bluuebunny/crossref_metadata_2025 huggingface dataset:
A parallelizable block cellular automaton for the study of diffusion of binary mixtures containing CO2 in microporous materials
Authors: Pintus Alberto M. , Pazzona Federico G. , Demontis Pierfranco , Suffritti Giuseppe B.
Published: October 2011

We applied a method based on a block cellular automaton (BCA) algorithm to the study of diffusion of various binary mixtures adsorbed in a model microporous material, such as zeolite ZK4. Our aim was to test the capability of our model to cope with systems in which more than one species is present, using a set of parameters based on heuristic considerations from the molecular dynamics (MD) results present in the literature. A rigorous methodology for the assignment of suitable adsorption energies and diffusion activation barriers for our BCA has not been developed yet, nonetheless the results were quite interesting at this stage and we obtained a good qualitative agreement with MD data in the literature. The mixtures we investigated contain CO2, which causes the so-called segregation-effect, a strong suppression of self-diffusivity of co-adsorbed species. This effect gives rise to relevant problems in the application of some well established and robust methods, while our model proved to be able to reproduce both the common features and the segregation anomaly in the trends of diffusion.
Characteristic impedance and capacitance analysis of Blumlein type pulse forming line of accelerator based on tape helix
Authors: Zhang Yu , Liu Jinliang , Fan Xuliang , Zhang Hongbo , Wang Shiwen , Feng Jiahuai
Published: October 2011

In this paper, the electromagnetic dispersion theory and the classic telegraph equations were combined to calculate the important parameters of the helical Blumlein pulse forming line (BPFL) of accelerator based on tape helix. In the work band of the BPFL at several hundred ns range, electromagnetic dispersion characteristics were almost determined by the zeroth harmonic. In order to testify the dispersion theory of BPFL in this paper, filling dielectrics, such as de-ionized water, transformer oil, and air were employed in the helical BPFL, respectively. Parameters such as capacitance, inductance, characteristic impedance, and pulse duration of the BPFL were calculated. Effects of dispersion on these parameters were analyzed. Circuit simulation and electromagnetic simulation were carried out to prove these parameters of BPFL filled with these three kinds of dielectrics, respectively. The accelerator system was set up, and experimental results also corresponded to the theoretical calculations. The average theoretical errors of impedances and pulse durations were 3.5% and 3.4%, respectively, which proved the electromagnetic dispersion analyses in this paper.
Kolmogorov similarity scaling for one-particle Lagrangian statistics
Authors: Sawford Brian L. , Yeung P. K.
Published: October 2011

We use direct numerical simulation data up to a Taylor scale Reynolds number Rλ = 1000 to investigate Kolmogorov similarity scaling in the inertial sub-range for one-particle Lagrangian statistics. Although similarity scaling is not achieved at these Reynolds numbers for the Lagrangian velocity structure function, we show clearly that it is achieved for the Lagrangian acceleration frequency spectrum and the scaling range becomes wider with increasing Reynolds number. Stochastic and heuristic model calculations suggest that the difference in behavior observed for the structure function and spectrum is simply a consequence of different rates of convergence to scaling behavior with increasing Reynolds number. Our estimate C0 ≈ 6.9 ± 0.2 for the Lagrangian structure function constant is close to earlier estimates based on extrapolation of the peak value of the compensated structure function. The results presented here suggest prospects for studying Kolmogorov similarity for Lagrangian statistics using the latest innovations in simulation, and measurement techniques are more hopeful than previously suggested in the literature.
Modelling of HNO3-mediated laser-induced condensation: A parametric study
Authors: Rohwetter P. , Kasparian J. , Wöste L. , Wolf J.-P.
Published: October 2011

Based on both static (extended Köhler) and dynamic modelling, we investigate the influence of temperature, humidity, HNO3 initial concentration, as well as of the particle concentration, on the efficiency of HNO3-mediated laser-induced condensation. This mechanism is most efficient for low temperatures, high HNO3 concentration, and relative humidities. It is, however, still active up to 30 °C, down to 70% relative humidity, and below the ppm level of HNO3. Furthermore, lower particle concentration minimizing the depletion of both HNO3 and water vapor is more favourable to particle growth.
An efficient linear scaling procedure for constructing localized orbitals of large molecules based on the one-particle density matrix
Authors: Guo Yang , Li Wei , Li Shuhua
Published: October 2011

We have developed a linear-scaling algorithm for obtaining the Boys localized molecular orbitals from the one-particle density matrix. The algorithm is made up of two steps: the Cholesky decomposition of the density matrix to obtain Cholesky molecular orbitals and the subsequent Boys localization process. Linear-scaling algorithms have been proposed to achieve linear-scaling calculations of these two steps, based on the sparse matrix technique and the locality of the Cholesky molecular orbitals. The present algorithm has been applied to compute the Boys localized orbitals in a number of systems including α-helix peptides, water clusters, and protein molecules. Illustrative calculations demonstrate that the computational time of obtaining Boys localized orbitals with the present algorithm is asymptotically linear with increasing the system size.
Size-extensive vibrational self-consistent field method
Authors: Keçeli Murat , Hirata So
Published: October 2011

