bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric organic nitrogen deposition explored at workshop
Authors: Church Thomas M.
Published: October 2011

Atmospheric organic nitrogen (AON) is an important nitrogen component with significant deposition in many natural waters. The range and quality of the data are varied, but deposited organic nitrogen (DON) is ubiquitous globally, both in extent and magnitude.

The Environmental Protection Agency's Chesapeake Bay Program (CBP) sponsored a workshop last year to determine what is known about organic nitrogen in atmospheric deposition and to establish research priorities needed to obtain an adequate database for coastal waters such as Chesapeake Bay Working groups at the meeting concluded that AON represents a poorly quantified array of broadly reactive natural and pollutant species; that because of compromises in collection, preservation, and analysis, wet deposition of total organic nitrogen is inadequately quantified and dry deposition is not quantified at all; and that because of a lack of data on bioactive species, the effect of AON and DON on ecosystems is largely unknown.
Ice thickness derived from high‐resolution radar imagery
Authors: Kwok Ron , Cunningham Glenn F. , LaBelle‐Hamer Nettie , Holt Benjamin , Rothrock Drew
Published: October 2011

A new analysis makes it possible to produce basin‐scale estimates of sea ice age and thickness from observations of ice motion in radar images of the Arctic Ocean. Anticipated from sequential synthetic aperture radar (SAR) imagery over a series of winters are Arcticwide fields of ice motion and estimates of ice age and thickness. This analysis technique is implemented in the RADARSAT Geophysical Processor System (RGPS),a data processing system dedicated to analyzing large volumes of SAR imagery of sea ice [Kwok, 1998].

Currently, we have only crude estimates on how much ice there is, how it varies in space and time, where ice is produced and where it melts, and how rapidly it is transported from place to place. SAR provides an amazingly detailed look at sea ice, but the level of detail is so great that it is not at first apparent how to utilize the data for improving sea ice data sets and models.
Research in Great Australian Bight yields exciting early results
Authors: Hine Albert C. , Feary David A. , Malone Mitchell J. ,   Leg 182 Shipboard Party
Published: October 2011

Confirmation that Pleistocene mound features underlying the outer shelf and shelf edge are bryozoan buildups—effectively coolwater reefs—was one of several exciting discoveries during recent research earlier this year on the Great Australian Bight. Also found on Ocean Drilling Program (ODP) Leg 182 was startling evidence of high salinity fluid circulation within the shelf substrate, producing extremely high methane and hydrogen sulfide gas levels and accelerated diagenesis.

In addition, an expanded middle Eocene to early Oligocene record of Southern Ocean initiation was recovered by the shipboard scientific party, aboard the JOIDES Resolution. The group also calculated unexpectedly high rates of shelf edge cool‐water carbonate accumulation (up to 40 cm/kyr).
Origin, effects of Masaya Volcano's continued unrest probed in Nicaragua
Authors: Delmelle Pierre , Baxter Peter , Beaulieu Alex , Burton Mike , Francis Peter , Garcia‐Alvarez Julios , Horrocks Lisa , Navarro Martha , Oppenheimer Clive , Rothery Dave , Rymer Hazel , St. Amand Katie , Stix John , Strauch Wilfried , Williams‐Jones Glyn
Published: October 2011

An international team of researchers is hoping to pin down the origin and determine the effects of 6 years of continued unrest at Nicaragua's Masaya volcano. With the country's capital, Managua, close by, several million people are at risk if a large, explosive eruption were to occur.

Masaya is distinctive not only for its explosive basaltic eruptions of the past, but also for its postcaldera activity. Combined geophysical and geochemical surveys are improving understanding of volcanic activity there, and new techniques are providing exciting inroads into deciphering the atmospheric chemistry in its plume dispersal, addressing the nature of relatively rapid variations in its gas emission rates, and monitoring its gas hazards. Many issues remain to be resolved, however.
Water and wars
Authors: Gleick Peter H.
Published: October 2011

In “Challenging the Rhetoric of Water Wars” (Eos, In Brief, September 5, 2000, p. 410) Randy Showstack reported on the speech given by Minister Kader Asmal upon receiving the 2000 Stockholm Water Prize. This prize was well deserved for the tremendous progress South Africa has made under Minister Asmal's leadership in addressing basic water needs after apartheid. Indeed, I was one of his nominators for this prize and am an ardent fan of his bold programs. But his remarks about water‐related conflicts need to be qualified. In his speech, Minister Asmal noted that water scarcity is a “crisis of biblical proportion,” but also suggested “there is not a shred of evidence” to back up arguments that there are water “wars.”
Alaskan Glacier beats a dramatic retreat
Authors: Pfeffer W.T. , Cohn J. , Meier M. , Krimmel R. M.
Published: October 2011

The spectacular fjords of the south‐central and southeast coasts of Alaska are, in addition to being popular tourist attractions, testimonials to the power of glacial erosion and the speed of calving glacier retreat.

Within the past 100 to 400 years, most of the present‐day fjords of Alaska were occupied by tidewater glaciers at extended coastal positions. But elevated iceberg calving rates forced glacier termini back dramatically in the late 19th century One example is the Grand Pacific glacier, which retreated 33 km in just 20 years through Tarr Inlet in Glacier Bay
Shuttle radar topography mission produces a wealth of data
Authors: Farr Tom G. , Kobrick Mike
Published: October 2011

On February 22, 2000, the Space Shuttle Endeavour landed at Kennedy Space Center, completing the highly successful 11‐day flight of the Shuttle Radar Topography Mission (SRTM). Onboard were over 300 high‐density tapes containing data for the highest resolution digital topographic map of Earth ever made.

