Spectral Properties of Quasiparticle Excitations Induced by Magnetic Moments in Superconductors

The consequences of localized, classical magnetic moments in superconductors are explored and their effect on the spectral properties of the intragap bound states is studied. Above a critical moment, a localized quasiparticle excitation in an s-wave superconductor is spontaneously created near a magnetic impurity, inducing a zero-temperature quantum transition. In this transition, the spin quantum number of the ground state changes from zero to 1/2, while the total charge remains the same. In contrast, the spin-unpolarized ground state of a d-wave superconductor is found to be stable for any value of the magnetic moment when the normal-state energy spectrum possesses particle-hole symmetry. The effect of impurity scattering on the quasiparticle states is interpreted in the spirit of relevant symmetries of the clean superconductor. The results obtained by the non-self-consistent (T matrix) and the self-consistent mean-field approximations are compared and qualitative agreement between the two schemes is found in the regime where the coherence length is longer than the Fermi length.Comment: to appear in Phys. Rev. B55, May 1st (1997

Fasting plasma glucose is an independent predictor for severity of H1N1 pneumonia

<p>Abstract</p> <p>Background</p> <p>The pandemic influenza A (H1N1) virus emerged during 2009 and has spread worldwide. This virus can cause injuries to the lungs, liver, and heart. However, data regarding whether this influenza virus can affect pancreatic islets are limited. We investigated the effects of influenza A (H1N1) pneumonia on fasting plasma glucose (FPG) and islet function, and evaluated possible correlations between biochemical test results and the severity of H1N1 pneumonia.</p> <p>Methods</p> <p>We performed a retrospective analysis of patients either diagnosed with or suspected of having H1N1 pneumonia who were admitted to our hospital in 2009. Possible associations between FPG levels and H1N1 virus infection were assessed by logistic regression. Correlation and regression analyses were used to assess relationships between FPG and biochemical test results. Associations between admission days and significant data were assessed by single factor linear regression. To evaluate effects of H1N1 on pancreatic β-cell function, results of a resistance index (homa-IR), insulin function index (homa-β), and insulin sensitivity index (IAI) were compared between a H1N1 group and a non-H1N1 group by t-tests.</p> <p>Results</p> <p>FPG was significantly positively associated with H1N1 virus infection (OR = 1.377, 95%CI: 1.062-1.786; p = 0.016). FPG was significantly correlated with AST (r = 0.215; p = 0.039), LDH (r = 0.400; p = 0.000), BUN (r = 0.28; p = 0.005), and arterial Oxygen Saturation (SaO₂; r = -0.416; p = 0.000) in the H1N1 group. H1N1 patients who were hypoxemic (SaO₂<93%) had higher FPG levels than those who were not hypoxic (9.82 ± 4.14 vs. 6.64 ± 1.78; p < 0.05). FPG was negatively correlated with SaO₂in the H1N1 group with hypoxia (SaO₂<93; r = -0.497; p = 0.041). SaO₂levels in patients with high FPG levels (≥7 mmol/L) were significantly lower than those of H1N1 patients with low FPG levels (<5.6 mmol/L). There were no significant differences in homa-IR, homa-β, or IAI between the H1N1 and non-H1N1 groups after adjusting for age, sex, and BMI.</p> <p>Conclusions</p> <p>FPG on admission could be an independent predictor for the severity of H1N1 pneumonia. Elevated FPG induced by H1N1 pneumonia is not a result of direct damage to pancreatic β-cells, but arises from various factors' combinations caused by H1N1 virus infection.</p

The predicament of primary physical education: a consequence of 'insufficient' ITT and 'ineffective' CPD?

