132,976 research outputs found
Metal-insulator (fermion-boson)-crossover origin of pseudogap phase of cuprates I: anomalous heat conductivity, insulator resistivity boundary, nonlinear entropy
Among all experimental observations of cuprate physics, the
metal-insulator-crossover (MIC), seen in the pseudogap (PG) region of the
temperature-doping phase diagram of copper-oxides under a strong magnetic
field, when the superconductivity is suppressed, is most likely the most
intriguing one. Since it was expected that the PG-normal state for these
materials, as for conventional superconductors, is conducting. This MIC,
revealed in such phenomena as heat conductivity downturn, anomalous Lorentz
ratio, insulator resistivity boundary, nonlinear entropy, resistivity
temperature upturn, insulating ground state, nematicity- and stripe-phases and
Fermi pockets, unambiguously indicates on the insulating normal state, from
which the high-temperature superconductivity (HTS) appears. In the present work
(article I), we discuss the MIC phenomena mentioned in the title of article.
The second work (article II) will be devoted to discussion of other listed
above MIC phenomena and also to interpretation of the recent observations in
the hidden magnetic order and scanning tunneling microscopy (STM) experiments
spin and charge fluctuations as the intra PG and HTS pair ones. We find that
all these MIC (called in the literature as non-Fermi liquid) phenomena can be
obtained within the Coulomb single boson and single fermion two liquid model,
which we recently developed, and the MIC is a crossover of single fermions into
those of single bosons. We show that this MIC originates from bosons of Coulomb
two liquid model and fermions, whose origin is these bosons. At an increase of
doping up to critical value or temperature up to PG boundary temperature, the
boson system undegoes bosonic insulator - bosonic metal - fermionic metal
transitions.Comment: 13 pages, 3 figure
Report on objective ride quality evaluation
The correlation of absorbed power as an objective ride measure to the subjective evaluation for the bus data was investigated. For some individual bus rides the correlations were poor, but when a sufficient number of rides was used to give reasonable sample base, an excellent correlation was obtained. The following logarithmical function was derived: S = 1.7245 1n (39.6849 AP), where S = one subjective rating of the ride; and AP = the absorbed power in watts. A six-degree-of-freedom method developed for aircraft data was completed. Preliminary correlation of absorbed power with ISO standards further enhances the bus ride and absorbed power correlation numbers since the AP's obtained are of the same order of magnitude for both correlations. While it would then appear that one could just use ISO standards, there is no way to add the effect of three degrees of freedom. The absorbed power provides a method of adding the effects due to the three major directions plus the pitch and roll
Rich variety of defects in ZnO via an attractive interaction between O-vacancies and Zn-interstitials
As the concentration of intrinsic defects becomes sufficiently high in
O-deficient ZnO, interactions between defects lead to a significant reduction
in their formation energies. We show that the formation of both O-vacancies and
Zn-interstitials becomes significantly enhanced by a strong attractive
interaction between them, making these defects an important source of n-type
conductivity in ZnO.Comment: 12 pages, 4 figure
The Mechanical Impact of the Tibetan Plateau on the Seasonal Evolution of the South Asian Monsoon
The impact of the Tibetan Plateau on the South Asian monsoon is examined using a hierarchy of atmospheric general circulation models. During the premonsoon season and monsoon onset (April–June), when westerly winds over the Southern Tibetan Plateau are still strong, the Tibetan Plateau triggers early monsoon rainfall downstream, particularly over the Bay of Bengal and South China. The downstream moist convection is accompanied by strong monsoonal low-level winds. In experiments where the Tibetan Plateau is removed, monsoon onset occurs about a month later, but the monsoon circulation becomes progressively stronger and reaches comparable strength during the mature phase. During the mature and decaying phase of monsoon (July–September), when westerly winds over the Southern Tibetan Plateau almost disappear, monsoon circulation strength is not much affected by the presence of the Tibetan Plateau.
A dry dynamical core with east–west-oriented narrow mountains in the subtropics consistently simulates downstream convergence with background zonal westerlies over the mountain. In a moist atmosphere, the mechanically driven downstream convergence is expected to be associated with significant moisture convergence. The authors speculate that the mechanically driven downstream convergence in the presence of the Tibetan Plateau is responsible for zonally asymmetric monsoon onset, particularly over the Bay of Bengal and South China
Palliative stenting for oesophagogastric cancer: tumour and host factors and prognosis
Objectives: Palliative self-expandable metallic stent (SEMS) insertion is common in patients not suitable for resection of oesophagogastric (OG) cancer. Factors which may determine survival, however, are not clear. The present study examined the relationship between tumour and host factors, including the systemic inflammatory response and survival of patients undergoing palliative SEMS insertion.
Methods: Patients with a diagnosis of OG cancer who were considered suitable for palliative SEMS only without systemic therapy were identified. Patient characteristics including Eastern Cooperative Oncology Group performance status, radiological stage and modified Glasgow Prognostic Score (mGPS: 0—C-reactive protein (CRP) ≤10 mg/L; 1—CRP >10 mg/L; 2—CRP >10 mg/L; albumin <35 g/L) were recorded prospectively. The relationship between such characteristics and 3-month survival was examined.
Results: 203 patients were included in the final analysis. All patients died during follow-up, with median survival from diagnosis 75 days (IQR 47–157). 78% of patients were systemically inflamed (mGPS >1). On multivariate analysis, only poor performance status (HR 1.23, p=0.025), metastatic disease (HR 2.27, p<0.001) and mGPS (HR 1.25, p=0.021) were associated with shorter survival. The combination of performance status and mGPS stratified 3-month survival of patients without metastatic disease from 88% to 20% (p<0.001) and patients with metastases from 43% to 6% (p=0.059). Similar results were observed when analysis was restricted to patients with oesophageal and junctional cancer (M0: 83%–20%, p=0.008; M1: 33%–8%, p=0.082).
Conclusion: Performance status, metastatic disease and mGPS are independent predictors of survival in patients with OG cancer undergoing palliative SEMS insertion. These routinely available markers provide a rational system on which to base decisions regarding prognosis and treatment
Analytic Expressions for Geometric Measure of Three Qubit States
A new method is developed to derive an algebraic equations for the geometric
measure of entanglement of three qubit pure states. The equations are derived
explicitly and solved in cases of most interest. These equations allow oneself
to derive the analytic expressions of the geometric entanglement measure in the
wide range of the three qubit systems, including the general class of W-states
and states which are symmetric under permutation of two qubits. The nearest
separable states are not necessarily unique and highly entangled states are
surrounded by the one-parametric set of equally distant separable states. A
possibility for the physical applications of the various three qubit states to
quantum teleportation and superdense coding is suggested from the aspect of the
entanglement.Comment: 6 pages, no figure, PRA versio
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