77,165 research outputs found
Strong earthquakes, novae and cosmic ray environment
Observations about the relationship between seismic activity and astronomical phenomena are discussed. First, after investigating the seismic data (magnitude 7.0 and over) with the method of superposed epochs it is found that world seismicity evidently increased after the occurring of novae with apparent magnitude brighter than 2.2. Second, a great many earthquakes of magnitude 7.0 and over occurred in the 13th month after two of the largest ground level solar cosmic ray events (GLEs). The causes of three high level phenomena of global seismic activity in 1918-1965 can be related to these, and it is suggested that according to the information of large GLE or bright nova predictions of the times of global intense seismic activity can be made
Using the information of cosmic rays to predict influence epidemic
A correlation between the incidence of influenza pandemics and increased cosmic ray activity is made. A correlation is also made between the occurrence of these pandemics and the appearance of bright novae, e.g., Nova Eta Car. Four indices based on increased cosmic ray activity and novae are proposed to predict future influenza pandemics and viral antigenic shifts
Magnetoresistance of atomic-scale electromigrated nickel nanocontacts
We report measurements of the electron transport through atomic-scale
constrictions and tunnel junctions between ferromagnetic electrodes. Structures
are fabricated using a combination of e-beam lithography and controlled
electromigration. Sample geometries are chosen to allow independent control of
electrode bulk magnetizations. As junction size is decreased to the single
channel limit, conventional anisotropic magnetoresistance (AMR) increases in
magnitude, approaching the size expected for tunneling magnetoresistance (TMR)
upon tunnel junction formation. Significant mesoscopic variations are seen in
the magnitude and sign of the magnetoresistance, and no evidence is found of
large ballistic magnetoresistance effects.Comment: 3 pages, 3 figure
Low Threshold Parametric Decay Back Scattering Instability in Tokamak ECRH Experiments
The experimental conditions leading to substantial reduction of
backscattering decay instability threshold in ECRH experiments in toroidal
devices are analyzed. It is shown that drastic decrease of threshold is
provided by non monotonic behavior of plasma density in the vicinity of
magnetic island and poloidal magnetic field inhomogeneity making possible
localization of ion Bernstein decay waves. The corresponding ion Bernstein wave
gain and the parametric decay instability pump power threshold is calculated.Comment: 7 pages, 4 figure
Doppler Radar Vital Signs Detection Method Based on Higher Order Cyclostationary
Due to the non-contact nature, using Doppler radar sensors to detect vital signs such as heart and respiration rates of a human subject is getting more and more attention. However, the related detection-method research meets lots of challenges due to electromagnetic interferences, clutter and random motion interferences. In this paper, a novel third-order cyclic cummulant (TOCC) detection method, which is insensitive to Gaussian interference and non-cyclic signals, is proposed to investigate the heart and respiration rate based on continuous wave Doppler radars. The k-th order cyclostationary properties of the radar signal with hidden periodicities and random motions are analyzed. The third-order cyclostationary detection theory of the heart and respiration rate is studied. Experimental results show that the third-order cyclostationary approach has better estimation accuracy for detecting the vital signs from the received radar signal under low SNR, strong clutter noise and random motion interferences
OPERA superluminal neutrinos and Kinematics in Finsler spacetime
The OPERA collaboration recently reported that muon neutrinos could be
superluminal. More recently, Cohen and Glashow pointed that such superluminal
neutrinos would be suppressed since they lose their energies rapidly via
bremsstrahlung. In this Letter, we propose that Finslerian nature of spacetime
could account for the superluminal phenomena of particles. The Finsler
spacetime permits the existence of superluminal behavior of particles while the
casuality still holds. A new dispersion relation is obtained in a class of
Finsler spacetime. It is shown that the superluminal speed is linearly
dependent on the energy per unit mass of the particle. We find that such a
superluminal speed formula is consistent with data of OPERA, MINOS and
Fermilab-1979 neutrino experiments as well as observations on neutrinos from
SN1987a.Comment: 10 pages, 2 figures. Viewpoints of Finslerian special relativity on
OPERA superluminal neutrino
Thermal effects in InGaAs/AlAsSb quantum-cascade lasers
A quantum-cascade laser (QCL) thermal model is presented. On the basis of a finite-difference approach, the model is used in conjunction with a self-consistent carrier transport model to calculate the temperature distribution in a near-infrared InGaAs/AlAsSb QCL. The presented model is used to investigate the effects of driving conditions and device geometries on the active-region temperature, which has a major influence on the device performance. A buried heterostructure combined with epilayer-down mounting is found to offer the best performance compared with alternative structures and has thermal time constants up to eight times smaller. The presented model provides a valuable tool for understanding the thermal dynamics inside a QCL and will help to improve operating temperatures
Interaction between Mean Arterial Pressure and HbA1c in Prediction of Cardiovascular Disease Hospitalisation: A Population-Based Case-Control Study
Objective. To explore the relationship between mean arterial pressure (MAP), HbA1c, and cardiovascular (CV) hospitalisation risk in type 2 diabetes.
Design. Population-based case-control study.
Settings. Primary and secondary care level in Cambridgeshire, United Kingdom. Participants. 588 patients with type 2 diabetes from 18 English general practices recording a CV hospitalisation in 2009–2011 were included. Risk-set sampling was used to select 2920 gender, age, and practice matched control type 2 diabetes patients.
Main Outcome Measure. Conditional logistic regression was used to explore further dose-response relationships between MAP, HbA1c, and CV hospitalisation risk.
Results. The relationship between MAP and CV hospitalisation was nonlinear ( for linearity test). The MAP associated with the lowest CV hospitalisation risk was 97 (95% CI: 93–101) mmHg. An interaction between MAP and HbA1c for increased risk of cardiovascular hospitalisation was observed among those with HbA1c < 7% (53 mmol/mol) and MAP < 97 mmHg.
Conclusions. In type 2 diabetes, MAP is a good predictor of CV hospitalisation risk. CV hospitalisation is lowest with a MAP between 93 and 101 mmHg. CV hospitalisation was particularly high among those with both a low MAP and a lower HbA1c
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