SRTM is a cooperative project between the National Aeronautics and Space Administration (NASA) and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense. The mission was designed to use a single‐pass radar interferometer to produce a digital elevation model (DEM) of the Earth's land surface between about 60 north and 56 south latitude. When completed, the DEM will have 30‐m pixel spacing and about 15‐m vertical accuracy. Two ortho‐rectified image mosaics, one from the ascending passes with illumination from the southeast, and one from descending passes with illumination from the southwest, will also be produced (Figure 1).
Research Spotlight: Complexities of aquifer systems complicate reaction rate estimates
Authors: Ofori Leslie , Tretkoff Ernie
Published: October 2011

Contaminant concentrations in aquifers can change as chemical reactions occur during groundwater transport through the aquifer. For instance, denitrification, in which the contaminant nitrate (NO3) is converted to molecular nitrogen (N2), reduces NO3 contaminant loads. It is useful to understand the rates at which denitrification and other reactions occur in an aquifer to improve understanding and prediction of contaminant migration.
Bak Foong Pills induce an analgesic effect by inhibiting nociception via the somatostatin pathway in mice
Authors: Rowlands Dewi Kenneth , Cui Yu Gui , So Siu Cheung , Tsang Lai Ling , Chung Yiu Wa , Chan Hsiao Chang
Published: October 2011

Dysmenorrhoea, defined as cramping pain in the lower abdomen occurring before or during menstruation, affects, to varying degrees, up to 90% of women of child‐bearing age. We investigated whether BFP (Bak Foong Pills), a traditional Chinese medicine treatment for dysmenorrhoea, possesses analgesic properties. Results showed that BFP was able to significantly reduce pain responses following subchronic treatment for 3 days, but not following acute (1 h) treatment in response to acetic acid‐induced writhing in C57/B6 mice. The analgesic effect was not due to inhibition of COX (cyclo‐oxygenase) activity, evidenced by the lack of inhibition of prostacyclin and PGE2 (prostaglandin E2) production. Molecular analysis revealed that BFP treatment modulated the expression of a number of genes in the spinal cord of mice subjected to acetic acid writhing. RT—PCR (reverse transcription—PCR) analysis of spinal cord samples showed that both sst4 (somatostatin receptor 4) and sst2 receptor mRNA, but not μOR (μ‐opiate receptor) and NK1 (neurokinin‐1) receptor mRNA, were down‐regulated following BFP treatment, thus implicating somatostatin involvement in BFP‐induced analgesia. Administration of c‐som (cyclo‐somatostatin), a somatostatin antagonist, prior to acetic acid‐induced writhing inhibited the analgesic effect. Thus subchronic treatment with BFP has anti‐nociceptive qualities mediated via the somatostatin pathway.
Perforin is recaptured by natural killer cells following target cells stimulation for cytotoxicity
Authors: Wang Lei , Sun Rulin , Li Pan , Han Yang , Xiong Ping , Xu Yong , Fang Min , Tan Zheng , Zheng Fang , Gong Feili
Published: October 2011

When encountering target cells, NK (natural killer) cells exocytose Pfn (perforin) and granzyme B to kill challengers. We previously reported that granzyme B is recycled and reused by NK cells via clathrin‐dependent endocytosis. However, whether Pfn, a main secretory vesicle content, indispensible to granzyme B killing, undergoes endocytosis remains unknown. We demonstrate that Pfn is recaptured by early endosomes of NK cells via a clathrin‐dependent endocytosis after target cell stimulation. Inhibition of clathrin‐dependent endocytosis significantly attenuated the cytotoxicity of NK cells. The data suggest that the recovery of Pfn contributes to the cytotoxicity of NK cells. The assay of endocytosis of lytic molecule presents a particular focus for exploring the mechanism of abnormal cytotoxicity of NK cells.
Effects of SIRT6 silencing on collagen metabolism in human dermal fibroblasts
Authors: Baohua Yang , Li Li
Published: October 2011

SIRT6 (sirtuin 6) has been identified as an anti‐aging protein, and SIRT6‐deficient mice display numerous progeroid and aging‐like phenotypes. However, there are no reports correlating skin aging with SIRT6. To explore how SIRT6 affects collagen metabolism and determine its role in skin aging, the levels of COL1A1 (type I collagen), COL3A1 (type III collagen) and TGFβ1 (transforming growth factor β1) mRNA expression were detected by RT‐Q‐PCR (real‐time quantitative PCR), and MMP1 (matrix metalloproteinase 1) concentration in HDF (human dermal fibroblast) supernatants was determined by ELISA after blocking SIRT6 using siRNA (small interefering RNA). Compared with the control group, blocking SIRT6 significantly decreased the HC (hydroxyproline content). SIRT6 knockdown in HDFs inhibited the transcription of COL1A1 and prompted MMP1 secretion, but had no effect on COL3A1 and TGFβ1. Furthermore, NF‐κB p65 (nuclear factor κB p65) protein in the nucleus was increased after blocking SIRT6. The results suggest that SIRT6 knockdown in HDFs influence the synthesis and degradation of collagen by hyperactive NF‐κB signalling, which leads to a decrease in dermal collagen fibrils. SIRT6 may therefore play an important role in the process of skin anti‐aging.
The Best of Both Worlds: Combining Synchronous and Asynchronous Telepractice in the Treatment of Aphasia
Authors: Cherney Leora R. , Kaye Rosalind C. , Hitch Rachel S.
Published: October 2011

