bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of model proton-coupled electron transfer reactions via the mixed quantum-classical Liouville approach
Authors: Shakib Farnaz A. , Hanna Gabriel
Published: July 2014

The nonadiabatic dynamics of model proton-coupled electron transfer (PCET) reactions is investigated for the first time using a surface-hopping algorithm based on the solution of the mixed quantum-classical Liouville equation (QCLE). This method provides a rigorous treatment of quantum coherence/decoherence effects in the dynamics of mixed quantum-classical systems, which is lacking in the molecular dynamics with quantum transitions surface-hopping approach commonly used for simulating PCET reactions. Within this approach, the protonic and electronic coordinates are treated quantum mechanically and the solvent coordinate evolves classically on both single adiabatic surfaces and on coherently coupled pairs of adiabatic surfaces. Both concerted and sequential PCET reactions are studied in detail under various subsystem-bath coupling conditions and insights into the dynamical principles underlying PCET reactions are gained. Notably, an examination of the trajectories reveals that the system spends the majority of its time on the average of two coherently coupled adiabatic surfaces, during which a phase enters into the calculation of an observable. In general, the results of this paper demonstrate the applicability of QCLE-based surface-hopping dynamics to the study of PCET and emphasize the importance of mean surface evolution and decoherence effects in the calculation of PCET rate constants.
Unusual swelling of a polymer in a bacterial bath
Authors: Kaiser A. , Löwen H.
Published: July 2014

The equilibrium structure and dynamics of a single polymer chain in a thermal solvent is by now well-understood in terms of scaling laws. Here, we consider a polymer in a bacterial bath, i.e., in a solvent consisting of active particles which bring in nonequilibrium fluctuations. Using computer simulations of a self-avoiding polymer chain in two dimensions which is exposed to a dilute bath of active particles, we show that the Flory-scaling exponent is unaffected by the bath activity provided the chain is very long. Conversely, for shorter chains, there is a nontrivial coupling between the bacteria intruding into the chain which may stiffen and expand the chain in a nonuniversal way. As a function of the molecular weight, the swelling first scales faster than described by the Flory exponent, then an unusual plateau-like behaviour is reached and finally a crossover to the universal Flory behaviour is observed. As a function of bacterial activity, the chain end-to-end distance exhibits a pronounced non-monotonicity. Moreover, the mean-square displacement of the center of mass of the chain shows a ballistic behaviour at intermediate times as induced by the active solvent. Our predictions are verifiable in two-dimensional bacterial suspensions and for colloidal model chains exposed to artificial colloidal microswimmers.
Microfabricated alkali vapor cell with anti-relaxation wall coating
Authors: Straessle R. , Pellaton M. , Affolderbach C. , Pétremand Y. , Briand D. , Mileti G. , de Rooij N. F.
Published: July 2014

We present a microfabricated alkali vapor cell equipped with an anti-relaxation wall coating. The anti-relaxation coating used is octadecyltrichlorosilane and the cell was sealed by thin-film indium-bonding at a low temperature of 140 °C. The cell body is made of silicon and Pyrex and features a double-chamber design. Depolarizing properties due to liquid Rb droplets are avoided by confining the Rb droplets to one chamber only. Optical and microwave spectroscopy performed on this wall-coated cell are used to evaluate the cell's relaxation properties and a potential gas contamination. Double-resonance signals obtained from the cell show an intrinsic linewidth that is significantly lower than the linewidth that would be expected in case the cell had no wall coating but only contained a buffer-gas contamination on the level measured by optical spectroscopy. Combined with further experimental evidence this proves the presence of a working anti-relaxation wall coating in the cell. Such cells are of interest for applications in miniature atomic clocks, magnetometers, and other quantum sensors.
The impact of laser plasma interactions on three-dimensional drive symmetry in inertial confinement fusion implosions
Authors: Peterson J. L. , Michel P. , Thomas C. A. , Town R. P. J.
Published: July 2014

Achieving symmetric hohlraum radiation drive is an important aspect of indirectly driven inertial confinement fusion experiments. However, when experimentally delivered laser powers deviate from ideal conditions, the resultant radiation field can become asymmetric. Two situations in which this may arise are random uncorrelated fluctuations, in as-delivered laser power and laser beams that do not participate in the implosion (either intentionally or unintentionally). Furthermore, laser plasma interactions in the hohlraum obfuscate the connection between laser powers and radiation drive. To study the effect of these situations on drive symmetry, we develop a simplified model for crossed-beam energy transfer, laser backscatter, and plasma absorption that can be used in conjunction with view factor calculations to expediently translate laser powers into three-dimensional capsule flux symmetries. We find that crossed-beam energy transfer can alter both the statistical properties of uncorrelated laser fluctuations and the impact of missing laser beams on radiation symmetry. A method is proposed to mitigate the effects of missing laser beams.
Electromagnetic modeling of the energy distribution of a metallic cylindrical parabolic reflector covered with a magnetized plasma layer
Authors: Niknam A. R. , Khajehmirzaei M. R. , Davoudi-Rahaghi B. , Rahmani Z. , Jazi B. , Abdoli-Arani A.
Published: July 2014

The energy distribution along the focal axis of a long metallic cylindrical parabolic reflector with a plasma layer on its surface in the presence of an external magnetic field is investigated. The effects of some physical parameters, such as the plasma frequency, the wave frequency and the thickness of plasma layer on the energy distribution and the reflected and transmitted electromagnetic fields, are simulated. These investigations for both S- and P-polarizations have been done separately. It is found that the maximum value of the reflected intensity increases by increasing the incident wave frequency and by decreasing the plasma layer thickness and the plasma frequency for both polarizations. Furthermore, the results show that the increase of the magnetic field strength can cause an increase in the reflected intensity for S-polarization and a slight decrease for P-polarization.
Eddy current effects in the magnetization dynamics of ferromagnetic metal nanoparticles
Authors: Denisov S. I. , Lyutyy T. V. , Pedchenko B. O. , Babych H. V.
Published: July 2014

We develop an analytical model for describing the magnetization dynamics in ferromagnetic metal nanoparticles, which is based on the coupled system of the Landau-Lifshitz-Gilbert (LLG) and Maxwell equations. By solving Maxwell's equations in the quasi-static approximation and finding the magnetic field of eddy currents, we derive the closed LLG equation for the magnetization that fully accounts for the effects of conductivity. We analyze the difference between the LLG equations in metallic and dielectric nanoparticles and show that these effects can strongly influence the magnetization dynamics. As an example illustrating the importance of eddy currents, the phenomenon of precessional switching of magnetization is considered.
Charge and magnetic states of Mn-, Fe-, and Co-doped monolayer MoS2
Authors: Lin Xianqing , Ni Jun
Published: July 2014

First-principles calculations have been performed to investigate the electronic and magnetic properties of monolayer MoS2 substitutionally doped with Mn, Fe, and Co in possible charge states (q). We find that the Mn, Fe, and Co dopants substituting for a Mo atom in monolayer MoS2 (Mn@Mo, Fe@Mo, and Co@Mo) are all magnetic in their neutral and charge states except in the highest positive charge states. Mn@Mo, Fe@Mo, and Co@Mo have the same highest negative charge states of q=−2 for chemical potential of electron just below the conduction band minimum, which corresponds to the electron doping. In the q=−2 state, Mn@Mo has a much larger magnetic moment than its neutral state with the antiferromagnetic coupling between the Mn dopant and its neighboring S atoms maintained, while Fe@Mo and Co@Mo have equal or smaller magnetic moments than their neutral states. The possible charge states of Mn@Mo, Fe@Mo, and Co@Mo and the variation of the magnetic moments for different dopants and charge states are due to the change of the occupation and energy of the anti-bonding defect levels in the band gap. The rich magnetic properties of the neutral and charge states suggest possible realization of the substitutionally Mn-, Fe-, and Co-doped monolayer MoS2 as dilute magnetic semiconductors.
In-situ photoluminescence imaging for passivation-layer etching process control for photovoltaics
Authors: Lee J. Z. , Michaelson L. , Munoz K. , Tyson T. , Gallegos A. , Sullivan J. T. , Buonassisi T.
Published: July 2014

Light-induced plating (LIP) of solar-cell metal contacts is a scalable alternative to silver paste. However, LIP requires an additional patterning step to create openings in the silicon nitride (SiNx) antireflection coating (ARC) layer prior to metallization. One approach to pattern the SiNx is masking and wet chemical etching. In-situ real-time photoluminescence imaging (PLI) is demonstrated as a process-monitoring method to determine when SiNx has been fully removed during etching. We demonstrate that the change in PLI signal intensity during etching is caused by a combination of (1) decreasing light absorption from the reduction in SiNx ARC layer thickness and (2) decreasing surface lifetime as the SiNx/Si interface transitions to an etch-solution/Si. Using in-situ PLI to guide the etching process, we demonstrate a full-area plated single-crystalline silicon device. In-situ PLI has the potential to be integrated into a commercial processing line to improve process control and reliability.
Tunable graphene saturable absorber with cross absorption modulation for mode-locking in fiber laser
Authors: Sheng Qi-Wen , Feng Ming , Xin Wei , Guo Hao , Han Tian-Yu , Li Yi-Gang , Liu Yan-Ge , Gao Feng , Song Feng , Liu Zhi-Bo , Tian Jian-Guo
Published: July 2014

Graphene saturable absorbers (GSAs) have been widely applied in ultra-fast mode-locked fiber lasers. Thanks to the broadband advantage of graphene, we theoretically and experimentally demonstrate the variation of the modulation depth of GSA by employing the effect of cross absorption modulation. This method provides an easy and efficient way to modulate the characteristics of GSA. By varying the modulation power, we realize an all-fiber fundamental mode-locked fiber laser and a harmonic mode-locked fiber laser with tunable output pulse width. Results show that the output pulse widths of the two fiber lasers can be tuned more than 40%, and the lasers have high wide application potential on nonlinear optical bio-imaging and offer an advantageous front end for extreme-power laser technologies.
Electronic and magnetic properties of (1 1 1)-oriented CoCr2O4 epitaxial thin film
Authors: Liu Xiaoran , Kareev M. , Cao Yanwei , Liu Jian , Middey S. , Meyers D. , Freeland J. W. , Chakhalian J.
Published: July 2014

