Do altmetrics promote Open Access? An exploratory analysis on altmetric differences between types of access in the field of Physics

The promotion of Open Science needs new metrics that encourage openness in scientific practices, and can help institutions to monitor it. In 2017, the European Commission (EC) created an Expert Group with the task of informing the commission on the possibility of including altmetric indicators as potential metrics that could foster and monitor open science advancements, but it failed to show how these metrics can help to foster Open Science. The current paper analyses differences in altmetric scores between Green OA publications, Gold OA publications and non OA publications. The goal of the paper is to empirically study whether altmetric indicators reinforce Open Access practices regardless of the type of access. We report a preliminary analysis based on two Physics journals. Our results show that gold OA documents are best covered in Altmetric.com and receive higher mentions than documents with other types of access. This is especially troublesome in the case of green OA, as it reflects that altmetric indicators do promote a very specific type of access closely linked with the publishing industry

Do altmetrics promote Open Access? An exploratory analysis on altmetric differences between types of access in the field of Physics

The promotion of Open Science needs new metrics that encourage openness in scientific practices, and can help institutions to monitor it. In 2017, the European Commission (EC) created an Expert Group with the task of informing the commission on the possibility of including altmetric indicators as potential metrics that could foster and monitor open science advancements, but it failed to show how these metrics can help to foster Open Science. The current paper analyses differences in altmetric scores between Green OA publications, Gold OA publications and non OA publications. The goal of the paper is to empirically study whether altmetric indicators reinforce Open Access practices regardless of the type of access. We report a preliminary analysis based on two Physics journals. Our results show that gold OA documents are best covered in Altmetric.com and receive higher mentions than documents with other types of access. This is especially troublesome in the case of green OA, as it reflects that altmetric indicators do promote a very specific type of access closely linked with the publishing industry

Grass tetany

Grass tunny is a metabolic disorder of ruminant animals that results from a deficiency of available Mg in the diet. The etiology of tetany is complicated by the many soil, plant, and animal factors that influence Mg availability to plants and in tuns to animals. This review will highlight some of these factors and provide management information which will minimize the impact of this disorder. Only the most recent and pertinent literature citations are included. A more detailed bibliographic list is available from the authors

Nuclear receptors of the honey bee: annotation and expression in the adult brain

The Drosophila genome encodes 18 canonical nuclear receptors. All of the Drosophila nuclear receptors are here shown to be present in the genome of the honey bee (Apis mellifera). Given that the time since divergence of the Drosophila and Apis lineages is measured in hundreds of millions of years, the identification of matched orthologous nuclear receptors in the two genomes reveals the fundamental set of nuclear receptors required to ‘make’ an endopterygote insect. The single novelty is the presence in the A. mellifera genome of a third insect gene similar to vertebrate photoreceptor-specific nuclear receptor (PNR). Phylogenetic analysis indicates that this novel gene, which we have named AmPNR-like, is a new member of the NR2 subfamily not found in the Drosophila or human genomes. This gene is expressed in the developing compound eye of the honey bee. Like their vertebrate counterparts, arthropod nuclear receptors play key roles in embryonic and postembryonic development. Studies in Drosophila have focused primarily on the role of these transcription factors in embryogenesis and metamorphosis. Examination of an expressed sequence tag library developed from the adult bee brain and analysis of transcript expression in brain using in situ hybridization and quantitative RT-PCR revealed that several members of the nuclear receptor family (AmSVP, AmUSP, AmERR, AmHr46, AmFtz-F1, and AmHnf-4) are expressed in the brain of the adult bee. Further analysis of the expression of AmUSP and AmSVP in the mushroom bodies, the major insect brain centre for learning and memory, revealed changes in transcript abundance and, in the case of AmUSP, changes in transcript localization, during the development of foraging behaviour in the adult. Study of the honey bee therefore provides a model for understanding nuclear receptor function in the adult brain

Asymptotic channels and gauge transformations of the time-dependent Dirac equation for extremely relativistic heavy-ion collisions

We discuss the two-center, time-dependent Dirac equation describing the dynamics of an electron during a peripheral, relativistic heavy-ion collision at extreme energies. We derive a factored form, which is exact in the high-energy limit, for the asymptotic channel solutions of the Dirac equation, and elucidate their close connection with gauge transformations which transform the dynamics into a representation in which the interaction between the electron and a distant ion is of short range. We describe the implications of this relationship for solving the time-dependent Dirac equation for extremely relativistic collisions.Comment: 12 pages, RevTeX, 2 figures, submitted to PR

The extremal limits of the C-metric: Nariai, Bertotti-Robinson and anti-Nariai C-metrics

In two previous papers we have analyzed the C-metric in a background with a cosmological constant, namely the de Sitter (dS) C-metric, and the anti-de Sitter (AdS) C-metric, following the work of Kinnersley and Walker for the flat C-metric. These exact solutions describe a pair of accelerated black holes in the flat or cosmological constant background, with the acceleration A being provided by a strut in-between that pushes away the two black holes. In this paper we analyze the extremal limits of the C-metric in a background with generic cosmological constant. We follow a procedure first introduced by Ginsparg and Perry in which the Nariai solution, a spacetime which is the direct topological product of the 2-dimensional dS and a 2-sphere, is generated from the four-dimensional dS-Schwarzschild solution by taking an appropriate limit, where the black hole event horizon approaches the cosmological horizon. Similarly, one can generate the Bertotti-Robinson metric from the Reissner-Nordstrom metric by taking the limit of the Cauchy horizon going into the event horizon of the black hole, as well as the anti-Nariai by taking an appropriate solution and limit. Using these methods we generate the C-metric counterparts of the Nariai, Bertotti-Robinson and anti-Nariai solutions, among others. One expects that the solutions found in this paper are unstable and decay into a slightly non-extreme black hole pair accelerated by a strut or by strings. Moreover, the Euclidean version of these solutions mediate the quantum process of black hole pair creation, that accompanies the decay of the dS and AdS spaces

Cosmological Black Holes on Branes

We examined analytically a cosmological black hole domain wall system. Using the C-metric construction we derived the metric for the spacetime describing an infinitely thin domain wall intersecting a cosmological black hole. We studied the behaviour of the scalar field describing a self-interacting cosmological domain wall and find the approximated solution valid for large distances. The thin wall approximation and the back raection problem were elaborated finding that the topological kink solution smoothed out singular behaviour of the zero thickness wall using a core topological and hence thick domain wall. We also analyze the nucleation of cosmological black holes on and in the presence of a domain walls and conclude that the domain wall will nucleate small black holes on it rather than large ones inside.Comment: 13 pages, Revtex, to be published in Phys.Rev. D1

Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor