1,390 research outputs found

    Chaotic motion in multi-black hole spacetimes and holographic screens

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    We investigate the geodesic motion in DD-dimensional Majumdar-Papapetrou multi-black hole spacetimes and find that the qualitative features of the D=4 case are shared by the higher dimensional configurations. The motion of timelike and null particles is chaotic, the phase space being divided into basins of attraction which are separated by a fractal boundary, with a fractal dimension dBd_B. The mapping of the geodesic trajectories on a screen placed in the asymptotic region is also investigated. We find that the fractal properties of the phase space induces a fractal structure on the holographic screen, with a fractal dimension dB1d_B-1.Comment: 8 pages, 5 figure

    Utilization of watermelon rinds and sharlyn melon peels as a natural source of dietary fiber and antioxidants in cake

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    AbstractThe aim of this work was to evaluate some physical and chemical properties of watermelon rind and sharlyn melon peel powders and its utilization as partially, substituted of wheat flour at levels of 2.5%, 5.0% and 7.5% or fat at levels of 5.0%, 10% and 15% in cake making. Watermelon rinds had higher moisture, ash, fat, protein and carbohydrates 10.61%, 13.09%, 2.44%, 11.17% and 56.00%, respectively as compared to sharlyn melon peels. On the other hand, sharlyn melon peels had higher content crud fiber (29.59%) than in watermelon rinds (17.28%). The water absorption capacity (WAC) and oil absorption capacity (OAC) of sharlyn melon peels was higher than that of watermelon rinds being 7.7, 7.13 (g water/g) and 2.24, 1.65 (g oil/g), respectively. Watermelon rinds showed significantly greater free radical scavenging activity and β-carotene (39.7% and 96.44%), respectively compared to sharlyn melon peels. It contained different types of phenolic compounds, the most abundant one was 4-hydroxybenzoic acid (958.3μg/g dw) followed by vanillin (851.8μg/g dw), while the lowest phenolic compound was coumaric acid (8.8μg/g dw). On the other hand four phenolic compounds were identified in sharlyn melon peels namely, 4-hydroxybenzoic acid, vanillin, chlorgenic acid, and coumaric acid. The incorporation of WMR and SMP powders in cakes batter at all the studied levels enhanced the volume and specific volume of the baked cakes to overcome, those of the control. These materials also retard staling of cakes and inhibition the lipids oxidation and free fatty acids formation during storage. It is revealed that, substitution of 5% flour and 10% fat with watermelon rinds and sharlyn melon peels produced acceptable cakes which were not significantly different with the control

    Additive Pattern Database Heuristics

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    We explore a method for computing admissible heuristic evaluation functions for search problems. It utilizes pattern databases, which are precomputed tables of the exact cost of solving various subproblems of an existing problem. Unlike standard pattern database heuristics, however, we partition our problems into disjoint subproblems, so that the costs of solving the different subproblems can be added together without overestimating the cost of solving the original problem. Previously, we showed how to statically partition the sliding-tile puzzles into disjoint groups of tiles to compute an admissible heuristic, using the same partition for each state and problem instance. Here we extend the method and show that it applies to other domains as well. We also present another method for additive heuristics which we call dynamically partitioned pattern databases. Here we partition the problem into disjoint subproblems for each state of the search dynamically. We discuss the pros and cons of each of these methods and apply both methods to three different problem domains: the sliding-tile puzzles, the 4-peg Towers of Hanoi problem, and finding an optimal vertex cover of a graph. We find that in some problem domains, static partitioning is most effective, while in others dynamic partitioning is a better choice. In each of these problem domains, either statically partitioned or dynamically partitioned pattern database heuristics are the best known heuristics for the problem

    THE PROTECTIVE ROLE OF OMEGA-3 AGAINST GENOTOXICITY AND REPRODUCTIVE TOXICITY OF COBALT OXIDE NANOPARTICLES ACUTE TREATMENT IN MALE MICE

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    Objective: Cobalt nanoparticles (NPs), especially cobalt oxide NPs (Co3O4 NPs) are attracting unique shaped NPs that are used in different biomedical applications and medicine. Different in vitro studies report their toxic and carcinogenic effect but limited in vivo studies were present on its genotoxic potential. The present study was aimed to evaluate the genotoxic potential of Co3O4 NPs on bone marrow cells and sperms and the protective role of omega-3 in male albino mice.Methods: Animals were segregated into four groups that were orally treated for 3 consecutive days, Group 1: Negative control; Group 2: Omega-3 (250 mg/kg); Group 3: Co3O4 NPs (20 mg/kg); and Group 4: Combined group (250 mg/kg Omega-3 and Co3O4 NPs 20 mg/kg).Results: The present results show that Co3O4 NPs administration significantly increased number of micronucleated polychromatic erythrocytes (PCEs)/1000 PCEs, sperm abnormalities, and DNA damage, significantly decreased sperm motility and concentration in comparison to negative control group. However, Omega-3 administration in the combined group modulates the genotoxic potential of Co3O4 NPs in comparison to Co3O4 NPs group.Conclusion: The present study reports the genotoxic potential of Co3O4 NPs in vivo and assesses the protective role of Omega-3 administration due to its antioxidant effect

    Real-time polymerase chain reaction methods for strain specific identification and enumeration of strain Lacticaseibacillus paracasei 8700:2

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    IntroductionReliable and accurate methods for probiotic identification and enumeration, at the strain level plays a major role in confirming product efficacy since probiotic health benefits are strain-specific and dose-dependent. In this study, real-time PCR methods were developed for strain specific identification and enumeration of L. paracasei 8700:2, a probiotic strain that plays a role in fighting the common cold.MethodsThe assay was designed to target a unique region in L. paracasei 8700:2 genome sequence to achieve strain level specificity. The identification assay was evaluated for specificity and sensitivity. The enumeration viability real-time PCR (v-qPCR) method was first optimized for the viability treatment, then the method was evaluated for efficiency, limit of quantification, precision, and its performance was compared to plate count (PC) and viability droplet digital PCR (v-ddPCR) methods.ResultsThe identification method proved to be strain specific and highly sensitive with a limit of detection of 0.5 pg of DNA. The optimal viability dye (PMAxx) concentration was 50 μM. The method was efficient (> 90% with R2 values > 0.99), with a linear dynamic range between 6*102 and 6*105 copies. The method was highly precise with a relative standard deviation below 5%. The Pearson correlation coefficient (r) was 0.707 for PC and v-qPCR methods, and 0.922 for v-qPCR and v-ddPCR. Bland-Altman method comparison showed that v-qPCR always gave higher values compared to PC method (relative difference ranging from 119% to 184%) and showed no consistent trend (relative difference ranging from −20% to 22%) when comparing v-qPCR and v-ddPCR methods.DiscussionThe difference between PC and v-PCR methods can potentially be attributed to the proportion of cells that exist in a viable but non culturable (VBNC) state, which can be count by v-PCR but not with PC. The developed v-qPCR method was confirmed to be strain specific, sensitive, efficient, with low variance, able to count VBNC cells, and has shorter time to results compared to plate count methods. Thus, the identification and enumeration methods developed for L. paracasei 8700:2 will be of great importance to achieve high quality and efficacious probiotic products

    Intelligent swarm algorithms for optimizing nonlinear sliding mode controller for robot manipulator

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    This work introduces an accurate and fast approach for optimizing the parameters of robot manipulator controller. The approach of sliding mode control (SMC) was proposed as it documented an effective tool for designing robust controllers for complex high-order linear and nonlinear dynamic systems operating under uncertain conditions. In this work Intelligent particle swarm optimization (PSO) and social spider optimization (SSO) were used for obtaining the best values for the parameters of sliding mode control (SMC) to achieve consistency, stability and robustness. Additional design of integral sliding mode control (ISMC) was implemented to the dynamic system to achieve the high control theory of sliding mode controller. For designing particle swarm optimizer (PSO) and social spider optimization (SSO) processes, mean square error performances index was considered. The effectiveness of the proposed system was tested with six degrees of freedom robot manipulator by using (PUMA) robot. The iteration of SSO and PSO algorithms with mean square error and objective function were obtained, with best fitness for (SSO) =4.4876 -6 and (PSO)=3.4948 -4

    Electrical expression of spin accumulation in ferromagnet/semiconductor structures

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    We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.Comment: A review to appear in Mod. Phys. Lett.

    The power of DNA based methods in probiotic authentication

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    IntroductionThe global probiotic market is growing rapidly, and strict quality control measures are required to ensure probiotic product efficacy and safety. Quality assurance of probiotic products involve confirming the presence of specific probiotic strains, determining the viable cell counts, and confirming the absence of contaminant strains. Third-party evaluation of probiotic quality and label accuracy is recommended for probiotic manufacturers. Following this recommendation, multiple batches of a top selling multi-strain probiotic product were evaluated for label accuracy.MethodsA total of 55 samples (five multi-strain finished products and 50 single-strain raw ingredients) containing a total of 100 probiotic strains were evaluated using a combination of molecular methods including targeted PCR, non-targeted amplicon-based High Throughput Sequencing (HTS), and non-targeted Shotgun Metagenomic Sequencing (SMS).ResultsTargeted testing using species-specific or strain-specific PCR methods confirmed the identity of all strains/species. While 40 strains were identified to strain level, 60 strains were identified to species level only due to lack of strain-specific identification methods. In amplicon based HTS, two variable regions of 16S rRNA gene were targeted. Based on V5–V8 region data, ~99% of total reads per sample corresponded to target species, and no undeclared species were detected. Based on V3–V4 region data, ~95%–97% of total reads per sample corresponded to target species, while ~2%–3% of reads matched undeclared species (Proteus species), however, attempts to culture Proteus confirmed that all batches were free from viable Proteus species. Reads from SMS assembled to the genomes of all 10 target strains in all five batches of the finished product.DiscussionWhile targeted methods enable quick and accurate identification of target taxa in probiotic products, non-targeted methods enable the identification of all species in a product including undeclared species, with the caveats of complexity, high cost, and long time to result

    Beberapa Faktor yang Berhubungan dengan Diakuinya Seseorang sebagai Pemimpin Opini dan Manfaatnya untuk Kegiatan Penyuluhan

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    Opinion Leader at a certain areas, highly contributes to diffusion and adoption process, and has certain effect to social system whether the farmers rejected or accepted to a innovation. The research identified existence and function of Opinion Leader in an areas and analyzed correlated factors of recognition of Opinion Leader. Respondent were farmers of Floating Net Fish Culture at Coklat Area, Cirata Dam, District of Cianjur, West Java Province. The survey conducted since February until May 2005.The result showed that the farmers population, there were eight persons who considered by the respondents as sources of innovation and opinion. Futhermore internal characteristic had a positive value correlation among factors toward recognition level of Opinion Leader, but external characteristic showed negative correlation. Specially, the function of Opinion Leader those were strong correlation toward recognition farmers level to Opinion Leader
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