We report on the fabrication of high quality (1 1 1)-oriented ferrimagnetic normal spinel CoCr2O4 epitaxial thin films on single crystal Al2O3 substrates. The structural, electronic, and magnetic properties were characterized by in-situ reflection high energy electron diffraction, atomic force microscopy, X-ray diffraction, X-ray photoemission spectroscopy, dc magnetization measurement, and element resolved resonant X-ray magnetic scattering. The comprehensive characterization reveals that no disorder in the cation distribution or multivalency issue is present in the samples. As a result, Kagomé and triangular layers are naturally formed via this specific growth approach. These findings offer a pathway to fabricate two dimensional Kagomé heterostructures with exotic quantum many-body phenomena by means of geometrical design.
Donor characterization in ZnO by thermally stimulated luminescence
Authors: Ji Jianfeng , Boatner L. A. , Selim F. A.
Published: July 2014

Low temperature thermo-luminescence (TL) has been applied to measurements of the ionization energy of donors in ZnO. Three hydrogen-related donors were characterized with ionization energies of 36, 47, and 55 meV—values that are in complete agreement with previous reports. The donor types can be “switched” by relevant thermal treatments. This work shows that TL can be used to measure the donor energies in luminescent semiconductors in general. This approach can be particularly useful for thin-film investigations when the results of Hall-effect measurements are obscured by contributions from conductive interfaces or substrates.
Generation of strong terahertz fields exceeding 8 MV/cm at 1 kHz and real-time beam profiling
Authors: Oh T. I. , Yoo Y. J. , You Y. S. , Kim K. Y.
Published: July 2014

We demonstrate high-field (>8 MV/cm) terahertz generation at a high-repetition-rate (1 kHz) via two-color laser filamentation. Here, we use a cryogenically cooled femtosecond laser amplifier capable of producing 30 fs, 15 mJ pulses at 1 kHz as a driver, along with a combination of a thin dual-wavelength half-waveplate and a Brewster-angled silicon window to enhance terahertz generation and transmission. We also introduce a cost-effective, uncooled microbolometer camera for real-time terahertz beam profiling with two different modes.
A proposal for Coulomb assisted laser cooling of piezoelectric semiconductors
Authors: Nia Iman Hassani , Mohseni Hooman
Published: July 2014

Anti-Stokes laser cooling of semiconductors as a compact and vibration-free method is very attractive. While it has achieved significant milestones, increasing its efficiency is highly desirable. The main limitation is the lack of the pristine material quality with high luminescence efficiency. Here, we theoretically demonstrate that the Coulomb interaction among electrons and holes in piezoelectric heterostructures could lead to coherent damping of acoustic phonons; rendering a significantly higher efficiency that leads to the possibility of cooling a broad range of semiconductors.
Controls on the spatial pattern of wildfire ignitions in Southern California
Authors: Faivre Nicolas , Jin Yufang , Goulden Michael L. , Randerson James T.
Published: July 2014

Wildfire ignition requires a combination of an open spark, and suitable weather and fuel conditions. Models of fire occurrence and burned area provide a good understanding of the physical and climatic factors that constrain and promote fire spread and recurrence, but information on how humans influence ignition patterns is still lacking at a scale compatible with integrated fire management. We investigated the relative importance of the physical, climatic and human factors regulating ignition probability across Southern California’s National Forests. A 30-year exploratory analysis of one-way relationships indicated that distance to a road, distance to housing and topographic slope were the major determinants of ignition frequency. We used logistic and Poisson regression analyses to model ignition occurrence and frequency as a function of the dominant covariates. The resulting models explained ~70% of the spatial variability in ignition likelihood and 45% of the variability in ignition frequency. In turn, predicted ignition probability contributed to some of the spatial variability in burned area, particularly for summer fires. These models may enable estimates of fire ignition risk for the broader domain of Southern California and how this risk may change with future population and housing development. Our spatially explicit predictions may also be useful for strategic fire management in the region.
The changing face of cognitive gender differences in Europe
Authors: Weber Daniela , Skirbekk Vegard , Freund Inga , Herlitz Agneta
Published: July 2014

Significance

Results showing that gender differences in mathematics and science are smaller in countries with higher gender equality have led researchers to conclude that cognitive gender differences are decreasing as a function of increased gender equality. Instead, we find that improved living conditions and less gender-restricted educational opportunities are associated with increased gender differences favoring women in some cognitive functions and decreases or elimination of gender differences in other cognitive abilities. Our results suggest that these changes take place as a result of women gaining more than men from societal improvements over time, thereby increasing their general cognitive ability more than men.
Quantifying the semantics of search behavior before stock market moves
Authors: Curme Chester , Preis Tobias , Stanley H. Eugene , Moat Helen Susannah
Published: July 2014

Significance

Internet search data may offer new possibilities to improve forecasts of collective behavior, if we can identify which parts of these gigantic search datasets are relevant. We introduce an automated method that uses data from Google and Wikipedia to identify relevant topics in search data before large events. Using stock market moves as a case study, our method successfully identifies historical links between searches related to business and politics and subsequent stock market moves. We find that the predictive value of these search terms has recently diminished, potentially reflecting increasing incorporation of Internet data into automated trading strategies. We suggest that extensions of these analyses could help draw links between search data and a range of other collective actions.
The role of PI3K/AKT-related PIP5K1α and the discovery of its selective inhibitor for treatment of advanced prostate cancer
Authors: Semenas Julius , Hedblom Andreas , Miftakhova Regina R. , Sarwar Martuza , Larsson Rikard , Shcherbina Liliya , Johansson Martin E. , Härkönen Pirkko , Sterner Olov , Persson Jenny L.
Published: July 2014