The vibrational self-consistent field (VSCF) method is a mean-field approach to solve the vibrational Schrödinger equation and serves as a basis of vibrational perturbation and coupled-cluster methods. Together they account for anharmonic effects on vibrational transition frequencies and vibrationally averaged properties. This article reports the definition, programmable equations, and corresponding initial implementation of a diagrammatically size-extensive modification of VSCF, from which numerous terms with nonphysical size dependence in the original VSCF equations have been eliminated. When combined with a quartic force field (QFF), this compact and strictly size-extensive VSCF (XVSCF) method requires only quartic force constants of the \documentclass[12pt]{minimal}\begin{document}$\partial ^4 V / \partial Q_i^2 \partial Q_j^2$\end{document}∂4V/∂Qi2∂Qj2 type, where V is the electronic energy and Qi is the ith normal coordinate. Consequently, the cost of a XVSCF calculation with a QFF increases only quadratically with the number of modes, while that of a VSCF calculation grows quartically. The effective (mean-field) potential of XVSCF felt by each mode is shown to be harmonic, making the XVSCF equations subject to a self-consistent analytical solution without matrix diagonalization or a basis-set expansion, which are necessary in VSCF. Even when the same set of force constants is used, XVSCF is nearly three orders of magnitude faster than VSCF implemented similarly. Yet, the results of XVSCF and VSCF are shown to approach each other as the molecular size is increased, implicating the inclusion of unnecessary, nonphysical terms in VSCF. The diagrams of the XVSCF energy expression and their evaluation rules are also proposed, underscoring their connected structures.
Origin of the electrical instabilities in GaN/AlGaN double-barrier structure
Authors: Sakr S. , Warde E. , Tchernycheva M. , Rigutti L. , Isac N. , Julien F. H.
Published: October 2011

The effect of the temperature on the electrical characteristics in GaN-based resonant tunneling diodes is studied both theoretically and experimentally. At room temperature, the current-voltage measurements show reproducible negative differential resistances and a current hysteresis. However these features disappear when the temperature is decreased down to 100 K. In addition, the current exhibits transients over a few tenths of seconds which effect disappears at low temperatures. Based on these results, we conclude that the observed negative differential resistance at room temperature is not due to electron resonant tunneling but to trap charging and release.
Ultrafast polariton population build-up mediated by molecular phonons in organic microcavities
Authors: Somaschi N. , Mouchliadis L. , Coles D. , Perakis I. E. , Lidzey D. G. , Lagoudakis P. G. , Savvidis P. G.
Published: October 2011

A key prerequisite for low-threshold polariton lasing in organic or inorganic microcavity systems is the efficient population of the lower polariton ground state. Here, we report the observation of a resonant phonon-mediated relaxation process which gives rise to nonthermal polariton population with sub 100 fs build-up times. This mechanism is manifested by discrete maxima of the angular-resolved photoluminescence intensity, with corresponding shortening of the photoluminescence rise time at respective phonon resonances. The realization of enhanced relaxation rates in disordered J-aggregate systems is important for developing room temperature organic laser sources with less fabrication complexity than their crystalline counterparts.
Molecular orbital ordering in titania and the associated semiconducting behavior
Authors: Park Joseph , Ok Kyung-Chul , Du Ahn Byung , Hun Lee Je , Park Jae-Woo , Chung Kwun-Bum , Park Jin-Seong
Published: October 2011

RF-sputtered TiOx layers were thermally treated and the associated thin-film transistor properties were studied. X-ray diffraction and x-ray absorption spectroscopy analyses indicate that as-grown amorphous TiOx films crystallize to anatase at temperatures above 450 °C in air. Thin-film transistors incorporating anatase active layers exhibit n-type behavior, with field effect mobility values near 0.11 cm2/Vs when annealed at 550 °C. Such a phenomenon is suggested to originate from the ordering of Ti 3d orbitals upon crystallization, and the mobility enhancement at higher annealing temperatures may be attributed to the reduced grain boundary scattering of carriers by virtue of enlarged average grain size.
InAs quantum dots and quantum wells grown on stacking-fault controlled InP nanowires with wurtzite crystal structure
Authors: Kawaguchi Kenichi , Heurlin Magnus , Lindgren David , Borgström Magnus T. , Ek Martin , Samuelson Lars
Published: October 2011

Heteroepitaxial growth of InAs was investigated on sidewalls of InP nanowires (NWs) using metal-organic vapor phase epitaxy. InAs quantum wells (QWs) with smooth surface were formed on the InP NWs having perfect wurtzite phase structure. On the other hand, InAs quantum dots (QDs) were formed on wurtzite InP NWs purposely introduced with stacking-fault segments. Photoluminescence from single NWs attributed to both QWs and QDs was observed.
Multijoule scaling of laser-induced condensation in air
Authors: Petrarca M. , Henin S. , Stelmaszczyk K. , Bock S. , Kraft S. , Schramm U. , Vaneph C. , Vogel A. , Kasparian J. , Sauerbrey R. , Weber K. , Wöste L. , Wolf J.-P.
Published: October 2011

