Neutrino masses and lepton flavour violating phenomena in the MSSM

The most general supersymmetric model with minimal particle content and an additional discrete Ƶ(_3) symmetry, which allows lepton number violating terms, is considered. In this model, we calculate at the level of one-loop the resulting Majorana neutrino masses and the flavour violating radiative decays of charged leptons, ﺎ→ﺎ’γ. We first study the neutral scalar sector of the model, performing a calculable rotation of the scalar fields to a basis in which the sneutrino vacuum expectation values are zero. Lagrangian parameters are initialised without recourse to assumptions concerning trilinear or bilinear terms, CP-conservation or intergenerational mixing and one-loop corrections to the neutrino masses are analysed. We present scenarios in which the experimental data are reproduced. We find that with bilinear lepton number violating couplings in the superpotential of the order 1MeV the atmospheric mass scale can be reproduced. Certain trilinear superpotential couplings, usually of the order of the electron Yukawa coupling can give rise to either atmospheric or solar mass scales and bilinear supersymmetry breaking terms of the order 0.1 GeV(^2) can set the solar mass scale. Taking parameters which correctly describe the neutrino sector, we consider their repercussions in flavour violating radiative lepton decays. Such decays have not been observed and upper bounds on their branching ratios exist. We note that certain parameter sets, which correctly describe the neutrino sector, will also generate observable branching ratios and suggest four such sets as Benchmarks scenarios. We present as Appendices the full set of Feynman Rules for the general super- symmetric standard model with minimal particle content and details of the loop calculations in the Weyl spinor notation

Ingestion of sodium bicarbonate (NaHCO3) following a fatiguing bout of exercise accelerates post-exercise acid-base balance recovery and improves subsequent high-intensity cycling time to exhaustion.

This study evaluated the ingestion of sodium bicarbonate (NaHCO3) on post-exercise acid-base balance recovery kinetics and subsequent high-intensity cycling time to exhaustion. In a counterbalanced, crossover design, nine healthy and active males (age: 23±2 years, height: 179±5 cm, body mass: 74±9 kg, peak mean minute power (WPEAK) 256±45 W, peak oxygen uptake (V̇O2PEAK) 46±8 ml.kg-1.min-1) performed a graded incremental exercise test, two familiarisation and two experimental trials. Experimental trials consisted of cycling to volitional exhaustion (TLIM1) at 100% WPEAK on two occasions (TLIM1 and TLIM2) interspersed by a 90 min passive recovery period. Using a double blind approach, 30 min into a 90 min recovery period participants ingested either 0.3 g.kg-1 body mass sodium bicarbonate (NaHCO3) or a placebo (PLA) containing 0.1 g.kg-1 body mass sodium chloride (NaCl) mixed with 4 ml.kg-1 tap water and 1 ml.kg-1 orange squash. The mean differences between TLIM2 and TLIM1 was larger for PLA compared to NaHCO3 (-53±53 vs. -20±48 s; P=0.008, d=0.7, CI=-0.3, 1.6), indicating superior subsequent exercise time to exhaustion following NaHCO3. Blood lactate [BLa-] was similar between treatments post TLIM1, but greater for NaHCO3 post TLIM2 and 5 min post TLIM2. Ingestion of NaHCO3 induced marked increases (P<0.01) in both blood pH (+0.07±0.02, d=2.6, CI=1.2, 3.7) and bicarbonate ion concentration [HCO3-] (+6.8±1.6 mmo.l-1, d=3.4, CI=1.8, 4.7) compared to the PLA treatment, prior to TLIM2. It is likely both the acceleration of recovery and the marked increases of acid-base after TLIM1 contributed to greater TLIM2 performance compared to the PLA condition.The authors received no external funding for this research. Mr. Steven Rimmer received a small undergraduate research bursary from the University of Derby to fund his contribution to the study

Neutrino masses in the Lepton Number Violating MSSM

We consider the most general supersymmetric model with minimal particle content and an additional discrete Z_3 symmetry (instead of R-parity), which allows lepton number violating terms and results in non-zero Majorana neutrino masses. We investigate whether the currently measured values for lepton masses and mixing can be reproduced. We set up a framework in which Lagrangian parameters can be initialised without recourse to assumptions concerning trilinear or bilinear superpotential terms, CP-conservation or intergenerational mixing and analyse in detail the one loop corrections to the neutrino masses. We present scenarios in which the experimental data are reproduced and show the effect varying lepton number violating couplings has on the predicted atmospheric and solar mass^2 differences. We find that with bilinear lepton number violating couplings in the superpotential of the order 1 MeV the atmospheric mass scale can be reproduced. Certain trilinear superpotential couplings, usually, of the order of the electron Yukawa coupling can give rise to either atmospheric or solar mass scales and bilinear supersymmetry breaking terms of the order 0.1 GeV^2 can set the solar mass scale. Further details of our calculation, Lagrangian, Feynman rules and relevant generic loop diagrams, are presented in three Appendices.Comment: 48 pages, 7 figures, v2 references added, typos corrected, published versio

Advantages of block copolymer synthesis by RAFT-controlled dispersion polymerization in supercritical carbon dioxide

Reversible addition-fragmentation chain transfer (RAFT)-controlled block copolymer synthesis using dispersion polymerization in supercritical carbon dioxide (scCO2) shows unprecedented control over blocking efficiency. For PMMA-b-PBzMA and PMMA-b-PSt the blocking efficiency was quantified by measuring homopolymer contaminants using the techniques of GPC deconvolution, gradient polymer elution chromatography (GPEC), and GPC dual RI/UV detection. A new, promising method was also developed which combined GPC deconvolution and GPEC. All techniques showed that blocking efficiency was significantly improved by reducing the radical concentration and target molecular weight. Estimated values agreed well with (and occasionally exceeded) theory for PMMA-b-PBzMA. The heterogeneous process in scCO2 appeared to cause little or no further hindrance to the block copolymerization procedure when reaction conditions were optimized. High blocking efficiencies were achieved (up to 82%) even at high conversion of MMA (>95%) and high molecular weight. These data compare favorably to numerous published reports of heterogeneous syntheses of block copolymers

Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

YesRapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability

How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

High-power beam injectors for 100 KW free-electron lasers

A key technology issue on the path to high-power FEL operation is the demonstration of reliable, high-brightness, high-power injector operation. We describe two ongoing programs to produce 100 mA injectors as drivers for 100 kW free-electron lasers. In one approach, in collaboration with the Thomas Jefferson National Accelerator Facility, we are fabricating a 750 MHz superconducting RF cryomodule that will be integrated with a room-temperature DC photocathode gun and tested at the Laboratory. In the other approach, in collaboration with Los Alamos National Laboratory, a high-current 700 MHz, normal-conducting, RF photoinjector is being designed and will undergo thermal management testing at the Laboratory. We describe the design, the projected performance and the status of both injectors