Significance

Prostate cancer is the most common malignancy and the third leading cancer-related cause of death among men of the Western world. Treatment options at advanced stages of the disease are scarce, and better therapies are in urgent need. In our study, we show that the clinically relevant lipid kinase phosphatidylinositol-4-phosphate 5-kinase-α (PIP5Kα) plays an important role in cancer cell invasion and survival by regulating the PI3K/AKT/androgen receptor pathways. Elevated levels of PIP5K1α contribute to cancer cell proliferation, survival, and invasion. In this context we introduce a newly developed compound, ISA-2011B, with promising anticancer effects by inhibiting the PIP5K1α-associated AKT pathways. Conclusively, we propose that PIP5K1α may be used as a potential therapeutic target for treatment of advanced prostate cancer.
Hypothalamic prolyl endopeptidase (PREP) regulates pancreatic insulin and glucagon secretion in mice
Authors: Kim Jung Dae , Toda Chitoku , D’Agostino Giuseppe , Zeiss Caroline J. , DiLeone Ralph J. , Elsworth John D. , Kibbey Richard G. , Chan Owen , Harvey Brandon K. , Richie Christopher T. , Savolainen Mari , Myöhänen Timo , Jeong Jin Kwon , Diano Sabrina
Published: July 2014

Significance

The ventromedial nucleus of the hypothalamus (VMH) plays an important role in the regulation of glucose metabolism. Here we show that prolyl endopeptidase (PREP), a serine protease, is expressed in the VMH where it functions to regulate glucose-induced insulin secretion. Experimental knockdown of central PREP induced impairment of VMH glucose sensing, resulting in reduced insulin and increased glucagon secretion by the pancreas via altered sympathetic outflow. Our data reveal PREP as a new hypothalamic player in the control of glucose homeostasis.
Bacillus subtilischromosome organization oscillates between two distinct patterns
Authors: Wang Xindan , Montero Llopis Paula , Rudner David Z.
Published: July 2014

Significance

In bacteria, faithful and efficient DNA segregation is intimately linked to the spatial organization of the chromosome. Two distinct organization patterns have been described for bacterial chromosomes (ori-terand left-ori-right) that appear to arise from distinct segregation mechanisms. Here, we show that theBacillus subtilischromosome oscillates between them during a replication–segregation cycle. Our data further suggest that the highly conserved condensin complex and theparABSpartitioning system function as the core components that underlie these alternating patterns. We propose that this oscillatory cycle enhances the efficiency of DNA replication and sister chromosome segregation and provides a unifying model for the diverse patterns of chromosome organization observed in bacteria.
Early remodeling of the neocortex upon episodic memory encoding
Authors: Bero Adam W. , Meng Jia , Cho Sukhee , Shen Abra H. , Canter Rebecca G. , Ericsson Maria , Tsai Li-Huei
Published: July 2014

Significance

Prevailing theory suggests that episodic memory encoding is subserved by early remodeling of hippocampal circuits, whereas remodeling of the neocortex occurs weeks to months later to promote long-term memory storage and recall. Herein, we show that episodic memory encoding elicits early remodeling of neocortical circuits in mouse brain. Specifically, memory encoding triggered a transcriptomic program in the medial prefrontal cortex (mPFC) that was accompanied by rapid structural and functional plasticity of local synaptic circuits. Using optogenetics to examine the real-time contribution of the mPFC to memory encoding, we found that activity of excitatory mPFC neurons is required for hippocampal activation and formation of long-term memory. These data have important implications for understanding memory processing in healthy and diseased brain states.
Sorting Nexin 27 regulates basal and activity-dependent trafficking of AMPARs
Authors: Hussain Natasha K. , Diering Graham H. , Sole Jonathan , Anggono Victor , Huganir Richard L.
Published: July 2014

Significance

AMPA-type glutamate receptors (AMPARs) are principal regulators of synaptic signaling in the brain. Modulation of AMPA receptor activity, whether through changes in surface expression or conductance, contributes significantly to the dynamic nature of neuronal networks. AMPA receptor mediated-synaptic plasticity is thought to underlie learning and memory, as aberrant AMPAR trafficking contributes to impaired plasticity and to memory deficits. We demonstrate that the membrane trafficking and sorting protein, SNX27, regulates basal and activity dependent targeting of AMPA receptors to the neuronal surface. Elucidating the mechanism of receptor sorting mediated by SNX27 will not only further our understanding AMPAR-mediated changes in synaptic plasticity, but may ultimately shed light on the molecular mechanisms that govern learning.
Cyclin-dependent kinases regulate lysosomal degradation of hypoxia-inducible factor 1α to promote cell-cycle progression
Authors: Hubbi Maimon E. , Gilkes Daniele M. , Hu Hongxia , Kshitiz  , Ahmed Ishrat , Semenza Gregg L.
Published: July 2014