Using 100 TW laser pulses, we demonstrate that laser-induced nanometric particle generation in air increases much faster than the beam-averaged incident intensity. This increase is due to a contribution from the photon bath, which adds up with the previously identified one from the filaments and becomes dominant above 550 GW/cm2. It appears related to ozone formation via multiphoton dissociation of the oxygen molecules and demonstrates the critical need for further increasing the laser energy in view of macroscopic effects in laser-induced condensation.
Three-dimensional cellular focusing utilizing a combination of insulator-based and metallic dielectrophoresis
Authors: Huang Ching-Te , Weng Cheng-Hsin , Jen Chun-Ping
Published: October 2011

Particle focusing in microfluidic devices is a necessary step in medical applications, such as detection, sorting, counting, and flow cytometry. This study proposes a microdevice that combines insulator-based and metal-electrode dielectrophoresis for the three-dimensional focusing of biological cells. Four insulating structures, which form an X pattern, are employed to confine the electric field in a conducting solution, thereby creating localized field minima in the microchannel. These electrodes, 56-μm-wide at the top and bottom surfaces, are connected to one electric pole of the power source. The electrodes connected to the opposite pole, which are at the sides of the microchannel, have one of three patterns: planar, dual-planar, or three-dimensional. Therefore, low-electric-field regions at the center of the microchannel are generated to restrain the viable HeLa cells with negative dielectrophoretic response. The array of insulating structures aforementioned is used to enhance the performance of confinement. According to numerical simulations, three-dimensional electrodes exhibit the best focusing performance, followed by dual-planar and planar electrodes. Experimental results reveal that increasing the strength of the applied electric field or decreasing the inlet flow rate significantly enhances focusing performance. The smallest width of focusing is 17 μm for an applied voltage and an inlet flow rate of 35 V and 0.5 μl/min, respectively. The effect of the inlet flow rate on focusing is insignificant for an applied voltage of 35 V. The proposed design retains the advantages of insulator-based dielectrophoresis with a relatively low required voltage. Additionally, complicated flow controls are unnecessary for the three-dimensional focusing of cells.
Characterization of organic materials by LIBS for exploration of correlation between molecular and elemental LIBS signals
Authors: Rai Shikha , Rai Awadhesh Kumar
Published: October 2011

The present study is performed for the preparation of a database by accumulating LIBS spectra of 4-nitroaniline and 4-nitrotoluene in air and argon. Changes in the behavior of the molecular bands of the C2 Swan system and CN violet system as well as of atomic lines of C, H and N in the LIBS signal are appreciable in argon. In order to explore the correlation between observed LIBS signal and molecular composition of these materials, normalized intensities of the emission lines have been estimated for each compound. It has been found that the relative rates of increase/decrease in the normalized intensities for all sets are higher for 4-nitrotoluene in argon. The cause of the higher rate for 4-nitrotoluene might be due to the possession of a distinctive functional group. The ultimate goal behind the whole study is to use this data-base as input for the discrimination of energetic materials.
Thin-film superconducting resonator tunable to the ground-state hyperfine splitting of 87Rb
Authors: Kim Z. , Vlahacos C. P. , Hoffman J. E. , Grover J. A. , Voigt K. D. , Cooper B. K. , Ballard C. J. , Palmer B. S. , Hafezi M. , Taylor J. M. , Anderson J. R. , Dragt A. J. , Lobb C. J. , Orozco L. A. , Rolston S. L. , Wellstood F. C.
Published: October 2011

We describe a thin-film superconducting Nb microwave resonator, tunable to within 0.3 ppm of the hyperfine splitting of 87Rb at fRb = 6.834683 GHz. We coarsely tuned the resonator using electron-beam lithography, decreasing the resonance frequency from 6.8637 GHz to 6.8278 GHz. For in situ fine tuning at 15 mK, the resonator inductance was varied using a piezoelectric stage to move a superconducting pin above the resonator. We found a maximum frequency shift of about 8.7 kHz per 60-nm piezoelectric step and a tuning range of 18 MHz.
Science controversies past and present
Authors: Sherwood Steven
Published: October 2011

Reactions to the science of global warming have followed a similar course to those of other inconvenient truths from physics.
Values, Meanings, and Positionalities: The Controversial Valuation of Water in Rio de Janeiro
Authors: Ioris Antonio A R
Published: October 2011

Water is not only a valuable substance, but is also valued in different ways dependent on substantive social, ecological, and historical conditions. The concept of water value positionality is introduced to describe the dynamic ensemble of meanings forged from cooperation and competition in the allocation, use, and conservation of water. Positionality helps us to understand water conflicts as individuals and groups struggling to legitimise their valuation of water. The explanatory function of positionality is demonstrated with an empirical case study in the metropolitan region of Rio de Janeiro. Hegemonic positionality depicts water as an economic resource required for regional development and urban growth. This has been increasingly challenged by sectors of the state apparatus who call for the monetary valuation of water. Beyond these two perspectives, there exists a vast range of water values articulated by the local communities in their struggle for survival and political affirmation. The conclusion is that, in the process of constantly revaluing water, there are temporary ‘positions of value’ that last and change with sociocultural and politicoecological experiences.
Hearing but Not Listening? A Participatory Assessment of Public Participation in Planning
Authors: Conrad Elisabeth , Cassar Louis F , Christie Mike , Fazey Ioan
Published: October 2011