Background: Research on primary physical education (PE) in England and other countries has shown that it is an aspect of the curriculum that has suffered from sparse initial teacher training (ITT). As a consequence of ‘insufficient’ time spent on PE in ITT (PE-ITT), primary teachers often have low levels of confidence and competence with respect to teaching the subject. Evidence also points to inadequacies in traditional forms of professional development in PE (PE-CPD), leading to calls for more effective ways of developing teachers' competence to deliver high quality PE. Purpose: To explore primary school teachers' experiences of PE during ITT and the PE context in their schools prior to them engaging in a national PE-CPD programme, and their perceptions of the immediate and longer-term effects of this programme. Setting and participants: Primary school teachers in five local education authorities in England. Research design and data collection: A combination of quantitative and qualitative methodological approaches were adopted, including: pre-course audits, course evaluations, focus groups and semi-structured interviews. The pre-course audits captured information about the teachers' experiences of PE-ITT and the PE context in their schools prior to them engaging in the CPD. The course evaluations focused on initial impressions of the PE-CPD, and the focus groups and interviews captured the teachers' perceptions of its longer-term effects. Findings: For up to half of the teachers, their PE-ITT was ‘insufficient’ in terms of the time dedicated to it and the breadth of coverage of the subject. The PE-CPD programme, which was designed in the light of ‘insufficient’ PE-ITT, demonstrated features of ‘effective’ CPD in that it was considered relevant to classroom practice and partially addressed some of their many needs (especially in relation to content ideas and inclusive practice). However, its effectiveness was undoubtedly limited due to: its short time span and minimal engagement with teachers; a heavy reliance on resources; and the absence of follow-up support. In addition, it did not adequately address known areas of development for primary PE (such as medium to long-term planning and assessment) and was challenged in meeting the diverse needs of primary teachers of 5–11 year olds. Furthermore, inadequate PE time and reduced opportunities to teach PE in some schools limited implementation of learning from the PE-CPD. Conclusions: The findings of this study confirmed that PE-ITT continues to be ‘insufficient’ for many primary teachers and that the PE-CPD in question, whilst partially ‘effective’, was not, and could never have been, the panacea for the inherent issues within and predicament of primary PE. In effect, this PE-CPD programme with its limited duration and engagement with teachers, a heavy reliance on resources, and no planned follow-up support was not sufficiently different to forms of CPD described in the literature as ‘ineffective’; consequently, it could not hope to compensate for long-term systemic weaknesses such as inadequate primary PE-ITT. These weaknesses need to be addressed through a dual approach of ‘sufficient’ PE-ITT followed by ‘effective’ PE-CPD which engages teachers and their colleagues in long-term collaborative endeavours that support transformative practice

Estimation of HIV-1 incidence among five focal populations in Dehong, Yunnan: a hard hit area along a major drug trafficking route

<p>Abstract</p> <p>Background</p> <p>Since 1989 when the first 146 HIV positives in China were identified, Dehong Prefecture had been one of the areas hardest-hit by HIV in China. The local and national governments have put substantial financial resources into tackling the HIV epidemic in Dehong from 2004. The objective of this study was to track dynamic changes in HIV-1 prevalence and incidence among five focal populations in Dehong and to assess the impact of HIV prevention and control efforts.</p> <p>Methods</p> <p>Consecutive cross-sectional surveys conducted in five focal populations between 2004 and 2008. Specimens seropositive for HIV were tested with the BED IgG capture enzyme immunoassay to identify recent seroconversions (median, 155 days) using normalized optical density of 0.8 and adjustments.</p> <p>Results</p> <p>From 2004 to 2008, estimated annual HIV incidence among injecting drug users (IDUs) decreased significantly [from 15.0% (95% CI = 11.4%-18.5%) in 2004 to 4.3% (95% CI = 2.4%-6.2%) in 2008; trend test P < 0.0001]. The incidence among other focal populations, such as HIV discordant couples (varying from 5.5% to 4.7%), female sex workers (varying from 1.4% to 1.3%), pregnant women (0.1%), and pre-marital couples (0.2 to 0.1%) remained stable. Overall, the proportion of recent HIV-1 infections was higher among females than males (P < 0.0001).</p> <p>Conclusions</p> <p>The HIV epidemic in Dehong continued to expand during a five-year period but at a slowing rate among IDUs, and HIV incidence remains high among IDUs and discordant couples. Intensive prevention measures should target sub-groups at highest risk to further slow the epidemic and control the migration of HIV to other areas of China, and multivariate analysis is needed to explore which measures are more effective for different populations.</p

A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer

A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z/γ + X, in proton-tagged events from proton–proton collisions at √s = 13 TeV, recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. odelindependent upper limits on the visible production cross section of pp → pp + Z/γ + X are set