Structural Modifications of the Brain in Acclimatization to High-Altitude

Adaptive changes in respiratory and cardiovascular responses at high altitude (HA) have been well clarified. However, the central mechanisms underlying HA acclimatization remain unclear. Using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) with fractional anisotropy (FA) calculation, we investigated 28 Han immigrant residents (17–22 yr) born and raised at HA of 2616–4200 m in Qinghai-Tibetan Plateau for at least 17 years and who currently attended college at sea-level (SL). Their family migrated from SL to HA 2–3 generations ago and has resided at HA ever since. Control subjects were matched SL residents. HA residents (vs. SL) showed decreased grey matter volume in the bilateral anterior insula, right anterior cingulate cortex, bilateral prefrontal cortex, left precentral cortex, and right lingual cortex. HA residents (vs. SL) had significantly higher FA mainly in the bilateral anterior limb of internal capsule, bilateral superior and inferior longitudinal fasciculus, corpus callosum, bilateral superior corona radiata, bilateral anterior external capsule, right posterior cingulum, and right corticospinal tract. Higher FA values in those regions were associated with decreased or unchanged radial diffusivity coinciding with no change of longitudinal diffusivity in HA vs. SL group. Conversely, HA residents had lower FA in the left optic radiation and left superior longitudinal fasciculus. Our data demonstrates that HA acclimatization is associated with brain structural modifications, including the loss of regional cortical grey matter accompanied by changes in the white matter, which may underlie the physiological adaptation of residents at HA

The expansion field: The value of H_0

Any calibration of the present value of the Hubble constant requires recession velocities and distances of galaxies. While the conversion of observed velocities into true recession velocities has only a small effect on the result, the derivation of unbiased distances which rest on a solid zero point and cover a useful range of about 4-30 Mpc is crucial. A list of 279 such galaxy distances within v<2000 km/s is given which are derived from the tip of the red-giant branch (TRGB), from Cepheids, and from supernovae of type Ia (SNe Ia). Their random errors are not more than 0.15 mag as shown by intercomparison. They trace a linear expansion field within narrow margins from v=250 to at least 2000 km/s. Additional 62 distant SNe Ia confirm the linearity to at least 20,000 km/s. The dispersion about the Hubble line is dominated by random peculiar velocities, amounting locally to <100 km/s but increasing outwards. Due to the linearity of the expansion field the Hubble constant H_0 can be found at any distance >4.5 Mpc. RR Lyr star-calibrated TRGB distances of 78 galaxies above this limit give H_0=63.0+/-1.6 at an effective distance of 6 Mpc. They compensate the effect of peculiar motions by their large number. Support for this result comes from 28 independently calibrated Cepheids that give H_0=63.4+/-1.7 at 15 Mpc. This agrees also with the large-scale value of H_0=61.2+/-0.5 from the distant, Cepheid-calibrated SNe Ia. A mean value of H_0=62.3+/-1.3 is adopted. Because the value depends on two independent zero points of the distance scale its systematic error is estimated to be 6%. Typical errors of H_0 come from the use of a universal, yet unjustified P-L relation of Cepheids, the neglect of selection bias in magnitude-limited samples, or they are inherent to the adopted models.Comment: 44 pages, 4 figures, 6 tables, accepted for publication in the Astronony and Astrophysics Review 15

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

A search is performed for heavy long-lived charged particles using 3.0 fb$^{-1}$ of pp collisions collected at $\sqrt{s}$= 7 and 8 TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkovdetectors to distinguish the heavy, slow-moving particles from muons. No evidence is found for the production of such long-lived states. The results are expressed as limits on the Drell-Yan production of pairs of long-lived particles, with both particles in the LHCb pseudorapidity acceptance, $1.8 < \eta < 4.9$. The mass-dependent cross-section upper limits are in the range 2-4 fb (at 95\% CL) for masses between 124 and 309 GeV/c$^2$

Microbial Symbionts of Antarctic Marine Benthic Invertebrates

The microbial colonization of living surfaces may be affected by several environmental and biological factors and may play an important role in the development and evolution of the holobiont. Antarctica, as an extreme and isolated environment, offers a unique opportunity to study the peculiar and often strict interactions that are established between a benthic host and its symbionts. Despite this, to date the association between microbes and Antarctic benthic invertebrates has been only seldom investigated, resulting in fragmented and poor information. This chapter will be devoted to showcase our current knowledge on prokaryotic (Bacteria and Archaea) and eukaryotic (yeasts and diatoms) microbial symbionts of Antarctic benthic invertebrate hosts, including mainly Porifera and, at to a lesser extent, Cnidaria, Echinodermata and Annelida