937 research outputs found
Order by disorder and spiral spin liquid in frustrated diamond lattice antiferromagnets
Frustration refers to competition between different interactions that cannot
be simultaneously satisfied, a familiar feature in many magnetic solids. Strong
frustration results in highly degenerate ground states, and a large suppression
of ordering by fluctuations. Key challenges in frustrated magnetism are
characterizing the fluctuating spin-liquid regime and determining the mechanism
of eventual order at lower temperature. Here, we study a model of a diamond
lattice antiferromagnet appropriate for numerous spinel materials. With
sufficiently strong frustration a massive ground state degeneracy develops
amongst spirals whose propagation wavevectors reside on a continuous
two-dimensional ``spiral surface'' in momentum space. We argue that an
important ordering mechanism is entropic splitting of the degenerate ground
states, an elusive phenomena called order-by-disorder. A broad ``spiral
spin-liquid'' regime emerges at higher temperatures, where the underlying
spiral surface can be directly revealed via spin correlations. We discuss the
agreement between these predictions and the well characterized spinel MnSc2S4
Gyroid-Structured 3D ZnO Networks Made by Atomic Layer Deposition
3D continuous ZnO morphologies with characteristic feature sizes on the 10 nm length scale are attractive for electronic device manufacture. However, their synthesis remains a challenge because of the low crystallization temperature of ZnO. Here, we report a method for the robust and reliable synthesis of fully crystalline 3D mesoporous ZnO networks by means of atomic layer deposition (ALD) of ZnO into a self-assembled block copolymer template. By carefully optimizing the processing conditions we are able to synthesize several-micrometer-thick layers of mesoporous ZnO networks with a strut width of 30 nm. Two 3D mesoporous morphologies are manufactured: a periodic gyroid structure and a random worm-like morphology. Exploiting the ALD property to conformally coat complex surfaces of high aspect ratio, the channel network of a 3D continuous channel network of a self-assembled block copolymer is replicated into ZnO. X-ray photoemission spectroscopy and x-ray diffraction measurements reveal that the chemical composition of the mesoporous structures is uniform and consists of wurtzite-ZnO throughout the film. Scanning electron microscopy reveals an average pore dimension of 30 nm. The potential of this material for a hybrid photovoltaic application is demonstrated by the manufacture of a poly(3-hexylthiophene)/ZnO solar cell
Subjective and objective evaluation of alertness and sleep quality in depressed patients
BACKGROUND: The reliability of the subjective statements reports on disturbed night sleep and alertness in the daytime was assessed by their correlation to the objective indicators in patients with mild deprsssion. METHOD: Among patients with depression, altogether 28 patients with insomnia were examined. Their answers to typical questions, as they are used during a psychiatric interview, were scored. In parallel, night sleep quality and alertness level in the daytime were objectively estimated by means of polygraphic recording. RESULTS: The subjective statements on the type of insomnia, the estimated time of falling asleep, frequent awakenings and occurrence of disturbing dreams seem to be unreliable. Similarly, the results were disappointing when the patients were asked about alertness disturbances in the daytime. An unexpected finding was the lack of any significant correlation to the scores obtained by means of Epworth's scale. Among the factors possibly influencing the patients' reports, age, sex, coffee intake and also chronic administration of sedatives or hypnotics showed a low correlation with the sleep and alertness indicators. CONCLUSION: The statistical evaluation indicated rather poor agreement between the subjective and objective items. The statistical evaluation suggested that anxiety and depression significantly influence reports on sleep quality and alertness disturbances in the daytime
A comparative study on long-term evoked auditory and visual potential responses between Schizophrenic patients and normal subjects
<p>Abstract</p> <p>Background</p> <p>The electrical signals measuring method is recommended to examine the relationship between neuronal activities and measure with the event related potentials (ERPs) during an auditory and a visual oddball paradigm between schizophrenic patients and normal subjects. The aim of this study is to discriminate the activation changes of different stimulations evoked by auditory and visual ERPs between schizophrenic patients and normal subjects.</p> <p>Methods</p> <p>Forty-three schizophrenic patients were selected as experimental group patients, and 40 healthy subjects with no medical history of any kind of psychiatric diseases, neurological diseases, or drug abuse, were recruited as a control group. Auditory and visual ERPs were studied with an oddball paradigm. All the data were analyzed by SPSS statistical software version 10.0.</p> <p>Results</p> <p>In the comparative study of auditory and visual ERPs between the schizophrenic and healthy patients, P300 amplitude at Fz, Cz, and Pz and N100, N200, and P200 latencies at Fz, Cz, and Pz were shown significantly different. The cognitive processing reflected by the auditory and the visual P300 latency to rare target stimuli was probably an indicator of the cognitive function in schizophrenic patients.</p> <p>Conclusions</p> <p>This study shows the methodology of application of auditory and visual oddball paradigm identifies task-relevant sources of activity and allows separation of regions that have different response properties. Our study indicates that there may be slowness of automatic cognitive processing and controlled cognitive processing of visual ERPs compared to auditory ERPs in schizophrenic patients. The activation changes of visual evoked potentials are more regionally specific than auditory evoked potentials.</p
Hegel and global politics: communitarianism or cosmopolitanism?
