5,696 research outputs found

    Special studies of AROD system concepts and designs

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    Signal to noise ratios in airborne range and orbit determination system, and carrier and range loop performance analyse

    Cross section normalization in proton-proton collisions at s\sqrt{s} = 2.76 TeV and 7 TeV, with ALICE at LHC

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    Measurements of the cross sections of the reference processes seen by the ALICE trigger system were obtained based on beam properties measured from van der Meer scans. The measurements are essential for absolute cross section determinations of physics processes. The paper focuses on instrumental and technical aspects of detectors and accelerators, including a description of the extraction of beam properties from the van der Meer scan. As a result, cross sections of reference processes seen by the ALICE trigger system are given for proton-proton collisions at two energies; s\sqrt{s}=2.76 TeV and 7 TeV, together with systematic uncertainties originating from beam intensity measurements and other detector effects. Consistency checks were performed by comparing to data from other experiments in LHC.Comment: Quark Matter 2011 Conference Proceedings, 4 pages, 2 figure

    Титульні сторінки

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    Influenza virus and vesicular stomatitis virus (VSV) obtain their lipid envelope by budding through the plasma membrane of infected cells. When monolayers of Madin-Darby canine kidney (MDCK) cells, a polarized epithelial cell line, are infected with fowl plague virus (FPV), an avian influenza virus, or with VSV, new FPV buds through the apical plasma membrane whereas VSV progeny is formed by budding through the basolateral plasma membrane. FPV and VSV were isolated from MDCK host cells prelabeled with [32P]orthophosphate and their phospholipid compositions were compared. Infection was carried out at 31 degrees C to delay cytopathic effects of the virus infection, which lead to depolarization of the cell surface. 32P-labeled FPV was isolated from the culture medium, whereas 32P-labeled VSV was released from below the cell monolayer by scraping the cells from the culture dish 8 h after infection. At this time little VSV was found in the culture medium, indicating that the cells were still polarized. The phospholipid composition of the two viruses was distinctly different. FPV was enriched in phosphatidylethanolamine and phosphatidylserine and VSV in phosphatidylcholine, sphingomyelin, and phosphatidylinositol. When MDCK cells were trypsinized after infection and replated, non-infected control cells attached to reform a confluent monolayer within 4 h, whereas infected cells remained in suspension. FPV and VSV could be isolated from the cells in suspension and under these conditions the phospholipid composition of the two viruses was very similar. We conclude that the two viruses obtain their lipids from the plasma membrane in the same way and that the different phospholipid compositions of the viruses from polarized cells reflect differences in the phospholipid composition of the two plasma membrane domains

    FUZZY LOGIC BASED ZSI USING PMSG FOR WECS

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    In recent decades various renewable energy resources have attracted a lot of attention because they are pollution-free and inexhaustible. Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships

    Hysteretic clustering in granular gas

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    Granular material is vibro-fluidized in N=2 and N=3 connected compartments, respectively. For sufficiently strong shaking the granular gas is equi-partitioned, but if the shaking intensity is lowered, the gas clusters in one compartment. The phase transition towards the clustered state is of 2nd order for N=2 and of 1st order for N=3. In particular, the latter is hysteretic. The experimental findings are accounted for within a dynamical model that exactly has the above properties

    Molecular Structure and Diversity of PBAN/pyrokinin Family Peptides in Ants

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    Neuropeptides are the largest group of insect hormones. They are produced in the central and peripheral nervous systems and affect insect development, reproduction, feeding, and behavior. A variety of neuropeptide families have been identified in insects. One of these families is the PBAN/pyrokinin family defined by a common FXPRLamide or similar amino acid fragment at the C-terminal end. These peptides, found in all insects studied thus far, have been conserved throughout evolution. The most well studied physiological function is regulation of moth sex pheromone biosynthesis through the pheromone biosynthesis activating neuropeptide (PBAN), although several developmental functions have also been reported. Over the past years we have extended knowledge of the PBAN/pyrokinin family of peptides to ants, focusing mainly on the fire ant, Solenopsis invicta. The fire ant is one of the most studied social insects and over the last 60 years a great deal has been learned about many aspects of this ant, including the behaviors and chemistry of pheromone communication. However, virtually nothing is known about the regulation of these pheromone systems. Recently, we demonstrated the presence of PBAN/pyrokinin immunoreactive neurons in the fire ant, and identified and characterized PBAN and additional neuropeptides. We have mapped the fire ant PBAN gene structure and determined the tissue expression level in the central nervous system of the ant. We review here our research to date on the molecular structure and diversity of ant PBAN/pyrokinin peptides in preparation for determining the function of the neuropeptides in ants and other social insects

    Condensation phase transitions of symmetric conserved-mass aggregation model on complex networks

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    We investigate condensation phase transitions of symmetric conserved-mass aggregation (SCA) model on random networks (RNs) and scale-free networks (SFNs) with degree distribution P(k)kγP(k) \sim k^{-\gamma}. In SCA model, masses diffuse with unite rate, and unit mass chips off from mass with rate ω\omega. The dynamics conserves total mass density ρ\rho. In the steady state, on RNs and SFNs with γ>3\gamma>3 for ω\omega \neq \infty, we numerically show that SCA model undergoes the same type condensation transitions as those on regular lattices. However the critical line ρc(ω)\rho_c (\omega) depends on network structures. On SFNs with γ3\gamma \leq 3, the fluid phase of exponential mass distribution completely disappears and no phase transitions occurs. Instead, the condensation with exponentially decaying background mass distribution always takes place for any non-zero density. For the existence of the condensed phase for γ3\gamma \leq 3 at the zero density limit, we investigate one lamb-lion problem on RNs and SFNs. We numerically show that a lamb survives indefinitely with finite survival probability on RNs and SFNs with γ>3\gamma >3, and dies out exponentially on SFNs with γ3\gamma \leq 3. The finite life time of a lamb on SFNs with γ3\gamma \leq 3 ensures the existence of the condensation at the zero density limit on SFNs with γ3\gamma \leq 3 at which direct numerical simulations are practically impossible. At ω=\omega = \infty, we numerically confirm that complete condensation takes place for any ρ>0\rho > 0 on RNs. Together with the recent study on SFNs, the complete condensation always occurs on both RNs and SFNs in zero range process with constant hopping rate.Comment: 6 pages, 6 figure

    Sudden Collapse of a Granular Cluster

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    Single clusters in a vibro-fluidized granular gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the cluster diffuses out into the uniform distribution in a self-similar way, with an anomalous diffusion exponent 1/3.Comment: 4 pages, 4 figures. Figure quality has been reduced in order to decrease file-siz

    On the effectiveness of supplemental instruction: a systematic review of supplemental instruction and peer-assisted study sessions literature between 2001 and 2010

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    Supplemental instruction (SI)—variously known as peer-assisted learning, peer-assisted study sessions, and other names—is a type of academic support intervention popular in higher education. In SI sessions, a senior student facilitates peer learning between undergraduates studying a high-risk course. This article presents a systematic review of the literature between 2001 and 2010 regarding the effectiveness of SI. Twenty-nine studies met the inclusion criteria. Due to methodological heterogeneity and lack of consistency defining the SI treatment, qualitative synthesis methods were applied. For seven included studies, however, an effect size of SI participation on final grades was calculated, ranging from d = 0.29 to d = 0.60. The findings of the review are consistent with claims validated by the U.S. Department of Education in the 1990s that participation in SI is correlated with higher mean grades, lower failure and withdrawal rates, and higher retention and graduation rates
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