Quantum Gravity: General Introduction and Recent Developments

I briefly review the current status of quantum gravity. After giving some general motivations for the need of such a theory, I discuss the main approaches in quantizing general relativity: Covariant approaches (perturbation theory, effective theory, and path integrals) and canonical approaches (quantum geometrodynamics, loop quantum gravity). I then address quantum gravitational aspects of string theory. This is followed by a discussion of black holes and quantum cosmology. I end with some remarks on the observational status of quantum gravity.Comment: 21 pages, 6 figures, invited contribution for "Annalen der Physik", v2: minor corrections, additional reference

Aidnogenesis via Leptogenesis and Dark Sphalerons

We discuss aidnogenesis, the generation of a dark matter asymmetry via new sphaleron processes associated to an extra non-abelian gauge symmetry common to both the visible and the dark sectors. Such a theory can naturally produce an abundance of asymmetric dark matter which is of the same size as the lepton and baryon asymmetries, as suggested by the similar sizes of the observed baryonic and dark matter energy content, and provide a definite prediction for the mass of the dark matter particle. We discuss in detail a minimal realization in which the Standard Model is only extended by dark matter fermions which form "dark baryons" through an SU(3) interaction, and a (broken) horizontal symmetry that induces the new sphalerons. The dark matter mass is predicted to be approximately 6 GeV, close to the region favored by DAMA and CoGeNT. Furthermore, a remnant of the horizontal symmetry should be broken at a lower scale and can also explain the Tevatron dimuon anomaly.Comment: Minor changes, discussion of present constraints expanded. 16 pages, 2 eps figures, REVTeX

Associations of sitting accumulation patterns with cardio-metabolic risk biomarkers in Australian adults

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Order recall in verbal short-term memory: The role of semantic networks

In their recent article, Acheson, MacDonald, and Postle (Journal of Experimental Psychology: Learning, Memory, and Cognition 37:44-59, 2011) made an important but controversial suggestion: They hypothesized that (a) semantic information has an effect on order information in short-term memory (STM) and (b) order recall in STM is based on the level of activation of items within the relevant lexico-semantic long-term memory (LTM) network. However, verbal STM research has typically led to the conclusion that factors such as semantic category have a large effect on the number of correctly recalled items, but little or no impact on order recall (Poirier & Saint-Aubin, Quarterly Journal of Experimental Psychology 48A:384-404, 1995; Saint-Aubin, Ouellette, & Poirier, Psychonomic Bulletin & Review 12:171-177, 2005; Tse, Memory 17:874-891, 2009). Moreover, most formal models of short-term order memory currently suggest a separate mechanism for order coding-that is, one that is separate from item representation and not associated with LTM lexico-semantic networks. Both of the experiments reported here tested the predictions that we derived from Acheson et al. The findings show that, as predicted, manipulations aiming to affect the activation of item representations significantly impacted order memory

Binary and Millisecond Pulsars at the New Millennium

We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

Exploratory factor analysis of graphical features for link prediction in social networks

Social Networks attract much attention due to their ability to replicate social interactions at scale. Link prediction, or the assessment of which unconnected nodes are likely to connect in the future, is an interesting but non-trivial research area. Three approaches exist to deal with the link prediction problem: feature-based models, Bayesian probabilistic models, probabilistic relational models. In feature-based methods, graphical features are extracted and used for classification. Usually, these features are subdivided into three feature groups based on their formula. Some formulas are extracted based on neighborhood graph traverse. Accordingly, there exists three groups of features, neighborhood features, path-based features, node-based features. In this paper, we attempt to validate the underlying structure of topological features used in feature-based link prediction. The results of our analysis indicate differing results from the prevailing grouping of these features, which indicates that current literatures\u27 classification of feature groups should be redefined. Thus, the contribution of this work is exploring the factor loading of graphical features in link prediction in social networks. To the best of our knowledge, there is no prior studies had addressed it