Whilst public participation is now accepted as an essential requirement of planning, there is limited literature which considers the effectiveness of participation in practice. In this study we focus on the perspectives of members of the public, and planners and policy makers in the island state of Malta, to identify (i) expectations of the participation process, (ii) the extent to which practices meet expectations, and (iii) ways in which participation practices could be rendered more effective. Five key areas of concern emerge: (a) lack of influence on decisions, (b) lack of professional ethics and expertise, (c) methods and techniques used, (d) the nature of information provision, and (e) local cultural influences. Results illustrate the inadequacy of present legal requirements for ensuring effective participation, and a related need for institutionalizing review mechanisms. Results also reveal tension between positivist views of planning as an expert discipline, and public expectations of democracy. Furthermore, the study provides wider insights into processes of assessment and evaluation.
The Effect of Circumstellar Material on the Light Curves of Eclipsing Binary Systems
Authors: Ghoreyshi S. M. R. , Ghanbari J. , Salehi F.
Published: October 2011

This study inspects the influence of various effects and free parameters of the accretion disc and circumstellar material on the emerging light curve of eclipsing binary systems that have a circumstellar disc, by using the SHELLSPEC code. The results indicate that some of the parameters, namely the temperature and inclination of the disc, spot, jet, stream and shell, significantly affect on the emerging light curve, while some other parameters, namely the exponent of the power-law behavior of the density of the disc, microturbulence, inner and outer radius of the disc, do not noticeably affect on the emerging light curve. An application to the Algol-type eclipsing binary system AV Del and an accretion disc model for the system using the SHELLSPEC code is included.
The use of chitosan in antimicrobial films for food protection.
Authors: Fernandez-Saiz P. , Ocio M. J. , Lagaron J. M.
Published: October 2011

Despite the large number of publications related to chitosan and its derivates, there is still a great controversy regarding the phenomenology and mechanisms of the biocide properties of this natural component. This review aims at highlighting the antimicrobial activity of chitosan for its optimal application as an active packaging material to maintain the microbial safety of a food product. For this purpose, the mechanisms involved and the factors affecting the biocide properties of chitosan and chitosan-based films are summarized. Also, the behaviour of chitosan when incorporated in a more water-resistant polymer matrix or when evaluated on a real food system is outlined. A clear understanding of all these features constitutes a previous crucial step for an optimum design of active antimicrobial food packaging structures based on the use of this biopolymer as an internal coating of the packaging material or as a food coating in itself for moistured foods.
Natural antimicrobials for food processing.
Authors: Ramos-Villarroel A. Y. , Soliva-Fortuny R. , Martín-Belloso O.
Published: October 2011

Natural antimicrobial agents are required to ensure that manufactured foods remain safe and unspoiled. This paper will focus on the definition, types, mechanisms of action and factors that affect the activity and application potential of food-natural antimicrobials for food processing. Naturally occurring antimicrobial compounds derived from animal, plant and microbial sources have potential for use alone, as adjuncts to traditional, regulatory-approved antimicrobial preservatives, or in combination with other food preservation processes. Among the many natural antimicrobials discussed in this paper, only a few have been tested or applied to foods. Some examples include the antibiotic natamycin, the bacteriocin nisin, lactoferrin, hydrogen peroxide, polysaccharides as chitosan and enzymes as egg-white lysozyme. This review will focus on the effects and efficacy of the different compounds in real foods and food-system models, the mechanisms of action against micro-organisms, the interactions with food components and other preservative systems, as well as their influence on food quality, toxicology and safety.
Pricing Risk and Ambiguity: The Effect of Perspective Taking
Authors: Trautmann Stefan T. , Schmidt Ulrich
Published: October 2011

In the valuation of uncertain prospects, a difference is often observed between selling and buying perspectives. This paper distinguishes between risk (known probabilities) and ambiguity (unknown probabilities) in decisions under uncertainty and shows that the valuation disparity increases under ambiguity compared to risk. It is found that both the comparative versus noncomparative evaluation of risky and ambiguous prospects and the uniqueness of the valuation perspective (either seller or buyer) moderate this increase in the disparity under ambiguity. The finding is consistent with recent theoretical accounts of pricing under uncertainty. We discuss implications for market behaviour and for the ambiguity paradigm as a research tool.
Reassessing Water Security in the Mekong: The Chinese Rapprochement with Southeast Asia
Authors: Onishi Kayo
Published: October 2011

