Stripe Fluctuations, Carriers, Spectroscopies, Transport, and BCS-BEC Crossover in the High-T_c Cuprates

The quasiparticles of the high-T_c cuprates are found to consist of: polaron-like "stripons" carrying charge, and associated primarily with large-U orbitals in stripe-like inhomogeneities; "quasielectrons" carrying charge and spin, and associated with hybridized small-U and large-U orbitals; and "svivons" carrying spin and lattice distortion. It is shown that this electronic structure leads to the systematic behavior of spectroscopic and transport properties of the cuprates. High-T_c pairing results from transitions between pair states of stripons and quasielectrons through the exchange of svivons. The cuprates fall in the regime of crossover between BCS and preformed-pairs Bose-Einstein condensation behaviors.Comment: Latex file, 8 pages (new version including a figure

Geographic variation in the treatment of non-ST-segment myocardial infarction in the English National Health Service: a cohort study

Objectives: To investigate geographic variation in guideline-indicated treatments for NSTEMI in the English National Health Service (NHS). Design: Cohort study using registry data from the Myocardial Ischaemia National Audit Project. Setting: All Clinical Commissioning Groups (CCGs) (n=211) in the English NHS. Participants: 357,228 patients with NSTEMI between 1st January, 2003 and 30th June, 2013. Main outcome measure: Proportion of eligible NSTEMI who received all eligible guideline-indicated treatments (optimal care) according to the date of guideline publication. Results: The proportion of NSTEMI who received optimal care was low (48,257/357,228; 13.5%) and varied between CCGs (median 12.8%, interquartile range 0.7 to 18.1%). The greatest geographic variation was for aldosterone antagonists (16.7%, 0.0 to 40.0%) and least for use of an electrocardiogram (96.7%, 92.5 to 98.7%). The highest rates of care were for acute aspirin (median 92.8%, interquartile range 88.6 to 97.1%), and aspirin (90.1%, 85.1 to 93.3%) and statins (86.4%, 82.3 to 91.2%) at hospital discharge. The lowest rates were for smoking cessation advice (median 11.6%, interquartile range 8.7 to 16.6%), dietary advice (32.4%, 23.9 to 41.7%) and the prescription of P2Y12 inhibitors (39.7%, 32.4 to 46.9%). After adjustment for case mix, nearly all (99.6%) of the variation was due to between hospitals differences (median 64.7%, interquartile range 57.4% to 70.0%; between hospital variance: 1.92, 95% confidence interval 1.51 to 2.44; interclass correlation 0.996, 0.976 to 0.999). Conclusions: Across the English NHS, the optimal use of guideline-indicated treatments for NSTEMI was low. Variation in the use of specific treatments for NSTEMI was mostly explained by between-hospital differences in care. Performance-based commissioning may increase the use of NSTEMI treatments and, therefore, reduce premature cardiovascular deaths

Critical appraisal skills of family physicians in Ontario, Canada

BACKGROUND: Our primary objective in this study was to measure family physicians' knowledge of the key elements that go into assessing the validity and interpreting the results in three different types of studies: i) a randomized controlled trial (RCT); ii) a study evaluating a diagnostic test; and iii) a systematic review (SR). Our secondary objectives were to determine the relationship between the above skills and age, gender, and type of practice. METHODS: We obtained a random sample of 1000 family physicians in Ontario from the College of Family Physicians of Canada database. These physicians were sent a questionnaire in the mail with follow-up mailings to non-responders at 3 and 8 weeks. The questionnaire was designed to measure knowledge and understanding of the basic concepts of critical appraisal skills. Based on the responses to the questions an Evidence Based Medicine (EBM) Knowledge Score was determined for each physician. RESULTS: A response rate of 30.2% was achieved. The respondents were younger and more likely to be recent graduates than the population of Ontario Family Physicians as a whole. This was an expected outcome. Just over 50% of respondents were able to answer questions concerning the critical appraisal of methods and the interpretation of results of research articles satisfactorily. The average score on the 12-point EBM Knowledge Scale was 6.4. The younger physicians scored higher than the older physicians, and academic physicians scored higher than community-based physicians. Scores of male and female physicians did not differ. CONCLUSIONS: We have shown that in a population of physicians which is younger than the general population of physicians, about 50% have reasonable knowledge regarding the critical appraisal of the methods and the interpretation of results of a research article. In general, younger physicians were more knowledgeable than were older physicians. EBM principles were felt to be important to the practice of medicine by 95% of respondents

Effects of melting, subduction-related metasomatism, and sub-solidus equilibration on the distribution of water contents in the mantle beneath the Rio Grande Rift