Telepractice is an appropriate model of service delivery for a person with aphasia (PWA). We define telepractice and its two modes of delivery (i.e., synchronous and asynchronous). We detail a technology, web-Oral Reading for Language in Aphasia (web-ORLA™), developed to provide aphasia treatment intensively from a distance and subsequently evaluated during a clinical trial. In this article, we describe our experiences using web-ORLA™, highlighting the role of the speech-language pathologist (SLP) and discussing the advantages and disadvantages of this unique combination of synchronous and asynchronous telepractice. Web-ORLA™ was delivered to PWAs in their homes by a digital agent, or “virtual therapist,” who served as a model and provided instructions similarly to a real therapist. An SLP at a distant geographical location monitored the sessions remotely, either synchronously or asynchronously, provided feedback, made appropriate adjustments to the difficulty level of the stimuli, and conducted weekly probe assessments of the participants' performance. Advantages of web-ORLA™ include increased practice, SLP oversight, guidance by the agent, program simplicity, and a level of autonomy and flexibility afforded to the PWA. Given the rapid advances in technology, current technological problems that were encountered are likely to be mitigated.
The Effect of Choice on Compliance Using Telerehabilitation for Direct Attention Training: A Comparison of “Push” Versus “Pull” Scheduling
Authors: Sohlberg McKay Moore , Lemoncello Rik , Lee Jaime
Published: October 2011

Home practice, a type of asynchronous telerehabilitation, is an integral component of most rehabilitation regimens. Exercise drills conducive to home practice have been shown to be beneficial in remediating acquired impairments in attention, speech, language, and voice. A variety of interacting psychological, cognitive, and socioenvironmental factors contribute to short- and long-term exercise adherence. There has been little research evaluating the personal characteristics most likely to motivate clients to engage in their rehabilitation and follow through with prescribed activities. In this project, we were interested in using telerehabilitation to learn more about factors that might increase clients' adherence to home exercise; we used direct attention training as our experimental domain. The study used a single-subject, alternating treatment experimental design with 2 participants to compare compliance on home attention exercises under two conditions. The Attention Process Training-3 (APT-3, 2010) direct attention training program, delivered via the Televised Assistance Program (TAP) system, allowed us to compare compliance under (a) conditions when the client had no control over the start-up of the program (push) versus (b) conditions when the client had to initiate turning on the program to do the home program (pull). Results showed that home exercise adherence was higher for both participants under the nonautonomous push condition. This ran counter to our hypothesis, based on the therapy literature, that suggested patients are more likely to follow through with home assignments when practice is under their control. We discuss our findings with respect to the interaction between self-efficacy, therapy beliefs, and autonomy for patients with acquired brain injury.
Density and temperature measurement of OH radicals in atmospheric-pressure pulsed corona discharge in humid air
Authors: Nakagawa Yusuke , Ono Ryo , Oda Tetsuji
Published: October 2011

Plasma application for environmental improvement is desirable, and it is worthwhile to clarify the behavior of OH radicals in nonthermal plasma. Under atmospheric-pressure humid air, the time evolutions and spatial distribution of relative density and rotational temperature of OH radicals are measured in pulsed positive corona discharge using laser-induced fluorescence with a tunable optical parametric oscillator laser. The density of OH radicals generated by discharge when 28 kV is applied is estimated to be about 1×1015cm-3 at 3 μs after discharge. The OH density increases with humidity. The rotational temperature rises after discharge. The rate of temperature rise increases with humidity. This phenomenon arises from fast vibration-to-translation energy relaxation of H2O. The spatial distributions of OH rotational temperature indicate that the temperature rises in the secondary streamer channel.
Hard x-ray photoelectron spectroscopy study of the buried Si/ZnO thin-film solar cell interface: Direct evidence for the formation of Si–O at the expense of Zn-O bonds
Authors: Wimmer M. , Bär M. , Gerlach D. , Wilks R. G. , Scherf S. , Lupulescu C. , Ruske F. , Félix R. , Hüpkes J. , Gavrila G. , Gorgoi M. , Lips K. , Eberhardt W. , Rech B.
Published: October 2011

The chemical structure of the interface between silicon thin films and the transparent conductive oxide ZnO:Al has been investigated by hard x-ray photoelectron spectroscopy. By varying the excitation energy between 2010 and 8040 eV, we were able to probe the Si/ZnO interface buried below 12 nm Si. This allowed for the identification of changes induced by solid phase crystallization (SPC). Based on in-situ SPC annealing experiments, we find clear indications that the formation of Si–O bonds takes place at the expense of Zn–O bonds. Hence, the ZnO:Al acts as the oxygen source for the interfacial Si oxidation.
Bounds on strong field magneto-transport in three-dimensional composites
Authors: Briane Marc , Milton Graeme W.
Published: October 2011

