A Gauge Invariant Unitary Theory for Pion Photoproduction

A covariant, unitary and gauge invariant theory for pion photoproduction on a single nucleon is presented. To achieve gauge invariance at the operator level one needs to include both the $\pi N$ and $\gamma\pi N$ thresholds. The final amplitude can be written in terms of a distorted wave in the final $\pi N$ channel provided one includes additional diagrams to the standard Born term in which the photon is coupled to the final state pion and nucleon. These additional diagrams are required in order to satisfy gauge invariance.Comment: 4 pages, LaTeX, 1 figure as a separate uuencoded compressed tar fil

Decay of correlations for maps with uniformly contracting fibers and logarithm law for singular hyperbolic attractors

We consider two dimensional maps preserving a foliation which is uniformly contracting and a one dimensional associated quotient map having exponential convergence to equilibrium (iterates of Lebesgue measure converge exponentially fast to physical measure). We prove that these maps have exponential decay of correlations over a large class of observables. We use this result to deduce exponential decay of correlations for the Poincare maps of a large class of singular hyperbolic flows. From this we deduce logarithm laws for these flows.Comment: 39 pages; 03 figures; proof of Theorem 1 corrected; many typos corrected; improvements on the statements and comments suggested by a referee. Keywords: singular flows, singular-hyperbolic attractor, exponential decay of correlations, exact dimensionality, logarithm la

Associations between insulin and glucose concentrations and anthropometric measures of fat mass in Australian adolescents

<p>Abstract</p> <p>Background</p> <p>One of the most serious, yet common co-morbidities of obesity is insulin resistance, which if untreated may progress to type 2 diabetes. This paper describes the insulin and glucose concentration distributions, the prevalence of elevated insulin, the associations between insulin and body mass index (BMI), waist circumference, waist-to-height ratio (WHtR) and fat mass index in a representative sample of Australian adolescents.</p> <p>Methods</p> <p>Cross-sectional population-based study of adolescent boys and girls (N = 496, mean age 15.3 years) attending schools in metropolitan Sydney, Australia. Fasting venous blood collected and analysed for insulin and glucose concentrations. Height, weight, waist circumference measured, BMI and waist-to-height ratio calculated. Pubertal status self-reported.</p> <p>Results</p> <p>Glucose concentrations were normally distributed and were not associated with adiposity. Insulin concentrations were distributed logarithmically, were higher among girls than boys overall and within the same ranges of BMI and waist circumference, but were lower among girls than boys within the same ranges of fat mass adjusted for height. The prevalence of elevated insulin concentration (defined as > 100 pmol/L) was 15.9% and 17.1% among boys and girls, respectively. Correlations between insulin concentration and BMI, waist circumference, WHtR and fat mass adjusted for height were 0.53, 0.49, 0.51 and 0.55, among boys, respectively, and 0.35, 0.40, 0.42 and 0.34, among girls, respectively.</p> <p>Conclusions</p> <p>Elevated insulin is highly correlated with adiposity in adolescents. BMI and WHtR are simple measures that can be used to identify young people who should be screened for insulin resistance and other co-morbidities.</p

Muon Physics: A Pillar of the Standard Model

Since its discovery in the 1930s, the muon has played an important role in our quest to understand the sub-atomic theory of matter. The muon was the first second-generation standard-model particle to be discovered, and its decay has provided information on the (Vector -Axial Vector) structure of the weak interaction, the strength of the weak interaction, G_F, and the conservation of lepton number (flavor) in muon decay. The muon's anomalous magnetic moment has played an important role in restricting theories of physics beyond the standard standard model, where at present there is a 3.4 standard-deviation difference between the experiment and standard-model theory. Its capture on the atomic nucleus has provided valuable information on the modification of the weak current by the strong interaction which is complementary to that obtained from nuclear beta decay.Comment: 8 pages, 9 figures. Invited paper for the Journal of Physical Society in Japan (JPSJ), Special Topics Issue "Frontiers of Elementary Particle Physics, The Standard Model and beyond

EIF2S3 Mutations Associated with Severe X-Linked Intellectual Disability Syndrome MEHMO

