Bipartite entangled stabilizer mutually unbiased bases as maximum cliques of Cayley graphs

We examine the existence and structure of particular sets of mutually unbiased bases (MUBs) in bipartite qudit systems. In contrast to well-known power-of-prime MUB constructions, we restrict ourselves to using maximally entangled stabilizer states as MUB vectors. Consequently, these bipartite entangled stabilizer MUBs (BES MUBs) provide no local information, but are sufficient and minimal for decomposing a wide variety of interesting operators including (mixtures of) Jamiolkowski states, entanglement witnesses and more. The problem of finding such BES MUBs can be mapped, in a natural way, to that of finding maximum cliques in a family of Cayley graphs. Some relationships with known power-of-prime MUB constructions are discussed, and observables for BES MUBs are given explicitly in terms of Pauli operators.Comment: 8 pages, 1 figur

Primitive decompositions of Johnson graphs

A transitive decomposition of a graph is a partition of the edge set together with a group of automorphisms which transitively permutes the parts. In this paper we determine all transitive decompositions of the Johnson graphs such that the group preserving the partition is arc-transitive and acts primitively on the parts.Comment: 35 page

Photospheric albedo and the measurement of energy and angular electron distributions in solar flares

In this thesis I examine the role of Compton back-scatter of solar flare Hard X-rays, also known as albedo, in the inference of the parent electron spectrum. I consider how albedo affects measurements of the energy and angular distributions when the mean electron flux spectrum in a solar flare is inferred using regularised inversion techniques. The angular distribution of the accelerated electron spectrum is a key parameter in the understanding of the acceleration and propagation mechanisms that occur in solar flares. However, the anisotropy of energetic electrons is still a poorly known quantity, with observational studies producing evidence for an isotropic distribution and theoretical models mainly considering the strongly beamed case. First we investigate the effect of albedo on the observed spectrum for a variety of commonly considered analytic forms of the pitch angle distribution. As albedo is the result of the scattering of X-ray photons emitted downwards towards the photosphere different angular distributions are likely to exhibit a varying amount of albedo reflection, in particular, downward directed beams of electrons are likely to produce spectra which are strongly influenced by albedo. The low-energy cut-off of the non-thermal electron spectrum is another significant parameter which it is important to understand, as its value can have strong implications for the total energy contained in the flare. However, both albedo and a low energy cut-off will cause a flattening of the observed X-ray spectrum at low energies. The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) X-ray data base has been searched to find solar flares with weak thermal components and flat photon spectra in the 15 - 20 keV energy range. Using the method of Tikhonov Regularisation, we determine the mean electron flux distribution from count spectra of a selection of these events. We have found 18 cases which exhibit a statistically significant local minimum (a dip) in the range of 10 - 20 keV. The positions and spectral indices of events with low-energy cut-off indicate that such features are likely to be the result of photospheric albedo. It is shown that if the isotropic albedo correction was applied, all low-energy cut-offs in the mean electron spectrum were removed. The effect of photospheric albedo on the observed X-ray spectrum suggest RHESSI observations can be used to infer the anisotropy in the angular distribution of X-ray emitting electrons. A bi-directional approximation is applied and regularized inversion is performed for eight large flare events viewed by RHESSI to deduce the electron spectra in both downward (towards the photosphere) and upward (away form the photosphere) directions. The electron spectra and the electron anisotropy ratios are calculated for broad energy range from about 10 and up to ~ 300 keV near the peak of the flares. The variation of electron anisotropy over short periods of time intervals lasting 4, 8 and 16 seconds near the impulsive peak has been examined. The results show little evidence for strong anisotropy and the mean electron flux spectra are consistent with the isotropic electron distribution. The inferred X-ray emitting electron spectrum is likely to have been modified from the accelerated or injected distribution by transport effects thus models of electron transport are necessary to connect the observations. We use the method of stochastic simulations to investigate the effect of Coulomb collisions on an electron beam propagating through a coronal loop. These simulations suggest that the effect of Coulomb collisions on a uniformly downward directed beam as envisaged in the collisional thick target model is not strong enough to sufficiently scatter the pitch angle distribution to be consistent with the measurements made in the previous chapter. Furthermore these simulations suggest that for the conditions studied the constraints inferred in Chapter 4 are only consistent with a low level of anisotropy in the injected electron distribution

Influence of electrode processing and electrolyte composition on multiwall carbon nanotube negative electrodes for sodium ion batteries

Dr. A. Fuente Cuesta would like to thank Agency for Green Technology (AGT), Dr. S. A. M. Dickson would like to thank the Faraday Institution NEXGENNA project (FIRG018), and C. Lonsdale would like to thank the Faraday Institution FUSE Internship Programme for funding. The authors also acknowledge the EPSRC (grant codes EP/L017008/1, EP/T019298/1, and EP/R023751/1).Nanostructured one-dimensional multiwall-carbon nanotubes have a variety of advantageous properties including good electrical conductivity and mechanical strength, and thus have been widely investigated for use in lithium-ion battery electrodes as conductive and microstructural additives, though also possess some electrochemical activity. Their application to sodium-ion batteries has been less extensively researched, and therefore a greater understanding of the electrochemical reaction with sodium, and effects of slurry composition and electrolyte formulation is warranted. Here, we report the fabrication of aqueous and organic multi-wall carbon nanotube negative electrodes processed by ball milling. The binder of choice is noted to greatly affect the electrochemical performance, both in terms of capacity retention and rate capability over a range of current densities from 25 to 500 mA g-1. Switching from a carbonate- to diglyme-based electrolyte considerably improves initial coulombic efficiencies (~10 to 60%), attributed to less extensive formation of solid electrolyte interphase, and enables a reversible mechanism with capacities up to 150 mAh g-1 over 100 cycles depending upon the binder used.Publisher PDFPeer reviewe

