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Sample records for range hopping mechanism

  1. Mechanisms of hop inhibition: hop ionophores.

    Science.gov (United States)

    Behr, Jürgen; Vogel, Rudi F

    2009-07-22

    In this work, the mechanism of hop inhibition toward (beer spoiling) bacteria is revised. The mode of action of iso-alpha-acids was investigated via bilayer lipid membrane (BLM) measurements and growth challenges of hop-sensitive and -resistant Lactobacillus brevis strains in the presence of uncouplers of class I and II or a H(+)/Mn(2+) exchanger. The antibacterial action of iso-alpha-acids as proton ionophores could be confirmed by the BLM measurements; however, the reported ionophore properties, as electroneutral H(+)/Mn(2+) exchangers, could not be verified. Potentiometric measurements indicated the manganese-dependent enhancement of transmembrane charge permeation. The origin of high membrane potentials in the presence of manganese, as well as the strongly elevated membrane conductivity with concomitant increase in effectiveness of an uncoupler, suggest a different origin of charge transfer under these conditions. The mode of antibacterial action of hop ionophores can be described as proton ionophores of class I/II, which are capable transporting protons within a wide range of pH due to their inherent complexity of chemical composition. However, growth challenges in the presence of both types of ionophore classes in combination with the measured unusual high BLM potentials in the presence of manganese and at low pH indicate an additional mechanism of inhibition by hop compounds. The latter may be due to the nature/properties of hop compounds, which are known to be highly reactive substances. As a consequence, hop resistance of bacteria can be described as multiple resistance to a heterogeneous mixture of compounds comprising different known and yet unknown charge transport mechanisms, which were dependent on several factors, for example, compound concentrations, cation composition, and pH value. Thus, only specialists such as some L. brevis strains, which can cope with unusually low intracellular manganese levels, can survive hop stress. Accordingly, cross

  2. Range and energetics of charge hopping in organic semiconductors

    Science.gov (United States)

    Abdalla, Hassan; Zuo, Guangzheng; Kemerink, Martijn

    2017-12-01

    The recent upswing in attention for the thermoelectric properties of organic semiconductors (OSCs) adds urgency to the need for a quantitative description of the range and energetics of hopping transport in organic semiconductors under relevant circumstances, i.e., around room temperature (RT). In particular, the degree to which hops beyond the nearest neighbor must be accounted for at RT is still largely unknown. Here, measurements of charge and energy transport in doped OSCs are combined with analytical modeling to reach the univocal conclusion that variable-range hopping is the proper description in a large class of disordered OSC at RT. To obtain quantitative agreement with experiment, one needs to account for the modification of the density of states by ionized dopants. These Coulomb interactions give rise to a deep tail of trap states that is independent of the material's initial energetic disorder. Insertion of this effect into a classical Mott-type variable-range hopping model allows one to give a quantitative description of temperature-dependent conductivity and thermopower measurements on a wide range of disordered OSCs. In particular, the model explains the commonly observed quasiuniversal power-law relation between the Seebeck coefficient and the conductivity.

  3. Collision-based mechanics of bipedal hopping

    National Research Council Canada - National Science Library

    Gutmann, Anne K; Lee, David V; McGowan, Craig P

    2013-01-01

    .... Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers can only elastically store...

  4. Variable-range hopping conductivity in Lu-doped Bi2Te3

    Science.gov (United States)

    Ivanov, Oleg; Yaprintsev, Maxim

    2018-02-01

    The Seebeck coefficient enhancement due to an increase of density-of-states effective mass of electron has been found in n-type Bi1.9Lu0.1Te3. This enhancement is assumed to be related to forming the narrow and non-parabolic impurity (Lu) band with local maximum of electronic density of states lying near the Fermi level. Minimum in the specific electrical resistivity, ρ, originated from change of conductivity mechanism was observed at temperature Tm ≈ 11 K. Above Tm, the ρ change is due to decrease of electron mobility via acoustic phonon scattering. Below Tm, the variable-range hopping conductivity takes place. The electron hops between the localized states of the impurity energy band occur via tunneling process. Using the temperature and magnetic field dependences of ρ, the localization radius of electron was estimated as ≈6 nm. Two parts in the magnetic field dependence of the electrical resistivity were found at temperature of 2 K. At weak magnetic fields, the ρ change is in agreement with the variable-range hopping conductivity mechanism. At high magnetic fields, the positive and almost linear transverse and longitudinal magnetoresistances were observed at low temperatures. Both variable-range hopping conductivity and positive linear magnetoresistance are characteristics of disordered and inhomogeneous semiconductors.

  5. Electrical and thermoelectric transport by variable range hopping in reduced graphene oxide

    Science.gov (United States)

    Park, Min; Hong, Sung Ju; Kim, Kyung Ho; Kang, Hojin; Lee, Minwoo; Jeong, Dae Hong; Park, Yung Woo; Kim, Byung Hoon

    2017-10-01

    This study investigated the transport properties of single-layer reduced graphene oxides (rGOs). The rGOs were prepared by the bubble deposition method followed by thermal reduction. The crossover of the transport mechanism from Efros-Shklovskii (ES) variable range hopping (VRH) between the localized states to Mott-VRH was observed near 70 K using the temperature-dependent conductance. The ES-VRH conduction below 70 K is apparent in the electric field dependence of the field-driven hopping transport in the high-electric field regime. We also figure out that the thermoelectric power is consistent with the 2D Mott VRH above 70 K. We argue that the VRH conduction results from the topological disorders of rGO as confirmed by Raman spectroscopy. This infers that the average distance between defects is approximately 2.0 nm.

  6. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

    Science.gov (United States)

    Piraneo, Tara G; Bull, Jon; Morales, Mariany A; Lavine, Laura C; Walsh, Douglas B; Zhu, Fang

    2015-12-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies.

  7. Hopping conduction mechanism of Pr1-xNdxMnO3 (x=0.3,0.5,0.7)

    Science.gov (United States)

    Biswas, Sanjay; Pal, Sudipta

    2017-05-01

    The temperature dependences of DC electrical resistivity (ρ) of Pr1-xNdxMnO3 (x=0.3, 0.5, 0.7) have been studied in the temperature range from 115K up to 390 K. The samples were prepared by solid state reaction method. In the measured temperature range the resistivity decreases with increasing temperature for all the samples, indicating semiconductor-like behaviour. In the high temperature region, the electrical conduction follows small polaron hopping (SPH) mechanism showing exponential variation of resistivity with temperature. The activation energy decreases with Nd concentration. The low temperature resistivity data follows Mott's ln(ρT -1/2) ˜ T -1/4 law of VRH conduction mechanism. The estimated values of hopping distances (R) and hopping energies (W) of the samples start to decrease with increasing Nd concentrations. The effect of rare earth site doping on the hopping mechanism have been discussed.

  8. Variable range hopping in TiO2 insulating layers for oxide electronic devices

    Directory of Open Access Journals (Sweden)

    Y. L. Zhao

    2012-03-01

    Full Text Available TiO2 thin films are of importance in oxide electronics, e.g., Pt/TiO2/Pt for memristors and Co-TiO2/TiO2/Co-TiO2 for spin tunneling devices. When such structures are deposited at a variety of oxygen pressures, how does TiO2 behave as an insulator? We report the discovery of an anomalous resistivity minimum in a TiO2 film at low pressure (not strongly dependent on deposition temperature. Hall measurements rule out band transport and in most of the pressure range the transport is variable range hopping (VRH though below 20 K it was difficult to differentiate between Mott and Efros-Shklovskii's (ES mechanism. Magnetoresistance (MR of the sample with lowest resistivity was positive at low temperature (for VRH but negative above 10 K indicating quantum interference effects.

  9. Wheeled hopping robot

    Science.gov (United States)

    Fischer, Gary J [Albuquerque, NM

    2010-08-17

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  10. Application of time-hopping UWB range-bit rate performance in the UWB sensor networks

    NARCIS (Netherlands)

    Nascimento, J.R.V. do; Nikookar, H.

    2008-01-01

    In this paper, the achievable range-bit rate performance is evaluated for Time-Hopping (TH) UWB networks complying with the FCC outdoor emission limits in the presence of Multiple Access Interference (MAI). Application of TH-UWB range-bit rate performance is presented for UWB sensor networks.

  11. Variable-range electron hopping, conductivity cross-over and space-charge relaxation in C60Br6

    OpenAIRE

    Manesh, Zachariah; Romanini, Michela; Zygouri, Panagiota; Gournis, Dimitrios; Tamarit Mur, José Luis; Barrio Casado, María del; Macovez, Roberto

    2016-01-01

    Dielectric spectroscopy is employed to probe the frequency-dependent conductivity and dipolar dielectric response of solid C60Br6. Below approximately 215 K, charge conduction is electronic and well described by Mott's variable-range polaron hopping model, with effective hopping activation energy Ea varying between 0.12 eV at 125 K and 0.16 eV at 220 K, and most probable hopping range varying between 100 and 125% of the decay length of the localized polaron's wavefunction. Above 215 K a new c...

  12. Exact solution of the infinite-range-hopping Bose-Hubbard model

    CERN Document Server

    Bru, J B

    2003-01-01

    The thermodynamic behavior of the Bose-Hubbard model is solved for any temperature and any chemical potential. It is found that there is a range of critical coupling strengths $\\lambda_{c1} < \\lambda_{c2} < \\lambda_{c3} < \\dots $ in this model. For coupling strengths between $\\lambda_{c,k}$ and $% \\lambda_{c,k+1}$, Bose-Einstein condensation is suppressed at densities near the integer values $\\rho = 1, \\dots, k$ with an energy gap. This is known as a Mott insulator phase and was previously shown only for zero temperature. In the context of ultra-cold atoms, this phenomenon was experimentally observed in 2002 \\cite{BoseCondInsulator1} but, in the Bose-Hubbard model, it manifests itself also in the pressure-volume diagram at high pressures. It is suggested that this phenomenon persists for finite-range hopping and might also be experimentally observable.

  13. An adaptive resource control mechanism in multi-hop ad-hoc networks

    NARCIS (Netherlands)

    Yang, Y.; Heijenk, Geert; Haverkort, Boudewijn R.H.M.; Masip Bruin, Xavier; Verchere, Dominique; Tsaoussidis, Vassilis; Yannuzzi, Marcelo

    This paper presents an adaptive resource control mechanism for multi-hop ad-hoc network systems, which avoids bottleneck problems caused by the node-fairness property of IEEE 802.11. In our proposal, the feedback information from the downstream bottleneck, derived from Request-To-Send (RTS) and

  14. Poole-Frenkel effect and variable-range hopping conduction in metal/YBCO resistive switching devices

    Science.gov (United States)

    Schulman, A.; Lanosa, L. F.; Acha, C.

    2015-07-01

    Current-voltage (IV) characteristics and the temperature dependence of the contact resistance [R(T)] of Au/YBa2Cu3O7-δ (optimally doped YBCO) interfaces have been studied at different resistance states. These states were produced by resistive switching after accumulating cyclic electrical pulses of increasing number and voltage amplitude. The IV characteristics and the R(T) dependence of the different states are consistent with a Poole-Frenkel (P-F) emission mechanism with trapping-energy levels Et in the 0.06-0.11 eV range. Et remains constant up to a number-of-pulses-dependent critical voltage and increases linearly with a further increase in the voltage amplitude of the pulses. The observation of a P-F mechanism reveals the existence of an oxygen-depleted layer of YBCO near the interface. A simple electrical transport scenario is discussed, where the degree of disorder, the trap energy level, and the temperature range determine an electrical conduction dominated by non-linear effects, either in a P-F emission or in a variable-range hopping regime.

  15. A Multi-hop Topology Control Based on Inter-node Range Measurement for Wireless Sensor Networks Node Localization

    Directory of Open Access Journals (Sweden)

    Ali Husein ALASIRY

    2011-10-01

    Full Text Available In centralized range-based localization techniques, sufficiency of inter-node range information received by the base station strongly affects node position estimation results. Successful data aggregation is influenced by link stability of each connection of routes, especially in a multi-hop topology model. In general, measuring the inter-node range is only performed for position determination purposes. This research introduces the use of inter-node range measurement information for link selection in a multi-hop route composition in order to increase the rate of data aggregation. Due to irregularity problems of wireless media, two areas of node communication have been considered. The regular communication area is the area in which other nodes are able to perform symmetrical communication to the node without failure. The irregular area is the area in which other nodes are seldom able to communicate. Due to its instability, some existing methods tried to avoid the irregular area completely. The proposed method, named Virtual Boundaries (VBs prioritizes these areas. The regular communication area’s nodes have high priority to be selected as link vertices; however, when there is no link candidate inside this area, nodes within the irregular area will be selected with respect to their range to the parent node. This technique resulted in a more robust multi-hop topology that can reduce isolated node numbers and increase the percentage of data collected by the base station accordingly.

  16. Effect of long-range hopping on Tc in a two-dimensional Hubbard-Holstein model of the cuprates

    Science.gov (United States)

    Khatami, E.; Macridin, A.; Jarrell, M.

    2008-08-01

    We study the effect of long-range hoppings on Tc for the two-dimensional (2D) Hubbard model with and without Holstein phonons using parameters evaluated from band-structure calculations for cuprates. Employing the dynamical cluster approximation (DCA) with a quantum Monte Carlo (QMC) cluster solver for a 4-site cluster, we observe that without phonons, the long-range hoppings, t' and t″ , generally suppress Tc . We argue that this trend remains valid for larger clusters. In the presence of the Holstein phonons, a finite t' enhances Tc in the under-doped region for the hole-doped system, consistent with local-density approximation (LDA) calculations and experiment. This is interpreted through the suppression of antiferromagnetic (AF) correlations and the interplay between polaronic effects and the antiferromagnetism.

  17. Possible half-metallicity and variable range hopping transport in Sb-substituted Fe2TiSn Heusler alloys

    Science.gov (United States)

    Chaudhuri, S.; Bhobe, P. A.; Nigam, A. K.

    2018-01-01

    The investigation of the magnetotransport properties on Fe2 TiSn1-x Sb x with 0 ≤slant x ≤slant 0.6 are presented in this paper. The substitution of Sb in place of Sn decreases the anti-site disorder as evident from x-ray diffraction patterns as well as from transport properties measurement. The much-disputed upturn in low temperature electrical resistivity of Fe2 TiSn has been demonstrated to be a result of weak localization induced by anti-site disorder. With increased Sb substitution (⩾25%) the metallic transport behavior of Fe2 TiSn changes to semiconductor-like. At low temperature, carrier transport in such compositions occurs via the variable range hopping mechanism. Moreover, a systematic increase in the anomalous Hall voltage is observed with increasing Sb-content, attributable to a side jump or Berry phase curvature effect. Electrical resistivity in the entire temperature regime hints towards half metallicity of the system. Our ab initio electronic structure calculations using generalised gradient approximation formalism further supports the results of our magnetotransport study.

  18. Robust tilt and lock mechanism for hopping actuator

    Energy Technology Data Exchange (ETDEWEB)

    Salton, Jonathan R.; Buerger, Stephen; Dullea, Kevin J.; Marron, Lisa C.; Salisbury, Curt Michael; Spletzer, Barry Louis

    2017-02-07

    A tilt and lock apparatus that includes a tilt servomechanism, a spiral torsion spring, a lock wheel, and a lock hook is described herein. The spiral torsion spring is mechanically coupled to the tilt servomechanism and the lock wheel (which includes an opening). When a shaft is positioned through the opening, rotation of the lock wheel is in unison with rotation of the shaft. An external surface of the lock wheel includes one or more grooves. The lock hook includes a head that engages and disengages the grooves. The lock wheel is stationary when the head engages one of the grooves and is rotatable when the head disengages the grooves. The head and the grooves are geometrically aligned when engaged to prevent creation of a force that acts to disengage the head responsive to an applied force acting on the shaft.

  19. Musculoskeletal modelling deconstructs the paradoxical effects of elastic ankle exoskeletons on plantar-flexor mechanics and energetics during hopping

    OpenAIRE

    Farris, Dominic James; Hicks, Jennifer L.; Delp, Scott L.; Sawicki, Gregory S.

    2014-01-01

    Experiments have shown that elastic ankle exoskeletons can be used to reduce ankle joint and plantar-flexor muscle loading when hopping in place and, in turn, reduce metabolic energy consumption. However, recent experimental work has shown that such exoskeletons cause less favourable soleus (SO) muscle–tendon mechanics than is observed during normal hopping, which might limit the capacity of the exoskeleton to reduce energy consumption. To directly link plantar-flexor mechanics and energy con...

  20. A Study on Coexistence Capability Evaluations of the Enhanced Channel Hopping Mechanism in WBANs

    Science.gov (United States)

    Wei, Zhongcheng; Sun, Yongmei; Ji, Yuefeng

    2017-01-01

    As an important coexistence technology, channel hopping can reduce the interference among Wireless Body Area Networks (WBANs). However, it simultaneously brings some issues, such as energy waste, long latency and communication interruptions, etc. In this paper, we propose an enhanced channel hopping mechanism that allows multiple WBANs coexisted in the same channel. In order to evaluate the coexistence performance, some critical metrics are designed to reflect the possibility of channel conflict. Furthermore, by taking the queuing and non-queuing behaviors into consideration, we present a set of analysis approaches to evaluate the coexistence capability. On the one hand, we present both service-dependent and service-independent analysis models to estimate the number of coexisting WBANs. On the other hand, based on the uniform distribution assumption and the additive property of Possion-stream, we put forward two approximate methods to compute the number of occupied channels. Extensive simulation results demonstrate that our estimation approaches can provide an effective solution for coexistence capability estimation. Moreover, the enhanced channel hopping mechanism can significantly improve the coexistence capability and support a larger arrival rate of WBANs. PMID:28098818

  1. A Study on Coexistence Capability Evaluations of the Enhanced Channel Hopping Mechanism in WBANs.

    Science.gov (United States)

    Wei, Zhongcheng; Sun, Yongmei; Ji, Yuefeng

    2017-01-14

    As an important coexistence technology, channel hopping can reduce the interference among Wireless Body Area Networks (WBANs). However, it simultaneously brings some issues, such as energy waste, long latency and communication interruptions, etc. In this paper, we propose an enhanced channel hopping mechanism that allows multiple WBANs coexisted in the same channel. In order to evaluate the coexistence performance, some critical metrics are designed to reflect the possibility of channel conflict. Furthermore, by taking the queuing and non-queuing behaviors into consideration, we present a set of analysis approaches to evaluate the coexistence capability. On the one hand, we present both service-dependent and service-independent analysis models to estimate the number of coexisting WBANs. On the other hand, based on the uniform distribution assumption and the additive property of Possion-stream, we put forward two approximate methods to compute the number of occupied channels. Extensive simulation results demonstrate that our estimation approaches can provide an effective solution for coexistence capability estimation. Moreover, the enhanced channel hopping mechanism can significantly improve the coexistence capability and support a larger arrival rate of WBANs.

  2. Molecular mechanisms behind the antimicrobial activity of hop iso-α-acids in Lactobacillus brevis.

    Science.gov (United States)

    Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

    2015-04-01

    The main bittering component in beer, hop iso-α-acids, have been characterised as weak acids, which act as ionophores impairing microbial cells' function under acidic conditions as present in beer. Besides medium pH, divalent cations play a central role regarding the efficacy of the antimicrobial effect. The iso-α-acids' non-bitter derivatives humulinic acids can be found in isomerised hop extracts and can be generated during hop storage. Therefore, they have been under investigation concerning their influence on beer sensory properties. This study sketches the molecular mechanism behind iso-α-acids' antimicrobial activity in Lactobacillus (L.) brevis regarding their ionophore activity versus the dependence of the inhibitory potential on manganese binding, and suggests humulinic acids as novel tasteless food preservatives. We designed and synthesised chemically modified iso-α-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-α-acids. It could be observed that a manganese-binding dependent transmembrane redox reaction (oxidative stress) plays a crucial role in inhibition. Privation of an acidic hydroxyl group neither erased ionophore activity, nor did it entirely abolish antimicrobial activity. Humulinic acids proved to be highly inhibitory, even outperforming iso-α-acids. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. The mesoscopic conductance of disordered rings, its random matrix theory and the generalized variable range hopping picture

    Energy Technology Data Exchange (ETDEWEB)

    Stotland, Alexander; Peer, Tal; Cohen, Doron [Department of Physics, Ben-Gurion University, Beer-Sheva 84005 (Israel); Budoyo, Rangga; Kottos, Tsampikos [Department of Physics, Wesleyan University, Middletown, CT 06459 (United States)

    2008-07-11

    The calculation of the conductance of disordered rings requires a theory that goes beyond the Kubo-Drude formulation. Assuming 'mesoscopic' circumstances the analysis of the electro-driven transitions shows similarities with a percolation problem in energy space. We argue that the texture and the sparsity of the perturbation matrix dictate the value of the conductance, and study its dependence on the disorder strength, ranging from the ballistic to the Anderson localization regime. An improved sparse random matrix model is introduced to capture the essential ingredients of the problem, and leads to a generalized variable range hopping picture. (fast track communication)

  4. Mechanisms of resistance to three mite growth inhibitors of Tetranychus urticae in hops.

    Science.gov (United States)

    Adesanya, A W; Morales, M A; Walsh, D B; Lavine, L C; Lavine, M D; Zhu, F

    2018-02-01

    Mite growth inhibitors (MGIs), such as etoxazole and hexythiazox, are valuable IPM tools for Tetranychus urticae control in hops due to their unique mode of action and selectivity. Hence, it is necessary to standardize bioassay methods to evaluate the efficacy of MGIs, monitor resistance, and identify mechanisms underlying MGI resistance in the field. Here, we developed a three-tiered approach for evaluating ovicidal toxicity of MGIs to T. urticae, which simulated different MGI exposure scenarios in the field. The most effective bioassay method was direct exposure of T. urticae eggs to MGIs. With this method, four field-collected T. urticae populations showed low-to-moderate resistance to MGIs. Cross-resistance among MGIs and from MGIs to bifenazate and bifenthrin was detected. Besides target site insensitivity, enhanced cytochrome P450 and esterase activities also contribute to the MGI resistance in hop yard-collected T. urticae populations. Low-to-moderate MGI resistance in T. urticae populations may be mediated by multiple mechanisms. Positive selection pressure on the I1017F mutation is moderate in field-collected T. urticae populations. Further studies are required to identify metabolic detoxification genes that confer resistance to MGIs for precise resistance monitoring.

  5. Transparent wide band gap crystals follow indirect allowed transition and bipolaron hopping mechanism

    Directory of Open Access Journals (Sweden)

    Feroz A. Mir

    2014-01-01

    Full Text Available Recently, we carried out structural, optical and dielectric studies on micro-crystals of Oxypeucedanin (C16H14O5, isolated from the roots of plant Prangos pabularia (Mir et al. (2014 [3,4]. The obtained trend in frequency exponent (s with frequency (ω indicates that the universal dynamic response is followed by this compound. From optical absorption spectroscopy, the optical band gap (Eg was estimated around 3.76 eV and system is showing indirect allowed transition. Using Eg in certain relation of s, a close value of s (as much close obtained by fitting ac conductivity was obtained. This method was further used for other similar systems and again same trend was obtained. So a general conclusion was made that the high transmitting wide band insulators or semiconductors may follow bipolaron hopping transport mechanism.

  6. Investigation of hopped frequency waveforms for range and velocity measurements of radar targets

    CSIR Research Space (South Africa)

    Kathree, U

    2015-10-01

    Full Text Available In the field of radar, High Range Resolution (HRR) profiles are often used to improve target tracking accuracy in range and to allow the radar system to produce an image of an object using techniques such as inverse synthetic aperture radar (ISAR...

  7. Clathrin-dependent mechanisms modulate the subcellular distribution of class C Vps/HOPS tether subunits in polarized and nonpolarized cells.

    Science.gov (United States)

    Zlatic, Stephanie A; Tornieri, Karine; L'Hernault, Steven W; Faundez, Victor

    2011-05-15

    Coats define the composition of carriers budding from organelles. In addition, coats interact with membrane tethers required for vesicular fusion. The yeast AP-3 (Adaptor Protein Complex 3) coat and the class C Vps/HOPS (HOmotypic fusion and Protein Sorting) tether follow this model as their interaction occurs at the carrier fusion step. Here we show that mammalian Vps class C/HOPS subunits and clathrin interact and that acute perturbation of clathrin function disrupts the endosomal distribution of Vps class C/HOPS tethers in HEK293T and polarized neuronal cells. Vps class C/HOPS subunits and clathrin exist in complex with either AP-3 or hepatocyte growth factor receptor substrate (Hrs). Moreover, Vps class C/HOPS proteins cofractionate with clathrin-coated vesicles, which are devoid of Hrs. Expression of FK506 binding protein (FKBP)-clathrin light chain chimeras, to inhibit clathrin membrane association dynamics, increased Vps class C/HOPS subunit content in rab5 endosomal compartments. Additionally, Vps class C/HOPS subunits were concentrated at tips of neuronal processes, and their delivery was impaired by expression of FKBP-clathrin chimeras and AP20187 incubation. These data support a model in which Vps class C/HOPS subunits incorporate into clathrin-coated endosomal domains and carriers in mammalian cells. We propose that vesicular (AP-3) and nonvesicular (Hrs) clathrin mechanisms segregate class C Vps/HOPS tethers to organelles and domains of mammalian cells bearing complex architectures.

  8. Thermally assisted variable range hopping in Tl4S3Se crystal

    Indian Academy of Sciences (India)

    electrical parameters that are necessary for the construction of electronic devices like absorption layers in solar cells. This proposed model is also used to explain the conduction mechanism and .... The details of this theory are clearly discussed in the study by Abtew et al.9 In the current study, it is sufficient to recall that the ...

  9. Poole-Frenkel effect and Variable-Range Hopping conduction in metal / YBCO resistive switching devices

    OpenAIRE

    Schulman, Alejandro; Lanosa, Leandro F.; Acha, Carlos

    2015-01-01

    Current-voltage (IV) characteristics and the temperature dependence of the contact resistance [$R(T)$] of Au / YBa$_2$Cu$_3$O$_{7-\\delta}$ (optimally doped YBCO) interfaces have been studied at different resistance states. This states were produced by resistive switching after accumulating cyclic electrical pulses of increasing number and voltage amplitude. The IV characteristics and the $R(T)$ dependence of the different states are consistent with a Poole-Frenkel (P-F) emission mechanism wit...

  10. Mode-hopping mechanism generating colored noise in a magnetic tunnel junction based spin torque oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Raghav [Department of Physics, Indian Institute of Technology, Delhi, New Delhi 110016 (India); Dürrenfeld, P.; Iacocca, E. [Department of Physics, University of Gothenburg, Gothenburg 412 96 (Sweden); Heinonen, O. G. [Argonne National Laboratory, Materials Science Division, Lemont, Illinois 60439 (United States); Åkerman, J. [Department of Physics, University of Gothenburg, Gothenburg 412 96 (Sweden); Materials Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, Kista 164 40 (Sweden); Muduli, P. K. [Department of Physics, Indian Institute of Technology, Delhi, New Delhi 110016 (India); Department of Physics, University of Gothenburg, Gothenburg 412 96 (Sweden)

    2014-09-29

    The frequency noise spectrum of a magnetic tunnel junction based spin torque oscillator is examined where multiple modes and mode-hopping events are observed. The frequency noise spectrum is found to consist of both white noise and 1/f frequency noise. We find a systematic and similar dependence of both white noise and 1/f frequency noise on bias current and the relative angle between the reference and free layers, which changes the effective damping and hence the mode-hopping behavior in this system. The frequency at which the 1/f frequency noise changes to white noise increases as the free layer is aligned away from the anti-parallel orientation w.r.t the reference layer. These results indicate that the origin of 1/f frequency noise is related to mode-hopping, which produces both white noise as well as 1/f frequency noise similar to the case of ring lasers.

  11. Spring-like leg behaviour, musculoskeletal mechanics and control in maximum and submaximum height human hopping

    OpenAIRE

    Bobbert, Maarten F; Richard Casius, L. J.

    2011-01-01

    The purpose of this study was to understand how humans regulate their ‘leg stiffness’ in hopping, and to determine whether this regulation is intended to minimize energy expenditure. ‘Leg stiffness’ is the slope of the relationship between ground reaction force and displacement of the centre of mass (CM). Variations in leg stiffness were achieved in six subjects by having them hop at maximum and submaximum heights at a frequency of 1.7 Hz. Kinematics, ground reaction forces and electromyogram...

  12. Spring-like leg behaviour, musculoskeletal mechanics and control in maximum and submaximum height human hopping

    NARCIS (Netherlands)

    Bobbert, M.F.

    2011-01-01

    The purpose of this study was to understand how humans regulate their 'leg stiffness' in hopping, and to determine whether this regulation is intended to minimize energy expenditure. 'Leg stiffness' is the slope of the relationship between ground reaction force and displacement of the centre of mass

  13. Mott and Efros-Shklovskii hopping conductions in porous silicon nanostructures

    Science.gov (United States)

    Islam, Md. Nazrul; Ram, Sanjay K.; Kumar, Satyendra

    2009-05-01

    Electrical conductivity of electrochemically etched porous silicon was studied over a wide temperature range from 15 to 450 K. Applicability of various electrical transport mechanisms has been critically analyzed. While the conductivity data above room temperature shows extended state conduction, lowering the temperature leads to Berthelot-type conduction (180-280 K). Further, Mott's hopping (in the range 140-180 K) and Efros-Shklovskii hopping (below 120 K) conduction are found to be operating in lower temperature ranges. A clear crossover from Mott to Efros-Shklovskii variable range hopping transport is observed at low temperatures.

  14. Exploiting elasticity: Modeling the influence of neural control on mechanics and energetics of ankle muscle-tendons during human hopping.

    Science.gov (United States)

    Robertson, Benjamin D; Sawicki, Gregory S

    2014-07-21

    We present a simplified Hill-type model of the human triceps surae-Achilles tendon complex working on a gravitational-inertial load during cyclic contractions (i.e. vertical hopping). Our goal was to determine the role that neural control plays in governing muscle, or contractile element (CE), and tendon, or series elastic element (SEE), mechanics and energetics within a compliant muscle-tendon unit (MTU). We constructed a 2D parameter space consisting of many combinations of stimulation frequency and magnitude (i.e. neural control strategies). We compared the performance of each control strategy by evaluating peak force and average positive mechanical power output for the system (MTU) and its respective components (CE, SEE), force-length (F-L) and -velocity (F-V) operating point of the CE during active force production, average metabolic rate for the CE, and both MTU and CE apparent efficiency. Our results suggest that frequency of stimulation plays a primary role in governing whole-MTU mechanics. These include the phasing of both activation and peak force relative to minimum MTU length, average positive power, and apparent efficiency. Stimulation amplitude was primarily responsible for governing average metabolic rate and within MTU mechanics, including peak force generation and elastic energy storage and return in the SEE. Frequency and amplitude of stimulation both played integral roles in determining CE F-L operating point, with both higher frequency and amplitude generally corresponding to lower CE strains, reduced injury risk, and elimination of the need for passive force generation in the CE parallel elastic element (PEE). Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Landing mechanics during single hop for distance in females following anterior cruciate ligament reconstruction compared to healthy controls.

    Science.gov (United States)

    Trigsted, Stephanie M; Post, Eric G; Bell, David R

    2017-05-01

    To determine possible differences in single-hop kinematics and kinetics in females with anterior cruciate ligament reconstruction compared to healthy controls. A second purpose was to make comparisons between the healthy and reconstructed limbs. Subjects were grouped based on surgical status (33 ACLR patients and 31 healthy controls). 3D motion capture synchronized with force plates was used to capture the landing phase of three successful trials of single hop for distance during a single data collection session. Peak values during the loading phase were analysed. Subjects additionally completed three successful trials of the triple hop for distance Tegner activity scale and International Knee Document Committee 2000 (IKDC). Controls demonstrated greater peak knee flexion and greater internal knee extension moment and hip extension moment than ACLR subjects. Within the ACLR group, the healthy limb exhibited greater peak knee flexion, hip flexion, hip extension moment, single hop and triple hops for distance and normalized quadriceps strength. Patients who undergo anterior cruciate ligament reconstruction land in a more extended posture when compared to healthy controls and compared to their healthy limb. III.

  16. Aharonov-Bohm effect in a helical ring with long-range hopping: Effects of Rashba spin-orbit interaction and disorder

    Science.gov (United States)

    Dutta, Paramita; Saha, Arijit; Jayannavar, A. M.

    2016-11-01

    We study the Aharonov-Bohm effect in a two-terminal helical ring with long-range hopping in the presence of Rashba spin-orbit interaction. We explore how the spin polarization behavior changes depending on the applied magnetic flux and the incoming electron energy. The most interesting feature that we articulate in this system is that zero-energy crossings appear in the energy spectra at Φ =0 and also at integer multiples of half-flux quantum values (n Φ0/2 ,n being an integer) of the applied magnetic flux. We investigate the transport properties of the ring using Green's function formalism and find that the zero-energy transmission peaks corresponding to those zero-energy crossings vanish in the presence of Rashba spin-orbit interaction. We also incorporate static random disorder in our system and show that the zero-energy crossings and transmission peaks are not immune to disorder even in the absence of Rashba spin-orbit interaction. The latter prevents the possibility of these helical states in the ring behaving like topological insulator edge states.

  17. [Mechanisms that limit pollinator range in Ericaceae].

    Science.gov (United States)

    Dlusskiĭ, G M; Glazunova, K P; Perfil'eva, K S

    2005-01-01

    Studies were conducted in 2001-2003 at Valdai National Park (Novgorod region) and at the Zvenigorod biological station of Moscow State University. The morphology of flowers, flowering dynamics and composition of insect visiting flowers of Ericaceae species: Andromeda polifolia, Chamaedaphne calyculata, Ledum palustre, Oxycoccus palustris, Vaccinium myrtillus, V. uliginosum, and V. vitis-idaea L. were studied. Some species of insects visiting flowers were excluded from the list of pollinators on the basis of observation on their behavior. L. palustre was visited mainly by flies where as other investigated species were visited mainly by bumblebees. In some cases bumblebees were the only visitors of the investigated plants. Mechanisms that protect flowers from flies and short-tongued solitary bees visits and ensure a best pollination by bumblebees are various among different species of Ericaceae. Efficiency of nectary protection also differs among different plant species and is defined by particularities of their habitats and flowering phenology. As far as all species of this family during the flowering are dominants in typical habitats, a competition for the pollination with species of other families in most cases is megligible. Flowering periods of V. vitis-idaea and V. myrtillus in forest ecosystems overlapped weakly. Moreover, V. myrtillus is pollinated mainly by bumblebee queens where as pollinators of V. vitis-idaea are bumblebee workers, solitary bees and horse flies. The other investigated plant species inhabit only oligotrophic peat bogs. Thery are pollinated by bumblebees but periods of flowering are not overlapped and consequently follow one after another. L. palustre and V. uliginosum flower simultaneosly but they are pollinated by different pollinators.

  18. Parvoviral host range and cell entry mechanisms.

    Science.gov (United States)

    Cotmore, Susan F; Tattersall, Peter

    2007-01-01

    Parvoviruses elaborate rugged nonenveloped icosahedral capsids of approximately 260 A in diameter that comprise just 60 copies of a common core structural polypeptide. While serving as exceptionally durable shells, capable of protecting the single-stranded DNA genome from environmental extremes, the capsid also undergoes sequential conformational changes that allow it to translocate the genome from its initial host cell nucleus all the way into the nucleus of its subsequent host. Lacking a duplex transcription template, the virus must then wait for its host to enter S-phase before it can initiate transcription and usurp the cell's synthetic pathways. Here we review cell entry mechanisms used by parvoviruses. We explore two apparently distinct modes of host cell specificity, first that used by Minute virus of mice, where subtle glycan-specific interactions between host receptors and residues surrounding twofold symmetry axes on the virion surface mediate differentiated cell type target specificity, while the second involves novel protein interactions with the canine transferrin receptor that allow a mutant of the feline leukopenia serotype, Canine parvovirus, to bind to and infect dog cells. We then discuss conformational shifts in the virion that accompany cell entry, causing exposure of a capsid-tethered phospholipase A2 enzymatic core that acts as an endosomolytic agent to mediate virion translocation across the lipid bilayer into the cell cytoplasm. Finally, we discuss virion delivery into the nucleus, and consider the nature of transcriptionally silent DNA species that, escaping detection by the cell, might allow unhampered progress into S-phase and hence unleash the parvoviral Trojan horse.

  19. The Formation of "Hip-Hop Academicus"--How American Scholars Talk about the Academisation of Hip-Hop

    Science.gov (United States)

    Soderman, Johan

    2013-01-01

    Social activism and education have been associated with hip-hop since it emerged in New York City 38 years ago. Therefore, it might not be surprising that universities have become interested in hip-hop. This article aims to highlight this "hip-hop academisation" and analyse the discursive mechanisms that manifest in these academisation…

  20. Involvement of Vacuolar Sequestration and Active Transport in Tolerance of Saccharomyces cerevisiae to Hop Iso-α-Acids▿ † ¶

    Science.gov (United States)

    Hazelwood, Lucie A.; Walsh, Michael C.; Pronk, Jack T.; Daran, Jean-Marc

    2010-01-01

    The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop α-acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso-α-acids have hitherto been restricted to lactic acid bacteria. The present study investigated molecular mechanisms of hop iso-α-acid resistance in the model eukaryote Saccharomyces cerevisiae. Growth inhibition occurred at concentrations of hop iso-α-acids that were an order of magnitude higher than those found with hop-tolerant prokaryotes. Chemostat-based transcriptome analysis and phenotype screening of the S. cerevisiae haploid gene deletion collection were used as complementary methods to screen for genes involved in hop iso-α-acid detoxification and tolerance. This screening and further analysis of deletion mutants confirmed that yeast tolerance to hop iso-α-acids involves three major processes, active proton pumping into the vacuole by the vacuolar-type ATPase to enable vacuolar sequestration of iso-α-acids and alteration of cell wall structure and, to a lesser extent, active export of iso-α-acids across the plasma membrane. Furthermore, iso-α-acids were shown to affect cellular metal homeostasis by acting as strong zinc and iron chelators. PMID:19915041

  1. Local-hopping mechanism of the O2- vacancy in stabilized ZrO2 studied by measuring the integrated intensity of quasieleastic light scattering

    Science.gov (United States)

    Nakajima, A.; Shin, S.; Kawaharada, I.; Ishigame, M.

    1994-06-01

    A method for estimating the concentration of quasielastic-light-scattering (QELS) centers is developed and a decrease of the concentration of scattering centers in stabilized ZrO2 is observed at high temperatures. The hopping mechanism of the O-2 ion in the yttrium-stabilized ZrO2 is investigated in detail by measuring the integrated intensity and the fixed frequency intensity of the QELS. The observed polarization character and temperature dependence of QELS are interpreted by three kinds of clusters as QELS. From the polarization characters and association energy of the clusters, the QELS centers for depolarized light are found to be the clusters which contain one O2- vacancy and two next- and/or third-nearest-neighbor Y3+ ions and the QELS centers for polarized light to be the clusters above and the cluster which contains one O2- vacancy and two nearest-neighbor Y3+ ions.

  2. Nerve Conduction Through Dendrites via Proton Hopping.

    Science.gov (United States)

    Kier, Lemont B

    2017-01-01

    In our previous studies of nerve conduction conducted by proton hopping, we have considered the axon, soma, synapse and the nodes of Ranvier. The role of proton hopping described the passage of information through each of these units of a typical nerve system. The synapse projects information from the axon to the dendrite and their associated spines. We have invoked the passage of protons via a hopping mechanism to illustrate the continuum of the impulse through the system, via the soma following the dendrites. This is proposed to be a continuum invoked by the proton hopping method. With the proposal of the activity through the dendrites, via proton hopping, a complete model of the nerve function is invoked. At each step to the way, a water pathway is present and is invoked in the proposed model as the carrier of the message via proton hopping. The importance of the dendrites is evident by the presence of a vast number of spines, each possessing the possibility to carry unique messages through the nervous system. With this model of the role of dendrites, functioning with the presence of proton hopping, a complete model of the nerve system is presented. The validity of this model will be available for further studies and models to assess it's validity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Hopping Robot with Wheels

    Science.gov (United States)

    Barlow, Edward; Marzwell, Nevellie; Fuller, Sawyer; Fionni, Paolo; Tretton, Andy; Burdick, Joel; Schell, Steve

    2003-01-01

    A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot described in "Minimally Actuated Hopping Robot" (NPO- 20911), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 50. There are many potential applications for robots with hopping and wheeled-locomotion (roving) capabilities in diverse fields of endeavor, including agriculture, search-and-rescue operations, general military operations, removal or safe detonation of land mines, inspection, law enforcement, and scientific exploration on Earth and remote planets. The combination of hopping and roving enables this robot to move rapidly over very rugged terrain, to overcome obstacles several times its height, and then to position itself precisely next to a desired target. Before a long hop, the robot aims itself in the desired hopping azimuth and at a desired takeoff angle above horizontal. The robot approaches the target through a series of hops and short driving operations utilizing the steering wheels for precise positioning.

  4. Modulation of neuronal dynamic range using two different adaptation mechanisms

    Science.gov (United States)

    Wang, Lei; Wang, Ye; Fu, Wen-long; Cao, Li-hong

    2017-01-01

    The capability of neurons to discriminate between intensity of external stimulus is measured by its dynamic range. A larger dynamic range indicates a greater probability of neuronal survival. In this study, the potential roles of adaptation mechanisms (ion currents) in modulating neuronal dynamic range were numerically investigated. Based on the adaptive exponential integrate-and-fire model, which includes two different adaptation mechanisms, i.e. subthreshold and suprathreshold (spike-triggered) adaptation, our results reveal that the two adaptation mechanisms exhibit rather different roles in regulating neuronal dynamic range. Specifically, subthreshold adaptation acts as a negative factor that observably decreases the neuronal dynamic range, while suprathreshold adaptation has little influence on the neuronal dynamic range. Moreover, when stochastic noise was introduced into the adaptation mechanisms, the dynamic range was apparently enhanced, regardless of what state the neuron was in, e.g. adaptive or non-adaptive. Our model results suggested that the neuronal dynamic range can be differentially modulated by different adaptation mechanisms. Additionally, noise was a non-ignorable factor, which could effectively modulate the neuronal dynamic range. PMID:28469660

  5. Steerable Hopping Six-Legged Robot

    Science.gov (United States)

    Younse, Paulo; Aghazarian, Hrand

    2010-01-01

    The figure depicts selected aspects of a six-legged robot that moves by hopping and that can be steered in the sense that it can be launched into a hop in a controllable direction. This is a prototype of hopping robots being developed for use in scientific exploration of rough terrain on remote planets that have surface gravitation less than that of Earth. Hopping robots could also be used on Earth, albeit at diminished hopping distances associated with the greater Earth gravitation. The upper end of each leg is connected through two universal joints to an upper and a lower hexagonal frame, such that the tilt of the leg depends on the relative position of the two frames. Two non-back-driveable worm-gear motor drives are used to control the relative position of the two frames along two axes 120 apart, thereby controlling the common tilt of all six legs and thereby, further, controlling the direction of hopping. Each leg includes an upper and a lower aluminum frame segment with a joint between them. A fiberglass spring, connected via hinges to both segments, is used to store hopping energy prior to launch into a hop and to cushion the landing at the end of the hop. A cable for loading the spring is run into each leg through the center of the universal joints and then down along the center lines of the segments to the lower end of the leg. A central spool actuated by a motor with a harmonic drive and an electromagnetic clutch winds in all six cables to compress all six springs (thereby also flexing all six legs) simultaneously. To ensure that all the legs push off and land in the same direction, timing- belt pulley drives are attached to the leg segments, restricting the flexing and extension of all six legs to a common linear motion. In preparation for a hop, the spool can be driven to load the spring legs by an amount corresponding to a desired hop distance within range. The amount of compression can be computed from the reading of a shaft-angle encoder that

  6. Hopping transport in solids

    CERN Document Server

    Pollak, M

    1991-01-01

    The hopping process, which differs substantially from conventional transport processes in crystals, is the central process in the transport phenomena discussed in this book. Throughout the book the term ``hopping'' is defined as the inelastic tunneling transfer of an electron between two localized electronic states centered at different locations. Such processes do not occur in conventional electronic transport in solids, since localized states are not compatible with the translational symmetry of crystals.The rapid growth of interest in hopping transport has followed in the footsteps of the

  7. Effects of prophylactic ankle and knee braces on leg stiffness during hopping.

    Science.gov (United States)

    Hobara, Hiroaki; Hashizume, Satoru; Kobayashi, Yoshiyuki

    2017-01-01

    During human movement, the leg can be represented as a mechanical spring, with its stiffness potentially contributing to sports performance and injury prevention. Although many individuals perform athletic activities with joint stabilizers, little is known about the effects of prophylactic lower extremity braces on leg stiffness. The objective of this study was to investigate the effect of ankle and/or knee braces on leg stiffness measured during one-legged hopping at a range of frequencies. Thirteen male participants performed one-legged hopping with their dominant leg at frequencies of 2.2, 2.6, and 3.0 Hz. All participants were randomly tested under the following four brace conditions: 1) no brace (control), 2) prophylactic ankle brace, 3) prophylactic knee brace, and 4) prophylactic ankle and knee braces. Based on a spring-mass model, leg stiffness was calculated using data from an accelerometer. It was found that leg stiffness increased with increasing hopping frequency for each brace condition. However, there were no significant differences in leg stiffness among the four brace conditions at the three hopping frequencies. Since some level of leg stiffness is needed for optimal athletic performance and training, these results suggest that ankle and knee braces do not significantly interfere with dynamic hopping activities.

  8. Effects of prophylactic ankle and knee braces on leg stiffness during hopping

    Directory of Open Access Journals (Sweden)

    Hobara H

    2017-04-01

    Full Text Available Hiroaki Hobara, Satoru Hashizume, Yoshiyuki Kobayashi Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan Abstract: During human movement, the leg can be represented as a mechanical spring, with its stiffness potentially contributing to sports performance and injury prevention. Although many individuals perform athletic activities with joint stabilizers, little is known about the effects of prophylactic lower extremity braces on leg stiffness. The objective of this study was to investigate the effect of ankle and/or knee braces on leg stiffness measured during one-legged ­hopping at a range of frequencies. Thirteen male participants performed one-legged hopping with their dominant leg at frequencies of 2.2, 2.6, and 3.0 Hz. All participants were randomly tested under the following four brace conditions: 1 no brace (control, 2 prophylactic ankle brace, 3 prophylactic knee brace, and 4 prophylactic ankle and knee braces. Based on a spring–mass model, leg stiffness was calculated using data from an accelerometer. It was found that leg stiffness increased with increasing hopping frequency for each brace condition. However, there were no significant differences in leg stiffness among the four brace conditions at the three hopping frequencies. Since some level of leg stiffness is needed for optimal athletic performance and training, these results suggest that ankle and knee braces do not significantly interfere with dynamic hopping activities. Keywords: spring–mass model, injury prevention, compensatory strategy

  9. Factors of Intensification in the Hops Cluster of Chuvashia

    Science.gov (United States)

    Zakharov, Anatoly I.; Evgrafov, Oleg V.; Zakharov, Dmitry A.; Ivanova, Elena V.; Tolstova, Marija L.; Tsaregorodtsev, Evgeny I.

    2016-01-01

    The complex analysis of development of hop-growing for 1971-2015 is carried out. In the conditions of the field experiment made in the Chuvash Republic hop-growing intensification elements--technology of its cultivation, mechanization are fulfilled. Based on researches it is established that the main internal allowance of increase in efficiency of…

  10. Political Mechanisms for Long-Range Survival and Development

    Science.gov (United States)

    Marshall, W.

    As the first species aware of extinction and capable of proactively ensuring our long-term survival and development, it is striking that we do not do so with the rigor, formality, and foresight it requires. Only from a reactive posture have we responded to the challenges of global warfare, human rights, environmental concerns, and sustainable development. Despite our awareness of the possibility for extinction and apocalyptic set-backs to our evolution, and despite the existence of long-range studies-which must still be dramatically increased-proactive global policy implementation regarding our long-term survival and development is arguably non-existent. This lack of long-term policy making can be attributed in part to the lack of formal political mechanisms to facilitate longer-range policy making that extends 30 years or more into the future. Political mechanisms for infusing long-range thinking, research, and strategic planning into the policy-making process can help correct this shortcoming and provide the motivation needed to adequately address long-term challenges with the political rigor required to effectively establish and implement long-term policies. There are some efforts that attempt to address longer-range issues, but those efforts often do not connect to the political process, do not extend 30 or more years into the future, are not well-funded, and are not sufficiently systemic. Political mechanisms for long-range survival and prosperity could correct these inadequacies by raising awareness, providing funding, and most importantly, leveraging political rigor to establish and enforce long-range strategic planning and policies. The feasibility of such mechanisms should first be rigorously studied and assessed in a feasibility study, which could then inform implementation. This paper will present the case for such a study and suggest some possible political mechanisms that should be investigated further in the proposed study. This work is being further

  11. Two-legged hopping in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Matthew F. Moran

    2013-03-01

    Full Text Available Sensory processing deficits are common within autism spectrum disorders (ASD. Deficits have a heterogeneous dispersion across the spectrum and multimodal processing tasks are thought to magnify integration difficulties. Two-legged hopping in place in sync with an auditory cue (2.3, 3.0 Hz was studied in a group of six individuals with expressive language impaired ASD (ELI-ASD and an age-matched control group. Vertical ground reaction force data were collected and discrete Fourier transforms were utilized to determine dominant hopping cadence. Effective leg stiffness was computed through a mass-spring model representation. The ELI-ASD group were unsuccessful in matching their hopping cadence (2.21±0.30 hops•sec-1, 2.35±0.41 hops•sec-1 to either auditory cue with greater deviations at the 3.0 Hz cue. In contrast, the control group was able to match hopping cadence (2.35±0.06 hops•sec-1, 3.02±0.10 hops•sec-1 to either cue via an adjustment of effective leg stiffness. The ELI-ASD group demonstrated a varied response with an interquartile range (IQR in excess of 0.5 hops•sec-1 as compared to the control group with an IQR < 0.03 hops•sec-1. Several sensorimotor mechanisms could explain the inability of participants with ELI-ASD to modulate motor output to match an external auditory cue. These results suggest that a multimodal gross motor task can (1 discriminate performance among a group of individuals with severe autism, and (2 could be a useful quantitative tool for evaluating motor performance in individuals with ASD individuals.

  12. Hops (Humulus lupulus L. Bitter Acids: Modulation of Rumen Fermentation and Potential As an Alternative Growth Promoter

    Directory of Open Access Journals (Sweden)

    Michael D. Flythe

    2017-08-01

    Full Text Available Antibiotics can improve ruminant growth and efficiency by altering rumen fermentation via selective inhibition of microorganisms. However, antibiotic use is increasingly restricted due to concerns about the spread of antibiotic-resistance. Plant-based antimicrobials are alternatives to antibiotics in animal production. The hops plant (Humulus lupulus L. produces a range of bioactive secondary metabolites, including antimicrobial prenylated phloroglucinols, which are commonly called alpha- and beta-acids. These latter compounds can be considered phyto-ionophores, phytochemicals with a similar antimicrobial mechanism of action to ionophore antibiotics (e.g., monensin, lasalocid. Like ionophores, the hop beta-acids inhibit rumen bacteria possessing a classical Gram-positive cell envelope. This selective inhibition causes several effects on rumen fermentation that are beneficial to finishing cattle, such as decreased proteolysis, ammonia production, acetate: propionate ratio, and methane production. This article reviews the effects of hops and hop secondary metabolites on rumen fermentation, including the physiological mechanisms on specific rumen microorganisms, and consequences for the ruminant host and ruminant production. Further, we propose that hop beta-acids are useful model natural products for ruminants because of (1 the ionophore-like mechanism of action and spectrum of activity and (2 the literature available on the plant due to its use in brewing.

  13. Evidence for a hopping mechanism in metal|single molecule|metal junctions involving conjugated metal–terpyridyl complexes; potential-dependent conductances of complexes [M(pyterpy)2]2+(M = Co and Fe; pyterpy = 4′-(pyridin-4-yl)-2,2′:6′,2′′-terpyridine) in ionic liquid

    DEFF Research Database (Denmark)

    Chappell, Sarah; Brooke, Carly; Nichols, Richard John

    2016-01-01

    Extensive studies of various families of conjugated molecules in metal|molecule|metal junctions suggest that the mechanism of conductance is usually tunnelling for molecular lengths < ca. 4 nm, and that for longer molecules, coherence is lost as a hopping element becomes more significant. In this...... potential in ionic liquid electrolyte, and the conductance–overpotential relationship is found to fit well with the Kuznetsov–Ulstrup relationship, which is essentially a hopping description....

  14. Holstein polarons and triplet bipolarons with NNN hopping

    Science.gov (United States)

    Chakraborty, Monodeep; Taraphder, A.; Berciu, Mona

    2017-05-01

    We study the ground state of 1D Holstein single polaron with next nearest neighbour electron hopping (NNN), employing a variational approximation based on exact diagonalization. Our investigation reveals that, depending upon the sign and magnitude of the NNN hopping integral with respect to nearest neighbour hopping, the polaron band minima may occur at non-zero kGS. We compare the present scenario with the SSH polarons, where a similar feature is also observed, albeit, due to very different mechanism. Our initial investigation of triplet bipolarons, in presence of an attractive extended Hubbard interactions, further substantiates the differences between the present model and the SSH model.

  15. Hip-Hop Education Resources

    Science.gov (United States)

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  16. Immunomodulation by the Pseudomonas syringae HopZ type III effector family in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jennifer D Lewis

    Full Text Available Pseudomonas syringae employs a type III secretion system to inject 20-30 different type III effector (T3SE proteins into plant host cells. A major role of T3SEs is to suppress plant immune responses and promote bacterial infection. The YopJ/HopZ acetyltransferases are a superfamily of T3SEs found in both plant and animal pathogenic bacteria. In P. syringae, this superfamily includes the evolutionarily diverse HopZ1, HopZ2 and HopZ3 alleles. To investigate the roles of the HopZ family in immunomodulation, we generated dexamethasone-inducible T3SE transgenic lines of Arabidopsis for HopZ family members and characterized them for immune suppression phenotypes. We show that all of the HopZ family members can actively suppress various facets of Arabidopsis immunity in a catalytic residue-dependent manner. HopZ family members can differentially suppress the activation of mitogen-activated protein (MAP kinase cascades or the production of reactive oxygen species, whereas all members can promote the growth of non-virulent P. syringae. Localization studies show that four of the HopZ family members containing predicted myristoylation sites are localized to the vicinity of the plasma membrane while HopZ3 which lacks the myristoylation site is at least partially nuclear localized, suggesting diversification of immunosuppressive mechanisms. Overall, we demonstrate that despite significant evolutionary diversification, all HopZ family members can suppress immunity in Arabidopsis.

  17. Involvement of Vacuolar Sequestration and Active Transport in Tolerance of Saccharomyces cerevisiae to Hop Iso-?-Acids

    NARCIS (Netherlands)

    Hazelwood, L.A.; Walsh, M.C.; Pronk, J.T.; Daran, J.M.

    2009-01-01

    The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop -acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso--acids have hitherto been restricted to lactic acid bacteria.

  18. Long-range movement of large mechanically interlocked DNA nanostructures.

    Science.gov (United States)

    List, Jonathan; Falgenhauer, Elisabeth; Kopperger, Enzo; Pardatscher, Günther; Simmel, Friedrich C

    2016-08-05

    Interlocked molecules such as catenanes and rotaxanes, connected only via mechanical bonds have the ability to perform large-scale sliding and rotational movements, making them attractive components for the construction of artificial molecular machines and motors. We here demonstrate the realization of large, rigid rotaxane structures composed of DNA origami subunits. The structures can be easily modified to carry a molecular cargo or nanoparticles. By using multiple axle modules, rotaxane constructs are realized with axle lengths of up to 355 nm and a fuel/anti-fuel mechanism is employed to switch the rotaxanes between a mobile and a fixed state. We also create extended pseudo-rotaxanes, in which origami rings can slide along supramolecular DNA filaments over several hundreds of nanometres. The rings can be actively moved and tracked using atomic force microscopy.