Impairment of translation initiation and its regulation within the integrated stress response (ISR) and related unfolded-protein response has been identified as a cause of several multisystemic syndromes. Here, we link MEHMO syndrome, whose genetic etiology was unknown, to this group of disorders. MEHMO is a rare X-linked syndrome characterized by profound intellectual disability, epilepsy, hypogonadism and hypogenitalism, microcephaly, and obesity. We have identified a C-terminal frameshift mutation (Ile465Serfs) in the EIF2S3 gene in three families with MEHMO syndrome and a novel maternally inherited missense EIF2S3 variant (c.324T>A; p.Ser108Arg) in another male patient with less severe clinical symptoms. The EIF2S3 gene encodes the gamma subunit of eukaryotic translation initiation factor 2 (eIF2), crucial for initiation of protein synthesis and regulation of the ISR. Studies in patient fibroblasts confirm increased ISR activation due to the Ile465Serfs mutation and functional assays in yeast demonstrate that the Ile465Serfs mutation impairs eIF2gamma function to a greater extent than tested missense mutations, consistent with the more severe clinical phenotype of the Ile465Serfs male mutation carriers. Thus, we propose that more severe EIF2S3 mutations cause the full MEHMO phenotype, while less deleterious mutations cause a milder form of the syndrome with only a subset of the symptoms

Energy performance contracting (EPC): a suitable mechanism for achieving energy savings in housing cooperatives? Results from a Norwegian pilot project

The barriers to energy savings in institutions and private homes are well known and include people’s lack of interest, awareness, knowledge and human and financial capacity. Experiences made in several countries show that EPC—energy performance contracting—may be used for overcoming many of these barriers. A typical EPC project is delivered by an energy service company (ESCO) and the contract is accompanied with a guarantee for energy savings. EPC is increasingly taken in use in the professional market (firms and the public sector), but is less common in the residential sector market. It has been suggested that there are several barriers for using EPC in the domestic sector such as the uncertainty involved in estimating forthcoming reductions in private consumption. In this paper, we present the results from a pilot project on the use of EPC in a housing cooperative in Oslo. The project was initiated and observed by the researchers. The research followed a transdisciplinary methodology in that it was conducted by both researcher and practitioner (co-authors) in close collaboration with members of the housing cooperative and the ESCOs, who also contributed to the interpretation of results. We document the process in terms of why the Board decided to join the EPC pilot, the call for offers from ESCOs who guaranteed that purchased annual energy would be reduced by one third, the responses to and negotiations of the offer from the ESCO who became contracted in the initial phase and up to the moment when the General Assembly finally decided to not invest in the proposed energy saving measures. We find that the residents not only had limited interest in energy savings but also lacked confidence in the EPC process. This contributed to the outcome. We discuss the findings in relation to the barriers to using EPC among housing cooperatives. We highlight the need for more knowledge about the client side for understanding how barriers may be overcome. Three specific recommendations for how EPC may successfully be employed among housing cooperatives are suggested as follows: (i) include refurbishment and not only energy savings in the EPC, (ii) identify the residents’ needs in an early phase and (iii) communicate the EPC principle to the residents throughout the process

Novel materials for solid oxide fuel cells cathodes and oxygen separation membranes: Fundamentals of oxygen transport and performance

In the field of modern hydrogen energy, obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems. Developing solid oxide fuel cells (SOFC) and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems. In this work, the authors’ recent studies in this field are reviewed; the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’ permselective layers based on research of their oxygen mobility and surface reactivity are presented. Ruddlesden – Popper phases Ln2–xCaxNiO4+δ (LnCNO) and perovskite-fluorite nanocomposites PrNi0.5Co0.5O3–δ–Ce0.9Y0.1O2–δ (PNC–YDC) were studied by isotope exchange of oxygen with C18O2 and 18O2 in flow and closed reactors. For LnCNO a high oxygen mobility was shown (D* ~ 10–7 cm2/s at 700 °C), being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen. For PNC–YDC dominated a wide fast diffusion channel via fluorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility (D* ~ 10–8 cm2/s at 700 °C). After optimization of composition and nanodomain structure of these materials, as cathodes of SOFC they provided a high power density, while for asymmetric supported oxygen separation membranes – a high oxygen permeability. © 2020Support of different parts of the work by the Russian Science Foundation (Project 16-13-00112) and the budget project №AAAA-A17-117041110045-9 for Boreskov Institute of Catalysis is gratefully acknowledged. The authors from the Ural Federal University are grateful to the Government of the Russian Federation (Agreement 02.A03.21.0006, Act 211). Ce 0.9 Y 0.1 O 2–δ |Ce 0.9 Gd 0.1 O 2–δ |Ni/Zr 0.84 Y 0.16 O 2–δ anodic half-cells and Ni/Al foam substrates were kindly provided by H.C. Starck, Germany and Powder Metallurgy Institute NAN Belarus, respectively. Authors would like to appreciate International Conference on Advances in Energy Systems and Environmental Engineering (ASEE19, Wroclaw, Poland, June 9-12, 2019) Organization Committee