2,637 research outputs found
CPT and Lorentz-invariance violation
The largest gap in our understanding of nature at the fundamental level is
perhaps a unified description of gravity and quantum theory. Although there are
currently a variety of theoretical approaches to this question, experimental
research in this field is inhibited by the expected Planck-scale suppression of
quantum-gravity effects. However, the breakdown of spacetime symmetries has
recently been identified as a promising signal in this context: a number of
models for underlying physics can accommodate minuscule Lorentz and CPT
violation, and such effects are amenable to ultrahigh-precision tests. This
presentation will give an overview of the subject. Topics such as motivations,
the SME test framework, mechanisms for relativity breakdown, and experimental
tests will be reviewed. Emphasis is given to observations involving antimatter.Comment: 6 page
DevOps and its Philosophy : Education Matters!
DevOps processes comply with principles and offer practices with main objective to support efficiently the evolution of IT systems. To be efficient a DevOps process relies on a set of integrated tools. DevOps is among the first competencies together with Agile method required by the industry. As a new approach it is necessary to develop and offer to the academy and to the industry training programs to prepare our engineers in the best possible way.
In this chapter we present the main aspects of the educational effort made in the recent years to educate to the concepts and values of the DevOps philosophy. This includes principles, practices, tools and architectures, primarily the microservices architectural style, which shares many aspects of DevOps approaches especially the modularity and flexibility which enables continuous change and delivery. Two experiences have been made, one at academic level as a master program course and the other, as an industrial training.
Based on those two experiences, we provide a comparative analysis and some proposals in order to develop and improve DevOps education for the future
AzTEC 1.1 mm Observations of the MBM12 Molecular Cloud
We present 1.1 mm observations of the dust continuum emission from the MBM12
high-latitude molecular cloud observed with the Astronomical Thermal Emission
Camera (AzTEC) mounted on the James Clerk Maxwell Telescope on Mauna Kea,
Hawaii. We surveyed a 6.34 deg centered on MBM12, making this the largest
area that has ever been surveyed in this region with submillimeter and
millimeter telescopes. Eight secure individual sources were detected with a
signal-to-noise ratio of over 4.4. These eight AzTEC sources can be considered
to be real astronomical objects compared to the other candidates based on
calculations of the false detection rate. The distribution of the detected 1.1
mm sources or compact 1.1 mm peaks is spatially anti-correlated with that of
the 100 micronm emission and the CO emission. We detected the 1.1 mm
dust continuum emitting sources associated with two classical T Tauri stars,
LkHalpha262 and LkHalpha264. Observations of spectral energy distributions
(SEDs) indicate that LkHalpha262 is likely to be Class II (pre-main-sequence
star), but there are also indications that it could be a late Class I
(protostar). A flared disk and a bipolar cavity in the models of Class I
sources lead to more complicated SEDs. From the present AzTEC observations of
the MBM12 region, it appears that other sources detected with AzTEC are likely
to be extragalactic and located behind MBM12. Some of these have radio
counterparts and their star formation rates are derived from a fit of the SEDs
to the photometric evolution of galaxies in which the effects of a dusty
interstellar medium have been included.Comment: 8 pages, 6 figures, The Astrophysical Journal, in pres
Ground beetle assemblages in Beijing’s new mountain forests
Mature forests have been almost completely destroyed in China’s northern regions, but this has been followed by large-scale reforestation in the wake of environmental degradation. Although future forest plantations are expected to expand over millions of hectares, knowledge about the ecology and biodiversity of China’s replanted forests remains very limited. Addressing these knowledge gaps, we recorded ground beetle (Coleoptera: Carabidae) communities in five secondary forest types: plantations of Chinese Pine (Pinus tabulaeformis) and Prince Rupprecht’s Larch (Larix principis-rupprechtii), Oak (Quercus wutaishanica) and Asian White Birch (Betula platyphylla) woodlands, and naturally regenerated mixed forest. Species richness peaked in mixed forests, while pine and oak woodlands harboured discrete communities of intermediate species richness. Oak, pine and mixed forest habitats also showed high levels of species turnover between plots. Canopy closure was an important factor influencing ground beetle assemblages and diversity, and a number of forest specialist species only occurred in pine or oak forests. We believe that some forest specialists have survived earlier deforestation and appear to be supported by new plantation forests, but maintenance of secondary native oak and mixed forests is crucial to safeguard the overall species pool
Gravitational physics with antimatter
The production of low-energy antimatter provides unique opportunities to
search for new physics in an unexplored regime. Testing gravitational
interactions with antimatter is one such opportunity. Here a scenario based on
Lorentz and CPT violation in the Standard- Model Extension is considered in
which anomalous gravitational effects in antimatter could arise.Comment: 5 pages, presented at the International Conference on Exotic Atoms
(EXA 2008) and the 9th International Conference on Low Energy Antiproton
Physics (LEAP 2008), Vienna, Austria, September 200
Dietary Supplementation with Soluble Plantain Non-Starch Polysaccharides Inhibits Intestinal Invasion of Salmonella Typhimurium in the Chicken
Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1–99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5–10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64–81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75–90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis
Decoupling of diffusion from structural relaxation and spatial heterogeneity in a supercooled simple liquid
We report a molecular dynamics simulation of a supercooled simple monatomic
glass-forming liquid. It is found that the onset of the supercooled regime
results in formation of distinct domains of slow diffusion which are confined
to the long-lived icosahedrally structured clusters associated with deeper
minima in the energy landscape. As these domains, possessing a low-dimensional
geometry, grow with cooling and percolate below , the critical temperature
of the mode coupling theory, a sharp slowing down of the structural relaxation
relative to diffusion is observed. It is concluded that this latter anomaly
cannot be accounted for by the spatial variation in atomic mobility; instead,
we explain it as a direct result of the configuration-space constraints imposed
by the transient structural correlations. We also conjecture that the observed
tendency for low-dimensional clustering may be regarded as a possible mechanism
of fragility.Comment: To be published in PR
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