Bioavailability in soils

The consumption of locally-produced vegetables by humans may be an important exposure pathway for soil contaminants in many urban settings and for agricultural land use. Hence, prediction of metal and metalloid uptake by vegetables from contaminated soils is an important part of the Human Health Risk Assessment procedure. The behaviour of metals (cadmium, chromium, cobalt, copper, mercury, molybdenum, nickel, lead and zinc) and metalloids (arsenic, boron and selenium) in contaminated soils depends to a large extent on the intrinsic charge, valence and speciation of the contaminant ion, and soil properties such as pH, redox status and contents of clay and/or organic matter. However, chemistry and behaviour of the contaminant in soil alone cannot predict soil-to-plant transfer. Root uptake, root selectivity, ion interactions, rhizosphere processes, leaf uptake from the atmosphere, and plant partitioning are important processes that ultimately govern the accumulation ofmetals and metalloids in edible vegetable tissues. Mechanistic models to accurately describe all these processes have not yet been developed, let alone validated under field conditions. Hence, to estimate risks by vegetable consumption, empirical models have been used to correlate concentrations of metals and metalloids in contaminated soils, soil physico-chemical characteristics, and concentrations of elements in vegetable tissues. These models should only be used within the bounds of their calibration, and often need to be re-calibrated or validated using local soil and environmental conditions on a regional or site-specific basis.Mike J. McLaughlin, Erik Smolders, Fien Degryse, and Rene Rietr

Reaction rates and transport in neutron stars

Understanding signals from neutron stars requires knowledge about the transport inside the star. We review the transport properties and the underlying reaction rates of dense hadronic and quark matter in the crust and the core of neutron stars and point out open problems and future directions.Comment: 74 pages; commissioned for the book "Physics and Astrophysics of Neutron Stars", NewCompStar COST Action MP1304; version 3: minor changes, references updated, overview graphic added in the introduction, improvements in Sec IV.A.

The expression of FHIT, PCNA and EGFR in benign and malignant breast lesions

Immunohistochemical staining for FHIT and PCNA proteins was carried out in 451 breast lesions showing nonproliferative benign breast disease (BBD) (n=263), proliferative BBD without atypia (n=128), proliferative BBD with atypia (n=11), carcinoma in situ (n=15) or invasive carcinoma (n=34) and for EGFR protein in a subset of 71 of these cases. FHIT underexpression was not detected in nonproliferative lesions, but occurred in 2% of proliferative BBD without atypia, 10% proliferative BBD with atypia, 27% of carcinoma in situ and 41% of invasive carcinoma, which suggests that it could be useful in assessing those carcinoma in situ lesions (ductal, DCIS and lobular, LCIS) that are more likely to progress to malignancy. Preliminary microarray comparisons on DCIS and invasive carcinoma samples dissected from formalin-fixed paraffin sections showed a consistent downregulation of two previously identified FHIT-related genes, caspase 1 and BRCA1 in lesions underexpressing FHIT

Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya

<p>Abstract</p> <p>Background</p> <p>The increasing number of multidrug-resistant <it>Plasmodium </it>strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from <it>Artemisia annua</it>. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine.</p> <p>Methods</p> <p><it>In vitro </it>anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive <it>Plasmodium berghei </it>NK65 strain in Swiss albino mice was used for monitoring <it>in vivo </it>activity of plant extracts.</p> <p>Results</p> <p>Chloroform extract of <it>H. antidysenterica </it>(HA-2) and petroleum ether extract of <it>V. canescens </it>(VC-1) plants significantly reduced parasitaemia in <it>P. berghei </it>infected mice. The extract HA-2 showed <it>in vitro </it>anti-plasmodial activity with its IC₅₀value 5.5 μg/ml using pLDH assay and ED₅₀value 18.29 mg/kg in <it>P. berghei </it>infected Swiss albino mice. Similarly petroleum ether extract of <it>V. canescens </it>(VC-1) showed <it>in vitro </it>anti-plasmodial activity with its IC₅₀value 2.76 μg/ml using pLDH assay and ED₅₀15.8 mg/kg in <it>P. berghei </it>infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of <it>V. canescens </it>was found slightly cytotoxic.</p> <p>Conclusion</p> <p>The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria.</p