This paper deals with bounds satisfied by the effective non-symmetric conductivity of three-dimensional composites in the presence of a strong magnetic field. On the one hand, it is shown that for general composites the antisymmetric part of the effective conductivity cannot be bounded solely in terms of the antisymmetric part of the local conductivity, contrary to the columnar case studied by Briane and Milton [SIAM J. Appl. Math. 70(8), 3272–3286 (2010)10.1137/100798090]. Thus a suitable rank-two laminate, the conductivity of which has a bounded antisymmetric part together with a high-contrast symmetric part, may generate an arbitrarily large antisymmetric part of the effective conductivity. On the other hand, bounds are provided which show that the antisymmetric part of the effective conductivity must go to zero if the upper bound on the antisymmetric part of the local conductivity goes to zero, and the symmetric part of the local conductivity remains bounded below and above. Elementary bounds on the effective moduli are derived assuming the local conductivity and the effective conductivity have transverse isotropy in the plane orthogonal to the magnetic field. New Hashin-Shtrikman type bounds for two-phase three-dimensional composites with a non-symmetric conductivity are provided under geometric isotropy of the microstructure. The derivation of the bounds is based on a particular variational principle symmetrizing the problem, and the use of Y-tensors involving the averages of the fields in each phase.
Toroidal rotation and radial electric field driven by the lower-hybrid-wave in a tokamak fusion reactor
Authors: Wang Shaojie
Published: October 2011

A theoretical model is proposed to interpret the counter-current rotation driven by the lower-hybrid-wave observed in the tokamak lower-hybrid-wave parallel current drive experiments. It is found that ions absorb the toroidal momentum indirectly from the wave through collisional friction with the resonant electrons that directly take the momentum from the wave through Landau resonance. This momentum coupling pumps out the ions to produce a negative radial electric field and makes the plasma rotate in the counter-current direction.
Nonlinear behavior of electron acoustic waves in an un-magnetized plasma
Authors: Dutta Manjistha , Chakrabarti Nikhil , Roychoudhury Rajkumar , Khan Manoranjan
Published: October 2011

The nonlinear electron acoustic wave, which is found in the earth’s magnetosphere by satellite observations, is studied analytically by Lagrangian fluid description. The basic linear mode is observed in a two temperature electron species plasma where ions form stationary charge neutral background. We have obtained nonlinear description of this mode, which depends on both time and space. A possible solution shows a soliton like structure, which is localized in space, and the amplitude increases with time in the absence of dispersion. Small dispersive correction, however, shows spread of the solution in space. This method can be generalized to study the nonlinear behavior of a general class of multispecies plasma.
Alloying effects on the elastic parameters of ferromagnetic and paramagnetic Fe from first-principles theory
Authors: Zhang H. L. , Al-Zoubi N. , Johansson B. , Vitos L.
Published: October 2011

The elastic properties of paramagnetic face-centered-cubic (fcc) Fe1-xMx (M = Al, Si, V, Cr, Mn, Co, Ni, and Rh; 0 ≤ x ≤ 0.1) random alloys are investigated using the exact muffin-tin orbitals density functional method in combination with the coherent-potential approximation. We find that the theoretical lattice parameter of fcc Fe is strongly enlarged by Al, V, and Rh and slightly reduced by Si, Cr, and Co, while it remains nearly constant with Mn and Ni. Both positive and negative alloying effects appear for the elastic constants Cij(x) of fcc Fe. These findings are in contrast to those obtained for ferromagnetic body-centered-cubic (bcc) Fe alloys, where all alloying elements considered here are predicted to enlarge the lattice parameter and decrease the C11(x) and C12(x) elastic constants of bcc Fe. With some exceptions, alloying has much larger effects on ferromagnetic bcc alloys than on paramagnetic fcc ones. Based on the theoretical elastic parameters of the paramagnetic fcc and ferromagnetic bcc phases, simple parameterizations in terms of chemical composition of the equilibrium lattice constants, single-crystal elastic constants, and polycrystalline elastic moduli of Fe-based alloys are presented.
Micro-scale measurement and modeling of stress in silicon surrounding a tungsten-filled through-silicon via
Authors: Koseski Ryan P. , Osborn William A. , Stranick Stephan J. , DelRio Frank W. , Vaudin Mark D. , Dao Thuy , Adams Vance H. , Cook Robert F.
Published: October 2011

The stress in silicon surrounding a tungsten-filled through-silicon via (TSV) is measured using confocal Raman microscopy line scans across the TSV both before and after etch removal of an oxide stack used as a mask to define the TSV during fabrication. Stress in the silicon arose in response to both athermal deposition and thermal expansion mismatch effects. The complex three-dimensional stress and strain field in silicon surrounding the TSV is modeled using finite element analysis, taking into account both athermal and thermal effects and the elastic anisotropy of silicon. Comparison of the measurements and model results shows that no one component of the stress tensor correlates with the Raman peak shift generated by the deformed silicon. An analysis is developed to predict the Raman shift in deformed silicon that takes into account all the components of the stress or strain tensor; the results of the model are then used as inputs to the analysis for direct comparison with measured peak shifts as a function of distance from the TSV. Good agreement between the measured and predicted peak shifts is obtained for the case of the intact oxide stack. A discrepancy between the measured and predicted shifts was observed adjacent to the TSV with the oxide stack removed; further modeling suggests the discrepancy is explained by the formation of a small void at the TSV-silicon interface during etching. The combined measurement-modeling approach serves to both validate the model, in this case for TSV design, and to extend the measurement capability of confocal Raman microscopy to complex stress fields.
Metrics for comparing plasma mass filters
Authors: Fetterman Abraham J. , Fisch Nathaniel J.
Published: October 2011

