Lactate, N-acetylaspartate, choline and creatine concentrations, and spin-spin relaxation in thalamic and occipito-parietal regions of developing human brain

Previous studies of the brains of normal infants demonstrated lower lactate (Lac)/choline (Cho), Lac/creatine (Cr), and Lac/ N-acetylaspartate (Naa) peak-area ratios in the thalamic region (predominantly gray matter) compared with occipitoparietal (mainly unmyelinated white matter) values. In the present study, thalamic Cho, Cr, and Naa concentrations between 32-42 weeks\u27 gestational plus postnatal age were greater than occipito-parietal: 4.6 +/- 0.8 (mean +/- SE), 10.5 +/- 2.0, and 9.0 +/- 0.7 versus 1.8 +/- 0.6, 5.8 +/- 1.5, and 3.4 +/- 1.1 mmol/kg wet weight, respectively: Lac concentrations were similar, 2.7 +/- 0.6 and 3.3 +/- 1.3 mmol/kg wet weight, respectively. In the thalamic region, Cho and Naa T2s increased, and Cho and Lac concentrations decreased, during development. Lower thalamic Lac peak-area ratios are principally due to higher thalamic concentrations of Cho, Cr, and Naa rather than less Lac. The high thalamic Cho concentration may relate to active myelination; the high thalamic Naa concentration may be due to advanced gray-matter development including active myelination. Lac concentration is higher in neonatal than in adult brain

Anyonic behavior of quantum group gases

We first introduce and discuss the formalism of $SU_q(N)$-bosons and fermions and consider the simplest Hamiltonian involving these operators. We then calculate the grand partition function for these models and study the high temperature (low density) case of the corresponding gases for $N=2$. We show that quantum group gases exhibit anyonic behavior in $D=2$ and $D=3$ spatial dimensions. In particular, for a $SU_q(2)$ boson gas at $D=2$ the parameter $q$ interpolates within a wider range of attractive and repulsive systems than the anyon statistical parameter.Comment: LaTeX file, 19 pages, two figures ,uses epsf.st

A Concept for a Mars Boundary Layer Sounding Balloon: Science Case, Technical Concept and Deployment Risk Analysis

The Mars Exploration Program Analysis Group has identified measurements of the state and the variability of the Martian atmosphere as high priority investigations for the upcoming years. Balloon-borne instruments could bridge the gap in both temporal and spatial resolution in mesoscale distances between local, stationary landers and global orbiter observations. The idea to use a balloon system for such a purpose is not new in essence and has been proposed already in past decades. While those concepts considered an aerial deployment during entry and descent, the concept outlined in this study revisits a launch off the payload deck of a lander from the Martian surface. This deployment option profits today mainly from the technological advance in micro-electronics and sensor miniaturization, which enables the design of a balloon-probe significantly smaller than earlier proposed systems. This paper presents the feasibility assessment for this instrument and gives further details on the scientific and operational concept, a strawman sensor suite, its system components and the associated size and budget estimates. It is complemented by the analysis scheme proposed to assess, manage and mitigate the deployment risk involved in automatically launching such a balloon-system off a planetary surface

Social Interactions vs Revisions, What is important for Promotion in Wikipedia?

In epistemic community, people are said to be selected on their knowledge contribution to the project (articles, codes, etc.) However, the socialization process is an important factor for inclusion, sustainability as a contributor, and promotion. Finally, what does matter to be promoted? being a good contributor? being a good animator? knowing the boss? We explore this question looking at the process of election for administrator in the English Wikipedia community. We modeled the candidates according to their revisions and/or social attributes. These attributes are used to construct a predictive model of promotion success, based on the candidates's past behavior, computed thanks to a random forest algorithm. Our model combining knowledge contribution variables and social networking variables successfully explain 78% of the results which is better than the former models. It also helps to refine the criterion for election. If the number of knowledge contributions is the most important element, social interactions come close second to explain the election. But being connected with the future peers (the admins) can make the difference between success and failure, making this epistemic community a very social community too

Carrier-envelope phase dependent high-order harmonic generation with a high-repetition rate OPCPA-system

We study high-order harmonic generation with a high-repetition rate (200 kHz), few-cycle, driving laser, based on optical parametric chirped pulse amplification. The system delivers carrier-envelope phase stable, 8 fs, 10 μJ pulses at a central wavelength of 890 nm. High-order harmonics, generated in a high-pressure Ar gas jet, exhibit a strong CEP-dependence over a large spectral range owing to excellent stability of the driving laser pulses. This range can be divided into three spectral regions with distinct CEP influence. The observed spectral interference structures are explained by an analytical model based upon multiple pulse interferences.Marie Curie Research Training Network ATTOFELEuropean Research CouncilKnut and Alice Wallenberg foundationSwedish Foundation for Strategic ResearchSwedish Research Counci

Relativistic quantum clocks

The conflict between quantum theory and the theory of relativity is exemplified in their treatment of time. We examine the ways in which their conceptions differ, and describe a semiclassical clock model combining elements of both theories. The results obtained with this clock model in flat spacetime are reviewed, and the problem of generalizing the model to curved spacetime is discussed, before briefly describing an experimental setup which could be used to test of the model. Taking an operationalist view, where time is that which is measured by a clock, we discuss the conclusions that can be drawn from these results, and what clues they contain for a full quantum relativistic theory of time.Comment: 12 pages, 4 figures. Invited contribution for the proceedings for "Workshop on Time in Physics" Zurich 201

One dimensional potentials in q space

We study the one dimensional potentials in q space and the new features that arise. In particular we show that the probability of tunneling of a particle through a barrier or potential step is less than the one of the same particle with the same energy in ordinary space which is somehow unexpected. We also show that the tunneling time for a particle in q space is less than the one of the same particle in ordinary space.Comment: 10 pages, LaTeX2e, no figur