This article discusses Hegelâs views on global politics by relating them to the âcommunitarianism versus cosmopolitanismâ debate. I distinguish between three different theoretical positions and three different readings of Hegel, which I associate with the notions of âcommunitarianism,â âstrong cosmopolitanismâ and âweak cosmopolitanismâ respectively. Contrary to a commonly held view that Hegel is not a cosmopolitan thinker at all, in any sense of the term, I argue that he is best thought of as a weak cosmopolitan thinker rather than a communitarian or a strong cosmopolitan advocate of the idea of a world-state. In passing, the article refers to the relationship which exists between Hegelâs ideas and those of three Twentieth Century theorists who might be associated with these theoretical positions and these different readings of Hegel, namely, Carl Schmitt, Alexandre KojĂšve and Jurgen Habermas. The article also refers to the methodological problems which are confronted by readers of Hegelâs writings who wish to apply his ideas to the problems of global politics today. Here I refer to a distinction which I have made elsewhere between different kinds of reading, namely the interpretation, appropriation and the reconstruction of texts, which is especially relevant for readers of the works of Hegel
Outcomes of surgical treatment for upper urinary tract transitional cell carcinoma: Comparison of retroperitoneoscopic and open nephroureterectomy
<p>Abstract</p> <p>Objectives</p> <p>To determine the surgical and oncologic outcomes in patients who underwent retroperitoneoscopic nephroureterectomy (RNU) in comparison to standard open nephroureterectomy (ONU) for upper urinary tract transitional cell carcinoma (TCC).</p> <p>Patients and methods</p> <p>From April 2001 to January 2007, 60 total nephroureterectomy were performed for upper tract TCC at Siriraj Hospital. Of the 60 patients, thirty-one were treated with RNU and open bladder cuff excision, and twenty-nine with ONU. Our data were reviewed and analyzed retrospectively. The recorded data included sex, age, history of bladder cancer, type of surgery, tumor characteristics, postoperative course, disease recurrence and progression.</p> <p>Results</p> <p>The mean operative time was longer in the RNU group than in the ONU group (258.8 versus 190.6 min; p = 0. < 001). On the other hand, the mean blood loss and the dose of parenteral analgesia (morphine sulphate) were lower in the RNU group (289.3 versus 313.7 ml and 2.05 versus 6.72 mg; p = 0.868 and p = 0.018, respectively). There were two complications in each group. No significant difference in p stage and grade in both-groups (p = 0.951, p = 0.077). One patient with RNU had lymph node involvement, three in ONU. Mean follow up was 26.4 months (range 3â72) for RNU and 27.9 months (range 3â63) for ONU. No port metastasis occurred during follow up in RNU group. Tumor recurrence developed in 11 patients (bladder recurrence in 9 patients, local recurrence in 2 patients) in the RNU group and 14 patients (bladder recurrence in 13 patients, local recurrence in 1 patient) in the ONU group. No significant difference was detected in the tumor recurrence rate between the two procedures (p = 0.2716). Distant metastases developed in 3 patients (9.7%) after RNU and 2 patients (6.9%) after ONU. The 2 year disease specific survival rate after RNU and ONU was 86.3% and 92.5%, respectively (p = 0.8227).</p> <p>Conclusion</p> <p>Retroperitoneoscopic nephroureterectomy is less invasive than open surgery and is an oncological feasible operation. Thus, the results of our study supported the continued development of laparoscopic technique in the management of upper tract TCC.</p
Morphology and photoluminescence study of titania nanoparticles
Titania nanoparticles are prepared by solâgel chemistry with a poly(ethylene oxide) methyl ether methacrylate-block-poly(dimethylsiloxane)-block-poly(ethylene oxide) methyl ether methacrylate triblock copolymer acting as the templating agent. The solâgel componentsâhydrochloric acid, titanium tetraisopropoxide, and triblock copolymerâare varied to investigate their effect on the resulting titania morphology. An increased titania precursor or polymer content yields smaller primary titania structures. Microbeam grazing incidence small-angle X-ray scattering measurements, which are analyzed with a unified fit model, reveal information about the titania structure sizes. These small structures could not be observed via the used microscopy techniques. The interplay among the solâgel components via our triblock copolymer results in different sized titania nanoparticles with higher packing densities. Smaller sized titania particles, (âŒ13â20 nm in diameter) in the range of exciton diffusion length, are formed by 2% by weight polymer and show good crystallinity with less surface defects and high oxygen vacancies
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factorsâthe summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6â58·8) of global deaths and 41·2% (39·8â42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of âs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTâ„20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60â€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2â€{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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