High-throughput mass separation of nuclear waste may be useful for optimal storage, disposal, or environmental remediation. The most dangerous part of nuclear waste is the fission product, which produces most of the heat and medium-term radiation. Plasmas are well-suited to separating nuclear waste because they can separate many different species in a single step. A number of plasma devices have been designed for such mass separation, but there has been no standardized comparison between these devices. We define a standard metric, the separative power per unit volume, and derive it for three different plasma mass filters: the plasma centrifuge, Ohkawa filter, and the magnetic centrifugal mass filter.
Dissociative double photoionization of singly deuterated benzene molecules in the 26–33 eV energy range
Authors: Alagia M. , Candori P. , Falcinelli S. , Mundim M. S. P. , Pirani F. , Richter R. , Rosi M. , Stranges S. , Vecchiocattivi F.
Published: October 2011

This work provides new experimental and theoretical results about the formation and dissociation of benzene dication. The experiment has been carried out by using a vacuum ultraviolet radiation from a synchrotron source together with a time-of-flight spectrometer and a position sensitive ion detector. Isotopically labeled benzene molecules with a single deuterium atom have been used in order to study the symmetric dissociation of the benzene dication, not well evident in previous experiments. A threshold of 30.1 ± 0.1 eV has been observed for this dissociation reaction. Moreover, the lifetime of the dissociation of the benzene metastable dication producing CH3+ and C5H3+ has been obtained as a function of the photon energy, by the use of a Monte Carlo trajectory analysis of the coincidence distributions. The determined lifetime is independent of the photon energy and has an average value of 0.75 ± 0.22 μs. Theoretical calculations of the energy and structure of dissociation product ions have been also performed to provide crucial information about the dynamics of the charge separation reactions following the photoionization event.
Multiple dielectric transitions in the PbTiO3-Bi(Zn1/2Ti1/2)O3-Bi(Mg1/2Ti1/2)O3 system
Authors: Stein David M. , Grinberg Ilya , Rappe Andrew M. , Davies Peter K.
Published: October 2011

The ternary perovskite system PbTiO3-Bi(Zn1/2Ti1/2)O3-Bi(Mg1/2Ti1/2)O3 was investigated in an attempt to capture the enhanced tetragonality of the PbTiO3-Bi(Zn1/2Ti1/2)O3 binary system at a morphotropic phase boundary (MPB) to improve piezoelectric performance. Results from the (1−x)[0.75 PbTiO3-0.25Bi(Zn1/2Ti1/2)O3]-(x)Bi(Mg1/2Ti1/2)O3 pseudo-binary solution indicate the formation of an MPB-type phase boundary with a high TC (585 °C at x = 0.55). Multiple dielectric transitions were observed in a region of the ternary diagram characterized by high occupancy of the A-site by Bi3+ (>40%) and the B-site by ferroelectrically active cations (>70%). Temperature-dependent diffraction studies revealed the persistence of a tetragonal structure in at least a subset of the crystal to the higher temperature dielectric transition.
An overlap fitted chain of spheres exchange method
Authors: Izsák Róbert , Neese Frank
Published: October 2011

The “chain of spheres” (COS) algorithm, as part of the RIJCOSX SCF procedure, approximates the exchange term by performing analytic integration with respect to the coordinates of only one of the two electrons, whereas for the remaining coordinates, integration is carried out numerically. In the present work, we attempt to enhance the efficiency of the method by minimizing numerical errors in the COS procedure. The main idea is based on the work of Friesner and consists of finding a fitting matrix, \documentclass[12pt]{minimal}\begin{document}$\mathbf {Q}$\end{document}Q, which leads the numerical and analytically evaluated overlap matrices to coincide. Using \documentclass[12pt]{minimal}\begin{document}$\mathbf {Q}$\end{document}Q, the evaluation of exchange integrals can indeed be improved. Improved results and timings are obtained with the present default grid setup for both single point calculations and geometry optimizations. The fitting procedure results in a reduction of grid sizes necessary for achieving chemical accuracy. We demonstrate this by testing a number of grids and comparing results to the fully analytic and the earlier COS approximations. This turns out to be favourable for total and reaction energies, for which chemical accuracy can now be reached with a corresponding ∼30% speedup over the original RIJCOSX procedure for single point energies. Results are slightly less favourable for the accuracy of geometry optimizations, but the procedure is still shown to yield geometries with errors well below the method inherent errors of the employed theoretical framework.
The effects of shape and flexibility on bio-engineered fd-virus suspensions
Authors: Dennison M. , Dijkstra M. , van Roij R.
Published: October 2011

We present a theoretical model to describe binary mixtures of semi-flexible rods, applied here to fd-virus suspensions. We investigate the effects of rod stiffness on both monodisperse and binary systems, studying thick-thin and long-short mixtures. For monodisperse systems, we find that fd-virus particles have to be made extremely stiff to even approach the behavior of rigid rods. For thick-thin mixtures, we find increasingly rich phase behavior as the rods are either made more flexible or if their diameter ratio is increased. For long-short rod mixtures we find that the phase behavior is controlled by the relative stiffness of the rods, with increasing the stiffness of the long rods or decreasing that of the short rods resulting in richer phase behavior. We also calculate the state point dependent effective shape of the rods. The flexible rods studied here always behave as shorter, thicker rigid rods, but with an effective shape that varies widely throughout the phase diagrams, and plays a key role in determining phase behavior.
Modification of electrical properties of Al/p-Si Schottky barrier device based on 2′-7′-dichlorofluorescein
Authors: Soylu Murat , Yahia I. S. , Yakuphanoglu Fahrettin , Farooq W. A.
Published: October 2011