This paper focuses on China's incentive in basin-wide cooperation in the Mekong Basin and argues that understanding the role of three factors—the non-water resources, geography, and climate regimes—is critical to explaining China's cooperative attitude. More specifically, it addresses the overarching question: Under what conditions are the Mekong riparian states able to govern the shared water cooperatively to overcome collective action problems in situations, where the presence of the hegemonic upstream state like China precludes cooperation? The core of the paper offers an integrative approach that connects water resources, non-water resources, geography, and climate types for explaining international riparian politics.
TPX2 regulates the localization and activity of Eg5 in the mammalian mitotic spindle
Authors: Ma Nan , Titus Janel , Gable Alyssa , Ross Jennifer L. , Wadsworth Patricia
Published: October 2011

Mitotic spindle assembly requires the regulated activity of numerous spindle-associated proteins. In mammalian cells, the Kinesin-5 motor Eg5 interacts with the spindle assembly factor TPX2, but how this interaction contributes to spindle formation and function is not established. Using bacterial artificial chromosome technology, we generated cells expressing TPX2 lacking the Eg5 interaction domain. Spindles in these cells were highly disorganized with multiple spindle poles. The TPX2–Eg5 interaction was required for kinetochore fiber formation and contributed to Eg5 localization to spindle microtubules but not spindle poles. Microinjection of the Eg5-binding domain of TPX2 resulted in spindle elongation, indicating that the interaction of Eg5 with TPX2 reduces motor activity. Consistent with this possibility, we found that TPX2 reduced the velocity of Eg5-dependent microtubule gliding, inhibited microtubule sliding, and resulted in the accumulation of motor on microtubules. These results establish a novel function of TPX2 in regulating the location and activity of the mitotic motor Eg5.
Entire functions of finite order as solutions to certain complex linear differential equations
Authors: Anghel N.
Published: October 2011

When is an entire function of finite order a solution to a complex 2nd order homogeneous linear differential equation with polynomial coefficients? In this paper we will give two (equivalent) answers to this question. The starting point of both answers is the Hadamard product representation of a given entire function of finite order. While the first answer involves certain Stieltjes-like relations associated to the function, the second one requires the vanishing of all but finitely many suitable expressions constructed via the Gil’ sums of the zeros of the function. Applications of these results will also be given, most notably to the spectral theory of one-dimensional Schrödinger operators with polynomial potentials.
On Gorenstein injectivity of top local cohomology modules
Authors: Yoshizawa Takeshi
Published: October 2011

R. Sazeedeh showed that top local cohomology modules are Gorenstein injective in a Gorenstein local ring with at most two dimensions. In this paper, it is proved that the condition of dimension in his result cannot be relaxed and the conclusion in his result holds for complete local hypersurface rings with any dimension.
Fate of three Australian teleosts after ingesting conventional and modified stainless- and carbon-steel hooks
Authors: McGrath Shane P. , Broadhurst Matt K. , Butcher Paul A. , Cairns Stuart C.
Published: October 2011

McGrath, S. P., Broadhurst, M. K., Butcher, P. A., and Cairns, S. C. 2011. Fate of three Australian teleosts after ingesting conventional and modified stainless- and carbon-steel hooks. – ICES Journal of Marine Science, 68: 2114–2122. In response to concerns over the fate of three Australian teleosts (mulloway, Argyrosomus japonicus, yellowfin bream, Acanthopagrus australis, and snapper, Pagrus auratus) released with ingested recreational hooks, experiments were carried out to determine whether ejection could be promoted via different wire materials and/or their modification. Between 108 and 114 fish of each species were angled and allowed to ingest conventional or modified (with notches to reduce wire diameter by ∼20%) J-hooks (∼250 mm2) made from three materials (stainless steel and nickel-plated and red-lacquer carbon steel), before being released into tanks and monitored with control fish for up to 61 d. Total mortalities were 35, 24, and 25% for mulloway (over 61 d), yellowfin bream (over 35 d), and snapper (over 41 d), respectively. Of the survivors, 30, 61, and 77%, respectively, ejected their hooks (and only one hook-ejected fish died). For yellowfin bream, hook ejection (and hence survival) was positively correlated with total length, and hook oxidation was the key predictor of ejection from mulloway and snapper, which could be promoted by selecting carbon-steel designs with narrow wire diameters and minimal protective coating. The choice of coating might also be important, with relatively greater mortality among mulloway and yellowfin bream that ingested nickel-plated hooks.
The sense of touch in the star-nosed mole: from mechanoreceptors to the brain
Authors: Catania Kenneth C.
Published: October 2011

Star-nosed moles are somatosensory specialists that explore their environment with 22 appendages that ring their nostrils. The appendages are covered with sensory domes called Eimer's organs. Each organ is associated with a Merkel cell–neurite complex, a lamellated corpuscle, and a series of 5–10 free nerve endings that form a circle of terminal swellings. Anatomy and electrophysiological recordings suggest that Eimer's organs detect small shapes and textures. There are parallels between the organization of the mole's somatosensory system and visual systems of other mammals. The centre of the star is a tactile fovea used for detailed exploration of objects and prey items. The tactile fovea is over-represented in the neocortex, and this is evident in the modular, anatomically visible representation of the star. Multiple maps of the star are visible in flattened cortical preparations processed for cytochrome oxidase or NADPH-diaphorase. Star-nosed moles are the fastest known foragers among mammals, able to identify and consume a small prey item in 120 ms. Together these behavioural and nervous system specializations have made star-nosed moles an intriguing model system for examining general and specialized aspects of mammalian touch.
Active touch in orthopteroid insects: behaviours, multisensory substrates and evolution
Authors: Comer Christopher , Baba Yoshichika
Published: October 2011

