479 research outputs found

    Phase transitions and quantum effects in anharmonic crystals

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    The most important recent results in the theory of phase transitions and quantum effects in quantum anharmonic crystals are presented and discussed. In particular, necessary and sufficient conditions for a phase transition to occur at some temperature are given in the form of simple inequalities involving the interaction strength and the parameters describing a single oscillator. The main characteristic feature of the theory is that both mentioned phenomena are described in one and the same setting, in which thermodynamic phases of the model appear as probability measures on path spaces. Then the possibility of a phase transition to occur is related to the existence of multiple phases at the same values of the relevant parameters. Other definitions of phase transitions, based on the non-differentiability of the free energy density and on the appearance of ordering, are also discussed

    Are black holes over-produced during preheating?

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    We provide a simple but robust argument that primordial black hole (PBH) production generically does {\em not} exceed astrophysical bounds during the resonant preheating phase after inflation. This conclusion is supported by fully nonlinear lattice simulations of various models in two and three dimensions which include rescattering but neglect metric perturbations. We examine the degree to which preheating amplifies density perturbations at the Hubble scale and show that at the end of the parametric resonance, power spectra are universal, with no memory of the power spectrum at the end of inflation. In addition we show how the probability distribution of density perturbations changes from exponential on very small scales to Gaussian when smoothed over the Hubble scale -- the crucial length for studies of primordial black hole formation -- hence justifying the standard assumption of Gaussianity.Comment: 12 pages, 8 figures, revtex, added references for section

    A New On-Land Seismogenic Structure Source Database from the Taiwan Earthquake Model (TEM) Project for Seismic Hazard Analysis of Taiwan

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    Taiwan is located at an active plate boundary and prone to earthquake hazards. To evaluate the island’s seismic risk, the Taiwan Earthquake Model (TEM) project, supported by the Ministry of Sciences and Technology, evaluates earthquake hazard, risk, and related social and economic impact models for Taiwan through multidisciplinary collaboration. One of the major tasks of TEM is to construct a complete and updated seismogenic structure database for Taiwan to assess future seismic hazards. Toward this end, we have combined information from pre-existing databases and data obtained from new analyses to build an updated and digitized three-dimensional seismogenic structure map for Taiwan. Thirty-eight on-land active seismogenic structures are identified. For detailed information of individual structures such as their long-term slip rates and potential recurrence intervals, we collected data from existing publications, as well as calculated from results of our own field surveys and investigations. We hope this updated database would become a significant constraint for seismic hazard assessment calculations in Taiwan, and would provide important information for engineers and hazard mitigation agencies

    Transverse optical binding for a dual dipolar dielectric nanoparticle dimer

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    Funding: This work was supported by the National Key R&D Program of China (2017YFA0303400) andPostgraduate Education Reform Project of Tongji University (2018GH103). KD acknowledges support of the UK Engineering and Physical Sciences Research Council (grant EP/P030017/1).The physical origins of transverse optical binding force and torque beyond Rayleigh approximation have not been clearly expressed to date. Here, we present analytical expressions of the force and torque for a dual dipolar dielectric dimer illuminated by a plane wave propagating perpendicularly to the dimer axis. Using this analytical model, we explore the role of the hybridized electric dipolar, magnetic dipolar, and electric-magnetic dipolar coupling interactions in the total force and torque on the particles. We find significant departures from the predictions of the Rayleigh approximation, especially for high-refractive index particles, where the force is dominated by the magnetic interaction. This results in the enhancement of the dimer stability by 1 to 4 orders of magnitude compared to the predictions of the Rayleigh approximation. For the torque, this is dominated by the coupling interaction and increases by an order of magnitude. Our results will help to guide future experimental work in the light-controlled self-assembly of high-refractive-index dielectric particles.PostprintPeer reviewe

    Black hole production in tachyonic preheating

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    We present fully non-linear simulations of a self-interacting scalar field in the early universe undergoing tachyonic preheating. We find that density perturbations on sub-horizon scales which are amplified by tachyonic instability maintain long range correlations even during the succeeding parametric resonance, in contrast to the standard models of preheating dominated by parametric resonance. As a result the final spectrum exhibits memory and is not universal in shape. We find that throughout the subsequent era of parametric resonance the equation of state of the universe is almost dust-like, hence the Jeans wavelength is much smaller than the horizon scale. If our 2D simulations are accurate reflections of the situation in 3D, then there are wide regions of parameter space ruled out by over-production of black holes. It is likely however that realistic parameter values, consistent with COBE/WMAP normalisation, are safetly outside this black hole over-production region.Comment: 6pages, 7figures, figures correcte

    IS INTERPROFESSIONAL PRACTICE (IPP) FOCUSED ON MEDICATION SAFETY FEASIBLE IN INDONESIA? A QUALITATIVE STUDY

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    This paper explores facilitators for and barriers to the implementation of IPP focusing on medication safety in a public hospital in Bali, Indonesia. Qualitative methods involved interviews with stakeholders from a university and a hospital and focus group discussions with healthcare professionals in the hospital. Semi-structured questions were developed as a guide for the interviews and discussions. All interviews and discussions were recorded. The six steps of Braun and Clarke’s thematic analysis methodology were implemented in determining the themes. The Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist was employed in reporting of findings. Participants indicated that support from the government and perceived benefits of IPP were facilitators for IPP. However, the participants mostly mentioned the barriers of IPP including lack of competencies for IPP and lack of understanding of the role of other healthcare professionals as barriers to the implementation of IPP. This showed that these were the barriers identified to the implementation of IPP in the study hospital. Despite the fact that participants were supportive of IPP, the participants identified some barriers to the implementation of IPP in the study hospital. The implementation requires support of the government, professional organisations, and stakeholders at the university and hospital levels

