1,598 research outputs found
Quantum theory of light diffraction
At present, the theory of light diffraction only has the simple wave-optical
approach. In this paper, we study light diffraction with the approach of
relativistic quantum theory. We find that the slit length, slit width, slit
thickness and wave-length of light have affected to the diffraction intensity
and form of diffraction pattern. However, the effect of slit thickness on the
diffraction pattern can not be explained by wave-optical approach, and it can
be explained in quantum theory. We compare the theoretical results with single
and multiple slits experiment data, and find the theoretical results are
accordance with the experiment data. Otherwise, we give some theory prediction.
We think all the new prediction will be tested by the light diffraction
experiment.Comment: 10 page
Approximability of the Eight-Vertex Model
We initiate a study of the classification of approximation complexity of the eight-vertex model defined over 4-regular graphs. The eight-vertex model, together with its special case the six-vertex model, is one of the most extensively studied models in statistical physics, and can be stated as a problem of counting weighted orientations in graph theory. Our result concerns the approximability of the partition function on all 4-regular graphs, classified according to the parameters of the model. Our complexity results conform to the phase transition phenomenon from physics.
We introduce a quantum decomposition of the eight-vertex model and prove a set of closure properties in various regions of the parameter space. Furthermore, we show that there are extra closure properties on 4-regular planar graphs. These regions of the parameter space are concordant with the phase transition threshold. Using these closure properties, we derive polynomial time approximation algorithms via Markov chain Monte Carlo. We also show that the eight-vertex model is NP-hard to approximate on the other side of the phase transition threshold
Expression of Wnt and NCX1 and its correlation with cardiomyocyte apoptosis in mouse with myocardial hypertrophy
AbstractObjectiveTo study the correlation between expression of Wnt and NCX1 and cardiomyocyte apoptosis in mouse with myocardial hypertrophy.MethodsC57B/16 male mice were given the subcutaneous injection of 1Â mg/kg isoprenaline to build the myocardial hypertrophy model. After 14Â d of model building, mice were executed by cervical vertebra luxation. The ratio of heart weight/body weight (HW/BW) and heart weight/tibia length (HW/TL) was observed and proved using HE staining that detected the size of cardiomyocytes. 40 male C57B/16 mice were randomly divided into the sham group (normal saline) and model group (isoprenaline), with 20 mice in each group. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was applied to detect the cardiomyocyte apoptosis; while Western blot and immunohistochemistry were employed to detect the expression of Wnt and NCX1. Meanwhile, the correlation between these two proteins and cardiomyocyte apoptosis was explored.ResultsCompared with the sham group, the ratio of HW/BW and HW/TL was increased in the model group, as well as the bigger and hypertrophied cardiomyocytes, decreased number and increased apoptosis of cardiomyocytes, and increased positive expression of Wnt3a, Wnt5a and NCX1 in the cardiac muscle tissue. Besides, there was positive correlation between the expression of Wnt and NCX1 and the cardiomyocyte apoptosis.ConclusionThe expression of Wnt3a, Wnt5a and NCX1 in mouse with myocardial hypertrophy is increased and positively correlated with the cardiomyocyte apoptosis
Poststroke depression and risk of stroke recurrence and mortality:protocol of a meta-analysis and systematic review
Introduction A number of observational studies have indicated that poststroke depression could increase the risk of stroke outcomes. There is a meta-analysis indicating that poststroke depression is a risk factor of all-cause mortality. This paper reports the protocol for a systematic review and meta-analysis to clarify the associations of poststroke depression with stroke recurrence and mortality in order to determine whether poststroke depression is a predictor of stroke outcomes according to data extracted from relevant observational studies.Methods and analysis MEDLINE, Web of Science databases, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews will be used to conduct the search. Published studies written in English will be included. The risk of bias for the studies included in the systematic review or meta-analysis will be assessed by the Newcastle–Ottawa Quality Assessment Scale. HRs for stroke recurrence and mortality with 95% CIs will be included as primary outcomes. Subgroup analyses and meta-regression will be performed.Ethics and dissemination Ethics approval will not be needed because the data used in this systematic review will be extracted from published studies. The results of the systematic review focusing on whether depression after stroke is a predictor for stroke recurrence and mortality will be disseminated by publication in a peer-reviewed journal.PROSPERO registration number CRD42018107944
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