Significance

Hypoxia-inducible factor 1α (HIF-1α) is required for adaptive changes to low oxygen levels, which include a reduced rate of cell division. However, many cell types continue to proliferate under hypoxic conditions. Here, we show that cyclin-dependent kinases 1 and 2 physically and functionally interact with HIF-1α, inhibiting and promoting its degradation by lysosomes, respectively. Cancer cells that proliferate under hypoxia failed to do so when treated with lysosome inhibitors. Our studies reveal that HIF-1α levels are coupled to phases of the cell cycle through lysosomal degradation and identify a novel role for the lysosome as a regulator of cell-cycle progression under hypoxic conditions.
Radial intercalation is regulated by the Par complex and the microtubule-stabilizing protein CLAMP/Spef1
Authors: Werner Michael E. , Mitchell Jennifer W. , Putzbach William , Bacon Elizabeth , Kim Sun K. , Mitchell Brian J.
Published: July 2014

The directed movement of cells is critical for numerous developmental and disease processes. A developmentally reiterated form of migration is radial intercalation; the process by which cells move in a direction orthogonal to the plane of the tissue from an inner layer to an outer layer. We use the radial intercalation of cells into the skin of Xenopus laevis embryos as a model to study directed cell migration within an epithelial tissue. We identify a novel function for both the microtubule-binding protein CLAMP and members of the microtubule-regulating Par complex during intercalation. Specifically, we show that Par3 and aPKC promote the apical positioning of centrioles, whereas CLAMP stabilizes microtubules along the axis of migration. We propose a model in which the Par complex defines the orientation of apical migration during intercalation and in which subcellular localization of CLAMP promotes the establishment of an axis of microtubule stability required for the active migration of cells into the outer epithelium.
TPX2 levels modulate meiotic spindle size and architecture in Xenopus egg extracts
Authors: Helmke Kara J. , Heald Rebecca
Published: July 2014

The spindle segregates chromosomes in dividing eukaryotic cells, and its assembly pathway and morphology vary across organisms and cell types. We investigated mechanisms underlying differences between meiotic spindles formed in egg extracts of two frog species. Small Xenopus tropicalis spindles resisted inhibition of two factors essential for assembly of the larger Xenopus laevis spindles: RanGTP, which functions in chromatin-driven spindle assembly, and the kinesin-5 motor Eg5, which drives antiparallel microtubule (MT) sliding. This suggested a role for the MT-associated protein TPX2 (targeting factor for Xenopus kinesin-like protein 2), which is regulated by Ran and binds Eg5. Indeed, TPX2 was threefold more abundant in X. tropicalis extracts, and elevated TPX2 levels in X. laevis extracts reduced spindle length and sensitivity to Ran and Eg5 inhibition. Higher TPX2 levels recruited Eg5 to the poles, where MT density increased. We propose that TPX2 levels modulate spindle architecture through Eg5, partitioning MTs between a tiled, antiparallel array that promotes spindle expansion and a cross-linked, parallel architecture that concentrates MTs at spindle poles.
Tracking S4 movement by gating pore currents in the bacterial sodium channel NaChBac
Authors: Gamal El-Din Tamer M. , Scheuer Todd , Catterall William A.
Published: July 2014

Voltage-gated sodium channels mediate the initiation and propagation of action potentials in excitable cells. Transmembrane segment S4 of voltage-gated sodium channels resides in a gating pore where it senses the membrane potential and controls channel gating. Substitution of individual S4 arginine gating charges (R1–R3) with smaller amino acids allows ionic currents to flow through the mutant gating pore, and these gating pore currents are pathogenic in some skeletal muscle periodic paralysis syndromes. The voltage dependence of gating pore currents provides information about the transmembrane position of the gating charges as S4 moves in response to membrane potential. Here we studied gating pore current in mutants of the homotetrameric bacterial sodium channel NaChBac in which individual arginine gating charges were replaced by cysteine. Gating pore current was observed for each mutant channel, but with different voltage-dependent properties. Mutating the first (R1C) or second (R2C) arginine to cysteine resulted in gating pore current at hyperpolarized membrane potentials, where the channels are in resting states, but not at depolarized potentials, where the channels are activated. Conversely, the R3C gating pore is closed at hyperpolarized membrane potentials and opens with channel activation. Negative conditioning pulses revealed time-dependent deactivation of the R3C gating pore at the most hyperpolarized potentials. Our results show sequential voltage dependence of activation of gating pore current from R1 to R3 and support stepwise outward movement of the substituted cysteines through the narrow portion of the gating pore that is sealed by the arginine side chains in the wild-type channel. This pattern of voltage dependence of gating pore current is consistent with a sliding movement of the S4 helix through the gating pore. Through comparison with high-resolution models of the voltage sensor of bacterial sodium channels, these results shed light on the structural basis for pathogenic gating pore currents in periodic paralysis syndromes.
Groups with graphical 𝐶(6) and 𝐶(7) small cancellation presentations
Authors: Gruber Dominik
Published: July 2014

We extend fundamental results of small cancellation theory to groups whose presentations satisfy the generalizations of the classical

C
(
6
)

C(6)

and

C
(
7
)

C(7)

conditions in graphical small cancellation theory. Using these graphical small cancellation conditions, we construct lacunary hyperbolic groups and groups that coarsely contain prescribed infinite sequences of finite graphs. We prove that groups given by (possibly infinite) graphical

C
(
7
)

