On a Problem of Harary and Schwenk on Graphs with Distinct Eigenvalues

Harary and Schwenk posed the problem forty years ago: Which graphs have distinct adjacency eigenvalues? In this paper, we obtain a necessary and sufficient condition for an Hermitian matrix with simple spectral radius and distinct eigenvalues. As its application, we give an algebraic characterization to the Harary-Schwenk's problem. As an extension of their problem, we also obtain a necessary and sufficient condition for a positive semidefinite matrix with simple least eigenvalue and distinct eigenvalues, which can provide an algebraic characterization to their problem with respect to the (normalized) Laplacian matrix.Comment: 11 page

Effects of Financial Inclusion on Poverty in WAEMU: Empirical Evidence Through the Channels of Income Inequality and Growth

In WAEMU, financial inclusion has been made a priority with the adoption in 2016 of the Regional Financial Inclusion Strategy. It constitutes a privileged instrument promoting the integration of the most disadvantaged social strata into the economic and social fabric of the Union. This paper examines the contribution of financial inclusion to poverty reduction. The study focuses on the eight WAEMU countries and covers the period 2008-2020. The results obtained by the method of triple least squares show that on the one hand financial inclusion reduces income inequality and subsequently reduces poverty and that on the other hand it does not affect economic growth. Robustness tests indicate that the overall rate of use of financial services reduces poverty both by increasing overall income and by reducing income inequality. These tests also show that for countries not plagued by terrorism, financial inclusion reduces poverty through reduced inequality and increased overall income. On the basis of these results, the paper formulates recommendations that could serve as a guideline for poverty reduction policies in WAEMU. Keywords: Financial inclusion, aggregate income, poverty DOI: 10.7176/JESD/14-13-01 Publication date:August 31st 202

PM2.5 Concentrations Indoors and Outdoors in Heavy Air Pollution Days in Winter

AbstractThe epidemiological studies have indicated that PM2.5 can increase morbidity and mortality, damage the respiratory system and the cardiovascular system, and affect the immune function. The objectives of this study are to understand PM2.5 pollution status in the households when the heavy air pollution occurs in the winter and the correlation of indoor PM2.5 pollution with outdoor, and to find out the effect of indoor human activities on the changes of indoor PM2.5 concentrations. Indoor PM2.5 concentrations were measured using CLH-2000 portable PM2.5 detector in the four households in December 7-8, 2013. When sampling indoors, the pattern of activity questionnaire was completed. The results showed that the average of indoor PM2.5 concentration is in the range of 112-416μg/m3, and the pollution level is more serious at 4 homes in Beijing in winter. Outdoor pollution, human activities and behaviors are the sources of indoor PM2.5 at homes. Human activities (cooking, smoking and cleaning) have more contribution to indoor PM2.5 than outdoor pollution. In general, the effect of indoor human activities on PM2.5 concentration is stronger than outdoor pollution and air cleaner

Peperomin E Induces Promoter Hypomethylation of Metastatic-Suppressor Genes and Attenuates Metastasis in Poorly Differentiated Gastric Cancer

Background/Aims: Peperomin E (PepE), a natural secolignan isolated from the whole plant of Peperomia dindygulensis, has been reported by ourselves and others to display potent anti-cancer effects in many types cancer cells, especially gastric cancer. However, the effects of PepE on the metastasis of poorly-differentiated gastric cancer cells and the underlying molecular mechanisms have not been well elucidated. Methods: We evaluated PepE effects on gastric cancer cell invasion and migration in vitro via wound healing and transwell assays and those on growth and metastasis in vivo using an orthotopic xenograft NOD-SCID mouse model. DNA methyltransferase (DNMT) activity was determined using a colorimetric DNMT activity/inhibition assay kit. PepE binding kinetics to DNMTs were determined using the bio-layer interferometry binding assay. Gene and protein levels of DNMTs, AMPKα-Sp1 signaling molecules, and metastatic-suppressor genes in PepE-treated gastric cancer cells were determined using quantitative reverse transcription-PCR arrays and western blotting. The effect of PepE on Sp1 binding to the DNMT promoter was determined by electrophoretic mobility-shift assay. Global DNA methylation levels were determined using liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The methylation status of silenced metastatic-suppressor genes (MSGs) in gastric cancer cells was investigated by methylation-specific PCR. Results: PepE can dose-dependently suppress invasion and migration of poorly-differentiated gastric cancer cells in vitro and in vivo with low toxicity against normal cells. Mechanistically, PepE not only covalently binds to the catalytic domain of DNMT1 and inhibits its activity (IC50 value 3.61 μM) but also down-regulates DNMT1, 3a, and 3b mRNA and protein expression in in gastric cancer cells, by disruption of the physical interaction of Sp1 with the DNMT1, 3a, and 3b promoter and mediation of the AMPKα-Sp1 signaling pathway. The dual inhibition activity of PepE toward DNMTs renders a relative global DNA hypomethylation, which induces MSG promoter hypomethylation (e.g., E-cadherin and TIMP3) and enhances their expression in gastric cancer cells. Conclusion: Collectively, our data indicated that PepE may represent a promising therapeutic lead compound for intervention in gastric cancer metastasis and may also exhibit potential as a DNA methylation inhibitor for use in epigenetic cancer therapy

Field emission property of ZnO nanowires prepared by ultrasonic spray pyrolysis

The field emission property of cold cathode emitters utilizing the ZnO nanowires with various conditions prepared by ultrasonic spray pyrolysis technique was discussed. It is found that the emission current was enhanced in the emitters having higher aspect ratio as well as smaller sheet resistance. Applying of post-annealing process, utilization of additional Mo back electrode in the cathode, and coating of Moon the ZnO nanowires resulted in the improvement of the emission current and lowering the threshold voltage. A threshold voltage of about 5.5 V/mu m to obtain 1.0 mu A/cm(2) was achieved in the sample prepared at the growth temperatures varying continuously from 250 degrees C to 300 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.ArticleSUPERLATTICES AND MICROSTRUCTURES. 84:144-153 (2015)journal articl

Study of e+e−→ppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

Using 2917 $\rm{pb}^{-1}$ of data accumulated at 3.773~$\rm{GeV}$, 44.5~$\rm{pb}^{-1}$ of data accumulated at 3.65~$\rm{GeV}$ and data accumulated during a $\psi(3770)$ line-shape scan with the BESIII detector, the reaction $e^+e^-\rightarrow p\bar{p}$ is studied considering a possible interference between resonant and continuum amplitudes. The cross section of $e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}$, $\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p})$, is found to have two solutions, determined to be ($0.059\pm0.032\pm0.012$) pb with the phase angle $\phi = (255.8\pm37.9\pm4.8)^\circ$ ($<$0.11 pb at the 90% confidence level), or $\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12$) pb with $\phi = (266.9\pm6.1\pm0.9)^\circ$ both of which agree with a destructive interference. Using the obtained cross section of $\psi(3770)\rightarrow p\bar{p}$, the cross section of $p\bar{p}\rightarrow \psi(3770)$, which is useful information for the future PANDA experiment, is estimated to be either ($9.8\pm5.7$) nb ($<17.2$ nb at 90% C.L.) or $(425.6\pm42.9)$ nb