Understanding the importance of selenium and selenoproteins in muscle function

Selenium is an essential trace element. In cattle, selenium deficiency causes dysfunction of various organs, including skeletal and cardiac muscles. In humans as well, lack of selenium is associated with many disorders, but despite accumulation of clinical reports, muscle diseases are not generally considered on the list. The goal of this review is to establish the connection between clinical observations and the most recent advances obtained in selenium biology. Recent results about a possible role of selenium-containing proteins in muscle formation and repair have been collected. Selenoprotein N is the first selenoprotein linked to genetic disorders consisting of different forms of congenital muscular dystrophies. Understanding the muscle disorders associated with selenium deficiency or selenoprotein N dysfunction is an essential step in defining the causes of the disease and obtaining a better comprehension of the mechanisms involved in muscle formation and maintenance

The Arctic plant aboveground biomass synthesis dataset

Abstract Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomass in these northern ecosystems. Here, we present The Arctic plant aboveground biomass synthesis dataset, which includes field measurements of lichen, bryophyte, herb, shrub, and/or tree aboveground biomass (g m−2) on 2,327 sample plots from 636 field sites in seven countries. We created the synthesis dataset by assembling and harmonizing 32 individual datasets. Aboveground biomass was primarily quantified by harvesting sample plots during mid- to late-summer, though tree and often tall shrub biomass were quantified using surveys and allometric models. Each biomass measurement is associated with metadata including sample date, location, method, data source, and other information. This unique dataset can be leveraged to monitor, map, and model plant biomass across the rapidly warming Arctic

Shape Abnormalities of the Caudate Nucleus Correlate with Poorer Gait and Balance:Results from a Subset of the LADIS Study

OBJECTIVE: Functional deficits seen in several neurodegenerative disorders have been linked with dysfunction in fronto-striatal circuits and with associated shape alterations in striatal structures. The severity of visible white matter changes (WMC) on MRI has been found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction. METHOD: MRI scans and clinical gait/balance data (scores from the SPPB - Short Physical Performance Battery) were sourced from 66 subjects in the previously-published LADIS trial, which was performed in >65 y.o. non-disabled individuals with WMC at study entry. Data were obtained at study entry and at three-year follow-up. Caudate nuclei and putamina were manually traced using a previously published method, and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis utilising the SPHARM toolkit. RESULTS: There was no correlation between the severity of WMC and striatal volumes. Caudate nuclei volume correlated with performance on the SPPB at baseline, but not at follow-up, with subsequent shape analysis showing regionalisation of left caudate changes in areas corresponding to inputs of the dorsolateral prefrontal, premotor and motor cortex. There was no correlation between putamen volumes and performance on the SPPB. CONCLUSION: Disruption in frontostriatal circuits may play a role in mediating poorer physical performance in individuals with white matter changes. Striatal volume and shape changes may be suitable biomarkers for functional changes in this population

Optical monitoring of extragalactic sources for linking the ICRF and the future Gaia celestial reference frame. I. Variability of ICRF sources

Context. The astrometric mission Gaia of the European Space Agency is scheduled to be launched in 2013. It will provide an astrometric catalog of 500 000 extragalactic sources that could be the basis of a new optical reference frame after the Hipparcos satellite one. On the other hand, the current International Celestial Reference Frame (ICRF) is based on observations of extragalactic sources at radio wavelength. The astrometric coordinates of sources in these two reference systems will have roughly the same uncertainty. It is then mandatory to observe a set of common targets at both optical and radio wavelengths to link the ICRF with what could be called the Gaia Celestial Reference Frame (GCRF). Aims: The goal of this work is to observe a first set of 70 extragalactic sources at optical wavelengths that could achieve the link with the ICRF. Variations in the light curves of these targets are connected with astrophysical processes that could produce displacements of the optical photocenter. Such displacements, if they exist, are critical in the framework of the link of reference systems. Methods: Four telescopes were used to observe the targets at optical wavelengths. Two of them are located in France, one in Chile, and the last one in Australia. First observations were carried out during one year and a half in the R and V bands. A new method of characterizing the compactness of the targets was applied to the images obtained. Results: This paper presents results for the optical monitoring of extragalactic sources suitable for linking reference systems. We show that a large number of targets in our set are variable at the two observational wavelengths. A short presentation of each object is given, along with some references to earlier photometric studies. A morphological index is defined and applied to the 5000 images obtained during the observation campaign. Conclusions: This work fits into a more general project of astrophotometric and astrophysical studies of extragalactic radiosources in the framework of the reference systems. It brings to the astrometric community some information at optical wavelengths about a set of targets that could be used for the link between the radio ICRF and the future GCRF. Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/552/A9