Inflationary Baryogenesis in a Model with Gauged Baryon Number

We argue that inflationary dynamics may support a scenario where significant matter-antimatter asymmetry is generated from initially small-scale quantum fluctuations that are subsequently stretched out over large scales. This scenario can be realised in extensions of the Standard Model with an extra gauge symmetry having mixed anomalies with the electroweak gauge symmetry. Inflationary baryogenesis in a model with gauged baryon number is considered in detail.Comment: 11 pages, V3 - major revisio

Pendulum Leptogenesis

We propose a new non-thermal Leptogenesis mechanism that takes place during the reheating epoch, and utilizes the Ratchet mechanism. The interplay between the oscillation of the inflaton during reheating and a scalar lepton leads to a dynamical system that emulates the well-known forced pendulum. This is found to produce driven motion in the phase of the scalar lepton which leads to the generation of a non-zero lepton number density that is later redistributed to baryon number via sphaleron processes. This model successfully reproduces the observed baryon asymmetry, while simultaneously providing an origin for neutrino masses via the seesaw mechanism.Comment: 14 pages, no figures; minor revision to match PL

Exotic Lepton Searches via Bound State Production at the LHC

Heavy long-lived multi-charged leptons (MCLs) are predicted by various new physics models. These hypothetical MCLs can form bound states, due to their high electric charges and long life times. In this work, we propose a novel strategy of searching for MCLs through their bound state productions and decays. By utilizing LHC-8 TeV data in searching for resonances in the diphoton channel, we exclude the masses of isospin singlet heavy leptons with electric charge $|q|\geq 6$ (in units of electron charge) lower than $\sim$1.2 TeV, which are much stronger than the corresponding 8 TeV LHC bounds from analysing the high ionisation and the long time-of-flight of MCLs. By utilising the current 13 TeV LHC diphoton channel measurements the bound can further exclude MCL masses up to $\sim$1.6 TeV for $|q|\geq 6$. Also, we demonstrate that the conventional LHC limits from searching for MCLs produced via Drell-Yan processes can be enhanced by including the contribution of photon fusion processes.Comment: 9 pages, 3 figures, Updated to match PL

Minimally invasive reduction and percutaneous fixation versus open reduction and internal fixation for displaced intra-articular calcaneal fractures : a systematic review of the literature

The aim of this article is to systematically identify and analyse research evidence available to compare the outcomes of minimally invasive reduction and percutaneous fixation (MIRPF) versus open reduction and internal fixation (ORIF) for displaced intra-articular calcaneal fractures. Articles from 2000 to 2016 were searched through MEDLINE (PubMed), Cochrane Library, Embase, ScienceDirect, Scopus and ISI Web of Knowledge using Boolean logic and text words. Of the 570 articles identified initially, nine were selected including three randomized controlled trials and six retrospective comparative studies. All nine studies had a total of 1,031 patients with 1,102 displaced intra-articular calcaneal fractures. Mean follow-up was 33 months. Of these, 602 (54.6%) were treated with MIRPF and 500 (45.4%) were treated with ORIF. Overall incidence of wound-related complications in patients treated with MIRPF was 4.3% (0% to 13%) compared with 21.2% (11.7% to 35%) in the ORIF group Functional outcomes were reported to be better in the minimally invasive group in all studies; however, the results did not reach statistical significance in some studies. All the studies had methodological flaws that put them at either ‘unclear’ or ‘high’ risk of bias for multiple domains. Overall quality of the available evidence is poor in support of either surgical technique due to small sample size, flaws in study designs and high risk of bias for various elements. Individual studies have reported minimally invasive techniques to be an effective alternative with lower risk of wound complications and better functional outcomes.</ul

Influence of transport and ocean ice extent on biogenic aerosol sulfur in the Arctic atmosphere

The recent decline in sea ice cover in the Arctic Ocean could affect the regional radiative forcing via changes in sea ice-atmosphere exchange of dimethyl sulfide (DMS) and biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonic acid (MSA). This study examines relationships between changes in total sea ice extent north of 70 degrees N and atmospheric MSA measurement at Alert, Nunavut, during 1980-2009; at Barrow, Alaska, during 1997-2008; and at Ny-Alesund, Svalbard, for 1991-2004. During the 1980-1989 and 1990-1997 periods, summer (July-August) and June MSA concentrations at Alert decreased. In general, MSA concentrations increased at all locations since 2000 with respect to 1990 values, specifically during June and summer at Alert and in summer at Barrow and Ny-Alesund. Our results show variability in MSA at all sites is related to changes in the source strengths of DMS, possibly linked to changes in sea ice extent as well as to changes in atmospheric transport patterns. Since 2000, a late spring increase in atmospheric MSA at the three sites coincides with the northward migration of the marginal ice edge zone where high DMS emissions from ocean to atmosphere have previously been reported. Significant negative correlations are found between sea ice extent and MSA concentrations at the three sites during the spring and June. These results suggest that a decrease in seasonal ice cover influencing other mechanisms of DMS production could lead to higher atmospheric MSA concentrations

Does digital video enhance student learning in field-based experiments and develop graduate attributes beyond the classroom?

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 02/05/2016, available online: http://www.tandfonline.com/doi/full/10.1080/03098265.2016.1141186?src=recsysThe connection between fieldwork and development of graduate attributes is explored in this paper. Digital technologies present opportunities to potentially enhance the learning experience of students undertaking fieldwork, and develop core digital attributes and competencies required by Higher Education Institutions (HEIs) and employers. This paper reports the success of adopting digital video capture in technology-rich field experiments that form part of final year undergraduate courses in Physical Geography at an HEI in New Zealand. Student perceptions were obtained via a range of approaches. Results suggest that deployment of digital video reinforces student learning and connects with core graduate attributes

Functional Optimization in Complex Excitable Networks

We study the effect of varying wiring in excitable random networks in which connection weights change with activity to mold local resistance or facilitation due to fatigue. Dynamic attractors, corresponding to patterns of activity, are then easily destabilized according to three main modes, including one in which the activity shows chaotic hopping among the patterns. We describe phase transitions to this regime, and show a monotonous dependence of critical parameters on the heterogeneity of the wiring distribution. Such correlation between topology and functionality implies, in particular, that tasks which require unstable behavior --such as pattern recognition, family discrimination and categorization-- can be most efficiently performed on highly heterogeneous networks. It also follows a possible explanation for the abundance in nature of scale--free network topologies.Comment: 7 pages, 3 figure

A case in support of implementing innovative bio-processes in the metal mining industry

The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as waste (rock dumps and mineral tailings). Exposure of these to air and water frequently leads to the formation of acidic, metal-contaminated run-off waters, referred to as acid mine drainage, which constitutes a severe threat to the environment. Formation of acid drainage is a natural phenomenon involving various species of lithotrophic (literally rock-eating) bacteria and archaea, which oxidise reduced forms of iron and/or sulfur. However, other microorganisms that reduce inorganic sulfur compounds can essentially reverse this process. These microorganisms can be applied on industrial scale to precipitate metals from industrial mineral leachates and acid mine drainage streams, resulting in a net improvement in metal recovery, while minimising the amounts of leachable metals to the tailings storage dams. Here, we advocate that more extensive exploitation of microorganisms in metal mining operations could be an important way to green up the industry, reducing environmental risks and improving the efficiency and the economy of metal recovery.Research of AJMS and ISA was supported by European Research Council (ERC) grant [project 323009] and Gravitation grant [project 024.002.002] from the Netherlands Ministry of Education, Culture and Science