  19. Geometry can provide long-range mechanical guidance for embryogenesis.

    Directory of Open Access Journals (Sweden)

    Mahamar Dicko

    2017-03-01

    Full Text Available Downstream of gene expression, effectors such as the actomyosin contractile machinery drive embryo morphogenesis. During Drosophila embryonic axis extension, actomyosin has a specific planar-polarised organisation, which is responsible for oriented cell intercalation. In addition to these cell rearrangements, cell shape changes also contribute to tissue deformation. While cell-autonomous dynamics are well described, understanding the tissue-scale behaviour challenges us to solve the corresponding mechanical problem at the scale of the whole embryo, since mechanical resistance of all neighbouring epithelia will feedback on individual cells. Here we propose a novel numerical approach to compute the whole-embryo dynamics of the actomyosin-rich apical epithelial surface. We input in the model specific patterns of actomyosin contractility, such as the planar-polarisation of actomyosin in defined ventro-lateral regions of the embryo. Tissue strain rates and displacements are then predicted over the whole embryo surface according to the global balance of stresses and the material behaviour of the epithelium. Epithelia are modelled using a rheological law that relates the rate of deformation to the local stresses and actomyosin anisotropic contractility. Predicted flow patterns are consistent with the cell flows observed when imaging Drosophila axis extension in toto, using light sheet microscopy. The agreement between model and experimental data indicates that the anisotropic contractility of planar-polarised actomyosin in the ventro-lateral germband tissue can directly cause the tissue-scale deformations of the whole embryo. The three-dimensional mechanical balance is dependent on the geometry of the embryo, whose curved surface is taken into account in the simulations. Importantly, we find that to reproduce experimental flows, the model requires the presence of the cephalic furrow, a fold located anteriorly of the extending tissues. The presence of

  20. Communication: Global flux surface hopping in Liouville space

    Science.gov (United States)

    Wang, Linjun; Sifain, Andrew E.; Prezhdo, Oleg V.

    2015-11-01

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.

  1. Lack of association between gastric cancer and hopQ alleles in Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Kazemi Elham

    2016-01-01

    Full Text Available Helicobacter pylori use a number of mechanisms to survive in the stomach lumen. The presence of these bacteria in the stomach can lead to gastritis and reduction in stomach acid production. Acute inflammation can directly damage to the peripheral cells that are responsible for the secretion of acid. The risk of developing gastric carcinoma is associated to heterogeneity of Helicobacter pylori virulence factors (such as cagA. The HopQ is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also play a role in the virulence of H. pylori. This gene has been shown in two types. The purpose of the current study was to investigate the association between different H. pylori virulence hopQ alleles (types I and II and patients with gastroduodenal disorders. For this purpose 58 stomach biopsies the of patients with gastric cancer and 100 saliva samples from healthy individuals were collected. Then genomic DNA was purified and PCR for was done for desired genes via specific primers. The H. pylori infections were diagnosed by PCR for GlmM gene. Then frequencies of hopQI+, hopQII+ and hopQI+ hopQII+ genotypes were determined in H. pylori infected cases. Statistical analysis showed that there were not significant differences between healthy and diseased ones for genotypes hopQI+, hopQII+ and hopQI+ hopQII+.

  2. Extreme Kinematics in Selected Hip Hop Dance Sequences.

    Science.gov (United States)

    Bronner, Shaw; Ojofeitimi, Sheyi; Woo, Helen

    2015-09-01

    Hip hop dance has many styles including breakdance (breaking), house, popping and locking, funk, streetdance, krumping, Memphis jookin', and voguing. These movements combine the complexity of dance choreography with the challenges of gymnastics and acrobatic movements. Despite high injury rates in hip hop dance, particularly in breakdance, to date there are no published biomechanical studies in this population. The purpose of this study was to compare representative hip hop steps found in breakdance (toprock and breaking) and house and provide descriptive statistics of the angular displacements that occurred in these sequences. Six expert female hip hop dancers performed three choreographed dance sequences, top rock, breaking, and house, to standardized music-based tempos. Hip, knee, and ankle kinematics were collected during sequences that were 18 to 30 sec long. Hip, knee, and ankle three-dimensional peak joint angles were compared in repeated measures ANOVAs with post hoc tests where appropriate (pHip hop maximal joint angles exceeded reported activities of daily living and high injury sports such as gymnastics. Hip hop dancers work at weight-bearing joint end ranges where muscles are at a functional disadvantage. These results may explain why lower extremity injury rates are high in this population.

  3. Characteristics of compounds in hops using cyclic voltammetry, UV-VIS, FTIR and GC-MS analysis.

    Science.gov (United States)

    Masek, Anna; Chrzescijanska, Ewa; Kosmalska, Anna; Zaborski, Marian

    2014-08-01

    The article presents the antioxidant properties of the extracts of hop EI and EII, by the electrochemical methods on a platinum electrode and comparative analysis of the composition of the extracts of hops using UV-VIS, FTIR and GC-MS methods. The hops extract EI, was obtained from the waste of the hops cone. The hops extract EII, was obtained from the hops cone itself. Hops contain a wide range of polyphenolic compounds with antioxidant properties divided in various chemical classes. Flavonoids and other polyphenolic compounds contained in hops show antioxidant capacity because of the presence of hydroxyl groups in various configurations and numbers within their molecules. The electrochemical properties and antioxidant capacity of hop samples were determined to select the most effective antioxidant. Based on the cyclic and pulse voltammograms, it was observed that hop extract EI contains polyphenols that are oxidised at a less positive potential than extract EII, i.e., it shows better antioxidant capacity. From the analysis of the UV-VIS and FTIR spectra and the GC-MS analysis, it was observed that extract EI contains less phenyl compounds than EII. In addition to flavonoids, EII contains hop acids and chlorophyll. The solutions of hop extracts show very good antioxidant capacities; therefore, they can effectively inhibit or slow negative oxidation reactions and scavenge free radicals and reactive oxygen species (ROS). Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Generalized adiabatic polaron hopping: Meyer-Neldel compensation and Poole-Frenkel behavior.

    Science.gov (United States)

    Emin, David

    2008-04-25

    The commonly employed adiabatic treatment of polaron hopping is extended to treat the continuous alteration of a carrier wave function with the atoms' movements and a carrier's long-range interaction with a polar surrounding. These features, respectively, introduce carrier-induced softening of the atoms' vibrations and a hopping activation energy that depends on hopping distance. The Meyer-Neldel compensation effect results from carrier-induced softening of vibrations. Poole-Frenkel behavior emerges for electric-field driven polaron hopping in ionic and polar media.

  5. Animal galloping and human hopping: an energetics and biomechanics laboratory exercise.

    Science.gov (United States)

    Lindstedt, Stan L; Mineo, Patrick M; Schaeffer, Paul J

    2013-12-01

    This laboratory exercise demonstrates fundamental principles of mammalian locomotion. It provides opportunities to interrogate aspects of locomotion from biomechanics to energetics to body size scaling. It has the added benefit of having results with robust signal to noise so that students will have success even if not "meticulous" in attention to detail. First, using respirometry, students measure the energetic cost of hopping at a "preferred" hop frequency. This is followed by hopping at an imposed frequency half of the preferred. By measuring the O2 uptake and work done with each hop, students calculate mechanical efficiency. Lessons learned from this laboratory include 1) that the metabolic cost per hop at half of the preferred frequency is nearly double the cost at the preferred frequency; 2) that when a person is forced to hop at half of their preferred frequency, the mechanical efficiency is nearly that predicted for muscle but is much higher at the preferred frequency; 3) that the preferred hop frequency is strongly body size dependent; and 4) that the hop frequency of a human is nearly identical to the galloping frequency predicted for a quadruped of our size. Together, these exercises demonstrate that humans store and recover elastic recoil potential energy when hopping but that energetic savings are highly frequency dependent. This stride frequency is dependent on body size such that frequency is likely chosen to maximize this function. Finally, by requiring students to make quantitative solutions using appropriate units and dimensions of the physical variables, these exercises sharpen analytic and quantitative skills.

  6. Influence of the constituent alpha acids of Ukrainian varieties of hops and hop preparations on quality indicators of mash and beer

    Directory of Open Access Journals (Sweden)

    L. Protsenko

    2015-05-01

    Full Text Available Introduction. The aim of the study is to establish the dependence of the bitterness of mash and the beer intoxication on the quality and quantity of the homologues of alpha acids in the Ukrainian varieties of hops, and on the content of cohumulone in alpha acids in particular. Materials and methods.Aromatic and bitter hop sorts of Ukrainian selection with different content of cohumulone in alpha-acids were investigated and so was the beer, made of these components. High performance liquid chromatography (HPLC was used to determine the amount and composition of bitter hop substances and their transformation products in the brewing process; also there were spectrophotometric methods for quality control of bitterness of hopped mash and finished beer in use. Results and discussion. The composition of bitter substances of aromatic and bitter hop sorts of Ukrainian selection was analyzed and so the beer, made of them. It was noted that the alpha-acids of the analyzed sorts incorporate a wide range of cohumulone content rated from 16.7% in the Kumyr sort to 44,1% in the Ruslan sort. The dependences between the quality and quantity of the bitter hop sorts and bitterness and quality of hopped mash and beer were established. The content of cohumulone in alphaacids of hops has to be less than 28% to obtain quality bitter beer. The role of the beta-acid compoundsin the formation of bitter mash, hopped with aroma hop varieties with a ratio of beta to alpha acids acids around one, is much more important compared to the bitter varieties. Conclusions. The conducted researches show that in applying the bitter hops with different compositon of alphaacids for mash intoxication, this usage is more effective in the sorts that have a large content of cohumulone.

  7. Security for multi-hop wireless networks

    CERN Document Server

    Mahmoud, Mohamed M E A

    2014-01-01

    This Springer Brief discusses efficient security protocols and schemes for multi-hop wireless networks. It presents an overview of security requirements for these networks, explores challenges in securing networks and presents system models. The authors introduce mechanisms to reduce the overhead and identify malicious nodes that drop packets intentionally. Also included is a new, efficient cooperation incentive scheme to stimulate the selfish nodes to relay information packets and enforce fairness. Many examples are provided, along with predictions for future directions of the field. Security

  8. Hopping in a Molecular Wire

    Directory of Open Access Journals (Sweden)

    R. Marco

    2004-12-01

    Full Text Available We utilize the Hubbard model approach in analyzing the effect of the hopping parameter in the transport properties of a two-atom molecular device (Kostyrko & Bulka, 2003. The system consists of a molecule with two identical atoms connecting two metal electrodes. In this model, two important and realistic energy parameters are considered which affects the transport properties. The first is the kinetic energy required to “hop” from one atomic site to the next. We call this parameter the hopping term denoted by t, in arbitrary units of energy. The next is an on-site Coulombic repulsion, U, between two electrons on the same atomic site.

  9. Hip-Hop and the Academic Canon

    Science.gov (United States)

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  10. Hip-Hop Pop Art

    Science.gov (United States)

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  11. Chicano Hip-Hop as Interethnic Contact Zone

    Science.gov (United States)

    McFarland, Pancho

    2008-01-01

    Hip-hop is an interethnic contact zone that allows for the creation of new expressive cultures and new identities for young people. Its openness derives in part from the wide range of expression and interpretation allowed in 182 "McFarland" African musics. Moving beyond the often stifling options offered by an earlier generation that focused on…

  12. Bilateral deficit of spring-like behaviour during hopping in sprinters.

    Science.gov (United States)

    Otsuka, Mitsuo; Kurihara, Toshiyuki; Isaka, Tadao

    2017-12-20

    Unilateral leg stiffness is a key contributor to sprint running speed, thereby great bilateral deficit (BLD) of leg stiffness would be expected to be observed in sprinters. However, it remains clear only BLD of leg stiffness at the preferred hopping frequency in non-sprinters. The purpose of this study was to clarify the BLD of spring-like behaviour in hopping at various frequencies and the effect of chronic adaptation via sprint running experience on BLD during the hopping. Fifteen male experienced sprinters and 12 male novices participated in this study. They were instructed to hop in place at three frequencies (2.0, 2.5, and 3.0 Hz), and to perform hopping with maximal effort. Ground reaction forces (GRF) of both legs during the hopping were recorded using two force plates. At higher hopping frequencies during the unilateral and bilateral hopping, smaller peak value of vertical GRF (F max) and greater leg stiffness (K leg) were significantly observed. The BLD index of F max and the BLD index of K leg were significantly smaller at higher hopping frequencies. No significant differences of BLD index of F max and BLD index of K leg were observed between sprinters and novices. Our results demonstrate that neuromuscular inhibition in the contralateral leg changes during the hopping based on hopping frequency. This suggests that plyometric training in the beginning of rehabilitation should involve bilateral jumping at a high frequency. In experienced sprinters, detailed mechanics of chronic neuromuscular adaptation via unilateral facilitation of spring-like behaviour should be assessed by measuring electromyographic activity.

  13. Basin Hopping Graph

    DEFF Research Database (Denmark)

    Kucharik, Marcel; Hofacker, Ivo; Stadler, Peter

    2014-01-01

    basins when the direct transitions between them are “energetically favorable”. Edge weights endcode the corresponding saddle heights and thus measure the difficulties of these favorable transitions. BHGs can be approximated accurately and efficiently for RNA molecules well beyond the length range...

  14. Hopping models and ac universality

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    2002-01-01

    Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA) is the h......Some general relations for hopping models are established. We proceed to discuss the universality of the ac conductivity which arises in the extreme disorder limit of the random barrier model. It is shown that the relevant dimension entering into the diffusion cluster approximation (DCA......) is the harmonic (fracton) dimension of the diffusion cluster. The temperature scaling of the dimensionless frequency entering into the DCA is discussed. Finally, some open problems regarding ac universality are listed....

  15. Three-Dimensional Tracking of Interfacial Hopping Diffusion

    Science.gov (United States)

    Wang, Dapeng; Wu, Haichao; Schwartz, Daniel K.

    2017-12-01

    Theoretical predictions have suggested that molecular motion at interfaces—which influences processes including heterogeneous catalysis, (bio)chemical sensing, lubrication and adhesion, and nanomaterial self-assembly—may be dominated by hypothetical "hops" through the adjacent liquid phase, where a diffusing molecule readsorbs after a given hop according to a probabilistic "sticking coefficient." Here, we use three-dimensional (3D) single-molecule tracking to explicitly visualize this process for human serum albumin at solid-liquid interfaces that exert varying electrostatic interactions on the biomacromolecule. Following desorption from the interface, a molecule experiences multiple unproductive surface encounters before readsorption. An average of approximately seven surface collisions is required for the repulsive surfaces, decreasing to approximately two and a half for surfaces that are more attractive. The hops themselves are also influenced by long-range interactions, with increased electrostatic repulsion causing hops of longer duration and distance. These findings explicitly demonstrate that interfacial diffusion is dominated by biased 3D Brownian motion involving bulk-surface coupling and that it can be controlled by influencing short- and long-range adsorbate-surface interactions.

  16. Proprioceptive Neuromuscular Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function.

    Science.gov (United States)

    Hindle, Kayla B; Whitcomb, Tyler J; Briggs, Wyatt O; Hong, Junggi

    2012-03-01

    Proprioceptive neuromuscular facilitation (PNF) is common practice for increasing range of motion, though little research has been done to evaluate theories behind it. The purpose of this study was to review possible mechanisms, proposed theories, and physiological changes that occur due to proprioceptive neuromuscular facilitation techniques. Four theoretical mechanisms were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory. The studies suggest that a combination of these four mechanisms enhance range of motion. When completed prior to exercise, proprioceptive neuromuscular facilitation decreases performance in maximal effort exercises. When this stretching technique is performed consistently and post exercise, it increases athletic performance, along with range of motion. Little investigation has been done regarding the theoretical mechanisms of proprioceptive neuromuscular facilitation, though four mechanisms were identified from the literature. As stated, the main goal of proprioceptive neuromuscular facilitation is to increase range of motion and performance. Studies found both of these to be true when completed under the correct conditions. These mechanisms were found to be plausible; however, further investigation needs to be conducted. All four mechanisms behind the stretching technique explain the reasoning behind the increase in range of motion, as well as in strength and athletic performance. Proprioceptive neuromuscular facilitation shows potential benefits if performed correctly and consistently.

  17. Comparative transcriptional analysis of hop responses to infection with Verticillium nonalfalfae.

    Science.gov (United States)

    Progar, Vasja; Jakše, Jernej; Štajner, Nataša; Radišek, Sebastjan; Javornik, Branka; Berne, Sabina

    2017-10-01

    Dynamic transcriptome profiling revealed excessive, yet ineffective, immune response to V. nonalfalfae infection in susceptible hop, global gene downregulation in shoots of resistant hop and only a few infection-associated genes in roots. Hop (Humulus lupulus L.) production is hampered by Verticillium wilt, a disease predominantly caused by the soil-borne fungus Verticillium nonalfalfae. Only a few hop cultivars exhibit resistance towards it and mechanisms of this resistance have not been discovered. In this study, we compared global transcriptional responses in roots and shoots of resistant and susceptible hop plants infected by a lethal strain of V. nonalfalfae. Time-series differential gene expression profiles between infected and mock inoculated plants were determined and subjected to network-based analysis of functional enrichment. In the resistant hop cultivar, a remarkably low number of genes were differentially expressed in roots in response to V. nonalfalfae infection, while the majority of differentially expressed genes were down-regulated in shoots. The most significantly affected genes were related to cutin biosynthesis, cell wall biogenesis, lateral root development and terpenoid biosynthesis. On the other hand, susceptible hop exhibited a strong defence response in shoots and roots, including increased expression of genes associated with plant responses, such as innate immunity, wounding, jasmonic acid pathway and chitinase activity. Strong induction of defence-associated genes in susceptible hop and a low number of infection-responsive genes in the roots of resistant hop are consistent with previous findings, confirming the pattern of excessive response of the susceptible cultivar, which ultimately fails to protect the plant from V. nonalfalfae. This research offers a multifaceted overview of transcriptional responses of susceptible and resistant hop cultivars to V. nonalfalfae infection and represents a valuable resource in the study of this plant

  18. Fundamentals of beer and hop chemistry

    OpenAIRE

    De Keukeleire, Denis

    2000-01-01

    Beer brewing is an intricate process encompassing mixing and further elaboration of four essential raw materials, including barley malt, brewing water, hops and yeast. Particularly hops determine to a great extent typical beer qualities such as bitter taste, hoppy flavour, and foam stability. Conversely, hop-derived bitter acids account for an offending lightstruck flavour, which is formed on exposure of beer to light. These various processes are presented in detail, while due emphasis is pla...

  19. Fundamentals of beer and hop chemistry

    Directory of Open Access Journals (Sweden)

    Denis De Keukeleire

    2000-02-01

    Full Text Available Beer brewing is an intricate process encompassing mixing and further elaboration of four essential raw materials, including barley malt, brewing water, hops and yeast. Particularly hops determine to a great extent typical beer qualities such as bitter taste, hoppy flavour, and foam stability. Conversely, hop-derived bitter acids account for an offending lightstruck flavour, which is formed on exposure of beer to light. These various processes are presented in detail, while due emphasis is placed on state-of-the-art hop technology, which provides brewers with efficient means to control bitterness, foam, and light-stability thereby allowing for the production of beers with consistent quality.

  20. Free energy basin-hopping

    Science.gov (United States)

    Sutherland-Cash, K. H.; Wales, D. J.; Chakrabarti, D.

    2015-04-01

    A global optimisation scheme is presented using basin-hopping with the acceptance criterion based on approximate free energy for the corresponding local minima of the potential energy. The method is illustrated for atomic and colloidal clusters and peptides to examine how the predicted global free energy minimum changes with temperature. Using estimates for the local free energies based on harmonic vibrational densities of states provides a computationally effective framework for predicting trends in structure at finite temperature. The resulting scheme represents a powerful tool for exploration of energy landscapes throughout molecular science.

  1. Fasilitas Pelatihan dan Pergelaran Seni Tari Hip Hop di Surabaya

    OpenAIRE

    Yanuar, Sandy

    2014-01-01

    Fasilitas Pelatihan dan Pergelaran Seni Tari Hip Hop di Surabaya merupakan fasilitas yang disediakan bagi semua penari Hip Hop di Surabaya untuk berlatih menari dan mempertunjukan tarian Hip Hop. Fasilitas ini tersedia bagi semua penari Hip Hop termasuk penari difable, mengingat kaum difable juga dapat menari Hip Hop. Namun karena di Surabaya belum memiliki fasilitas yang memadai bagi semua penari Hip Hop termasuk penari difable untuk menari dan memiliki tempat pertunjukan yang berkarakter Hi...

  2. Sclerotinia wilt of Hop (Humulus lupulus) caused by Sclerotinia sclerotiorum in the Pacific Northwest U.S.

    Science.gov (United States)

    Sclerotinia sclerotiorum is a widespread, destructive pathogen with an exceptionally broad host range. During June 2011, wilted hop plants (Humulus lupulus cv. Nugget) were observed in a hop yard in Marion County, Oregon. Some affected plants had upward curled leaves with necrotic margins, whereas o...

  3. Hops

    Science.gov (United States)

    ... by mouth for medicinal uses. Special precautions & warnings: Pregnancy and breast-feeding: There is not enough reliable ... that are changed by the liver include theophylline, omeprazole, clozapine, progesterone, lansoprazole, flutamide, oxaliplatin, erlotinib, and caffeine. ...

  4. Hop-by-HopWorm Propagation with Carryover Epidemic Model in Mobile Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jun-Won Ho

    2015-10-01

    Full Text Available In the internet, a worm is usually propagated in a random multi-hop contact manner. However, the attacker will not likely select this random multi-hop propagation approach in a mobile sensor network. This is because multi-hop worm route paths to random vulnerable targets can be often breached due to node mobility, leading to failure of fast worm spread under this strategy. Therefore, an appropriate propagation strategy is needed for mobile sensor worms. To meet this need, we discuss a hop-by-hop worm propagation model in mobile sensor networks. In a hop-by-hop worm propagation model, benign nodes are infected by worm in neighbor-to-neighbor spread manner. Since worm infection occurs in hop-by-hop contact, it is not substantially affected by a route breach incurred by node mobility. We also propose the carryover epidemic model to deal with the worm infection quota deficiency that might occur when employing an epidemic model in a mobile sensor network. We analyze worm infection capability under the carryover epidemic model. Moreover, we simulate hop-by-hop worm propagation with carryover epidemic model by using an ns-2 simulator. The simulation results demonstrate that infection quota carryovers are seldom observed where a node’s maximum speed is no less than 20 m/s.

  5. Pertunjukan Teater Karo Hip Hop Kontemporer KAI

    Directory of Open Access Journals (Sweden)

    Silvia Anggreni Purba

    2013-11-01

    Pertunjukan Teater Karo Hip Hop Kontemporer KAI. The performance of Karo Theater collaborated with Hip Hop stems from a simple idea to collaborate Karo cultural traditions with popular culture. The performances can be enjoyed without having limitation on the language and culture. The process of combining two different cultures is a form of hybrid culture, and it may occur due to the globalization process. Through the process of deposition of the observations and strong impression, this performance is then brought into the form of Hip Hop as a preferred form which is energetic, personal and global. This performance is part of a modern tragedy with its destructive character which has explored the emotion and has presented it to the audiences. The exploration of Karo cultural tradition and Hip Hop dance as a language of symbols is able to reinforce words. The movement is not revealed by the verbal phrase but is presented through the movement of Hip Hop dance. The interpretation of the legend and texts into movement is carried out through the training process at the laboratory as a searching process and experiment, and afterward can be realized by considering the basic elements of Hip Hop, Karo cultural elements and performance. Karo Hip Hop Theatre is expected to become a preferred aesthetic form of a modern theater without losing its tradition form. Keyword: a contemporary Karo theater, Hip Hop, hybrid culture.

  6. Biomechanical differences between incline and plane hopping.

    Science.gov (United States)

    Kannas, Theodoros M; Kellis, Eleftherios; Amiridis, Ioannis G

    2011-12-01

    Kannas, TM, Kellis, E, and Amiridis, IG. Biomechanical differences between incline and plane hopping. J Strength Cond Res 25(12): 3334-3341, 2011-The need for the generation of higher joint power output during performance of dynamic activities led us to investigate the force-length relationship of the plantar flexors during consecutive stretch-shortening cycles of hopping. The hypothesis of this study was that hopping (consecutive jumps with the knee as straight as possible) on an inclined (15°) surface might lead to a better jumping performance compared with hopping on a plane surface (0°). Twelve active men performed 3 sets of 10 consecutive hops on both an incline and plane surface. Ground reaction forces; ankle and knee joint kinematics; electromyographic (EMG) activity from the medial gastrocnemius (MG), soleus (Sol) and tibialis anterior (TA); and architectural data from the MG were recorded. The results showed that participants jumped significantly higher (p plane surface (27.52 ± 4.97 cm). No differences in temporal characteristics between the 2 types of jumps were observed. Incline hopping induced significantly greater ankle dorsiflexion and knee extension at takeoff compared with plane hopping (p propulsion phase were significantly higher during incline compared with that during plane hopping (p plane surface.

  7. How Does a Hopping Kangaroo Breathe?

    Science.gov (United States)

    Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

    2010-01-01

    We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

  8. Hip-hop and urban studies

    NARCIS (Netherlands)

    Jaffe, R.

    2014-01-01

    How can urban studies research engage fruitfully with hip-hop? This contribution responds to the essays by David Beer and Martin Lamotte on ‘street music’, urban ethnography and ghettoized communities. It discusses how a social science engagement with hip-hop texts might differ from cultural studies

  9. Protein sliding and hopping kinetics on DNA

    CERN Document Server

    DeSantis, Michael C; Wang, Y M

    2010-01-01

    Using Monte-Carlo simulations, we deconvolved the sliding and hopping kinetics of GFP-LacI proteins on elongated DNA from their experimentally observed seconds-long diffusion trajectories. Our simulations suggest the following results: (1) in each diffusion trajectory, a protein makes on average hundreds of alternating slides and hops with a mean sliding time of several tens of ms; (2) sliding dominates the root mean square displacement of fast diffusion trajectories, whereas hopping dominates slow ones; (3) flow and variations in salt concentration have limited effects on hopping kinetics, while in vivo DNA configuration is not expected to influence sliding kinetics; furthermore, (4) the rate of occurrence for hops longer than 200 nm agrees with experimental data for EcoRV proteins.

  10. Small polaron hopping transport along DNA molecules

    Energy Technology Data Exchange (ETDEWEB)

    Triberis, G P [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, GR-15784 Zografos, Athens (Greece); Simserides, C [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, GR-15784 Zografos, Athens (Greece); Leibniz Institute for Neurobiology, Special Laboratory for Non-Invasive Brain Imaging, Brenneckestrasse 6, D-39118 Magdeburg (Germany); Karavolas, V C [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, GR-15784 Zografos, Athens (Greece)

    2005-05-04

    We present a small polaron hopping model for interpreting the strong temperature (T) dependence of the electrical conductivity, {sigma}, observed at high (h) temperatures along DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. Percolation-theoretical considerations lead to analytical expressions for the high temperature multiphonon-assisted small polaron hopping conductivity, the hopping distance and their temperature dependence. The experimental data for lambda phage DNA ({lambda}-DNA) and poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behaviour (ln{sigma}{sup h}{proportional_to}T{sup -2/3}). Moreover, our model leads to realistic values of the maximum hopping distances, supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbours of the DNA molecular 'wire'. The low temperature case is also investigated.

  11. The Effect of Rap/Hip-Hop Music on Young Adult Smoking: An Experimental Study.

    Science.gov (United States)

    Harakeh, Zeena; Bogt, Tom F M Ter

    2018-02-16

    Music may influence young people's behavior through its lyrics. Substance use references occur more frequently in rap/hip-hop than in other music genres. The aim was to examine whether the exposure to rap/hip-hop lyrics referring to substance use affected cigarette smoking. An experiment with a 3-group between subject design was conducted among 74 daily-smoking young adults ranging in age from 17 to 25 years old. Three conditions were tested in a mobile lab (camper vehicle) from May to December 2011, i.e., regular chart pop music (N = 28), rap/hip-hop with non-frequent references to substance use (N = 24), and rap/hip-hop with frequent references to substance use (N = 22). One-way ANOVA showed that participants listening to substance use infused rap/hip-hop songs felt significantly less pleasant, liked the songs less, and comprehended the songs less compared to participants listening to pop songs. Poisson loglinear analyses revealed that compared to the pop music condition, none of the two rap/hip-hop music conditions had a significant effect on acute smoking. Thus, contrary to expectations, the two different rap/hip-hop conditions did not have a significantly different effect on acute smoking. Listening to rap/hip-hop, even rap hip/hop with frequent referrals to substance use (primarily alcohol and drug use, and general smoking referrals), does not seem to encourage cigarette smoking among Dutch daily-smoking young adults, at least short term.

  12. Simulation of Frequency Hopping Communication System Based On MATLAB

    OpenAIRE

    Xu Xiaoping; Wang Weiqi; Yi Lan; Rong Jie; Wang Anqi

    2016-01-01

    In today’s information age, how to carry out the accurate information communication is a crucial issue in the field of communication, which is widely used in civil and military fields. Frequency hopping communication system is a typical spectrum communication system, it is in military communication, mobile communication, computer wireless data transmission and wireless LAN and other fields have a very wide range of applications, has become the current short wave communication is one of the im...

  13. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review.

    Science.gov (United States)

    Trenchard, Hugh; Perc, Matjaž

    2016-09-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems that include bacteria, spermatozoa, various aquatic species, birds, land animals, semi-fluid dwellers like turtle hatchlings, as well as human systems. We present the thermodynamic framework for energy saving mechanisms, and we review evidence in favor of the variation range hypothesis. This hypothesis posits that, as an evolutionary process, the variation range between strongest and weakest group members converges on the equivalent energy saving quantity that is generated by the energy saving mechanism. We also review self-organized structures that emerge due to energy saving mechanisms, including convective processes that can be observed in many systems over both short and long time scales, as well as high collective output processes in which a form of collective position locking occurs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Perceived bitterness character of beer in relation to hop variety and the impact of hop aroma.

    Science.gov (United States)

    Oladokun, Olayide; James, Sue; Cowley, Trevor; Dehrmann, Frieda; Smart, Katherine; Hort, Joanne; Cook, David

    2017-09-01

    The impact of hop variety and hop aroma on perceived beer bitterness intensity and character was investigated using analytical and sensory methods. Beers made from malt extract were hopped with 3 distinctive hop varieties (Hersbrucker, East Kent Goldings, Zeus) to achieve equi-bitter levels. A trained sensory panel determined the bitterness character profile of each singly-hopped beer using a novel lexicon. Results showed different bitterness character profiles for each beer, with hop aroma also found to change the hop variety-derived bitterness character profiles of the beer. Rank-rating evaluations further showed the significant effect of hop aroma on selected key bitterness character attributes, by increasing perceived harsh and lingering bitterness, astringency, and bitterness intensity via cross-modal flavour interactions. This study advances understanding of the complexity of beer bitterness perception by demonstrating that hop variety selection and hop aroma both impact significantly on the perceived intensity and character of this key sensory attribute. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Mixed quantum-classical equilibrium: Surface hopping.

    Science.gov (United States)

    Schmidt, J R; Parandekar, Priya V; Tully, John C

    2008-07-28

    We re-examine the analysis of the equilibrium limits of the fewest switches surface hopping algorithm for mixed quantum-classical dynamics. In contrast with previously reported results, we show that surface hopping does not, in general, exactly yield Boltzmann equilibrium, but that in practice the observed deviations are quite small. We also demonstrate that surface hopping does approach the exact equilibrium distribution in both the limits of small adiabatic splitting and/or strong nonadiabatic coupling. We verify these analytical results with numerical simulations for a simple two-level quantum system connected to a bath of classical particles.

  16. Stationary Currents in Particle Systems with Constrained Hopping Rates

    Science.gov (United States)

    Cirillo, Emilio N. M.; Colangeli, Matteo; Muntean, Adrian

    2016-04-01

    We study the effect on the stationary currents of constraints affecting the hopping rates in stochastic particle systems. In the framework of zero range processes with drift within a finite volume, we discuss how the current is reduced by the presence of the constraint and deduce exact formulae, fully explicit in some cases. The model discussed here has been introduced by Cirillo et al. (Does communication enhance pedestrians transport in the dark? To appear in C. R. Mécanique 344 (2016), 19-23) and is relevant for the description of pedestrian motion in elongated dark corridors, where the constraint on the hopping rates can be related to limitations on the interaction distance among pedestrians, but finds also applications in the modeling of various transport phenomena.

  17. Statistical mechanics in biology: how ubiquitous are long-range correlations?

    Science.gov (United States)

    Stanley, H. E.; Buldyrev, S. V.; Goldberger, A. L.; Goldberger, Z. D.; Havlin, S.; Mantegna, R. N.; Ossadnik, S. M.; Peng, C.-K.; Simons, M.

    1994-04-01

    The purpose of this opening talk is to describe examples of recent progress in applying statistical mechanics to biological systems. We first briefly review several biological systems, and then focus on the fractal features characterized by the long-range correlations found recently in DNA sequences containing non-coding material. We discuss the evidence supporting the finding that for sequences containing only coding regions, there are no long-range correlations. We also discuss the recent finding that the exponent α characterizing the long-range correlations increases with evolution, and we discuss two related models, the insertion model and the insertion-deletion model, that may account for the presence of long-range correlations. Finally, we summarize the analysis of long-term data on human heartbeats (up to 10 4 heart beats) that supports the possibility that the successive increments in the cardiac beat-to-beat intervals of healthy subjects display scale-invariant, long-range “anti-correlations” (a tendency to beat faster is balanced by a tendency to beat slower later on). In contrast, for a group of subjects with severe heart disease, long-range correlations vanish. This finding suggests that the classical theory of homeostasis, according to which stable physiological processes seek to maintain “constancy,” should be extended to account for this type of dynamical, far from equilibrium, behavior.

  18. Hip-hop, Onegin - pop! / Tatjana Aleksandrova

    Index Scriptorium Estoniae

    Aleksandrova, Tatjana, 1945-

    2004-01-01

    Erateatrikooli KS, mida juhib Svetlana Krassman, lavastus A. Pushkini poeemi "Jevgeni Onegin" motiividel. Noortelavastuse muusikalises seades kasutatakse klassikalise muusika aranzheeringuid ja räppi, kostüümidraamat koos hip-hop rõivastiiliga

  19. Random free energy barrier hopping model for ac conduction in chalcogenide glasses

    Directory of Open Access Journals (Sweden)

    Ram Murti

    2016-03-01

    Full Text Available The random free energy barrier hopping model is proposed to explain the ac conductivity (σac of chalcogenide glasses. The Coulomb correlation is consistently accounted for in the polarizability and defect distribution functions and the relaxation time is augmented to include the overlapping of hopping particle wave functions. It is observed that ac and dc conduction in chalcogenides are due to same mechanism and Meyer-Neldel (MN rule is the consequence of temperature dependence of hopping barriers. The exponential parameter s is calculated and it is found that s is subjected to sample preparation and measurement conditions and its value can be less than or greater than one. The calculated results for a − Se, As2S3, As2Se3 and As2Te3 are found in close agreement with the experimental data. The bipolaron and single polaron hopping contributions dominates at lower and higher temperatures respectively and in addition to high energy optical phonons, low energy optical and high energy acoustic phonons also contribute to the hopping process. The variations of hopping distance with temperature is also studied. The estimated defect number density and static barrier heights are compared with other existing calculations.

  20. Effect of high aluminum consumption on mechanics and composition of furculae of free-ranging coots

    Science.gov (United States)

    Hui, C.A.; Ellers, O.

    1999-01-01

    High levels of ingested Al can affect mechanical properties of bones. Because of the spring action of the furcula during the wingbeat, small changes in the mechanical properties of this bone may have measurable impacts on long-distance flight. We examined the furculae and ingesta of free- ranging American coots (Fulica americana) in San Francisco Bay (California, USA), where they consume a diet high in Al. We measured the spring stiffness and phase angle (??) of the furculae and the concentrations of Al, Ca, F. Mg, and P in both the furculae and ingesta. The ingesta had mean Al concentrations (2,384 ??g/g, dry weight) and Al:P molar ratios (6.4:1) predicted to affect bone integrity but the bone concentrations of Al were near the normal range and the furcula stiffness did not change with Al concentration. The tan ?? of the furculae changed with Al concentration but the relationship was weak. The chemical speciation of the ingested Al may have affected its physiologic role and the high mean levels of ingested calcium (71,283 ??g/g, dry weight) very likely neutralized the activity of the Al. Controlled feeding studies have shown that F strengthens avian bones. The bones in our study had molar concentrations of F more than two orders of magnitude greater than Al (170:1) but F appears to have insignificant influence on bone mechanics. The coots in San Francisco Bay apparently are not suffering furcula impairment despite a diet high in Al.

  1. Fast Hopping Frequency Generation in Digital CMOS

    CERN Document Server

    Farazian, Mohammad; Gudem, Prasad S

    2013-01-01

    Overcoming the agility limitations of conventional frequency synthesizers in multi-band OFDM ultra wideband is a key research goal in digital technology. This volume outlines a frequency plan that can generate all the required frequencies from a single fixed frequency, able to implement center frequencies with no more than two levels of SSB mixing. It recognizes the need for future synthesizers to bypass on-chip inductors and operate at low voltages to enable the increased integration and efficiency of networked appliances. The author examines in depth the architecture of the dividers that generate the necessary frequencies from a single base frequency and are capable of establishing a fractional division ratio.   Presenting the first CMOS inductorless single PLL 14-band frequency synthesizer for MB-OFDMUWB makes this volume a key addition to the literature, and with the synthesizer capable of arbitrary band-hopping in less than two nanoseconds, it operates well within the desired range on a 1.2-volt power s...

  2. HIP HOP for HIV Awareness: Using Hip Hop Culture to Promote Community-Level HIV Prevention

    Science.gov (United States)

    Hill, Mandy J.; Hallmark, Camden J.; McNeese, Marlene; Blue, Nike; Ross, Michael W.

    2014-01-01

    The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex…

  3. Resonant hopping of a robot controlled by an artificial neural oscillator.

    Science.gov (United States)

    Pelc, Evan H; Daley, Monica A; Ferris, Daniel P

    2008-06-01

    The bouncing gaits of terrestrial animals (hopping, running, trotting) can be modeled as a hybrid dynamic system, with spring-mass dynamics during stance and ballistic motion during the aerial phase. We used a simple hopping robot controlled by an artificial neural oscillator to test the ability of the neural oscillator to adaptively drive this hybrid dynamic system. The robot had a single joint, actuated by an artificial pneumatic muscle in series with a tendon spring. We examined how the oscillator-robot system responded to variation in two neural control parameters: descending neural drive and neuromuscular gain. We also tested the ability of the oscillator-robot system to adapt to variations in mechanical properties by changing the series and parallel spring stiffnesses. Across a 100-fold variation in both supraspinal gain and muscle gain, hopping frequency changed by less than 10%. The neural oscillator consistently drove the system at the resonant half-period for the stance phase, and adapted to a new resonant half-period when the muscle series and parallel stiffnesses were altered. Passive cycling of elastic energy in the tendon accounted for 70-79% of the mechanical work done during each hop cycle. Our results demonstrate that hopping dynamics were largely determined by the intrinsic properties of the mechanical system, not the specific choice of neural oscillator parameters. The findings provide the first evidence that an artificial neural oscillator will drive a hybrid dynamic system at partial resonance.

  4. Solid-phase microextraction of hop volatiles. Potential use for determination and verification of hop varieties.

    Science.gov (United States)

    Kovacevic, M; Kac, M

    2001-05-18

    The composition of hop essential oil is an important tool for evaluation of hop quality. As each hop variety has a typical essential oil pattern (fingerprint), hop oil analyses can be used to distinguish between hop varieties. The headspace solid-phase microextraction (SPME) method as described in this contribution is a simple sample preparation technique and represents an alternative procedure for essential oil fingerprint determination. Different SPME parameters (extraction temperature, extraction time and sample mass) were studied and the results were compared with those obtained by the routine distillation method. It is shown that SPME results can be used for determination and verification of varieties grown in Slovenia by means of principal components analysis.

  5. RAZVOJ OBLAČIL V HIP HOP KULTURI

    OpenAIRE

    Marić, Sanja

    2010-01-01

    V diplomskem delu smo raziskovali, kako so se hip hop oblačila razvijala skozi obdobja v hip hop kulturi. V teoretičnem deli smo ugotavljali ozadje in dejavnike, ki so vplivali na razvoj hip hop kulture, v empiričnem delu diplomske naloge pa smo izvedli anketni vprašalnik z glavnimi akterji hip hop kulture na slovenski hip hop sceni. Rezultati, ki smo jih dobili, kažejo da so imela oblačila velik vpliv na prepoznavnost in razvoj hip hop kulture po celem svetu. K temu so največ pripomogli ustv...

  6. Protein structure prediction using basin-hopping

    Science.gov (United States)

    Prentiss, Michael C.; Wales, David J.; Wolynes, Peter G.

    2008-06-01

    Associative memory Hamiltonian structure prediction potentials are not overly rugged, thereby suggesting their landscapes are like those of actual proteins. In the present contribution we show how basin-hopping global optimization can identify low-lying minima for the corresponding mildly frustrated energy landscapes. For small systems the basin-hopping algorithm succeeds in locating both lower minima and conformations closer to the experimental structure than does molecular dynamics with simulated annealing. For large systems the efficiency of basin-hopping decreases for our initial implementation, where the steps consist of random perturbations to the Cartesian coordinates. We implemented umbrella sampling using basin-hopping to further confirm when the global minima are reached. We have also improved the energy surface by employing bioinformatic techniques for reducing the roughness or variance of the energy surface. Finally, the basin-hopping calculations have guided improvements in the excluded volume of the Hamiltonian, producing better structures. These results suggest a novel and transferable optimization scheme for future energy function development.

  7. Procesos hopping a través del modelo difusional en materiales nanocristalinos usados para aplicaciones fotovoltaicas

    OpenAIRE

    Mesa, Fredy

    2014-01-01

    Se presentan los modelos de hopping de rango variable (variable range hopping; VRH), vecinos cercanos (nearest neighbor hopping; NNH) y barreras de potencial presentes en las fronteras de grano; como mecanismos de transporte eléctrico predominantes en los materiales semiconductores para aplicaciones fotovoltaicas. Las medidas de conductividad a oscuras en función de temperatura fueron realizadas para región de bajas temperaturas entre 120 y 400 K con Si y compuestos Cu3BiS2 y Cu2ZnSnSe4. Sigu...

  8. Agrochemical lead optimization by scaffold hopping.

    Science.gov (United States)

    Lamberth, Clemens

    2018-02-01

    Scaffold hopping, the exchange of a specific portion of a potential active ingredient with another substructure with the aim of finding isofunctional molecular structures with significantly different molecular backbones, often offers the chance in lead discovery or optimization to mitigate problems related to toxicity, intellectual property, and insufficient potency or stability. Scaffold hopping tools such as isosteric ring replacement including 1,3 nitrogen shift and cyclic imine-amide isosterism, but also ring opening and ring closure approaches, functional group isosterism, reversion of functional groups, chain shortening, chain lengthening, and scaffolds delivered by natural products, have become a permanent fixture of the innovation and optimization process in crop protection research. Their appropriate use will be explained through examples of success stories in the field of agrochemistry. Analogies to, but also differences from, the main categories of scaffold hopping in medicinal drug discovery are discussed. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Conscious Hip-Hop, Change, and the Obama Era

    Directory of Open Access Journals (Sweden)

    Murray Forman

    2010-05-01

    Full Text Available This article identifies a particular aspect of hip-hop’s range of cultural production—conscious rap—in order to isolate one of the more politicized discursive options available to youth in America and a site where critical perspectives on post-Civil Rights America have emerged most forcefully. It further suggests that Obama’s political rise corresponds with a new phase in hip-hop and has impacted the ways in which its creative artists frame and articulate issues of race, class, and identity.

  10. Between-session reliability of four hop tests and the agility T-test.

    Science.gov (United States)

    Munro, Allan G; Herrington, Lee C

    2011-05-01

    The purposes of this study were firstly to investigate whether learning affects were present in the administration of 4 hop tests and the Agility T-test and secondly to assess the between-session reliability of these tests. Twenty-two recreational athletes (11 women: age 22.3 ± 3.7 years, height 167.7 ± 6.2 cm, weight 59.2 ± 6.9 kg and 11 men: age 22.8 ± 3.1 years, height 179.8 ± 4 cm, weight 79.6 ± 10 kg) took part in the study. The subjects performed 6 repetitions of each hop test and 4 repetitions of the Agility T-test once a week over a period of 3 weeks. Distances were normalized to leg length and presented as a percentage value for the single, triple and crossover hop. Results showed that there were significant differences in scores between genders and that learning affects were present in all tests. Intraclass correlation coefficients ranged from 0.76 to 0.92 for the hop tests and 0.82 to 0.96 for the Agility T-test. The results indicated that the hop and Agility T-tests are reliable tests for use with subjects in a clinical or team sport environment. The error measurement statistics presented could be of help to practitioners to determine whether changes in individuals' scores in the hop and Agility T-tests are because of a true change in performance or measurement error. Of most importance was the fact that all subjects achieved at least 90% limb symmetry index on all 4 hop tests. Therefore, we recommend that a minimum limb symmetry value of 90%, rather than previously recommended 85%, should be adopted during rehabilitation and conditioning.

  11. Determinants of Job Hopping Experience among Private and Public ...

    African Journals Online (AJOL)

    The results revealed that perceive organizational justice; job stress and job hopping significantly jointly predict employees' turnover intention. Additionally, job stress, job hopping and distributive justice which is one of the dimensions of organizational independently significantly predict employees' turnover intention.

  12. Revolutionizing Environmental Education through Indigenous Hip Hop Culture

    Science.gov (United States)

    Gorlewski, Julie; Porfilio, Brad J.

    2012-01-01

    Based upon the life histories of six Indigenous hip hop artists of the Beat Nation artist collective, this essay captures how Indigenous hip hop has the potential to revolutionize environmental education. Hip hop provides Indigenous youth an emancipatory space to raise their opposition to neocolonial controls of Indigenous territories that…

  13. Bounds on the hop domination number of a tree

    Indian Academy of Sciences (India)

    A hop dominating set of a graph is a set of vertices of if for every vertex of () \\ D, there exists u ∈ D such that (, ) = 2. The hop domination number of a graph , denoted by ℎ(), is the minimum cardinality of a hop dominating set of . We prove that for every tree of order with leaves and support ...

  14. Hip-Hopping across China: Intercultural Formulations of Local Identities

    Science.gov (United States)

    Barrett, Catrice

    2012-01-01

    The linguistic dimensions of globalized hip-hop cannot be understood simply as a byproduct of English as an American export. As hip-hop mobilizes, it is common (and arguably necessary) for global hip-hop communities to struggle through purposeful, semiotically rooted dialectics over what constitutes "authentic" and respectable forms of…

  15. HPLC Analysis of [Alpha]- and [Beta]-Acids in Hops

    Science.gov (United States)

    Danenhower, Travis M.; Force, Leyna J.; Petersen, Kenneth J.; Betts, Thomas A.; Baker, Gary A.

    2008-01-01

    Hops have been used for centuries to impart aroma and bitterness to beer. The cones of the female hop plant contain both essential oils, which include many of the fragrant components of hops, and a collection of compounds known as [alpha]- and [beta]-acids that are the precursors to bittering agents. In order for brewers to predict the ultimate…

  16. 21 CFR 172.560 - Modified hop extract.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Modified hop extract. 172.560 Section 172.560 Food... Flavoring Agents and Related Substances § 172.560 Modified hop extract. The food additive modified hop extract may be safely used in beer in accordance with the following prescribed conditions: (a) The food...

  17. HopW1 from Pseudomonas syringae disrupts the actin cytoskeleton to promote virulence in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Yongsung Kang

    2014-06-01

    Full Text Available A central mechanism of virulence of extracellular bacterial pathogens is the injection into host cells of effector proteins that modify host cellular functions. HopW1 is an effector injected by the type III secretion system that increases the growth of the plant pathogen Pseudomonas syringae on the Columbia accession of Arabidopsis. When delivered by P. syringae into plant cells, HopW1 causes a reduction in the filamentous actin (F-actin network and the inhibition of endocytosis, a known actin-dependent process. When directly produced in plants, HopW1 forms complexes with actin, disrupts the actin cytoskeleton and inhibits endocytosis as well as the trafficking of certain proteins to vacuoles. The C-terminal region of HopW1 can reduce the length of actin filaments and therefore solubilize F-actin in vitro. Thus, HopW1 acts by disrupting the actin cytoskeleton and the cell biological processes that depend on actin, which in turn are needed for restricting P. syringae growth in Arabidopsis.

  18. Exact Open Quantum System Dynamics Using the Hierarchy of Pure States (HOPS).

    Science.gov (United States)

    Hartmann, Richard; Strunz, Walter T

    2017-11-09

    We show that the general and numerically exact Hierarchy of Pure States method (HOPS) is very well applicable to calculate the reduced dynamics of an open quantum system. In particular, we focus on environments with a sub-Ohmic spectral density (SD) resulting in an algebraic decay of the bath correlation function (BCF). The universal applicability of HOPS, reaching from weak to strong coupling for zero and nonzero temperature, is demonstrated by solving the spin-boson model for which we find perfect agreement with other methods, each one suitable for a special regime of parameters. The challenges arising in the strong coupling regime are not only reflected in the computational effort needed for the HOPS method to converge but also in the necessity for an importance sampling mechanism, accounted for by the nonlinear variant of HOPS. In order to include nonzero-temperature effects in the strong coupling regime we found that it is highly favorable for the HOPS method to use the zero-temperature BCF and include temperature via a stochastic Hermitian contribution to the system Hamiltonian.

  19. Odor-Active Compounds in the Special Flavor Hops Huell Melon and Polaris.

    Science.gov (United States)

    Neiens, Silva D; Steinhaus, Martin

    2018-02-05

    The volatiles isolated from samples of the special flavor hop varieties, Huell Melon and Polaris, and from the aroma hop variety, Hallertau Tradition, by solvent extraction and solvent-assisted flavor evaporation (SAFE) were subjected to a comparative aroma extract dilution analysis (cAEDA), which resulted in 46 odor-active compounds in the flavor dilution (FD) factor range of 16 to 2048. On the basis of high FD factors, myrcene, (3R)-linalool, and 2- and 3-methylbutanoic acid were confirmed as important variety-independent hop odorants. (1R,4S)-Calamenene was identified for the first time as an odor-active compound in hops. Clear differences in the FD factors and their subsequent objectification by stable isotope dilution quantitation suggested that high concentrations of the esters ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, and propyl 2-methylbutanoate cause the characteristic fruity, cantaloupe-like odor note in Huell Melon hops, whereas the fruity and minty odor notes in Polaris are associated with high amounts of 3-methylbutyl acetate and 1,8-cineole.

  20. Dripping or delamination? A range of mechanisms for removing the lower crust or lithosphere

    Science.gov (United States)

    Beall, Adam P.; Moresi, Louis; Stern, Tim

    2017-08-01

    Under some conditions, dense parts of the lower crust or mantle lithosphere can become unstable, deform internally and sink into the less dense, underlying asthenosphere. Two end-member mechanisms for this process are delamination and dripping. Numerical calculations are used to compare the time taken for each instability to grow from initiation to the point of rapid descent through the asthenosphere. This growth period is an order of magnitude shorter for delamination than dripping. For delamination, the growth rate varies proportionally to the buoyancy and viscosity of the sinking material, as with dripping. It also depends on the relative thickness (L^' }_c) and viscosity (η ^' }_c) of the weak layer which decouples the sinking material from the upper crust, varying proportionally to L_c^' 2}/η ^' 2/3}_c. As instabilities commonly resemble a mix of dripping and delamination, the analysis of initial instability growth includes a range of mechanisms in-between. Dripping which begins with a large perturbation and low η ^' }_c reproduces many of the characteristic features of delamination, yet its growth timescale is still an order of magnitude slower. Previous diagnostic features of delamination may therefore be ambiguous and if rheology is to be inferred from observed timescales, it is important that delamination and this 'triggered dripping' are distinguished. Transitions from one mechanism or morphology to another, during the initial growth stage, are also examined. 3-D models demonstrate that when η ^' }_c is small, a dripping, planar sheet will only transition into 3-D drips if the initial triggering perturbation is less than a third of the dense material's thickness. This transition occurs more easily at large η ^' }_c, so rheological heterogeneity may be responsible for morphological transitions through time. We also calculate the rates at which delamination grows too slowly to outpace cooling of the upwelling asthenosphere, resulting in stalling and

  1. The Philippine "Hip Hop Stick Dance"

    Science.gov (United States)

    Lewis, Lisa

    2012-01-01

    This article introduces a dance that blends the traditional cultural heritage of the Philippines with modern music and moves. "Hip Hop Stick Dance" incorporates Tinikling (the Philippine national dance) and Arnis (a Filipino style of martial arts) to create a contemporary combination of rhythm, dance, and fitness. It was designed to introduce…

  2. Uudised : Ooper. Hip-hop. Madonna

    Index Scriptorium Estoniae

    2005-01-01

    Rumeenia sopran Nelly Miricioiu Vincenzo Bellini ooperi "Norma" nimiosas Nederlandse Operas Amsaterdamis 7.-28. märtsini. 4. märtsil Tallinna klubis Hollywood üritusel "Hip-Hop Café" New Yorgi duo Camp Lo. Ameerika poplaulja Madonna võttis vastu filmirolli

  3. Injury incidence in hip hop dance.

    Science.gov (United States)

    Ojofeitimi, S; Bronner, S; Woo, H

    2012-06-01

    Hip hop dance has rapidly become a popular international art form. There is limited information on injury patterns in this population. The purpose of this study was to determine injury incidence and patterns among three groups of hip hop dancers. Three hundred and twelve intermediate, advanced, and expert hip hop dancers were recruited at battles, dance conferences, clubs, and on dance related web sites within the United States and internationally. A Web-based survey was conducted over a 6-month period. Inclusion criteria included intermediate and advanced level dancers over the age of 13. Dancers were divided into three main categories: Breakers, Popper/Lockers, and New Schoolers. Separate analysis of variances were used to compare injury pattern differences between groups. Two hundred and thirty-two dancers reported a total of 738 injuries. Five hundred and six of these (sustained by 205 dancers) were time-loss (TL) injuries. Annual injury incidence was 237% (162% involving TL). Lower extremity injuries were 52% and upper extremity injuries 32% of total injuries. Breakers had a higher injury incidence compared with Popper/Lockers, and New Schoolers. Hip hop dancers report injury rates that are higher than other dance forms but similar to gymnastics. These dancers should be educated concerning injury prevention, biomechanics, and use of protective equipment. © 2010 John Wiley & Sons A/S.

  4. Bridge Hopping on Conducting Polymers in Solution

    OpenAIRE

    Hone, Daniel W.; Orland, Henri

    2000-01-01

    Configurational fluctuations of conducting polymers in solution can bring into proximity monomers which are distant from each other along the backbone. Electrons can hop between these monomers across the "bridges" so formed. We show how this can lead to (i) a collapse transition for metallic polymers, and (ii) to the observed dramatic efficiency of acceptor molecules for quenching fluorescence in semiconducting polymers.

  5. The interplay of crack hopping, delamination and interface failure in drying nanoparticle films.

    Science.gov (United States)

    Yang, Bin; Sharp, James S; Smith, Mike I

    2016-08-25

    Films formed through the drying of nanoparticle suspensions release the build-up of strain through a variety of different mechanisms including shear banding, crack formation and delamination. Here we show that important connections exist between these different phenomena: delamination depends on the dynamics of crack hopping, which in turn is influenced by the presence of shear bands. We also show that delamination does not occur uniformly across the film. As cracks hop they locally initiate the delamination of the film which warps with a timescale much longer than that associated with the hopping of cracks. The motion of a small region of the delamination front, where the shear component of interfacial crack propagation is believed to be enhanced, results in the deposition of a complex zig-zag pattern on the supporting substrate.

  6. Featherless Dinosaurs and the Hip-Hop Simulacrum: Reconsidering Hip-Hop's Appropriateness for the Music Classroom

    Science.gov (United States)

    Kruse, Adam J.

    2016-01-01

    This article offers considerations for music teachers interested in including hip-hop music in their classrooms but who might feel concerned with or overwhelmed by issues of appropriateness. Two concerns related to hip-hop music are examined: language and negative social themes. Commercial interests in hip-hop music have created a simulacrum (or…

  7. The crossover between tunnel and hopping conductivity in granulated films of noble metals

    Science.gov (United States)

    Kavokin, Alexey; Kutrovskaya, Stella; Kucherik, Alexey; Osipov, Anton; Vartanyan, Tigran; Arakelyan, Sergey

    2017-11-01

    The conductivity of thin films composed by clusters of gold and silver nanoparticles has been studies in a wide range of temperatures. The switch from a temperature independence to an exponential thermal dependence of the conductivity manifests the crossover between the tunnel and thermally activated hopping regimes of the electronic transport at the temperature of 60 °C. The characteristic thermal activation energy that governs hopping of electrons between nanoparticles is estimated as 1.3 eV. We have achieved a good control of the composition and thicknesses of nano-cluster films by use of the laser ablation method in colloidal solutions.

