Time variation of the fine structure constant in the early universe and the Bekenstein model

We calculate bounds on the variation of the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We use these bounds and other bounds from the late universe to test Bekenstein model. We modify the Kawano code, CAMB and CosmoMC in order to include the possible variation of the fine structure constant. We use observational primordial abundances of \De, \He and \Li, recent data from the Cosmic Microwave Background and the 2dFGRS power spectrum, to obtain bounds on the variation of $\alpha$. We calculate a piecewise solution to the scalar field equation of Bekenstein model in two different regimes; i) matter and radiation, ii) matter and cosmological constant. We match both solutions with appropriate boundary conditions. We perform a statistical analysis using the bounds obtained from the early universe and other bounds from the late universe to constrain the free parameters of the model. Results are consistent with no variation of $\alpha$ in the early universe. Limits on $\alpha$ are inconsistent with the scale length of the theory $l$ being larger than Planck scale. In order to fit all observational and experimental data, the assumption $l>L_p$ implied in Bekenstein's model has to be relaxed.Comment: 13 pages, 8 figures,version accepted to be published in Astronomy and Astrophysic

Restoration of the seagrass Amphibolis antarctica - temporal variability and long-term success

The loss of seagrass meadows is an increasing problem worldwide. The important role that these meadows play in coastal ecosystems has resulted in substantial attention to the development of seagrass restoration techniques. Here, I present long-term (up to 5 years) results of seagrass restoration off the coast of Adelaide, South Australia, where >5,000 ha of seagrass has been lost and where trials of traditional restoration techniques using seeds and transplants have failed due to high levels of sand and water movement. Hessian (burlap) sandbags were deployed bimonthly (with some interruptions) from November 2007 to November 2012 (a total of 24 deployments), with a mix of single- and double-layered bags, to provide a stable substrate for naturally occurring Amphibolis seedlings to recruit to. At the end of the study (January 2013), bags deployed in August 2009 had similar stem densities to those found in adjacent natural meadows (15.2 ± 1.4 (SE) vs 18.6 ± 2.5). Bags deployed in May 2008 and August 2011 had 12.8 ± 2.3 and 13.2 ± 2.2 stems, respectively. Furthermore, stem lengths on older bags were greater than those on natural meadows (42.1 ± 4.2 after 62 months vs 30.2 ± 1.5 cm). While there was some interannual variation in recruitment success, the strongest predictor of success was deployment month. Bags deployed outside the austral winter recruitment season did not retain the ability to catch a large number of recruits, indicating that any restoration using this technique will have to be undertaken between approximately May and August to maximize chances of success.Jason E. Tanne

Diagnosis and Treatment of the Intracranial Compartment Syndrome

The intracranial compartment syndrome is a condition characterized by a set of clinical symptoms and signs due to a rise in intracranial pressure (ICP). Intracranial hypertension is a life-treating condition that requires quick diagnosis and treatment; otherwise, it may progress in herniation syndrome and death. Consequently, timely recognition and management of elevated ICP is the first goal in order to maintain good cerebral perfusion pressure and to prevent irreversible secondary cerebral insult. Several pathologies may cause raised ICP, and it is fundamental to treat the specific underlying disease. Therefore, neuromonitoring assumes paramount significance for the rapid detection of harmful events and for a quick evaluation of the efficacy of medical treatment. In this chapter, we aimed to provide an overview of the current knowledge regarding the diagnosis and treatment of intracranial compartment syndrome

Individualism-collectivism as a moderator of the work demands-strains relationship: A cross-level and cross-national examination

Item does not contain fulltextSurveying 6509 managers from 24 countries/geopolitical entities, we tested the process through which individualism-collectivism at the country level relates to employees' appraisals of and reactions to three types of work demands (i.e., work hours, workload, and organizational constraints). Our multilevel modeling results suggested that, while working the same number of hours, employees from individualistic countries reported a higher perceived workload than their counterparts in collectivistic countries. Furthermore, relationships of perceived workload and organizational constraints with job dissatisfaction and turnover intentions were stronger in individualistic than in collectivistic countries. Importantly, results of supplementary analyses suggested that the cultural value of individualism-collectivism moderated the mediation effect of perceived workload between work hours and both job dissatisfaction and turnover intentions. Our findings highlight the need to expand contemporary theories of work stress by applying multilevel approaches and incorporating cross-national differences in dimensions such as individualism-collectivism while studying how employees appraise and react to important work stressors.20 p

Reproductive, dispersal and recruitment strategies in Australian seagrasses

Seagrasses are a relatively small group of marine angiosperms that have successfully colonised the oceans and includes monecious, dioecious and hermaphroditic species. They display a range of mating systems, dispersal mechanisms and recruitment strategies that have allowed them to adapt and survive within the marine environment. This includes a general reduction in the size and complexity of floral structures, and subsurface pollination (hydrophily) in the majority of species. Fertilisation occurs through water-dispersed pollen that is typically filamentous and sticky, however, recent work has also suggested that marine invertebrates may play a role in pollen movement and fertilisation. Seed size and morphology varies widely among species, from fleshy floating fruit (e.g. Posidonia) to small negatively buoyant seeds less than 0.5 mm (e.g. Halophila). Nearly all species retain some capacity of asexual reproduction through rhizome elongation or the production of asexual fragment or propagules that can be more widely dispersed. These differences in reproductive strategies have important effects on recruitment and dispersal potential and subsequent population dynamics. Direct estimates of dispersal and recruitment are inherently difficult to assess in seagrasses, but the use of novel genetic and predictive modelling approaches are providing new insights into these important processes. This chapter highlights the main reproductive strategies and adaptations seagrass have undergone in response to reproducing in a marine environment, with an emphasis on Australian seagrass species. We highlight the current state of knowledge in Australian seagrass reproductive biology and future directions in seagrass reproductive biology research

Consensus and diversity in the management of varicocele for male infertility: Results of a global practice survey and comparison with guidelines and recommendations

Purpose: Varicocele is a common problem among infertile men. Varicocele repair (VR) is frequently performed to improve semen parameters and the chances of pregnancy. However, there is a lack of consensus about the diagnosis, indications for VR and its outcomes. The aim of this study was to explore global practice patterns on the management of varicocele in the context of male infertility. Materials and Methods: Sixty practicing urologists/andrologists from 23 countries contributed 382 multiple-choice-questions pertaining to varicocele management. These were condensed into an online questionnaire that was forwarded to clinicians involved in male infertility management through direct invitation. The results were analyzed for disagreement and agreement in practice patterns and, compared with the latest guidelines of international professional societies (American Urological Association [AUA], American Society for Reproductive Medicine [ASRM], and European Association of Urology [EAU]), and with evidence emerging from recent systematic reviews and meta-analyses. Additionally, an expert opinion on each topic was provided based on the consensus of 16 experts in the field. Results: The questionnaire was answered by 574 clinicians from 59 countries. The majority of respondents were urologists/uro-andrologists. A wide diversity of opinion was seen in every aspect of varicocele diagnosis, indications for repair, choice of technique, management of sub-clinical varicocele and the role of VR in azoospermia. A significant proportion of the responses were at odds with the recommendations of AUA, ASRM, and EAU. A large number of clinical situations were identified where no guidelines are available. Conclusions: This study is the largest global survey performed to date on the clinical management of varicocele for male infertility. It demonstrates: 1) a wide disagreement in the approach to varicocele management, 2) large gaps in the clinical practice guidelines from professional societies, and 3) the need for further studies on several aspects of varicocele management in infertile men