CMB) temperature and E-mode polarization maps are analysed to obtain constraints on primordial non-Gaussianity (NG). Using three classes of optimal bispectrum estimators – separable template-fitting (KSW), binned, and modal – we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result from temperature alone ƒlocalNL = 2.5 ± 5.7, ƒequilNL= -16 ± 70, , and ƒorthoNL = -34 ± 32 (68% CL, statistical). Combining temperature and polarization data we obtain ƒlocalNL = 0.8 ± 5.0, ƒequilNL= -4 ± 43, and ƒorthoNL = -26 ± 21 (68% CL, statistical). The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are consistent with estimators based on measuring the Minkowski functionals of the CMB. The effect of time-domain de-glitching systematics on the bispectrum is negligible. In spite of these test outcomes we conservatively label the results including polarization data as preliminary, owing to a known mismatch of the noise model in simulations and the data. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and derive constraints on early universe scenarios that generate primordial NG, including general single-field models of inflation, axion inflation, initial state modifications, models producing parity-violating tensor bispectra, and directionally dependent vector models. We present a wide survey of scale-dependent feature and resonance models, accounting for the “look elsewhere” effect in estimating the statistical significance of features. We also look for isocurvature NG, and find no signal, but we obtain constraints that improve significantly with the inclusion of polarization. The primordial trispectrum amplitude in the local model is constrained to be

Methicillin-resistant Staphylococcus aureus.

Abstract: Since the 1960s, methicillin-resistant Staphylococcus aureus (MRSA) has emerged, disseminated globally and become a leading cause of bacterial infections in both health-care and community settings. However, there is marked geographical variation in MRSA burden owing to several factors, including differences in local infection control practices and pathogen-specific characteristics of the circulating clones. Different MRSA clones have resulted from the independent acquisition of staphylococcal cassette chromosome mec (SCCmec), which contains genes encoding proteins that render the bacterium resistant to most β-lactam antibiotics (such as methicillin), by several S. aureus clones. The success of MRSA is a consequence of the extensive arsenal of virulence factors produced by S. aureus combined with β-lactam resistance and, for most clones, resistance to other antibiotic classes. Clinical manifestations of MRSA range from asymptomatic colonization of the nasal mucosa to mild skin and soft tissue infections to fulminant invasive disease with high mortality. Although treatment options for MRSA are limited, several new antimicrobials are under development. An understanding of colonization dynamics, routes of transmission, risk factors for progression to infection and conditions that promote the emergence of resistance will enable optimization of strategies to effectively control MRSA. Vaccine candidates are also under development and could become an effective prevention measure.

A reversible form of axon damage in experimental autoimmune encephalomyelitis and multiple sclerosis

Abstract: In multiple sclerosis, a common inflammatory disease of the central nervous system, immune-mediated axon damage is responsible for permanent neurological deficits. How axon damage is initiated is not known. Here we use in vivo imaging to identify a previously undescribed variant of axon damage in a mouse model of multiple sclerosis. This process, termed 'focal axonal degeneration' (FAD), is characterized by sequential stages, beginning with focal swellings and progressing to axon fragmentation. Notably, most swollen axons persist unchanged for several days, and some recover spontaneously. Early stages of FAD can be observed in axons with intact myelin sheaths. Thus, contrary to the classical view, demyelination-a hallmark of multiple sclerosis-is not a prerequisite for axon damage. Instead, focal intra-axonal mitochondrial pathology is the earliest ultrastructural sign of damage, and it precedes changes in axon morphology. Molecular imaging and pharmacological experiments show that macrophage-derived reactive oxygen and nitrogen species (ROS and RNS) can trigger mitochondrial pathology and initiate FAD. Indeed, neutralization of ROS and RNS rescues axons that have already entered the degenerative process. Finally, axonal changes consistent with FAD can be detected in acute human multiple sclerosis lesions. In summary, our data suggest that inflammatory axon damage might be spontaneously reversible and thus a potential target for therapy.