The charge conduction mechanism and electrical properties of Al/p-Si Schottky barrier device based on 2′-7′-dichlorofluorescein (DCF) were investigated by current density–voltage (J–V) and capacitance–voltage (C–V) methods. Thin film of DCF organic compound was deposited on p-Si substrate as an interfacial layer by spin-coating technique. The dark J–V characteristics indicate that the rectifying junction is formed at DCF/Al interface. The ideality factor and barrier height of the Al/DCF/p-Si Schottky diode are higher than that of Al/p-Si Schottky diode. The effect of the thickness of the DCF organic layer was investigated by evaluating electrical parameters, such as the barrier height, ideality factor, series resistance, and interface state density. It is seen that the thickness of the DCF layer significantly affects the electrical properties by influencing the space charge region of the Al/DCF/p-Si Schottky junction. The interface state density of the diode was determined using low-high frequency C–V plots and was of order of ≈1011 eV−1cm−2. The order of the interface state density of Al/DCF/p-Si is lower than most of metal/organic compound/inorganic semiconductor devices. The values of the barrier height of the studied diodes are significantly larger than those of conventional Al/p-Si Schottky diodes. The J–V curves in the reverse direction are taken and interpreted via both Schottky and Poole–Frenkel effects. Poole–Frenkel effect was found to be dominant in the reverse direction.
On the dynamics and breakup of a bubble rising in a turbulent flow
Authors: Ravelet F. , Colin C. , Risso F.
Published: October 2011

Experimental investigations of the dynamics of a deformable bubble rising in a uniform turbulent flow are reported. The turbulence is characterized by fast particle image velocimetry. Time-resolved evolutions of bubble translation, rotation, and deformation are determined by three-dimensional shape recognition from three perpendicular camera views. The bubble dynamics involves three mechanisms fairly decoupled: (1) average shape is imposed by the mean motion of the bubble relative to liquid; (2) wake instability generates almost periodic oscillations of velocity and orientation; (3) turbulence causes random deformations that sometimes lead to breakup. The deformation dynamics is radically different from that observed in the absence of a significant sliding motion due to buoyancy. Large deformations that lead to breakup are not axisymmetric and correspond to elongations in the horizontal direction. The timescale of decay of shape oscillations is of the same order as their natural frequency f2, so that breakup always results from the interaction with a single turbulent eddy. This overdamping causes the statistics of large deformations and the statistics of breakup identical to the statistics of turbulence. The bubble response time f2-1 however controls the duration of individual breakup events.
Slip flow in graphene nanochannels
Authors: Kannam Sridhar Kumar , Todd B. D. , Hansen J. S. , Daivis Peter J.
Published: October 2011

We investigate the hydrodynamic boundary condition for simple nanofluidic systems such as argon and methane flowing in graphene nanochannels using equilibrium molecular dynamics simulations (EMD) in conjunction with our recently proposed method [J. S. Hansen, B. D. Todd, and P. J. Daivis, Phys. Rev. E 84, 016313 (2011)10.1103/PhysRevE.84.016313]. We first calculate the fluid-graphene interfacial friction coefficient, from which we can predict the slip length and the average velocity of the first fluid layer close to the wall (referred to as the slip velocity). Using direct nonequilibrium molecular dynamics simulations (NEMD) we then calculate the slip length and slip velocity from the streaming velocity profiles in Poiseuille and Couette flows. The slip lengths and slip velocities from the NEMD simulations are found to be in excellent agreement with our EMD predictions. Our EMD method therefore enables one to directly calculate this intrinsic friction coefficient between fluid and solid and the slip length for a given fluid and solid, which is otherwise tedious to calculate using direct NEMD simulations at low pressure gradients or shear rates. The advantages of the EMD method over the NEMD method to calculate the slip lengths/flow rates for nanofluidic systems are discussed, and we finally examine the dynamic behaviour of slip due to an externally applied field and shear rate.
Influence of bending strains on radio frequency characteristics of flexible microwave switches using single-crystal silicon nanomembranes on plastic substrate
Authors: Qin Guoxuan , Yuan Hao-Chih , Celler George K. , Ma Jianguo , Ma Zhenqiang
Published: October 2011

This letter presents radio frequency (RF) characterization of flexible microwave switches using single-crystal silicon nanomembranes (SiNMs) on plastic substrate under various uniaxial mechanical tensile bending strains. The flexible switches shows significant/negligible performance enhancement on strains under on/off states from dc to 10 GHz. Furthermore, an RF/microwave strain equivalent circuit model is developed and reveals the most influential factors, and un-proportional device parameters change with bending strains. The study demonstrates that flexible microwave single-crystal SiNM switches, as a simple circuit example towards the goal of flexible monolithic microwave integrated circuits, can be properly operated and modeled under mechanical bending conditions.
Optimal laser wavelength for photoacoustic imaging of breast microcalcifications
Authors: Kang Jeeun , Kim Eun-Kyung , Young Kwak Jin , Yoo Yangmo , Song Tai-Kyong , Ho Chang Jin
Published: October 2011