    Multimorbidity in bipolar disorder and under-treatment of cardiovascular disease: a cross sectional study

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    Background: Individuals with serious mental disorders experience poor physical health, especially increased rates of cardiometabolic morbidity and premature morbidity. Recent evidence suggests that individuals with schizophrenia have numerous comorbid physical conditions which may be under-recorded and under-treated but to date very few studies have explored this issue for bipolar disorder. Methods:We conducted a cross-sectional analysis of a dataset of 1,751,841 registered patients within 314 primary-care practices in Scotland, U.K. Bipolar disorder was identified using Read Codes recorded within electronic medical records. Data on 32 common chronic physical conditions were also assessed. Potential prescribing inequalities were evaluated by analyzing prescribing data for coronary heart disease (CHD) and hypertension. Results: Compared to controls, individuals with bipolar disorder were significantly less likely to have no recorded physical conditions (OR 0.59, 95% CI 0.54-0.63) and significantly more likely to have one physical condition (OR 1.27, 95% CI 1.16-1.39), two physical conditions (OR 1.45, 95% CI 1.30-1.62) and three or more physical conditions (OR 1.44, 95% CI 1.30-1.64). People with bipolar disorder also had higher rates of thyroid disorders, chronic kidney disease, chronic pain, chronic obstructive airways disease and diabetes but, surprisingly, lower recorded rates of hypertension and atrial fibrillation. People with bipolar disorder and comorbid CHD or hypertension were significantly more likely to be prescribed no antihypertensive or cholesterol-lowering medications compared to controls, and bipolar individuals with CHD or hypertension were significantly less likely to be on 2 or more antihypertensive agents. Conclusions: Individuals with bipolar disorder are similar to individuals with schizophrenia in having a wide range of comorbid and multiple physical health conditions. They are also less likely than controls to have a primary-care record of cardiovascular conditions such as hypertension and atrial fibrillation. Those with a recorded diagnosis of CHD or hypertension were less likely to be treated with cardiovascular medications and were treated less intensively. This study highlights the high physical healthcare needs of people with bipolar disorder, and provides evidence for a systematic under-recognition and under-treatment of cardiovascular disease in this group

    Carbon-emcoating architecture boosts lithium storage of Nb2O5

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    Intercalation transition metal oxides (ITMO) have attracted great attention as lithium-ion battery negative electrodes due to high operation safety, high capacity and rapid ion intercalation. However, the intrinsic low electron conductivity plagues the lifetime and cell performance of the ITMO negative electrode. Here we design a new carbon-emcoating architecture through single CO2 activation treatment as demonstrated by the Nb2O5/C nanohybrid. Triple structure engineering of the carbon-emcoating Nb2O5/C nanohybrid is achieved in terms of porosity, composition, and crystallographic phase. The carbon-embedding Nb2O5/C nanohybrids show superior cycling and rate performance compared with the conventional carbon coating, with reversible capacity of 387 mA h g−1 at 0.2 C and 92% of capacity retained after 500 cycles at 1 C. Differential electrochemical mass spectrometry (DEMS) indicates that the carbon emcoated Nb2O5 nanohybrids present less gas evolution than commercial lithium titanate oxide during cycling. The unique carbon-emcoating technique can be universally applied to other ITMO negative electrodes to achieve high electrochemical performance

    Inter-Allelic Prion Propagation Reveals Conformational Relationships among a Multitude of [PSI] Strains

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    Immense diversity of prion strains is observed, but its underlying mechanism is less clear. Three [PSI] prion strains—named VH, VK, and VL—were previously isolated in the wild-type yeast genetic background. Here we report the generation and characterization of eight new [PSI] isolates, obtained by propagating the wild-type strains with Sup35 proteins containing single amino-acid alterations. The VH strain splits into two distinct strains when propagated in each of the three genetic backgrounds, harboring respectively single mutations of N21L, R28P, and Gi47 (i.e. insertion of a glycine residue at position 47) on the Sup35 N-terminal prion-forming segment. The six new strains exhibit complex inter-conversion patterns, and one of them continuously mutates into another. However, when they are introduced back into the wild-type background, all 6 strains revert to the VH strain. We obtain two more [PSI] isolates by propagating VK and VL with the Gi47 and N21L backgrounds, respectively. The two isolates do not transmit to other mutant backgrounds but revert to their parental strains in the wild-type background. Our data indicate that a large number of [PSI] strains can be built on three basic Sup35 amyloid structures. It is proposed that the three basic structures differ by chain folding topologies, and sub-strains with the same topology differ in distinct ways by local structural adjustments. This “large number of variations on a small number of basic themes” may also be operative in generating strain diversities in other prion elements. It thus suggests a possible general scheme to classify a multitude of prion strains
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