  8. Stretch reflex improves rolling stability during hopping of a decerebrate biped system.

    Science.gov (United States)

    Rosendo, Andre; Liu, Xiangxiao; Shimizu, Masahiro; Hosoda, Koh

    2015-01-19

    When humans hop, attitude recovery can be observed in both the sagittal and frontal planes. While it is agreed that the brain plays an important role in leg placement, the role of low-level feedback (the stretch reflex) on frontal plane stabilization remains unclear. Seeking to better understand the contribution of the soleus stretch reflex to rolling stability, we performed experiments on a biomimetic humanoid hopping robot. Various reflex responses to touching the floor, ranging from no response to long muscle activations, were examined, and the effect of a delay upon touching the floor was also examined. We found that the stretch reflex brought the system closer to stable, straight hopping. The presence of a delay did not affect the results; both the cases with and without a delay outperformed the case without a reflex response. The results of this study highlight the importance of low-level control in locomotion for which body stabilization does not require higher-level signals.

  9. Tietoista liikettä : Hip hop -kulttuurin merkitys katutanssin opettamisessa

    OpenAIRE

    Pikkarainen, Sara

    2015-01-01

    Tutkimuksen lähtökohtana oli saada lisää tietoa siitä, kuinka keskeiseksi hip hop -kulttuurin ym-märtäminen koetaan osana tanssinopettajan ammattitaitoa. Tutkimuskysymykseni ovat: Miksi hip hop -kulttuurin ymmärtäminen on merkityksellistä tanssinopetuksen näkökulmasta? Miten hip hop -kulttuuri ilmenee katutanssinopetuksessa tanssikouluympäristössä? Jotta tutkimuskysymyksiin voidaan vastata, täytyy ymmärtää miten hip hop -kulttuuri on vaikuttanut hip hop -tanssin kehittymiseen ja miten hip...

  10. An amino acid substitution in the Drosophila hopTum-l Jak kinase causes leukemia-like hematopoietic defects.

    Science.gov (United States)

    Luo, H; Hanratty, W P; Dearolf, C R

    1995-01-01

    Proteins of the Jak family of non-receptor kinases play important roles in mammalian hematopoietic signal transduction. They mediate the cellular response to a wide range of cytokines and growth factors. A dominant mutation in a Drosophila Jak kinase, hopscotchTumorous-lethal (hopTum-l), causes hematopoietic defects. Here we conduct a molecular analysis of hopTum-l. We demonstrate that the hopTum-l hematopoietic phenotype is caused by a single amino acid substitution of glycine to glutamic acid at residue 341. We generate a true revertant of the hopTum-l mutation, in which both the molecular lesion and the mutant hematopoietic phenotype revert back to wild type. We also examine the effects of the G341E substitution in transgenic flies. The results indicate that a mutant Jak kinase can cause leukemia-like abnormalities. Images PMID:7729418

  11. Global Ill-Literacies: Hip Hop Cultures, Youth Identities, and the Politics of Literacy

    Science.gov (United States)

    Alim, H. Samy

    2011-01-01

    This article focuses on the emergence of what the author refers to as "global ill-literacies," that is, the hybrid, transcultural linguistic and literacy practices of Hip Hop youth in local and global contexts, as well as the pedagogical possibilities that scholars open up as they engage these forms. By reviewing a broad but focused range of…

  12. On a Hopping-Points SVD and Hough Transform-Based Line Detection Algorithm for Robot Localization and Mapping

    Directory of Open Access Journals (Sweden)

    Abhijeet Ravankar

    2016-05-01

    Full Text Available Line detection is an important problem in computer vision, graphics and autonomous robot navigation. Lines detected using a laser range sensor (LRS mounted on a robot can be used as features to build a map of the environment, and later to localize the robot in the map, in a process known as Simultaneous Localization and Mapping (SLAM. We propose an efficient algorithm for line detection from LRS data using a novel hopping-points Singular Value Decomposition (SVD and Hough transform-based algorithm, in which SVD is applied to intermittent LRS points to accelerate the algorithm. A reverse-hop mechanism ensures that the end points of the line segments are accurately extracted. Line segments extracted from the proposed algorithm are used to form a map and, subsequently, LRS data points are matched with the line segments to localize the robot. The proposed algorithm eliminates the drawbacks of point-based matching algorithms like the Iterative Closest Points (ICP algorithm, the performance of which degrades with an increasing number of points. We tested the proposed algorithm for mapping and localization in both simulated and real environments, and found it to detect lines accurately and build maps with good self-localization.

  13. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review

    OpenAIRE

    Trenchard, Hugh; Perc, Matjaz

    2016-01-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems including bacteria, spermatozoa, various aq...

  14. Effects of compositional defects on small polaron hopping in micas.

    Science.gov (United States)

    Rosso, Kevin M; Ilton, Eugene S

    2005-06-22

    Hartree-Fock calculations and electron transfer (ET) theory were used to model the effects of compositional defects on ET in the brucite-like octahedral sheet of mica. ET was modeled as an Fe(IIIII) valence interchange reaction across shared octahedral edges of the M2-M2 iron sublattice. The model entails the hopping of localized electrons and small polaron behavior. Hartree-Fock calculations indicate that substitution of F for structural OH bridges increases the reorganization energy lambda, decreases the electronic coupling matrix element V(AB), and thereby substantially decreases the hopping rate. The lambda increase arises from modification of the metal-ligand bond force constants, and the V(AB) decrease arises from reduction of superexchange interaction through anion bridges. Deprotonation of an OH bridge, consistent with a possible mechanism of maintaining charge neutrality during net oxidation, yields a net increase in the ET rate. Although substitution of Al or Mg for Fe in M1 sites distorts the structure of adjacent Fe-occupied M2 sites, the distortion has little net impact on ET rates through these M2 sites. Hence the main effect of Al or Mg substitution for Fe, should it occur in the M2 sublattice, is to block ET pathways. Collectively, these findings pave the way for larger-scale oxidation/reduction models to be constructed for realistic, compositionally diverse micas.

  15. Long-term oral administration of hop flower extracts mitigates Alzheimer phenotypes in mice.

    Directory of Open Access Journals (Sweden)

    Norio Sasaoka

    Full Text Available Coincident with the expanding population of aged people, the incidence of Alzheimer disease (AD is rapidly increasing in most advanced countries. At present, no effective prophylactics are available. Among several pathological mechanisms proposed for AD, the "amyloid hypothesis" has been most widely accepted, in which accumulation or deposition of Aβ is considered to be the initial event. Thus, prevention of Aβ production would be an ideal strategy for the treatment or prevention of AD. Aβ is produced via the proteolytic cleavage of its precursor protein, APP (amyloid precursor protein, by two different enzymes, β and γ-secretases. Indeed, inhibitors against either or both enzymes have been developed and tested for clinical efficacy. Based on the "amyloid hypothesis", we developed a luciferase-based screening method to monitor γ-secretase activity, screened more than 1,600 plant extracts, most of which have long been used in Chinese medicine, and observed that Hop extracts significantly inhibit Aβ production in cultured cells. A major component of the inhibitory activity was purified, and its chemical identity was determined by NMR to be Garcinielliptone HC. In vivo, oral administration of Hop extracts to AD model mice decreased Aβ depositions in the cerebral cortex of the parietal lobe, hippocampus, and artery walls (amyloid angiopathy in the brains. In a Morris water maze test, AD model mice that had daily consumed Hop extracts in their drinking water showed significant mitigation of memory impairment at ages of 9 and 12 months. Moreover, in the open field test oral administration of Hop extracts also prevented an emotional disturbance that appeared in the AD mice at 18 months. Despite lifelong consumption of Hop extracts, no deleterious side effects were observed at any age. These results support the "amyloid hypothesis", and indicate that Hop extract is a promising candidate for an effective prophylactic for AD.

  16. Results from HOPS: A multiwavelength census of Orion protostars

    Science.gov (United States)

    Fischer, W. J.; Megeath, S. T.; Stutz, A. M.; Tobin, J. J.; Ali, B.; Stanke, T.; Osorio, M.; Furlan, E.; HOPS Team; Orion Protostar Survey

    2013-02-01

    Surveys with the Spitzer and Herschel space observatories are now enabling the discovery and characterization of large samples of protostars in nearby molecular clouds, providing the observational basis for a detailed understanding of star formation in diverse environments. We are pursuing this goal with the Herschel Orion Protostar Survey (HOPS), which targets 328 Spitzer-identified protostars in the Orion molecular clouds, the largest star-forming region in the nearest 500 pc. The sample encompasses all phases of protostellar evolution and a wide range of formation environments, from dense clusters to relative isolation. With a grid of radiative transfer models, we fit the 1-870 μm spectral energy distributions (SEDs) of the protostars to estimate their envelope densities, cavity opening angles, inclinations, and total luminosities. After correcting the bolometric luminosities and temperatures of the sources for foreground extinction and inclination, we find a spread of several orders of magnitude in luminosity at all evolutionary states, a constant median luminosity over the more evolved stages, and a possible deficit of high-inclination, rapidly infalling envelopes among the Spitzer-identified sample. We have detected over 100 new sources in the Herschel images; some of them may fill this deficit. We also report results from modeling the pre- and post-outburst 1-870 μm SEDs of V2775 Ori (HOPS 223), a known FU Orionis outburster in the sample. It is the least luminous FU Ori star with a protostellar envelope.

  17. Evaluation of airborne methyl salicylate for improved conservation biological control of two-spotted spider mite and hop aphid in Oregon hop yards.

    Science.gov (United States)

    Woods, J L; James, D G; Lee, J C; Gent, D H

    2011-12-01

    The use of synthetic herbivore-induced plant volatiles (HIPV) to attract natural enemies has received interest as a tool to enhance conservation biological control (CBC). Methyl salicylate (MeSA) is a HIPV that is attractive to several key predators of two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Homoptera: Aphididae). A 2-year study was conducted to evaluate the recommended commercial use of MeSA in hop yards in Oregon. Slow-release MeSA dispensers were stapled to supporting poles in 0.5 ha plots and these plots were compared to a paired non-treated plot on each of three farms in 2008 and 2009. Across both years, there was a trend for reduced (range 40-91%) mean seasonal numbers of T. urticae in five of the six MeSA-baited plots. Stethorus spp., key spider mite predators, tended to be more numerous in MeSA-baited plots compared to control plots on a given farm. Mean seasonal densities of hop aphid and other natural enemies (e.g., Orius spp. and Anystis spp.) were similar between MeSA-treated and control plots. Variability among farms in suppression of two-spotted spider mites and attraction of Stethorus spp. suggests that the use of MeSA to enhance CBC of spider mites in commercial hop yards may be influenced by site-specific factors related to the agroecology of individual farms or seasonal effects that require further investigation. The current study also suggests that CBC of hop aphid with MeSA in this environment may be unsatisfactory.

  18. Exploiting Multi-user Diversity and Multi-hop Diversity in Dual-hop Broadcast Channels

    KAUST Repository

    Zafar, Ammar

    2013-05-21

    We propose joint user-and-hop scheduling over dual-hop block-fading broadcast channels in order to exploit multi-user diversity gains and multi-hop diversity gains all together. To achieve this objective, the first and second hops are scheduled opportunistically based on the channel state information. The joint scheduling problem is formulated as maximizing the weighted sum of the long term achievable rates of the users under a stability constraint, which means that in the long term the rate received by the relay should equal the rate transmitted by it, in addition to power constraints. We show that this problem is equivalent to a single-hop broadcast channel by treating the source as a virtual user with an optimal weight that maintains the stability constraint. We show how to obtain the source weight either off-line based on channel statistics or on real-time based on channel measurements. Furthermore, we consider special cases including the maximum sum-rate scheduler and the proportional fair scheduler. We also show how to extend the scheme into one that allows multiple user scheduling via superposition coding with successive decoding. Numerical results demonstrate that our proposed joint scheduling scheme enlarges the rate region as compared to scheduling schemes that exploit the diversity gains partially.

  19. Uudised : Pop-karneval. Hip-hop

    Index Scriptorium Estoniae

    2005-01-01

    Muusika- ja kunstikarnevalist "Beta Bubble" 1. apr. Tallinnas Von Krahlis. Pärnu taasühinenud hip-hop-bänd Noizmakaz (TommyBoy ja Alko) sõlmis lepingu plaadifirmaga Mindnote ja annab selle alt apr. keskel välja oma teise albumi "Valitud mõtted".1. apr. tuleb müügile Noizmakazi singel "Miski muu ei loe", debüüt "Social Poetry" ilmus aastal 2001

  20. Gender specific strategies in demanding hopping conditions.

    Science.gov (United States)

    Demirbüken, Ilkşan; Yurdalan, Saadet Ufuk; Savelberg, Hans; Meijer, Kenneth

    2009-01-01

    Difference in leg stiffness between females and males is considered to be a cause of higher rates of Anterior Cruciate Ligament injury in female athletes. Females are believed to have lower stiffness and as a consequence different recruitment strategies to adapt functional tasks. The aim of the current study was to evaluate how leg stiffness is tuned to demanding conditions. 22 healthy subjects (11 Male-11 Female; age: 20-43 years) participated in this study. Subjects performed two-legged hopping tasks (at their preferred rate, as fast as possible and with added mass of 10% bodyweight) on a force platform. Leg stiffness was calculated for each condition as the ratio between peak ground reaction force and vertical displacement of center of mass. In the preferred and added mass conditions males showed substantially higher leg stiffness than females (p= 0.006 and p = 0.002, respectively). When hopping as fast as possible the gender bias in leg stiffness disappeared (p = 0.880). Added mass had no significant effect on change in leg stiffness. Results have shown that females increased their leg stiffness more than males indicating they have no gender limiting capacity to reach objectives of higher demanding tasks (i.e.fastest hopping).The relationship between observed gender differences in leg stiffness and increased Anterior Cruciate Ligament injury rate in females requires further study. Key pointsLeg stiffness is an adaptable property of neuro musculoskeletal system to different functional loading conditions.Females can increase their leg stiffness more than males indicating they have no gender limiting capacity to reach objectives of higher demanding tasks as fastest hopping.

  1. Radio resource management scheme and outage analysis for network-assisted multi-hop D2D communications

    Directory of Open Access Journals (Sweden)

    Leila Melki

    2016-11-01

    Full Text Available In a cellular network it's very difficult to make spectrum resource more efficiently. Device-to-Device (D2D technology enables new service opportunities, and provides high throughput and reliable communication while reducing the base station load. For better total performance, short-range D2D links and cellular links share the same radio resource and the management of interference becomes a crucial task. Here we argue that single-hop D2D technology can be used to further improve cellular networks performance if the key D2D radio resource management algorithms are suitably extended to support multi-hop D2D communications. Aiming to establish a new paradigm for the analysis and design of multi-hop D2D communications, We propose a radio resource allocation for multi-hop D2D routes based on interference avoidance approach in LTE-A networks. On top of that, we investigate the outage probability of D2D communication. We first introduce a new definition of outage probability by considering the maximum distance to be allowable for single-hop transmission. Then we study and analyze the outage performance of a multi-hop D2D route. We derive the general closed form expression of outage probability of the multi-hop D2D routes. The results demonstrate that the D2D radio, sharing the same resources as the cellular network, provide higher capacity compared to pure cellular communication where all the data is transmitted through the base station. They also demonstrate that the new method of calculation of D2D multi hop outage probability has better performance than classical method defined in the literature.

  2. Performance analysis of decode-and-forward dual-hop optical spatial modulation with diversity combiner over atmospheric turbulence

    Science.gov (United States)

    Odeyemi, Kehinde O.; Owolawi, Pius A.; Srivastava, Viranjay M.

    2017-11-01

    Dual-hops transmission is a growing interest technique that can be used to mitigate against atmospheric turbulence along the Free Space Optical (FSO) communication links. This paper analyzes the performance of Decode-and-Forward (DF) dual-hops FSO systems in-conjunction with spatial modulation and diversity combiners over a Gamma-Gamma atmospheric turbulence channel using heterodyne detection. Maximum Ratio Combiner (MRC), Equal Gain Combiner (EGC) and Selection Combiner (SC) are considered at the relay and destination as mitigation tools to improve the system error performance. Power series expansion of modified Bessel function is used to derive the closed form expression for the end-to-end Average Pairwise Error Probability (APEP) expressions for each of the combiners under study and a tight upper bound on the Average Bit Error Rate (ABER) per hop is given. Thus, the overall end-to-end ABER for the dual-hops FSO system is then evaluated. The numerical results depicted that dual-hops transmission systems outperformed the direct link systems. Moreover, the impact of having the same and different combiners at the relay and destination are also presented. The results also confirm that the combination of dual hops transmission with spatial modulation and diversity combiner significantly improves the systems error rate with the MRC combiner offering an optimal performance with respect to variation in atmospheric turbulence, change in links average received SNR and link range of the system.

  3. Elevated Knee Joint Kinetics and Reduced Ankle Kinetics Are Present During Jogging and Hopping After Achilles Tendon Ruptures.

    Science.gov (United States)

    Willy, Richard W; Brorsson, Annelie; Powell, Hayley C; Willson, John D; Tranberg, Roy; Grävare Silbernagel, Karin

    2017-04-01

    rate of patellofemoral joint stress (LSI: 110.9%). Considerable side-to-side deficits in plantarflexor function were observed during walking, jogging, and hopping in patients after an Achilles tendon rupture. As a possible compensation, increased knee joint loads were present but only during jogging and hopping. These data suggest that after an Achilles tendon rupture, patients may be susceptible to greater mechanical loading of the knee during sporting tasks, regardless of surgical or nonsurgical treatment.

  4. Rethinking Pedagogy in Urban Spaces: Implementing Hip-Hop Pedagogy in the Urban Science Classroom

    Science.gov (United States)

    Adjapong, Edmund S.; Emdin, Christopher

    2015-01-01

    A significant amount of research regarding Hip-Hop Based Education (HHBE) fails to provide insight on how to incorporate elements of Hip-Hop into daily teaching practices; rather Hip-Hop based educators focus mainly on incorporating Hip-Hop culture into curricula. This study explores the benefits of using two specific Hip-Hop pedagogical practices…

  5. Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity

    OpenAIRE

    Ogden, Nick H.; Mechai, Samir; Margos, Gabriele

    2013-01-01

    The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic) changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R 0), and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors an...

  6. Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity.

    OpenAIRE

    Nicholas eOgden

    2013-01-01

    The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic) changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R0), and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors and...

  7. kinetics and mechanism of long-range pore ordering in anodic films on aluminium

    NARCIS (Netherlands)

    Napolskii, K.S.; Roslyakov, I. V.; Eliseev, A.A.; Byelov, D.|info:eu-repo/dai/nl/298392720; Petukhov, A.V.|info:eu-repo/dai/nl/304829196; Grigoryeva, N.A.; Bouwman, W.G.; Lukashin, A.V.; Chumakov, A. P.; Grigoriev, S.V.

    2011-01-01

    Anodic aluminum oxide has unique and highly attractive properties, including self-ordering of porous structure during anodization. Although anodization regimes leading to formation of highly ordered porous structures had been found experimentally, many aspects of the self-organization mechanism

  8. Simulating Muscle-Reflex Dynamics in a Simple Hopping Robot

    Science.gov (United States)

    Seyfarth, Andre; Kalveram, Karl Theodor; Geyer, Hartmut

    In legged systems, springy legs facilitate gaits with subsequent contact and flight phases. Here, we test whether electrical motors can generate leg behaviors suitable for stable hopping. We built a vertically operating sledge actuated by a motor-driven leg. The motor torque simulates either a linear leg spring or a muscle-reflex system. For stable hopping significant energy supply was required after midstance. This was achieved by enhancing leg stiffness or by continuously applying positive force feedback to the simulated muscle. The muscle properties combined with positive force feedback result in spring-like behavior which enables stable hopping with adjustable hopping height.

  9. Cu1-x Fe x O: hopping transport and ferromagnetism.

    Science.gov (United States)

    Nasir, Mohd; Islam, Rakibul; Ahmed, Md A; Ayaz, Saniya; Kumar, Gautham; Kumar, Sunil; Prajapat, C L; Roussel, Frederick; Biring, Sajal; Sen, Somaditya

    2017-09-01

    Single phase, sol-gel prepared Cu1-x Fe x O (0 ≤ x ≤ 0.125) powders are characterized in terms of structural, electronic and magnetic properties. Using dielectric and magnetic studies we investigate the coupling of electron and spin. The electrical conductivities and activation energies are studied with increasing Fe content. Modelling of experimental conductivity data emphasizes a single hopping mechanism for all samples except x = 0.125, which have two activation energies. Hole doping is confirmed by confirming a majority Fe3+ substitution of Cu2+ in CuO from X-ray photoelectron spectroscopy studies (XPS). Such a substitution results in stabilized ferromagnetism. Fe substitution introduces variation in coercivity as an intrinsic magnetic property in Fe-doped CuO, and not as a secondary impurity phase.

  10. Validity and reliability of HOP-Up: a questionnaire to evaluate physical activity environments in homes with preschool-aged children.

    Science.gov (United States)

    Cheng, Carolyn; Martin-Biggers, Jennifer; Quick, Virginia; Spaccarotella, Kim; Byrd-Bredbenner, Carol

    2016-08-18

    Early identification of physical activity (PA) opportunities in the home and neighborhood environment may help obesity prevention efforts in households with young children. This cross-sectional study's purpose was to develop a brief, easy-to-use, self-report inventory called Home Opportunities for Physical activity check-Up (HOP-Up), to evaluate the availability and accessibility of PA space and equipment in and near homes with preschool children, and establish its validity and reliability. The HOP-Up was field tested by two trained researchers and parents of preschool-aged children (n = 50; 71% white). To establish criterion validity, researchers were the 'gold standard' and visited participants' homes to assess their PA environments using the HOP-Up, while participants separately completed their HOP-Up. Two weeks later, parents completed the HOP-Up online for test-retest reliability. After minor survey refinements, exploratory and confirmatory factor analysis using a split-half cross validation procedure was conducted in a larger sample of participants (n = 655, 60% white) who completed the HOP-Up online to examine its factor structure. To establish convergent validity, correlations were conducted to compare HOP-Up scales from the factor solution generated with PA behavior and cognitions, and reported screen time. Intra-class correlations (ICCs) examining HOP-Up item agreement between researcher and parents revealed slight to substantial agreement (range 0.22 to 0.81) for all items. ICCs for all HOP-Up items ranged from fair to substantial agreement between parent responses at both time points (range 0.42 to 0.95). Exploratory factor analysis revealed a five factor solution (18 items), supported eigen values, scree plots, review for contextual sense, and confirmatory factor analysis. Additionally, there were significant (p environment-inside, outside, and the neighborhood- impacts preschool children's physical activity levels.

  11. Design and Dynamics Analysis of a Bio-Inspired Intermittent Hopping Robot for Planetary Surface Exploration

    Directory of Open Access Journals (Sweden)

    Long Bai

    2012-10-01

    Full Text Available A small, bio-inspired and minimally actuated intermittent hopping robot for planetary surface exploration is proposed in this paper. The robot uses a combined-geared six-bar linkage/spring mechanism, which has a possible rich trajectory and metamorphic characteristics and, due to this, the robot is able to recharge, lock/release and jump by using just a micro-power motor as the actuator. Since the robotic system has a closed-chain structure and employs underactuated redundant motion, the constrained multi-body dynamics are derived with time-varying driving parameters and ground unilateral constraint both taken into consideration. In addition, the established dynamics equations, mixed of higher order differential and algebraic expressions, are solved by the immediate integration algorithm. A prototype is implemented and experiments are carried out. The results show that the robot, using a micro-power motor as the actuator and solar cells as the power supply, can achieve a biomimetic multi-body hopping stance and a nonlinearly increasing driving force. Typically, the robot can jump a horizontal distance of about 1 m and a vertical height of about 0.3 m, with its trunk and foot moving stably during takeoff. In addition, the computational and experimental results are consistent as regards the hopping performance of the robot, which suggests that the proposed dynamics model and its solution have general applicability to motion prediction and the performance analysis of intermittent hopping robots.

  12. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport.

    Science.gov (United States)

    Riascos, A P; Mateos, José L

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  13. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport

    Science.gov (United States)

    Riascos, A. P.; Mateos, José L.

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  14. Characterization of the Migration of Hop Volatiles into Different Crown Cork Liner Polymers and Can Coatings.

    Science.gov (United States)

    Wietstock, Philip C; Glattfelder, Richard; Garbe, Leif-Alexander; Methner, Frank-Jürgen

    2016-04-06

    Absorption of hop volatiles by crown cork liner polymers and can coatings was investigated in beer during storage. All hop volatiles measured were prone to migrate into the closures, and the absorption kinetics was demonstrated to fit Fick's second law of diffusion well for a plane sheet. The extent and rate of diffusion were significantly dissimilar and were greatly dependent upon the nature of the volatile. Diffusion coefficients ranged from 1.32 × 10(-5) cm(2)/day (limonene) to 0.26 × 10(-5) cm(2)/day (α-humulene). The maximum amounts absorbed into the material at equilibrium were in the following order: limonene > α-humulene > trans-caryophyllene > myrcene ≫ linalool > α-terpineol > geraniol. With the application of low-density polyethylene (LDPE) liners with oxygen-scavenging functionality, oxygen-barrier liners made up from high-density polyethylene (HDPE) or liner polymers from a different manufacturer had no significant effect on the composition of hop volatiles in beers after prolonged storage of 55 days; however, significantly higher amounts of myrcene and limonene were found in the oxygen-barrier-type crown cork, while all other closures behaved similarly. Can coatings were demonstrated to absorb hop volatiles in a similar pattern as crown corks but to a lesser extent. Consequently, significantly higher percentages of myrcene were found in the beers.

  15. Comparison of four extraction methods for analysis of volatile hop-derived aroma compounds in beer.

    Science.gov (United States)

    Richter, Tobias M; Eyres, Graham T; Silcock, Patrick; Bremer, Phil J

    2017-11-01

    The volatile organic compound profile in beer is derived from hops, malt, yeast, and interactions between the ingredients, making it very diverse and complex. Due to the range and diversity of the volatile organic compounds present, the choice of the extraction method is extremely important for optimal sensitivity and selectivity. This study compared four extraction methods for hop-derived compounds in beer late hopped with Nelson Sauvin. Extraction capacity and variation were compared for headspace solid-phase micro extraction, stir bar sorptive extraction, headspace sorptive extraction, and solvent-assisted flavor evaporation. Generally, stir bar sorptive extraction was better suited for acids, headspace sorptive extraction for esters and aldehydes, while headspace solid-phase microextraction was less sensitive overall, extracting 40% fewer compounds. Solvent-assisted flavor evaporation with dichloromethane was not suitable for the extraction of hop-derived volatile organic compounds in beer, as the profile was strongly skewed towards alcohols and acids. Overall, headspace sorptive extraction is found to be best suited, closely followed by stir bar sorptive extraction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mortality in American Hip-Hop and Rap Recording Artists, 1987-2014.

    Science.gov (United States)

    Lawson, Carl J

    2015-12-01

    The deaths of American hip-hop and rap recording artists often receive considerable media attention. However, these artists' deaths have not been examined as a distinct group like the deaths of rock, classical, jazz, and pop music artists. This is a seminal epidemiological analysis on the deaths of an understudied group, American hip-hop and rap music recording artists. Media reports were analyzed of the deaths of American hip-hop and rap music recording artists that occurred from January 1, 1987 to December 31, 2014. The decedents' age, sex, race, cause of death, stage names, and city and state of death were recorded for analysis. The most commonly reported cause of death was homicide. The 280 deaths were categorized as homicide (55%), unintentional injury (13%), cardiovascular (7%), undetermined/undisclosed (7%), cancer (6%), other (5%), suicide (4%), and infectious disease (3%). The mean reported age at death was 30 yrs (range 15-75) and the median was 29 yrs; 97% were male and 92% were black. All but one of the homicides were committed with firearms. Homicide was the most commonly reported cause of death. Public health focus and guidance for hip-hop and rap recording artists should mirror that for African-American men and adolescent males ages 15-54 yrs, for whom the leading causes of death are homicide, unintentional injury, and heart disease. Given the preponderance of homicide deaths in this analysis, premature mortality reduction efforts should focus on violence prevention and conflict mitigation.

  17. A Double Rate Localization Algorithm with One Anchor for Multi-Hop Underwater Acoustic Networks.

    Science.gov (United States)

    Gao, Jingjie; Shen, Xiaohong; Zhao, Ruiqin; Mei, Haodi; Wang, Haiyan

    2017-04-28

    Localization is a basic issue for underwater acoustic networks (UANs). Currently, most localization algorithms only perform well in one-hop networks or need more anchors which are not suitable for the underwater environment. In this paper, we proposed a double rate localization algorithm with one anchor for multi-hop underwater acoustic networks (DRL). The algorithm firstly presents a double rate scheme which separates the localization procedure into two modes to increase the ranging accuracy in multi-hop UANs while maintaining the transmission rate. Then an optimal selection scheme of reference nodes was proposed to reduce the influence of references' topology on localization performance. The proposed DRL algorithm can be used in the multi-hop UANs to increase the localization accuracy and reduce the usage of anchor nodes. The simulation and experimental results demonstrated that the proposed DRL algorithm has a better localization performance than the previous algorithms in many aspects such as accuracy and communication cost, and is more suitable to the underwater environment.

  18. In and out of love with hip-hop: saliency of sexual scripts for young adult African American women in hip-hop and Black-oriented television.

    Science.gov (United States)

    Coleman, M Nicole; Butler, Ebony O; Long, Amanda M; Fisher, Felicia D

    2016-10-01

    Hip-hop media and Black-oriented reality television are powerful mechanisms for conveying and promoting stereotypes of Black women. Black women's sexuality is frequently presented as highly-salient in each medium. However, little is known about the impact of those images on Black women's sexuality and identity. The current study uses focus-group methodology to engage young adult Black in critical discussion of two predominant sexual scripts found in hip-hop music and Black-oriented reality television - the Freak and the Gold Digger. Analyses revealed shared and distinct aspects of each sexual script represented in both media and the impact of those scripts on participants' experiences. Implications for future research are discussed.

  19. Hip-Hop Is the Healer: Sense of Belonging and Diversity among Hip-Hop Collegians

    Science.gov (United States)

    Sulé, V. Thandi

    2016-01-01

    Sense of belonging is recognized as a factor contributing to persistence to graduation. Furthermore, interactional diversity is associated with learning and civic outcomes--touted higher education goals. Hip-hop culture, one of the most influential cultural creations of the mid-20th century, has succeeded in attracting devotees from diverse…

  20. Being Hipped to Their Hop: Tapping into Young Minds through Hip Hop Play

    Science.gov (United States)

    Broughton, Anthony

    2017-01-01

    Adults gain a wealth of knowledge from listening to the voices of children through intentional observations and interactions [Owocki, G., and Y. M. Goodman. 2002. "Kidwatching: Documenting Children's Literacy Development." Portsmouth: Heinemann]. Hip Hop play may provide optimal opportunities for teachers to tap into the young minds of…

  1. Pipefest hip hop -festivaalin markkinointiviestintä

    OpenAIRE

    Kallio, Timo

    2010-01-01

    Opinnäytetyöni aiheena oli Pipefest hip hop -festivaalien markkinointiviestinnän toteuttaminen. Olin ollut kävijänä tapahtumassa vuodesta 2003 lähtien, ja aloitettuani opinnot digitaalisen äänen ja kaupallisen musiikin suuntautumisvaihtoehdon linjalla, kiinnostuin tapahtuma- ja festivaalijärjestämisestä. Tutustuin tapahtumaa järjestävään tahoon ja aloin työstää Pipefestin markkinointiviestintää. Opintoihini kuuluneella tapahtumatuotannon kurssilla sain paljon oppia tapahtumatuotannosta t...

  2. Close-packed structure dynamics with finite-range interaction: computational mechanics with individual layer interaction.

    Science.gov (United States)

    Rodriguez-Horta, Edwin; Estevez-Rams, Ernesto; Lora-Serrano, Raimundo; Neder, Reinhard

    2017-09-01

    This is the second contribution in a series of papers dealing with dynamical models in equilibrium theories of polytypism. A Hamiltonian introduced by Ahmad & Khan [Phys. Status Solidi B (2000), 218, 425-430] avoids the unphysical assignment of interaction terms to fictitious entities given by spins in the Hägg coding of the stacking arrangement. In this paper an analysis of polytype generation and disorder in close-packed structures is made for such a Hamiltonian. Results are compared with a previous analysis using the Ising model. Computational mechanics is the framework under which the analysis is performed. The competing effects of disorder and structure, as given by entropy density and excess entropy, respectively, are discussed. It is argued that the Ahmad & Khan model is simpler and predicts a larger set of polytypes than previous treatments.

  3. Maser Source-Finding Methods in HOPS

    Science.gov (United States)

    Walsh, A. J.; Purcell, C.; Longmore, S.; Jordan, C. H.; Lowe, V.

    2012-12-01

    The H2O Southern Galactic Plane Survey (HOPS) has observed 100 deg2 of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12-mm band (19.5-27.5GHz). Perhaps the most important of these spectral lines is the 22.2-GHz water-maser transition. We describe the methods used to identify water-maser candidates and subsequent confirmation of the sources. Our methods involve a simple determination of likely candidates by searching peak emission maps, utilising the intrinsic nature of water-maser emission, spatially unresolved and spectrally narrow-lined. We estimate completeness limits and compare our method with results from the DUCHAMP source finder. We find that the two methods perform similarly. We conclude that the similarity in performance is due to the intrinsic limitation of the noise characteristics of the data. The advantages of our method are that it is slightly more efficient in eliminating spurious detections and is simple to implement. The disadvantage is that it is a manual method of finding sources and so is not practical on datasets much larger than HOPS, or for datasets with extended emission that needs to be characterised. We outline a two-stage method for the most efficient means of finding masers, using DUCHAMP.

  4. Long-range seasonal migration in insects: mechanisms, evolutionary drivers and ecological consequences.

    Science.gov (United States)

    Chapman, Jason W; Reynolds, Don R; Wilson, Kenneth

    2015-03-01

    Myriad tiny insect species take to the air to engage in windborne migration, but entomology also has its 'charismatic megafauna' of butterflies, large moths, dragonflies and locusts. The spectacular migrations of large day-flying insects have long fascinated humankind, and since the advent of radar entomology much has been revealed about high-altitude night-time insect migrations. Over the last decade, there have been significant advances in insect migration research, which we review here. In particular, we highlight: (1) notable improvements in our understanding of lepidopteran navigation strategies, including the hitherto unsuspected capabilities of high-altitude migrants to select favourable winds and orientate adaptively, (2) progress in unravelling the neuronal mechanisms underlying sun compass orientation and in identifying the genetic complex underpinning key traits associated with migration behaviour and performance in the monarch butterfly, and (3) improvements in our knowledge of the multifaceted interactions between disease agents and insect migrants, in terms of direct effects on migration success and pathogen spread, and indirect effects on the evolution of migratory systems. We conclude by highlighting the progress that can be made through inter-phyla comparisons, and identify future research areas that will enhance our understanding of insect migration strategies within an eco-evolutionary perspective. © 2015 John Wiley & Sons Ltd/CNRS.

  5. Potential African Substitutes for Hops in Tropical Beer Brewing ...

    African Journals Online (AJOL)

    Proximate analysis showed that these vegetables had protein and crude fibre values comparable to those of commercial hops. Fat content values were however much higher than those for hops with Grongonema latifolium having the highest values of 19.10%. Garcinia cola with a total resin value of 8.24% and an essential ...

  6. Toward Hip-Hop Pedagogies for Music Education

    Science.gov (United States)

    Kruse, Adam J.

    2016-01-01

    Music education scholarship in the areas of popular, vernacular, and participatory musicianship has grown in the past decades; however, music education research concerned specifically with hip-hop has been relatively scarce. Because hip-hop music can differ tremendously from the traditional western genres with which many music educators are most…

  7. Christian Hip Hop as Pedagogy: A South African Case Study

    Science.gov (United States)

    Abraham, Ibrahim

    2015-01-01

    Drawing on interviews with creators of Christian hip hop music in South Africa, this article demonstrates that this genre of popular music and youth culture is utilised as a form of pedagogy to transmit religious beliefs and values to contemporary youth. The pedagogical aspects of hip hop have been recognised in research on the topic, but the…

  8. Gap solitons in periodic Schrodinger lattice system with nonlinear hopping

    Directory of Open Access Journals (Sweden)

    Ming Cheng

    2016-10-01

    Full Text Available This article concerns the periodic discrete Schrodinger equation with nonlinear hopping on the infinite integer lattice. We obtain the existence of gap solitons by the linking theorem and concentration compactness method together with a periodic approximation technique. In addition, the behavior of such solutions is studied as $\\alpha\\to 0$. Notice that the nonlinear hopping can be sign changing.

  9. Being Hip-Hop: Beyond Skills and Songs

    Science.gov (United States)

    Kruse, Adam J.

    2016-01-01

    In this article, I offer four principles relevant to hip-hop cultures (keep it real, flip the script, make some noise, and stay fresh) and explore how these principles might affect music classrooms. I argue that a music classroom that works to keep it real, flip the script, make some noise, and stay fresh might go beyond teaching hip-hop skills…

  10. Towards a Pedagogy of Hip Hop in Urban Teacher Education

    Science.gov (United States)

    Bridges, Thurman

    2011-01-01

    This article draws from a qualitative study often Black male K-12 teachers from the Hip Hop Generation who are closely connected to Hip Hop culture and have been effective in addressing the academic and social needs of Black boys. Through an analysis of their social, educational and cultural experiences, this article highlights three organizing…

  11. Framing and Reviewing Hip-Hop Educational Research

    Science.gov (United States)

    Petchauer, Emery

    2009-01-01

    Hip-hop has become relevant to the field of education because of its implications for understanding language, learning, identity, curriculum, and other areas. This integrative review provides historical context and cohesion for the burgeoning and discursive body of hip-hop scholarship by framing it according to three heuristic categories and…

  12. Romani Music - Roma and the Hip-hop Culture

    OpenAIRE

    Dočkal, Tomáš

    2007-01-01

    This thesis is focused on Romani music and its importance for the Romani culture. It examines the popularity of hip-hop among the young Romani generation and Romani hip- hip production. It attempts to define the role of hip-hop culture in young Romanies' lives.

  13. Hip-Hop, the "Obama Effect," and Urban Science Education

    Science.gov (United States)

    Emdin, Christopher; Lee, Okhee

    2012-01-01

    Background/Context: With the ever increasing diversity of schools, and the persistent need to develop teaching strategies for the students who attend today's urban schools, hip-hop culture has been proposed to be a means through which urban youth can find success in school. As a result, studies of the role of hip-hop in urban education have grown…

  14. Investigating Cultural Collision: Educators' Perceptions of Hip-Hop Culture

    Science.gov (United States)

    Beachum, Floyd D.

    2013-01-01

    Hip-hop music has been embraced worldwide by youth, pummeled in the media for supposedly increasing social misery and hailed as a significant musical breakthrough. Hip-hop culture has transcended musical boundaries and now impacts speech, clothing, mannerisms, movies, websites, television programming, magazines, and energy drinks (Dyson, 2007;…

  15. Framing Hip Hop: New Methodologies for New Times

    Science.gov (United States)

    Dimitriadis, Greg

    2015-01-01

    This article revisits the central impulse behind early advocacy for ethnographic approaches to hip hop--that critics should try as much as possible to limit their own certainties around what hip hop can and might mean. While ethnographic approaches can engender the kinds of personal dislocations that allow for this negotiation, they do not…

  16. Hip Hop as Empowerment: Voices in El Alto, Bolivia

    Science.gov (United States)

    Tarifa, Ariana

    2012-01-01

    In response to neoliberal policies that have been in place since 1985, Bolivian young people have increasingly used hip hop music as a means of protest and to reclaim social and political participation. Hip hop in Latin America tells the story of the struggles that marginalized people have suffered, and speaks to the effects of international…

  17. Detailed balance, internal consistency, and energy conservation in fragment orbital-based surface hopping

    Science.gov (United States)

    Carof, Antoine; Giannini, Samuele; Blumberger, Jochen

    2017-12-01

    We have recently introduced an efficient semi-empirical non-adiabatic molecular dynamics method for the simulation of charge transfer/transport in molecules and molecular materials, denoted fragment orbital-based surface hopping (FOB-SH) [J. Spencer et al., J. Chem. Phys. 145, 064102 (2016)]. In this method, the charge carrier wavefunction is expanded in a set of charge localized, diabatic electronic states and propagated in the time-dependent potential due to classical nuclear motion. Here we derive and implement an exact expression for the non-adiabatic coupling vectors between the adiabatic electronic states in terms of nuclear gradients of the diabatic electronic states. With the non-adiabatic coupling vectors (NACVs) available, we investigate how different flavours of fewest switches surface hopping affect detailed balance, internal consistency, and total energy conservation for electron hole transfer in a molecular dimer with two electronic states. We find that FOB-SH satisfies detailed balance across a wide range of diabatic electronic coupling strengths provided that the velocities are adjusted along the direction of the NACV to satisfy total energy conservation upon a surface hop. This criterion produces the right fraction of energy-forbidden (frustrated) hops, which is essential for correct population of excited states, especially when diabatic couplings are on the order of the thermal energy or larger, as in organic semiconductors and DNA. Furthermore, we find that FOB-SH is internally consistent, that is, the electronic surface population matches the average quantum amplitudes, but only in the limit of small diabatic couplings. For large diabatic couplings, inconsistencies are observed as the decrease in excited state population due to frustrated hops is not matched by a corresponding decrease in quantum amplitudes. The derivation provided here for the NACV should be generally applicable to any electronic structure approach where the electronic

  18. Transport of hop aroma compounds across Caco-2 monolayers.

    Science.gov (United States)

    Heinlein, A; Metzger, M; Walles, H; Buettner, A

    2014-11-01

    Although being reported and used as a sedative remedy for several years, the bioactive principle of hop preparations is still not decisively clarified. Understanding absorption and transformation processes of potential physiologically active constituents is essential to evaluate the likeliness of biological effects on humans. Therefore, single hop aroma compounds as well as digestive transformation products thereof have been investigated in view of their human intestinal absorption, applying Caco-2 transport experiments as well as investigations on potential biotransformation processes. Selective and sensitive identification and quantification were thereby achieved by application of two-dimensional high resolution gas chromatography-mass spectrometry in conjunction with stable isotope dilution analysis, leading to the determination of apparent permeability values by different mathematical approaches considering sink and non-sink conditions. Overall, calculated permeability values ranged from 2.6 × 10(-6) to 1.8 × 10(-4) cm s(-1) with all mathematical approaches, indicating high absorption potential and almost complete bioavailability for all tested compounds with hydroxyl-functionalities. Considering this high permeability together with the high lipophilicity of these substances, a passive transcellular uptake route can be speculated. Investigated sesquiterpenes and β-myrcene showed flat absorption profiles while the investigated esters showed decreasing profiles. In view of the lipophilic and volatile nature of the investigated substances, special attention was paid to recovery and mass balance determination. Furthermore, in the course of the transport experiments of 1-octen-3-ol and 3-methyl-2-buten-1-ol, additional biotransformation products were observed, namely 3-octanone and 3-methyl-2-butenal, respectively. The absence of these additional substances in control experiments strongly indicates an intestinal first-pass metabolism of the

  19. Hip-Hop Is My Passport! Using Hip-Hop and Digital Literacies to Understand Global Citizenship Education

    Science.gov (United States)

    Horton, Akesha Monique

    2013-01-01

    Hip-hop has exploded around the world among youth. It is not simply an American source of entertainment; it is a global cultural movement that provides a voice for youth worldwide who have not been able to express their "cultural world" through mainstream media. The emerging field of critical hip-hop pedagogy has produced little…

  20. Hip Hop Culture's OGs: A Narrative Inquiry into the Intersection of Hip Hop Culture, Black Males and Their Schooling Experiences

    Science.gov (United States)

    Buchanan, Ian P.

    2013-01-01

    Using a critical race lens, this narrative study employs a focus group design to explore the intersections between black males, hip hop culture and schooling experiences. To provide a sociocultural grounding, this study first reviews the research literature around hip hop culture.s sociocultural development and its impact as a culture force that…

  1. Polarization switching and polarization mode hopping in quantum dot vertical-cavity surface-emitting lasers.

    Science.gov (United States)

    Olejniczak, Lukasz; Panajotov, Krassimir; Thienpont, Hugo; Sciamanna, Marc; Mutig, Alex; Hopfer, Friedhelm; Bimberg, Dieter

    2011-01-31

    We show experimentally that polarization mode hopping in quantum dot vertical cavity surface emitting lasers (VCSELs) takes place between nonorthogonal elliptically polarized modes. In contrast to quantum well VCSELs the average dwell time decreases with injection current. This decrease is by 8 orders of magnitude: from seconds to nanoseconds and is achieved without any modifications of the VCSEL internal anisotropies. The observed scaling happens in a range of currents as wide as 8 times the threshold value.

  2. Wifi, WiMax and LTE multi-hop mesh networks basic communication protocols and application areas

    CERN Document Server

    Wei, Hung-Yu; Dixit, Sudhir

    2013-01-01

    Wifi, WiMAX, and Cellular Multihop Networks presents an overview of WiFi-based and WiMAX-based multihop relay networks. As the first text to cover IEEE 802.16j multihop hop relay technology, this revolutionary resource explores the latest advances in multi-hop and ad-hoc networking. Not only does this reference provide the technological aspects, but also the applications for the emerging technology and architectural issues. Ranging from introductory material to advanced topics, this guidebook, plus PowerPoint slides, is essential for engineers, researchers, and students interested in

  3. Communication devices for network-hopping communications and methods of network-hopping communications

    Science.gov (United States)

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  4. IMMEDIATE EFFECT OF CERVICAL MANIPULATION ON PAIN AND RANGE OF MOTION IN PATIENTS WITH CHRONIC MECHANICAL NECK PAIN

    Directory of Open Access Journals (Sweden)

    Kabir Isah Mayana

    2017-06-01

    Full Text Available Background: Neck pain has been reported as a prevalent musculoskeletal disorder globally with more than half of the general population being affected once or more within their life span. Methods: A randomized clinical trial research design was used which investigated the immediate effect of cervical manipulation on neck pain and cervical range of motion among patients with chronic mechanical neck pain. 20 male and female participants between the ages of 26 to 60 years with chronic mechanical neck pain attending physiotherapy clinics were recruited. They were randomly assigned into two groups (A and B of 10 patients each. Group A received soft tissue massage, and cervical manipulation and group B served as the control group, and they received only soft tissue massage. There were two outcomes measured; Pain intensity was rated using visual analog scale (VAS before and immediately after the intervention. Pre and Post intervention measurements of cervical spine range of motion using Goniometer were also taken. Results: Findings of the study revealed significant immediate improvement of pain and Cervical Range of Motions (p<0.05 in all dimensions in the experimental group while Pain, flexion and right side Cervical flexion significantly improved in the control group. It was also found out after comparing the outcomes between the two groups that, the experimental group had significantly (p<0.05 better improvement than the control group in post-intervention pain, cervical flexion, cervical extension and cervical (right and left lateral rotations. Conclusion: Cervical manipulation is effective in immediate pain relief and improvement in cervical range of motion in patients with mechanical neck pain

  5. Bit-padding information guided channel hopping

    KAUST Repository

    Yang, Yuli

    2011-02-01

    In the context of multiple-input multiple-output (MIMO) communications, we propose a bit-padding information guided channel hopping (BP-IGCH) scheme which breaks the limitation that the number of transmit antennas has to be a power of two based on the IGCH concept. The proposed scheme prescribes different bit-lengths to be mapped onto the indices of the transmit antennas and then uses padding technique to avoid error propagation. Numerical results and comparisons, on both the capacity and the bit error rate performances, are provided and show the advantage of the proposed scheme. The BP-IGCH scheme not only offers lower complexity to realize the design flexibility, but also achieves better performance. © 2011 IEEE.

  6. Job-hopping and New Firm Survival

    DEFF Research Database (Denmark)

    Failla, Virgilio

    for this theory, little is known about the characteristics of this so called `balanced´ skills set. Do entrepreneurial outcomes of individuals presenting a highly varied work experiences differ from entrepreneurs with a less varied career' In particular, how do the characteristics of the entrepreneurs´ job...... is the right experience that enhances the new ventures´ performances. Fallick, Fleischman and Reibtzer (1996) argue that frequent job-hopping facilitates the rapid reallocation of resources toward firms with the best innovations. This could be the result of the fact that especially high quality individuals who...... employed in the start-up they founded. This initial evidence suggests that successful jack-of-all trades are people who do not wander across industries, but those who accumulate a variety of experiences by occupying different roles in the parent organization....

  7. Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity.

    Science.gov (United States)

    Ogden, Nick H; Mechai, Samir; Margos, Gabriele

    2013-01-01

    The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic) changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R 0), and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors and agent of Lyme disease as an example we then investigate what could be expected of the diversity of tick-borne pathogens during the process of range expansion, and compare this with what is currently being observed. Lastly we explore how historic population and range expansions and contractions could be reflected in the phylogeography of ticks and tick-borne pathogens seen in recent years, and conclude that combined study of currently changing tick and tick-borne pathogen ranges and diversity, with phylogeographic analysis, may help us better predict future patterns of invasion and diversity.

  8. Changing geographic ranges of ticks and tick-borne pathogens: drivers, mechanisms and consequences for pathogen diversity.

    Directory of Open Access Journals (Sweden)

    Nicholas eOgden

    2013-08-01

    Full Text Available The geographic ranges of ticks and tick-borne pathogens are changing due to global and local environmental (including climatic changes. In this review we explore current knowledge of the drivers for changes in the ranges of ticks and tick-borne pathogen species and strains via effects on their basic reproduction number (R0, and the mechanisms of dispersal that allow ticks and tick-borne pathogens to invade suitable environments. Using the expanding geographic distribution of the vectors and agent of Lyme disease as an example we then investigate what could be expected of the diversity of tick-borne pathogens during the process of range expansion, and compare this with what is currently being observed. Lastly we explore how historic population and range expansions and contractions could be reflected in the phylogeography of ticks and tick-borne pathogens seen in recent years, and conclude that combined study of currently changing tick and tick-borne pathogen ranges and diversity, with phylogeographic analysis, may help us better predict future patterns of invasion and diversity.

  9. Suppression of hop looper (Lepidoptera: Noctuidae) by the fungicide pyraclostrobin.

    Science.gov (United States)

    Woods, J L; Gent, D H

    2014-04-01

    The hop looper, Hypena humuli Harris, is a reemergent pest of hop that often requires treatment to mitigate crop damage. In 4 yr of field trials, plots treated with fungicides were observed to sustain less hop looper defoliation compared with nontreated plots. Further investigation revealed that abundance of hop looper and associated defoliation were reduced when the fungicide pyraclostrobin was applied in late July to early August. Two other fungicides possessing active ingredients in the same chemical family (quinone outside inhibitor) did not reduce abundance of hop looper or its defoliation. Pyraclostrobin is efficacious against powdery mildew diseases, and the application timing evaluated in these studies corresponds with a period of juvenile susceptibility of hop cones to the disease. Use of fungicides containing pyraclostrobin at this time may have the ancillary benefit of reducing hop looper damage, potentially obviating the need for broad-spectrum insecticides later in the season. Follow-up studies are warranted to determine whether pyraclostrobin may inhibit other lepidopteran species.

  10. What Is Hip-Hop-Based Education Doing in "Nice" Fields Such as Early Childhood and Elementary Education?

    Science.gov (United States)

    Love, Bettina L.

    2015-01-01

    Hip-Hop-Based Education (HHBE) has resulted in many positive educational outcomes, ranging from teaching academic skills to teaching critical reflection at secondary levels. Given what HHBE initiatives have accomplished, it is troubling that there is an absence of attention to these methods in education programs for elementary and early childhood…

  11. Investigation of Range Profiles from a Simplified Ship on Rough Sea Surface and Its Multipath Imaging Mechanisms

    Directory of Open Access Journals (Sweden)

    Siyuan He

    2012-01-01

    Full Text Available The range profiles of a two-dimension (2 D perfect electric conductor (PEC ship on a wind-driven rough sea surface are derived by performing an inverse discrete Fourier transform (IDFT on the wide band backscattered field. The rough sea surface is assuming to be a PEC surface. The back scattered field is computed based on EM numerical simulation when the frequencies are sampled between 100 MHz and 700 MHz. Considering the strong coupling interactions between the ship and sea, the complicated multipath effect to the range profile characteristics is fully analyzed based on the multipath imaging mechanisms. The coupling mechanisms could be explained by means of ray theory prediction and numerical extraction of the coupling currents. The comparison of the range profile locations between ray theory prediction and surface current simulation is implemented and analyzed in this paper. Finally, the influence of different sea states on the radar target signatures has been examined and discussed.

  12. Vegetation pattern formation in semiarid systems induced by long-range competition in the absence of facilitation mechanisms.

    Science.gov (United States)

    Martinez-Garcia, Ricardo; Calabrese, Justin M.; Hernandez-Garcia, Emilio; Lopez, Cristobal

    2014-05-01

    Regular patterns and spatial organization of vegetation have been observed in many arid and semiarid ecosystems worldwide, covering a diverse range of plant taxa and soil types. A key common ingredient in these systems is that plant growth is severely limited by water availability, and thus plants likely compete strongly for water. The study of such patterns is especially interesting because their features may reveal much about the underlying physical and biological processes that generated them in addition to giving information on the characteristics of the ecosystem. It is possible, for instance, to infer their resilience against anthropogenic disturbances or climatic changes that could cause abrupt shifts in the system and lead it to a desert state. Therefore much research has focused on identifying the underlying mechanisms that can produce spatial patterning in water-limited systems (Klausmeier, 1999). They are believed to arise from the interplay between long-range competition and facilitation processes acting at smaller distances (Borgogno et al., 2009). This combination of mechanisms is justified by arguing that water percolates more readily through the soil in vegetated areas (short range), and that plants compete for water resources over greater distances via long lateral roots (long range). However, recent studies have shown that even in the limit of local facilitation patterns may still appear (Martinez-Garcia et al., 2013). In this work (Martinez-Garcia et al., 2013b), we show that, under rather general conditions, long-range competition alone is the minimal ingredient to shape gapped and stripped vegetation patterns typical of models that also account for facilitation in addition to competition. To this end we propose a simple, general model for the dynamics of vegetation, which includes only long-range competition between plants. Competition is introduced through a nonlocal term, where the kernel function quantifies the intensity of the interaction

  13. Simultaneous Deep Tunneling and Classical Hopping for Hydrogen Diffusion on Metals

    Science.gov (United States)

    Fang, Wei; Richardson, Jeremy O.; Chen, Ji; Li, Xin-Zheng; Michaelides, Angelos

    2017-09-01

    Hydrogen diffusion on metals exhibits rich quantum behavior, which is not yet fully understood. Using simulations, we show that many hydrogen diffusion barriers can be categorized into those with parabolic tops and those with broad tops. With parabolic-top barriers, hydrogen diffusion evolves gradually from classical hopping, to shallow tunneling, to deep tunneling as the temperature (T ) decreases, and noticeable quantum effects persist at moderate T . In contrast, with broad-top barriers quantum effects become important only at low T and the classical-to-quantum transition is sharp, at which classical hopping and deep tunneling both occur. This coexistence indicates that more than one mechanism contributes to the quantum reaction rate. The conventional definition of the classical-to-quantum crossover T is invalid for the broad tops, and we give a new definition. Extending this, we propose a model to predict the transition T for broad-top diffusion, providing a general guide for theory and experiment.

  14. Dynamic Task Allocation in Multi-Hop Multimedia Wireless Sensor Networks with Low Mobility

    Directory of Open Access Journals (Sweden)

    Klaus Moessner

    2013-10-01

    Full Text Available This paper presents a task allocation-oriented framework to enable efficient in-network processing and cost-effective multi-hop resource sharing for dynamic multi-hop multimedia wireless sensor networks with low node mobility, e.g., pedestrian speeds. The proposed system incorporates a fast task reallocation algorithm to quickly recover from possible network service disruptions, such as node or link failures. An evolutional self-learning mechanism based on a genetic algorithm continuously adapts the system parameters in order to meet the desired application delay requirements, while also achieving a sufficiently long network lifetime. Since the algorithm runtime incurs considerable time delay while updating task assignments, we introduce an adaptive window size to limit the delay periods and ensure an up-to-date solution based on node mobility patterns and device processing capabilities. To the best of our knowledge, this is the first study that yields multi-objective task allocation in a mobile multi-hop wireless environment under dynamic conditions. Simulations are performed in various settings, and the results show considerable performance improvement in extending network lifetime compared to heuristic mechanisms. Furthermore, the proposed framework provides noticeable reduction in the frequency of missing application deadlines.

