Our knowledge of the ground state of underdoped hole-doped cuprates has evolved considerably over the last few years. There is now compelling evidence that, inside the pseudogap phase, charge order ...breaks translational symmetry leading to a reconstructed Fermi surface made of small pockets. Quantum oscillations Doiron-Leyraud N, et al. (2007) Nature 447(7144):565-568, optical conductivity Mirzaei SI, et al. (2013) Proc Natl Acad Sci USA 110(15):5774-5778, and the validity of Wiedemann-Franz law Grissonnache G, et al. (2016) Phys Rev B 93:064513 point to a Fermi liquid regime at low temperature in the underdoped regime. However, the observation of a quadratic temperature dependence in the electrical resistivity at low temperatures, the hallmark of a Fermi liquid regime, is still missing. Here, we report magnetoresistance measurements in the magnetic-field-induced normal state of underdoped YBa
Cu
O
that are consistent with a T
resistivity extending down to 1.5 K. The magnitude of the T
coefficient, however, is much smaller than expected for a single pocket of the mass and size observed in quantum oscillations, implying that the reconstructed Fermi surface must consist of at least one additional pocket.
The dynamical downscaling method with a regional climate model (RCM) is widely used to assess the spatially detailed information about regional climate. However, the RCM result is considerably ...influenced by the systematic errors inherent to a general circulation model (GCM), which provides the initial and boundary conditions to the RCM. Such systematic errors sometimes lead to meaningless downscaled results. Many modified boundary dynamical downscaling (MBDDS) methods have been proposed to reduce the influences of the systematic errors of a GCM and extract meaningful signals for regional climate change. This study comprehensively reviews the MBDDS methods. The MBDDS methods partially modify the climate information projected by a GCM and use them as the boundary conditions of an RCM. The objectives of the methods are organized into two main objectives, that is, to obtain more reliable projections by correcting the biases in boundary conditions and to better understand the regional climate change mechanisms. To ensure comprehensive understanding of the MBDDS methods, this study attempts to interpret the errors included in the downscaled results using mathematical expressions, separating the GCM‐originated bias and RCM's own bias. Using this analysis, the MBDDS methods are classified based on the following questions: What effect is expected from the bias correction? Which of the climate change components projected by a GCM is considered when assessing the future climate change? The direction and issues that need to be addressed in the future for better understanding the regional climate change are also discussed.
Key Points
Dynamical downscaling methods are reviewed and reorganized based on their intents
Their objectives are to reduce biases and understand the mechanisms of regional climate change
The potential and future direction of modified boundary dynamical downscaling are discussed
In the quest to increase the critical temperature Tc of cuprate superconductors, it is essential to identify the factors that limit the strength of superconductivity. The upper critical field Hc2 is ...a fundamental measure of that strength, yet there is no agreement on its magnitude and doping dependence in cuprate superconductors. Here we show that the thermal conductivity can be used to directly detect Hc2 in the cuprates YBa2Cu3Oy, YBa2Cu4O8 and Tl2Ba2CuO6+δ, allowing us to map out Hc2 across the doping phase diagram. It exhibits two peaks, each located at a critical point where the Fermi surface of YBa2Cu3Oy is known to undergo a transformation. Below the higher critical point, the condensation energy, obtained directly from Hc2, suffers a sudden 20-fold collapse. This reveals that phase competition-associated with Fermi-surface reconstruction and charge-density-wave order-is a key limiting factor in the superconductivity of cuprates.
Maternal nutrition during pregnancy is one of the factors affecting the health of offspring. There are conflicting findings about the association between maternal vitamin D status and the development ...of allergic diseases in offspring. The purpose of this study is to evaluate the association between maternal vitamin D intake and the development of allergic diseases in offspring at 1 y of age. From an ongoing nationwide birth cohort study (the Japan Environment and Children’s Study), we obtained information on maternal vitamin D intake, determined by a food frequency questionnaire, and parent-reported physician-diagnosed allergic diseases in offspring at 1 y of age. From the full dataset of 103,062 pregnancies, we analyzed complete data for 82,592 mother–offspring pairs. The prevalence of physician-diagnosed asthma, food allergy, and atopic dermatitis in the children was 2.5%, 6.6%, and 4.3%, respectively. The mean (± standard deviation) maternal vitamin D intake was 4.7±4.7 μg/d, which is much lower than the recommended amount in Japan (7 μg/d). After adjustment for various covariates, the odds ratios were significantly higher for asthma in the 2nd quintile and for food allergies in the 3rd and 4th quintiles compared with the 1st quintile. However, there were no clear associations between maternal vitamin D intake and the development of allergic diseases in offspring at 1 y of age, even in a large nation-wide cohort study. Protective effects of vitamin D supplementation remain unclear.
