In this paper, we provide some new necessary and sufficient conditions for generalized diagonally dominant matrices and also obtain some criteria for nongeneralized dominant matrices.
AIM To investigate the relationship of inferior wall ischemia on myocardial perfusion imaging in patients with nondominant right coronary artery anatomy.METHODS This was a retrospective observational analysis of conse...AIM To investigate the relationship of inferior wall ischemia on myocardial perfusion imaging in patients with nondominant right coronary artery anatomy.METHODS This was a retrospective observational analysis of consecutive patients who presented to the emergency department with primary complaint of chest pain.Only patients who underwent single photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI)were included.Patients who showed a reversible defect on SPECT MPI and had coronary angiography during the same hospitalization was analyzed.Patients with prior history of coronary artery disease(CAD)including history of percutaneous coronary intervention and coronary artery bypass graft surgerys were excluded.True positive and false positive results were identified on the basis of hemodynamically significant CAD on coronary angiography,in the same territory as identified on SPECT MPI.Coronary artery dominance was determined on coronary angiography.Patients were divided into group 1 and group 2.Group1 included patients with non-dominant right coronary artery(RCA)(left dominant and codominant).Group2 included patients with dominant RCA anatomy.Demographics,baseline characteristics and positive predictive value(PPV)were analyzed for the two groups.RESULTS The mean age of the study cohort was 57.6 years.Sixtyone point seven percent of the patients were males.The prevalence of self-reported diabetes mellitus,hypertension and dyslipidemia was 36%,71.9%and 53.9%respectively.A comparison of baseline characteristics between the two groups showed that patients with a non-dominant RCA were more likely to be men.For inferior wall ischemia on SPECT MPI,patients in study group 2 had a significantly higher PPV,32/42(76.1%),compared to patients in group 1,in which only 3 out of the 29 patients(10.3%)had true positive results(P value<0.001 Z test).The difference remained statistically significant even when only patients with left dominant coronary system(without co-dominant)were compared to patients with right dominant system(32/40,76.1%in right dominant group,3/19,15.8%in left dominant group,P value<0.001 Z test).There was no significant difference in mean hospital stay,re-hospitalization,and in-hospital mortality between the two groups.CONCLUSION The positive predictive value of SPECT MPI for inferior wall ischemia is affected by coronary artery dominance.More studies are needed to explain this phenomenon.展开更多
This essay starts with a brief introduction to dominant status of English language in the world and then tries to explore the language ideology and language policies behind this phenomenon. And finally, some justifica...This essay starts with a brief introduction to dominant status of English language in the world and then tries to explore the language ideology and language policies behind this phenomenon. And finally, some justification and particular consideration on the effects of English dominance in China will be discussed.展开更多
When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly r...When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly reduced, and most of the time, the radio waves will reach the user by bypass diffraction. Therefore, the traditional path loss model is no longer applicable, and the improved model should be proposed. In this paper, we firstly proposed an indoor radio propagation model based on dominant path in which the received signal strength has nothing to do with the direct distance between user and access point, but is related to the length of dominant path. Then on the basis of dominant path model, the NLOS influence is considered in order to further improve the accuracy of dominant path model. Experimental results demonstrated that the proposed dominant path model can improve the accuracy of traditional path loss model remarkably.展开更多
文摘In this paper, we provide some new necessary and sufficient conditions for generalized diagonally dominant matrices and also obtain some criteria for nongeneralized dominant matrices.
文摘AIM To investigate the relationship of inferior wall ischemia on myocardial perfusion imaging in patients with nondominant right coronary artery anatomy.METHODS This was a retrospective observational analysis of consecutive patients who presented to the emergency department with primary complaint of chest pain.Only patients who underwent single photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI)were included.Patients who showed a reversible defect on SPECT MPI and had coronary angiography during the same hospitalization was analyzed.Patients with prior history of coronary artery disease(CAD)including history of percutaneous coronary intervention and coronary artery bypass graft surgerys were excluded.True positive and false positive results were identified on the basis of hemodynamically significant CAD on coronary angiography,in the same territory as identified on SPECT MPI.Coronary artery dominance was determined on coronary angiography.Patients were divided into group 1 and group 2.Group1 included patients with non-dominant right coronary artery(RCA)(left dominant and codominant).Group2 included patients with dominant RCA anatomy.Demographics,baseline characteristics and positive predictive value(PPV)were analyzed for the two groups.RESULTS The mean age of the study cohort was 57.6 years.Sixtyone point seven percent of the patients were males.The prevalence of self-reported diabetes mellitus,hypertension and dyslipidemia was 36%,71.9%and 53.9%respectively.A comparison of baseline characteristics between the two groups showed that patients with a non-dominant RCA were more likely to be men.For inferior wall ischemia on SPECT MPI,patients in study group 2 had a significantly higher PPV,32/42(76.1%),compared to patients in group 1,in which only 3 out of the 29 patients(10.3%)had true positive results(P value<0.001 Z test).The difference remained statistically significant even when only patients with left dominant coronary system(without co-dominant)were compared to patients with right dominant system(32/40,76.1%in right dominant group,3/19,15.8%in left dominant group,P value<0.001 Z test).There was no significant difference in mean hospital stay,re-hospitalization,and in-hospital mortality between the two groups.CONCLUSION The positive predictive value of SPECT MPI for inferior wall ischemia is affected by coronary artery dominance.More studies are needed to explain this phenomenon.
文摘This essay starts with a brief introduction to dominant status of English language in the world and then tries to explore the language ideology and language policies behind this phenomenon. And finally, some justification and particular consideration on the effects of English dominance in China will be discussed.
文摘When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly reduced, and most of the time, the radio waves will reach the user by bypass diffraction. Therefore, the traditional path loss model is no longer applicable, and the improved model should be proposed. In this paper, we firstly proposed an indoor radio propagation model based on dominant path in which the received signal strength has nothing to do with the direct distance between user and access point, but is related to the length of dominant path. Then on the basis of dominant path model, the NLOS influence is considered in order to further improve the accuracy of dominant path model. Experimental results demonstrated that the proposed dominant path model can improve the accuracy of traditional path loss model remarkably.