C(7)

presentations contain non-abelian free subgroups.
Simultaneous Estimation of Risk and Time Preferences among Small‐scale Cattle Farmers in West Africa
Authors: Liebenehm Sabine , Waibel Hermann
Published: July 2014

This article reports results from economic field experiments with cattle‐dependent small‐scale farmers in West Africa. We simultaneously estimate both risk and time preferences and examine how demographic and socio‐economic characteristics are correlated with each preference. The empirical basis for our analysis is a panel data survey of 211 households conducted in Mali and Burkina Faso in 2007 and 2011, and economic experiments conducted with the heads of these households in 2011. The theoretical basis for our analysis is a discounted utility model. We apply prospect theory and quasi‐hyperbolic discounting to estimate the present values of future utility streams. We apply a maximum likelihood approach to jointly estimate risk and time preferences, and to investigate the correlations among the preference parameters and observable characteristics. We find that, on average, the West African cattle farmer is generally more risk averse and more patient than similarly‐situated respondents from Asia. Additionally, risk and time preferences are correlated with wealth, education, and religion. We find that constraints in wealth and education are associated with greater risk aversion and impatience. Furthermore, time spent in a Koranic school is positively related to the overweighting of small probabilities, greater risk‐taking behavior, and patience.
Active Surveillance and Decolonization Without Isolation Is Effective in Preventing Methicillin-Resistant Staphylococcus aureus Transmission in the Psychiatry Units
Authors: Das Sanchita , Harazin Maureen , Wright Marc Oliver , Dusich Irene , Robicsek Ari , Peterson Lance R.
Published: July 2014

Background.  Control of methicillin-resistant Staphylococcus aureus (MRSA) is difficult in select populations. We used molecular typing to study the effect of universal surveillance and decolonization of carriers, without isolation, on MRSA transmission in a specialized unit.

Methods.  Patients admitted to the unit were screened for nasal MRSA at admission and discharge. Those who acquired MRSA during their stay were identified and linked to carriers with shared time in unit. Molecular typing of isolates was performed to identify transmission.

Results.  Of 3285 admissions, 82% were tested for MRSA nasal carriage; the discharge screening compliance was 64.7%. Admission prevalence was 2.3% among patients screened, and 7 (0.42%) acquired nasal MRSA during their stay. All patients who acquired MRSA shared time in the unit with a colonized patient. There were 3.9 MRSA acquisitions per 1000 at-risk days. Isolates from 5 patients that acquired MRSA during their stay as well as their potential donors (11 donor: recipient patient pairs) were available for typing. Pulsed-field gel electrophoresis matched 1 acquisition isolate to a colonized patient isolate. There were no MRSA infections during the study period.

Conclusions.  Despite less than perfect nasal screening compliance and exemption from traditional isolation precautions, acquisition of MRSA was 0.42% in this patient population over a course of 4.75 years, including a single case of acquisition, genetically similar to a known potential donor source. Screening for MRSA colonization and decolonizing of carriers was sufficient in reducing transmission in this vulnerable population.
Improved specimen recovery in tensile split Hopkinson bar
Authors: Isakov Matti , Hiermaier Stefan , Kuokkala Veli-Tapani
Published: July 2014

This paper presents an improved specimen recovery method for the tensile split Hopkinson bar (TSHB) technique. The method is based on the trapping of residual stress waves with the use of momentum trap bars. As is well known, successful momentum trapping in TSHB is highly sensitive to experimental uncertainties, especially on the incident bar side of the set-up. However, as is demonstrated in this paper, significant improvement in the reliability of specimen recovery is obtained by using two momentum trap bars in contact with the incident bar. This makes the trapping of the reflected wave insensitive to striker speed and removes the need for a precision set gap between the incident bar and the momentum trap.
Salimicrobium jeotgali sp. nov., isolated from salted, fermented seafood
Authors: Choi Eun Jin , Jin Hyun Mi , Kim Kyung Hyun , Jeon Che Ok
Published: July 2014

A Gram-staining-positive, aerobic, motile bacterium, designated strain MJ3T, was isolated from myeolchi-jeot (anchovy jeotgal), a traditional fermented seafood in South Korea. Cells were non-endospore-forming cocci showing catalase- and oxidase-positive reactions. Growth of strain MJ3T was observed at 15–45 °C (optimum, 30 °C), at pH 6.0–9.0 (optimum, pH 7.0–8.0) and in the presence of 1–24 % (w/v) NaCl (optimum, 10 % NaCl). Phylogenetic inference based on 16S rRNA gene sequences showed that strain MJ3T formed a tight phyletic lineage with members of the genus

Salimicrobium

. Strain MJ3T was related most closely to

Salimicrobium salexigens

29CMIT,

Salimicrobium album

DSM 20748T,

Salimicrobium flavidum

ISL-25T,

Salimicrobium luteum

BY-5T and

Salimicrobium halophilum

DSM 4771T, with similarities of 98.8 %, 98.7 %, 98.6 %, 98.4 % and 98.3 %, respectively. However, the DNA–DNA relatedness values between strain MJ3T (KF732837) and