This paper presents photoacoustic imaging (PAI) for real-time detection of micro-scale calcifications (e.g., <1 mm) in the breast, which are an indicator of the cancer occurrence. Optimal wavelength of incident laser for the microcalcification imaging was ascertained through ex vivo experiments with seven breast specimens of volunteers. In the ex vivo experiments, the maximum amplitude of photoacoustic signals from the microcalcifications occurred when the laser wavelength ranged from 690 to 700 nm. This result demonstrated that PAI can serve as a real-time imaging and guidance tool for diagnosis and biopsy of the breast microcalcifications.
Communication: Quantitative Fourier-transform infrared data for competitive loading of small cages during all-vapor instantaneous formation of gas-hydrate aerosols
Authors: Uras-Aytemiz Nevin , Abrrey Monreal I. , Devlin J. Paul
Published: October 2011

A simple method has been developed for the measurement of high quality FTIR spectra of aerosols of gas-hydrate nanoparticles. The application of this method enables quantitative observation of gas hydrates that form on subsecond timescales using our all-vapor approach that includes an ether catalyst rather than high pressures to promote hydrate formation. The sampling method is versatile allowing routine studies at temperatures ranging from 120 to 210 K of either a single gas or the competitive uptake of different gas molecules in small cages of the hydrates. The present study emphasizes hydrate aerosols formed by pulsing vapor mixtures into a cold chamber held at 160 or 180 K. We emphasize aerosol spectra from 6 scans recorded an average of 8 s after “instantaneous” hydrate formation as well as of the gas hydrates as they evolve with time. Quantitative aerosol data are reported and analyzed for single small-cage guests and for mixed hydrates of CO2, CH4, C2H2, N2O, N2, and air. The approach, combined with the instant formation of gas hydrates from vapors only, offers promise with respect to optimization of methods for the formation and control of gas hydrates.
Constraints on establishing threshold levels for Warner - Bratzler shear-force values based on consumer sensory ratings for seven beef muscles
Authors: Powell L. , Nicholson K. L. , Huerta-Montauti D. , Miller R. K. , Savell J. W.
Published: October 2011

Steaks (n = 560) from US Department of Agriculture (USDA) Choice and Select, including M. gluteobiceps, M. gluteus medius, M. infraspinatus, M. longissimus lumborum, M. rectus femoris, M. triceps brachii and M. vastus lateralis, were evaluated for palatability characteristics and tenderness acceptability by a central-location consumer panel (n = 205 consumers) and Warner–Bratzler shear (WBS) analysis to determine whether threshold values could be identified for these muscles. There were significant interactions for muscle × USDA quality grade for sensory-panel overall like and WBS values. In general, USDA quality grade affected overall like and WBS values for the M. gluteobiceps and M. rectus femoris, but no real differences due to grade were found for the rest of the muscles studied, except for the WBS values for the M. gluteus medius. Regardless of USDA quality grade, the M. infraspinatus had the lowest (P < 0.05) WBS values and was comparable (P > 0.05) in overall like ratings to the M. longissimus lumborum. Percentage of muscles that would be expected to have a tenderness rating ‘slightly tender’ or higher on the basis of WBS values at the 95% confidence interval ranged from 40% for the M. vastus lateralis to 100% for the M. infraspinatus. There were no clear threshold levels for WBS values that would correspond to certain tenderness like ratings, possibly because of the narrow range of tenderness observed within each muscle. For the muscles studied, how consumers rated them appeared to be independent of the WBS values and may make it difficult to develop WBS thresholds for predicting consumer acceptability of these muscles.
The effect of annual shearing time on wool production by a spring-lambing Merino flock in south-eastern Australia
Authors: Campbell A. J. D. , Larsen J. W. A. , Vizard A. L.
Published: October 2011

Time of shearing affects many aspects of wool production and sheep health but no study has examined these factors concurrently in a spring-lambing, self-replacing Merino flock in southern Australia. A 5-year field experiment compared wool production in spring-lambing Merino ewes and their progeny shorn at different times and managed under commercial conditions in south-eastern Australia. Groups of 200 adult ewes were shorn in December, March or May, and their progeny were shorn in December or October, March or June, or May or July, respectively. There was no consistent association between time of shearing and the staple strength of wool (P = 0.73). December-shorn ewes produced significantly lighter and finer fleeces (average 19.1 μm, 3.0 kg clean weight) than did March-shorn ewes (19.4 μm, 3.1 kg). Fleeces from ewes shorn in May were of similar weight to those from March-shorn ewes (3.1 kg), but they were of significantly broader diameter (19.7 μm). In young sheep, desirable changes in some wool characteristics for each shearing group were offset by undesirable changes in others. On the basis of median historical (1991–2006) wool prices, shearing ewes in March and their progeny first in June produced the greatest total value of wool over a sheep’s lifetime ($161/head). The wool values per head for other shearing times were as follows: March (weaners)–March (ewes): $158; October–December: $157; December–December: $153; July–May: $151; and May–May: $148. Thus, December and March shearing were appropriate alternatives for maximising wool value produced from a self-replacing Merino flock in south-eastern Australia, whereas May was a less preferable shearing time because it always produced wool of lesser value.
Survival of twin lambs is increased with shrub belts
Authors: Robertson S. M. , Friend M. A. , Broster J. C. , King B. J.
Published: October 2011