The distribution of water in the upper mantle plays a crucial role in the Earth's deep water cycle, magmatism, and plate tectonics. To better constrain how these large-scale geochemical systems operate, peridotite and pyroxenite mantle xenoliths from Kilbourne Hole (KH) and Rio Puerco (RP) along the Rio Grande Rift (NM, USA) were analyzed for water, and major and trace element contents. These xenoliths sample a lithosphere whose composition was influenced by subduction and rifting, and can be used to examine the effects of melting, metasomatism, and sub-solidus equilibration on the behavior of water. The first result is that in KH xenoliths, olivines underwent negligible H loss during xenolith ascent, i.e. preserved their mantle water contents. These olivine water contents are used to calculate mantle viscosities of 0.5–184 · 1021 Pa·s. These viscosity values are more than 40 times higher than those of the asthenosphere and show that KH peridotites represent samples from the lithosphere. The preservation of olivine water contents is exceptional for off-cratonic xenoliths, and the KH peridotites provide the first estimate of the average concentration of water in Phanerozoic continental mantle lithosphere at 81 ± 30 ppm H2O. The mantle lithosphere beneath the Rio Grande rift is nevertheless heterogeneous with water contents ranging from <0.5 to 120 ppm H2O in peridotites and from 227 to 400 ppm H2O in pyroxenites. A composite KH xenolith of a harzburgite cross-cut by a clinopyroxenite vein shows this heterogeneity at the cm scale. The second contribution of this study stems from the majority of the KH peridotites and two of the RP peridotites having major and trace elements that can be explained by partial melting without any need to invoke metasomatic processes. This allows to show that, prior to modelling the water content variation of each peridotite mineral during melting, a correction for sub-solidus equilibration has to be applied to the water contents of the minerals. Sub-solidus equilibration also provides an explanation for the discrepancy between the clinopyroxene/orthopyroxene ratio of water contents in natural peridotites worldwide and in laboratory experiments on water partitioning in peridotite minerals. Finally, the cryptically metasomatized peridotites, rare at KH and abundant at RP, as well as the pyroxenites, permit to decipher the origin and water contents of the metasomatic melts that affected the continental lithosphere beneath the Rio Grande Rift. Trace element modelling of the metasomatized KH and RP peridotites are consistent with metasomatism via melts that are of subduction origin. Melts in equilibrium with peridotites contain more water at RP (∼1 wt.% H2O) than at KH (∼0.5 wt.% H2O), although this did not result in a more water-rich mantle lithosphere at RP. Rio Puerco lies within the northern Rio Grande rift, proposed to have been affected by a flat slab subduction, which may explain the more hydrous and extensive metasomatism compared to the south, where KH is located

Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor

The proximity of superconductivity and antiferromagnetism in the phase diagram of iron arsenides, the apparently weak electron-phonon coupling and the "resonance peak" in the superconducting spin excitation spectrum have fostered the hypothesis of magnetically mediated Cooper pairing. However, since most theories of superconductivity are based on a pairing boson of sufficient spectral weight in the normal state, detailed knowledge of the spin excitation spectrum above the superconducting transition temperature Tc is required to assess the viability of this hypothesis. Using inelastic neutron scattering we have studied the spin excitations in optimally doped BaFe1.85Co0.15As2 (Tc = 25 K) over a wide range of temperatures and energies. We present the results in absolute units and find that the normal state spectrum carries a weight comparable to underdoped cuprates. In contrast to cuprates, however, the spectrum agrees well with predictions of the theory of nearly antiferromagnetic metals, without complications arising from a pseudogap or competing incommensurate spin-modulated phases. We also show that the temperature evolution of the resonance energy follows the superconducting energy gap, as expected from conventional Fermi-liquid approaches. Our observations point to a surprisingly simple theoretical description of the spin dynamics in the iron arsenides and provide a solid foundation for models of magnetically mediated superconductivity.Comment: 8 pages, 4 figures, and an animatio

Визначення понять «резидент» і «нерезидент»: проблеми теорії і практики

Досліджено практику застосування понять «резидент» та «нерезидент» у як в Україні так і окремих зарубіжних країнах, а також надано авторське бачення щодо визначення даних термінів. Автори статті визначають умови оподаткування операцій з нерезидентами з огляду на існуючі особливості правозастосовної діяльності і вно­сять окремі пропозиції щодо удосконалення процедури адміністрування податків, що стягуються з нерезидентів.Исследована практика применения понятий «резидент» и «нерезидент» как в Украине, так и отдельных зарубежных странах, а также предоставлено авторское виденье относительно определения данных терминов. Авторы статьи определяют условия налогообложения операций с нерезидентами, учитывая существующие особен­ности правоприменительной деятельности, вносят отдельные предложения относи­тельно усовершенствования процедуры администрирования налогов, которые удержи­ваются из нерезидентов.Іn this article practice of application of concepts «resident» and «non­resident» are explored both in Ukraine and some foreign countries, and granted the author’s view on the definition of these terms. The authors of the article determine the term of taxation of operations with non­residents, taking into account the existing features of legal activity and make some suggestions in relation to the improvement of procedure of administration of taxes which are tightened from non­residents

The 50s cliff: perceptuo-motor learning rates across the lifespan.

We recently found that older adults show reduced learning rates when learning a new pattern of coordinated rhythmic movement. The purpose of this study was to extend that finding by examining the performance of all ages across the lifespan from the 20 s through to the 80 s to determine how learning rates change with age. We tested whether adults could learn to produce a novel coordinated rhythmic movement (90° relative phase) in a visually guided unimanual task. We determined learning rates to quantify changes in learning with age and to determine at what ages the changes occur. We found, as before, that learning rates of participants in their 70 s and 80 s were half those of participants in their 20 s. We also found a gradual slow decline in learning rate with age until approximately age 50, when there was a sudden drop to a reduced learning rate for the 60 though 80 year olds. We discuss possible causes for the "50 s cliff" in perceptuo-motor learning rates and suggest that age related deficits in perception of complex motions may be the key to understanding this result