S. salexigens

DSM 22782T,

S. album

DSM 20748T,

S. flavidum

DSM 23127T,

S. luteum

KCTC 3989T and

S. halophilum

JCM 12305T were 60±5.4 %, 58.5±6.5 %, 43.6±5.5 %, 37.2±5.8 % and 16.7±0.2 %, respectively. Chemotaxonomic data (sole isoprenoid quinone, MK-7; major cell-wall type, meso-diaminopimelic acid; major cellular fatty acids, anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0; major polar lipids, phosphatidylglycerol and diphosphatidylglycerol; DNA G+C content, 46.3 mol%) also supported the affiliation of strain MJ3T with the genus

Salimicrobium

. Therefore, strain MJ3T represents a novel species of the genus

Salimicrobium

, for which the name Salimicrobium
jeotgali sp. nov. is proposed. The type strain is MJ3T ( = KACC 16972T = JCM 19758T).
BIM and systemic ICT innovation in AEC
Authors: Singh Vishal
Published: July 2014

Purpose

– This paper aims to present a behavioural perspective on systemic innovation adoption decisions and resulting patterns in architecture engineering and construction (AEC). Building on the premise that innovation is always coupled with need identification or need creation, the paper analyses the systemic innovation-related needs and decisions of AEC actors.

Design/methodology/approach

– This research uses grounded theory to collect data through interviews, focus groups and field observation in Australian AEC. Based on the findings, three types of systemic innovation-related needs are identified to describe the dependencies in innovation-related needs of various actors in the construction innovation network, namely, need for the innovation, need to innovate and the need for the diffusion of innovation.

Findings

– It is found that the systemic innovation-related needs of actors in AEC network are interrelated. However, the systemic innovation-related decisions and, hence, the diffusion patterns are mediated by the degrees of freedom of the actors. Accordingly, it is argued that higher degrees of freedom of followers or the majority actors in AEC (to leave the innovation network) partially explain the slower rate of systemic innovation diffusion in AEC. Findings have implications on how systemic innovations in construction should be analysed and managed at the ecosystem level through an improved understanding of the interdependent innovation-related needs of the stakeholders.

Originality/value

– Innovation-related needs’ perspective provides novel and fresh insights into systemic innovation diffusion patterns in AEC and emphasises the significance of an ecosystem viewpoint to assess the roles of the different actors in AEC innovation network. The role of the degrees of freedoms of AEC actors in mediating systemic innovation diffusion is established.
A grey STA-GERT quality evaluation model for complex products based on manufacture-service dual-network
Authors: Xu Ruiting , Fang Zhigeng , Sun Jinyu
Published: July 2014

Purpose

– The purpose of this paper is to find out a scientific method to evaluate quality of complex products, whose quality is different from general products.

Design/methodology/approach

– Based on interval grey number theory, reliability analysis method and stochastic network theory, authors have established grey success tree analysis-graph evaluation and review technique (GSTA-GERT) model in this paper.

Findings

– Comparing complex products and general products, authors have found that complex products have two characters, i.e. quality of manufacture and quality of service. Furthermore, this paper has proved the GSTA-GERT model is a scientific and reasonable approach to estimate quality of complex products from the sight of manufacture-service network.

Originality/value

– This paper has established GSTA-GERT model, which surmounts the defect of traditional estimation method, such as lacking logic analysis in the method of analytic hierarchy process.
Grey power models based on optimization of initial condition and model parameters
Authors: Jong Yunchol , Liu Sifeng
Published: July 2014

Purpose

– The purpose of this paper is to propose a novel approach to improve prediction accuracy of grey power models including GM(1, 1) and grey Verhulst model.

Design/methodology/approach

– The modified new models are proposed by optimizing the initial condition and model parameters. The new initial condition consists of the first item and the last item of a sequence generated by applying the first-order accumulative generation operator on the sequence of raw data.

Findings

– It is shown that the newly modified grey power model is an extension of the previous optimized GM(1, 1) and grey Verhulst model. And the optimized initial condition reflected the principle of new information priority.

Practical implications

– The result of a numerical example indicates that the modified grey model presented in this paper with better prediction performance.

Originality/value

– The new initial condition are derived by weighted combination of the first item and the last item. The coefficients of weight obtained by the least square method.
Multi-terms MADM procedures with GRA and TOPSIS based on IFS and IVIFS
Authors: Bali Ozkan , Gumus Serkan
Published: July 2014

Purpose

– In the literature, many multi attributes decision making (MADM) models allow evaluation of the alternatives considering their current or last performance. However, in some MADM problems, not only current performance of alternatives but also their past performance should be taken into account in order to select the most appropriate alternative. For this reason, the purpose of this paper is to develop four procedures to evaluate the alternatives in MADM problems with multi terms.

Design/methodology/approach

– This study uses dynamic operators to aggregate the evaluation in different terms and then, grey relational analysis (GRA) and technique for order preference by similarity to ideal solution (TOPSIS) methods are utilized to determine the most appropriate alternative. Thus, four procedures which consist of these operators and methods are developed to evaluate the alternatives in multi terms.

Findings

– Some numerical examples are presented for the proposed procedures in multi-terms. Moreover, these four procedures are compared with other four procedures. The analyses of the results show that dynamic aggregation operators based on intuitionistic fuzzy set (IFS) and interval valued intuitionistic fuzzy sets (IVIFS) with GRA and TOPSIS can be used jointly for MADM problems in which alternatives are evaluated for different terms.