Abstract
Perinatal lamb mortality is a major source of reproductive loss, particularly for twins. A study was conducted to determine whether provision of shelter in the form of shrub belts (a ‘maternity ward’) could increase survival of twin lambs compared with hedgerows, and whether hedgerows improve survival of single lambs compared with unsheltered paddocks. Measurements were recorded for Merino × Poll Dorset cross twin lambs born in hedgerows (phalaris or hessian) or shrub belts and single lambs born in hedgerows or unsheltered paddocks over the years 2007–2009. Records for 382 single and 726 twin lambs were used. The survival of single lambs was not increased (P = 0.06) by hedgerow shelter. The survival of twin lambs in shrubs was 10% higher (P < 0.05) than that in hessian hedgerow shelter in 2008–2009 (0.77 cf. 0.70), associated with a reduction in deaths from starvation and/or mismothering and/or exposure. The hessian shelter was associated with an increased (P < 0.05) growth rate to weaning of single lambs, but the growth rates of twin lambs were lower (P < 0.05) in shrub than in hessian shelter. In 2010, a second study of 178 twin Merino × Poll Dorset cross lambs found that survival of lambs born alive was not improved by shrubs compared with unsheltered paddocks (0.80 versus 0.77; P > 0.05). It is concluded that shrub belts which forced twin-bearing ewes to lamb in a sheltered environment reduced perinatal mortality in one of three datasets, but was not repeated. The shrubs take time to establish, and the benefit will be small if weather is mild during lambing.
Life history and population dynamics of invasive common carp, Cyprinus carpio, within a large turbid African impoundment
Authors: Winker Henning , Weyl Olaf L. F. , Booth Anthony J. , Ellender Bruce R.
Published: October 2011

As one of the most widely established freshwater fishes globally, the invasive success of common carp, Cyprinus carpio, is beyond dispute. Although detailed knowledge on its biology would assist in its management, relatively few life history studies have investigated C. carpio outside of its natural range. The present study analyses the life history and population structure of exotic C. carpio in a 364 km2 African impoundment. We used whole astericus otoliths to show that C. carpio attained ages of up to 7 years and grew more rapidly than has been recorded for any population from Europe or Australia. Macroscopic staging of gonads indicated protracted spawning, with highest reproductive activity observed during late spring and early summer. Total mortality, natural mortality and fishing mortality rates were estimated at 0.72, 0.60 and 0.12 year–1 respectively. Life history comparisons across the species’ global distribution showed large variations in growth and longevity, whereas early maturation (2–3 years) appeared to be a rather conservative trait. The combination of early maturity, fast growth and relatively high natural mortality rates suggests a rapid population growth potential associated with high resilience to management interventions once C. carpio has been introduced.
Oxidative stress induces overgrowth of theDrosophilaneuromuscular junction
Authors: Milton Valerie J. , Jarrett Helen E. , Gowers Kate , Chalak Salma , Briggs Laura , Robinson Iain M. , Sweeney Sean T.
Published: October 2011

Synaptic terminals are known to expand and contract throughout an animal's life. The physiological constraints and demands that regulate appropriate synaptic growth and connectivity are currently poorly understood. In previous work, we identified aDrosophilamodel of lysosomal storage disease (LSD),spinster(spin), with larval neuromuscular synapse overgrowth. Here we identify a reactive oxygen species (ROS) burden inspinthat may be attributable to previously identified lipofuscin deposition and lysosomal dysfunction, a cellular hallmark of LSD. Reducing ROS inspinmutants rescues synaptic overgrowth and electrophysiological deficits. Synapse overgrowth was also observed in mutants defective for protection from ROS and animals subjected to excessive ROS. ROS are known to stimulate JNK and fos signaling. Furthermore, JNK and fos in turn are known potent activators of synapse growth and function. Inhibiting JNK and fos activity inspinrescues synapse overgrowth and electrophysiological deficits. Similarly, inhibiting JNK, fos, and jun activity in animals with excessive oxidative stress rescues the overgrowth phenotype. These data suggest that ROS, via activation of the JNK signaling pathway, are a major regulator of synapse overgrowth. In LSD, increased autophagy contributes to lysosomal storage and, presumably, elevated levels of oxidative stress. In support of this suggestion, we report here that impaired autophagy function reverses synaptic overgrowth inspin.Our data describe a previously unexplored link between oxidative stress and synapse overgrowth via the JNK signaling pathway.
Small GTPase Rab5 participates in chromosome congression and regulates localization of the centromere-associated protein CENP-F to kinetochores
Authors: Serio Gaetana , Margaria Valentina , Jensen Sanne , Oldani Amanda , Bartek Jiri , Bussolino Federico , Lanzetti Letizia
Published: October 2011

Rab5 is a small GTPase known to regulate vesicular trafficking during interphase. Here, we show that Rab5 also plays an unexpected role during mitotic progression. RNAi-mediated silencing of Rab5 caused defects in chromosome congression and extensive prometaphase delay, and it correlated with a severe reduction in the localization of the centromere-associated protein CENP-F to kinetochores. CENP-F is a component of the nuclear matrix required for chromosome congression that, at mitotic entry, localizes to the nuclear envelope and assembles on kinetochores, contributing to the establishment of kinetochore microtubule interactions. We found that Rab5 forms a complex with a subset of CENP-F in mitotic cells and regulates the kinetics of release of CENP-F from the nuclear envelope and its accumulation on kinetochores. Simultaneous depletion of both Rab5 and CENP-F recapitulated the mitotic defects caused by silencing of either Rab5 or CENP-F alone, indicating epistatic roles for these two proteins in the pathway that orchestrates chromosome congression. These results reveal the involvement of Rab5 in the proper execution of mitotic programs whose deregulation can undermine chromosomal stability.