Orthopteroid insects (cockroaches, crickets, locusts and related species) allow examination of active sensory processing in a comparative framework. Some orthopteroids possess long, mobile antennae endowed with many chemo- and mechanoreceptors. When the antennae are touched, an animal's response depends upon the identity of the stimulus. For example, contact with a predator may lead to escape, but contact with a conspecific may usually not. Active touch of an approaching object influences the likelihood that a discrimination of identity will be made. Using cockroaches, we have identified specific descending mechanosensory interneurons that trigger antennal-mediated escape. Crucial sensory input to these cells comes from chordotonal organs within the antennal base. However, information from other receptors on the base or the long antennal flagellum allows active touch to modulate escape probability based on stimulus identity. This is conveyed, at least to some extent, by textural information. Guidance of the antennae in active exploration depends on visual information. Some of the visual interneurons and the motor neurons necessary for visuomotor control have been identified. Comparisons across Orthoptera suggest an evolutionary model where subtle changes in the architecture of interneurons, and of sensorimotor control loops, may explain differing levels of vision–touch interaction in the active guidance of behaviour.
Obtaining information by dynamic (effortful) touching
Authors: Turvey M. T. , Carello Claudia
Published: October 2011

Dynamic touching is effortful touching. It entails deformation of muscles and fascia and activation of the embedded mechanoreceptors, as when an object is supported and moved by the body. It is realized as exploratory activities that can vary widely in spatial and temporal extents (a momentary heft, an extended walk). Research has revealed the potential of dynamic touching for obtaining non-visual information about the body (e.g. limb orientation), attachments to the body (e.g. an object's height and width) and the relation of the body both to attachments (e.g. hand's location on a grasped object) and surrounding surfaces (e.g. places and their distances). Invariants over the exploratory activity (e.g. moments of a wielded object's mass distribution) seem to ground this ‘information about’. The conception of a haptic medium as a nested tensegrity structure has been proposed to express the obtained information realized by myofascia deformation, by its invariants and transformations. The tensegrity proposal rationalizes the relative indifference of dynamic touch to the site of mechanical contact (hand, foot, torso or probe) and the overtness of exploratory activity. It also provides a framework for dynamic touching's fractal nature, and the finding that its degree of fractality may matter to its accomplishments.
Light touch for balance: influence of a time-varying external driving signal
Authors: Wing Alan M. , Johannsen Leif , Endo Satoshi
Published: October 2011

Sensory information about body sway is used to drive corrective muscle action to keep the body's centre of mass located over the base of support provided by the feet. Loss of vision, by closing the eyes, usually results in increased sway as indexed by fluctuations (i.e. standard deviation, s.d.) in the velocity of a marker at C7 on the neck, s.d. dC7. Variability in the rate of change of centre of pressure (s.d. dCoP), which indexes corrective muscle action, also increases during upright standing with eyes closed. Light touch contact by the tip of one finger with an environmental surface can reduce s.d. dC7 and s.d. dCoP as effectively as opening the eyes. We review studies of light touch and balance and then describe a novel paradigm for studying the nature of somatosensory information contributing to effects of light touch balance. We show that ‘lighttighttouch’ contact by the index finger held in the thimble of a haptic device results in increased anteroposterior (AP) sway with entraining by either simple or complex AP sinusoidal oscillations of the haptic device. Moreover, sway is also increased when the haptic device plays back the pre-recorded AP sway path of another person. Cross-correlations between hand and C7 motion reveal a 176 ms lead for the hand and we conclude that light tight touch affords an efficient route for somatosensory feedback support for balance. Furthermore, we suggest that the paradigm has potential to contribute to the understanding of interpersonal postural coordination with light touch in future research.
Methanol–Acetone Fixation of Drosophila Testes
Authors: Bonaccorsi Silvia , Giansanti Maria G. , Cenci Giovanni , Gatti Maurizio
Published: October 2011

This protocol describes two techniques for methanol–acetone fixation of Drosophila melanogaster testis squashes. The first method results in very good preservation of cell morphology. Fixed cells viewed by phase-contrast optics show most of the structural details that can be seen in live material. This allows analysis of unstained fixed preparations and selection of the most suitable ones for immunostaining. Remarkably, the Y loops, which are usually faint and labile in living preparations, become clearly apparent after this type of fixation. Moreover, this fixation method results in excellent microtubule preservation for immunostaining with antitubulin antibodies. The main disadvantage of this technique is poor preservation of chromosome structure. In most instances, the chromosomes do not show a distinct morphology and tend to coalesce into one or more masses of chromatin. The second technique for methanol–acetone fixation described here has proved to be particularly suitable for γ-tubulin and centrosomin immunostaining. It results in preparations having the same characteristics as those obtained with the first method.
Time-Lapse Imaging of Live Phallusia Embryos for Creating 3D Digital Replicas: Movie 1.
Authors: Robin François B. , Dauga Delphine , Tassy Olivier , Sobral Daniel , Daian Fabrice , Lemaire Patrick
Published: October 2011