  15. A Low-Cost Time-Hopping Impulse Radio System for High Data Rate Transmission

    Directory of Open Access Journals (Sweden)

    Jinyun Zhang

    2005-03-01

    Full Text Available We present an efficient, low-cost implementation of time-hopping impulse radio that fulfills the spectral mask mandated by the FCC and is suitable for high-data-rate, short-range communications. Key features are (i all-baseband implementation that obviates the need for passband components, (ii symbol-rate (not chip rate sampling, A/D conversion, and digital signal processing, (iii fast acquisition due to novel search algorithms, and (iv spectral shaping that can be adapted to accommodate different spectrum regulations and interference environments. Computer simulations show that this system can provide 110 Mbps at 7–10 m distance, as well as higher data rates at shorter distances under FCC emissions limits. Due to the spreading concept of time-hopping impulse radio, the system can sustain multiple simultaneous users, and can suppress narrowband interference effectively.

  16. Characterization of hop pectins shows the presence of an arabinogalactan-protein

    NARCIS (Netherlands)

    Oosterveld, A.; Voragen, A.G.J.; Schols, H.A.

    2002-01-01

    Hop pectins were extracted from spent hops using acid extraction conditions and were characterized chemically. The acid extraction of spent hops resulted in a yield of 2°containing 59 f polysaccharides. The hop pectins under investigation had a relatively high molecular weight and an intrinsic

  17. Let Me Blow Your Mind: Hip Hop Feminist Futures in Theory and Praxis

    Science.gov (United States)

    Lindsey, Treva B.

    2015-01-01

    This essay brings together key theoretical interventions in hip-hop feminism to explore the continued, but undervalued, significance of hip-hop feminism in urban education. More specifically, the essay challenges narrow conceptualizations of the "hip hop subject" as Black and male by using hip-hop feminist theory to incorporate the lived…

  18. Performance Analysis of Millimeter-Wave Multi-hop Machine-to-Machine Networks Based on Hop Distance Statistics.

    Science.gov (United States)

    Jung, Haejoon; Lee, In-Ho

    2018-01-12

    As an intrinsic part of the Internet of Things (IoT) ecosystem, machine-to-machine (M2M) communications are expected to provide ubiquitous connectivity between machines. Millimeter-wave (mmWave) communication is another promising technology for the future communication systems to alleviate the pressure of scarce spectrum resources. For this reason, in this paper, we consider multi-hop M2M communications, where a machine-type communication (MTC) device with the limited transmit power relays to help other devices using mmWave. To be specific, we focus on hop distance statistics and their impacts on system performances in multi-hop wireless networks (MWNs) with directional antenna arrays in mmWave for M2M communications. Different from microwave systems, in mmWave communications, wireless channel suffers from blockage by obstacles that heavily attenuate line-of-sight signals, which may result in limited per-hop progress in MWNs. We consider two routing strategies aiming at different types of applications and derive the probability distributions of their hop distances. Moreover, we provide their baseline statistics assuming the blockage-free scenario to quantify the impact of blockages. Based on the hop distance analysis, we propose a method to estimate the end-to-end performances (e.g., outage probability, hop count, and transmit energy) of the mmWave MWNs, which provides important insights into mmWave MWN design without time-consuming and repetitive end-to-end simulation.

  19. Probability distributions of bed load particle velocities, accelerations, hop distances, and travel times informed by Jaynes's principle of maximum entropy

    Science.gov (United States)

    Furbish, David; Schmeeckle, Mark; Schumer, Rina; Fathel, Siobhan

    2016-01-01

    We describe the most likely forms of the probability distributions of bed load particle velocities, accelerations, hop distances, and travel times, in a manner that formally appeals to inferential statistics while honoring mechanical and kinematic constraints imposed by equilibrium transport conditions. The analysis is based on E. Jaynes's elaboration of the implications of the similarity between the Gibbs entropy in statistical mechanics and the Shannon entropy in information theory. By maximizing the information entropy of a distribution subject to known constraints on its moments, our choice of the form of the distribution is unbiased. The analysis suggests that particle velocities and travel times are exponentially distributed and that particle accelerations follow a Laplace distribution with zero mean. Particle hop distances, viewed alone, ought to be distributed exponentially. However, the covariance between hop distances and travel times precludes this result. Instead, the covariance structure suggests that hop distances follow a Weibull distribution. These distributions are consistent with high-resolution measurements obtained from high-speed imaging of bed load particle motions. The analysis brings us closer to choosing distributions based on our mechanical insight.

  20. Unraveling the differences of the hydrolytic activity of Trypanosoma cruzi trans-sialidase and Trypanosoma rangeli sialidase: a quantum mechanics-molecular mechanics modeling study.

    Science.gov (United States)

    Bueren-Calabuig, Juan A; Pierdominici-Sottile, Gustavo; Roitberg, Adrian E

    2014-06-05

    Chagas' disease, also known as American trypanosomiasis, is a lethal, chronic disease that currently affects more than 10 million people in Central and South America. The trans-sialidase from Trypanosoma cruzi (T. cruzi, TcTS) is a crucial enzyme for the survival of this parasite: sialic acids from the host are transferred to the cell surface glycoproteins of the trypanosome, thereby evading the host's immune system. On the other hand, the sialidase of T. rangeli (TrSA), which shares 70% sequence identity with TcTS, is a strict hydrolase and shows no trans-sialidase activity. Therefore, TcTS and TrSA represent an excellent framework to understand how different catalytic activities can be achieved with extremely similar structures. By means of combined quantum mechanics-molecular mechanics (QM/MM, SCC-DFTB/Amberff99SB) calculations and umbrella sampling simulations, we investigated the hydrolysis mechanisms of TcTS and TrSA and computed the free energy profiles of these reactions. The results, together with our previous computational investigations, are able to explain the catalytic mechanism of sialidases and describe how subtle differences in the active site make TrSA a strict hydrolase and TcTS a more efficient trans-sialidase.

  1. Muscle coordination limits efficiency and power output of human limb movement under a wide range of mechanical demands

    Science.gov (United States)

    Wakeling, James M.

    2015-01-01

    This study investigated the influence of cycle frequency and workload on muscle coordination and the ensuing relationship with mechanical efficiency and power output of human limb movement. Eleven trained cyclists completed an array of cycle frequency (cadence)-power output conditions while excitation from 10 leg muscles and power output were recorded. Mechanical efficiency was maximized at increasing cadences for increasing power outputs and corresponded to muscle coordination and muscle fiber type recruitment that minimized both the total muscle excitation across all muscles and the ineffective pedal forces. Also, maximum efficiency was characterized by muscle coordination at the top and bottom of the pedal cycle and progressive excitation through the uniarticulate knee, hip, and ankle muscles. Inefficiencies were characterized by excessive excitation of biarticulate muscles and larger duty cycles. Power output and efficiency were limited by the duration of muscle excitation beyond a critical cadence (120–140 rpm), with larger duty cycles and disproportionate increases in muscle excitation suggesting deteriorating muscle coordination and limitations of the activation-deactivation capabilities. Most muscles displayed systematic phase shifts of the muscle excitation relative to the pedal cycle that were dependent on cadence and, to a lesser extent, power output. Phase shifts were different for each muscle, thereby altering their mechanical contribution to the pedaling action. This study shows that muscle coordination is a key determinant of mechanical efficiency and power output of limb movement across a wide range of mechanical demands and that the excitation and coordination of the muscles is limited at very high cycle frequencies. PMID:26445873

  2. Muscle coordination limits efficiency and power output of human limb movement under a wide range of mechanical demands.

    Science.gov (United States)

    Blake, Ollie M; Wakeling, James M

    2015-12-01

    This study investigated the influence of cycle frequency and workload on muscle coordination and the ensuing relationship with mechanical efficiency and power output of human limb movement. Eleven trained cyclists completed an array of cycle frequency (cadence)-power output conditions while excitation from 10 leg muscles and power output were recorded. Mechanical efficiency was maximized at increasing cadences for increasing power outputs and corresponded to muscle coordination and muscle fiber type recruitment that minimized both the total muscle excitation across all muscles and the ineffective pedal forces. Also, maximum efficiency was characterized by muscle coordination at the top and bottom of the pedal cycle and progressive excitation through the uniarticulate knee, hip, and ankle muscles. Inefficiencies were characterized by excessive excitation of biarticulate muscles and larger duty cycles. Power output and efficiency were limited by the duration of muscle excitation beyond a critical cadence (120-140 rpm), with larger duty cycles and disproportionate increases in muscle excitation suggesting deteriorating muscle coordination and limitations of the activation-deactivation capabilities. Most muscles displayed systematic phase shifts of the muscle excitation relative to the pedal cycle that were dependent on cadence and, to a lesser extent, power output. Phase shifts were different for each muscle, thereby altering their mechanical contribution to the pedaling action. This study shows that muscle coordination is a key determinant of mechanical efficiency and power output of limb movement across a wide range of mechanical demands and that the excitation and coordination of the muscles is limited at very high cycle frequencies. Copyright © 2015 the American Physiological Society.

  3. Hops (Humulus lupulus) Content in Beer Modulates Effects of Beer on the Liver After Acute Ingestion in Female Mice.

    Science.gov (United States)

    Landmann, Marianne; Sellmann, Cathrin; Engstler, Anna Janina; Ziegenhardt, Doreen; Jung, Finn; Brombach, Christine; Bergheim, Ina

    2017-01-01

    Using a binge-drinking mouse model, we aimed to determine whether hops (Humulus lupulus) in beer is involved in the less damaging effects of acute beer consumption on the liver in comparison with ethanol. Female C57BL/6 J mice were either fed one iso-alcoholic and iso-caloric bolus dose of ethanol, beer, beer without hops (6 g ethanol/kg body weight) or an iso-caloric bolus of maltodextrin control solution. Markers of steatosis, intestinal barrier function, activation of toll-like receptor 4 signaling cascades, lipid peroxidation and lipogenesis were determined in liver, small intestine and plasma 2 h and 12 h after acute alcohol ingestion. Alcohol-induced hepatic fat accumulation was significantly attenuated in mice fed beer whereas in those fed beer without hops, hepatic fat accumulation was similar to that found in ethanol-fed mice. While markers of intestinal barrier function e.g. portal endotoxin levels and lipogenesis only differed slightly between groups, hepatic concentrations of myeloid differentiation primary response gene 88, inducible nitric oxide synthase (iNOS) and plasminogen-activator inhibitor 1 protein as well as of 4-hydroxynonenal and 3-nitrotyrosine protein adducts were similarly elevated in livers of mice fed ethanol or beer without hops when compared with controls. Induction of these markers was markedly attenuated in mice fed hops-containing beer. Taken together, our data suggest that hops in beer markedly attenuated acute alcohol-induced liver steatosis in female mice through mechanisms involving a suppression of iNOS induction in the liver. © The Author 2016. Medical Council on Alcohol and Oxford University Press. All rights reserved.

  4. DNA binding by FOXP3 domain-swapped dimer suggests mechanisms of long-range chromosomal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yongheng; Chen, Chunxia; Zhang, Zhe; Liu, Chun-Chi; Johnson, Matthew E.; Espinoza, Celso A.; Edsall, Lee E.; Ren, Bing; Zhou, Xianghong Jasmine; Grant, Struan F.A.; Wells, Andrew D.; Chen, Lin (LICR); (UPENN); (USC)

    2015-01-07

    FOXP3 is a lineage-specific transcription factor that is required for regulatory T cell development and function. In this study, we determined the crystal structure of the FOXP3 forkhead domain bound to DNA. The structure reveals that FOXP3 can form a stable domain-swapped dimer to bridge DNA in the absence of cofactors, suggesting that FOXP3 may play a role in long-range gene interactions. To test this hypothesis, we used circular chromosome conformation capture coupled with high throughput sequencing (4C-seq) to analyze FOXP3-dependent genomic contacts around a known FOXP3-bound locus, Ptpn22. Our studies reveal that FOXP3 induces significant changes in the chromatin contacts between the Ptpn22 locus and other Foxp3-regulated genes, reflecting a mechanism by which FOXP3 reorganizes the genome architecture to coordinate the expression of its target genes. Our results suggest that FOXP3 mediates long-range chromatin interactions as part of its mechanisms to regulate specific gene expression in regulatory T cells.

  5. Field dependence of hopping mobility: Lattice models against spatial disorder

    Science.gov (United States)

    Oelerich, J. O.; Nenashev, A. V.; Dvurechenskii, A. V.; Gebhard, F.; Baranovskii, S. D.

    2017-11-01

    The theoretical description of the effect of the electric field F on the hopping mobility μ belongs to the not-yet-resolved problems related to charge transport in disordered materials. An often proposed solution is to simulate hopping transport via sites placed on regular grids and to fit the results by phenomenological equations. This approach currently dominates the theoretical research of hopping transport in organic disordered semiconductors. We show that the dependence μ (F ) in the case of regular grids can drastically differ from that in systems with spatial disorder. While μ increases with F on lattices, it can decrease in random systems with the same material parameters. Moreover, the material parameters responsible for the dependence μ (F ) on lattices differ from those responsible for μ (F ) in spatially disordered systems, which makes lattice models inappropriate for studying the field dependence of the hopping mobility.

  6. Two-Hop Secure Communication Using an Untrusted Relay

    National Research Council Canada - National Science Library

    He, Xiang; Yener, Aylin

    2009-01-01

    .... Yet, the information it relays needs to be kept secret from it. In this two-hop communication scenario, where the use of the untrusted relay node is essential, we find that a positive secrecy rate is achievable...

  7. Hip Hop Dance Experience Linked to Sociocognitive Ability

    National Research Council Canada - National Science Library

    Justin W Bonny; Jenna C Lindberg; Marc C Pacampara

    2017-01-01

    .... In the present study, we examined whether experience in a different activity, hip hop dance, is also linked to cognitive abilities connected with STEM skills as well as social cognition ability...

  8. Hopping trajectory optimization for surface exploration on small bodies

    Science.gov (United States)

    Liu, Yanjie; Zhu, Shengying; Cui, Pingyuan; Yu, Zhengshi; Zong, Hua

    2017-07-01

    Surface exploration is an important way to improve the understanding of small bodies. Considering the irregular and weak gravity field near a small body, the movement of the surface explorer is generally achieved by hopping. In this paper, a guidance algorithm method based on convex optimization approach for pinpoint hopping movement on a small body is developed in order to improve the stability and accuracy of surface exploration. We formulate a fuel-optimal control problem for the single pinpoint hopping and convert it into a second-order cone programming (SOCP) problem which can be solved effectively by primal-dual-interior points method. A multi-hopping scenario is also proposed for the long-distance transfer. To certificate the performance of the proposed guidance algorithm, a full set of simulations are conducted and the effectiveness are analyzed.

  9. Hip hop jako kulturní styl, jeho spicifika a vliv na teenagery

    OpenAIRE

    Pospíšil, Jan

    2008-01-01

    This thesis involves history of hip hop, its specifics and elements, it talks about influence of hip hip subculture on teenagers and points to positive and negative aspects connected to this culture style. In this way is work sectionalized into chapters. First part talks about history of hip hop, connection between religion and hip hop and also about Czech hip hop. Second part specifies on main elements of hip hop culture as DJing, MCing, breakdance, beatbox and graffiti. Last part focuses on...

  10. Charge Transport Mechanism in Thin Cuticles Holding Nandi Flame Seeds

    Directory of Open Access Journals (Sweden)

    Wycliffe K. Kipnusu

    2009-01-01

    Full Text Available Metal-sample-metal sandwich configuration has been used to investigate DC conductivity in 4 m thick Nandi flame [Spathodea campanulata P. Beauv.] seed cuticles. - characteristics showed ohmic conduction at low fields and space charge limited current at high fields. Charge mobility in ohmic region was 4.06×10−5(m2V−1s−1. Temperature-dependent conductivity measurements have been carried out in the temperature range 320 K 450 K. Activation energy within a temperature of 320 K–440 K was about 0.86 eV. Variable range hopping (VRH is the main current transport mechanism at the range of 330–440 K. The VRH mechanism was analyzed based on Mott theory and the Mott parameters: density of localized states near the Fermi-level N(≈9.04×1019(eV−1cm−3 and hopping distance ≈1.44×10−7 cm, while the hopping energy ( was in the range of 0.72 eV–0.98 eV.

  11. Low Power Multi-Hop Networking Analysis in Intelligent Environments

    Directory of Open Access Journals (Sweden)

    Josu Etxaniz

    2017-05-01

    Full Text Available Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More precisely, the paper combines the multi-hop networking with Bluetooth technology and a quality of service (QoS metric, the latency. Bluetooth is a radio license-free worldwide communication standard that makes low power multi-hop wireless networking available. It establishes piconets (point-to-point and point-to-multipoint links and scatternets (multi-hop networks. As a result, many Bluetooth nodes can be interconnected to set up ambient intelligent networks. Then, this paper presents the results of the investigation on multi-hop latency with park and sniff Bluetooth low power modes conducted over the hardware test bench previously implemented. In addition, the empirical models to estimate the latency of multi-hop communications over Bluetooth Asynchronous Connectionless Links (ACL in park and sniff mode are given. The designers of devices and networks for intelligent systems will benefit from the estimation of the latency in Bluetooth multi-hop communications that the models provide.

  12. The Hip-Hop club scene: Gender, grinding and sex.

    Science.gov (United States)

    Muñoz-Laboy, Miguel; Weinstein, Hannah; Parker, Richard

    2007-01-01

    Hip-Hop culture is a key social medium through which many young men and women from communities of colour in the USA construct their gender. In this study, we focused on the Hip-Hop club scene in New York City with the intention of unpacking narratives of gender dynamics from the perspective of young men and women, and how these relate to their sexual experiences. We conducted a three-year ethnographic study that included ethnographic observations of Hip-Hop clubs and their social scene, and in-depth interviews with young men and young women aged 15-21. This paper describes how young people negotiate gender relations on the dance floor of Hip-Hop clubs. The Hip-Hop club scene represents a context or setting where young men's masculinities are contested by the social environment, where women challenge hypermasculine privilege and where young people can set the stage for what happens next in their sexual and emotional interactions. Hip-Hop culture therefore provides a window into the gender and sexual scripts of many urban minority youth. A fuller understanding of these patterns can offer key insights into the social construction of sexual risk, as well as the possibilities for sexual health promotion, among young people in urban minority populations.

  13. Low Power Multi-Hop Networking Analysis in Intelligent Environments.

    Science.gov (United States)

    Etxaniz, Josu; Aranguren, Gerardo

    2017-05-19

    Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More precisely, the paper combines the multi-hop networking with Bluetooth technology and a quality of service (QoS) metric, the latency. Bluetooth is a radio license-free worldwide communication standard that makes low power multi-hop wireless networking available. It establishes piconets (point-to-point and point-to-multipoint links) and scatternets (multi-hop networks). As a result, many Bluetooth nodes can be interconnected to set up ambient intelligent networks. Then, this paper presents the results of the investigation on multi-hop latency with park and sniff Bluetooth low power modes conducted over the hardware test bench previously implemented. In addition, the empirical models to estimate the latency of multi-hop communications over Bluetooth Asynchronous Connectionless Links (ACL) in park and sniff mode are given. The designers of devices and networks for intelligent systems will benefit from the estimation of the latency in Bluetooth multi-hop communications that the models provide.

  14. Hip abduction-adduction strength and one-leg hop tests: test-retest reliability and relationship to function in elite ice hockey players.

    Science.gov (United States)

    Kea, J; Kramer, J; Forwell, L; Birmingham, T

    2001-08-01

    Single group, test-retest. To determine: (1) hip abduction and adduction torques during concentric and eccentric muscle actions, (2) medial and lateral one-leg hop distances, (3) the test-retest reliability of these measurements, and (4) the relationship between isokinetic measures of hip muscle strength and hop distances in elite ice hockey players. The skating motion used in ice hockey requires strong contractions of the hip and knee musculature. However, baseline scores for hip strength and hop distances, their test-retest reliability, and measures of the extent to which these tests are related for this population are not available. The dominant leg of 27 men (mean age 20 +/- 3 yrs) was tested on 2 occasions. Hip abduction and adduction movements were completed at 60 degrees.s(-1) angular velocity, with the subject lying on the non-test side and the test leg moving vertically in the subject's coronal plane. One-leg hops requiring jumping from and landing on the same leg without losing balance were completed in the medial and lateral directions. Hip adduction torques were significantly greater than abduction torques during both concentric and eccentric muscle actions, while no significant difference was observed between medial and lateral hop distances. Although hop test scores produced excellent ICCs (> 0.75) when determined using scores on 1 occasion, torques needed to be averaged over 2 test occasions to reach this level. Correlations between the strength and hop tests ranged from slight to low (r = -0.26 to 0.27) and were characterized by wide 95% confidence intervals (-0.54 to 0.61). Isokinetic tests of hip abduction and adduction did not provide a strong indication of performance during sideways hop tests. Although isokinetic tests can provide a measure of muscular strength under specific test conditions, they should not be relied upon as a primary indicator of functional abilities or readiness to return to activity.

  15. CORVET and HOPS tethering complexes - coordinators of endosome and lysosome fusion.

    Science.gov (United States)

    Balderhaar, Henning J kleine; Ungermann, Christian

    2013-03-15

    Protein and lipid transport along the endolysosomal system of eukaryotic cells depends on multiple fusion and fission events. Over the past few years, the molecular constituents of both fission and fusion machineries have been identified. Here, we focus on the mechanism of membrane fusion at endosomes, vacuoles and lysosomes, and in particular on the role of the two homologous tethering complexes called CORVET and HOPS. Both complexes are heterohexamers; they share four subunits, interact with Rab GTPases and soluble NSF attachment protein receptors (SNAREs) and can tether membranes. Owing to the presence of specific subunits, CORVET is a Rab5 effector complex, whereas HOPS can bind efficiently to late endosomes and lysosomes through Rab7. Based on the recently described overall structure of the HOPS complex and a number of in vivo and in vitro analyses, important insights into their function have been obtained. Here, we discuss the general function of both complexes in yeast and in metazoan cells in the context of endosomal biogenesis and maturation.

  16. Dielectric relaxation and localized electron hopping in colossal dielectric (Nb,In)-doped TiO2 rutile nanoceramics.

    Science.gov (United States)

    Tsuji, Kosuke; Han, HyukSu; Guillemet-Fritsch, Sophie; Randall, Clive A

    2017-03-28

    Dielectric spectroscopy was performed on a Nb and In co-doped rutile TiO2 nano-crystalline ceramic (n-NITO) synthesized by a low-temperature spark plasma sintering (SPS) technique. The dielectric properties of the n-NITO were not largely affected by the metal electrode contacts. Huge dielectric relaxation was observed at a very low temperature below 35 K. Both the activation energy and relaxation time suggested that the electronic hopping motion is the underlying mechanism responsible for the colossal dielectric permittivity (CP) and its relaxation, instead of the internal barrier layer effect or a dipolar relaxation. With Havriliak-Negami (H-N) fitting, a relaxation time with a large distribution of dielectric relaxations was revealed. The broad distributed relaxation phenomena indicated that Nb and In were involved, controlling the dielectric relaxation by modifying the polarization mechanism and localized states. The associated distribution function is calculated and presented. The frequency-dependent a.c. conductance is successfully explained by a hopping conduction model of the localized electrons with the distribution function. It is demonstrated that the dielectric relaxation is strongly correlated with the hopping electrons in the localized states. The CP in SPS n-NITO is then ascribed to a hopping polarization.

  17. Hip Hop Syllabus: AME/MUS 303 Hip Hop: Art, Culture, and Politics

    Directory of Open Access Journals (Sweden)

    Sarah Hentges

    2013-10-01

    Full Text Available This syllabus represents a course taught online through the University of Maine at Augusta in the fall of 2011 (and every otheryear thereafter. Critical pedagogy can be a challenge in any classroom, and the challenges in an online classroom are compounded. However, the subject matter and approach of Hip Hop can be a powerful tool in teaching students critical thinking skills as well in laying a foundation for interdisciplinary and intersectional theory; here these elements are represented through curriculum—the themes, texts, contexts,approaches, structure, and assignments.

  18. Assimilation and Hip-Hop : Interethnic Relations and the Americanization of New Immigrants in Hip-Hop Culture

    OpenAIRE

    Aahlin, Audun Kjus

    2013-01-01

    The conflict thesis and the segmented assimilation theory account for two of the most significant trends in American immigration and ethnicity studies. Both of these major theoretical styles are utterly pessimistic towards interethnic relations in the United States and assimilation into African American urban culture. I have asked in this thesis if the experiences and the history of hip-hop culture can counterbalance these negative interpretations of interethnic relations. Hip-hop culture has...

  19. SDN-based path hopping communication against eavesdropping attack

    Science.gov (United States)

    Zhang, Chuanhao; Bu, Youjun; Zhao, Zheng

    2016-10-01

    Network eavesdropping is one of the most popular means used by cyber attackers, which has been a severe threat to network communication security. Adversaries could capture and analyze network communication data from network nodes or links, monitor network status and steal sensitive data such as username and password etc. Traditional network usually uses static network configuration, and existing defense methods, including firewall, IDS, IPS etc., cannot prevent eavesdropping, which has no distinguishing characteristic. Network eavesdropping become silent during most of the time of the attacking process, which is why it is difficult to discover and to defend. But A successful eavesdropping attack also has its' precondition, which is the target path should be relatively stable and has enough time of duration. So, In order to resolve this problem, it has to work on the network architecture. In this paper, a path hopping communication(PHC) mechanism based on Software Define Network (SDN) was proposed to solve this problem. In PHC, Ends in communication packets as well as the routing paths were changed dynamically. Therefore, the traffic would be distributed to multiple flows and transmitted along different paths. so that Network eavesdropping attack could be prevented effectively. It was concluded that PHC was able to increase the overhead of Network eavesdropping, as well as the difficulty of communication data recovery.

  20. Mechanical and Microstructural Investigation of Dual Phase Stainless Steel (LDX2101) under a wide range of strain rates

    Science.gov (United States)

    Ameri, Ali; Escobedo-Diaz, Juan; Ashraf, Mahmud; Brown, Andrew; Hazell, Paul; Hutchison, Wayne; Quadir, Zakaria

    2017-06-01

    The mechanical response and the microstructural evolution of lean duplex stainless steel 2101 (LDSS 2101) under a wide range of strain rates has been investigated. Experimental testing spanned from quasistatic, high strain-rate (Split Hopkinson Pressure Bar) and shock loading. The microstructural changes, e.g. phase transformation and grain rotation, texture and substructure evolution, were investigated by optical microscopy, X-ray diffraction (XRD) and electron-backscattered diffraction (EBSD). A significant increase in the yield stress with increasing strain rate was observed. The plastic deformation, e.g. work hardening rate, was also depended on the strain-rate. The threshold stress for the iron-epsilon phase transformation was obtained from free surface velocity measurements and the retained high pressure phase was assessed by XRD measurements.

  1. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Energy Technology Data Exchange (ETDEWEB)

    Drakakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kymakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Tzagkarakis, G.; Louloudakis, D.; Katharakis, M. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kenanakis, G. [Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas, Heraklion (Greece); Suchea, M.; Tudose, V. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Chemistry Faculty, “Al.I.Cuza” University of Iasi, Iasi (Romania); Koudoumas, E., E-mail: koudoumas@staff.teicrete.gr [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece)

    2017-03-15

    Highlights: • Optimum paint contents should be chosen so that homogeneous and uniform nanocomposite layers exist exhibiting effective electromagnetic shielding. • The electromagnetic shielding in the frequency range studied comes mainly from absorption and increases with frequency. • Reflection reduces with increasing frequency, the decrease rate being smaller than that of the increase in absorption. • The shielding efficiency depends on both conductivity and thickness, the first dependence being more pronounced. - Abstract: We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4–20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  2. Influence of the quark-gluon string fusion mechanism on long-range rapidity correlations and fluctuations

    Science.gov (United States)

    Andronov, E. V.

    2015-10-01

    Multiparticle production in soft hadronic interactions can be successfully described in the framework of the color-string approach, which will probably be derived from the first principles of chromodynamics in the future. A fundamental property of this approach is the translation invariance of the rapidity spectrum of charged particles produced by one source at high energies. This symmetry results in the appearance of long-range rapidity correlations through event-by-event fluctuations of the number and/or type of strings. We describe the behavior of correlations between multiplicities ( n-n) and between the transverse momentum and multiplicities ( pt-n) of charged particles with the mechanism of forming sources of two types taken into account. We obtain an exact analytic expression for the ( n-n)-correlation coefficient. Because no exact solution can be obtained for the ( pt-n)-correlation coefficient, we propose an effective approximation that significantly simplifies numerical computations. We verify all these results by direct simulation using the Monte Carlo method. We also investigate how the fusion mechanism influences the behavior of strongly intensive variables characterizing the multiplicity fluctuations in two rapidity windows.

  3. From "They" Science to "Our" Science: Hip Hop Epistemology in STEAM Education

    Science.gov (United States)

    Dolberry, Maurice E.

    Hip hop has moved from being considered a type of music into being understood as a culture in which a prominent type of music originates. Hip hop culture has a philosophy and epistemological constructs as well. This study analyzed those constructs to determine how conceptions of science factor in hip hop worldviews. Pedagogical models in culturally responsive teaching and Science, Technology, Engineering, Arts, and Mathematics (STEAM) education were also examined to discern their philosophical connections with hip hop culture. These connections were used to create two theoretical models. The first one, Hip Hop Science, described how scientific thought functions in hip hop culture. The second model, Hip Hop STEAM Pedagogy, proposes how hip hop culture can inform STEAM teaching practices. The study began by using Critical Race Theory to create a theoretical framework proposing how the two theoretical models could be derived from the philosophical and pedagogical concepts. Content analysis and narrative inquiry were used to analyze data collected from scholarly texts, hip hop songs, and interviews with hip hop-responsive educators. The data from these sources were used initially to assess the adequacy of the proposed theoretical framework, and subsequently to improve its viability. Four overlapping themes emerged from the data analyses, including hip hop-resistance to formal education; how hip hop culture informs pedagogical practice in hip hop-responsive classrooms; conceptions of knowledge and reality that shape how hip hoppers conduct scientific inquiry; and hip hop-based philosophies of effective teaching for hip hoppers as a marginalized cultural group. The findings indicate that there are unique connections between hip hop epistemology, sciencemindedness, and pedagogical practices in STEAM education. The revised theoretical framework clarified the nature of these connections, and supported claims from prior research that hip hop culture provides viable sites of

  4. Susceptibility of Pediococcus isolates to antimicrobial compounds in relation to hop-resistance and beer-spoilage

    Directory of Open Access Journals (Sweden)

    Ziola Barry

    2009-09-01

    Full Text Available Abstract Background Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol. Use of antimicrobial compounds (e.g., hop-compounds, Penicillin by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Results Lactic acid bacteria susceptibility test broth medium (LSM used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Conclusion Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed.

  5. Mic Power? Connections and the hip hop nation in Kampala, Uganda

    DEFF Research Database (Denmark)

    Schneidermann, Nanna

    2014-01-01

    Hip hop culture has been celebrated in the media and scholarship as a universal youth language, part of a global hip hop nation, and a type of counter-public. This article examines the everyday meanings and practices of hip hop among hip hop activists in Kampala, Uganda, specifically within...... the Batuuze rap group. Rather than portraying hip hop as a counter-public of the disempowered, I argue that the Batuuze engagement is based on what I call moral economy that enables the negotiation of connections in social and cultural networks towards what is considered a good life. Here, the hip hop nation...

  6. Hip Hop Dance Experience Linked to Sociocognitive Ability.

    Directory of Open Access Journals (Sweden)

    Justin W Bonny

    Full Text Available Expertise within gaming (e.g., chess, video games and kinesthetic (e.g., sports, classical dance activities has been found to be linked with specific cognitive skills. Some of these skills, working memory, mental rotation, problem solving, are linked to higher performance in science, technology, math, and engineering (STEM disciplines. In the present study, we examined whether experience in a different activity, hip hop dance, is also linked to cognitive abilities connected with STEM skills as well as social cognition ability. Dancers who varied in hip hop and other dance style experience were presented with a set of computerized tasks that assessed working memory capacity, mental rotation speed, problem solving efficiency, and theory of mind. We found that, when controlling for demographic factors and other dance style experience, those with greater hip hop dance experience were faster at mentally rotating images of hands at greater angle disparities and there was a trend for greater accuracy at identifying positive emotions displayed by cropped images of human faces. We suggest that hip hop dance, similar to other more technical activities such as video gameplay, tap some specific cognitive abilities that underlie STEM skills. Furthermore, we suggest that hip hop dance experience can be used to reach populations who may not otherwise be interested in other kinesthetic or gaming activities and potentially enhance select sociocognitive skills.

  7. Hip Hop Dance Experience Linked to Sociocognitive Ability.

    Science.gov (United States)

    Bonny, Justin W; Lindberg, Jenna C; Pacampara, Marc C

    2017-01-01

    Expertise within gaming (e.g., chess, video games) and kinesthetic (e.g., sports, classical dance) activities has been found to be linked with specific cognitive skills. Some of these skills, working memory, mental rotation, problem solving, are linked to higher performance in science, technology, math, and engineering (STEM) disciplines. In the present study, we examined whether experience in a different activity, hip hop dance, is also linked to cognitive abilities connected with STEM skills as well as social cognition ability. Dancers who varied in hip hop and other dance style experience were presented with a set of computerized tasks that assessed working memory capacity, mental rotation speed, problem solving efficiency, and theory of mind. We found that, when controlling for demographic factors and other dance style experience, those with greater hip hop dance experience were faster at mentally rotating images of hands at greater angle disparities and there was a trend for greater accuracy at identifying positive emotions displayed by cropped images of human faces. We suggest that hip hop dance, similar to other more technical activities such as video gameplay, tap some specific cognitive abilities that underlie STEM skills. Furthermore, we suggest that hip hop dance experience can be used to reach populations who may not otherwise be interested in other kinesthetic or gaming activities and potentially enhance select sociocognitive skills.

  8. The mechanical behavior and reliability prediction of the HTR graphite component at various temperature and neutron dose ranges

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xiang; Yu, Suyuan [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wang, Haitao, E-mail: wanght@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li, Chenfeng [Civil and Computational Engineering Centre, College of Engineering, Swansea University, Swansea SA2 8PP (United Kingdom)

    2014-09-15

    Highlights: • The mechanical behavior of graphite component in HTRs under high temperature and neutron irradiation conditions is simulated. • The computational process of mechanical analysis is introduced. • Deformation, stresses and failure probability of the graphite component are obtained and discussed. • Various temperature and neutron dose ranges are selected in order to investigate the effect of in-core conditions on the results. - Abstract: In a pebble-bed high temperature gas-cooled reactor (HTR), nuclear graphite serves as the main structural material of the side reflectors. The reactor core is made up of a large number of graphite bricks. In the normal operation case of the reactor, the maximum temperature of the helium coolant commonly reaches about 750 °C. After around 30 years’ full power operation, the peak value of in-core fast neutron cumulative dose reaches to 1 × 10{sup 22}n cm{sup −2} (EDN). Such high temperature and neutron irradiation strongly impact the behavior of graphite component, causing obvious deformation. The temperature and neutron dose are unevenly distributed inside a graphite brick, resulting in stress concentrations. The deformation and stress concentration can both greatly affect safety and reliability of the graphite component. In addition, most of the graphite properties (such as Young's modulus and coefficient of thermal expansion) change remarkably under high temperature and neutron irradiations. The irradiation-induced creep also plays a very important role during the whole process, and provides a significant impact on the stress accumulation. In order to simulate the behavior of graphite component under various in-core conditions, all of the above factors must be considered carefully. In this paper, the deformation, stress distribution and failure probability of a side graphite component are studied at various temperature points and neutron dose levels. 400 °C, 500 °C, 600 °C and 750 °C are selected

  9. Discrimination of different hop varieties using headspace gas chromatographic data

    Directory of Open Access Journals (Sweden)

    Jorge Katia

    2003-01-01

    Full Text Available Methods for characterization of hop varieties include analyses of bitter acids and essential oils, followed by comparison of the chemical composition, particularly chromatographic profiles. In the present work discrimination of different hop varieties was carried out based on their essential oil volatile composition, assessed by headspace gas chromatography, with subsequent statistical treatment of the data. Differences and similarities were determined in samples from USA, New Zealand and Europe, using correlation and cluster analysis. Aroma hops presented low levels of myrcene while bitter samples showed high levels of beta-caryophyllene, aloaromadendrene and also the sum of the marker ratios, independently of being in the form of pellets or extracts. Highly correlated samples with no significant differences have good possibility to substitute each other in the beer manufacture.

  10. Switched diversity strategies for dual-hop relaying systems

    KAUST Repository

    Gaaloul, Fakhreddine

    2011-04-29

    This paper investigates the effect of different switched diversity configurations on the implementation complexity and achieved performance of dual-hop amplify-and-forward (AF) relaying networks. A low-complexity model of the relay station is adopted, wherein single-input single-output antenna configuration is employed. Each of the transmitter and the receiver however employs multiple antennas to improve the overall link performance. Single-phase and two-phase based receive switching strategies are investigated assuming optimum first hop signal-to-noise ratio (SNR). Moreover, the simple scheme in which the switched diversity is applied independently over the two hops is studied using tight upper bounds. Thorough performance comparisons and switching thresholds optimization for the aforementioned strategies are presented. Simulation results are also provided to validate the mathematical development and to verify the numerical computations.

  11. Atom-by-Atom and Concerted Hopping of Adatom Pairs on an Open Metal Surface

    Energy Technology Data Exchange (ETDEWEB)

    Bogicevic, A.; Ovesson, S.; Lundqvist, B.I.; Jennison, D.R.

    1999-08-25

    Atom-by-atom and concerted hopping of ad-dimers on the open (100) surface of fcc metals are studied by means of density-functional calculations. The adatom interaction is relatively short-ranged, and beyond next-nearest neighbors ad-dimers are effectively dissociated. Diffusion takes place by a simple shearing process, favored because it maximizes adatom coordination at the transition state This holds for Al, Au, and Rh, and is likely a general result because geometrical arguments dominate over details of the electronic structure.

  12. Saccharomyces cerevisiae Red1 protein exhibits nonhomologous DNA end-joining activity and potentiates Hop1-promoted pairing of double-stranded DNA.

    Science.gov (United States)

    Kshirsagar, Rucha; Ghodke, Indrajeet; Muniyappa, K

    2017-08-18

    Elucidation of the function of synaptonemal complex (SC) in Saccharomyces cerevisiae has mainly focused on in vivo analysis of recombination-defective meiotic mutants. Consequently, significant gaps remain in the mechanistic understanding of the activities of various SC proteins and the functional relationships among them. S. cerevisiae Hop1 and Red1 are essential structural components of the SC axial/lateral elements. Previous studies have demonstrated that Hop1 is a structure-selective DNA-binding protein exhibiting high affinity for the Holliday junction and promoting DNA bridging, condensation, and pairing between double-stranded DNA molecules. However, the exact mode of action of Red1 remains unclear, although it is known to interact with Hop1 and to suppress the spore viability defects of hop1 mutant alleles. Here, we report the purification and functional characterization of the full-length Red1 protein. Our results revealed that Red1 forms a stable complex with Hop1 in vitro and provided quantitative insights into their physical interactions. Mechanistically, Red1 preferentially associated with the Holliday junction and 3-way junction rather than with single- or double-stranded DNA with overhangs. Although Hop1 and Red1 exhibited similar binding affinities toward several DNA substrates, the two proteins displayed some significant differences. Notably, Red1, by itself, lacked DNA-pairing ability; however, it potentiated Hop1-promoted intermolecular pairing between double-stranded DNA molecules. Moreover, Red1 exhibited nonhomologous DNA end-joining activity, thus revealing an unexpected role for Red1 in recombination-based DNA repair. Collectively, this study presents the first direct insights into Red1's mode of action and into the mechanism underlying its role in chromosome synapsis and recombination. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Lattice Gauge Quantum Simulation via State-Dependent Hopping

    DEFF Research Database (Denmark)

    Salami Dehkharghani, Amin

    2017-01-01

    We develop a quantum simulator architecture that is suitable for the simulation of U(1) Abelian gauge theories such as quantum electrodynamics. Our approach relies on the ability to control the hopping of a particle through a barrier by means of the internal quantum states of a neutral or charged...... impurity-particle sitting at the barrier. This scheme is highly experimentally feasible, as the correlated hopping does not require fine-tuning of the intra- and inter-species interactions. We investigate the applicability of the scheme in a double well potential, which is the basic building block...

  14. Information structure in Wichí: focus marker hop

    OpenAIRE

    Ekaterina Levina

    2013-01-01

    Abstract: The present paper provides an overview of the functions of the morphological focus marker hop in the grammar of Wichí, a Mataco-Mataguayan language spoken in the North of Argentina and the South of Bolivia. Basing the analysis on the corpus which I have compiled from the existing research which has been published on the language so far, we can conclude that the focus marker hop can but does not have to be used for the focusing of the subject, object, predicate, adverbial as well as ...

  15. Dielectric properties of the lithium-titanium ferrite ceramics in a wide frequency range

    Science.gov (United States)

    Surzhikov, A. P.; Gyngazov, S. A.; Lysenko, E. N.; Frangul'yan, T. S.; Malyshev, A. V.

    2015-06-01

    Electrophysical properties of the Li-Ti ferrite ceramics with the spinel structure (Li0.649Fe1.598Ti0.5Zn0.2Mn0.051O4) are studied in the frequency interval 0.5-2.5 GHz at temperatures ranging from room temperature to 530 K. The thermal emf of the ferrite ceramic samples is studied. It is demonstrated that the sample under study exhibits electron conduction. The calculated results are used to interpret the conduction mechanism using the hopping model.

  16. Starting with Style: Toward a Second Wave of Hip-Hop Education Research and Practice

    Science.gov (United States)

    Petchauer, Emery

    2015-01-01

    One fundamental breakthrough in the field of hip-hop education in recent years is the shift from understanding hip-hop solely as content to understanding hip-hop also as aesthetic form. In this article, I chart the roots of this shift across disciplines and focus on what it might mean for the future of hip-hop education, pedagogy, and research in…

  17. Suppression of Plant Immune Responses by the Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Effector Tyrosine Phosphatases HopAO1 and HopAO2

    Science.gov (United States)

    Castañeda-Ojeda, María Pilar; Moreno-Pérez, Alba; Ramos, Cayo; López-Solanilla, Emilia

    2017-01-01

    The effector repertoire of the olive pathogen P. savastanoi pv. savastanoi NCPPB 3335 includes two members of the HopAO effector family, one of the most diverse T3E families of the P. syringae complex. The study described here explores the phylogeny of these dissimilar members, HopAO1 and HopAO2, among the complex and reveals their activities as immune defense suppressors. Although HopAO1 is predominantly encoded by phylogroup 3 strains isolated from woody organs of woody hosts, both HopAO1 and HopAO2 are phylogenetically clustered according to the woody/herbaceous nature of their host of isolation, suggesting host specialization of the HopAO family across the P. syringae complex. HopAO1 and HopAO2 translocate into plant cells and show hrpL-dependent expression, which allows their classification as actively deployed type III effectors. Our data also show that HopAO1 and HopAO2 possess phosphatase activity, a hallmark of the members of this family. Both of them exert an inhibitory effect on early plant defense responses, such as ROS production and callose deposition, and are able to suppress ETI responses induced by the effectorless polymutant of P. syringae pv. tomato DC3000 (DC3000D28E) in Nicotiana. Moreover, we demonstrate that a ΔhopAO1 mutant of P. savastanoi NCPBB 3335 exhibits a reduced fitness and virulence in olive plants, which supports the relevance of this effector during the interaction of this strain with its host plants. This work contributes to the field with the first report regarding functional analysis of HopAO homologs encoded by P. syringae or P. savastanoi strains isolated from woody hosts. PMID:28529516

  18. Localization of networks with presence and distance constraints based on 1-hop and 2-hop mass–spring optimization

    Directory of Open Access Journals (Sweden)

    Gabriele Oliva

    2016-03-01

    Full Text Available In this paper we consider the localization of a sensor network where the nodes are heterogeneous, in that some of them are able to measure the distance from their neighbors, while some others are just able to detect their presence, and we provide a post-processing algorithm that can be used to improve an initial estimate for the location of the nodes, based on a mass–spring optimization approach, taking into account presence and distance information, as well as one-hop and two-hop information.

  19. Flipping the Misogynist Script: Gender, Agency, Hip Hop and Music Education

    Science.gov (United States)

    Tobias, Evan S.

    2014-01-01

    Excluding Hip Hop culture and rap music from music education misses opportunities for addressing key aspects of popular culture, society, and students' lives. This article addresses intersections of Hip Hop, gender, and music education to forward potential Hip Hop praxis. After tracing related scholarship, I discuss and problematize…

  20. Behind Beats and Rhymes: Working Class from a Hampton Roads Hip Hop Homeplace

    Science.gov (United States)

    Durham, Aisha S.

    2009-01-01

    The film documentary titled "Hip Hop: beyond beats and rhymes" captures ongoing conversations among scholars, cultural critics, and hip hop insiders about the state of African Americans by interrogating distinct expressive forms associated with hip hop culture. Durham draws from two scenes to describe her memories as the researched…

  1. "Deeper than Rap": Gifted Males and Their Relationship with Hip Hop Culture

    Science.gov (United States)

    Callahan, J. Sean; Grantham, Tarek C.

    2012-01-01

    One would be hard-pressed to deny the impact that hip hop is having on gifted students. More specifically, because hip hop is a creative and exciting male-dominated culture, gifted males gravitate to hip hop culture. From the perspective of two Black men from two different generations, this article was inspired by discussions about the role of hip…

  2. Beats, Rhymes, and Classroom Life: Hip-Hop Pedagogy and the Politics of Identity

    Science.gov (United States)

    Hill, Marc Lamont

    2009-01-01

    For over a decade, educators have looked to capitalize on the appeal of hip-hop culture, sampling its language, techniques, and styles as a way of reaching out to students. But beyond a fashionable hipness, what does hip-hop have to offer our schools? In this revelatory new book, Marc Lamont Hill shows how a serious engagement with hip-hop culture…

  3. Wish to Live: The Hip-Hop Feminism Pedagogy Reader. Educational Psychology. Volume 3

    Science.gov (United States)

    Brown, Ruth Nicole, Ed.; Kwakye, Chamara Jewel, Ed.

    2012-01-01

    "Wish To Live: The Hip-hop Feminism Pedagogy Reader" moves beyond the traditional understanding of the four elements of hip-hop culture--rapping, breakdancing, graffiti art, and deejaying--to articulate how hip-hop feminist scholarship can inform educational practices and spark, transform, encourage, and sustain local and global youth…

  4. Hind limb scaling of kangaroos and wallabies (superfamily Macropodoidea): implications for hopping performance, safety factor and elastic savings

    Science.gov (United States)

    McGowan, C P; Skinner, J; Biewener, A A

    2008-01-01

    The aim of this study was to examine hind limb scaling of the musculoskeletal system in the Macropodoidea, the superfamily containing wallabies and kangaroos, to re-examine the effect of size on the locomotor mechanics and physiology of marsupial hopping. Morphometric musculoskeletal analyses were conducted of 15 species and skeletal specimens of 21 species spanning a size range from 0.8 to 80 kg that included representatives of 12 of the 16 extant genera of macropodoids. We found that unlike other groups, macropodoids are able to match force demands associated with increasing body size primarily through a combination of positive allometry in muscle area and muscle moment arms. Isometric scaling of primary hind limb bones suggests, however, that larger species experience relatively greater bone stresses. Muscle to tendon area ratios of the ankle extensors scale with strong positive allometry, indicating that peak tendon stresses also increase with increasing body size but to a lesser degree than previously reported. Consistent with previous morphological and experimental studies, large macropodoids are therefore better suited for elastic strain energy recovery but operate at lower safety factors, which likely poses an upper limit to body size. Scaling patterns for extant macropodoids suggest that extinct giant kangaroos (∼250 kg) were likely limited in locomotor capacity. PMID:18086129

  5. Hind limb scaling of kangaroos and wallabies (superfamily Macropodoidea): implications for hopping performance, safety factor and elastic savings.

    Science.gov (United States)

    McGowan, C P; Skinner, J; Biewener, A A

    2008-02-01

    The aim of this study was to examine hind limb scaling of the musculoskeletal system in the Macropodoidea, the superfamily containing wallabies and kangaroos, to re-examine the effect of size on the locomotor mechanics and physiology of marsupial hopping. Morphometric musculoskeletal analyses were conducted of 15 species and skeletal specimens of 21 species spanning a size range from 0.8 to 80 kg that included representatives of 12 of the 16 extant genera of macropodoids. We found that unlike other groups, macropodoids are able to match force demands associated with increasing body size primarily through a combination of positive allometry in muscle area and muscle moment arms. Isometric scaling of primary hind limb bones suggests, however, that larger species experience relatively greater bone stresses. Muscle to tendon area ratios of the ankle extensors scale with strong positive allometry, indicating that peak tendon stresses also increase with increasing body size but to a lesser degree than previously reported. Consistent with previous morphological and experimental studies, large macropodoids are therefore better suited for elastic strain energy recovery but operate at lower safety factors, which likely poses an upper limit to body size. Scaling patterns for extant macropodoids suggest that extinct giant kangaroos (approximately 250 kg) were likely limited in locomotor capacity.

  6. Numerical simulation of the mechanical behavior of ultrafine- and coarse-grained Zr-Nb alloys over a wide range of strain rates

    Science.gov (United States)

    Serbenta, V. A.; Skripnyak, N. V.; Skripnyak, V. A.; Skripnyak, E. G.

    2017-12-01

    This paper presents the results on the development of theoretical methods of evaluation and prediction of mechanical properties of Zr-Nb alloys over a range of strain rates from 10-3 to 103 s-1. The mechanical behavior of coarse- and ultrafine-grained Zr-1Nb (E110) was investigated numerically. The ranges of strain rates and temperatures in which the mechanical behavior of Zr-1Nb alloy can be described using modified models of Johnson-Cook and Zerilli-Armstrong were defined. The results can be used in engineering analysis of designed technical systems for nuclear reactors.

  7. Influence of sputtering atmosphere on hopping conductance in granular nanocomposite (FeCoZr){sub x}(Al{sub 2}O{sub 3}){sub 1−x} films

    Energy Technology Data Exchange (ETDEWEB)

    Svito, I. [Belarusian State University, 220030 Minsk (Belarus); Fedotova, J.A. [National Center for Particles and High Energy Physics of BSU, 220040 Minsk (Belarus); Milosavljević, M. [VINČA Institute of Nuclear Sciences, Belgrade University, 11001 Belgrade (Serbia); Zhukowski, P. [Lublin University of Technology, 20-618 Lublin (Poland); Koltunowicz, T.N., E-mail: t.koltunowicz@pollub.pl [Lublin University of Technology, 20-618 Lublin (Poland); Saad, A. [Al Balqa Applied University, Physics Department, P.O. Box 4545, Amman 11953 (Jordan); Kierczynski, K. [Lublin University of Technology, 20-618 Lublin (Poland); Fedotov, A.K. [Belarusian State University, 220030 Minsk (Belarus)

    2014-12-05

    Highlights: • Nanocomposites deposited in oxygen-containing atmosphere (Ar + O{sub 2}). • Higher activation energies values for the hopping electronic transport. • Formation of FeCo-based oxide “shells” which separate FeCoZr nanoparticles. - Abstract: The present paper investigates conductivity σ for a wide temperature range of 2 K < T < 300 K in the nanocomposite (FeCoZr){sub x}(Al{sub 2}O{sub 3}){sub 1−x} films (1–6 μm thicknesses, 0.30 < x < 1.00) which were sputtered on glass–ceramic substrates from the compound target in vacuum chamber filled with Ar (set 1 films) or Ar + O{sub 2} gas mixture (set 2 films). TEM and HRTEM images revealed that granular films of set 1 containing nanosized crystalline metallic bcc α-FeCo-based nanoparticles embedded in the amorphous Al{sub 2}O{sub 3} matrix. In case of Ar + O atmosphere of deposited α-FeCo-based crystalline “cores” with stabilized sizes were covered with an amorphous FeCo-based oxide “shells”. The σ(T) dependences were found to be in agreement with this phase structure. They show transition of the set 1 films σ(T) curves with x from tunneling (hopping) behavior below the percolation threshold x < x{sub C} ≈ 0.46 to metallic one for x > x{sub C}. Moreover, as opposed to such behavior, for the set 2 films hopping mechanism of σ(T) was revealed far beyond x{sub C} due to the formation of semiconducting FeCo-based oxide “shells” separating electrically contacting FeCoZr cores.

  8. Investigación a ritmo de hip-hop

    Directory of Open Access Journals (Sweden)

    Melisa Rivière

    2013-09-01

    Full Text Available Soñando se resiste. Hip-hop; en la calle y al parque. Varios autores. Alcaldía Mayor de Bogotá, Secretaría de Cultura, Recreación y Deporte, Orquesta Filarmónica de Bogotá, Bogotá, 2010, 180 págs.

  9. Interference-based routing in multi-hop wireless infrastructures

    NARCIS (Netherlands)

    Heijenk, Geert; Liu, F.; Braun, Torsten; Carle, Georg; Koucheryavy, Yevgeni; Tsaoussidis, Vassilis

    In this paper, multi-hop wireless infrastructures are identified as a way to increase user data rates and/or capacity of wireless systems by means of a high base station density without high base station interconnection costs. For such a system, a new routing algorithm, named Balanced Interference

  10. Maroc-hop: music and youth identities in the Netherlands

    NARCIS (Netherlands)

    Gazzah, M.; Herrera, L.; Bayat, A.

    2010-01-01

    Two musical forms highly popular among youths of Moroccan origin in the Netherlands—Maroc-hop and Shaabi—permit youths to express specific and multiple identities in local contexts. Shaabi, a popular form of Moroccan folk music used to be found mainly in the private setting of family celebrations,

  11. Contribution of afferent feedback and descending drive to human hopping

    DEFF Research Database (Denmark)

    Zuur, Abraham T.; Lundbye-Jensen, Jesper; Leukel, Christian

    2010-01-01

    During hopping an early burst can be observed in the EMG from the soleus muscle starting about 45 ms after touch-down. It may be speculated that this early EMG burst is a stretch reflex response superimposed on activity from a supra-spinal origin. We hypothesised that if a stretch reflex indeed c...

  12. Potential African Substitutes for Hops in Tropical Beer Brewing

    African Journals Online (AJOL)

    1' Department of Food Science and Nutrition, E.N.S.A.I.. P. O. Box. 455, University ofNgaoundere, Cameroon. 2' Department of Food Technology, Faculty of Technology, University of Ibadan, Nigeria. "Corresponding author. Abstract. The potential ... Industry (Hough er dl., 1982, Grant,. 1977). Hops contribute to foam stability.

  13. Interference-based routing in multi-hop wireless infrastructures

    NARCIS (Netherlands)

    Heijenk, Geert; Liu, F.; Braun, T.; Carle, G.; Koucheryavy, Y.; Tsaoussidis, V.

    In this paper, multi-hop wireless infrastructures are identified as a way to increase user data rates and/or capacity of wireless systems by means of a high base station density without high base station interconnection costs. For such a system, a new routing algorithm, named balanced interference

  14. Hopping in a supercooled binary Lennard-Jones liquid

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    1998-01-01

    A binary Lennard–Jones liquid has been investigated by molecular dynamics at equilibrium supercooled conditions. At the lowest temperature investigated, hopping is present in the system as indicated by a secondary peak in 4r2Gs(r,t), where Gs(r,t) is the van Hove self correlation function...

  15. Young Children Manifest Spiritualities in Their Hip-Hop Writing

    Science.gov (United States)

    Norton, Nadjwa E. L.

    2014-01-01

    In this article, the author combines multicultural feminist critical theories with the voices of Black and Latina/Latino young spiritual children to extend culturally responsive teaching. The author illuminates how children use their hip-hop writing to construct themselves as people who communicate with God, choose spiritual content for their…

  16. Examining Hip-Hop as Culturally Relevant Pedagogy

    Science.gov (United States)

    Kim, Jung; Pulido, Isaura

    2015-01-01

    Culturally relevant pedagogy is a framework that conceptualizes the process of student learning as contingent upon educators' deep understanding of students' cultural backgrounds to co-construct knowledge and develop academic skills. Concurrently, there are a growing number of studies that explore hip-hop as a culturally relevant curriculum for…

  17. Morphological and control criteria for self-stable underwater hopping.

    Science.gov (United States)

    Calisti, Marcello; Laschi, Cecilia

    2017-10-04

    This paper presents the self-stabilisation features of a hopping gait during underwater legged locomotion. We used a bio-inspired fundamental model of this gait, the underwater spring-loaded inverted pendulum model, to numerically derive quantitative (dimension of the basin of attraction, Floquet multipliers, mean horizontal speed) and qualitative (shape of the basin) features which characterise the self-stability of the system. Furthermore, we compared the results obtained with a terrestrial self-stable running model (i.e. the spring-loaded inverted pendulum with swing-leg retraction) to highlight the role of water-related components in relation to dynamic legged locomotion. The analysis revealed fundamental morphological and actuation parameters that could be used to design self-stabilising underwater hopping machines, as well as elucidating their role with respect to stability and speed. Underwater hopping is a simple and reliable locomotion, as it does not require complex control feedback to reject significant disturbances. Thanks to its high self-stabilising property, underwater hopping appears to be a reliable alternative locomotion for underwater robots. © 2017 IOP Publishing Ltd.