Poisoning effects by various fuel impurities, including H
2S, CH
3SH, COS, Cl
2, and siloxane, to Ni–ScSZ cermet anodes have been analyzed and compared. Degradation of cell performance caused by ...these impurities was characterized by measuring cell voltage and anode polarization at a constant current density of 0.2 Acm
−
2
for humidified H
2 and CH
4 fuels. Poisoning for hydrogen-based fuels containing 5 ppm sulfur compounds, H
2S, CH
3SH, and COS, caused an initial cell voltage drop of about 15 mV at 1000 °C. The initial voltage drop was independent of the kind of sulfur compounds, whereas in the case of poisoning by CH
3SH, an additional gradual decrease in cell voltage was clearly detected after the initial voltage drop. Thermochemical calculation and FESEM-EDX analysis also indicated that the poisoning by Cl
2 caused the formation of nickel nano-particles on zirconia grains via NiCl
2 (g), while the poisoning by siloxane formed segregated silica (SiO
2) in porous cermet anodes.
High-temperature superconductivity in copper oxides occurs when the materials are chemically tuned to have a carrier concentration intermediate between their metallic state at high doping and their ...insulating state at zero doping. The underlying evolution of the electron system in the absence of superconductivity is still unclear, and a question of central importance is whether it involves any intermediate phase with broken symmetry. The Fermi surface of the electronic states in the underdoped 'YBCO' materials YBa2Cu3O(y) and YBa2Cu4O8 was recently shown to include small pockets, in contrast with the large cylinder that characterizes the overdoped regime, pointing to a topological change in the Fermi surface. Here we report the observation of a negative Hall resistance in the magnetic-field-induced normal state of YBa2Cu3O(y) and YBa2Cu4O8, which reveals that these pockets are electron-like rather than hole-like. We propose that these electron pockets most probably arise from a reconstruction of the Fermi surface caused by the onset of a density-wave phase, as is thought to occur in the electron-doped copper oxides near the onset of antiferromagnetic order. Comparison with materials of the La2CuO4 family that exhibit spin/charge density-wave order suggests that a Fermi surface reconstruction also occurs in those materials, pointing to a generic property of high-transition-temperature (T(c)) superconductors.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Despite the absence of experimental evidence, the weak scale supersymmetry remains as one of the best motivated and studied theoretical models beyond the Standard Model. This article summarises ...recent ATLAS results on inclusive searches for squarks and gluinos in R-parity conserving SUSY scenarios, including third generation squarks produced in the decay of gluinos. The searches involve final states containing jets, missing transverse momentum with and without a light lepton. No significance excess above the Standard Model prediction is observed and exclusion limits are set on 2-dimensional mass planes of benchmark signal models.
A charge excitation in a two-dimensional Mott insulator is strongly coupled with the surrounding spins, which is observed as magnetic-polaron formations of doped carriers and a magnon sideband in the ...Mott-gap transition spectrum. However, the dynamics related to the spin sector are difficult to measure. Here, we show that pump-probe reflection spectroscopy with seven-femtosecond laser pulses can detect the optically induced spin dynamics in Nd
CuO
, a typical cuprate Mott insulator. The bleaching signal at the Mott-gap transition is enhanced at ~18 fs. This time constant is attributable to the spin-relaxation time during magnetic-polaron formation, which is characterized by the exchange interaction. More importantly, ultrafast coherent oscillations appear in the time evolution of the reflectivity changes, and their frequencies (1400-2700 cm
) are equal to the probe energy measured from the Mott-gap transition peak. These oscillations can be interpreted as the interference between charge excitations with two magnons originating from charge-spin coupling.
Kimura's disease (KD) is known to be dominant among young Asian men, but it can also occur in middle- and advanced-aged people. The clinical characteristics of KD, especially by age, are not well ...known.
This study was performed to investigate the effects of age on the clinical characteristics of KD.
We conducted a case series study.
All case studies of patients diagnosed with KD were collected via a PubMed search of studies published until August 2018. The data were analyzed by age group.
In total, 215 studies were reviewed (238 patients; mean age of 36 years). The male:female ratio was 4:1 overall, 17:1 in patients aged <20 years, 4:1 in patients aged 20-39 years and 2:1 in patients aged ≥40 years (P = 0.01). The percentage of patients with pruritus was 15.4% overall, 3.8% in patients aged <20 years, 15.5% in patients aged 20-39 years and 21.7% in patients aged ≥40 years (P = 0.02). The time to diagnosis was 5.3 years overall, 3.2 years in patients aged <20 years, 4.7 years in patients aged 20-39 years and 7.1 years in patients aged ≥40 years (P < 0.01).
The proportion of female patients affected the incidence of pruritus, and the time to diagnosis increased as the patients' age increased. There were no significant age-related differences in region/race, complications, multiplicity, laterality, anatomical distribution, maximum size, eosinophil count, immunoglobulin E level, initial treatment, recurrence or outcomes. This may be useful information for the diagnosis of KD.
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