During embryonic development, cell behaviors that are tightly coordinated both spatially and temporally integrate at the tissue level and drive embryonic morphogenesis. Over the past 20 years, advances in imaging techniques, in particular, the development of confocal imaging, have opened a new world in biology, not only giving us access to a wealth of information, but also creating new challenges. It is sometimes difficult to make the best use of the recordings of the complex, inherently three-dimensional (3D) processes we now can observe. In particular, these data are often not directly suitable for even simple but conceptually fundamental quantifications. This article provides a method to fluorescently label and image structures of interest that will subsequently be reconstructed, such as cell membranes or nuclei. The protocol describes live imaging of Phallusia mammillata embryos, which are robust, colorless, and optically transparent with negligible autofluorescence. Their diameter ranges from 100 µm to 120 µm, which allows time-lapse microscopy of whole embryos using two-photon microscopy with a high-resolution objective. Although two-photon imaging is described in detail, any imaging technology that results in a z-stack may be used. The resulting image stacks can subsequently be digitalized and segmented to produce 3D embryo replicas that can be interfaced to a model organism database and used to quantify cell shapes.
The In Vivo Invasion Assay: Preparation and Handling of Collection Needles: Figure 1.
Authors: Wyckoff Jeffrey , Gligorijevic Bojana , Entenberg David , Segall Jeffrey , Condeelis John
Published: October 2011

Analysis of the individual steps in metastasis is crucial if insights at the molecular level are to be linked to the cell biology of cancer. A technical hurdle to achieving the analysis of the individual steps of metastasis is the fact that, at the gross level, tumors are heterogeneous in both animal models and patients. Human primary tumors show extensive variation in all properties ranging from growth and morphology of the tumor through tumor-cell density in the blood and formation and growth of metastases. Methods capable of the direct visualization and analysis of tumor-cell behavior at single-cell resolution in vivo have become crucial in advancing the understanding of mechanisms of metastasis, the definition of microenvironment, and the markers related to both. High-resolution multiphoton imaging of tumors in vivo is a valuable tool in this regard. Because tumor cells have been found to be attracted to blood vessels, the in vivo invasion assay was developed to analyze which factors may stimulate invasion of these cells into the vessels. This protocol describes the preparation and handling of collection needles for the assay. A set of 33-gauge needles is used to create artificial or surrogate blood vessels that are injected into tumors, using a special holding device attached to a micromanipulator to stabilize the needle positions during and after insertion into the anesthetized animal. The needles are filled with Matrigel and various growth factors to determine which of these factors may influence the invading tumor cells.
Basic Fluorescence Correlation Spectroscopy Setup and Measurement
Authors: Kinjo Masataka , Sakata Hiroshi , Mikuni Shintaro
Published: October 2011

Fluorescence correlation spectroscopy (FCS) has become a powerful and sensitive tool in biochemistry and biophysics. It directly obtains physical parameters such as the average number of fluorescent molecules and their diffusion time in a tiny detection area. It also provides other useful information such as the brightness of molecules. Ultimately, it can give precise information about molecular interactions in the aqueous condition. This protocol outlines the basic FCS setup and how measurements are made.
Special directions in momentum space. I. Cubic symmetries
Authors: Kontrym-Sznajd G. , Samsel-Czekała M.
Published: October 2011

Some new sets of special directions (SDs) in the Brillouin zone for cubic structures are presented. They allow for construction in the reciprocal space of anisotropic quantities, having Γ1symmetry, from knowledge of such quantities along a limited number of SDs. These SDs also define which spectra, measured, for example, in Compton scattering experiments, are the most efficient for reconstructing three-dimensional densities from their one-dimensional projections. The new SDs are compared with results obtained by other authors.
Titanium local structure in tektite probed by X-ray absorption fine structure spectroscopy
Authors: Wang Ling , Yoshiasa Akira , Okube Maki , Takeda Takashi
Published: October 2011

The local structure of titanium in tektites from six strewn fields was studied by TiK-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) in order to provide quantitative data on Ti—O distance and Ti coordination number. The titanium in tektites possessed different coordination environment types. XANES spectra patterns revealed resemblance to high-temperature TiO2–SiO2glass and TiO2anatase. All samples showed that the valence of Ti is 4+. Based on the Ti—O distances, coordination numbers and radial distribution function determined by EXAFS analyses, the tektites were classified into three types: type I, Ti occupies a four-coordinated tetrahedral site with Ti—O distances of 1.84–1.79 Å; type II, Ti occupies a five-coordinated trigonal bipyramidal or tetragonal pyramidal site with Ti—O distances of 1.92–1.89 Å; type III, Ti occupies a six-coordinated octahedral site with Ti—O distances of 2.00–1.96 Å. Although Ti occupies the TiO6octahedral site in most titanium minerals under ambient conditions, some tektites have four- and five-coordinated Ti. This study indicated that the local structure of Ti might change in impact events and the following stages.
Aliskiren reduces portal pressure in portal hypertensive rats
Authors: Chang Ching‐Chih , Lee Wen‐Shin , Huang Hui‐Chun , Lee Fa‐Yauh , Wang Sun‐Sang , Lin Han‐Chieh , Nong Jing‐Yi , Lee Shou‐Dong
Published: October 2011