  18. Exact results on the steady state of a hopping model

    Science.gov (United States)

    Zhang, M. Q.

    1987-03-01

    A hopping model described by Katz, Lebowitz, and Spohn [J. Stat. Phys. 34, 497 (1983)] and by Valles and Marro [J. Stat. Phys. 43, 441 (1986)] is studied analytically for small lattice systems. The dependence of the nonequilibrium steady state on various parameters and transition rate functions is obtained exactly. The results are compared with simulations on large systems.

  19. Surface hopping modeling of two-dimensional spectra

    NARCIS (Netherlands)

    Tempelaar, Roel; Vegte, Cornelis P. van der; Knoester, Jasper; Jansen, Thomas L.C.

    2013-01-01

    Recently, two-dimensional (2D) electronic spectroscopy has become an important tool to unravel the excited state properties of complex molecular assemblies, such as biological light harvesting systems. In this work, we propose a method for simulating 2D electronic spectra based on a surface hopping

  20. Multiple-hopping trajectories near a rotating asteroid

    Science.gov (United States)

    Shen, Hong-Xin; Zhang, Tian-Jiao; Li, Zhao; Li, Heng-Nian

    2017-03-01

    We present a study of the transfer orbits connecting landing points of irregular-shaped asteroids. The landing points do not touch the surface of the asteroids and are chosen several meters above the surface. The ant colony optimization technique is used to calculate the multiple-hopping trajectories near an arbitrary irregular asteroid. This new method has three steps which are as follows: (1) the search of the maximal clique of candidate target landing points; (2) leg optimization connecting all landing point pairs; and (3) the hopping sequence optimization. In particular this method is applied to asteroids 433 Eros and 216 Kleopatra. We impose a critical constraint on the target landing points to allow for extensive exploration of the asteroid: the relative distance between all the arrived target positions should be larger than a minimum allowed value. Ant colony optimization is applied to find the set and sequence of targets, and the differential evolution algorithm is used to solve for the hopping orbits. The minimum-velocity increment tours of hopping trajectories connecting all the landing positions are obtained by ant colony optimization. The results from different size asteroids indicate that the cost of the minimum velocity-increment tour depends on the size of the asteroids.

  1. Chiral Topological Superconductors Enhanced by Long-Range Interactions

    Science.gov (United States)

    Viyuela, Oscar; Fu, Liang; Martin-Delgado, Miguel Angel

    2018-01-01

    We study the phase diagram and edge states of a two-dimensional p -wave superconductor with long-range hopping and pairing amplitudes. New topological phases and quasiparticles different from the usual short-range model are obtained. When both hopping and pairing terms decay with the same exponent, one of the topological chiral phases with propagating Majorana edge states gets significantly enhanced by long-range couplings. On the other hand, when the long-range pairing amplitude decays more slowly than the hopping, we discover new topological phases where propagating Majorana fermions at each edge pair nonlocally and become gapped even in the thermodynamic limit. Remarkably, these nonlocal edge states are still robust, remain separated from the bulk, and are localized at both edges at the same time. The inclusion of long-range effects is potentially applicable to recent experiments with magnetic impurities and islands in 2D superconductors.

  2. Analysis of mode-hopping effect in Fabry–Pérot multiple-quantum well laser diodes via low frequency noise investigation

    DEFF Research Database (Denmark)

    Pralgauskaitė, Sandra; Palenskis, Vilius; Matukas, Jonas

    2013-01-01

    Comprehensive investigation of noise characteristics and radiation spectrum with special attention to the mode-hopping effect of Fabry–Pérot (FP) multiple quantum well laser diodes (LDs) have been carried out: laser radiation spectra, optical and electrical fluctuations and cross-correlation factor...... fluctuations are observed. Characteristic time of physical processes that take part in LD structure during mode-hopping is ranged from microseconds to milliseconds. These processes are caused by the carrier generation and recombination in the centers formed by the defects in barrier layer (in the active region)....

  3. Multi-Hop-Enabled Energy-Efficient MAC Protocol for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Khaja Shazzad

    2015-09-01

    Full Text Available In multi-hop underwater acoustic sensor networks (UWASNs, packet collisions due to hidden and local nodes adversely affect throughput, energy efficiency and end-to-end delay. Existing medium access control (MAC protocols try to solve the problem by utilizing a single-phase contention resolution mechanism, which causes a large number of control packet exchanges and energy overhead. In this paper, we introduce a MAC protocol that splits this single-phase contention resolution mechanism into two phases to provide efficient multi-hop networking. In the first phase, local nodes are eliminated from the contention, and in the later phase, the adverse effects of hidden nodes are mitigated. This two-phased contention resolution provides higher energy efficiency, better throughput and shorter end-to-end delay, and it also enables adaptability for different network architectures. A probabilistic model of the proposed protocol is also developed to analyse the performance. The proposed protocol has been evaluated through quantitative analysis and simulation. Results obtained through quantitative analysis and simulation reveal that the proposed protocol achieves significantly better energy efficiency, higher and more stable throughput and lower end-to-end delay compared to existing protocols, namely T-Lohi and slotted floor acquisition multiple access (S-FAMA.

  4. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  5. ANOMALOUS CO{sub 2} ICE TOWARD HOPS-68: A TRACER OF PROTOSTELLAR FEEDBACK

    Energy Technology Data Exchange (ETDEWEB)

    Poteet, Charles A.; Megeath, S. Thomas; Bjorkman, Jon E. [Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Pontoppidan, Klaus M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Watson, Dan M.; Sheehan, Patrick D. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Isokoski, Karoliina; Linnartz, Harold, E-mail: charles.poteet@gmail.com [Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2013-04-01

    We report the detection of a unique CO{sub 2} ice band toward the deeply embedded, low-mass protostar HOPS-68. Our spectrum, obtained with the Infrared Spectrograph on board the Spitzer Space Telescope, reveals a 15.2 {mu}m CO{sub 2} ice bending mode profile that cannot be modeled with the same ice structure typically found toward other protostars. We develop a modified CO{sub 2} ice profile decomposition, including the addition of new high-quality laboratory spectra of pure, crystalline CO{sub 2} ice. Using this model, we find that 87%-92% of the CO{sub 2} is sequestered as spherical, CO{sub 2}-rich mantles, while typical interstellar ices show evidence of irregularly shaped, hydrogen-rich mantles. We propose that (1) the nearly complete absence of unprocessed ices along the line of sight is due to the flattened envelope structure of HOPS-68, which lacks cold absorbing material in its outer envelope, and possesses an extreme concentration of material within its inner (10 AU) envelope region and (2) an energetic event led to the evaporation of inner envelope ices, followed by cooling and re-condensation, explaining the sequestration of spherical, CO{sub 2} ice mantles in a hydrogen-poor mixture. The mechanism responsible for the sublimation could be either a transient accretion event or shocks in the interaction region between the protostellar outflow and envelope. The proposed scenario is consistent with the rarity of the observed CO{sub 2} ice profile, the formation of nearly pure CO{sub 2} ice, and the production of spherical ice mantles. HOPS-68 may therefore provide a unique window into the protostellar feedback process, as outflows and heating shape the physical and chemical structure of protostellar envelopes and molecular clouds.

  6. Hop pellets as an interesting source of antioxidant active compounds

    Directory of Open Access Journals (Sweden)

    Andrea Holubková

    2013-02-01

    Full Text Available Hop is a plant used by humankind for thousands of years. This plant is one of the main and indispensable raw materials for the beer production. It is used for various dishes preparation in the cuisine. Hop is also used to inhibit bacterial contamination. The hop extracts are used for its sedative, antiseptic and antioxidant properties in medicine, as a part of many phytopharmaceuticals. The present paper have focused on the extraction of polyphenolic compounds from 4 samples of hop pellets varieties of Aurora, Saaz, Lublin and Saphir, on the analyzing of bioactive substances (polyphenolics and flavonoids in prepared extracts and on the determination of antioxidant activity.  The highest content of polyphenolic substances was determined in the sample Lublin (153.06 mg gallic acid (GAE/g and Saaz (151.87 mg GAE/g. The amount of flavonoids in the samples  was descending order Saaz > Saphir > Aurora > Lublin. Hops, as plant, is known by high content of antioxidant active substances. Antioxidant activity was determined using three independent spectrofotometric methods, radical scavenging assays using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS and 1,1-diphenyl-2-picrylhydrazyl (DPPH radical and ferric reducing antioxidant power (FRAP. The sample Aurora showed the highest ability to scavenge of ABTS radical cation. Antioxidant activity continued to decline in a row Saphir> Lublin> Saaz. The same trend was also observed by using the FRAP assay. The most effective DPPH radical scavengering activity had the sample Saaz a Saphir (p>0.05.doi:10.5219/270 Normal 0 21 false false false SK X-NONE X-NONE

  7. Charge Carrier Hopping Dynamics in Homogeneously Broadened PbS Quantum Dot Solids.

    Science.gov (United States)

    Gilmore, Rachel H; Lee, Elizabeth M Y; Weidman, Mark C; Willard, Adam P; Tisdale, William A

    2017-02-08

    Energetic disorder in quantum dot solids adversely impacts charge carrier transport in quantum dot solar cells and electronic devices. Here, we use ultrafast transient absorption spectroscopy to show that homogeneously broadened PbS quantum dot arrays (σhom(2):σinh(2) > 19:1, σinh/kBT quantum dot batches are sufficiently monodisperse (δ ≲ 3.3%). The homogeneous line width is found to be an inverse function of quantum dot size, monotonically increasing from ∼25 meV for the largest quantum dots (5.8 nm diameter/0.92 eV energy) to ∼55 meV for the smallest (4.1 nm/1.3 eV energy). Furthermore, we show that intrinsic charge carrier hopping rates are faster for smaller quantum dots. This finding is the opposite of the mobility trend commonly observed in device measurements but is consistent with theoretical predictions. Fitting our data to a kinetic Monte Carlo model, we extract charge carrier hopping times ranging from 80 ps for the smallest quantum dots to over 1 ns for the largest, with the same ethanethiol ligand treatment. Additionally, we make the surprising observation that, in slightly polydisperse (δ ≲ 4%) quantum dot solids, structural disorder has a greater impact than energetic disorder in inhibiting charge carrier transport. These findings emphasize how small improvements in batch size dispersity can have a dramatic impact on intrinsic charge carrier hopping behavior and will stimulate further improvements in quantum dot device performance.

  8. The content of vitamine E in hop cones of the Saaz variety

    Directory of Open Access Journals (Sweden)

    Helena Pluháčková

    2013-01-01

    Full Text Available The activity of vitamin E, total content of tocols and the content of individual isomers: α-tocopherols, β-tocopherols, γ-tocopherols and δ-tocopherols was monitored in samples of hop cones of the world-important Saaz variety. Hop cone samples originated from hop-breeding area Tršice, Czech Republic. The method used for the determination of vitamin E in barley was modified and used for this quantitative analysis. The results indicate that monitored characteristics are influenced by the year of harvest (2010 or 2011 but also by the age of hop-gardens (hop bucks. High values of vitamin E activity (up to 67.79 mg.kg−1 and total content of tocols (up to 76.31 mg.kg−1 in hop cones are worth further attention from the viewpoint of alternative use of hops.

  9. Information structure in Wichí: focus marker hop

    Directory of Open Access Journals (Sweden)

    Ekaterina Levina

    2013-12-01

    Full Text Available Abstract: The present paper provides an overview of the functions of the morphological focus marker hop in the grammar of Wichí, a Mataco-Mataguayan language spoken in the North of Argentina and the South of Bolivia. Basing the analysis on the corpus which I have compiled from the existing research which has been published on the language so far, we can conclude that the focus marker hop can but does not have to be used for the focusing of the subject, object, predicate, adverbial as well as on entire dependent clauses in the language. The focus marker hop can express both the informational focus as well as the contrastive focus. In the case of predicate focusing the verum-focus can also be marked and the focus marker can scope over the complex predicate. Key words: Wichí; Languages of America; Information structure; Focus marker.  Resumo: O presente artigo fornece uma visão geral das funções do marcador morfológico hop na gramática de Wichí, uma linguagem Mataco-Mataguayan falada no norte da Argentina e no sul da Bolívia. Com base na análise do corpus que compilamos a partir das pesquisas existentes e publicadas sobre a língua até agora, podemos concluir que o marcador de foco hop pode, mas não tem que, necessariamente, ser usado para o foco no sujeito, objeto, predicado, advérbio, bem como nas cláusulas inteiramente dependentes na língua. O marcador de foco hop pode expressar tanto o foco informacional quanto o foco contrastante. No caso do predicado com foco no verum-foco, também pode ser marcado e o marcador de foco sobre o predicado complexo pode se estender. Palavras-chave: Wichí; idiomas da América; estrutura de informação; marcador de foco.  Resumen: El articulo presentado ofrece una descripción general de las funciones del marcador morfológico de foco hop en la gramática de la lengua Wichí, hablada en el Norte de Argentina y el Sur de Bolivia. El presente análisis hecho a base del corpus formado de

  10. Hip-Hop Guayaquil: culturas viajeras e identidades locales

    Directory of Open Access Journals (Sweden)

    1999-01-01

    Full Text Available HIP-HOP GUAYAQUIL: CULTURES ITINÉRANTES ET IDENTITES LOCALES. Le hip-hop est un style de musique contemporaine caractérisé par une orchestration d’œuvres lyriques rapées, la superposition de morceaux de musique enregistrés dans le passé par différents artistes, et une instrumentation électronique, tout cela sur des rythmes de basse réguliers et constants. Le hip-hop, musique accompagnée de ses propres danses et de sa mode, est le produit du déplacement et de la transformation d’une variété d’idéologies politiques de la communauté noire qui se constituent à partir de relations qui se modifient entre elles, et en relation avec les cultures dominantes contre lesquelles elles luttent quotidiennement. À l’origine, le hip-hop est lié à des mouvements d’identité de jeunes noirs. Dans cet article, il est intéressant d’étudier le rôle du hip-hop dans la formulation d’une identité entre jeunes métisses et noirs des secteurs populaires de Guayaquil. Cet exemple illustre la nécessité d’inclure dans l’analyse les dimensions politiques des processus de traduction du global au niveau local. El hip-hop es un género de música contemporánea caracterizado por la orquestación de líricas que son rapeadas, superposición de fragmentos de música grabada en el pasado por diferentes artistas, e instrumentación electrónica, todo ello sobre ritmos de bajo regulares y constantes. Como un tipo de música acompañado por sus propias formas de danza y moda, el hip-hop es producto del viaje y la transformación de una variedad de ideologías políticas de la comunidad negra que se constituyen a sí mismas en relaciones cambiantes entre sí y en relación a las culturas dominantes contra las cuales luchan cotidianamente. El hip-hop está ligado, en su contexto originario, a políticas de identidad defendidas por jóvenes negros. Lo que interesa explorar en este artículo es el papel del hip-hop en la formulación de una identidad

  11. Respiratory disease associated with occupational inhalation to hop (Humulus lupulus) during harvest and processing.

    Science.gov (United States)

    Reeb-Whitaker, Carolyn K; Bonauto, David K

    2014-11-01

    There is little published evidence for occupational respiratory disease caused by hop dust inhalation. In the United States, hops are commercially produced in the Pacific Northwest region. To describe occupational respiratory disease in hop workers. Washington State workers' compensation claims filed by hop workers for respiratory disease were systematically identified and reviewed. Incidence rates of respiratory disease in hop workers were compared with rates in field vegetable crop farm workers. Fifty-seven cases of respiratory disease associated with hop dust inhalation were reported from 1995 to 2011. Most cases (61%) were diagnosed by the attending health care practitioner as having work-related asthma. Seven percent of cases were diagnosed as chronic obstructive pulmonary disease, and the remaining cases were diagnosed as allergic respiratory disorders (eg, allergic rhinitis) or asthma-associated symptoms (eg, dyspnea). Cases were associated with hop harvesting, secondary hop processing, and indirect exposure. The incidence rate of respiratory disease in hop workers was 15 cases per 10,000 full-time workers, which was 30 times greater than the incidence rate for field vegetable crop workers. A strong temporal association between hop dust exposure and respiratory symptoms and a clear association between an increase in hop dust concentrations and the clinical onset of symptoms were apparent in 3 cases. Occupational exposure to hop dust is associated with respiratory disease. Respiratory disease rates were higher in hop workers than in a comparison group of agricultural workers. Additional research is needed before hop dust can be confirmed as a causative agent for occupational asthma. Copyright © 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  12. Site exploration for rock-mechanics field tests in the Grouse Canyon Member, Belted Range Tuff, U12g Tunnel Complex, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Langkopf, B.S.; Eshom, E.

    1982-02-01

    This report describes site exploration work completed in support of planned rock-mechanics field tests in the Grouse Canyon Member of the Belted Range Ruff at Nevada Test Site`s, G-Tunnel. As part of this work, the Rock Mechanics Drift (RMD) and the Rock Mass Property Alcove (RMPA) were mined and three coreholes drilled. The results of mapping and corehole logging are displayed, described, and analyzed.

  13. Correlation between hip function and knee kinematics evaluated by three-dimensional motion analysis during lateral and medial side-hopping.

    Science.gov (United States)

    Itoh, Hiromitsu; Takiguchi, Kohei; Shibata, Yohei; Okubo, Satoshi; Yoshiya, Shinichi; Kuroda, Ryosuke

    2016-09-01

    [Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated. Subsequently, the relationship between knee motion and the clinical parameters of the hip was analyzed. [Results] In the lateral touchdown phase, the knee was positioned in an abducted and externally rotated position, and increasing abduction moment was applied to the knee. An analysis of the interaction between knee motion and hip function showed that range of motion for hip internal rotation was significantly correlated with external rotation angle and external rotation/abduction moments of the knee during the lateral touchdown phase. [Conclusion] Range of motion for hip internal rotation should be taken into consideration for identifying the biomechanical characteristics in the side hop test results.

  14. Using Quantum Mechanics to Facilitate the Introduction of a Broad Range of Chemical Concepts to First-Year Undergraduate Students

    Science.gov (United States)

    deSouza, Romualdo T.; Iyengar, Srinivasan S.

    2013-01-01

    A first-year undergraduate course that introduces students to chemistry through a conceptually detailed description of quantum mechanics is outlined. Quantization as arising from the confinement of a particle is presented and these ideas are used to introduce the reasons behind resonance, molecular orbital theory, degeneracy of electronic states,…

  15. Fast frequency hopping codes applied to SAC optical CDMA network

    Science.gov (United States)

    Tseng, Shin-Pin

    2015-06-01

    This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

  16. Mixed quantum-classical equilibrium in global flux surface hopping.

    Science.gov (United States)

    Sifain, Andrew E; Wang, Linjun; Prezhdo, Oleg V

    2015-06-14

    Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors.

  17. Mixed quantum-classical equilibrium in global flux surface hopping

    Energy Technology Data Exchange (ETDEWEB)

    Sifain, Andrew E. [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0485 (United States); Wang, Linjun; Prezhdo, Oleg V. [Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062 (United States)

    2015-06-14

    Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors.

  18. O CIRCUITO HIP HOP NA REGIÃO DE CAMPINAS

    Directory of Open Access Journals (Sweden)

    Cristiano Nunes Alves

    2013-01-01

    Full Text Available This paper examines the thickness of the circuit hip hop in the region of Campinas and it’s a part of an inventory made in fifteen cities of the region, between 2003 and 2005. The circuit hip hop growing in Campinas since the decade of 1980, and has been expanding in the context of urbanization and metropolis. We noticed some residual cultural component in places involves, among others, the alternative production involved by a technically and territorial division of labor spurred by circuits upside of information. The culture of the streets and these circuits, survive to the urban division and fragmentation. It is, therefore, a study of the region of Campinas as a place that houses technical, informational and communicational densities. We analyzed geographical conditions of contemporary life in this region, inquiring about the communication and the informational components in the use of the territory.

  19. Cooperative MIMO technology in multiple hops wireless sensor networks

    Science.gov (United States)

    Yuan, Lina; Chen, Huajun; Gong, Jing

    2017-03-01

    The limited lifetime is one of the important factors restricted wireless sensor networks (WSNs), when possible, wireless nodes often operate with small batteries, while battery replacement is a very difficult and expensive. So the nodes must work long hours in the case of no battery replacement. Therefore, in WSNs, minimizing energy consumption is an important design consideration, at the same time, the transmission strategies of energy efficiency must be used for data forwarding. This paper, using cooperative multiple input multiple output(MIMO) technology combined with multiple hops technology, has put forward a new transmission model, i.e., the MIMO-MISO(multi-input multi-output)/MIMO-MIMO model. Simulation results demonstrate the proposed MIMO-MISO/MIMO-MIMO to minimize energy consumption of each node every node for multi-hop WSNs, to save a great deal of energy for a larger transmission distance, which makes the life of the entire network be extended.

  20. Contract Law and the self-enforcing range of contracts in agriculture. : Private institutions and multilateral reputation mechanisms

    OpenAIRE

    Mazé, Armelle

    2005-01-01

    The enforcement of contracts is necessary for efficient exchange in economic activities. The predominance in agriculture of informal contracts leads in many countries to the implementation of specific legal rules for contract law. This article emphasises the complementarities between public and private ordering when contracts are informal. We analyse the role of private contract-enforcement institution (CEI) as a support for multilateral reputation mechanisms. Our case study is focusing on in...

  1. Development of a Lidar System Based on an Infrared RangeFinder Sensor and SlipRing Mechanism

    OpenAIRE

    Bayar, Gokhan; Uludag, Alparslan

    2016-01-01

    Abstract-Lidar systems are one of the most important sensor infrastructures in autonomous vehicles and mobile robots. They are used for achieving indoor and outdoor mapping purposes. In the scope of this study, a new perspective to develop a lidar system is proposed. The system developed is constructed based on a low-cost infrared rangefinder sensor, low-cost slipring mechanism designed and manufactured, dc motor and microprocessor. The rangefinder sensor is mounted to a head-structure actuat...

  2. Mechanical performance of hydrogel contact lenses with a range of power under parallel plate compression and central load.

    Science.gov (United States)

    Robitaille, Michael; Shi, Jiayi; McBride, Shannon; Wan, Kai-Tak

    2013-06-01

    When a contact lens is compressed between two parallel plates (PPC) or under a central load (CLC), the constitutive relation depends not only on the mechanical properties such as elastic modulus, E, of the hydrogel materials, but also the lens power, d, or thickness variation, h(ϕ0), along the meridional direction ϕ0. Hyperopic lenses (d>0) are thicker at the apex along the optical axis and thin out gradually along the meridian, while myopic lenses (d<0) are thinnest at the apex. Mechanical deformation is quantified by the inter-relationship between applied force, F, vertical displacement of the external load, w0, contact or dimple radius, a, and the deformed profile, w(r). Force responses show that lenses with positive d are apparently stiffer in the initial loading but become more compliant as load increases. Conversely, lenses with negative d are more deformable initially and becomes gradually more resistant to loading. This is consistent with the theoretical shell model using the same E. The mechanical behavior has significant impacts in defining the degree of comfort of contact lenses as well as the lens adhesion to the corneal epithelium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Effects of Powdery Mildew Fungicide Programs on Twospotted Spider Mite (Acari: Tetranychidae), Hop Aphid (Homoptera: Aphididae), and Their Natural Enemies in Hop Yards

    Science.gov (United States)

    Twospotted spider mite, Tetranychus urticae Koch (Acari:Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Homoptera:Aphidiae), are the most important arthropod pests of hop (Humulus lupulus L.) in the Northern Hemisphere. A potential barrier for greater adoption of conservation biological c...

  4. Hip-Hop(e): The Cultural Practice and Critical Pedagogy of International Hip-Hop. Adolescent Cultures, School, and Society. Volume 56

    Science.gov (United States)

    Porfilio, Brad J., Ed.; Viola, Michael J., Ed.

    2012-01-01

    Illuminating hip-hop as an important cultural practice and a global social movement, this collaborative project highlights the emancipatory messages and cultural work generated by the organic intellectuals of global hip-hop. Contributors describe the social realities--globalization, migration, poverty, criminalization, and racism--youth are…

  5. HipHop Scholastics: Effective Teacher Professional Learning

    OpenAIRE

    Garcia, Itoco

    2016-01-01

    AbstractHipHop Scholastics: Effective Teacher Professional LearningbyItoco GarcíaDoctor of EducationUniversity of California, BerkeleyProfessor P. David Pearson, ChairMeeting the needs of culturally and linguistically diverse students in order to improve their academic engagement and achievement is a central challenge to American education. A Critical Race analysis and synthesis of academic research on teacher professional learning, Culturally Relevant Pedagogy (CRP), and the mismatch between...

  6. Reconstruction of Frequency Hopping Signals From Multi-Coset Samples

    OpenAIRE

    Lim, Chia Wei; Wakin, Michael B.

    2016-01-01

    Multi-Coset (MC) sampling is a well established, practically feasible scheme for sampling multiband analog signals below the Nyquist rate. MC sampling has gained renewed interest in the Compressive Sensing (CS) community, due partly to the fact that in the frequency domain, MC sampling bears a strong resemblance to other sub-Nyquist CS acquisition protocols. In this paper, we consider MC sampling of analog frequency hopping signals, which can be viewed as multiband signals with changing band ...

  7. Opportunistic Access in Frequency Hopping Cognitive Radio Networks

    Science.gov (United States)

    2014-03-27

    frequency hopping radio to mitigate the interference caused by other transmitters in a contentious environment such as the unlicensed 2.4 GHz region...Avionics Circle WPAFB, OH 45433 vasu.chakravarthy@us.af.mil 937- 528 -8269 AFRL/RYWE 12. DISTRIBUTION / AVAILABILITY STATEMENT DISTRIBUTION STATEMENT A...unlicensed 2.4 GHz region. Additionally, this work demonstrates how dynamic spectrum access techniques can be used not only to prevent interfering with

  8. Nanoscale live cell imaging using hopping probe ion conductance microscopy

    Science.gov (United States)

    Novak, Pavel; Li, Chao; Shevchuk, Andrew I.; Stepanyan, Ruben; Caldwell, Matthew; Hughes, Simon; Smart, Trevor G.; Gorelik, Julia; Ostanin, Victor P.; Lab, Max J.; Moss, Guy W. J.; Frolenkov, Gregory I.; Klenerman, David; Korchev, Yuri E.

    2009-01-01

    We describe a major advance in scanning ion conductance microscopy: a new hopping mode that allows non-contact imaging of the complex surfaces of live cells with resolution better than 20 nm. The effectiveness of this novel technique was demonstrated by imaging networks of cultured rat hippocampal neurons and mechanosensory stereocilia of mouse cochlear hair cells. The technique allows studying nanoscale phenomena on the surface of live cells under physiological conditions. PMID:19252505

  9. Potential macro-detritivore range expansion into the subarctic stimulates litter decomposition: a new positive feedback mechanism to climate change?

    OpenAIRE

    Geffen, van, LCMM; Berg, M.P.; Aerts, R.

    2011-01-01

    As a result of low decomposition rates, high-latitude ecosystems store large amounts of carbon. Litter decomposition in these ecosystems is constrained by harsh abiotic conditions, but also by the absence of macro-detritivores. We have studied the potential effects of their climate change-driven northward range expansion on the decomposition of two contrasting subarctic litter types. Litter of Alnus incana and Betula pubescens was incubated in microcosms together with monocultures and all pos...

  10. Hip-Hop Development™ Bridging the Generational Divide for Youth Development

    Directory of Open Access Journals (Sweden)

    P. Thandi Hicks Harper

    2007-09-01

    Full Text Available Hip-Hop culture in the lives of youth can not be ignored. This research is based on the premise that youth workers who expect ongoing successes must increase their Hip-Hop culture competence. The study examined the knowledge of and attitude towards Hip-Hop by educators who participated in a Hip-Hop 101 workshop. Their perceptions relevant to the importance of Hip-Hop awareness and application for positively influencing youth behaviors were also explored. Results revealed that workshop participants significantly increased their Hip-Hop knowledge. They also demonstrated significantly more favorable attitudes toward Hip-Hop and its use for youth development. Findings suggest that the workshop promoted an environment conducive to bridging the generation gap between youth who embrace Hip-Hop, and educators who have a less favorable view. This research provides insight into Hip-Hop Developmenttm as a core component for establishing the kinds of youth-adult partnerships necessary for today’s Hip-Hop generation’s self-growth, skill enhancement, and leadership development.

  11. Hsp70/Hsp90 organising protein (hop): beyond interactions with chaperones and prion proteins.

    Science.gov (United States)

    Baindur-Hudson, Swati; Edkins, Adrienne L; Blatch, Gregory L

    2015-01-01

    The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrP(C). The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrP(C). While Hop has been shown to have various cellular functions, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseases states.

  12. Comparison of the most odor-active compounds in fresh and dried hop cones (Humulus lupulus L. variety spalter select) based on GC-olfactometry and odor dilution techniques.

    Science.gov (United States)

    Steinhaus, M; Schieberle, P

    2000-05-01

    Application of aroma extract dilution analysis on the volatiles obtained from dried cones of Spalter Select hops grown in the German hop-growing area of Hallertau revealed 23 odorants in the flavor dilution (FD) factor range of 16-4096, 20 of which could be identified. On the basis of high FD factors, trans-4, 5-epoxy-(E)-2-decenal, linalool, and myrcene were identified as the most potent odorants, followed by ethyl 2-methylpropanoate, methyl 2-methylbutanoate, (Z)-1,5-octadien-3-one, nonanal, (E,Z)-1,3, 5-undecatriene, 1,3(E),5(Z),9-undecatetraene, propyl 2-methylbutanoate, 4-ethenyl-2-methoxyphenol, and 1-octen-3-one. Ten of the high-impact hop aroma compounds had previously not been identified as hop constituents and, in particular, 1,3(E),5(Z), 9-undecatetraene has not yet been reported as a food odorant. In an extract obtained from fresh hops, in addition to the odorants found in dry hops, (Z)-3-hexenal was characterized as a further key odorant rendering an additional green aroma note to the fresh material.

  13. Duplex Schemes in Multiple Antenna Two-Hop Relaying

    Directory of Open Access Journals (Sweden)

    Anja Klein

    2008-04-01

    Full Text Available A novel scheme for two-hop relaying defined as space division duplex (SDD relaying is proposed. In SDD relaying, multiple antenna beamforming techniques are applied at the intermediate relay station (RS in order to separate downlink and uplink signals of a bi-directional two-hop communication between two nodes, namely, S1 and S2. For conventional amplify-and-forward two-hop relaying, there appears a loss in spectral efficiency due to the fact that the RS cannot receive and transmit simultaneously on the same channel resource. In SDD relaying, this loss in spectral efficiency is circumvented by giving up the strict separation of downlink and uplink signals by either time division duplex or frequency division duplex. Two novel concepts for the derivation of the linear beamforming filters at the RS are proposed; they can be designed either by a three-step or a one-step concept. In SDD relaying, receive signals at S1 are interfered by transmit signals of S1, and receive signals at S2 are interfered by transmit signals of S2. An efficient method in order to combat this kind of interference is proposed in this paper. Furthermore, it is shown how the overall spectral efficiency of SDD relaying can be improved if the channels from S1 and S2 to the RS have different qualities.

  14. Performance Analysis of RF-FSO Multi-Hop Networks

    KAUST Repository

    Makki, Behrooz

    2017-05-12

    We study the performance of multi-hop networks composed of millimeter wave (MMW)-based radio frequency (RF) and free-space optical (FSO) links. The results are obtained in the cases with and without hybrid automatic repeat request (HARQ). Taking the MMW characteristics of the RF links into account, we derive closed-form expressions for the network outage probability. We also evaluate the effect of various parameters such as power amplifiers efficiency, number of antennas as well as different coherence times of the RF and the FSO links on the system performance. Finally, we present mappings between the performance of RF- FSO multi-hop networks and the ones using only the RF- or the FSO-based communication, in the sense that with appropriate parameter settings the same outage probability is achieved in these setups. The results show the efficiency of the RF-FSO setups in different conditions. Moreover, the HARQ can effectively improve the outage probability/energy efficiency, and compensate the effect of hardware impairments in RF-FSO networks. For common parameter settings of the RF-FSO dual- hop networks, outage probability 10^{-4} and code rate 3 nats-per-channel-use, the implementation of HARQ with a maximum of 2 and 3 retransmissions reduces the required power, compared to the cases with no HARQ, by 13 and 17 dB, respectively.

  15. Molecular dynamics simulations of electrosprayed water nanodroplets: internal potential gradients, location of excess charge centers, and "hopping" protons.

    Science.gov (United States)

    Ahadi, Elias; Konermann, Lars

    2009-05-21

    Water nanodroplets charged with excess protons play a central role during electrospray ionization (ESI). In the current study molecular dynamics (MD) simulations were used for gaining insights into the nanodroplet behavior based on classical mechanics. The SPC/E water model was modified to permit the inclusion of protons as highly mobile point charges at minimum computational cost. A spherical trapping potential was assigned to every SPC/E oxygen, thereby allowing the formation of protonated water molecules. Within a tightly packed nanodroplet the individual potential wells merge to form a three-dimensional energy landscape that facilitates rapid proton hopping between water molecules. This approach requires short-range modifications to the standard Coulomb potential for modeling electrostatic proton-water interactions. Simulations on nanodroplets consisting of 1248 water molecules and 10 protons (radius, ca. 21 A) result in a proton diffusion coefficient that is in agreement with the value measured in bulk solution. Radial proton distributions extracted from 1 ns MD runs exhibit a large peak around 14 A, in addition to substantial population density closer to the droplet center. Similar radial distributions were found for nanodroplets charged with Na+ ions. This behavior is dramatically different from that expected on the basis of continuum electrostatic theory, which predicts that excess charge should be confined to a thin layer on the droplet surface. One important contributor to this effect seems to be the ordering of water molecules at the liquid/vacuum interface. This ordering results in an electrical double layer, generating a potential gradient that tends to pull positive charge carriers (such as protons, but also others such as Na+ ions) toward the droplet interior. This deviation from the widely assumed surface charge paradigm could have implications for the mechanism by which protonated analyte ions are formed during ESI.

  16. Surface hopping with a manifold of electronic states. II. Application to the many-body Anderson-Holstein model.

    Science.gov (United States)

    Dou, Wenjie; Nitzan, Abraham; Subotnik, Joseph E

    2015-02-28

    We investigate a simple surface hopping (SH) approach for modeling a single impurity level coupled to a single phonon and an electronic (metal) bath (i.e., the Anderson-Holstein model). The phonon degree of freedom is treated classically with motion along--and hops between--diabatic potential energy surfaces. The hopping rate is determined by the dynamics of the electronic bath (which are treated implicitly). For the case of one electronic bath, in the limit of small coupling to the bath, SH recovers phonon relaxation to thermal equilibrium and yields the correct impurity electron population (as compared with numerical renormalization group). For the case of out of equilibrium dynamics, SH current-voltage (I-V) curve is compared with the quantum master equation (QME) over a range of parameters, spanning the quantum region to the classical region. In the limit of large temperature, SH and QME agree. Furthermore, we can show that, in the limit of low temperature, the QME agrees with real-time path integral calculations. As such, the simple procedure described here should be useful in many other contexts.

  17. Surface hopping with a manifold of electronic states. II. Application to the many-body Anderson-Holstein model

    Science.gov (United States)

    Dou, Wenjie; Nitzan, Abraham; Subotnik, Joseph E.

    2015-02-01

    We investigate a simple surface hopping (SH) approach for modeling a single impurity level coupled to a single phonon and an electronic (metal) bath (i.e., the Anderson-Holstein model). The phonon degree of freedom is treated classically with motion along-and hops between-diabatic potential energy surfaces. The hopping rate is determined by the dynamics of the electronic bath (which are treated implicitly). For the case of one electronic bath, in the limit of small coupling to the bath, SH recovers phonon relaxation to thermal equilibrium and yields the correct impurity electron population (as compared with numerical renormalization group). For the case of out of equilibrium dynamics, SH current-voltage (I-V) curve is compared with the quantum master equation (QME) over a range of parameters, spanning the quantum region to the classical region. In the limit of large temperature, SH and QME agree. Furthermore, we can show that, in the limit of low temperature, the QME agrees with real-time path integral calculations. As such, the simple procedure described here should be useful in many other contexts.

  18. Surface hopping with a manifold of electronic states. II. Application to the many-body Anderson-Holstein model

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Wenjie; Subotnik, Joseph E. [Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Nitzan, Abraham [School of Chemistry, The Sackler Faculty of Science, Tel Aviv University, Tel Aviv 69978 (Israel)

    2015-02-28

    We investigate a simple surface hopping (SH) approach for modeling a single impurity level coupled to a single phonon and an electronic (metal) bath (i.e., the Anderson-Holstein model). The phonon degree of freedom is treated classically with motion along–and hops between–diabatic potential energy surfaces. The hopping rate is determined by the dynamics of the electronic bath (which are treated implicitly). For the case of one electronic bath, in the limit of small coupling to the bath, SH recovers phonon relaxation to thermal equilibrium and yields the correct impurity electron population (as compared with numerical renormalization group). For the case of out of equilibrium dynamics, SH current-voltage (I-V) curve is compared with the quantum master equation (QME) over a range of parameters, spanning the quantum region to the classical region. In the limit of large temperature, SH and QME agree. Furthermore, we can show that, in the limit of low temperature, the QME agrees with real-time path integral calculations. As such, the simple procedure described here should be useful in many other contexts.

  19. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Science.gov (United States)

    Drakakis, E.; Kymakis, E.; Tzagkarakis, G.; Louloudakis, D.; Katharakis, M.; Kenanakis, G.; Suchea, M.; Tudose, V.; Koudoumas, E.

    2017-03-01

    We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4-20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  20. Isospin transport and reaction mechanism in nuclear reactions in the range 20–40 MeV/n

    Energy Technology Data Exchange (ETDEWEB)

    Barlini, S., E-mail: barlini@fi.infn.it; Piantelli, S.; Casini, G.; Olmi, A.; Bini, M.; Pasquali, G.; Poggi, G.; Stefanini, A. A.; Valdré, S.; Pastore, G. [Dipartimento di Fisica ed Astronomia dell’Università and INFN Sezione di Firenze, Firenze (Italy); Bougault, R.; Lopez, O.; Le Neindre, N.; Parlog, M.; Vient, E. [LPC, IN2P3-CNRS, ENSICAEN et Université de Caen, F-14050 Caen-Cedex (France); Bonnet, E.; Chibhi, A.; Frankland, J. D. [GANIL, CEA/DSM-CNRS/IN2P3, B.P.5027, F-14076 Caen cedex (France); Borderie, B.; Rivet, M. F. [Institut de Physique Nucléaire, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay cedex (France); and others

    2015-10-15

    In recent years, many efforts have been devoted to the investigation of the isospin degree of freedom in nuclear reactions. Comparing systems involving partners with different N/Z, it has been possible to investigate the isospin transport process and its influence on the final products population. This can be then related to the symmetry energy term of the nuclear EOS. From the experimental point of view, this task requires detectors able to measure both charge and mass of the emitted products, in the widest possible range of energy and size of the fragments. With this objective, the FAZIA and GARFIELD+RCo apparatus have been used with success in some recent experiments.

  1. Multi-Hop Link Capacity of Multi-Route Multi-Hop MRC Diversity for a Virtual Cellular Network

    Science.gov (United States)

    Daou, Imane; Kudoh, Eisuke; Adachi, Fumiyuki

    In virtual cellular network (VCN), proposed for high-speed mobile communications, the signal transmitted from a mobile terminal is received by some wireless ports distributed in each virtual cell and relayed to the central port that acts as a gateway to the core network. In this paper, we apply the multi-route MHMRC diversity in order to decrease the transmit power and increase the multi-hop link capacity. The transmit power, the interference power and the link capacity are evaluated for DS-CDMA multi-hop VCN by computer simulation. The multi-route MHMRC diversity can be applied to not only DS-CDMA but also other access schemes (i. e. MC-CDMA, OFDM, etc.).

  2. Population dynamics and integrated control of the damson-hop aphid Phorodon humuli (Schrank on hops in Spain

    Directory of Open Access Journals (Sweden)

    A. Lorenzana

    2013-04-01

    Full Text Available The hop aphid Phorodon humuli (Schrank (Hemiptera: Aphididae is a serious pest in most areas where hops are grown. A field trial was performed on a hop yard throughout 2002, 2003 and 2004 in León (Spain in order to analyse the population development of Phorodon humuli and its natural enemies, as well as to determine the most effective integrated program of insecticide treatments. The basic population development pattern of P. humuli was similar in the three years: the population peaked between mid to late June, and then decreased in late June/early July, rising again and reaching another peak in mid-July, after which it began to decline, rising once more in late August; this last rise is characteristic of Spain and has not been recorded in the rest of Europe. The hop aphid’s main natural enemy found on the leaves was Coccinella septempunctata (Coleoptera: Coccinellidae. The multiple regression analysis showed that aphids are positively related with the presence of beetle eggs and mean daily temperatures and negatively related with maximum daily temperature integral above 27ºC in plots without insecticide treatment. The most effective program of insecticide (imidacloprid treatments consisted of an initial treatment in June and a second treatment in the second half of July or at the beginning of August. However, a single treatment in June would be sufficient when in this last period the maximum daily temperatures were higher than 27ºC for at least 15 days, avoiding in this way the harmful effects of imidacloprid on predators.

  3. A spread spectrum system with frequency hopping and sequentially balanced modulation. II - Operation in jamming and multipath

    Science.gov (United States)

    Mathis, R. F.; Pawula, R. F.

    1980-10-01

    The performance of a spread spectrum system which incorporates frequency hopping, sequentially balanced modulation, phase-comparison tone ranging, and pseudoorthogonal block coding of BPSK data with maximum likelihood of soft decision decoding, is evaluated in jamming environments and multipath. The jamming models considered include partial-band noise jamming, comb-type partial-band noise jamming, multitone jamming, and comb-type multitone jamming. Specular multipath with broad-band noise are shown to be the most serious form of interference. Bit-error probability and ranging accuracy curves are presented.

  4. Potential macro-detritivore range expansion into the subarctic stimulates litter decomposition: a new positive feedback mechanism to climate change?

    Science.gov (United States)

    van Geffen, Koert G; Berg, Matty P; Aerts, Rien

    2011-12-01

    As a result of low decomposition rates, high-latitude ecosystems store large amounts of carbon. Litter decomposition in these ecosystems is constrained by harsh abiotic conditions, but also by the absence of macro-detritivores. We have studied the potential effects of their climate change-driven northward range expansion on the decomposition of two contrasting subarctic litter types. Litter of Alnus incana and Betula pubescens was incubated in microcosms together with monocultures and all possible combinations of three functionally different macro-detritivores (the earthworm Lumbricus rubellus, isopod Oniscus asellus, and millipede Julus scandinavius). Our results show that these macro-detritivores stimulated decomposition, especially of the high-quality A. incana litter and that the macro-detritivores tested differed in their decomposition-stimulating effects, with earthworms having the largest influence. Decomposition processes increased with increasing number of macro-detritivore species, and positive net diveristy effects occurred in several macro-detritivore treatments. However, after correction for macro-detritivore biomass, all interspecific differences in macro-detritivore effects, as well as the positive effects of species number on subarctic litter decomposition disappeared. The net diversity effects also appeared to be driven by variation in biomass, with a possible exception of net diversity effects in mass loss. Based on these results, we conclude that the expected climate change-induced range expansion of macro-detritivores into subarctic regions is likely to result in accelerated decomposition rates. Our results also indicate that the magnitude of macro-detritivore effects on subarctic decomposition will mainly depend on macro-detritivore biomass, rather than on macro-detritivore species number or identity.

  5. Deterministic Multi-hop Controlled Teleportation of Arbitrary Single-Qubit State

    Science.gov (United States)

    Peng, Jia-yin; Bai, Ming-qiang; Mo, Zhi-wen

    2017-10-01

    Multi-hop teleportation is of great significance due to long-distance delivery of quantum information and wireless quantum communication networks. In existing protocols of multi-hop teleportation, the more nodes, the smaller the success probability. In this paper, fusing the ideas of multi-hop teleportation and controlled teleportation, we put forward a scheme for implementing multi-hop controlled teleportation of single-qubit state. A set of ingenious three-qubit non-maximally entangled states are constructed to serve as the quantum channels. The information is perfectly transmitted hop by hop through teleportation under the control of the supervisors. Unit success probability can be achieved independent of channel's entanglement degree and the number of intermediate nodes. Only Pauli operations, single-qubit rotation, Hadamard gate, controlled-NOT gate, Bell-state measurement and single-qubit measurement are used in our scheme, so this scheme is easily realized in physical experiment.

  6. Blind Compressed Sensing Parameter Estimation of Non-cooperative Frequency Hopping Signal

    Directory of Open Access Journals (Sweden)

    Chen Ying

    2016-10-01

    Full Text Available To overcome the disadvantages of a non-cooperative frequency hopping communication system, such as a high sampling rate and inadequate prior information, parameter estimation based on Blind Compressed Sensing (BCS is proposed. The signal is precisely reconstructed by the alternating iteration of sparse coding and basis updating, and the hopping frequencies are directly estimated based on the results. Compared with conventional compressive sensing, blind compressed sensing does not require prior information of the frequency hopping signals; hence, it offers an effective solution to the inadequate prior information problem. In the proposed method, the signal is first modeled and then reconstructed by Orthonormal Block Diagonal Blind Compressed Sensing (OBD-BCS, and the hopping frequencies and hop period are finally estimated. The simulation results suggest that the proposed method can reconstruct and estimate the parameters of noncooperative frequency hopping signals with a low signal-to-noise ratio.

  7. Droppin’ Knowledge on Race: Hip-Hop, White Adolescents, and Anti-Racism Education

    Directory of Open Access Journals (Sweden)

    Steven Netcoh

    2013-10-01

    Full Text Available In this essay, the author examines how Hip-Hop can be mobilized in anti-racism educational initatives.  The author claims that existing research on Hip-Hop and white adolescents suggests a negative corrleation between white youths' engagement with Hip-Hop and their understanding of how race and racism function in American society.  In response to this research, the author argues Hip-Hop's diverse racial discourses and ideologies must be made the subject of direct and critical inquiry in secondary and post-secondary classrooms to maximize its democratic potential.  The author outlines specific approaches for how teachers can employ Hip-Hop in anti-racism curricula in secondary and post-secondary classrooms.  Collectively, the essay serves as a preliminary investigation of Hip-Hop pedagogies of race and whiteness.

  8. PERFORMANCE ANALYSIS OF ARQ AND HYBRID ARQ OVER SINGLE-HOP, DUAL-HOP, AND MULTIBRANCH DUAL-HOP NETWORKS

    KAUST Repository

    Hadjtaieb, Amir

    2014-05-01

    During the last decade, relay networks have attracted a lot of interest due to their numerous benefits. The relaying technique allows extending the coverage zone of wireless networks and offers a higher reliability for communication systems. The performance of relay networks can be improved further by the use of automatic repeat request (ARQ) and hybrid automatic repeat request (HARQ) techniques. ARQ and HARQ are retransmission mechanisms that ensure a good quality of service even in absence of channel state information at the transmitter. We, firstly, study the spectral and energy efficiency of ARQ in Nakagami-m block-fading channels. We maximize both spectral efficiency and energy efficiency with respect to the transmitted power. We derive exact expressions as well as compact and tight approximation for the solutions of these problems. Our analysis shows that the two problems of maximizing spectral efficiency and energy efficiency with respect to the transmitted power are completely different and give different solutions. Additionally, operating with a power that maximizes energy efficiency can lead to a significant drop in the spectral efficiency, and vice versa. Next, we consider a three node relay network comprising a source, a relay, and a destination. The source transmits the message to the destination using HARQ with incremental redundancy (IR). The relay overhears the transmitted message, amplifies it using a variable gain amplifier, and then forwards the message to the destination. This latter combines both the source and the relay message and tries to decode the information. In case of decoding failure, the destination sends a negative acknowledgement. A new replica of the message containing new parity bits is then transmitted in the subsequent HARQ round. This process continues until successful decoding occurs at the destination or a maximum number M of rounds is reached. We study the performance of HARQ-IR over the considered relay channel from an

  9. On the contribution of local feedback mechanisms to the range of climate sensitivity in two GCM ensembles

    Energy Technology Data Exchange (ETDEWEB)

    Webb, M.J.; Senior, C.A.; Sexton, D.M.H.; Ingram, W.J.; Williams, K.D.; Ringer, M.A. [Hadley Centre for Climate Prediction and Research, Met Office, Exeter (United Kingdom); McAvaney, B.J.; Colman, R. [Bureau of Meteorology Research Centre (BMRC), Melbourne (Australia); Soden, B.J. [University of Miami, Rosenstiel School for Marine and Atmospheric Science, Miami, FL (United States); Gudgel, R.; Knutson, T. [Geophysical Fluid Dynamics Laboratory (GFDL), Princeton, NJ (United States); Emori, S.; Ogura, T. [National Institute for Environmental Studies (NIES), Tsukuba (Japan); Tsushima, Y. [Japan Agency for Marine-Earth Science and Technology, Frontier Research Center for Global Change (FRCGC), Kanagawa (Japan); Andronova, N. [University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI (United States); Li, B. [University of Illinois at Urbana-Champaign (UIUC), Department of Atmospheric Sciences, Urbana, IL (United States); Musat, I.; Bony, S. [Institut Pierre Simon Laplace (IPSL), Paris (France); Taylor, K.E. [Program for Climate Model Diagnosis and Intercomparison (PCMDI), Livermore, CA (United States)

    2006-07-15

    Global and local feedback analysis techniques have been applied to two ensembles of mixed layer equilibrium CO{sub 2} doubling climate change experiments, from the CFMIP (Cloud Feedback Model Intercomparison Project) and QUMP (Quantifying Uncertainty in Model Predictions) projects. Neither of these new ensembles shows evidence of a statistically significant change in the ensemble mean or variance in global mean climate sensitivity when compared with the results from the mixed layer models quoted in the Third Assessment Report of the IPCC. Global mean feedback analysis of these two ensembles confirms the large contribution made by inter-model differences in cloud feedbacks to those in climate sensitivity in earlier studies; net cloud feedbacks are responsible for 66% of the inter-model variance in the total feedback in the CFMIP ensemble and 85% in the QUMP ensemble. The ensemble mean global feedback components are all statistically indistinguishable between the two ensembles, except for the clear-sky shortwave feedback which is stronger in the CFMIP ensemble. While ensemble variances of the shortwave cloud feedback and both clear-sky feedback terms are larger in CFMIP, there is considerable overlap in the cloud feedback ranges; QUMP spans 80% or more of the CFMIP ranges in longwave and shortwave cloud feedback. We introduce a local cloud feedback classification system which distinguishes different types of cloud feedbacks on the basis of the relative strengths of their longwave and shortwave components, and interpret these in terms of responses of different cloud types diagnosed by the International Satellite Cloud Climatology Project simulator. In the CFMIP ensemble, areas where low-top cloud changes constitute the largest cloud response are responsible for 59% of the contribution from cloud feedback to the variance in the total feedback. A similar figure is found for the QUMP ensemble. Areas of positive low cloud feedback (associated with reductions in low level

  10. Structural influence on atomic hopping and electronic states of Pd-based bulk metallic glasses

    OpenAIRE

    Tang, X.-P.; Löffler, Jörg F.; Schwarz, R. B.; Johnson, William L.; Wu, Yue

    2005-01-01

    Atomic motion and electronic structures of Pd–Ni–Cu–P bulk metallic glasses were investigated using 31P nuclear magnetic resonance. The hopping rate of P atoms was determined by the stimulated echo technique. Significant hopping was observed in all alloys well below the glass transition temperature. Increasing the Cu content to above 25 at. % increases P hopping significantly, consistent with the previous finding that the openness of the structure increases with Cu content. In contrast, P h...

  11. Hole hopping rates in single strand oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Borrelli, Raffaele [Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, I-10095 Grugliasco, TO (Italy); Capobianco, Amedeo [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy); Peluso, Andrea, E-mail: apeluso@unisa.it [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy)

    2014-08-31

    Highlights: • DNA hole transfer rates have been computed. • Delocalized adenine domains significantly affect hole transfer rates in DNA. • Franck–Condon weighted density of state from DFT normal modes. • DNA application in molecular electronics. - Abstract: The rates of hole transfer between guanine and adenine in single strand DNA have been evaluated by using Fermi’s golden rule and Kubo’s generating function approach for the Franck–Condon weighted density of states. The whole sets of the normal modes and vibrational frequencies of the two nucleobases, obtained at DFT/B3LYP level of calculation, have been considered in computations. The results show that in single strand the pyramidalization/planarization mode of the amino groups of both nucleobases plays the major role. At room temperature, the Franck–Condon density of states extends over a wide range of hole site energy difference, 0–1 eV, giving some hints about the design of oligonucleotides of potential technological interest.

  12. An Adaptable Spectrin/Ankyrin-Based Mechanism for Long-Range Organization of Plasma Membranes in Vertebrate Tissues.

    Science.gov (United States)

    Bennett, Vann; Lorenzo, Damaris N

    2016-01-01

    Ankyrins are membrane-associated proteins that together with their spectrin partners are responsible for micron-scale organization of vertebrate plasma membranes, including those of erythrocytes, excitable membranes of neurons and heart, lateral membrane domains of columnar epithelial cells, and striated muscle. Ankyrins coordinate functionally related membrane transporters and cell adhesion proteins (15 protein families identified so far) within plasma membrane compartments through independently evolved interactions of intrinsically disordered sequences with a highly conserved peptide-binding groove formed by the ANK repeat solenoid. Ankyrins are coupled to spectrins, which are elongated organelle-sized proteins that form mechanically resilient arrays through cross-linking by specialized actin filaments. In addition to protein interactions, cellular targeting and assembly of spectrin/ankyrin domains also critically depend on palmitoylation of ankyrin-G by aspartate-histidine-histidine-cysteine 5/8 palmitoyltransferases, as well as interaction of beta-2 spectrin with phosphoinositide lipids. These lipid-dependent spectrin/ankyrin domains are not static but are locally dynamic and determine membrane identity through opposing endocytosis of bulk lipids as well as specific proteins. A partnership between spectrin, ankyrin, and cell adhesion molecules first emerged in bilaterians over 500 million years ago. Ankyrin and spectrin may have been recruited to plasma membranes from more ancient roles in organelle transport. The basic bilaterian spectrin-ankyrin toolkit markedly expanded in vertebrates through gene duplications combined with variation in unstructured intramolecular regulatory sequences as well as independent evolution of ankyrin-binding activity by ion transporters involved in action potentials and calcium homeostasis. In addition, giant vertebrate ankyrins with specialized roles in axons acquired new coding sequences by exon shuffling. We speculate that

  13. Block-and-Matrix Serpentinite Emplacement Mechanisms in the California Coast Ranges from 35 to 39° N: A Review

    Science.gov (United States)

    Kellner, C. R.