Originality/value

– One of the significant mistakes faced in some MADM problems is to take into account the current performance of alternatives or is to ignore their past performance. The right selection depends on past and current performance of the alternatives. The novelty of this study is to propose four procedures for solving MADM problems in multi terms based on IFS and IVIFS using dynamic aggregation operators and GRA and TOPSIS methods.
Who suffers pluralistic ignorance of conflict avoidance among Japanese?
Authors: Saito Takashi , Ohbuchi Ken-ichi
Published: July 2014

Purpose

– The purpose of this paper was to examine individual differences in the susceptibility to pluralistic ignorance of avoidance among Japanese by measuring the value of social harmony. It was hypothesized that the pluralistic ignorance of avoidance will occur more frequently among those with a low regard for the value of social harmony than those with a high regard.

Design/methodology/approach

– In two scenario studies, the authors had participants rate both their own avoidance and others’ avoidance in conflict situations. In Study 1, the authors measured the value of social harmony by Yamaguch et al.’s (1995) Collectivism Scale, and they originally constructed a scale to measure the value in Study 2.

Findings

– Consistent with the hypothesis, pluralistic ignorance occurred only among Japanese participants with a low regard for the value of social harmony and not among those who valued it highly.

Originality/value

– These findings suggest that those who have a different stance from the cultural value feel a normative pressure by the biased perception of others’ behavior due to pluralistic ignorance, which, as a result, works to preserve the predominant cultural value.
Ergonomic design of a wrist robot
Authors: Esmaeili Mohammad , Jarrassé Nathanaël , Dailey Wayne , Burdet Etienne , Campolo Domenico
Published: July 2014

Purpose

– The purpose of this paper is to propose a method to avoid hyperstaticity and eventually reduce the magnitude of undesired force/torques. The authors also study the influence of hyperstaticity on human motor control during a redundant task.

Design/methodology/approach

– Increasing the level of transparency of robotic interfaces is critical to haptic investigations and applications. This issue is particularly important to robotic structures that mimic the human counterpart's morphology and attach directly to the limb. Problems arise for complex joints such as the wrist, which cannot be accurately matched with a traditional mechanical joint. In such cases, mechanical differences between human and robotic joint cause hyperstaticity (i.e. over-constrained) which, coupled with kinematic misalignment, leads to uncontrolled force/torque at the joint. This paper focusses on the prono-supination (PS) degree of freedom of the forearm. The overall force and torque in the wrist PS rotation is quantified by means of a wrist robot.

Findings

– A practical solution to avoid hyperstaticity and reduce the level of undesired force/torque in the wrist is presented. This technique is shown to reduce 75 percent of the force and 68 percent of the torque. It is also shown an over-constrained mechanism could alter human motor strategies.

Practical implications

– The presented solution could be taken into account in the early phase of design of robots. It could also be applied to modify the fixation points of commercial robots in order to reduce the magnitude of reaction forces and avoid changes in motor strategy during the robotic therapy.

Originality/value

– In this paper for the first time the authors study the effect of hyperstaticity on both reaction forces and human motor strategies.
AGE-ility challenges, and management agendas for the organisation
Authors: C.J.M. Millar Carla , Culpin Vicki
Published: July 2014

Purpose

– The purpose of this paper is to provide an update of the Special Issue's field of research, give the structure of the Special Issue and introduce the papers in the collection, including management issues.

Design/methodology/approach

– A review of the Call for Papers and further research and a presentation of papers in the Special Issue paying attention to original contribution, research and management recommendations.

Findings

– This Special Issue is making a solid contribution to the field in not only addressing ageing and the ageing generation, but focusing strongly on the way both the ageing generation and other generations such as Gen Y and Gen X affect organisational dynamics, structure and career management.

Originality/value

– Original research brought together in a multi-faceted way outlining the challenges as well as management agendas for the organisation.
Causing something to be one way rather than another
Authors: Osimani Barbara
Published: July 2014

Purpose

– The purpose of this paper is to suggest a definition of genetic information by taking into account the debate surrounding it. Particularly, the objections raised by Developmental Systems Theory (Griffiths, 2001; Oyama 1985; Griffiths and Knight 1998) to Teleosemantic endorsements of the notion of genetic information (Sterelnyet al.1996; Maynard Smith, 2000; Jablonka, 2002) as well as deflationist approaches which suggest to ascribe the notion of genetic information a heuristic value at most, and to reduce it to that of causality (Godfrey-Smith, 2000; Boniolo, 2003, 2008).

Design/methodology/approach

– The paper presents the notion of genetic information through its historical evolution and analyses it with the conceptual tools offered by philosophical theories of causation on one side (“causation as influence,” Woodward, 2010; Waters, 2007; Lewis, 2000) and linguistics on the other (“double articulation” Martinet, 1960).

Findings

– The concept of genetic information is defined as a special kind of cause which causes something to be one way rather than another, by combining elementary units one way rather than another. Tested against the notion of “genetic error” this definition demonstrates to provide an exhaustive account of the common denominators associated with the notion of genetic information: causal specificity; combinatorial mechanism; arbitrariness.

Originality/value

– The definition clarifies how the notion of information is understood when applied to genetic phenomena and also contributes to the debate on the notion of information, broadly meant, which is still affected by lack of consensus (Floridi, 2013).