Prevalence and Characterization of Mild Cognitive Impairment in Retired National Football League Players

It has been hypothesized that exposure to repetitive head trauma from contact sports over a long-playing career may eventuate in an increased risk of late-life cognitive impairment. There are currently two competing hypotheses about the possible mechanism underlying such impairment. One is the presence of a unique neurodegenerative disorder known as (CTE). The other is diminished cerebral reserve leading to the earlier clinical expression of age-related neurodegenerative diseases such as mild cognitive impairment (MCI) and Alzheimer's disease (AD). The present study examined informant AD8 inventory data in a sample of 513 retired National Football League (NFL) players. These data were indicative of possible cognitive impairment in 35.1% of this relatively young sample. A comparison of neurocognitive profiles in a subsample of this group to a clinical sample of patients with a diagnosis of MCI due to AD revealed a highly similar profile of impairments. Overall, the data suggest that there may be an increased prevalence of late-life cognitive impairment in retired NFL players, which may reflect diminished cerebral reserve. The findings are considered preliminary, but emphasize the need for larger, controlled studies on this issue. (JINS, 2013, 19, 1–8

VUV and X-ray coherent light with tunable polarization from single-pass free-electron lasers

Tunable polarization over a wide spectral range is a required feature of light sources employed to investigate the properties of local symmetry in both condensed and low-density matter. Among new-generation sources, free-electron lasers possess a unique combination of very attractive features, as they allow to generate powerful and coherent ultra-short optical pulses in the VUV and X-ray spectral range. However, the question remains open about the possibility to freely vary the light polarization of a free-electron laser, when the latter is operated in the so-called nonlinear harmonic-generation regime. In such configuration, one collects the harmonics of the free-electron laser fundamental emission, gaining access to the shortest possible wavelengths the device can generate. In this letter we provide the first experimental characterization of the polarization of the harmonic light produced by a free-electron laser and we demonstrate a method to obtain tunable polarization in the VUV and X-ray spectral range. Experimental results are successfully compared to those obtained using a theoretical model based on the paraxial solution of Maxwell's equations. Our findings can be expected to have a deep impact on the design and realization of experiments requiring full control of light polarization to explore the symmetry properties of matter samples

TOP-UP OPERATIONAL EXPERIENCE AT ELETTRA

Abstract Since May 2010 Elettra, operates in top-up at both 2 and 2.4 GeV user energies. In this paper the experience during more than a year of operation in top-up is discussed and the machine up time statistics are presented and compared with the before top up period

BEAM ORBIT STABILITY AT ELETTRA

Abstract The top-up operation established since 2010 at the Elettra third-generation synchrotron light source has solved the problems related to thermal drifts and beam current dependence, and a series of feedback loops acting on the machine optics and radio-frequency systems made easier to setup and operate the ring. Those systems together with the fast orbit feedback in operation since 2007, contributed to very high electron beam orbit stability. A description of the active systems and their performance, future perspectives as well as some still open issues will be presented and discussed

COMPARISON OF TRANSVERSE SINGLE BUNCH INSTABILITIES BETWEEN THE ESRF AND ELETTRA

Abstract Transverse single bunch instabilities are measured, analysed and compared between the ESRF and ELETTRA, to obtain a deeper insight, namely how different effects influence coherent transverse motions. Despite the basic similarity of the two machines, being both examples of third generation light sources, it is found that some distinct differences in the relevant parameters such as the energy and optics, as well as the impedance, lead to the appearance of instabilities in a notably different manner. As well as summarising the results of the experiments, modelling of the broadband impedance of the two machines and comparison with expectations are presented