    2016-12-01

    We review the large geological literature on serpentinite emplacement mechanisms based on field relations described in dozens of articles on specific serpentinite localities in California. Many of these papers focused on the numerous mercury mines that were associated with serpentinite bodies and their partial alteration to silica-carbonate rocks and mercury metallization by carbonated hydrothermal alteration. USGS Geologists Edgar Bailey, Don Everhart, Frank Wells, Clyde Ross, and Robert Coleman, had access to extensive underground mercury mine workings and this access afforded these authors three-dimensional information on the geometries and contact relations of fresh serpentinites with host rocks (Ross, 1940a & b. Bailey, 1942, 1946, 1948, 1951; Bailey and Myers, 1942; Bailey, 1964; Bailey and Myers, 1942; Bailey, Irwin, and Jones, 1964; Wells, 1951; Coleman, 1957). Their unequivocal view was that members of this class of serpentinite bodies were emplaced as serpentinites by "cold-intrusion" as sills, dikes, plugs, and along faults. Other geologists have shared this view (Turner and Verhoogen, 1951; Page, 1966, 1967; Page, de Vito, and Coleman, 1999; Coleman, 1971; Lockwood, 1972; Murata, et. al., 1979). Serpentinites along contacts are described as sheared and these bodies shared many of the geological features of igneous intrusions such as branching, lenticular shapes, and pinch-and-swell geometries, but lacked the mineralogy of high-temperature contact metamorphism. Many of these classic papers have evidently have been forgotten. A recent paper posits a large mantle source of water from the former forearc during the Mesozoic and Paleogene subduction era and after the transition to transpressive continental-transform kinematics of the San Andreas Fault System (Kirby, Wang, and Brocher, Earth Planets and Space 2014; Kirby, 2015 AGU Abstract). This model gives insights into both the source of these serpentinite bodies and their rheological mobilization by a

  14. A Review of Hip Hop-Based Interventions for Health Literacy, Health Behaviors, and Mental Health.

    Science.gov (United States)

    Robinson, Cendrine; Seaman, Elizabeth L; Montgomery, LaTrice; Winfrey, Adia

    2017-07-01

    African-American children and adolescents experience an undue burden of disease for many health outcomes compared to their White peers. More research needs to be completed for this priority population to improve their health outcomes and ameliorate health disparities. Integrating hip hop music or hip hop dance into interventions may help engage African-American youth in health interventions and improve their health outcomes. We conducted a review of the literature to characterize hip hop interventions and determine their potential to improve health. We searched Web of Science, Scopus, PsycINFO, and EMBASE to identify studies that assessed hip hop interventions. To be included, studies had to (1) be focused on a psychosocial or physical health intervention that included hip hop and (2) present quantitative data assessing intervention outcomes. Twenty-three articles were identified as meeting all inclusion criteria and were coded by two reviewers. Articles were assessed with regards to sample characteristics, study design, analysis, intervention components, and results. Hip hop interventions have been developed to improve health literacy, health behavior, and mental health. The interventions were primarily targeted to African-American and Latino children and adolescents. Many of the health literacy and mental health studies used non-experimental study designs. Among the 12 (of 14) health behavior studies that used experimental designs, the association between hip hop interventions and positive health outcomes was inconsistent. The number of experimental hip hop intervention studies is limited. Future research is required to determine if hip hop interventions can promote health.

  15. Helicobacter pylori adhesin HopQ engages in a virulence-enhancing interaction with human CEACAMs.

    Science.gov (United States)

    Javaheri, Anahita; Kruse, Tobias; Moonens, Kristof; Mejías-Luque, Raquel; Debraekeleer, Ayla; Asche, Carmen I; Tegtmeyer, Nicole; Kalali, Behnam; Bach, Nina C; Sieber, Stephan A; Hill, Darryl J; Königer, Verena; Hauck, Christof R; Moskalenko, Roman; Haas, Rainer; Busch, Dirk H; Klaile, Esther; Slevogt, Hortense; Schmidt, Alexej; Backert, Steffen; Remaut, Han; Singer, Bernhard B; Gerhard, Markus

    2016-10-17

    Helicobacter pylori specifically colonizes the human gastric epithelium and is the major causative agent for ulcer disease and gastric cancer development. Here, we identify members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family as receptors of H. pylori and show that HopQ is the surface-exposed adhesin that specifically binds human CEACAM1, CEACAM3, CEACAM5 and CEACAM6. HopQ-CEACAM binding is glycan-independent and targeted to the N-domain. H. pylori binding induces CEACAM1-mediated signalling, and the HopQ-CEACAM1 interaction enables translocation of the virulence factor CagA into host cells and enhances the release of pro-inflammatory mediators such as interleukin-8. Based on the crystal structure of HopQ, we found that a β-hairpin insertion (HopQ-ID) in HopQ's extracellular 3+4 helix bundle domain is important for CEACAM binding. A peptide derived from this domain competitively inhibits HopQ-mediated activation of the Cag virulence pathway, as genetic or antibody-mediated abrogation of the HopQ function shows. Together, our data suggest the HopQ-CEACAM1 interaction to be a potentially promising novel therapeutic target to combat H. pylori-associated diseases.

  16. Hip-hop as a resource for understanding the urban context

    Science.gov (United States)

    Brown, Bryan

    2010-06-01

    This review explores Edmin's "Science education for the hip-hop generation" by documenting how he frames hip-hop as a means to access urban student culture. He argues that hip-hop is more than a mere music genre, but rather a culture that provides young people with ways of connecting to the world. Two primary ideas emerged as central to his work. First, he contends that students develop communal relationships and collective identities based on the common experiences expressed in hip-hop. Second, he identifies how the conscious recognition of institutional oppression serves a central feature in urban schools. Emdin's rich, and personal call for a greater understanding of hip-hop culture provides the text with an unmatched strength. He skillfully uses personal narratives from his own experience as well as quotes and references from hip-hop songs to make the nuances of hip hop transparent to science educators. Conversely, the limitation of this text is found in its unfulfilled promise to provide pragmatic examples of how to engage in a hip-hop based science education. Emdin's work is ultimately valuable as it extends our current knowledge about urban students and hip-hop in meaningful ways.

  17. Cu1–xFexO: hopping transport and ferromagnetism

    Science.gov (United States)

    Nasir, Mohd.; Islam, Rakibul; Ahmed, Md. A; Ayaz, Saniya; Kumar, Gautham; Kumar, Sunil; Prajapat, C. L.; Roussel, Frederick; Biring, Sajal

    2017-01-01

    Single phase, sol–gel prepared Cu1–xFexO (0 ≤ x ≤ 0.125) powders are characterized in terms of structural, electronic and magnetic properties. Using dielectric and magnetic studies we investigate the coupling of electron and spin. The electrical conductivities and activation energies are studied with increasing Fe content. Modelling of experimental conductivity data emphasizes a single hopping mechanism for all samples except x = 0.125, which have two activation energies. Hole doping is confirmed by confirming a majority Fe3+ substitution of Cu2+ in CuO from X-ray photoelectron spectroscopy studies (XPS). Such a substitution results in stabilized ferromagnetism. Fe substitution introduces variation in coercivity as an intrinsic magnetic property in Fe-doped CuO, and not as a secondary impurity phase. PMID:28989741

  18. Geração hip-hop e a construção do imaginário na periferia do Distrito Federal

    Directory of Open Access Journals (Sweden)

    Breitner Tavares

    2010-08-01

    Full Text Available Este artigo propõe observar elementos gerais referentes à construção de um estilo de vida hip-hop em termos de suas origens históricas de uma cultura planetária e, em especial, como fator preponderante para a configuração geracional. Para isso, se discute algumas trajetórias biográficas concernentes a uma configuração da cultura hip-hop vivenciada por jovens do Distrito Federal, compreendida como mecanismo produtor de orientações coletivas para uma determinada visão de mundo.This article observes some general elements about the construction of hip hop's life style in terms of its historical origins of a planetary culture and in special, as around the young culture as preponderant factor for the generation configuration. Consequently, this paper analises some biographical trajectories about the configuration of the hip-hop culture lived deeply by young people in Brasilia (Federal Distric - Brazil, understood as a mechanism of its collective social role and vision of world.

  19. Thermally assisted variable range hopping in Tl4S3Se crystal

    Indian Academy of Sciences (India)

    This new approach corrects the evaluated electrical parameters that are necessary for the construction of electronic devices like absorption layers in solar cells. ... Departments of Mathematics and Physics, Arab American University, Jenin 240, Palestine; Group of Physics, Faculty of Engineering, Atilim University, 06836 ...

  20. Child-Mediated Stroke Communication: findings from Hip Hop Stroke.

    Science.gov (United States)

    Williams, Olajide; DeSorbo, Alexandra; Noble, James; Gerin, William

    2012-01-01

    Low thrombolysis rates for acute ischemic stroke are linked to delays in seeking immediate treatment due to low public stroke awareness. We aimed to assess whether "Child-Mediated Stroke Communication" could improve stroke literacy of parents of children enrolled in a school-based stroke literacy program called Hip Hop Stroke. Parents of children aged 9 to 12 years from 2 public schools in Harlem, New York City, were recruited to participate in stroke literacy questionnaires before and after their child's participation in Hip Hop Stroke, a novel Child-Mediated Stroke Communication intervention delivered in school auditoriums. Parental recall of stroke information communicated through their child was assessed 1-week after the intervention. Fifth and sixth grade students (n=182) were enrolled into Hip Hop Stroke. One hundred two parents were approached in person to participate; 75 opted to participate and 71 completed both the pretest and post-test (74% response rate and 95% retention rate). Parental stroke literacy improved after the program; before the program, 3 parents of 75 (3.9%) were able to identify the 5 cardinal stroke symptoms, distracting symptom (chest pains), and had an urgent action plan (calling 911) compared with 21 of 71 parents (29.6%) postintervention (P<0.001). The FAST mnemonic was known by 2 (2.7%) of participants before the program versus 29 (41%) after program completion (P<0.001). Knowledge of stroke signs and symptoms remains low among residents of this high-risk population. The use of Child-Mediated Stroke Communication suggests that school children aged 9 to 12 years may be effective conduits of critical stroke knowledge to their parents.

  1. Exploiting sparsity in free energy basin-hopping

    Science.gov (United States)

    Sutherland-Cash, Kyle H.; Mantell, Rosemary G.; Wales, David J.

    2017-10-01

    We present acceleration of the vibrational frequency calculations required in free energy basin-hopping (FEBH) global optimisation using sparse Cholesky factorisation. We describe an interface with the SuiteSparse software package that facilitates these calculations, and present results detailing the accuracy and speedups obtained for atomic clusters and biomolecules. For the larger systems, exploiting sparsity reduces the computational cost by factors of ten to thirty, with no significant loss in accuracy. This approach will therefore provide access to the vibrational density of states, and hence to local harmonic free energies, for structure prediction and thermodynamic properties of more complex systems.

  2. Spectral Efficiency of Random Time-Hopping CDMA

    OpenAIRE

    Ferrante, Guido Carlo; Di Benedetto, Maria-Gabriella

    2013-01-01

    Traditionally paired with impulsive communications, Time-Hopping CDMA (TH-CDMA) is a multiple access technique that separates users in time by coding their transmissions into pulses occupying a subset of $N_\\mathsf{s}$ chips out of the total $N$ included in a symbol period, in contrast with traditional Direct-Sequence CDMA (DS-CDMA) where $N_\\mathsf{s}=N$. This work analyzes TH-CDMA with random spreading, by determining whether peculiar theoretical limits are identifiable, with both optimal a...

  3. The Analysis Of Slang Words In Selected Hip Hop Songs

    OpenAIRE

    Manalu, Sadrakh Anthony

    2015-01-01

    Slang is a language structure that evolved in modern times that in his particular use by young people. Slang develops in tune with its evolving culture in the environment so that the slang does not have a time, place or community background limit. Slang can also be found in almost every language in the world, in this case the author discusses the use of slang words contained in the English language in specialized its African American Hip Hop culture. In this paper entitled "The Analysis of Sl...

  4. High-Speed On-Board Data Processing for Science Instruments: HOPS

    Science.gov (United States)

    Beyon, Jeffrey

    2015-01-01

    The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program during April, 2012 â€" April, 2015. HOPS is an enabler for science missions with extremely high data processing rates. In this three-year effort of HOPS, Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) and 3-D Winds were of interest in particular. As for ASCENDS, HOPS replaces time domain data processing with frequency domain processing while making the real-time on-board data processing possible. As for 3-D Winds, HOPS offers real-time high-resolution wind profiling with 4,096-point fast Fourier transform (FFT). HOPS is adaptable with quick turn-around time. Since HOPS offers reusable user-friendly computational elements, its FPGA IP Core can be modified for a shorter development period if the algorithm changes. The FPGA and memory bandwidth of HOPS is 20 GB/sec while the typical maximum processor-to-SDRAM bandwidth of the commercial radiation tolerant high-end processors is about 130-150 MB/sec. The inter-board communication bandwidth of HOPS is 4 GB/sec while the effective processor-to-cPCI bandwidth of commercial radiation tolerant high-end boards is about 50-75 MB/sec. Also, HOPS offers VHDL cores for the easy and efficient implementation of ASCENDS and 3-D Winds, and other similar algorithms. A general overview of the 3-year development of HOPS is the goal of this presentation.

  5. EFFICACY OF KALTENBORN GRADE III MOBILIZATIONS, MUSCLE ENERGY TECHNIQUES AND THEIR COMBINATION TO IMPROVE RANGE AND FUNCTIONAL ABILITY IN ADULTS WITH MECHANICAL NECK PAIN

    Directory of Open Access Journals (Sweden)

    Naveed Anwar

    2016-08-01

    Full Text Available Background: Physiotherapy is an essentialtreatment in the management of Mechanical Neck ache, still there was lack of literature seen supporting the effectiveness of Physiotherapy interventions with their doses targeting specific group of population. The focus of study was to see the effectiveness of Kaltenborn Grade III mobilization, Muscle Energy Techniques and their combination to improve range and functional ability in patients with Mechanical Neck ache. Methods: 72 patients with Mechanical Neck achewere randomly categorized in 3 groups (Mobilization, METs and Combination group. NDI scale and goniometry was used as an assessment tool to measure the outcome before and after treatment (follow up 1 week. Results: According to the results there was significant improvement seen in Combination group (Mobilization and METs in terms of pain, which decreased from 7.70±0.69 to 1.25±1.93 (p=0.00, gain in ROM e.g. Cervical Flexion (27.29±2.38 to 37.54±3.14. Whereas, marked significance (p=0.00 was seen in the NDI score and percentage of Combination group. ANOVA tells us that difference was significant in all three groups in categories of pain (VAS, gain in cervical ranges and NDI score and percentage as p=0.00. Combination group had significant difference within the groups then METs and Mobilization group in all categories of VAS, Cervical ranges, NDI score and percentage. Conclusion: Combination of (Grade III Kaltenborn and METs was seen more effective in terms of improving Mechanical Neck Pain, in smaller treatment session (7 days only.

  6. Dry needling: Effects on activation and passive mechanical properties of the quadriceps, pain and range during late stage rehabilitation of ACL reconstructed patients.

    Science.gov (United States)

    Ortega-Cebrian, Silvia; Luchini, Nicolleta; Whiteley, Rodney

    2016-09-01

    Dry needling (DN) is reported to decrease pain and improve functional movements yet the mechanisms remain unclear. Changes in muscle tone and other mechanical properties after DN could contribute to these findings but have not been investigated. Examine EMG and passive mechanical properties of the quadriceps muscle before and after DN. EMG, MyotonPro and clinical measurements were taken pre and post DN. Rehabilitation department at Aspetar Sports Medicine Hospital, Qatar. 20 subjects reporting pain and quadriceps muscle tension. Pain (VAS, measured during a single leg step down), knee flexion range, and passive mechanical properties of the superficial quadriceps were measured using the MyotonPro device. Pain decreased (p  0.11, ES = 0.13). Passive mechanical properties were not significantly different in rectus femoris (RF) and VL. Decrement and Resistance of the Vastus Medialis (VM) were significantly decreased (p0.19). DN resulted in small reductions in: pain, resting activation (EMG of VL), decrement and resistance (of VM). Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Topography, structure, and formation kinetic mechanism of carbon deposited onto nickel in the temperature range from 400 to 850°C

    Science.gov (United States)

    Chen, Zhi-yuan; Bian, Liu-zhen; Wang, Li-jun; Yu, Zi-you; Zhao, Hai-lei; Li, Fu-shen; Chou, Kuo-chih

    2017-05-01

    The carbon deposition behavior on nickel particles was observed within the temperature range from 400 to 800°C in a pure methane atmosphere. The topography, properties, and molecular structure of the deposited carbon were investigated using field-emission scanning electron microscopy (FESEM), temperature-programmed oxidation (TPO) technology, X-ray diffraction (XRD), and Raman spectroscopy. The deposited carbon is present in the form of a film at 400-450°C, as fibers at 500-600°C, and as particles at 650-800°C. In addition, the structure of the deposited carbon becomes more ordered at higher temperatures because both the TPO peak temperature of deposited carbon and the Raman shift of the G band increase with the increase in experimental temperature, whereas the intensity ratio between the D bands and the G band decreases. An interesting observation is that the carbon deposition rate is suppressed in the medium-temperature range (M-T range) and the corresponding kinetic mechanism changes. Correspondingly, the FWHM of the G and D1 bands in the Raman spectrum reaches a maximum and the intensities of the D2, D3, and D4 bands decrease to low limits in the M-T range. These results indicate that carbon structure parameters exhibit two different tendencies with respect to varying temperature. Both of the two group parameters change dramatically as a peak function with increasing reaction temperature within the M-T range.

  8. Determination of volatile compounds in different hop varieties by headspace-trap GC/MS--in comparison with conventional hop essential oil analysis.

    Science.gov (United States)

    Aberl, Anita; Coelhan, Mehmet

    2012-03-21

    A headspace (HS)-trap method in combination with gas chromatography (GC)-mass spectrometry (MS) was developed for the determination of volatile constituents in hops. The highly sensitive HS-trap system reduces the detection limit by using up to four trap enrichment cycles. Seventy hop samples of different varieties and cultivation regions, from the 2008 harvest, were examined using the HS-trap-GC-MS method and the established "European Brewery Convention" (EBC) method for hop essential oil analysis. Twenty-one different volatiles were quantified for each hop sample. For all compounds, except caryophyllene oxide, a strong correlation was found between the results of the HS-trap method and the EBC method. Experiments have revealed that the EBC method using steam distillation is not appropriate for thermolabile compounds, such as caryophyllene oxide, due to decomposition during boiling. The HS-trap method is fast and sensitive, requires small sample amounts and minimal sample preparation, and is easy to apply.

  9. A decentralized scheduling algorithm for time synchronized channel hopping

    Directory of Open Access Journals (Sweden)

    Andrew Tinka

    2011-09-01

    Full Text Available Time Synchronized Channel Hopping (TSCH is an existing Medium Access Control scheme which enables robust communication through channel hopping and high data rates through synchronization. It is based on a time-slotted architecture, and its correct functioning depends on a schedule which is typically computed by a central node. This paper presents, to our knowledge, the first scheduling algorithm for TSCH networks which both is distributed and which copes with mobile nodes. Two variations on scheduling algorithms are presented. Aloha-based scheduling allocates one channel for broadcasting advertisements for new neighbors. Reservation- based scheduling augments Aloha-based scheduling with a dedicated timeslot for targeted advertisements based on gossip information. A mobile ad hoc motorized sensor network with frequent connectivity changes is studied, and the performance of the two proposed algorithms is assessed. This performance analysis uses both simulation results and the results of a field deployment of floating wireless sensors in an estuarial canal environment. Reservation-based scheduling performs significantly better than Aloha-based scheduling, suggesting that the improved network reactivity is worth the increased algorithmic complexity and resource consumption.

  10. Augmented Ehrenfest dynamics yields a rate for surface hopping

    Science.gov (United States)

    Subotnik, Joseph E.

    2010-04-01

    We present a new algorithm for mixed quantum-classical dynamics that helps bridge the gap between mean-field (Ehrenfest) and surface-hopping dynamics by defining a natural rate of decoherence. In order to derive this decoherence result, we have expanded the number of independent variables in the usual Ehrenfest routine so that mixed quantum-classical derivatives are now propagated in time alongside the usual Ehrenfest variables. Having done so, we compute a unique rate of decoherence using two independent approaches: (i) by comparing the equations of motion for the joint nuclear-electronic probability density in phase space according to Ehrenfest dynamics versus partial Wigner transform dynamics and (ii) by introducing a frozen Gaussian interpretation of Ehrenfest dynamics which allows nuclear wave packets to separate. The first consequence of this work is a means to rigorously check the accuracy of standard Ehrenfest dynamics. Second, this paper suggests a nonadiabatic dynamics algorithm, whereby the nuclei are propagated on the mean-field (Ehrenfest) potential energy surface and undergo stochastic decoherence events. Our work resembles the surface-hopping algorithm of Schwartz and co-workers [J. Chem. Phys. 123, 234106 (2005)]—only now without any adjustable parameters. For the case of two electronic states, we present numerical results on the so-called "Tully problems" and emphasize that future numerical benchmarking is still needed. Future work will also treat the problem of three or more electronic states.

  11. Problem Formulation and Analysis of the 1-Hop ARQ Links

    Science.gov (United States)

    Cheung, K.-M.

    2013-08-01

    In space communications, standard link analysis assumes that messages are sent once. For a communication link that uses an error-correction coding scheme, bit-error rate (BER) or frame-error rate (FER), and link margins are common metrics that characterize the quality of a link, and they are used to determine the supportable data rate. With the advent of Automatic Repeat-reQuest (ARQ) protocols, when messages are corrupted during transmission, they can be resent multiple times automatically until they are correctly received and acknowledged. The concept of BER, FER, and link margin cannot be directly applied, and the link analysis approach for ARQ links needs to be reexamined. In this article, we provide the problem formulation and extend the standard link analysis approach to a 1-hop ARQ link (no routing), under the assumption that code-block errors occur independently as in the case of space communications. We develop analytical models that describe the statistical behavior of standard 1-hop ARQ links. By integrating these analytical ARQ protocol models into the standard link analysis, we bypass the need to simulate or emulate the ARQ protocol operations, and generate relevant statistics on effective data rate, effective throughput, latency, and FER.

  12. Surface-hopping dynamics and decoherence with quantum equilibrium structure.

    Science.gov (United States)

    Grunwald, Robbie; Kim, Hyojoon; Kapral, Raymond

    2008-04-28

    In open quantum systems, decoherence occurs through interaction of a quantum subsystem with its environment. The computation of expectation values requires a knowledge of the quantum dynamics of operators and sampling from initial states of the density matrix describing the subsystem and bath. We consider situations where the quantum evolution can be approximated by quantum-classical Liouville dynamics and examine the circumstances under which the evolution can be reduced to surface-hopping dynamics, where the evolution consists of trajectory segments exclusively evolving on single adiabatic surfaces, with probabilistic hops between these surfaces. The justification for the reduction depends on the validity of a Markovian approximation on a bath averaged memory kernel that accounts for quantum coherence in the system. We show that such a reduction is often possible when initial sampling is from either the quantum or classical bath initial distributions. If the average is taken only over the quantum dispersion that broadens the classical distribution, then such a reduction is not always possible.

  13. Robust hopping based on virtual pendulum posture control.

    Science.gov (United States)

    Sharbafi, Maziar A; Maufroy, Christophe; Ahmadabadi, Majid Nili; Yazdanpanah, Mohammad J; Seyfarth, Andre

    2013-09-01

    A new control approach to achieve robust hopping against perturbations in the sagittal plane is presented in this paper. In perturbed hopping, vertical body alignment has a significant role for stability. Our approach is based on the virtual pendulum concept, recently proposed, based on experimental findings in human and animal locomotion. In this concept, the ground reaction forces are pointed to a virtual support point, named virtual pivot point (VPP), during motion. This concept is employed in designing the controller to balance the trunk during the stance phase. New strategies for leg angle and length adjustment besides the virtual pendulum posture control are proposed as a unified controller. This method is investigated by applying it on an extension of the spring loaded inverted pendulum (SLIP) model. Trunk, leg mass and damping are added to the SLIP model in order to make the model more realistic. The stability is analyzed by Poincaré map analysis. With fixed VPP position, stability, disturbance rejection and moderate robustness are achieved, but with a low convergence speed. To improve the performance and attain higher robustness, an event-based control of the VPP position is introduced, using feedback of the system states at apexes. Discrete linear quartic regulator is used to design the feedback controller. Considerable enhancements with respect to stability, convergence speed and robustness against perturbations and parameter changes are achieved.

  14. OFDMA Cellular Networks with Opportunistic Two-Hop Relays

    Directory of Open Access Journals (Sweden)

    Calcev George

    2009-01-01

    Full Text Available We investigate the benefits of two-hop opportunistic relay in time division duplex (TDD OFDMA cellular network configurations. The paper starts with a short analytical model for the two-hop opportunistic relay. The model expresses the probability of finding a suitable relay node in the presence of lognormal fading and it allows the computation of the expected number of out-of-coverage nodes, as well as the end-to-end spectrum efficiency increase due to opportunistic relaying. The paper then presents results for Monte Carlo simulations of opportunistic relay in some realistic scenarios. Specifically, the simulations consider two scenarios. The first scenario uses the propagation model and a wide-area 19-cell configuration specified in 802.16 OFDMA cellular standard evaluation methodologies. In the second scenario, a Manhattan-like 19-cell topology is used. Our simulations show 11% to 33% in throughput increase when the opportunistic relay technology is used. Our results evaluate the benefits of the opportunistic relay in both scenarios in terms of coverage extension and throughput increase.

  15. Hip-Hop to Health Jr. for Latino preschool children.

    Science.gov (United States)

    Fitzgibbon, Marian L; Stolley, Melinda R; Schiffer, Linda; Van Horn, Linda; KauferChristoffel, Katherine; Dyer, Alan

    2006-09-01

    Hip-Hop to Health Jr. was a diet/physical activity intervention designed to reduce gains in BMI (kilograms per meter squared) in preschool minority children. Twelve predominantly Latino Head Start centers participated in a group-randomized trial conducted between Fall 2001 and Winter 2003. Six centers were randomized to a culturally proficient 14-week (three times weekly) diet/physical activity intervention. Parents participated by completing weekly homework assignments. The children in the other six centers received a general health intervention that did not address either diet or physical activity. The primary outcome was change in BMI, and secondary outcomes were changes in dietary intake and physical activity. Measures were collected at baseline, post-intervention, and at Years 1 and 2 follow-up. There were no significant differences between intervention and control schools in either primary or secondary outcomes at post-intervention, Year 1, or Year 2 follow-ups. When Hip-Hop to Health Jr. was conducted in predominantly black Head Start centers, it was effective in reducing subsequent increases in BMI in preschool children. In contrast, when the program was conducted in Latino centers, it was not effective. Although the intervention did not prevent excessive weight gain in Latino children, it was very well received. Future interventions with this population may require further cultural tailoring and a more robust parent intervention.

  16. Hops 383: an Outbursting Class 0 Protostar in Orion

    Science.gov (United States)

    Safron, Emily J.; Fischer, William J.; Megeath, S. Thomas; Furlan, Elise; Stutz, Amelia M.; Stanke, Thomas; Billot, Nicolas; Rebull, Luisa M.; Tobin, John J.; Ali, Babar; Allen, Lori E.; Booker, Joseph; Watson, Dan M.; Wilson, T. L.

    2015-02-01

    We report the dramatic mid-infrared brightening between 2004 and 2006 of Herschel Orion Protostar Survey (HOPS) 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 μm with a brightness increase also apparent at 4.5 μm. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM Ks imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 {{L}⊙ }. Post-outburst time-series mid- and far-infrared photometry show no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a 6 year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.

  17. Link and route availability for Inter-working multi-hop wireless networks

    CSIR Research Space (South Africa)

    Salami, O

    2009-09-01

    Full Text Available In inter-working multi-hop wireless networks, establishing resilient connectivity between source-destination node pairs is a major issue. The issue of connectivity in multi-hop wireless networks have been studied. However, these analyses focused...

  18. Sampling Practices and Social Spaces: Exploring a Hip-Hop Approach to Higher Education

    Science.gov (United States)

    Petchauer, Emery

    2010-01-01

    Much more than a musical genre, hip-hop culture exists as an animating force in the lives of many young adults. This article looks beyond the moral concerns often associated with rap music to explore how hip-hop as a larger set of expressions and practices implicates the educational experiences, activities, and approaches for students. The article…

  19. Contributions to the quality control of two crops of economic importance : hops and yerba mate

    NARCIS (Netherlands)

    Wilson, Erica Georgina

    2012-01-01

    Quality control of plants is essential and at the same time very challenging.In this thesis, studies involving quality issues of two plants used in the production of two popular beverages, hops (in beer) and Ilex paraguariensis (yerba mate) were undertaken. Hops are used as bittering agents and to

  20. Hip-Hop and a Hybrid Text in a Postsecondary English Class

    Science.gov (United States)

    Sanchez, Deborah M.

    2010-01-01

    This study explores the epistemology present in hip-hop music and its reflection in the writing of one African American student in a postsecondary transitional English class. An integration of hip-hop and academic literacy practices in the student's essay challenges the supremacy of a "standard" academic English and deficit perspectives about…

  1. Effect of storage on the brewing properties of tropical hop substitutes

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... conventional hops stored at 25oC for 30 weeks (12-17%) by Marr (1985) and Laws (1983). The reduction in the soft resin content of hops is a common phenomenon which is associated with the oxidative depreciation of the soft resins to hard resins with storage, Hough (1980). However, the low percentage ...

  2. Affiliation and Alienation: Hip-Hop, Rap, and Urban Science Education

    Science.gov (United States)

    Emdin, Christopher

    2010-01-01

    The critiques of rap artists and other participants in hip-hop culture provide data for teachers and researchers to investigate the attitudes of US urban youth towards schooling. This study explores the complex relationships between hip-hop and science education by examining how rap lyrics project beliefs about schooling, the relevance of existing…

  3. Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop).

    Science.gov (United States)

    Gitau, Grace W; Mandal, Pradipta; Blatch, Gregory L; Przyborski, Jude; Shonhai, Addmore

    2012-03-01

    Malaria is caused by Plasmodium species, whose transmission to vertebrate hosts is facilitated by mosquito vectors. The transition from the cold blooded mosquito vector to the host represents physiological stress to the parasite, and additionally malaria blood stage infection is characterised by intense fever periods. In recent years, it has become clear that heat shock proteins play an essential role during the parasite's life cycle. Plasmodium falciparum expresses two prominent heat shock proteins: heat shock protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90). Both of these proteins have been implicated in the development and pathogenesis of malaria. In eukaryotes, Hsp70 and Hsp90 proteins are functionally linked by an essential adaptor protein known as the Hsp70-Hsp90 organising protein (Hop). In this study, recombinant P. falciparum Hop (PfHop) was heterologously produced in E. coli and purified by nickel affinity chromatography. Using specific anti-PfHop antisera, the expression and localisation of PfHop in P. falciparum was investigated. PfHop was shown to co-localise with PfHsp70 and PfHsp90 in parasites at the trophozoite stage. Gel filtration and co-immunoprecipitation experiments suggested that PfHop was present in a complex together with PfHsp70 and PfHsp90. The association of PfHop with both PfHsp70 and PfHsp90 suggests that this protein may mediate the functional interaction between the two chaperones.

  4. Hegemony, Hope, and the Harlem Renaissance: Taking Hip Hop Culture Seriously

    Science.gov (United States)

    Price, Robert J., Jr.

    2005-01-01

    Adult education instructors and administrators, who typically are not members of the hip hop generation, often have little knowledge and understanding of rap music (also known as gangsta rap) and hip hop culture, and consequently do not take the black popular cultural phenomenon seriously as it relates to adult education. Adult educators,…

  5. Role of next-nearest-neighbour hopping in the internal structure of ...

    Indian Academy of Sciences (India)

    The thermodynamic properties such as entropy and specific heat are studied as functions of temperature with various NNN hopping strength. Results show that with the inclusion of negative NNN hopping, the system becomes more ordered. A qualitative transition temperature region has been estimated. It is shown that with ...

  6. Connectivity model for Inter-working multi-hop wireless networks

    CSIR Research Space (South Africa)

    Salami, O

    2009-08-01

    Full Text Available In Inter-working multi-hop wireless networks, establishing resilient connectivity between source-destination node pairs is a major issue. The issues of connectivity in Multi-hop wireless networks have been studied. However, these analyses focused...

  7. Don't Believe the Hype: Hip-Hop Literacies and English Education

    Science.gov (United States)

    Belle, Crystal

    2016-01-01

    Current scholarship suggests that many youths identify with hip-hop, especially youths of color. Study of this artistic form has been suggested as a means of helping youths acquire and become fluent in literacy practices. This article explores how the use of a hip-hop literacies curriculum addressed the literacy skills of urban ninth-grade English…

  8. Polish Hip Hop as a Form of Multiliteracies and Situated Learning

    Science.gov (United States)

    Torrence, Michael L.

    2009-01-01

    The purpose of this ethnographic study was to examine Hip Hop in Poland through the lens of multiliteracies and situated learning. This analysis is concerned with the transmission of Hip Hop to and within Wroclaw, Poland, and its acculturation and assimilation in Wroclaw, Poland. Further, this study seeks to illustrate how professional Polish Hip…

  9. Student Perceptions of the Hip Hop Culture's Influence on the Undergraduate Experience

    Science.gov (United States)

    Wessel, Roger D.; Wallaert, Kerry A.

    2011-01-01

    This study sought to determine how identification and engagement with the hip hop culture influenced the educational experiences of undergraduate students at a Midwestern, predominately White university by interviewing 11 students who self-identified as being immersed in the hip hop culture. Through a qualitative, phenomenological investigation,…

  10. Supporting Communication and Argumentation in Urban Science Education: Hip-Hop, the Battle, and the Cypher

    Science.gov (United States)

    Emdin, Christopher

    2011-01-01

    This paper is based on an exploration of communication and argumentation in urban science classrooms, and provides a description of the role that Hip-hop based education plays in supporting these major components of science education. The paper is intended to both support, and critique conventional uses of hip-hop based education, and provide…

  11. Representin': Drawing from Hip-Hop and Urban Youth Culture to Inform Teacher Education

    Science.gov (United States)

    Irizarry, Jason G.

    2009-01-01

    The potential of drawing from urban youth culture, and hip-hop more specifically, to serve as a bridge to the standard curriculum has been well documented. However, the richness and potential benefits of hip-hop are more far-reaching and present significant implications for teacher education and professional development efforts as well. This…

  12. Hip-Hop's Influence on the Identity Development of Black Female College Students: A Literature Review

    Science.gov (United States)

    Henry, Wilma J.; West, Nicole M.; Jackson, Andrea

    2010-01-01

    This article explores unique issues regarding the effects of hip-hop culture on the identity development of young Black female college students. Through the lenses of womanist and Black feminist perspectives, the intersecting impact of race and gender are reviewed within the context of the competing influences of hip-hop on Black female identity.…

  13. Deal with It We Must: Education, Social Justice, and the Curriculum of Hip Hop Culture

    Science.gov (United States)

    Baszile, Denise Taliaferro

    2009-01-01

    Although hip hop culture has been one of the most significant urban youth movements over the last three decades, it has only recently gained attention within the educational literature as a force to be reckoned with. And even then, much of the literature seeks to understand how hip hop can be used to engage students in the official school…

  14. Hip-Hop Culture in College Students' Lives: Elements, Embodiment, and Higher Edutainment

    Science.gov (United States)

    Petchauer, Emery

    2011-01-01

    College campuses have become rich sites of hip-hop culture and knowledge production. Despite the attention that campus personnel and researchers have paid to student life, the field of higher education has often misunderstood the ways that hip-hop culture exists in college students' lives. Based upon in-depth interviews, observations of…

  15. Hip-Hop, Social Justice, and Environmental Education: Toward a Critical Ecological Literacy

    Science.gov (United States)

    Cermak, Michael J.

    2012-01-01

    This essay describes an educational initiative that used environmentally themed (green) hip-hop to stimulate learning in an environmental science classroom. Students were then challenged to compose their own green hip-hop and their lyrics demonstrated skills that have thematic consistency around what is called a Critical Ecological Literacy (CEL).…

  16. HOP/NECC1, a novel regulator of mouse trophoblast differentiation.

    Science.gov (United States)

    Asanoma, Kazuo; Kato, Hidenori; Yamaguchi, Shinichiro; Shin, Chong Hyun; Liu, Zhi-Ping; Kato, Kiyoko; Inoue, Takafumi; Miyanari, Yoko; Yoshikawa, Koji; Sonoda, Kenzo; Fukushima, Kotaro; Wake, Norio

    2007-08-17

    Homeodomain-only protein/not expressed in choriocarcinoma clone 1 (HOP/NECC1) is a newly identified gene that modifies the expression of cardiac-specific genes and thereby regulates heart development. More recently, HOP/NECC1 was reported to be a suppressor of choriocarcinogenesis. Here, we examined the temporal expression profile of HOP/NECC1 in wild-type mouse placenta. We found that E8.5-E9.5 wild-type placenta expressed HOP/NECC1 in the giant cell and spongiotrophoblast layers. HOP/NECC1 (-/-) placenta exhibited marked propagation of giant cell layers and, in turn reduction of spongiotrophoblast formation. We demonstrated SRF transcriptional activity increased in the differentiating trophoblasts and forced expression of SRF in a trophoblast stem (TS) cell line induces the differentiation into giant cells. Negative regulation of SRF (serum response factor) by the binding of HOP/NECC1 protein contributed at least in part to the generation of these placental defects. Gradual induction of HOP/NECC1 in response to differentiation stimuli may result in the decision to differentiate into a particular type of trophoblastic cell lineage and result in non-lethal defects shown by the HOP/NECC1 (-/-) placentas.

  17. Expression of HopAI interferes with MAP kinase signalling in Magnaporthe oryzae.

    Science.gov (United States)

    Zhang, Xue; Liu, Wende; Li, Yang; Li, Guotian; Xu, Jin-Rong

    2017-10-01

    The Pmk1 and Mps1 MAP kinases are essential for appressorium formation and plant infection in Magnaporthe oryzae. However, their exact roles during invasive growth are not clear because pmk1 and mps1 mutants are defective in penetration. To further characterize their functions after penetration, in this study we expressed the Pseudomonas syringae effector HopAI known to inactivate plant MAP kinases in M. oryzae. Constitutive expression of HopAI with the RP27 or TrpC promoter resulted in defects in hyphal growth, conidiation, appressorium penetration and pathogenicity, which is similar to the phenotype of the mps1 mutant. HopAI interacted strongly with Mps1 in vivo and expression of dominant active MKK2 partially suppressed the defects of PRP27 -HopAI transformants, which were significantly reduced in Mps1 phosphorylation. When the infection-specific MIR1 (Magnaporthe-infection-related gene-1) promoter was used to express HopAI, PMIR1 -HopAI transformants were defective in the spreading of invasive hyphae and elicited strong defense responses in penetrated plant cells. Expression of HopAI in Fusarium graminearum also mainly affected the activation of Mgv1, an Mps1 orthologue. Taken together, our results showed that Mps1 is the major intracellular target of HopAI when it is overexpressed, and MAP kinase signalling is important for cell-to-cell movement of invasive hyphae in M. oryzae. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. We Got Next: Hip-Hop Pedagogy and the Next Generation of Democratic Education

    Science.gov (United States)

    Dando, Michael

    2017-01-01

    Using daily experiences and existing identities as the subject matter, a hip-hop-centered class encourages students to develop a critical lens so that they can "envision a social order which supports their full humanity" (Shor, 1987, p. 48) and embraces the idea that hip-hop culture provides context for students to develop critical…

  19. Empowerment in Context: Lessons from Hip-Hop Culture for Social Work Practice

    Science.gov (United States)

    Travis, Raphael, Jr.; Deepak, Anne

    2011-01-01

    Hip-hop culture can be used as a conduit to enhanced cultural competence and practice skills through the individual and community empowerment framework. This framework is introduced as a tool for direct practice that allows social workers to understand the competing messages within hip-hop culture and how they may impact youths by promoting or…

  20. Evaluating the Impact of Transmission Power on Selecting Tall Vehicles as Best Next Communication Hop

    NARCIS (Netherlands)

    Qiao, Yu; Klein Wolterink, W.; Karagiannis, Georgios; Heijenk, Geert

    The relatively low height of antennas on communicating vehicles in Vehicular Ad Hoc Networks (VANETs) makes one hop and as well multi-hop Vehicle-to-Vehicle (V2V) communication susceptible to obstruction by other vehicles on the road. When the transmitter or receiver (or both) is a Tall vehi- cle,

  1. Proust, Hip-Hop, and Death in First-Year Composition

    Science.gov (United States)

    Sirc, Geoffrey

    2006-01-01

    Hip-hop as content in a first-year writing course offers students a powerful way to connect with their worlds. This article draws on Marcel Proust as a kind of rhyme to legitimate hip-hop as a substantive expressive medium to achieve artistry in writing.

  2. Least Limiting Water Range and Load Bearing Capacity of Soil under Types of Tractor-Trailers for Mechanical Harvesting of Green Sugarcane

    Directory of Open Access Journals (Sweden)

    Antonio Higino Frederico Pereira

    2015-12-01

    Full Text Available ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (T1; harvester with two trailers with a capacity of 10 Mg each (T2; harvester with trailer with a capacity of 20 Mg (T3 and harvester and truck with trailer with a capacity of 20 Mg (10 Mg per compartment (T4. The least limiting water range and soil bearing capacity were evaluated. The transport equipment to remove the harvested sugarcane from the field (trailer at harvest decreased the least limiting water range, reducing the structural soil quality. The truck trailer caused the greatest impact on the soil physical properties studied. The soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (T1 exceeded the pre-consolidation pressure of the soil.

  3. Matured Hop Bittering Components Induce Thermogenesis in Brown Adipose Tissue via Sympathetic Nerve Activity.

    Directory of Open Access Journals (Sweden)

    Yumie Morimoto-Kobayashi

    Full Text Available Obesity is the principal symptom of metabolic syndrome, which refers to a group of risk factors that increase the likelihood of atherosclerosis. In recent decades there has been a sharp rise in the incidence of obesity throughout the developed world. Iso-α-acids, the bitter compounds derived from hops in beer, have been shown to prevent diet-induced obesity by increasing lipid oxidation in the liver and inhibition of lipid absorption from the intestine. Whereas the sharp bitterness induced by effective dose of iso-α-acids precludes their acceptance as a nutrient, matured hop bittering components (MHB appear to be more agreeable. Therefore, we tested MHB for an effect on ameliorating diet-induced body fat accumulation in rodents. MHB ingestion had a beneficial effect but, compared to iso-α-acids and despite containing structurally similar compounds, acted via different mechanisms to reduce body fat accumulation. MHB supplementation significantly reduced body weight gain, epididymal white adipose tissue weight, and plasma non-esterified free fatty acid levels in diet-induced obese mice. We also found that uncoupling protein 1 (UCP1 expression in brown adipose tissue (BAT was significantly increased in MHB-fed mice at both the mRNA and protein levels. In addition, MHB administration in rats induced the β-adrenergic signaling cascade, which is related to cAMP accumulation in BAT, suggesting that MHB could modulate sympathetic nerve activity innervating BAT (BAT-SNA. Indeed, single oral administration of MHB elevated BAT-SNA in rats, and this elevation was dissipated by subdiaphragmatic vagotomy. Single oral administration of MHB maintained BAT temperature at a significantly higher level than in control rats. Taken together, these findings indicate that MHB ameliorates diet-induced body fat accumulation, at least partly, by enhancing thermogenesis in BAT via BAT-SNA activation. Our data suggests that MHB is a useful tool for developing functional

  4. iHOPerator: user-scripting a personalized bioinformatics Web, starting with the iHOP website

    Directory of Open Access Journals (Sweden)

    Wilkinson Mark D

    2006-12-01

    Full Text Available Abstract Background User-scripts are programs stored in Web browsers that can manipulate the content of websites prior to display in the browser. They provide a novel mechanism by which users can conveniently gain increased control over the content and the display of the information presented to them on the Web. As the Web is the primary medium by which scientists retrieve biological information, any improvements in the mechanisms that govern the utility or accessibility of this information may have profound effects. GreaseMonkey is a Mozilla Firefox extension that facilitates the development and deployment of user-scripts for the Firefox web-browser. We utilize this to enhance the content and the presentation of the iHOP (information Hyperlinked Over Proteins website. Results The iHOPerator is a GreaseMonkey user-script that augments the gene-centred pages on iHOP by providing a compact, configurable visualization of the defining information for each gene and by enabling additional data, such as biochemical pathway diagrams, to be collected automatically from third party resources and displayed in the same browsing context. Conclusion This open-source script provides an extension to the iHOP website, demonstrating how user-scripts can personalize and enhance the Web browsing experience in a relevant biological setting. The novel, user-driven controls over the content and the display of Web resources made possible by user-scripts, such as the iHOPerator, herald the beginning of a transition from a resource-centric to a user-centric Web experience. We believe that this transition is a necessary step in the development of Web technology that will eventually result in profound improvements in the way life scientists interact with information.

  5. Hip-Hop as a Resource for Understanding the Urban Context: A Review of Christopher Edmin's--Science Education for the Hip-Hop Generation, Sense Publishers, Rotterdam, 2010

    Science.gov (United States)

    Brown, Bryan

    2010-01-01

    This review explores Edmin's "Science education for the hip-hop generation" by documenting how he frames hip-hop as a means to access urban student culture. He argues that hip-hop is more than a mere music genre, but rather a culture that provides young people with ways of connecting to the world. Two primary ideas emerged as central to…

  6. Throw Yo' Voice Out: Disability as a Desirable Practice in Hip-Hop Vocal Performance

    Directory of Open Access Journals (Sweden)

    Alex S. Porco

    2014-12-01

    Full Text Available Disabled bodies and disabling spaces— especially the recording studio— shape the sound iconicity of hip-hop vocal performances. The disabled voice is the audible sign by which hip-hop artists trouble cultural definitions of the self and other; exceptionalism and failure; the natural and techno-mediated; comedy and tragedy; and aesthetic play and seriousness. Hip-hop vocal performances also function as self-conscious acts of transvaluation that challenge the discursive dominance of ableism. A materialist approach to vocal performance resists reducing voice to a silent metaphor for race, oppositionality, or liberation; and it emphasizes, instead, the physiological and social processes that render hip-hop voices unique, particular, and audible. It emphasizes the agency hip-hop artists possess in seeking out disabled bodies and assuming disabled identities for aesthetic and political ends. Thus, the body is returned to the analysis of style.

  7. Compressive mechanical compatibility of anisotropic porous Ti6Al4V alloys in the range of physiological strain rate for cortical bone implant applications.

    Science.gov (United States)

    Li, Fuping; Li, Jinshan; Kou, Hongchao; Huang, Tingting; Zhou, Lian

    2015-09-01

    Porous titanium and its alloys are believed to be promising materials for bone implant applications, since they can reduce the "stress shielding" effect by tailoring porosity and improve fixation of implant through bone ingrowth. In the present work, porous Ti6Al4V alloys for biomedical application were fabricated by diffusion bonding of alloy meshes. Compressive mechanical behavior and compatibility in the range of physiological strain rate were studied under quasi-static and dynamic conditions. The results show that porous Ti6Al4V alloys possess anisotropic structure with elongated pores in the out-of-plane direction. For porous Ti6Al4V alloys with 60-70 % porosity, more than 40 % pores are in the range of 200-500 μm which is the optimum pore size suited for bone ingrowth. Quasi-static Young's modulus and yield stress of porous Ti6Al4V alloys with 30-70 % relative density are in the range of 6-40 GPa and 100-500 MPa, respectively. Quasi-static compressive properties can be quantitatively tailored by porosity to match those of cortical bone. Strain rate sensitivity of porous Ti6Al4V alloys is related to porosity. Porous Ti6Al4V alloys with porosity higher than 50 % show enhanced strain rate sensitivity, which is originated from that of base materials and micro-inertia effect. Porous Ti6Al4V alloys with 60-70 % porosity show superior compressive mechanical compatibility in the range of physiological strain rate for cortical bone implant applications.

  8. Complex Personhood of Hip Hop & the Sensibilities of the Culture That Fosters Knowledge of Self & Self-Determination

    Science.gov (United States)

    Love, Bettina L.

    2016-01-01

    Hip hop music and culture have a complex identity in that hip hop is based in self-determination, resistance, and the long enduring fight for Black freedom, but was also created alongside the seductiveness of the material and psychological conditions of capitalism, sexism, and patriarchy. Hip hop pedagogy (HHP) as a pedagogical framework is…

  9. Bringing Back Sweet (and Not so Sweet) Memories: The Cultural Politics of Memory, Hip-Hop, and Generational Identities

    Science.gov (United States)

    Hill, Marc Lamont

    2009-01-01

    This article examines the salience of collective "memory" and "remembering" among a group of students in Hip-Hop Lit, a hip-hop centered English literature course that I co-taught at "Howard High School," an urban high school in the Northeastern United States. Specifically, this article examines the memory work that occurred within Hip-Hop Lit in…

  10. RNAi knockdown of Hop (Hsp70/Hsp90 organising protein) decreases invasion via MMP-2 down regulation.

    LENUS (Irish Health Repository)

    Walsh, Naomi

    2011-07-28

    We previously identified Hop as over expressed in invasive pancreatic cancer cell lines and malignant tissues of pancreatic cancer patients, suggesting an important role for Hop in the biology of invasive pancreatic cancer. Hop is a co-chaperone protein that binds to both Hsp70\\/Hsp90. We hypothesised that by targeting Hop, signalling pathways modulating invasion and client protein stabilisation involving Hsp90-dependent complexes may be altered. In this study, we show that Hop knockdown by small interfering (si)RNA reduces the invasion of pancreatic cancer cells, resulting in decreased expression of the downstream target gene, matrix metalloproteinases-2 (MMP-2). Hop in conditioned media co-immunoprecipitates with MMP-2, implicating a possible extracellular function for Hop. Knockdown of Hop expression also reduced expression levels of Hsp90 client proteins, HER2, Bcr-Abl, c-MET and v-Src. Furthermore, Hop is strongly expressed in high grade PanINs compared to lower PanIN grades, displaying differential localisation in invasive ductal pancreatic cancer, indicating that the localisation of Hop is an important factor in pancreatic tumours. Our data suggests that the attenuation of Hop expression inactivates key signal transduction proteins which may decrease the invasiveness of pancreatic cancer cells possibly through the modulation of Hsp90 activity. Therefore, targeting Hop in pancreatic cancer may constitute a viable strategy for targeted cancer therapy.

  11. Engaging Black Males on Their Own Terms: What Schools Can Learn from Black Males Who Produce Hip-Hop

    Science.gov (United States)

    Irby, Decoteau J.; Petchauer, Emery; Kirkland, David

    2013-01-01

    Education scholars and practitioners have much to learn about engagement and motivation of Black males by directing their inquiries to more organic sites of hip-hop cultural production outside of schools. One such site is the hip-hop's informal labor economy where Black males engage in earning money through hip-hop cultural production. Labor…

  12. Conducting mechanisms of forming-free TiW/Cu{sub 2}O/Cu memristive devices

    Energy Technology Data Exchange (ETDEWEB)

    Yan, P.; Li, Y.; Hui, Y. J.; Zhong, S. J.; Zhou, Y. X.; Xu, L.; Liu, N.; Qian, H.; Sun, H. J., E-mail: shj@mail.hust.edu.cn; Miao, X. S. [Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-08-24

    P-type Cu{sub 2}O is a promising CMOS-compatible candidate to fabricate memristive devices for next-generation memory, logic and neuromorphic computing. In this letter, the microscopic switching and conducting mechanisms in TiW/Cu{sub 2}O/Cu memristive devices have been thoroughly investigated. The bipolar resistive switching behaviors without an electro-forming process are ascribed to the formation and rupture of the conducting filaments composed of copper vacancies. In the low resistive state, the transport of electrons in the filaments follows Mott's variable range hopping theory. When the devices switch back to high resistive state, the coexistence of Schottky emission at the Cu/Cu{sub 2}O interface and electron hopping between the residual filaments is found to dominate the conducting process. Our results will contribute to the further understanding and optimization of p-type memristive materials.

  13. Broadly tunable mode-hop-free mid-infrared light source with MgO:PPLN continuous-wave optical parametric oscillator.

    Science.gov (United States)

    Hong, Xiaoping; Shen, Xinglai; Gong, Mali; Wang, Feng

    2012-12-01

    We report a continuous-wave, broadly tunable mid-infrared MgO:PPLN optical parametric oscillator pumped by a fiber amplifier. Using pump tuning with synchronized temperature optimization, we achieve the broadest mode-hop-free (MHF) tuning of idler light over 30 cm(-1). We further use this tunable mid-infrared laser to demonstrate high-resolution absorption spectroscopy of methane across the MHF tuning range.

  14. Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range

    Science.gov (United States)

    2013-01-01

    Background Citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of Xanthomonas. X. citri subsp. citri strain 306 (XccA306) is a type A (Asiatic) strain with a wide host range, whereas its variant X. citri subsp. citri strain Aw12879 (Xcaw12879, Wellington strain) is restricted to Mexican lime. Results To characterize the mechanism for the differences in host range of XccA and Xcaw, the genome of Xcaw12879 that was completed recently was compared with XccA306 genome. Effectors xopAF and avrGf1 are present in Xcaw12879, but were absent in XccA306. AvrGf1 was shown previously for Xcaw to cause hypersensitive response in Duncan grapefruit. Mutation analysis of xopAF indicates that the gene contributes to Xcaw growth in Mexican lime but does not contribute to the limited host range of Xcaw. RNA-Seq analysis was conducted to compare the expression profiles of Xcaw12879 and XccA306 in Nutrient Broth (NB) medium and XVM2 medium, which induces hrp gene expression. Two hundred ninety two and 281 genes showed differential expression in XVM2 compared to in NB for XccA306 and Xcaw12879, respectively. Twenty-five type 3 secretion system genes were up-regulated in XVM2 for both XccA and Xcaw. Among the 4,370 common genes of Xcaw12879 compared to XccA306, 603 genes in NB and 450 genes in XVM2 conditions were differentially regulated. Xcaw12879 showed higher protease activity than XccA306 whereas Xcaw12879 showed lower pectate lyase activity in comparison to XccA306. Conclusions Comparative genomic analysis of XccA306 and Xcaw12879 identified strain specific genes. Our study indicated that AvrGf1 contributes to the host range limitation of Xcaw12879 whereas XopAF contributes to virulence. Transcriptome analyses of XccA306 and Xcaw12879 presented insights into the expression of the two closely related strains of X. citri subsp. citri. Virulence genes including genes encoding T3SS components

  15. Nonregenerative Dual-Hop Cooperative Links with Selection Diversity

    Directory of Open Access Journals (Sweden)

    Karagiannidis George K

    2006-01-01

    Full Text Available The end-to-end performance of dual-hop cooperative diversity systems equipped with nonregenerative relays and a selection combining receiver at the destination terminal over independent and nonidentical Nakagami- fading channels is studied. Closed-form expressions for the cumulative distribution function and the probability density function of the end-to-end signal-to-noise ratio ( are presented, while analytical formulae are derived for the moments and the moment generating function. Using these statistical results, closed-form expressions for the outage probability are presented for both channel state information and fixed gain relays. Furthermore, for the case of fixed gain relay, the average end-to-end , the amount of fading, and the average bit error rate can be numerically evaluated. The proposed mathematical analysis is complemented by numerical examples, including the effects on the overall performance of the s unbalancing as well as the fading severity.

  16. SDN-Based Double Hopping Communication against Sniffer Attack

    Directory of Open Access Journals (Sweden)

    Zheng Zhao

    2016-01-01

    Full Text Available Sniffer attack has been a severe threat to network communication security. Traditional network usually uses static network configuration, which provides convenience to sniffer attack. In this paper, an SDN-based double hopping communication (DHC approach is proposed to solve this problem. In DHC, ends in communication packets as well as the routing paths are changed dynamically. Therefore, the traffic will be distributed to multiple flows and transmitted along different paths. Moreover, the data from multiple users will be mixed, bringing difficulty for attackers in obtaining and recovering the communication data, so that sniffer attack will be prevented effectively. It is concluded that DHC is able to increase the overhead of sniffer attack, as well as the difficulty of communication data recovery.

  17. Systematic network coding for two-hop lossy transmissions

    Science.gov (United States)

    Li, Ye; Blostein, Steven; Chan, Wai-Yip

    2015-12-01

    In this paper, we consider network transmissions over a single or multiple parallel two-hop lossy paths. These scenarios occur in applications such as sensor networks or WiFi offloading. Random linear network coding (RLNC), where previously received packets are re-encoded at intermediate nodes and forwarded, is known to be a capacity-achieving approach for these networks. However, a major drawback of RLNC is its high encoding and decoding complexity. In this work, a systematic network coding method is proposed. We show through both analysis and simulation that the proposed method achieves higher end-to-end rate as well as lower computational cost than RLNC for finite field sizes and finite-sized packet transmissions.

  18. Double-hop networks using VSATs for the Intelsat system

    Science.gov (United States)

    Mizuno, Toshio; Nohara, Mitsuo; Watanabe, Fumio; Takeuchi, Yoshio; Honda, Teruhiko

    The double-hop VSAT (very small aperture terminal) network was studied with emphasis on its feasibility and networking in the Intelsat system. The results of channel-capacity estimation indicate that reasonable channel capacity and availability objectives equal to those for Super IBS (Intelsat business services) are attainable through the use of the uplink and downlink power control incorporated in the outbound link with BPSK/SCPC (binary-phase shift keying/single channel per carrier) transmission. Possible network architectures for various beam configurations were devised, and the accessibility of individual network architectures was analyzed in terms of blocking probability and call setup time. Based on the results of architecture study, an example implementation of VSAT system is shown. Furthermore, experimental results on the developed VSAT system are discussed. The experiment showed that the transmit power control for the outbound SCPC carrier is conducive to meeting stringent performance objectives stipulated for international digital transmissions.