Symptom Recognition in Elders with Heart Failure

Purpose: Aging is associated with losses in hearing and vision. The objective of this study was to assess whether aging also is associated with less ability to detect and interpret afferent physiological information. Design: A cross‐sectional mixed methods study was conducted with 29 persons with a confirmed diagnosis of chronic heart failure of at least 6 months duration. The sample was divided at the median to compare younger (\u3c73 years) versus older (≥73 years) patients in the ability to detect and interpret their heart failure symptoms. Methods: Shortness of breath was stimulated using a 6‐minute walk test (6MWT) and used to assess the ability of heart failure patients to detect shortness of breath using the Borg measure of perceived exertion compared with gold standard ratings of each person\u27s shortness of breath by trained registered nurse research assistants (inter‐rater congruence 0.91). Accuracy of ratings by older patients was compared with those of younger patients. In‐depth interviews were used to assess symptom interpretation ability. Findings: Integrated quantitative and qualitative data confirmed that older patients had more difficulty in detecting and interpreting shortness of breath than younger patients. Older patients were twice as likely as younger to report a different level of shortness of breath than that noted by the registered nurse research assistants immediately after the 6MWT. Conclusions: These results support our theory of an age‐related decline in the ability to attend to internal physical symptoms. This decline may be a cause of poor early symptom detection. Clinical Relevance: The results of this study suggest that there is a need to develop interventions that focus on the symptom experience to help patients—particularly older ones—in somatic awareness and symptom interpretation. It may be useful to explore patients’ statements about how they feel: “Compared to what? How do you feel today compared to yesterday?

Native Birdlife in Hawke’s Bay: application of the river values assessment system (RiVAS and RiVAS+)

This report presents an application of the River Values Assessment System for existing value (RiVAS) and for potential value (RiVAS+) to native birdlife in the Hawkes Bay Region. A workshop was held in Napier on 3rd October 2011 to apply the method. This Hawkes Bay Region bird report needs to be read in conjunction with the method and with the first native bird application reports (see Hughey et al. 2010 and Gaze et al. 2010).Ministry of Science and Information, and Hawkes Bay Regional Counci

Depression increases the genetic susceptibility to high body mass index: evidence from UK Biobank

Background This study aimed to explore the association between depression and body mass index (BMI), and to investigate whether genetic susceptibility to high BMI is different among individuals with or without depression. Methods We used data on 251,125 individuals of white British ancestry from the UK Biobank. We conducted Mendelian randomization (MR) analysis to test for a causal association between depression and BMI using a major depressive disorder (MDD)‐related genetic risk score (GRSMDD) as an instrument for depression. We also examined whether depression modifies genetic susceptibility to high BMI, by investigating the interaction between depression and the BMI‐related GRSBMI. Results We found observational and genetic evidence for an association between depression and BMI (MR beta: 0.09, 95% confidence interval [CI] 0.04–0.13). Further, the contribution of genetic risk to high BMI was higher among individuals with depression compared to controls. Carrying 10 additional BMI increasing alleles was associated with 0.24 standard deviation (SD; 95%CI 0.23–0.25) higher BMI among depressed individuals compared to 0.20 SD (95%CI 0.19–0.21) higher in controls, which corresponds to 3.4 kg and 2.8 kg extra weight for an individual of average height. Amongst the individual loci, the evidence for interaction was most notable for a variant near MC4R, a gene known to affect both appetite regulation and the hypothalamic‐pituitary adrenal axis (pinteraction = 5.7 × 10−5). Conclusion Genetic predisposition to high BMI was higher among depressed than to nondepressed individuals. This study provides support for a possible role of MC4R in the link between depression and obesity

Gender Diferences in Heart Failure Self-Care: A Multinational Cross-Sectional Study

Background Despite a common view that women are better at self-care, there is very little evidence to support or challenge this perspective in the heart failure (HF) population. Objective The purpose of this study was to determine if there are cross-cultural gender differences in self-reported HF self-care and to describe gender differences in the determinants of HF self-care. Design, setting, and participants A secondary analysis was completed of cross-sectional study data collected on 2082 adults with chronic HF from the United States, Australia and Thailand. Methods Comparisons were made between men and women regarding self-care maintenance, management and confidence as assessed by the Self-Care of Heart Failure Index, as well as the proportion of subjects engaged in adequate self-care. Multivariate comparisons were made to determine if gender explained sufficient variance in HF self-care and the likelihood of reporting adequate self-care, controlling for nine model covariates. Results The sample was comprised of 1306 men and 776 women. Most (73.5%) had systolic or mixed systolic and diastolic HF and 45% had New York Heart Association class III or IV HF. Although small and clinically insignificant gender differences were found in self-care maintenance, gender was not a determinant of any aspect of HF self-care in multivariate models. Married women were 37% less likely to report adequate self-care maintenance than unmarried women. Comorbidities only influenced the HF self-care of men. Being newly diagnosed with HF also primarily affected men. Patients with diastolic HF (predominantly women) had poorer self-care maintenance and less confidence in self-care. Conclusion Differences in HF self-care are attributable to factors other than gender; however, there are several gender-specific determinants of HF self-care that help identify patients at risk for practicing poor self-care