824 research outputs found
Existence Result for Impulsive Differential Equations with Integral Boundary Conditions
We investigate the following differential equations: -(y[1](x))'+q(x)y(x)=λf(x,y(x)), with impulsive and integral boundary conditions -Δ(y[1](xi))=Ii(y(xi)), i=1,2,…,m, y(0)-ay[1](0)=∫0ωg0(s)y(s)ds, y(ω)-by[1](ω)=∫0ωg1(s)y(s)ds, where y[1](x)=p(x)y'(x). The expression of Green's function and the existence of positive solution for the system are obtained. Upper and lower bounds for positive solutions are also given. When p(t), I(·), g0(s), and g1(s) take different values, the system can be simplified to some forms which has been studied in the works by Guo and LakshmiKantham (1988), Guo et al. (1995), Boucherif (2009), He et al. (2011), and Atici and Guseinov (2001). Our discussion is based on the fixed point index theory in cones
Prototyping a Social Media Flooding Photo Screening System Based on Deep Learning and Crowdsourcing
This thesis aims to implement a prototype system to screen flooding photos from social media. These photos, associated with their geographic locations, can provide free, timely, and reliable visual information about flood events to the decision makers. This system is designed for the application to the real social media images, including several key functions: tweets downloading, image downloading, flooding photo detection, and human verification via a WebGIS application. In this study, a training dataset of 5,000 flooding photos was built based on an iterative method; a convolutional neural network (CNN) was then trained and applied to detect flooding photos. Also, the CNN can be re- trained by a larger training dataset after adding the verified flooding photos to the training set. The flooding photo detection result shows that the trained CNN achieved a total accuracy of 93% in a balanced test set (the flooding and non-flooding class have the same number of samples) and precisions of 46% -- 63% in the imbalanced real-time tweets (the number of flooding samples are over 20 times larger than non-flooding), demonstrating the feasibility of the proposed pipeline. The system is flexible to change the classifier, so that detecting other disasters (e.g., tornado) is possible
Establishment of core collection from apricot germplasm in China
This study aimed at establishing a core collection based on the analysis of data from simple sequence repeat (SSR) alleles and morphological and agronomical traits (MOR) of the primary core collection from apricot germplasm resources. The index of genetic diversity, and frequency ratios of retention and loss of the alleles were studied between cluster and random sampling methods at five sampling ratios. The results demonstrate that the cluster sampling method preceded random sampling, and cluster sampling of SSR combined with MOR at the rate of 80% was the best sampling strategy among all the sampling methods. Based on this sampling strategy, 120 accessions were selected as the core collection of apricot, which retained 100% alleles in the primary core collection and 100% phenotypic characters. The core collection developed had also been evaluated by using the data of six quantitative traits, which showed that the established core collection could well represent the genetic diversity of the original collection of 1501 apricot accessions.Keywords: Apricot, core collection, sampling strategy, simple sequence repeat (SSR) molecular markerAfrican Journal of Biotechnology Vol. 12(37), pp. 5577-558
Regulation of CCL5 Expression in Smooth Muscle Cells Following Arterial Injury
Chemokines play a crucial role in inflammation and in the pathophysiology of atherosclerosis by recruiting inflammatory immune cells to the endothelium. Chemokine CCL5 has been shown to be involved in atherosclerosis progression. However, little is known about how CCL5 is regulated in vascular smooth muscle cells. In this study we report that CCL5 mRNA expression was induced and peaked in aorta at day 7 and then declined after balloon artery injury, whereas IP-10 and MCP-1 mRNA expression were induced and peaked at day 3 and then rapidly declined
Flotation Characteristics and Particle Size Distribution of Micro-fine Low Rank Coal
AbstractIn this work, attempts to float the micro-fine low rank coal and its particle size distribution in the flotation were made. Then, standard screening, FT-IR, XRD and SEM were adopted to characterize the size distribution and flotation of micro-fine Shendong low rank coal. The results indicated that the size fraction of -0.045mm was the dominant size fraction in raw coal with a yield of 91.65% and ash content of 46.25%. Flotation of Shendong low rank coal required a larger dosage of collector, 50kg/t of diesel oil, to achieve a higher combustible matter recovery (63.25%) and flotation efficiency index (40.70%) accompanied with a significant decrease in ash content (22.44 percentage points) due to the hydrophilicity of coal surface. Under this condition, concentrate contained 83.38% of -0.045mm size fraction (38.04% of total particles in feed) with ash content of 24.98%. In comparison, tailing was almost consisted of -0.045mm fraction (93.63%) with a higher ash content of 60.82%. It seems that the higher ash particles in feed were largely migrated in tailing at a proper collector dosage. The analysis of FT-IR, XRD and SEM would contribute to the understanding of the flotation and size distribution
Discovery of An Active Intermediate-Mass Black Hole Candidate in the Barred Bulgeless Galaxy NGC 3319