  19. Coupled catastrophes: sudden shifts cascade and hop among interdependent systems.

    Science.gov (United States)

    Brummitt, Charles D; Barnett, George; D'Souza, Raissa M

    2015-11-06

    An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behaviour in its normal form as fast-slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g. trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to 'hop' over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets. © 2015 The Authors.

  20. Mechanisms for control of biological electron transfer reactions.

    Science.gov (United States)

    Williamson, Heather R; Dow, Brian A; Davidson, Victor L

    2014-12-01

    Electron transfer (ET) through and between proteins is a fundamental biological process. The rates and mechanisms of these ET reactions are controlled by the proteins in which the redox centers that donate and accept electrons reside. The protein influences the magnitudes of the ET parameters, the electronic coupling and reorganization energy that are associated with the ET reaction. The protein can regulate the rates of the ET reaction by requiring reaction steps to optimize the system for ET, leading to kinetic mechanisms of gated or coupled ET. Amino acid residues in the segment of the protein through which long range ET occurs can also modulate the ET rate by serving as staging points for hopping mechanisms of ET. Specific examples are presented to illustrate these mechanisms by which proteins control rates of ET reactions. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Agronomic performance and beer quality assessment of twenty hop cultivars grown in Central Italy

    Directory of Open Access Journals (Sweden)

    Francesco Rossini

    2016-08-01

    Full Text Available Hop market and beer industry have always been of secondary relevance in Italy as compared to grape and wine sector. Hence, hop cultivars and the information for growing hops have been generated almost entirely from the major hop production countries. Identifying cultivars that perform well in Mediterranean environments is therefore essential to successfully start hop cultivation and breeding activity in this new growing region. To evaluate the intraspecific diversity of hop in Central Italy, 20 female hop genotypes with different origin were screened during three growing seasons (2013-2015 in an experimental hop yard. Cones yield, plant height and crop phenology were evaluated to determine which cultivars were best suited to the Mediterranean climate. Moreover, given the rising interest for the development of local beers with distinguishing aroma, a sensory analysis was performed and beers flavoured with locally produced and imported cones were compared. A significant diversity among cultivars was found for all parameters investigated. The results indicated that weather condition during flowering and development of cones markedly affected yield and plant height. Cones yield was negatively correlated with thermal time (r=–0.5, P<0.05 to harvest and positively with plant height (r=0.56, P<0.05. Cascade, Hallertauer Magnum, Hersbrucker Spat and Yeoman showed the best adaptability to the Mediterranean growing conditions as they were the top-performing cultivars across the three years. Sensory analysis evidenced the importance of cultivar selection as determining factor for flavouring properties of beers. In general, results showed that the origin of cones strongly affected the mouth feel of beers. More complex and appreciated aroma profiles were identified for beers flavoured with local cones than those hopped with commercial products.

  2. Effect of Drive Row Ground Covers on Hop (Rosales: Cannabaceae) Yard Arthropod Pests in Vermont, USA.

    Science.gov (United States)

    Calderwood, L; Cubins, J; Vesty, D; Darby, H

    2017-04-01

    Alternatives to pesticides are necessary for the management of hop (Humulus lupulus L.) arthropod pests. The three major arthropod pests in northeastern US hop production include two-spotted spider mite, Tetranychus urticae Koch, hop aphid Phorodon humuli (Schrank), and potato leafhopper, Empoasca fabae Harris. This 3-yr study (2012-2014) in Vermont investigated the effect of flowering ground covers on arthropod pest abundance. Hop cultivars 'Nugget' and 'Cascade' were evaluated under a strip-split plot experimental design. Ground cover treatments included 1) Control: mowed red clover (Trifolium pratense) and resident weeds, 2) Clover: red clover, and 3) Diverse: common yarrow (Achillea millefolium), beebalm (Monarda fistulosa), red clover, and annual sunflower (Helianthus annuus). Natural enemies were grouped by associated pest and indicated by our mixed model to be strong predictors of the number of hop aphid and potato leafhopper on hop plants. In year two, ground cover treatment had a significant effect on two-spotted spider mite abundance where fewer two-spotted spider mite were observed on hop plants in Diverse plots. The established, un-mowed Clover treatment was preferred by potato leafhopper over Diverse ground cover and hop plants. This revealed the potential for clover ground cover to serve as a trap crop for potato leafhopper management in northeastern hop yards. Our findings are evidence that ground covers implemented for conservation biological control may serve more specific pest management functions instead of or in addition to boosting top-down pest pressure. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Zero-valent aluminum for reductive removal of aqueous pollutants over a wide pH range: Performance and mechanism especially at near-neutral pH.

    Science.gov (United States)

    Yang, Shiying; Zheng, Di; Ren, Tengfei; Zhang, Yixuan; Xin, Jia

    2017-10-15

    Zero-valent aluminum (ZVAl) draws much attention due to its strong reducibility. However, under neutral pH conditions, the reduction ability of ZVAl for pollutant removal has still been suspected because of the formed compact surface film of Al-(hydr)oxide. In this study, unmodified ZVAl was employed to reductively remove aqueous pollutants over a wide pH range, and its performance and mechanism, especially at near-neutral pH, were systematically studied for the first time. Results demonstrated that ZVAl had a wide range of pH applicability from 2 to 12, even in neutral environment. Typical nitro compound nitrobenzene (NB), typical azo dye acid orange 7 (AO7), and typical inorganic heavy metal ion Cr(VI) can be effectively removed at initial pH 7. Based on the changes of pH, ORP, DO, Al ions and TOC of the reaction solution, and the determination of reduction products of NB by UV-Vis and GC-MS, we found that NB removal by ZVAl can be primarily attributed to the reduction role. NB was reduced to nitrosobenzene firstly, and to aniline finally. Meanwhile, the adsorption phenomenon existed in this system. Next, the surface reaction mechanism was deeply revealed through the characterization of ZVAl particles before and after reaction by SEM-EDS, TEM, HRTEM, XRD, and XPS. It was found that ZVAl powders with core/shell structure participated in the redox reaction, and that ZVAl core was corroded, generating Al-(hydr)oxide. ZVAl surface oxide film was not directly removed, instead of a rougher one. Finally, the proposed reductive mechanism of aqueous pollutants by ZVAl was speculated from the angle of electronic competition. In water environment, O2, H2O and pollutants, with a clear competitive relationship, can capture electrons released from ZVAl. When pollutant's opportunities for getting electrons are enhanced, efficiently reductive reactions for pollutant removal can take place, even at near-neutral pH. In a word, ZVAl is a promising material to remove aqueous

  4. Influence of constant current stress on the conduction mechanisms of reverse leakage current in UV-A light emitting diodes

    Science.gov (United States)

    Wang, Yingzhe; Zheng, Xuefeng; Dai, Feng; Zhu, Jiaduo; Li, Peixian; Ma, Xiaohua; Hao, Yue

    2017-12-01

    The influence of constant current stress on the conduction mechanism of reverse leakage current in ultraviolet (UV) light emitting diodes (LEDs) in the UV-A spectral range has been investigated for the first time using temperature-dependent current-voltage measurement from 370 K to 55 K. Below 220 K, variable range hopping mechanism dominates in UV-A LEDs. While, above 220 K, the leakage current is attributed to Poole-Frenkel emission mechanism within the bias range of -3 ∼ -6 V. With the increasing of the reverse bias, the conduction mechanism transforms from Poole-Frenkel emission to space-charge-limited conduction mechanism. In particular, applying electrical stress yields an alteration of the transition voltage from -7.5 V to -6.5 V. We propose that stress could lead to a reduction of the thermal activation energy, and therefore alters the transition voltage.

  5. Optimal Design of Dual-Hop VLC/RF Communication System With Energy Harvesting

    KAUST Repository

    Rakia, Tamer

    2016-07-28

    In this letter, we consider a dual-hop heterogeneous visible light communication (VLC)/radio frequency (RF) communication system to extend the coverage of VLC systems. Besides detecting the information over VLC link, the relay is able to harvest energy from the first-hop VLC link, by extracting the direct current component of the received optical signal, and uses the harvested energy to retransmit the data to a mobile terminal over the second-hop RF link. We investigate the optimal design of the hybrid system in terms of data rate maximization.

  6. High temperature electrical conductivity due to small polaron hopping motion in DNA molecules

    Energy Technology Data Exchange (ETDEWEB)

    Triberis, G P [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, 15784 Zografos, Athens (Greece); Karavolas, V C [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, 15784 Zografos, Athens (Greece); Simserides, C D [University of Athens, Physics Department, Solid State Section, Panepistimiopolis, 15784 Zografos, Athens (Greece); Leibniz Institute for Neurobiology, Special Lab for Non-Invasing Brain Imaging, Brenneckestr. 6, D-39118 Magdeburg (Germany)

    2005-01-01

    We present a small polaron hopping model to interpret the high-temperature electrical conductivity measured along the DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. The experimental data for the lambda phage DNA ({lambda}-DNA) and the poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behavior leading to realistic values of the maximum hopping distances supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbors of the DNA molecular 'wire'.

  7. Electrical conductivity mechanisms in zinc oxide thin films deposited by pulsed laser deposition using different growth environments

    Energy Technology Data Exchange (ETDEWEB)

    Heluani, S.P. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina)]. E-mail: sperez@herrera.unt.edu.ar; Braunstein, G. [Department of Physics, University of Central Florida, Orlando, FL 32816 (United States); Villafuerte, M. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina); Simonelli, G. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina); Duhalde, S. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina)

    2006-12-05

    The mechanisms of electrical conduction in zinc oxide thin films, grown by pulsed laser deposition, have been investigated as a function of preparation conditions. The films were deposited on glass and silicon nitride coated silicon, using oxygen rich, oxygen deficient, or nitrogen atmospheres. The substrates were held at 473 K during deposition, and subsequently cooled down to room temperature in oxygen rich atmosphere of 4 Pa, or oxygen deficient atmosphere of 2 x 10{sup -3} Pa. Films deposited and cooled in an oxygen deficient atmosphere exhibited very high donor concentration, originated in intrinsic defects, and an impurity band related mechanism of conduction. Films deposited under relatively high oxygen pressure were highly resistive and showed, upon ultraviolet light irradiation, grain boundary controlled electrical transport. An enhancement of the conductivity was observed when using a nitrogen atmosphere during the deposition, and oxygen atmosphere during cooling. In this case, the dependence of the conductivity with temperature followed Motts' Law of variable range hopping, characteristic of a material with localized states randomly located in space. Since the density of hopping centers appears to be much larger than the density of nitrogen incorporated in this sample, it is suggested that the nitrogen induces defects in the zinc oxide lattice that behave as localized hopping centers, as well as carrier suppliers, giving rise to the observed conductivity.

  8. Power distribution of a co-axial dual-mechanical-port flux-switching permanent magnet machine for fuel-based extended range electric vehicles

    Science.gov (United States)

    Zhou, Lingkang; Hua, Wei; Zhang, Gan

    2017-05-01

    In this paper, power distribution between the inner and outer machines of a co-axial dual-mechanical-port flux-switching permanent magnet (CADMP-FSPM) machine is investigated for fuel-based extended range electric vehicle (ER-EV). Firstly, the topology and operation principle of the CADMP-FSPM machine are introduced, which consist of an inner FSPM machine used for high-speed, an outer FSPM machine for low-speed, and a magnetic isolation ring between them. Then, the magnetic field coupling of the inner and outer FSPM machines is analyzed with more attention paid to the optimization of the isolation ring thickness. Thirdly, the power-dimension (PD) equations of the inner and outer FSPM machines are derived, respectively, and thereafter, the PD equation of the whole CADMP-FSPM machine can be given. Finally, the PD equations are validated by finite element analysis, which supplies the guidance on the design of this type of machines.

  9. Do we have a common mechanism for measuring time in the hundreds of millisecond range? Evidence from multiple-interval timing tasks.

    Science.gov (United States)

    Merchant, Hugo; Zarco, Wilbert; Prado, Luis

    2008-02-01

    In the present study we examined the performance variability of a group of 13 subjects in eight different tasks that involved the processing of temporal intervals in the subsecond range. These tasks differed in their sensorimotor processing (S; perception vs. production), the modality of the stimuli used to define the intervals (M; auditory vs. visual), and the number of intervals (N; one or four). Different analytical techniques were used to determine the existence of a central or distributed timing mechanism across tasks. The results showed a linear increase in performance variability as a function of the interval duration in all tasks. However, this compliance of the scalar property of interval timing was accompanied by a strong effect of S, N, and M and the interaction between these variables on the subjects' temporal accuracy. Thus the performance variability was larger not only in perceptual tasks than that in motor-timing tasks, but also using visual rather than auditory stimuli, and decreased as a function of the number of intervals. These results suggest the existence of a partially overlapping distributed mechanism underlying the ability to quantify time in different contexts.

  10. Concentration ranges of antibacterial cations for showing the highest antibacterial efficacy but the least cytotoxicity against mammalian cells: implications for a new antibacterial mechanism.

    Science.gov (United States)

    Ning, Chengyun; Wang, Xiaolan; Li, Lihua; Zhu, Ye; Li, Mei; Yu, Peng; Zhou, Lei; Zhou, Zhengnan; Chen, Junqi; Tan, Guoxin; Zhang, Yu; Wang, Yingjun; Mao, Chuanbin

    2015-09-21

    Antibacterial metal ions, such as Ag(+), Zn(2+) and Cu(2+), have been extensively used in medical implants and devices due to their strong broad spectrum of antibacterial activity. However, it is still a controversial issue as to whether they can show the desired antibacterial activity while being toxic to mammalian cells. It is very important to balance their antibacterial effectiveness with minimal damage to mammalian cells. Toward this end, this study is to identify the suitable concentrations of these three ions at which they can effectively kill two types of clinically relevant bacteria (Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)) but show no obvious cytotoxicity on fibroblasts. Such concentration ranges are found to be 2.5 × 10(-7) M-10(-6) M, 10(-5) M-10(-4) M, and 10(-5) M-10(-4) M for Ag(+), Zn(2+), and Cu(2+), respectively. Investigation of their antibacterial mechanism shows that these three metal ions all show antibacterial property through a mechanism of damaging bacterial cell membranes by the generation of reactive oxygen species but surprisingly preserving the integrity of bacterial genomic DNA. The encouraging results indicate that antibacterial metal ions with controlled concentrations can bring considerable benefits to biomedical applications.

  11. The effects of next-to-nearest-neighbour hopping on Bose–Einstein ...

    Indian Academy of Sciences (India)

    - to-nearest-neighbour boson hopping (t ) energy on Bose–Einstein condensation in cubic lattices. We consider both non-interacting and repulsively interacting bosons moving in the lowest Bloch band. The interacting bosons are studied using ...

  12. You know what it is: learning words through listening to hip-hop.

    Science.gov (United States)

    Chesley, Paula

    2011-01-01

    Music listeners have difficulty correctly understanding and remembering song lyrics. However, results from the present study support the hypothesis that young adults can learn African-American English (AAE) vocabulary from listening to hip-hop music. Non-African-American participants first gave free-response definitions to AAE vocabulary items, after which they answered demographic questions as well as questions addressing their social networks, their musical preferences, and their knowledge of popular culture. Results from the survey show a positive association between the number of hip-hop artists listened to and AAE comprehension vocabulary scores. Additionally, participants were more likely to know an AAE vocabulary item if the hip-hop artists they listen to use the word in their song lyrics. Together, these results suggest that young adults can acquire vocabulary through exposure to hip-hop music, a finding relevant for research on vocabulary acquisition, the construction of adolescent and adult identities, and the adoption of lexical innovations.

  13. Juventud y comunicacion: reflexiones sobre practicas comunicativas de resistencia en la cultura hip hop de Medellin

    National Research Council Canada - National Science Library

    Garces Montoya, Angela

    2011-01-01

    ... de la apropiacion de medios de comunicacion alternativos. En este articulo se reconocen los desarrollos comunicativos en portales web y estudios de grabacion, apropiados por las culturas juveniles, en especial el movimiento hip hop de Medellin...

  14. Research on Improved DV-HOP Algorithm against Wormhole Attacks in WSN

    Directory of Open Access Journals (Sweden)

    Wang Xue-Wen

    2016-01-01

    Full Text Available The secure location of node is significant in the WSN (Wireless Sensor Networks of the troop frontier defence system. The wormhole attack is a big threat in the secure location. The credibility of the beacon node was used to determine the malicious nodes produced by wormhole attack in the WSN. The estimated method of multibeacon nodes was adopted to improve DV-HOP algorithm after excluding the malicious nodes. In this paper, we compared the basic DV-HOP algorithm and the improved DV-HOP algorithm in the coverage percentage and the error of network localization by simulating. The simulation results indicate that the improved DV-HOP algorithm makes the localization coverage percentage can reach 90% on a certain scale of the network, and it makes the error percentage lower when the number of beacons is different.

  15. You Know What It Is: Learning Words through Listening to Hip-Hop: e28248

    National Research Council Canada - National Science Library

    Paula Chesley

    2011-01-01

    ..., their musical preferences, and their knowledge of popular culture. Results from the survey show a positive association between the number of hip-hop artists listened to and AAE comprehension vocabulary scores...

  16. You know what it is: learning words through listening to hip-hop

    National Research Council Canada - National Science Library

    Chesley, Paula

    2011-01-01

    ..., their musical preferences, and their knowledge of popular culture. Results from the survey show a positive association between the number of hip-hop artists listened to and AAE comprehension vocabulary scores...

  17. Hip external rotation strength predicts hop performance after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Kline, Paul W; Burnham, Jeremy; Yonz, Michael; Johnson, Darren; Ireland, Mary Lloyd; Noehren, Brian

    2017-04-04

    Quadriceps strength and single-leg hop performance are commonly evaluated prior to return to sport after anterior cruciate ligament reconstruction (ACLR). However, few studies have documented potential hip strength deficits after ACLR, or ascertained the relative contribution of quadriceps and hip strength to hop performance. Patients cleared for return to sports drills after ACLR were compared to a control group. Participants' peak isometric knee extension, hip abduction, hip extension, and hip external rotation (HER) strength were measured. Participants also performed single-leg hops, timed hops, triple hops, and crossover hops. Between-limb comparisons for the ACLR to control limb and the non-operative limb were made using independent two-sample and paired sample t tests. Pearson's correlations and stepwise multiple linear regression were used to determine the relationships and predictive ability of limb strength, graft type, sex, and limb dominance to hop performance. Sixty-five subjects, 20 ACLR [11F, age 22.8 (15-45) years, 8.3 ± 2 months post-op, mass 70.47 ± 12.95 kg, height 1.71 ± 0.08 m, Tegner 5.5 (3-9)] and 45 controls [22F, age 25.8 (15-45) years, mass 74.0 ± 15.2 kg, height 1.74 ± 0.1 m, Tegner 6 (3-7)], were tested. Knee extension (4.4 ± 1.5 vs 5.4 ± 1.8 N/kg, p = 0.02), HER (1.4 ± 0.4 vs 1.7 ± 0.5 N/kg, p = 0.04), single-leg hop (146 ± 37 vs 182 ± 38% limb length, p hop (417 ± 106 vs 519 ± 102% limb length, p hop (3.3 ± 2.0 vs 2.3 ± 0.6 s, p hop (364 ± 107 vs 446 ± 123% limb length, p = 0.01) were significantly impaired in the operative versus control subject limbs. Similar deficits existed between the operative and non-operative limbs. Knee extension and HER strength were significantly correlated with each of the hop tests, but only HER significantly predicted hop performance. After ACLR, patients have persistent HER strength, knee extension strength, and hop test deficits in the

  18. You know what it is: learning words through listening to hip-hop

    National Research Council Canada - National Science Library

    Chesley, Paula

    2011-01-01

    ...) vocabulary from listening to hip-hop music. Non-African-American participants first gave free-response definitions to AAE vocabulary items, after which they answered demographic questions as well as questions addressing their social networks...

  19. HOP/NECC1, A Novel Regulator of Mouse Trophoblast Differentiation

    National Research Council Canada - National Science Library

    Kazuo Asanoma; Hidenori Kato; Shinichiro Yamaguchi; Chong Hyun Shin; Zhi-Ping Liu; Kiyoko Kato; Takafumi Inoue; Yoko Miyanari; Koji Yoshikawa; Kenzo Sonoda; Kotaro Fukushima; Norio Wake

    2007-01-01

    Homeodomain-only protein/not expressed in choriocarcinoma clone 1 (HOP/NECC1) is a newly identified gene that modifies the expression of cardiac-specific genes and thereby regulates heart development...

  20. STUDY ON THE EVOLUTION OF THE HOP MARKET IN ROMANIA DURING THE PERIOD 2007-2014

    Directory of Open Access Journals (Sweden)

    Irina - Adriana CHIURCIU

    2015-06-01

    Full Text Available The aim of this article is to present the evolution of hop market during the period 2007-2014 in Romania. It is based on the statistical data provided by the National Institute of Statistics and by the Ministry of Agriculture and Rural Development. The indicators used for processing the data are the following: the total production, the cultivated areas of hop and the quantity of hop imported and exported. From the analysis of the results obtained we can observe a decrease of 69.51% in 2012 from the total production in comparison with 2007. In the last years of the period in study, from 2012 to 2014, it increased by 104.4%. However the inland production is insufficient for the local beer industry. Romania has to import vast amounts of hops to ensure the brewers requirements across the country.

  1. Hip hopping the gap--performing arts approaches to sexual health disadvantage in young people in remote settings.

    Science.gov (United States)

    Crouch, Alan; Robertson, Heather; Fagan, Patricia

    2011-07-01

    Closing the gap in Indigenous health and wellbeing in remote settings in the Torres Strait and Northern Peninsula Area of Far North Queensland (FNQ) includes addressing a well-documented sexual health disadvantage among young people. Community mobilization around the underlying risk factors influencing sexual health is required. Performing-arts-based workshops were conducted in schools and after-school venues in four remote Aboriginal and Torres Strait islander locations in FNQ in early 2010, to initiate consciousness-raising around the real dimensions of youth sexual health risk. Specific objectives included strengthening operational partnerships at school-level and developing ongoing consultative processes in each location for sexual health reference group development. Results include a significantly strengthened productive partnership with primary and high schools in each location and sixteen production-ready hip hop songs exploring a range of physical, emotional and sexual health themes authored by the students and recorded on site. Additional outcomes included the willingness of community councils and civil society organizations to support local sexual health reference group activity. This initiative, the Indigenous Hip Hop Project, although accompanied by opportunity costs including alternative, more core business uses of staff time and program budget, has demonstrated the power of tapping the creative energy of young people at risk and the potential for mobilizing communities to activism around sexual health disadvantage.

  2. Blind Compressed Sensing Parameter Estimation of Non-cooperative Frequency Hopping Signal

    OpenAIRE

    Chen Ying; Zhong Fei; Guo Shuxu

    2016-01-01

    To overcome the disadvantages of a non-cooperative frequency hopping communication system, such as a high sampling rate and inadequate prior information, parameter estimation based on Blind Compressed Sensing (BCS) is proposed. The signal is precisely reconstructed by the alternating iteration of sparse coding and basis updating, and the hopping frequencies are directly estimated based on the results. Compared with conventional compressive sensing, blind compressed sensing does not require pr...

  3. Electron Tunneling and Hopping Possibilites in RuO2 Thick Films

    OpenAIRE

    Halder, N. C.

    1983-01-01

    It is proposed in this paper that the temperature coefficient of resistivity (TCR) in thick film resistors arises from (i) the usual particle-to-particle conduction, (ii) electron tunneling, and (iii) the phononassisted hopping. Equations for activation energies are derived for the temperature minimum of the resistance with and without hopping. New equations for TCR are suggested. Some extensive calculations of TCR and activation energy have been made for RuO2 thick film resistors, the result...

  4. Study of one-dimensional electron hopping and its effects on ESR line shape

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jau [Argonne National Lab., IL (United States); Dikshit, S.N. [Univ. of Chicago, IL (United States). Dept. of Chemistry; Norris, J.R. [Argonne National Lab., IL (United States)]|[Univ. of Chicago, IL (United States). Dept. of Chemistry

    1997-08-01

    Random hopping processes between discrete sites along a finite open chain or around a closed finite loop are examined. Closed form formulae are prescribed for the dependence of the ESR (electron spin resonance) line shape on the chain length and hopping rate. Significant differences between the closed loop and open chain are demonstrated. Deviation at short time from the results of diffusion in a continuum is presented.

  5. Measurement and Analysis of Single-Hop Delay on an IP Backbone Network

    OpenAIRE

    Papagiannaki, Konstantina; Moon, Sue; Fraleigh, Chuck; Thiran, Patrick; Diot, Christophe

    2003-01-01

    We measure and analyze the single-hop packet delay through operational routers in the Sprint Internet protocol (IP) backbone network. After presenting our delay measurements through a single router for OC-3 and OC-12 link speeds, we propose a methodology to identify the factors contributing to single-hop delay. In addition to packet processing, transmission, and queueing delay at the output link, we observe the presence of very large delays that cannot be explained within the context of a fir...

  6. Age-related muscle activation profiles and joint stiffness regulation in repetitive hopping

    OpenAIRE

    Hoffrén, Merja; Ishikawa, Masaki; Rantalainen, Timo; Avela, Janne; Komi, Paavo

    2011-01-01

    It is well documented that increasing effort during exercise is characterized by an increase in electromyographic activity of the relevant muscles. How aging influences this relationship is a matter of great interest. In the present study, nine young and 24 elderly subjects did repetitive hopping with maximal effort as well as with 50%, 65%, 75% and 90% intensities. During hopping joint kinematics were measured together with electromyographic activity (EMG) from the soleus, gastrocnemius medi...

  7. Effective one-dimensionality of universal ac hopping conduction in the extreme disorder limit

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Schrøder, Thomas

    1996-01-01

    A phenomenological picture of ac hopping in the symmetric hopping model (regular lattice, equal site energies, random energy barriers) is proposed according to which conduction in the extreme disorder limit is dominated by essentially one-dimensional "percolation paths." Modeling a percolation pa...... as strictly one dimensional with a sharp jump rate cutoff leads to an expression for the universal ac conductivity that fits computer simulations in two and three dimensions better than the effective medium approximation....

  8. Development of aromatic hop compounds and bitterness in beer during room temperature- and cold storage based on three different hopping methods

    OpenAIRE

    Torgals, Ann Elisabeth

    2015-01-01

    The main objective of this study was to determine whether storage temperature or hopping method had influence on the aroma and bitterness in beer. The focus was set on the aroma that comes from hops, and not from yeast. The secondary objective to this study was to explore the development of the alcohol, CO2 and bitterness in the beer after priming and bottling. The thesis’ main perspective is that of home brewers, and to some extent that of microbreweries. Beer was brewed with 100 % pilsn...

  9. Solution structure and DNA-binding properties of the winged helix domain of the meiotic recombination HOP2 protein.

    Science.gov (United States)

    Moktan, Hem; Guiraldelli, Michel F; Eyster, Craig A; Zhao, Weixing; Lee, Chih-Ying; Mather, Timothy; Camerini-Otero, R Daniel; Sung, Patrick; Zhou, Donghua H; Pezza, Roberto J

    2014-05-23

    The HOP2 protein is required for efficient double-strand break repair which ensures the proper synapsis of homologous chromosomes and normal meiotic progression. We previously showed that in vitro HOP2 shows two distinctive activities: when it is incorporated into a HOP2-MND1 heterodimer, it stimulates DMC1 and RAD51 recombination activities, and the purified HOP2 alone is proficient in promoting strand invasion. The structural and biochemical basis of HOP2 action in recombination are poorly understood; therefore, they are the focus of this work. Herein, we present the solution structure of the amino-terminal portion of mouse HOP2, which contains a typical winged helix DNA-binding domain. Together with NMR spectral changes in the presence of double-stranded DNA, protein docking on DNA, and mutation analysis to identify the amino acids involved in DNA coordination, our results on the three-dimensional structure of HOP2 provide key information on the fundamental structural and biochemical requirements directing the interaction of HOP2 with DNA. These results, in combination with mutational experiments showing the role of a coiled-coil structural feature involved in HOP2 self-association, allow us to explain important aspects of the function of HOP2 in recombination. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Routing protocol for wireless quantum multi-hop mesh backbone network based on partially entangled GHZ state

    Science.gov (United States)

    Xiong, Pei-Ying; Yu, Xu-Tao; Zhang, Zai-Chen; Zhan, Hai-Tao; Hua, Jing-Yu

    2017-08-01

    Quantum multi-hop teleportation is important in the field of quantum communication. In this study, we propose a quantum multi-hop communication model and a quantum routing protocol with multihop teleportation for wireless mesh backbone networks. Based on an analysis of quantum multi-hop protocols, a partially entangled Greenberger-Horne-Zeilinger (GHZ) state is selected as the quantum channel for the proposed protocol. Both quantum and classical wireless channels exist between two neighboring nodes along the route. With the proposed routing protocol, quantum information can be transmitted hop by hop from the source node to the destination node. Based on multi-hop teleportation based on the partially entangled GHZ state, a quantum route established with the minimum number of hops. The difference between our routing protocol and the classical one is that in the former, the processes used to find a quantum route and establish quantum channel entanglement occur simultaneously. The Bell state measurement results of each hop are piggybacked to quantum route finding information. This method reduces the total number of packets and the magnitude of air interface delay. The deduction of the establishment of a quantum channel between source and destination is also presented here. The final success probability of quantum multi-hop teleportation in wireless mesh backbone networks was simulated and analyzed. Our research shows that quantum multi-hop teleportation in wireless mesh backbone networks through a partially entangled GHZ state is feasible.

  11. Condom use and hip hop culture: the case of urban young men in New York City.

    Science.gov (United States)

    Muñoz-Laboy, Miguel A; Castellanos, Daniel H; Haliburton, Chanel S; del Aguila, Ernesto Vasquez; Weinstein, Hannah J; Parker, Richard G

    2008-06-01

    We explored how young men's perceptions of and participation in hip hop culture--urban social and artistic expressions, such as clothing style, breakdancing, graffiti, and rap music--and how contextual factors of the hip hop scene may be associated with their condom use, condom-use self-efficacy, and sense of community. We conducted a cross-sectional survey of 95 African American and Latino men aged 15 to 25 years as part of a 4-year ethnographic study in New York City. Differences in young men's perceptions of and levels of affiliation with hip hop culture were not statistically associated with differences in their sense of community or condom-use self-efficacy. Frequency of participation in the hip hop nightclub scene was the strongest factor negatively associated with condom use. Popular discourses on young men's health risks often blame youths' cultures such as the hip hop culture for increased risk practices but do not critically examine how risk emerges in urban young men's lives and what aspects of youths' culture can be protective. Further research needs to focus on contextual factors of risk such as the role of hip hop nightlife on increased HIV risk.

  12. No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

    Science.gov (United States)

    Gibson, W; Campbell, A; Allison, G

    2013-09-01

    Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Two-Hop Secure Communication Using an Untrusted Relay

    Directory of Open Access Journals (Sweden)

    Xiang He

    2009-01-01

    Full Text Available We consider a source-destination pair that can only communicate through an untrusted intermediate relay node. The intermediate node is willing to employ a designated relaying scheme to facilitate reliable communication between the source and the destination. Yet, the information it relays needs to be kept secret from it. In this two-hop communication scenario, where the use of the untrusted relay node is essential, we find that a positive secrecy rate is achievable. The center piece of the achievability scheme is the help provided by either the destination node with transmission capability, or an external “good samaritan” node. In either case, the helper performs cooperative jamming that confuses the eavesdropping relay and disables it from being able to decipher what it is relaying. We next derive an upper bound on the secrecy rate for this system. We observe that the gap between the upper bound and the achievable rate vanishes as the power of the relay node goes to infinity. Overall, the paper presents a case for intentional interference, that is, cooperative jamming, as an enabler for secure communication.

  14. Two-hop Secure Communication Using an Untrusted Relay

    CERN Document Server

    He, Xiang

    2009-01-01

    We consider a source-destination pair that can only communicate through an untrusted intermediate relay node. The intermediate node is willing to employ a designated relaying scheme to facilitate reliable communication between the source and the destination. Yet, the information it relays needs to be kept secret from it. In this two-hop communication scenario, where the use of the untrusted relay node is essential, we find that a positive secrecy rate is achievable. The center piece of the achievability scheme is the help provided by either the destination node with transmission capability, or an external "good samaritan" node. In either case, the helper performs cooperative jamming that confuses the eavesdropping relay and disables it from being able to decipher what it is relaying. We next derive an upper bound on the secrecy rate for this system. We observe that the gap between the upper bound and the achievable rate vanishes as the power of the relay node goes to infinity. Overall, the paper presents a ca...

  15. Power and delay optimisation in multi-hop wireless networks

    KAUST Repository

    Xia, Li

    2014-02-05

    In this paper, we study the optimisation problem of transmission power and delay in a multi-hop wireless network consisting of multiple nodes. The goal is to determine the optimal policy of transmission rates at various buffer and channel states in order to minimise the power consumption and the queueing delay of the whole network. With the assumptions of interference-free links and independently and identically distributed (i.i.d.) channel states, we formulate this problem using a semi-open Jackson network model for data transmission and a Markov model for channel states transition. We derive a difference equation of the system performance under any two different policies. The necessary and sufficient condition of optimal policy is obtained. We also prove that the system performance is monotonic with respect to (w.r.t.) the transmission rate and the optimal transmission rate can be either maximal or minimal. That is, the ‘bang-bang’ control is an optimal control. This optimality structure greatly reduces the problem complexity. Furthermore, we develop an iterative algorithm to find the optimal solution. Finally, we conduct the simulation experiments to demonstrate the effectiveness of our approach. We hope our work can shed some insights on solving this complicated optimisation problem.

  16. Nonlinear hopping transport in ring systems and open channels.

    Science.gov (United States)

    Einax, Mario; Körner, Martin; Maass, Philipp; Nitzan, Abraham

    2010-01-21

    We study the nonlinear hopping transport in one-dimensional rings and open channels. Analytical results are derived for the stationary current response to a constant bias without assuming any specific coupling of the rates to the external fields. It is shown that anomalous large effective jump lengths, as observed in recent experiments by taking the ratio of the third-order nonlinear and the linear conductivity, can occur already in ordered systems. Rectification effects due to site energy disorder in ring systems are expected to become irrelevant for large system sizes. In open channels, in contrast, rectification effects occur already for disorder in the jump barriers and do not vanish in the thermodynamic limit. Numerical solutions for a sinusoidal bias show that the ring system provides a good description for the transport behavior in the open channel for intermediate and high frequencies. For low frequencies temporal variations in the mean particle number have to be taken into account in the open channel, which cannot be captured in the more simple ring model.

  17. Child-Mediated Stroke Communication: Findings from Hip Hop Stroke

    Science.gov (United States)

    Williams, Olajide; DeSorbo, Alexandra; Noble, James; Gerin, William

    2011-01-01

    Background and Purpose Low thrombolysis rates for acute ischemic stroke is linked to delays in seeking immediate treatment due to low public stroke awareness. We aimed to assess whether “Child-Mediated Stroke Communication” (CMSC) could improve stroke literacy parents of children enrolled in a school-based stroke literacy program called Hip Hop Stroke (HHS). Methods Parents of children aged 9 to 12 years from two public schools in Harlem, NYC, were recruited to participate in stroke literacy questionnaires before and after their child’s participation in HHS, a novel CMSC intervention delivered in school auditoriums. Parental recall of stroke information communicated through their child was assessed 1-week following the intervention. Results Fifth and Sixth grade students (n =182) were enrolled into HHS. 102 parents were approached in person to participate; 75 opted to participate and 71 completed both pretest and post-test (74% response rate and 95% retention rate). Parental stroke literacy improved after the program: before the program, 3 parents of 75 (3.9%) were able to identify the five cardinal stroke symptoms, distracting symptom (chest pains), and had an urgent action plan (calling 911), compared to 21 of 71 parents (29.6%) post-intervention (pstroke signs and symptoms remains low among residents of this high-risk population. The use of Child-Mediated Stroke Communication suggests that schoolchildren aged 9-12 may be effective conduits of critical stroke knowledge to their Parents. PMID:22033995

  18. El griot no ha muerto, viva el hip-hop

    Directory of Open Access Journals (Sweden)

    Fco. Javier González García-Mamely

    2015-11-01

    Full Text Available La oratura en África ha jugado un papel vital a lo largo de los milenios como un (único medio de preservar y transmitir la historia, la cultura y el imaginario de cada comunidad. El griot es un claro modelo de las artes orales, pero ha sufrido cambios drásticos en su modo de vida y en los recursos narrativos de los que dispone. Tras el mecenazgo de los grandes reyes y las sucesivas llegadas del islam, el colonialismo y los procesos de modernización y occidentalización, los griots se han tenido que adaptar a nuevos patrones, audiencias y medios de comunicación, convirtiéndose en políticos o en figuras del espectáculo. La aparición del rap y el hip-hop reclamando ser los “modernos griots” ha ocasionado una respuesta crítica y una atracción viral hacia el nuevo fenómeno, sea éste un nuevo género o una reinvención de la oratura del antiguo griot.

  19. Family-based hip-hop to health: outcome results.

    Science.gov (United States)

    Fitzgibbon, Marian L; Stolley, Melinda R; Schiffer, Linda; Kong, Angela; Braunschweig, Carol L; Gomez-Perez, Sandra L; Odoms-Young, Angela; Van Horn, Linda; Christoffel, Katherine Kaufer; Dyer, Alan R

    2013-02-01

    This pilot study tested the feasibility of Family-Based Hip-Hop to Health, a school-based obesity prevention intervention for 3-5-year-old Latino children and their parents, and estimated its effectiveness in producing smaller average changes in BMI at 1-year follow-up. Four Head Start preschools administered through the Chicago Public Schools were randomly assigned to receive a Family-Based Intervention (FBI) or a General Health Intervention (GHI). Parents signed consent forms for 147 of the 157 children enrolled. Both the school-based and family-based components of the intervention were feasible, but attendance for the parent intervention sessions was low. Contrary to expectations, a downtrend in BMI Z-score was observed in both the intervention and control groups. While the data reflect a downward trend in obesity among these young Hispanic children, obesity rates remained higher at 1-year follow-up (15%) than those reported by the National Health and Nutrition Examination Survey (2009-2010) for 2-5-year-old children (12.1%). Developing evidence-based strategies for obesity prevention among Hispanic families remains a challenge. Copyright © 2012 The Obesity Society.

  20. Power and delay optimisation in multi-hop wireless networks

    Science.gov (United States)

    Xia, Li; Shihada, Basem

    2014-06-01

    In this paper, we study the optimisation problem of transmission power and delay in a multi-hop wireless network consisting of multiple nodes. The goal is to determine the optimal policy of transmission rates at various buffer and channel states in order to minimise the power consumption and the queueing delay of the whole network. With the assumptions of interference-free links and independently and identically distributed (i.i.d.) channel states, we formulate this problem using a semi-open Jackson network model for data transmission and a Markov model for channel states transition. We derive a difference equation of the system performance under any two different policies. The necessary and sufficient condition of optimal policy is obtained. We also prove that the system performance is monotonic with respect to (w.r.t.) the transmission rate and the optimal transmission rate can be either maximal or minimal. That is, the 'bang-bang' control is an optimal control. This optimality structure greatly reduces the problem complexity. Furthermore, we develop an iterative algorithm to find the optimal solution. Finally, we conduct the simulation experiments to demonstrate the effectiveness of our approach. We hope our work can shed some insights on solving this complicated optimisation problem.

  1. Self-dual quasiperiodic systems with power-law hopping

    Science.gov (United States)

    Gopalakrishnan, Sarang

    2017-08-01

    We introduce and explore a family of self-dual models of single-particle motion in quasiperiodic potentials, with hopping amplitudes that fall off as a power law with exponent p . These models are generalizations of the familiar Aubry-André model. For large enough p , their static properties are similar to those of the Aubry-André model, although the low-frequency conductivity in the localized phase is sensitive to p . For p ≲2.1 the Aubry-André localization transition splits into three transitions; two distinct intermediate regimes with both localized and delocalized states appear near the self-dual point of the Aubry-André model. In the intermediate regimes, the density of states is singular continuous in much of the spectrum, and is approximately self-similar: states form narrow energy bands, which are divided into yet narrower subbands; we find no clear sign of a mobility edge. When p law is recovered when the power law is slowly decaying. We present evidence that many of these features persist in models that are away from self-duality.

  2. Evidence for multiple mechanisms of crustal contamination of magma from compositionally zoned plutons and associated ultramafic intrusions of the Alaska Range

    Science.gov (United States)

    Reiners, P.W.; Nelson, B.K.; Nelson, S.W.

    1996-01-01

    Models of continental crustal magmagenesis commonly invoke the interaction of mafic mantle-derived magma and continental crust to explain geochemical and petrologic characteristics of crustal volcanic and plutonic rocks. This interaction and the specific mechanisms of crustal contamination associated with it are poorly understood. An excellent opportunity to study the progressive effects of crustal contamination is offered by the composite plutons of the Alaska Range, a series of nine early Tertiary, multiply intruded, compositionally zoned (peridotite to granite) plutons. Large initial Sr and Nd isotopic contrasts between the crustal country rock and likely parental magmas allow evaluation of the mechanisms and extents of crustal contamination that accompanied the crystallization of these ultramafic through granitic rocks. Three contamination processes are distinguished in these plutons. The most obvious of these is assimilation of crustal country rock concurrent with magmatic fractional crystallization (AFC), as indicated by a general trend toward crustal-like isotopic signatures with increasing differentiation. Second, many ultramafic and mafic rocks have late-stage phenocryst reaction and orthocumulate textures that suggest interaction with felsic melt. These rocks also have variable and enriched isotopic compositions that suggest that this felsic melt was isotopically enriched and probably derived from crustal country rock. Partial melt from the flysch country rock may have reacted with and contaminated these partly crystalline magmas following the precipitation and accumulation of the cumulus phenocrysts but before complete solidification of the magma. This suggests that in magmatic mush (especially of ultramafic composition) crystallizing in continental crust, a second distinct process of crustal contamination may be super-imposed on AFC or magma mixing involving the main magma body. Finally, nearly all rocks, including mafic and ultramafic rocks, have (87Sr

  3. Xanthohumol, a Prenylated Flavonoid from Hops (Humulus lupulus, Prevents Platelet Activation in Human Platelets

    Directory of Open Access Journals (Sweden)

    Ye-Ming Lee

    2012-01-01

    Full Text Available Xanthohumol is the principal prenylated flavonoid in the hop plant (Humulus lupulus L.. Xanthohumol was found to be a very potent cancer chemopreventive agent through regulation of diverse mechanisms. However, no data are available concerning the effects of xanthohumol on platelet activation. The aim of this paper was to examine the antiplatelet effect of xanthohumol in washed human platelets. In the present paper, xanthohumol exhibited more-potent activity in inhibiting platelet aggregation stimulated by collagen. Xanthohumol inhibited platelet activation accompanied by relative [Ca2+]i mobilization, thromboxane A2 formation, hydroxyl radical (OH● formation, and phospholipase C (PLCγ2, protein kinase C (PKC, mitogen-activated protein kinase (MAPK, and Akt phosphorylation. Neither SQ22536, an inhibitor of adenylate cyclase, nor ODQ, an inhibitor of guanylate cyclase, reversed the xanthohumol-mediated inhibitory effect on platelet aggregation. Furthermore, xanthohumol did not significantly increase nitrate formation in platelets. This study demonstrates for the first time that xanthohumol possesses potent antiplatelet activity which may initially inhibit the PI3-kinase/Akt, p38 MAPK, and PLCγ2-PKC cascades, followed by inhibition of the thromboxane A2 formation, thereby leading to inhibition of [Ca2+]i and finally inhibition of platelet aggregation. Therefore, this novel role of xanthohumol may represent a high therapeutic potential for treatment or prevention of cardiovascular diseases.

  4. Wide-range screening of anti-inflammatory compounds in tomato using LC-MS and elucidating the mechanism of their functions.

    Directory of Open Access Journals (Sweden)

    Shinsuke Mohri

    Full Text Available Obesity-induced chronic inflammation is a key factor in type 2 diabetes. A vicious cycle involving pro-inflammatory mediators between adipocytes and macrophages is a common cause of chronic inflammation in the adipose tissue. Tomato is one of the most popular vegetables and is associated with a reduced risk of diabetes. However, the molecular mechanism underlying the effect of tomato on diabetes is unclear. In this study, we focused on anti-inflammatory compounds in tomato. We found that the extract of tomato reduced plasma glucose and inflammatory markers in mice. We screened anti-inflammatory fractions in tomato using lipopolysaccharide-stimulated RAW264.7 macrophages, and active compounds were estimated by liquid chromatography-mass spectrometry over a wide range. Surprisingly, a large number of compounds including oxylipin and coumarin derivatives were estimated as anti-inflammatory compounds. Especially, 9-oxo-octadecadienoic acid and daphnetin suppressed pro-inflammatory cytokines in RAW264.7 macrophages inhibiting mitogen-activated protein kinase phosphorylation and inhibitor of kappa B α protein degradation. These findings suggest that tomato containing diverse anti-inflammatory compounds ameliorates chronic inflammation in obese adipose tissue.

  5. Wide-range screening of anti-inflammatory compounds in tomato using LC-MS and elucidating the mechanism of their functions.

    Science.gov (United States)

    Mohri, Shinsuke; Takahashi, Haruya; Sakai, Maiko; Takahashi, Shingo; Waki, Naoko; Aizawa, Koichi; Suganuma, Hiroyuki; Ara, Takeshi; Matsumura, Yasuki; Shibata, Daisuke; Goto, Tsuyoshi; Kawada, Teruo

    2018-01-01

    Obesity-induced chronic inflammation is a key factor in type 2 diabetes. A vicious cycle involving pro-inflammatory mediators between adipocytes and macrophages is a common cause of chronic inflammation in the adipose tissue. Tomato is one of the most popular vegetables and is associated with a reduced risk of diabetes. However, the molecular mechanism underlying the effect of tomato on diabetes is unclear. In this study, we focused on anti-inflammatory compounds in tomato. We found that the extract of tomato reduced plasma glucose and inflammatory markers in mice. We screened anti-inflammatory fractions in tomato using lipopolysaccharide-stimulated RAW264.7 macrophages, and active compounds were estimated by liquid chromatography-mass spectrometry over a wide range. Surprisingly, a large number of compounds including oxylipin and coumarin derivatives were estimated as anti-inflammatory compounds. Especially, 9-oxo-octadecadienoic acid and daphnetin suppressed pro-inflammatory cytokines in RAW264.7 macrophages inhibiting mitogen-activated protein kinase phosphorylation and inhibitor of kappa B α protein degradation. These findings suggest that tomato containing diverse anti-inflammatory compounds ameliorates chronic inflammation in obese adipose tissue.

  6. FRET-Mediated Long-Range Wavelength Transformation by Photoconvertible Fluorescent Proteins as an Efficient Mechanism to Generate Orange-Red Light in Symbiotic Deep Water Corals

    Science.gov (United States)

    Bollati, Elena; Plimmer, Daniel; D’Angelo, Cecilia; Wiedenmann, Jörg

    2017-01-01

    Photoconvertible fluorescent proteins (pcRFPs) are a group of fluorophores that undergo an irreversible green-to-red shift in emission colour upon irradiation with near-ultraviolet (near-UV) light. Despite their wide application in biotechnology, the high-level expression of pcRFPs in mesophotic and depth-generalist coral species currently lacks a biological explanation. Additionally, reduced penetration of near-UV wavelengths in water poses the question whether light-driven photoconversion is relevant in the mesophotic zone, or whether a different mechanism is involved in the post-translational pigment modification in vivo. Here, we show in a long-term mesocosm experiment that photoconversion in vivo is entirely dependent on near-UV wavelengths. However, a near-UV intensity equivalent to the mesophotic underwater light field at 80 m depth is sufficient to drive the process in vitro, suggesting that photoconversion can occur near the lower distribution limits of these corals. Furthermore, live coral colonies showed evidence of efficient Förster Resonance Energy Transfer (FRET). Our simulated mesophotic light field maintained the pcRFP pool in a partially photoconverted state in vivo, maximising intra-tetrameric FRET and creating a long-range wavelength conversion system with higher quantum yield than other native RFPs. We hypothesise that efficient conversion of blue wavelengths, abundant at depth, into orange-red light could constitute an adaptation of corals to life in light-limited environments. PMID:28677653

  7. FRET-Mediated Long-Range Wavelength Transformation by Photoconvertible Fluorescent Proteins as an Efficient Mechanism to Generate Orange-Red Light in Symbiotic Deep Water Corals.

    Science.gov (United States)

    Bollati, Elena; Plimmer, Daniel; D'Angelo, Cecilia; Wiedenmann, Jörg

    2017-07-04

    Photoconvertible fluorescent proteins (pcRFPs) are a group of fluorophores that undergo an irreversible green-to-red shift in emission colour upon irradiation with near-ultraviolet (near-UV) light. Despite their wide application in biotechnology, the high-level expression of pcRFPs in mesophotic and depth-generalist coral species currently lacks a biological explanation. Additionally, reduced penetration of near-UV wavelengths in water poses the question whether light-driven photoconversion is relevant in the mesophotic zone, or whether a different mechanism is involved in the post-translational pigment modification in vivo. Here, we show in a long-term mesocosm experiment that photoconversion in vivo is entirely dependent on near-UV wavelengths. However, a near-UV intensity equivalent to the mesophotic underwater light field at 80 m depth is sufficient to drive the process in vitro, suggesting that photoconversion can occur near the lower distribution limits of these corals. Furthermore, live coral colonies showed evidence of efficient Förster Resonance Energy Transfer (FRET). Our simulated mesophotic light field maintained the pcRFP pool in a partially photoconverted state in vivo, maximising intra-tetrameric FRET and creating a long-range wavelength conversion system with higher quantum yield than other native RFPs. We hypothesise that efficient conversion of blue wavelengths, abundant at depth, into orange-red light could constitute an adaptation of corals to life in light-limited environments.

  8. Power distribution of a co-axial dual-mechanical-port flux-switching permanent magnet machine for fuel-based extended range electric vehicles

    Directory of Open Access Journals (Sweden)

    Lingkang Zhou

    2017-05-01

    Full Text Available In this paper, power distribution between the inner and outer machines of a co-axial dual-mechanical-port flux-switching permanent magnet (CADMP-FSPM machine is investigated for fuel-based extended range electric vehicle (ER-EV. Firstly, the topology and operation principle of the CADMP-FSPM machine are introduced, which consist of an inner FSPM machine used for high-speed, an outer FSPM machine for low-speed, and a magnetic isolation ring between them. Then, the magnetic field coupling of the inner and outer FSPM machines is analyzed with more attention paid to the optimization of the isolation ring thickness. Thirdly, the power-dimension (PD equations of the inner and outer FSPM machines are derived, respectively, and thereafter, the PD equation of the whole CADMP-FSPM machine can be given. Finally, the PD equations are validated by finite element analysis, which supplies the guidance on the design of this type of machines.

  9. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  10. Antimicrobial activity of hop extracts against foodborne pathogens for meat applications.

    Science.gov (United States)

    Kramer, B; Thielmann, J; Hickisch, A; Muranyi, P; Wunderlich, J; Hauser, C

    2015-03-01

    The objective of this study was the fundamental investigation of the antimicrobial efficiency of various hop extracts against selected foodborne pathogens in vitro, as well as their activity against Listeria monocytogenes in a model meat marinade and on marinated pork tenderloins. In a first step, the minimum inhibitory concentrations (MIC) of three hop extracts containing either α- or β-acids or xanthohumol were determined against test bacteria including L. monocytogenes, Staphylococcus aureus, Salmonella enterica and Escherichia coli by a colorimetric method based on the measurement of bacterial metabolic activity. Moreover, the influence of either lactic or citric acid on the antimicrobial activity of the hop extracts was evaluated. The efficiency of hop extracts as a natural food preservative was then tested in a model meat marinade at 2 and 8°C, respectively, and finally on marinated pork. The experiments showed that Gram-positive bacteria were strongly inhibited by hop extracts containing β-acids and xanthohumol (MIC values of 6.3 and 12.5 ppm, respectively), whereas the antimicrobial activity of the investigated α-acid extract was significantly lower (MIC values of 200 ppm). Gram-negative bacteria were highly resistant against all tested hop extracts. Acidification of the test media led to a decrease of the MIC values. The inhibitory activity of the hop extracts against L. monocytogenes was strongly reduced in a fat-containing model meat marinade, but the efficiency of β-acids in this matrix could be increased by lowering pH and storage temperatures. By applying 0.5 % β-acids at pH = 5 in a model marinade, the total aerobic count of pork tenderloins was reduced up to 0.9 log10 compared with marinated pork without hop extract after 2 weeks of storage at 5°C. β-acid containing hop extracts have proven to possess a high antimicrobial activity against Gram-positive bacteria in vitro and in a practice-related application for food preservation

  11. Characterization of Volatile Components from Hüller Bitterer Hop Variety Using In-Tube Extraction GC-MS Analysis

    Directory of Open Access Journals (Sweden)

    Liana Claudia Salanță

    2015-05-01

    Full Text Available The composition of hop oil contributes to the aroma of beer and the essential oil profile of hop samples contains valuable information for brewers. The aim of this study was to characterize the Hüller Bitterer hop variety, during the development of hop cones, by analysis the composition of volatile oil using in-tube extraction gas chromatography–mass spectrometry (ITEX-GC–MS. The obtained results show that the ITEX-GC/MS method is suitable for the determination of volatile compounds from hop samples. A number of 60 compounds were separated and 50 of them were identified. The most important volatile compounds found in Hüller Bitterer hop variety belonging to the monoterpenes and sesquiterpenes classes are represented by: β-myrcene, β-caryophyllene and α-humulene. 

  12. Characterization of novel varietal floral hop aromas by headspace solid phase microextraction and gas chromatography-mass spectrometry/olfactometry.

    Science.gov (United States)

    Van Opstaele, Filip; De Causmaecker, Brecht; Aerts, Guido; De Cooman, Luc

    2012-12-19

    In this study, headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were optimized and implemented to investigate the volatile composition of novel floral hop essences prepared from four German aroma hop varieties. In total, 91 different constituents were assigned, which were further grouped into monoterpene hydrocarbons, esters, ketones, aldehydes, furans, and oxygenated and nonoxygenated sesquiterpenes. Most volatiles belong to the ester group, whereas the monoterpene hydrocarbon β-myrcene appears to be the predominant compound in all hop oil preparations investigated. Furthermore, as demonstrated by principal component analysis, varietal floral hop essences are clearly discriminated on the basis of their characteristic volatile composition. Via GC-olfactometry on the floral essence variety Spalter Select, β-myrcene and 2-undecanone were identified as the most potent odorants. Several hop oil constituents were reported for the first time as impact odorants of hop aroma.

  13. Dynamics and Diffusion Mechanism of Low-Density Liquid Silicon.

    Science.gov (United States)

    Shen, B; Wang, Z Y; Dong, F; Guo, Y R; Zhang, R J; Zheng, Y X; Wang, S Y; Wang, C Z; Ho, K M; Chen, L Y

    2015-11-25

    A first-order phase transition from a high-density liquid to a low-density liquid has been proposed to explain the various thermodynamic anomies of water. It also has been proposed that such liquid-liquid phase transition would exist in supercooled silicon. Computer simulation studies show that, across the transition, the diffusivity drops roughly 2 orders of magnitude, and the structures exhibit considerable tetrahedral ordering. The resulting phase is a highly viscous, low-density liquid silicon. Investigations on the atomic diffusion of such a novel form of liquid silicon are of high interest. Here we report such diffusion results from molecular dynamics simulations using the classical Stillinger-Weber (SW) potential of silicon. We show that the atomic diffusion of the low-density liquid is highly correlated with local tetrahedral geometries. We also show that atoms diffuse through hopping processes within short ranges, which gradually accumulate to an overall random motion for long ranges as in normal liquids. There is a close relationship between dynamical heterogeneity and hopping process. We point out that the above diffusion mechanism is closely related to the strong directional bonding nature of the distorted tetrahedral network. Our work offers new insights into the complex behavior of the highly viscous low density liquid silicon, suggesting similar diffusion behaviors in other tetrahedral coordinated liquids that exhibit liquid-liquid phase transition such as carbon and germanium.

