3,432 research outputs found
Underdetermined blind source separation based on Fuzzy C-Means and Semi-Nonnegative Matrix Factorization
Conventional blind source separation is based on over-determined with more sensors than sources but the underdetermined is a challenging case and more convenient to actual situation. Non-negative Matrix Factorization (NMF) has been widely applied to Blind Source Separation (BSS) problems. However, the separation results are sensitive to the initialization of parameters of NMF. Avoiding the subjectivity of choosing parameters, we used the Fuzzy C-Means (FCM) clustering technique to estimate the mixing matrix and to reduce the requirement for sparsity. Also, decreasing the constraints is regarded in this paper by using Semi-NMF. In this paper we propose a new two-step algorithm in order to solve the underdetermined blind source separation. We show how to combine the FCM clustering technique with the gradient-based NMF with the multi-layer technique. The simulation results show that our proposed algorithm can separate the source signals with high signal-to-noise ratio and quite low cost time compared with some algorithms
Information Measures and some Distribution Approximations.
The Fisher and Kullback- Liebler information measures were calculated from the approximation of a binomial distribution by both the Poisson and the normal distributions and are applied to the approximation of a Poisson distribution by a normal distribution. In this paper the concept of relative loss in information due to approximating the distribution of a random variable by that of another distribution of is introduced, and this concept is used to determine the value of the sample size for which the relative loss in information measure is less than a given level
The Effect of Direct and Indirect Boiling on Chemical Composition and Microbial load of Disposed Waste Fish of White Nile State, Sudan
The present study was conducted to evaluate the effect of direct and indirect boiling treatments on disposed fish collected from the White Nile River, South of Eldueim town, for the benefit of being used as local fishmeal. The fish samples were identified and analyzed microbiologically and chemically. Crude protein, fat, ash, and metabolizable energy values for treated and untreated samples were found higher than those of the imported broilers concentrates by 20%, 9.7%, 51%, and 36%, respectively. The levels of calcium for direct and indirect boiling treated and untreated samples were 5.6, 4.9, and 4.82%, while for phosphorus they were 3.49, 3.06, and 3.09%, respectively. Treated and untreated samples were higher in sodium content than that of the imported concentrate by 70%. They also one and a half times higher for the phosphorus content. The total concentrations of amino acids for direct and indirect boiling treated samples were 1.21 and 1.13% for methionine and 3.51 and 3.30% for lysine, respectively. Escherichia coli. was totally eradicated by treatments. The direct and indirect boiling gave large numbers of molds and Salmonella spp., amounting to 1.00 × 106 and 2.00 × 106 and 0.50 × 106 and 0.50 × 106 cfu/g, respectively. The results indicated that disposed fish could replace imported concentrates as feedstuff after direct and indirect boiling for poultry feeding, in Sudan
Probing compact dark matter objects with microlensing in gravitationally lensed quasars
The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best COSMOGRAIL observations: HE 1104-1805, HE 0435-1223, RX J1131-1231, WFI 2033-4723, PG 1115+080, and J1206+4332, yielding a total of eight microlensing light curves, when combining independent image pairs and typically spanning ten years. We explore the microlensing signals to determine whether the standard assumptions on the stellar populations are sufficient to account for the amplitudes of the measured signals or whether additional microlenses are needed. We use the most detailed lens models to date from the H0LiCOW/TDCOSMO collaboration to derive the microlensing parameters, such as the convergence, shear, and stellar/dark matter mass fraction at the position of the quasar images. We use these parameters to generate simulated microlensing light curves. Finally, we propose a methodology based on the Kolmogorov-Smirnov test to verify whether the observed microlensing amplitudes in our data are compatible with the most standard scenario, whereby galaxies are composed of stars as compact bodies and smoothly distributed DM. Given our current sample, we show that the standard scenario cannot be rejected, in contrast with previous results by Hawkins (2020a, A&A, 633, A107), claiming that a population of stellar mass primordial black holes (PBHs) is necessary to explain the observed amplitude of the microlensing signal in lensed quasar light curves. We further estimate the number of microlensing light curves needed to effectively distinguish between the standard scenario with stellar microlensing and a scenario that describes that all the DM contained in galaxies is in the form of compact objects such as PBHs, with a mean mass of 0.2 Mo. We find that about 900 microlensing curves from the Rubin Observatory will be sufficient to discriminate between the two extreme scenarios at a 95% confidence level.</p
Effects of Some Essential Oils on Aspergillus flavus Growth and Aflatoxin Production
The present study aimed at investigating the effects of some essential oils on inhibiting fungal growth of A. flavus and aflatoxin production. Clove oil was found as the best among the six different oils tested against the radial growth at the concentration of 0.05. mL/100ml. However the other oils were also significantly better than the control except the Pumpkin oil. Different concentrations (0.00, 0.01, 0.03 and 0.05 ml/100ml) of only three of the oils were tested against the radial growth of A. flavus. Clove and Cumin oils were significantly effective than the control at all these concentrations. Although Pumpkin oil was slightly more effective than the control at its higher concentration (0.05) ml/100ml), it was not effective at its lower concentrations (0.01 and 0.03 ml/100ml). Clove oil was also the best in suppressing mycelial growth at the concentration of 0.05 ml/100ml. However, the other oils were also significantly better than the control, while, Pumpkin oil was non-effective. Spore germination was also affected by the oils tested. Clove oil gave complete inhibition at its higher concentration followed by Cumin, Rehan, Garlic and Desert date, while Pumpkin oil was the least one. Aflatoxin production was highly affected by the essential oils tested. Clove and Cumin exhibited a complete inhibition, followed by Rehan; Garlic and Desert date while Pumpkin oil was non-effective
Gauge Theories with Time Dependent Couplings and their Cosmological Duals
We consider the N=4 SYM theory in flat 3+1 dimensional spacetime with a time
dependent coupling constant which vanishes at , like . In an
analogous quantum mechanics toy model we find that the response is singular.