We report the discovery of an active intermediate-mass black hole (IMBH)
candidate in the center of nearby barred bulgeless galaxy . The
point X-ray source revealed by archival Chandra and XMM-Newton observations is
spatially coincident with the optical and UV galactic nuclei from Hubble Space
Telescope observations. The spectral energy distribution derived from the
unresolved X-ray and UV-optical flux is comparable with active galactic nuclei
(AGNs) rather than ultra-luminous X-ray sources, although its bolometric
luminosity is only . Assuming an Eddington
ratio range between 0.001 and 1, the black hole mass (M_\rm{BH}) will be
located at , placing it in the so-called
IMBH regime and could be the one of the lowest reported so far. Estimates from
other approaches (e.g., fundamental plane, X-ray variability) also suggest
M_\rm{BH}\lesssim10^5~M_{\odot}.Similar to other BHs in bulgeless galaxies,
the discovered IMBH resides in a nuclear star cluster with mass of
. The detection of such a low-mass BH offers us an
ideal chance to study the formation and early growth of SMBH seeds, which may
result from the bar-driven inflow in late-type galaxies with a prominent bar
such as .Comment: ApJ accepted, 2 tables, 6 figure
Antagonistic actions of boron against inhibitory effects of aluminum toxicity on growth, CO2 assimilation, ribulose-1,5-bisphosphate carboxylase/oxygenase, and photosynthetic electron transport probed by the JIP-test, of Citrus grandis seedlings
<p>Abstract</p> <p>Background</p> <p>Little information is available on the amelioration of boron (B) on aluminum (Al)-induced photosynthesis inhibition. Sour pummelo (<it>Citrus grandis</it>) seedlings were irrigated for 18 weeks with nutrient solution containing 4 B levels (2.5, 10, 25 and 50 μM H<sub>3</sub>BO<sub>3</sub>) × 2 Al levels (0 and 1.2 mM AlCl<sub>3</sub>·6H<sub>2</sub>O). The objectives of this study were to determine how B alleviates Al-induced growth inhibition and to test the hypothesis that Al-induced photosynthesis inhibition can be alleviated by B <it>via </it>preventing Al from getting into shoots.</p> <p>Results</p> <p>B had little effect on plant growth, root, stem and leaf Al, leaf chlorophyll (Chl), CO<sub>2 </sub>assimilation, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Chl a fluorescence (OJIP) transient and related parameters without Al stress except that root, stem and leaf B increased with increasing B supply and that 50 μM B decreased slightly root dry weight. Al-treated roots, stems and leaves displayed a higher or similar B. B did not affect root Al under Al stress, but decreased stem and leaf Al level. Shoot growth is more sensitive to Al stress than root growth, CO<sub>2 </sub>assimilation, Chl, Rubisco, OJIP transient and most related parameters. Al-treated leaves showed decreased CO<sub>2 </sub>assimilation, but increased or similar intercellular CO<sub>2 </sub>concentration. Both initial and total Rubisco activity in Al-treated leaves decreased to a lesser extent than CO<sub>2 </sub>assimilation. Al decreased maximum quantum yield of primary photochemistry and total performance index, but increased minimum fluorescence, K-band, relative variable fluorescence at J- and I-steps. B could alleviate Al-induced increase or decrease for all these parameters. Generally speaking, the order of B effectiveness was 25 μM > 10 μM ≥ 50 μM (excess B) > 2.5 μM.</p> <p>Conclusion</p> <p>We propose that Al-induced photosynthesis inhibition was mainly caused by impaired photosynthetic electron transport chain, which may be associated with growth inhibition. B-induced amelioration of root inhibition was probably caused by B-induced changes in Al speciation and/or sub-cellular compartmentation. However, B-induced amelioration of shoot and photosynthesis inhibition and photoinhibitory damage occurring at both donor and acceptor sides of photosystem II could be due to less Al accumulation in shoots.</p
PI3K-GLUT4 Signal Pathway Associated with Effects of EX-B3 Electroacupuncture on Hyperglycemia and Insulin Resistance of T2DM Rats
Objectives. To explore electroacupuncture’s (EA’s) effects on fasting blood glucose (FBG) and insulin resistance of type 2 diabetic mellitus (T2DM) model rats and give a possible explanation for the effects. Method. It takes high fat diet and intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) for model preparation. Model rats were randomly divided into T2DM Model group, EA weiwanxiashu (EX-B3) group, and sham EA group (n=12/group). EA (2 Hz continuous wave, 2 mA, 20 min/day, 6 days/week, 4 weeks) was applied as intervention. FBG, area under curve (AUC) of oral glucose tolerance test (OGTT), insulin resistance index (HOMA-IR), pancreatic B cell function index (HOMA-B), skeletal muscle phosphorylated phosphatidylinositol-3-kinase (PI3K), glucose transporter 4 (GLUT4), and membrane GLUT4 protein expression were measured. Results. EA weiwanxiashu (EX-B3) can greatly upregulate model rat’s significantly reduced skeletal muscle PI3K (Y607) and membrane GLUT4 protein expression (P<0.01), effectively reducing model rats’ FBG and AUC of OGTT (P<0.01). The effects are far superior to sham EA group. Conclusion. EA weiwanxiashu (EX-B3) can upregulate skeletal muscle phosphorylated PI3K protein expression, to stimulate membrane translocation of GLUT4 and thereby increase skeletal muscle glucose intake to treat T2DM
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