  14. Within-field distribution of the damson-hop aphid Phorodon humuli (Schrank (Hemiptera: Aphididae and natural enemies on hops in Spain

    Directory of Open Access Journals (Sweden)

    Alicia Lorenzana

    2017-07-01

    Full Text Available A field trial was performed in a hop yard throughout 2002, 2003 and 2004 in order to determine the within-field distribution of Phorodon humuli (Schrank (Hemiptera: Aphididae and its natural enemies. The distribution of P. humuli was directly affected by the position of the hop plants in the garden, with significantly higher concentrations of aphids (p=0.0122 in 2002 and p=0.0006 in 2003 observed along the edge. However, in 2004 the plants located on the marginal plots had similar populations to those on the more inner plots. This can be explained by a higher wind speed which made it more difficult to land on edge plants first. The hop aphid’s main natural enemy was Coccinella septempunctata (Coleoptera: Coccinellidae, whose population was greatest where the aphids were most abundant with a significantly greater number of eggs (p=0.0230 and adults (p=0.0245 in 2003. Lacewing eggs were also frequently observed, with a significantly higher population (p=0.0221 in 2003 and p=0.0046 in 2004 where the aphid numbers were high. The number of winged aphids was greatest towards the margins of the garden in 2003. It is argued that the spatial distribution of the hop aphid and its natural enemies could be used to plan a sampling program and to estimate the population densities of these insects for use in integrated pest management programs.

  15. Hip-Hop High School: A Study of the Attitudes, Beliefs and Perceptions of Suburban High School Faculty towards Representation of the Hip-Hop Culture

    Science.gov (United States)

    Rowland, Ronald K.

    2011-01-01

    Research historically has demonstrated that a generational disconnect between the popular cultures from which students and teachers define normative behavior can impact classroom management and student learning. The purpose of this study was to examine attitudes, beliefs and perceptions of high school faculty toward the hip-hop culture and its…

  16. Efficient DV-HOP Localization for Wireless Cyber-Physical Social Sensing System: A Correntropy-Based Neural Network Learning Scheme

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2017-01-01

    Full Text Available Integrating wireless sensor network (WSN into the emerging computing paradigm, e.g., cyber-physical social sensing (CPSS, has witnessed a growing interest, and WSN can serve as a social network while receiving more attention from the social computing research field. Then, the localization of sensor nodes has become an essential requirement for many applications over WSN. Meanwhile, the localization information of unknown nodes has strongly affected the performance of WSN. The received signal strength indication (RSSI as a typical range-based algorithm for positioning sensor nodes in WSN could achieve accurate location with hardware saving, but is sensitive to environmental noises. Moreover, the original distance vector hop (DV-HOP as an important range-free localization algorithm is simple, inexpensive and not related to the environment factors, but performs poorly when lacking anchor nodes. Motivated by these, various improved DV-HOP schemes with RSSI have been introduced, and we present a new neural network (NN-based node localization scheme, named RHOP-ELM-RCC, through the use of DV-HOP, RSSI and a regularized correntropy criterion (RCC-based extreme learning machine (ELM algorithm (ELM-RCC. Firstly, the proposed scheme employs both RSSI and DV-HOP to evaluate the distances between nodes to enhance the accuracy of distance estimation at a reasonable cost. Then, with the help of ELM featured with a fast learning speed with a good generalization performance and minimal human intervention, a single hidden layer feedforward network (SLFN on the basis of ELM-RCC is used to implement the optimization task for obtaining the location of unknown nodes. Since the RSSI may be influenced by the environmental noises and may bring estimation error, the RCC instead of the mean square error (MSE estimation, which is sensitive to noises, is exploited in ELM. Hence, it may make the estimation more robust against outliers. Additionally, the least square

  17. Efficient DV-HOP Localization for Wireless Cyber-Physical Social Sensing System: A Correntropy-Based Neural Network Learning Scheme.

    Science.gov (United States)

    Xu, Yang; Luo, Xiong; Wang, Weiping; Zhao, Wenbing

    2017-01-12

    Integrating wireless sensor network (WSN) into the emerging computing paradigm, e.g., cyber-physical social sensing (CPSS), has witnessed a growing interest, and WSN can serve as a social network while receiving more attention from the social computing research field. Then, the localization of sensor nodes has become an essential requirement for many applications over WSN. Meanwhile, the localization information of unknown nodes has strongly affected the performance of WSN. The received signal strength indication (RSSI) as a typical range-based algorithm for positioning sensor nodes in WSN could achieve accurate location with hardware saving, but is sensitive to environmental noises. Moreover, the original distance vector hop (DV-HOP) as an important range-free localization algorithm is simple, inexpensive and not related to the environment factors, but performs poorly when lacking anchor nodes. Motivated by these, various improved DV-HOP schemes with RSSI have been introduced, and we present a new neural network (NN)-based node localization scheme, named RHOP-ELM-RCC, through the use of DV-HOP, RSSI and a regularized correntropy criterion (RCC)-based extreme learning machine (ELM) algorithm (ELM-RCC). Firstly, the proposed scheme employs both RSSI and DV-HOP to evaluate the distances between nodes to enhance the accuracy of distance estimation at a reasonable cost. Then, with the help of ELM featured with a fast learning speed with a good generalization performance and minimal human intervention, a single hidden layer feedforward network (SLFN) on the basis of ELM-RCC is used to implement the optimization task for obtaining the location of unknown nodes. Since the RSSI may be influenced by the environmental noises and may bring estimation error, the RCC instead of the mean square error (MSE) estimation, which is sensitive to noises, is exploited in ELM. Hence, it may make the estimation more robust against outliers. Additionally, the least square estimation (LSE

  18. Long range epigenetic silencing is a trans-species mechanism that results in cancer specific deregulation by overriding the chromatin domains of normal cells.

    Science.gov (United States)

    Forn, Marta; Muñoz, Mar; Tauriello, Daniele V F; Merlos-Suárez, Anna; Rodilla, Verónica; Bigas, Anna; Batlle, Eduard; Jordà, Mireia; Peinado, Miguel A

    2013-12-01

    DNA methylation and chromatin remodeling are frequently implicated in the silencing of genes involved in carcinogenesis. Long Range Epigenetic Silencing (LRES) is a mechanism of gene inactivation that affects multiple contiguous CpG islands and has been described in different human cancer types. However, it is unknown whether there is a coordinated regulation of the genes embedded in these regions in normal cells and in early stages of tumor progression. To better characterize the molecular events associated with the regulation and remodeling of these regions we analyzed two regions undergoing LRES in human colon cancer in the mouse model. We demonstrate that LRES also occurs in murine cancer in vivo and mimics the molecular features of the human phenomenon, namely, downregulation of gene expression, acquisition of inactive histone marks, and DNA hypermethylation of specific CpG islands. The genes embedded in these regions showed a dynamic and autonomous regulation during mouse intestinal cell differentiation, indicating that, in the framework considered here, the coordinated regulation in LRES is restricted to cancer. Unexpectedly, benign adenomas in Apc(Min/+) mice showed overexpression of most of the genes affected by LRES in cancer, which suggests that the repressive remodeling of the region is a late event. Chromatin immunoprecipitation analysis of the transcriptional insulator CTCF in mouse colon cancer cells revealed disrupted chromatin domain boundaries as compared with normal cells. Malignant regression of cancer cells by in vitro differentiation resulted in partial reversion of LRES and gain of CTCF binding. We conclude that genes in LRES regions are plastically regulated in cell differentiation and hyperproliferation, but are constrained to a coordinated repression by abolishing boundaries and the autonomous regulation of chromatin domains in cancer cells. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All

  19. Investigation of conduction mechanism in Pr{sub 0.67}Sr{sub 0.13}Ag{sub 0.20}MnO{sub 3} manganites

    Energy Technology Data Exchange (ETDEWEB)

    Modi, Anchit, E-mail: sehr.masroor1952@gmail.com; Bhat, Masroor Ahamad; Gaur, N. K. [Department of Physics, Barkatullah University, Bhopal-462026 (India)

    2016-05-23

    We report the electronic conduction mechanism in Pr{sub 0.67}Sr{sub 0.13}Ag{sub 0.20}MnO{sub 3} synthesized successfully by conventional solid state reaction method. The compound under investigation was subjected by X – Ray diffraction using Rietveld refinement which confirms the single phase nature of the sample. The resistivity behavior indicates the semiconducting behavior and reduction in resistivity on the application of magnetic fields. The electronic nature can further been evaluated by using variable range hopping (VRH) model and small polaron hopping model (SPH) showing that the double exchange interaction increases suppress the band gap and enhances carrier delocalization on the application of magnetic fields.

  20. Identification of critical chemical features for Aurora kinase-B inhibitors using Hip-Hop, virtual screening and molecular docking

    Science.gov (United States)

    Sakkiah, Sugunadevi; Thangapandian, Sundarapandian; John, Shalini; Lee, Keun Woo

    2011-01-01

    This study was performed to find the selective chemical features for Aurora kinase-B inhibitors using the potent methods like Hip-Hop, virtual screening, homology modeling, molecular dynamics and docking. The best hypothesis, Hypo1 was validated toward a wide range of test set containing the selective inhibitors of Aurora kinase-B. Homology modeling and molecular dynamics studies were carried out to perform the molecular docking studies. The best hypothesis Hypo1 was used as a 3D query to screen the chemical databases. The screened molecules from the databases were sorted based on ADME and drug like properties. The selective hit compounds were docked and the hydrogen bond interactions with the critical amino acids present in Aurora kinase-B were compared with the chemical features present in the Hypo1. Finally, we suggest that the chemical features present in the Hypo1 are vital for a molecule to inhibit the Aurora kinase-B activity.

  1. Salmonella exploits the host endolysosomal tethering factor HOPS complex to promote its intravacuolar replication

    Science.gov (United States)

    Sindhwani, Aastha; Kaur, Harmeet; Tuli, Amit

    2017-01-01

    Salmonella enterica serovar typhimurium extensively remodels the host late endocytic compartments to establish its vacuolar niche within the host cells conducive for its replication, also known as the Salmonella-containing vacuole (SCV). By maintaining a prolonged interaction with late endosomes and lysosomes of the host cells in the form of interconnected network of tubules (Salmonella-induced filaments or SIFs), Salmonella gains access to both membrane and fluid-phase cargo from these compartments. This is essential for maintaining SCV membrane integrity and for bacterial intravacuolar nutrition. Here, we have identified the multisubunit lysosomal tethering factor—HOPS (HOmotypic fusion and Protein Sorting) complex as a crucial host factor facilitating delivery of late endosomal and lysosomal content to SCVs, providing membrane for SIF formation, and nutrients for intravacuolar bacterial replication. Accordingly, depletion of HOPS subunits significantly reduced the bacterial load in non-phagocytic and phagocytic cells as well as in a mouse model of Salmonella infection. We found that Salmonella effector SifA in complex with its binding partner; SKIP, interacts with HOPS subunit Vps39 and mediates recruitment of this tethering factor to SCV compartments. The lysosomal small GTPase Arl8b that binds to, and promotes membrane localization of Vps41 (and other HOPS subunits) was also required for HOPS recruitment to SCVs and SIFs. Our findings suggest that Salmonella recruits the host late endosomal and lysosomal membrane fusion machinery to its vacuolar niche for access to host membrane and nutrients, ensuring its intracellular survival and replication. PMID:29084291

  2. Cascading Multi-Hop Reservation and Transmission in Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jae-Won Lee

    2014-10-01

    Full Text Available The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT. In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U and MACA-U with packet trains (MACA-UPT. The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay.

  3. Integration of intrinsic muscle properties, feed-forward and feedback signals for generating and stabilizing hopping.

    Science.gov (United States)

    Haeufle, D F B; Grimmer, S; Kalveram, K-T; Seyfarth, A

    2012-07-07

    It was hypothesized that a tight integration of feed-forward and feedback-driven muscle activation with the characteristic intrinsic muscle properties is a key feature of locomotion in challenging environments. In this simulation study it was investigated whether a combination of feed-forward and feedback signals improves hopping stability compared with those simulations with one individual type of activation. In a reduced one-dimensional hopping model with a Hill-type muscle (one contractile element, neither serial nor parallel elastic elements), the level of detail of the muscle's force-length-velocity relation and the type of activation generation (feed-forward, feedback and combination of both) were varied to test their influence on periodic hopping. The stability of the hopping patterns was evaluated by return map analysis. It was found that the combination of feed-forward and proprioceptive feedback improved hopping stability. Furthermore, the nonlinear Hill-type representation of intrinsic muscle properties led to a faster reduction of perturbations than a linear approximation, independent of the type of activation. The results emphasize the ability of organisms to exploit the stabilizing properties of intrinsic muscle characteristics.

  4. Multi-hop localization algorithm based on grid-scanning for wireless sensor networks.

    Science.gov (United States)

    Wan, Jiangwen; Guo, Xiaolei; Yu, Ning; Wu, Yinfeng; Feng, Renjian

    2011-01-01

    For large-scale wireless sensor networks (WSNs) with a minority of anchor nodes, multi-hop localization is a popular scheme for determining the geographical positions of the normal nodes. However, in practice existing multi-hop localization methods suffer from various kinds of problems, such as poor adaptability to irregular topology, high computational complexity, low positioning accuracy, etc. To address these issues in this paper, we propose a novel Multi-hop Localization algorithm based on Grid-Scanning (MLGS). First, the factors that influence the multi-hop distance estimation are studied and a more realistic multi-hop localization model is constructed. Then, the feasible regions of the normal nodes are determined according to the intersection of bounding square rings. Finally, a verifiably good approximation scheme based on grid-scanning is developed to estimate the coordinates of the normal nodes. Additionally, the positioning accuracy of the normal nodes can be improved through neighbors' collaboration. Extensive simulations are performed in isotropic and anisotropic networks. The comparisons with some typical algorithms of node localization confirm the effectiveness and efficiency of our algorithm.

  5. Optimal hop position-based minimum energy routing protocol for underwater acoustic sensor networks

    Directory of Open Access Journals (Sweden)

    K.S. Geethu

    2015-05-01

    Full Text Available Development of energy-efficient routing protocols is a major concern in the design of underwater acoustic sensor networks (UASNs since UASN nodes are typically powered by batteries, which are difficult to replace or recharge in aquatic environments. This study proposes an optimal hop position-based energy-efficient routing protocol for UASNs. Initially, the authors present an analytical model to compute the total energy consumption in a multi-hop UASN for deep water scenario, taking into account dependence of usable bandwidth on transmission distance and propagation characteristics of underwater acoustic channel. They derive analytical solution for the optimal hop distance that minimises total energy consumption in the network. They then propose an energy-efficient routing protocol that relies on the computation of optimal hop distance. In their routing scheme, selection of forwarding nodes are based on their depth, residual energy and closeness to the computed optimal hop position corresponding to source node. Simulation results show that total energy consumption of the network gets reduced drastically, leading to improvement in network lifetime. Moreover, the proposed routing scheme makes use of courier nodes to handle coverage-hole problem. The efficient movement of courier nodes improves packet delivery ratio and network throughput.

  6. Culturas juveniles en tono de mujer. Hip hop en Medellín (Colombia.

    Directory of Open Access Journals (Sweden)

    Ángela Garcés Montoya.

    2011-04-01

    Full Text Available This article is part of the research project, “Youth musical mediations,” that explores the appropriation of alternative means of communication which allow the young to develop identities sharply differentiated from those the adult world. In particular, the article examines the world of hip hop in Medellín and the ways that youth participate in it. To follow key trajectories of women in hip hop, their voices, feelings, and memories must be uncovered. This will allow us to see how the few women who are currently part of hip hop scene in Medellín and Colombia enter, move through, and persevere in it. Since women constitute only a small percentage of the youth who live and remake hip hop in Medellín, it is important to understand how they manage to live in a male-colored world. If hip hop is about strength, denunciation, confrontation, and resistance, it seems that these qualities are more appropriate for men than for women

  7. Defined subunit arrangement and rab interactions are required for functionality of the HOPS tethering complex.

    Science.gov (United States)

    Ostrowicz, Clemens W; Bröcker, Cornelia; Ahnert, Franziska; Nordmann, Mirjana; Lachmann, Jens; Peplowska, Karolina; Perz, Angela; Auffarth, Kathrin; Engelbrecht-Vandré, Siegfried; Ungermann, Christian

    2010-10-01

    Within the endomembrane system of eukaryotic cells, multisubunit tethering complexes together with their corresponding Rab-GTPases coordinate vesicle tethering and fusion. Here, we present evidence that two homologous hexameric tethering complexes, the endosomal CORVET (Class C core vacuole/endosome transport) and the vacuolar HOPS (homotypic vacuole fusion and protein sorting) complex, have similar subunit topologies. Both complexes contain two Rab-binding proteins at one end, and the Sec1/Munc18-like Vps33 at the opposite side, suggesting a model on membrane bridging via Rab-GTP and SNARE binding. In agreement, HOPS activity can be reconstituted using purified subcomplexes containing the Rab and Vps33 module, but requires all six subunits for activity. At the center of HOPS and CORVET, the class C proteins Vps11 and Vps18 connect the two parts, and Vps11 binds both HOPS Vps39 and CORVET Vps3 via the same binding site. As HOPS Vps39 is also found at endosomes, our data thus suggest that these tethering complexes follow defined but distinct assembly pathways, and may undergo transition by simple subunit interchange. © 2010 John Wiley & Sons A/S.

  8. Joint Scheduling for Dual-Hop Block-Fading Broadcast Channels

    KAUST Repository

    Zafar, Ammar

    2012-09-16

    In this paper, we propose joint user-and-hop scheduling over dual-hop block-fading broadcast channels in order to exploit multi-user diversity gains and multi-hop diversity gains all together. To achieve this objective, the first and second hops are scheduled opportunistically based on the channel state information and as a prerequisite we assume that the relay, which is half-duplex and operates using decode-and-forward, is capable of storing the received packets from the source until the channel condition of the destined user becomes good to be scheduled. We formulate the joint scheduling problem as maximizing the weighted sum of the long term achievable rates by the users under a stability constraint, which means that on the long term the rate received by the relay should equal the rate transmitted by it, in addition to constant or variable power constraints. We show that this problem is equivalent to a single-hop broadcast channel by treating the source as a virtual user with an optimal priority weight that maintains the stability constraint. We show how to obtain the source weight either off-line based on channel statistics or on real-time based on channel measurements. Furthermore, we consider special cases including the maximum sum rate scheduler and the proportional fair scheduler. We demonstrate via numerical results that our proposed joint scheduling scheme enlarges the rate region as compared with a scheme that employs multi-user scheduling alone.

  9. Hip-Hop to Health Jr. Randomized Effectiveness Trial

    Science.gov (United States)

    Kong, Angela; Buscemi, Joanna; Stolley, Melinda R.; Schiffer, Linda A.; Kim, Yoonsang; Braunschweig, Carol L.; Gomez-Perez, Sandra L.; Blumstein, Lara B.; Van Horn, Linda; Dyer, Alan R.; Fitzgibbon, Marian L.

    2015-01-01

    Introduction The preschool years provide a unique window of opportunity to intervene on obesity-related lifestyle risk factors during the formative years of a child’s life. The purpose of this study was to assess the impact of a preschool-based obesity prevention effectiveness trial at 1-year follow-up. Design RCT. Settings/participants Primarily African American children (aged 3–5 years, N=618) attending Head Start preschool programs administered by Chicago Public Schools. Methods Eighteen preschools were randomly assigned in 2007–2008 to receive either: (1) a 14-week teacher-delivered intervention focused on healthy lifestyle behaviors; or (2) a 14-week teacher-delivered general health curriculum (control group). Main outcome measures The primary outcome, BMI, was measured at baseline, post-intervention, and 1-year follow-up. Diet and screen time behaviors were also assessed at these time points. Multilevel mixed effects models were used to test for between-group differences. Data were analyzed in 2014. Results Significant between-group differences were observed in diet, but not in BMI z-score or screen time at 1-year follow-up. Diet differences favored the intervention arm over controls in overall diet quality (p=0.02) and in subcomponents of diet quality, as measured by the Healthy Eating Index-2005, and in fruit intake (servings/day, excludes juice) (p=0.02). Diet quality worsened more among controls than the intervention group at 1-year follow-up. Conclusions The adaptation of Hip-Hop to Health Jr. produced modest benefits in diet quality, but did not significantly impact weight gain trajectory. Not unlike other effectiveness trials, this real-world version delivered by Head Start teachers produced fewer benefits than the more rigorous efficacy trial. It is important to understand and build upon the lessons learned from these types of trials so that we can design, implement, and disseminate successful evidence-based programs more widely and effectively

  10. A fast-hopping 3-band CMOS frequency synthesizer for MB-OFDM UWB system

    Science.gov (United States)

    Yongzheng, Zheng; Lingli, Xia; Weinan, Li; Yumei, Huang; Zhiliang, Hong

    2009-09-01

    A fast-hopping 3-band (mode 1) multi-band orthogonal frequency division multiplexing ultra-wideband frequency synthesizer is presented. This synthesizer uses two phase-locked loops for generating steady frequencies and one quadrature single-sideband mixer for frequency shifting and quadrature frequency generation. The generated carriers can hop among 3432 MHz, 3960 MHz, and 4488 MHz. Implemented in a 0.13 μm CMOS process, this fully integrated synthesizer consumes 27 mA current from a 1.2 V supply. Measurement shows that the out-of-band spurious tones are below -50 dBc, while the in-band spurious tones are below -34 dBc. The measured hopping time is below 2 ns. The core die area is 1.0 × 1.8 mm2.

  11. Subunit organisation of in vitro reconstituted HOPS and CORVET multisubunit membrane tethering complexes.

    Directory of Open Access Journals (Sweden)

    Zhong Guo

    Full Text Available Biochemical and structural analysis of macromolecular protein assemblies remains challenging due to technical difficulties in recombinant expression, engineering and reconstitution of multisubunit complexes. Here we use a recently developed cell-free protein expression system based on the protozoan Leishmania tarentolae to produce in vitro all six subunits of the 600 kDa HOPS and CORVET membrane tethering complexes. We demonstrate that both subcomplexes and the entire HOPS complex can be reconstituted in vitro resulting in a comprehensive subunit interaction map. To our knowledge this is the largest eukaryotic protein complex in vitro reconstituted to date. Using the truncation and interaction analysis, we demonstrate that the complex is assembled through short hydrophobic sequences located in the C-terminus of the individual Vps subunits. Based on this data we propose a model of the HOPS and CORVET complex assembly that reconciles the available biochemical and structural data.

  12. Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities

    CERN Document Server

    Rodriguez, S R K; Sagnes, I; Gratiet, L Le; Galopin, E; Lemaitre, A; Bloch, J

    2016-01-01

    Bosons hopping across sites and interacting on-site are the essence of the Bose-Hubbard model (BHM). Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction, and decay of exciton polaritons --- mixed light-matter quasiparticles --- can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through effective polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields for polaritons in two-dimensional multicavity s...

  13. Optimal inhomogeneity for pairing in Hubbard systems with next-nearest-neighbor hopping

    Science.gov (United States)

    Wachtel, Gideon; Baruch, Shirit; Orgad, Dror

    2017-08-01

    Previous studies have shown that bipartite Hubbard systems with inhomogeneous hopping amplitudes can exhibit higher pair-binding energies than the uniform model. Here we examine whether this result holds for systems with a more generic band structure. To this end, we use exact diagonalization and the density matrix renormalization-group method to study the 4 ×4 Hubbard cluster and the two-leg Hubbard ladder with checkerboard-modulated nearest-neighbor hopping, t , and next-nearest-neighbor (diagonal) hopping, td. We find that the strongest pairing continues to occur at an intermediate level of inhomogeneity. While the maximal pair-binding energy is enhanced by a positive td/t , it is suppressed and appears at weaker repulsion strengths and lower hole concentrations when td/t is negative. We point out a possible connection between the pairing maximum and the magnetic properties of the system.

  14. Multi-hop Relaying: An End-to-End Delay Analysis

    KAUST Repository

    Chaaban, Anas

    2015-12-01

    The impact of multi-hopping schemes on the communication latency in a relay channel is studied. The main aim is to characterize conditions under which such schemes decrease the communication latency given a reliability requirement. Both decode-forward (DF) and amplify-forward (AF) with block coding are considered, and are compared with the point-to-point (P2P) scheme which ignores the relay. Latency expressions for the three schemes are derived, and conditions under which DF and AF reduce latency are obtained for high signal-to-noise ratio (SNR). Interestingly, these conditions are more strict when compared to the conditions under which the same multi-hopping schemes achieve higher long-term (information-theoretic) rates than P2P. It turns out that the relation between the sourcedestination SNR and the harmonic mean of the SNR’s of the channels to and from the relay dictates whether multi-hopping reduces latency or not.

  15. A fast-hopping 3-band CMOS frequency synthesizer for MB-OFDM UWB system

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Yongzheng; Xia Lingli; Li Weinan; Huang Yumei; Hong Zhiliang, E-mail: yumeihuang@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-09-15

    A fast-hopping 3-band (mode 1) multi-band orthogonal frequency division multiplexing ultra-wideband frequency synthesizer is presented. This synthesizer uses two phase-locked loops for generating steady frequencies and one quadrature single-sideband mixer for frequency shifting and quadrature frequency generation. The generated carriers can hop among 3432 MHz, 3960 MHz, and 4488 MHz. Implemented in a 0.13 {mu}m CMOS process, this fully integrated synthesizer consumes 27 mA current from a 1.2 V supply. Measurement shows that the out-of-band spurious tones are below -50 dBc, while the in-band spurious tones are below -34 dBc. The measured hopping time is below 2 ns. The core die area is 1.0 x 1.8 mm{sup 2}.

  16. Jumping and Hopping in Elite and Amateur Orienteering Athletes and Correlations to Sprinting and Running

    DEFF Research Database (Denmark)

    Hébert-Losier, Kim; Jensen, Kurt; Holmberg, Hans-Christer

    2014-01-01

    PURPOSE: Jumping and hopping are used to measure lower-body muscle power, stiffness, and stretch-shortening cycle utilization in sports, with several studies reporting correlations between such measures and sprinting and/or running abilities in athletes. Neither jumping and hopping nor correlations...... to road, path, and forest running and sprinting performance, as well as running economy, velocity at anaerobic threshold, and VO2peak from treadmill assessments. RESULTS: During SJs and CMJs, elites demonstrated superior relative peak forces, time-to-peak forces, and pre-stretch augmentation albeit lower......-stretch augmentation and forest running velocities. Pre-stretch augmentation and time-to-peak forces were moderately correlated to VO2peak. Correlations between running economy and jumping or hopping were small or trivial. CONCLUSIONS: Overall, our elites exhibited superior stretch-shortening cycle utilization...

  17. Topological Properties of Electrons in Honeycomb Lattice with Detuned Hopping Energy.

    Science.gov (United States)

    Wu, Long-Hua; Hu, Xiao

    2016-04-14

    Honeycomb lattice can support electronic states exhibiting Dirac energy dispersion, with graphene as the icon. We propose to derive nontrivial topology by grouping six neighboring sites of honeycomb lattice into hexagons and enhancing the inter-hexagon hopping energies over the intra-hexagon ones. We reveal that this manipulation opens a gap in the energy dispersion and drives the system into a topological state. The nontrivial topology is characterized by the index associated with a pseudo time-reversal symmetry emerging from the C6 symmetry of the hopping texture, where the angular momentum of orbitals accommodated on the hexagonal "artificial atoms" behaves as the pseudospin. The size of topological gap is proportional to the hopping-energy difference, which can be larger than typical spin-orbit couplings by orders of magnitude and potentially renders topological electronic transports available at high temperatures.

  18. Quando as ruas abrigam a arte: a cena hip hop no Recife (1980-2014)

    OpenAIRE

    Alves, Cristiano Nunes

    2015-01-01

    Operacionalizando a noção de cena, cara a estudo da produção artística nos lugares, analisa-se a espessura da cultura hip hop no Recife, desde os anos 1980 até os dias atuais. Desenvolve-se uma abordagem pautada no cotidiano enquanto dimensão geográfica, problematizando-se os nexos entre a cultura hip hop, a ação dos sujeitos nos lugares e o abrigo da comunicação na metrópole. Para esmiuçar a Cena Hip Hop em Recife, além do levantamento bibliográfico e documental sobre a temática, foram funda...

  19. Electronic transport of molecular nanowires by considering of electron hopping energy between the second neighbors

    Directory of Open Access Journals (Sweden)

    H Rabani

    2015-07-01

    Full Text Available In this paper, we study the electronic conductance of molecular nanowires by considering the electron hopping between the first and second neighbors with the help Green’s function method at the tight-binding approach. We investigate three types of structures including linear uniform and periodic chains as well as poly(p-phenylene molecule which are embedded between two semi-infinite metallic leads. The results show that in the second neighbor approximation, the resonance, anti-resonance and Fano phenomena occur in the conductance spectra of these structures. Moreover, a new gap is observed at edge of the lead energy band wich its width depends on the value of the electron hopping energy between the second neighbors. In the systems including intrinsic gap, this hopping energy shifts the gap in the energy spectra.

  20. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  1. Chemical composition of two samples of Humulus lupulus flowers (vernalized and wild hops

    Directory of Open Access Journals (Sweden)

    2017-11-01

    Full Text Available Background and objectives: Humulus lupulus, a plant belonging to the family Cannabaceae, is used as a medicinal plant with therapeutic applications in different nations. In this study, two samples of H. lupulus (vernalized and wild hops were selected for further analysis about differences of their essential oils. Methods: The essential oils from the flowers of two H. lupulus (vernalized and wild hops were achieved through hydrodistillation and analyzed via gas chromatography-mass spectrometry. Retention indices for all compounds were determined according to the kovats retention indices using n-alkanes series as standards. The components of the essential oils were identified by comparison of the retention indices and mass spectral data with those for the standards. Results: Analysis of the vernalized hops essential oil resulted in the identification of 64 components, representing 87.04 % of the total essential oil that principally contained β-caryophyllene (25.3%, β-bisabolole (16.7% and β-elemene (5.3%. In the case ofwild hops, 49 components were identified, representing 80.9% of theessential oil, among them β-bisabolole (35.2%, β-myrcene (13.3% and β-sesquiphellandrene (11.3% were the main compounds. Overall, both vernalized and wild hops possessed sesquiterpene hydrocarbons inhigher contents, followed bynon-terpenoid compounds, oxygenated sesquiterpenes and finally monoterpenoids in less amounts. Conclusion: Concerning the results of this study we found some similarities and differences among vernalized and wild hops and also in comparison with other species of the genus Humulus. Generally, mentioned similarities and differences might be attributed to both intrinsic and extrinsic factors affecting both the quality and quantity of the obtained essential oils.

  2. Hip-Hop Fight Club: Radical Theory, Education, and Practice in and beyond the Classroom

    Directory of Open Access Journals (Sweden)

    Jared A. Ball

    2013-10-01

    Full Text Available Hip-hop remains a viable method for the teaching of radical theory, emancipatory journalism and Africana Media Theory.  Fight Club is an emergent model that builds from existing hip-hop traditions of freetyle battling where critical thought and intellectual challenges of hueristic norms are upended.  This article argues in favor of bringing the Fight Club model into the classroom which allows for heightened student engagement and the inclusion of radical theoretical approaches to the study of mass media, communication and journalism.

  3. Asymmetric Exclusion Process with Constrained Hopping and Parallel Dynamics at a Junction

    Science.gov (United States)

    Liu, Mingzhe; Tuo, Xianguo; Li, Zhe; Yang, Jianbo

    In this article totally asymmetric simple exclusion process (TASEP) with constrained hopping and parallel dynamics at a junction is investigated using a mean-field approximation and Monte Carlo simulations. The constrained particle hopping probability r (r ≤ 1) at a junction may correspond to a delay caused by a driver choosing the right direction or a delay waiting for green traffic light in the real world. There are six stationary phases in the system, which can reflect free flow and congested traffic situations. Correlations at the junction point are investigated via simulations. It is observed that small r leads to stronger correlations. The theoretical results are agreement with computer simulations well.

  4. On the Performance Analysis of Dual-Hop FSO Fixed Gain Transmission Systems

    KAUST Repository

    Zedini, Emna

    2015-12-12

    Novel exact closed-form results for the end-to-end performance analysis of dual-hop free-space optical (FSO) fixed-gain relaying systems under heterodyne detection as well as intensity modulation with direct detection techniques in the presence of atmospheric turbulence as well as pointing errors are presented. By using dual-hop FSO relaying, we demonstrate a better system performance relative to the single FSO link. Numerical and Monte-Carlo simulation results are provided to verify the accuracy of the newly proposed results, and a perfect agreement is observed.

  5. An SDN-Based Fingerprint Hopping Method to Prevent Fingerprinting Attacks

    Directory of Open Access Journals (Sweden)

    Zheng Zhao

    2017-01-01

    Full Text Available Fingerprinting attacks are one of the most severe threats to the security of networks. Fingerprinting attack aims to obtain the operating system information of target hosts to make preparations for future attacks. In this paper, a fingerprint hopping method (FPH is proposed based on software-defined networks to defend against fingerprinting attacks. FPH introduces the idea of moving target defense to show a hopping fingerprint toward the fingerprinting attackers. The interaction of the fingerprinting attack and its defense is modeled as a signal game, and the equilibriums of the game are analyzed to develop an optimal defense strategy. Experiments show that FPH can resist fingerprinting attacks effectively.

  6. Dual-Hop Transmission Scheme Based on Hierarchical Modulation in Wireless Networks

    Science.gov (United States)

    Shin, Jeong-Chul; Song, Jin-Hyuk; Kim, Jee-Hoon; Song, Hyoung-Kyu

    Dual-hop wireless transmission is a technique by which the channel from the source to the destination is divided into two shorter links using relays. By using this transmission, the communications reliability is improved whereas the throughput might go down since the dual-hop transmission is performed by two times. In this letter, we propose a scheme that uses hierarchical modulation at the source and adaptive modulation based on cyclic redundancy check (CRC) code at the relays. The proposed scheme is evaluated in terms of the bit error rate (BER) and throughput performances.

  7. Characterization of Volatile Components from Hüller Bitterer Hop Variety Using In-Tube Extraction GC-MS Analysis

    National Research Council Canada - National Science Library

    Salanță, Liana Claudia; Tofană, Maria; Socaci, Sonia; Pop, Carmen; Pop, Anamaria; Cuceu, Ana

    2015-01-01

    .... The aim of this study was to characterize the Hüller Bitterer hop variety, during the development of hop cones, by analysis the composition of volatile oil using in-tube extraction gas chromatography–mass spectrometry (ITEX-GC–MS...

  8. Camp of Hip-Hop - kõigile kohustuslik / Mari Hiiemäe ; kommenteerinud Joel Juht

    Index Scriptorium Estoniae

    Hiiemäe, Mari

    2012-01-01

    Üheksandat korda toimuvast rahvusvahelisest tantsulaagrist ja tänavakultuuri tutvustavast noortelaagrist Camp of Hip-Hop, mis toimub Lääne Virumaal Käsmus. 28. juunil toimub kõigile huvilistele meelelahutusüritus Camp of Hip-Hop Championships, kus näitavad oma tantsuoskusi laagris osalejad ja maailmas tunnustatud koreograafid

  9. Hip-Hop Feminism: A Standpoint to Enhance the Positive Self-Identity of Black College Women

    Science.gov (United States)

    Henry, Wilma J.

    2010-01-01

    The popularity of hip-hop among young Black college women, coupled with the deluge of negative and positive messages in this culture regarding these women's identity, signals an opportunity for the arrival of a contemporary, culturally relevant epistemology--hip-hop feminism. Through the lens of Black feminist theory, this article explores hip-hop…

  10. Development of biological control of Tetranychus urticae (Acari:Tetranychidae) and Phorodon humuli (Hemiptera: Aphididae) in Oregon Hop yards

    Science.gov (United States)

    The temporal development of biological control of arthropod pests in perennial cropping systems is largely unreported. In this study, the development of biological control of twospotted spider mite, Tetranychus urticae Koch and hop aphid, Phorodon humuli (Schrank) in a new planting of hop in Oregon...

  11. An Educational Exploration of Homophobia and Sexism in Rap and Hip Hop: Homo-Thugs and Divas in da House

    Science.gov (United States)

    Chiu, Nicholas

    2005-01-01

    In this paper, the author explores the connections between hip hop and rap, sexism and homophobia, and children and teens. He describes the implications or potential consequences of sexism and homophobia within the music and media culture of hip hop and rap (with the focus on how it affects young viewers and fans in terms of gender [identity]…

  12. Culturally Relevant Teaching: Hip-Hop Pedagogy in Urban Schools. Counterpoints: Studies in the Postmodern Theory of Education. Volume 396

    Science.gov (United States)

    Prier, Darius D.

    2012-01-01

    "Culturally Relevant Teaching" centers hip-hop culture as a culturally relevant form of critical pedagogy in urban pre-service teacher education programs. In this important book, Darius D. Prier explores how hip-hop artists construct a sense of democratic education and pedagogy with transformative possibilities in their schools and communities. In…

  13. "You Don't Have to Claim Her": Reconstructing Black Femininity through Critical Hip-Hop Literacy

    Science.gov (United States)

    Kelly, Lauren Leigh

    2016-01-01

    This article explores the ways in which females who identify with hip-hop often develop and construct their identities in relation to media representations of blackness and femininity in hip-hop music and culture. In order for educators to support female students in constructing identities of empowerment and agency, they should be willing and able…

  14. Sista Girl Rock: Women of Colour and Hip-Hop Deejaying as Raced/Gendered Knowledge and Language

    Science.gov (United States)

    Craig, Todd; Kynard, Carmen

    2017-01-01

    This article seeks to introduce and situate a seldom-explored subject: the role and contribution of women hip-hop deejays in the testosterone-filled genre called hip-hop. Grounding the analysis in the interviews of six women deejays--Spinderella, Kuttin Kandi, Pam the Funkstress, Reborn, Shorty Wop and Natasha Diggs--"Sista Girl Rock"…

  15. Fresh Faces, New Places: Moving beyond Teacher-Researcher Perspectives in Hip-Hop-Based Education Research

    Science.gov (United States)

    Irby, Decoteau J.; Hall, H. Bernard

    2011-01-01

    Grounded in critical and culturally relevant theory, hip-hop-based education (HHBE) research documents the use of hip-hop in educational settings. Despite the richness of the emerging field, overreliance on teacher-researcher perspectives leaves much to be desired. Little is known of the extent and ways HHBE is used by nonresearching K-12…

  16. "They Wasn't Makin' My Kinda Music": A Hip-Hop Musician's Perspective on School, Schooling, and School Music

    Science.gov (United States)

    Kruse, Adam J.

    2016-01-01

    This article focuses on a hip-hop perspective of school, schooling, and school music. The study involves applications of ethnographic (including autoethnographic) techniques within the framework of a holistic multiple case study. One case is an adult amateur hip-hop musician named Terrence (pseudonym), and the other is myself (a traditionally…

  17. Arab Spring, "Favelas," Borders, and the Artistic Transnational Migration: Toward a Curriculum for a Global Hip-Hop Nation

    Science.gov (United States)

    Ibrahim, Awad

    2017-01-01

    Straddling between the purely political and the poetically artistic, I am arguing, is a Global Hip-Hop Nation (GHHN), which is yet to be charted and its cartography is yet to be demarcated. Taking two examples, the first a Hip-Hop song from within the Arab Spring and the second from the "favelas" in Brazil, my intent is to show what…

  18. Bridging Theory and Practice: Using Hip-Hop Pedagogy as a Culturally Relevant Approach in the Urban Science Classroom

    Science.gov (United States)

    Adjapong, Edmund S.

    2017-01-01

    This dissertation explores the context of urban science education as it relates to the achievement and engagement of urban youth. This study provides a framework for Hip-Hop Pedagogy, an approach to teaching and learning anchored in the creative elements of Hip-Hop culture, in STEM as an innovative approach to teaching and learning demonstrates…

  19. I Feel What He Was Doin': Responding to Justice-Oriented Teaching through Hip-Hop Aesthetics

    Science.gov (United States)

    Petchauer, Emery

    2011-01-01

    This study illustrates a set of learning activities designed from two hip-hop aesthetics and explores their use among a classroom of African American preservice teachers who graduated from urban school districts. Based on the two hip-hop aesthetics of kinetic consumption and autonomy/distance, the specific goal of these learning activities is to…

  20. Dialoguing, Cultural Capital, and Student Engagement: Toward a Hip Hop Pedagogy in the High School and University Classroom

    Science.gov (United States)

    Rodriguez, Louie F.

    2009-01-01

    Hip hop culture is typically excluded from conventional educational spaces within the U.S. Drawing on the experiences of an educator who works with urban high school students and university level pre- and in-service educators, this article examines the role of hip hop culture for student engagement in two settings--an alternative high school…

  1. "Dear Tupac, You Speak to Me": Recruiting Hip Hop as Curriculum at a School for Pregnant and Parenting Teens

    Science.gov (United States)

    Hallman, Heidi L.

    2009-01-01

    This article provides a rich representation of how in-school practices that recruit students' "out-of-school" literacies, such as hip hop, can be used as critical bridges in students' learning. Hip hop, conceptualized in this article as an "out-of-school" literacy, works as a vehicle for curricular change at Eastview School for Pregnant and…

  2. Multilingualism and Hip Hop Consumption in Nigeria: Accounting for the Local Acceptance of a Global Phenomenon Hip-Hop und Mehrsprachigkeit in Nigeria: Zur Erklärung der lokalen Akzeptanz eines globalen Phänomens

    Directory of Open Access Journals (Sweden)

    Olusegun Fariudeen Liadi

    2012-01-01

    Full Text Available Hip hop music has enjoyed global popularity and patronage on a level that has transcended that of most other music genres. It is perhaps due to the genre’s worldwide popularity that many forms of hip hop have sprung up across the globe. The Nigerian version of the music has been overwhelmingly accepted by a good number of youths in the country irrespective of class, religion and social status. However, there is some speculation as to what factors are responsible for the recent sudden boom in the popular consumption of this genre among the youth, since hip hop has been a feature of the Nigerian musical landscape since the 1980s. With the aid of qualitative data collection instruments – thirty in-depth interviews and six key informant interviews among hip hop fans and club DJs, respectively – the study establishes the centrality of multilingualism as a primary reason for the acceptance of hip hop among Nigerian youth.Hip-Hop-Musik ist weltweit in einem Maße populär, das die meisten anderen Musikrichtungen übertrifft. Vielleicht hat diese weltweite Beliebtheit dazu geführt, dass rund um den Globus unterschiedliche Formen des Hip-Hop aus dem Boden geschossen sind. Die nigerianische Version dieser Musikrichtung wird von einer überwältigenden Zahl Jugendlicher im Land angenommen, unabhängig von sozialem Status und Religionszugehörigkeit. Es wird jedoch darüber spekuliert, welche Faktoren den jüngsten plötzlichen Boom in dieser Musikrichtung erklären, denn Hip-Hop ist schon seit den 1980er Jahren Teil der nigerianischen Musiklandschaft. Mit Hilfe einer qualitativen Datenerhebung – 30 detaillierte Interviews sowie sechs Interviews mit Schlüsselpersonen unter Hip-Hop-Fans und Club-DJs – kann der Autor die Mehrsprachigkeit als wichtigsten Grund für die Akzeptanz des Hip-Hop unter nigerianischen Jugendlichen ermitteln.

  3. Corporeidade e sexualidade em dançarinos de rua: axé e hip hop Bodyness and sexuality of street dancers: axé and hip hop

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Cardoso

    2011-12-01

    Full Text Available Analisaram-se aspectos da corporeidade e sexualidade em dançarinos de hip hop e axé (35 homens e 49 mulheres comparativamente a indivíduos não-dançarinos expectadores da plateia (21 homens e 19 mulheres, via questionário anônimo. Os dançarinos de axé foram os mais satisfeitos com suas vidas sexuais, com as preliminares sexuais e os que mais gostavam de se masturbarem em relação aos de hip hop e plateia. Dançarinos do axé apresentaram uma sexualidade mais vinculada ao conhecimento corporal e conexões afetivas. Em ambos estilos, os dançarinos homens davam maior ênfase à genitália e a libido em relação aos aspectos da afetividade.We analyzed selected aspects of the bodyness and sexuality of hip hop and axé dancers (35 men and 49 women in comparison with non-dancer controls (21 men and 19 women through anonymous questionnaire. The axé dancers were the most satisfied with their sexual lives, with sexual preliminaries and who liked more to masturbate when compared with the hip hop dancers and controls. Axé dancers of both sexes presented a strong link between their sexuality and their corporal knowledge and affective connections. Men dancers were more focused in their genitals and gave stronger sexual emphasis to libido rather than affectivity.

  4. Nonadiabatic surface hopping Herman-Kluk semiclassical initial value representation method revisited: applications to Tully's three model systems.

    Science.gov (United States)

    Wu, Yinghua; Herman, Michael F

    2005-10-08

    The nonadiabatic surface hopping Herman-Kluk (HK) semiclassical initial value representation (SC-IVR) method for nonadiabatic problems is reformulated. The method has the same spirit as Tully's surface hopping technique [J. Chem. Phys. 93, 1061 (1990)] and almost keeps the same structure as the original single-surface HK SC-IVR method except that trajectories can hop to other surfaces according to the hopping probabilities and phases, which can be easily integrated along the paths. The method is based on a rather general nonadiabatic semiclassical surface hopping theory developed by Herman [J. Chem. Phys. 103, 8081 (1995)], which has been shown to be accurate to the first order in h and through all the orders of the nonadiabatic coupling amplitude. Our simulation studies on the three model systems suggested by Tully demonstrate that this method is practical and capable of describing nonadiabatic quantum dynamics for various coupling situations in very good agreement with benchmark calculations.

  5. Elastically cooperative activated barrier hopping theory of relaxation in viscous fluids. II. Thermal liquids.

    Science.gov (United States)

    Mirigian, Stephen; Schweizer, Kenneth S

    2014-05-21

    Building on the elastically collective nonlinear Langevin equation theory developed for hard spheres in Paper I, we propose and implement a quasi-universal theory for the alpha relaxation of thermal liquids based on mapping them to an effective hard sphere fluid via the dimensionless compressibility. The result is a zero adjustable parameter theory that can quantitatively address in a unified manner the alpha relaxation time over 14 or more decades. The theory has no singularities above zero Kelvin, and relaxation in the equilibrium low temperature limit is predicted to be of a roughly Arrhenius form. The two-barrier (local cage and long range collective elastic) description results in a rich dynamic behavior including apparent Arrhenius, narrow crossover, and deeply supercooled regimes, and multiple characteristic or crossover times and temperatures of clear physical meaning. Application of the theory to nonpolar molecules, alcohols, rare gases, and liquids metals is carried out. Overall, the agreement with experiment is quite good for the temperature dependence of the alpha time, plateau shear modulus, and Boson-like peak frequency for van der Waals liquids, though less so for hydrogen-bonding molecules. The theory predicts multiple growing length scales upon cooling, which reflect distinct aspects of the coupled local hopping and cooperative elastic physics. Calculations of the growth with cooling of an activation volume, which is strongly correlated with a measure of dynamic cooperativity, agree quantitatively with experiment. Comparisons with elastic, entropy crisis, dynamic facilitation, and other approaches are performed, and a fundamental basis for empirically extracted crossover temperatures is established. The present work sets the stage for addressing distinctive glassy phenomena in polymer melts, and diverse liquids under strong confinement.

  6. Effect of pH on the electrical properties and conducting mechanism of SnO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Periathai, R.Sudha [Department of Physics, Standard Fireworks Rajaratnam College for Women, Sivakasi 626123 (India); Abarna, S.; Hirankumar, G. [Centre for Scientific and Applied Research, PSN College of Engineering and Technology, Tirunelveli 627152 (India); Jeyakumaran, N. [Department of Physics, V.H.N. Senthikumara Nadar College, Virudhunagar 626001 (India); Prithivikumaran, N., E-mail: janavi_p@yahoo.com [Department of Physics, V.H.N. Senthikumara Nadar College, Virudhunagar 626001 (India)

    2017-03-15

    Semiconductor nanoparticles have attracted more interests because of their size-dependent optical and electrical properties.SnO{sub 2} is an oxygen-deficient n-type semiconductor with a wide band gap of 3.6 eV (300 K). It has many remarkable applications as sensors, catalysts, transparent conducting electrodes, anode material for rechargeable Li- ion batteries and optoelectronic devices. In the present work, the role of pH in determining the electrical and dielectric properties of SnO{sub 2} nanoparticles has been studied as a function of temperature ranging from Room temperature (RT) to 114 °C in the frequency range of 7 MHz to 50 mHz using impedance spectroscopic technique. The non linear behavior observed in the thermal dependence of the conductance of SnO{sub 2} nanoparticles is explained by means of the surface property of SnO{sub 2} nanoparticles where proton hopping mechanism is dealt with. Jonscher's power law has been fitted for the conductance spectra and the frequency exponent (“s” value) gives an insight about the ac conducting mechanism. The temperature dependence of electrical relaxation phenomenon in the material has been observed. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation.

  7. Auto-acetylation on K289 is not essential for HopZ1a-mediated plant defense suppression

    Directory of Open Access Journals (Sweden)

    Jose Sebastian Rufian

    2015-07-01

    Full Text Available The Pseudomonas syringae type III-secreted effector HopZ1a is a member of the HopZ / YopJ superfamily of effectors that triggers immunity in Arabidopsis. We have previously shown that HopZ1a suppresses both local (effector-triggered immunity, ETI and systemic immunity (systemic acquired resistance, SAR triggered by the heterologous effector AvrRpt2. HopZ1a has been shown to possess acetyltransferase activity, and this activity is essential to trigger immunity in Arabidopsis. HopZ1a acetyltransferase activity has been reported to require the auto-acetylation of the effector on a specific lysine (K289 residue. In this paper we analyze the relevance of autoacetylation of lysine residue 289 in HopZ1a ability to suppress plant defenses, and on the light of the results obtained, we also revise its relevance for HopZ1a avirulence activity. Our results indicate that, while the HopZ1aK289R mutant is impaired to some degree in its virulence and avirulence activities, is by no means phenotypically equivalent to the catalytically inactive HopZ1aC216A, since it is still able to trigger a defense response that induces detectable macroscopic HR and effectively protects Arabidopsis from infection, reducing growth of P. syringae within the plant. We also present evidence that the HopZ1aK289R mutant still displays virulence activities, partially suppressing both ETI and SAR.

  8. Hip-Hop--What's in It for the Academy? Self-Understanding, Pedagogy and Aesthetical Learning Processes in Everyday Cultural Praxis

    Science.gov (United States)

    Söderman, Johan; Sernhede, Ove

    2016-01-01

    Since hip-hop first appeared in New York over 35 years ago, it has been associated with social activism and education. Accordingly, it is not surprising that academic institutions in universities and K-12 schools are interested in hip-hop. In this article, we will highlight the "hip-hop academisation" and map out a new direction in a…

  9. All-electronic suppression of mode hopping noise in diode lasers

    DEFF Research Database (Denmark)

    Bager, L.

    1990-01-01

    A simple all-electronic stabilization scheme is presented for suppression of external-cavity mode-hopping noise in diode lasers. This excess noise is generated when the laser is subjected to optical feedback and may degrade the overall performance of optical systems including sensors. Suppression...

  10. Analysis of route availability in inter-working multi-hop wireless networks

    CSIR Research Space (South Africa)

    Salami, O

    2009-07-01

    Full Text Available In order to link a source-destination node pair in inter-working multi-hop wireless networks, links or routes must first be available. It is only after establishing the availability of links and routes between nodes that factors which affect...

  11. Implementing FORMS for the Monterey Bay Forecasting System Using HOPS and ROMS

    National Research Council Canada - National Science Library

    Gangopadhyay, Avijit

    2004-01-01

    ...) to implement the feature-oriented regional modeling system (FORMS) capabilities in the West Coast ROMS and HOPS modeling efforts for synoptic nowcast, forecast and 3D-VARS and ESSE-based assimilation in the Monterey Bay region, and (iii...

  12. Pharmacological profile of Xanthohumol, a Prenylated Flavonoid from Hops (Humulus lupulus)

    DEFF Research Database (Denmark)

    Liu, Ming; Hansen, Poul Erik; Wang, Genzhu

    2015-01-01

    The female inflorescences of hops (Humulus lupulus L.), a well-known bittering agent used in the brewing industry, have long been used in traditional medicines. Xanthohumol (XN) is one of the bioactive substances contributing to its medical applications. Among foodstuffs XN is found primarily in ...

  13. Critical Multimodal Hip Hop Production: A Social Justice Approach to African American Language and Literacy Practices

    Science.gov (United States)

    Turner, K. C. Nat; Hayes, Nini, Visaya; Way, Kate

    2013-01-01

    This article features key findings from a study that highlights the transformative impact of a pedagogical approach that employs Critical Multimodal Hip Hop Production (CMHHP). The study took place in an extended day program in a northern California public middle school among a group of 30, urban, African American, Chicano/a/Latino/a, and Asian…

  14. Sampling Memories: Using Hip-Hop Aesthetics to Learn from Urban Schooling Experiences

    Science.gov (United States)

    Petchauer, Emery

    2012-01-01

    This article theorizes and charts the implementation of a learning activity designed from the hip-hop aesthetic of sampling. The purpose of this learning activity was to enable recent urban school graduates to reflect upon their previous schooling experiences as a platform for future learning in higher education. This article illustrates what…

  15. Characterization of the Mammalian CORVET and HOPS Complexes and Their Modular Restructuring for Endosome Specificity

    NARCIS (Netherlands)

    van der Kant, Rik; Jonker, Caspar T. H.; Wijdeven, Ruud H.; Bakker, Jeroen; Janssen, Lennert; Klumperman, Judith; Neefjes, Jacques

    2015-01-01

    Trafficking of cargo through the endosomal system depends on endosomal fusion events mediated by SNARE proteins, Rab-GTPases, and multisubunit tethering complexes. The CORVET and HOPS tethering complexes, respectively, regulate early and late endosomal tethering and have been characterized in detail

  16. Uudised : Muusikal Lennonist kukkus läbi. Erkki Otsman. Hip-hop

    Index Scriptorium Estoniae

    2005-01-01

    Don Scardino lavastatud John Lennoni elu ja heliloomingu pinnalt sündinud muusikali etendamisest Ameerikas. Erkki Otsmani esinemisest 24. sept. Euroopa keelte päeva raames Krakovis. Los Angelese hip-hop-muusika plaadifirma Stones Throw sügisene Euroopa-turnee sel nädalal Tallinnas: Rock Café's 24. sept. esinevad MCd Wildchild, Declaime ja MED

  17. A Ratchet Lens: Black Queer Youth, Agency, Hip Hop, and the Black Ratchet Imagination

    Science.gov (United States)

    Love, Bettina L.

    2017-01-01

    This article explores the utilization of the theory of a Black ratchet imagination as a methodological perspective to examine the multiple intersections of Black and queer identity constructions within the space of hip hop. In particular, I argue for the need of a methodological lens that recognizes, appreciates, and struggles with the fluidity,…

  18. A Stochastic Geometry Model for Multi-hop Highway Vehicular Communication

    KAUST Repository

    Farooq, Muhammad Junaid

    2015-11-19

    Carrier sense multiple access (CSMA) protocol is standardized for vehicular communication to ensure a distributed and efficient communication between vehicles. However, several vehicular applications require efficient multi-hop information dissemination. This paper exploits stochastic geometry to develop a tractable and accurate modeling framework to characterize the multi-hop transmissions for vehicular networks in a multi-lane highway setup. In particular, we study the tradeoffs between per-hop packet forward progress, per-hop transmission success probability, and spatial frequency reuse (SFR) efficiency imposed by different packet forwarding schemes, namely, most forward with fixed radius (MFR), the nearest with forward progress (NFP), and the random with forward progress (RFP). We also define a new performance metric, denoted as the aggregate packet progress (APP), which is a dimensionless quantity that captures the aforementioned tradeoffs. To this end, the developed model reveals the interplay between the spectrum sensing threshold (th) of the CSMA protocol and the packet forwarding scheme. Our results show that, in contrary to ALOHA networks which always favor NFP, MFR may achieve the highest APP in CSMA networks if th is properly chosen.

  19. Characterization of resistance to powdery mildew in the Hop cultivars Newport and Comet

    Science.gov (United States)

    Hop powdery mildew, caused by Podosphaera macularis, is an important disease in the Northwestern U.S. Outbreaks of powdery mildew on cultivars previously resistant to the disease have been reported increasingly with the emergence of virulent pathogen strains capable of overcoming a commonly deployed...

  20. Polaron hopping mediated by nuclear tunnelling in semiconducting polymers at high carrier density

    NARCIS (Netherlands)

    Asadi, Kamal; Kronemeijer, Auke J.; Cramer, Tobias; Koster, L. Jan Anton; Blom, Paul W. M.; de Leeuw, Dago M.

    The transition rate for a single hop of a charge carrier in a semiconducting polymer is assumed to be thermally activated. As the temperature approaches absolute zero, the predicted conductivity becomes infinitesimal in contrast to the measured finite conductivity. Here we present a uniform