The energy diverges at , for a generic state. In addition, if the
phase of the wave function has a wildly oscillating behavior, which does not
allow it to be continued past . A similar effect would make the gauge
theory singular as well, though nontrivial effects of renormalization could
tame this singularity and allow a smooth continuation beyond . The gravity
dual in some cases is known to be a time dependent cosmology which exhibits a
space-like singularity at . Our results, if applicable in the gauge theory
for the case of the vanishing coupling, imply that the singularity is a genuine
sickness and does not admit a meaningful continuation. When the coupling
remains non-zero and becomes small at , the curvature in the bulk becomes
of order the string scale. The gauge theory now admits a time evolution beyond
this point. In this case, a finite amount of energy is produced which possibly
thermalizes and leads to a black hole in the bulk.Comment: 45 pages, 1 figure; v2. minor modifications; v3: PRD version,
conclusions in the field theory case significantly revised to include
possible renormalization effects, quantum mechanics toy model unchanged,
abstract and introduction revised, additional subsection 4.1 adde
Detection of FXIII gene V34L and fibrinogen β-gene -455G/A polymorphisms among Saudi Arabia population via polymerase chain reaction-reverse hybridization technique
FXIII gene Val34Leu variant appears to be associated with decreased risk of myocardial infarction and venous thromboembolism as well as with increased risk of intracerebral hemorrhage. Fibrinogen β-gene SNP -455G/A are associated with differences in the plasma levels of fibrinogen and severity of arterial disease. The aim of the present work was to study the prevalence of FXIII gene V34L and Fibrinogen β-gene -455G/A SNPs in Saudi population. Among 200 blood samples randomly collected from unrelated healthy Saudi subjects, FXIII gene V34L and Fibrinogen β-gene -455G/A SNPs were genotyped via cardiovascular disease (CVD) StripAssay (ViennaLab, Austria. Homozygous (V/V) and heterozygous (V/L) genotypes were detected with 96 and 4%, respectively, among FXIII gene V34L genotypes, whereas (L/L) genotype was not found. The allele frequency was 0.98 for V allele and 0.02 for L allele. Three genotypes of Fibrinogen β-gene -455G/A SNP (GG, GA and AA) were obtained and its prevalence (%) was 70, 25 and 5, respectively. The frequency of G allele was 0.825 and 0.175 for A allele. Prevalence of FXIII gene Vl34L polymorphism and its allele frequency are in line with other Asian populations. Distribution of β-gene -455G/A genotypes and allele frequency are in accordance with previous reports in different ethnic groups. This is the first time to report these polymorphisms in Saudi Arabia population. This study provides valuable information on Saudi genetic background in comparison with other populations. In addition, it serves as a template for future clinical research involving cardiovascular and cerebrovascular diseases.Key words: FXIII gene V34L, fibrinogen β-gene -455G/A, polymorphisms, Saudi Arabia
Predicton of interface level height of stratified liquid-liquid flow using artficial neural network
In this study, artificial neural network (ANN) was used to predict the interface level height (ILH) of two immiscible liquids flowing in a horizontal pipe. A three-layer feed-forward back-propagation (FFBP) neural network was constructed and trained with experimental data of two different liquid-liquid flow systems reported in the literature. The all studied flow patterns were stratified flow (stratified smooth and stratified wavy with or without droplets at interface ). The input parameters of the ANN model were superficial velocity of phases, pipe diameter, the ratio of the lighter phase density to the heavier phase density (ρlp/ρhp) and the ratio of the lighter phase viscosity to the heavier phase viscosity (μlp/μhp), while the interface level height (ILH) of phases was its output. The Levenberg–Marquardt (LM) algorithm, the hyperbolic tangent sigmoid and the linear activation functions were used for training and developing the ANN. Optimal configuration of the ANN model was determined using minimizing the mean absolute percent error (MAPE) and mean square errors (MSE) between experimental and predicted ILH data by the ANN model. The results showed that the optimal configuration was a network with five neurons in hidden layer that was highly accurate in predicting the interface level. MAPE and correlation coefficient (R) between the experimental and predicted values were determined as 1.8% and 0.9962 for training, and 1.52% and 0.9996 for testing date sets, respectively
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