Eur J Clin Invest 2012; 42 (5): 526–533

Background  Aliskiren is a direct renin inhibitor used in the treatment for arterial hypertension. It can also augment nitric oxide (NO) production, which plays a crucial role in the pathogenesis of portal hypertension and modulation of porto‐systemic collaterals. This study investigated the effects of aliskiren on portal pressure and porto‐systemic collaterals of portal vein‐ligated (PVL) rats.

Materials and methods  Sham‐operated and PVL rats received aliskiren (50 mg/kg per day) or distilled water (control) treatment for 10 days. The mean arterial pressure and portal pressure were measured by catheterization of the right femoral artery and mesenteric vein, while the superior mesenteric arterial blood flow was measured by Doppler technique. The left adrenal vein and superior mesentery artery were dissected for mRNA study. The PVL rats also underwent preincubation with (i) Krebs solution (control); (ii) 10−4 M aliskiren; or (iii) 10−4 M aliskiren plus nonselective NO inhibitor Nω‐nitro‐l‐arginine (10−4 M), followed by the addition of arginine vasopressin (AVP) to evaluate the collateral vascular responsiveness.

Results  Aliskiren had systemic arterial pressure‐ and portal pressure‐lowering effects in PVL rats. Superior mesentery arterial resistance also decreased. The constitutive NO synthase was enhanced in the left adrenal vein and superior mesentery artery after aliskiren treatment. Aliskiren attenuated the collateral vasoconstrictive effects of AVP, but the vasodilatory effects were abolished after nonselective NO synthase inhibition.

Conclusions  Chronic aliskiren use reduces portal pressure in portal hypertensive rats partly due to the modulation of splanchnic and collateral NO synthase.
On the frontlines of the law: Legal advocacy and political protest by lawyers in contested Kashmir (Respond to this article at http://www.therai.org.uk/at/debate)
Authors: Duschinski Haley , Hoffman Bruce
Published: October 2011

This article analyzes the role of Kashmiri lawyers working in a context of conflict, militarization and political resistance in Kashmir Valley, India. It finds that the Kashmir Bar Association, operating under conditions of state control that are maintained and legitimized through the law, constitutes an authoritative normative community and powerful institutional actor, working within the parameters of the Indian legal system while simultaneously supporting and maintaining solidarity with the movement for self‐determination, and contesting the legitimacy of Indian state rule. The association's decidedly moral vision of the law offers an alternative form of legal imagination that draws on transnational normative frameworks and practices to challenge the legal provisions and legal failures that function to legitimize human‐rights violations taking place under conditions of militarization. As we show in this article, the recent crisis period in Kashmir has posed challenges to KBA lawyers, as they negotiate and assess their relationship to the state, their place in the struggle for self‐determination, and the promise and potency of law as a strategy for social change.
Negotiating human research ethics: Case notes from anthropologists in the field (Respond to this article at http://www.therai.org.uk/at/debate)
Authors: Chenhall Richard , Senior Kate , Belton Suzanne
Published: October 2011

The human ethics issues surrounding the conduct of health science research have been the subject of increasing debate among biomedical and social science researchers in recent years. Ethics procedures in health‐science research are typically concerned with protecting anonymity and confidentiality, and are tailored to work that primarily uses quantitative methodologies. For qualitative research in the health social sciences, a different set of ethical issues often arises in the research process. This article examines three case studies of qualitative researchers working with Indigenous Australian communities, focusing on the researchers’ experiences with ethics committees and how they approached a range of ethical issues arising in the course of their research. Key issues include: obtaining informed consent for participant observation; the evolving nature of qualitative research; the difficulties in foreseeing changes in approach; and the distinction between the research team and the researched in participatory action research.
Organised Interests, Authority Structures and Political Influence: Danish and Norwegian Patient Groups Compared
Authors: Opedal Ståle , Rommetvedt Hilmar , Vrangbæk Karsten
Published: October 2011

The article presents a comparative analysis of the strategies applied by Danish and Norwegian patient organisations and organisations for disabled persons in order to promote the interests of their members. Three research questions are addressed: Are Danish and Norwegian patient organisations service organisations operating according to a ‘logic of membership’ or political pressure groups acting according to a ‘logic of influence’? Do patient organisations apply ‘insider’ or ‘outsider’ strategies in their efforts to influence healthcare policies? What impact do different authority structures have on the patient organisations' influencing strategies? The latter question is related to recent reforms in the public healthcare systems of the two countries. The major responsibility for public hospitals now rests with regional authorities in Denmark and central government in Norway. The study is based on a survey among nationwide patient organisations in the two countries and shows that most patient groups are ‘polyvalent’‘venue shoppers’ combining a variety of influencing strategies.