bluuebunny/crossref_metadata_2025 huggingface dataset:
Location, structure, and motion of Jupiter's dusk magnetospheric boundary from ∼1625 to 2550 RJ
Authors: Ebert R. W. , McComas D. J. , Bagenal F. , Elliott H. A.
Published: December 2010

We report on plasma observations along Jupiter's dusk magnetospheric flank from ∼1625 to 2550 RJ using measurements from the Solar Wind Around Pluto instrument onboard New Horizons (NH). NH observed 16 magnetopause crossings between 1654 and 2429 RJ that were identified by transitions between magnetotail/boundary layer and magnetosheath plasma. These transitions were either sharp, with the magnetopause clearly separating two distinct plasma regimes, or comparatively gradual, where it was difficult to distinguish between different plasma populations. The magnetosheath distributions had high counts, were relatively wide in energy/charge (E/Q), and steadily decreased in speed. Flow speeds in the sheath were always higher (lower) when NH entered (exited) this region. A boundary layer was observed inside of the magnetopause at several crossings. The boundary layer plasma was composed of light ions, and the counts and mean E/Q of these distributions were generally lower than magnetosheath values indicating a lower density and speed. Some of the NH magnetopause crossing locations fell within tail cross‐section estimates from model results/observations closer to the planet, though more than half were outside of the largest tail radius estimate. Estimates of angular displacement of the tail boundary compared favorably with a statistical study of near‐Jupiter solar wind flow cone angle distributions. We propose that the outward crossings resulted from dawnward deflection and contraction of the tail from forward shocks and compression regions in the near‐Jupiter solar wind, and the inward crossings resulted from duskward deflection and tail expansion from the passage of reverse shocks and rarefaction regions.
Temperature inversion in China seas
Authors: Hao Jiajia , Chen Yongli , Wang Fan
Published: December 2010

Temperature inversion was reported as a common phenomenon in the areas near the southeastern Chinese coast (region A), west and south of the Korean Peninsula (region B), and north and east of the Shandong Peninsula (region C) during October–May in the present study, based on hydrographic data archived from 1930 through 2001 (319,029 profiles). The inversion was found to be remarkable with obvious temporal and spatial variabilities in both magnitude and coverage, with higher probabilities in region A (up to about 60%) and region C (40%–50%) than in region B (15%–20%). The analysis shows that seasonal variation of the net air‐sea heat flux is closely related to the occurrence time of the inversion in the three areas, while the Yangtze and Yellow river freshwater plumes in the surface layer and ocean origin saline water in the subsurface layer maintain stable stratification. It seems that the evaporation/excessive precipitation flux makes little contribution to maintaining the stable inversion. Advection of surface fresh water by the wind‐driven coastal currents results in the expansion of inversion in regions A and C. The inversion lasts for the longest period in region A (October–May) sustained by the Taiwan Warm Current carrying the subsurface saline water, while evolution of the inversion in region B is mainly controlled by the Yellow Sea Warm Current.
Wintertime mesopause region vertical winds from Resolute Bay
Authors: Bhattacharya Yajnavalkya , Gerrard Andrew J.
Published: December 2010

Vertical neutral winds in the upper mesosphere‐lower thermosphere, measured by observing the hydroxyl (OH) airglow using a wide‐angle Michelson Interferometer from Resolute Bay (74°N), over the course of three Arctic winters, are presented. The measurement of vertical winds, which span 3 to 4 months during the 1995–1996, 1996–1997, and 2000–2001 winters, are unique and allow for a variety of studies on the mechanisms associated with vertical winds in the mesosphere; specifically the influences of both geomagnetic activity and the polar vortex. In this study it is observed that (1) these vertical wind measurements are consistent with other studies of vertical winds from high latitude sites using different instrumentation, (2) the amplitude of vertical winds are not sensitive to Ap index at the measurement location, and (3) the daily variance of vertical winds are moderately correlated to the position of the stratospheric polar vortex as revealed by diagnostics of stratospheric assimilated data at the 10 hPa level. These results should help enhance our understanding of the mechanisms that determine the magnitude and variability of vertical neutral winds at high latitudes.
Use of an improved radiation amplification factor to estimate the effect of total ozone changes on action spectrum weighted irradiances and an instrument response function
Authors: Herman Jay R.
Published: December 2010

Multiple scattering radiative transfer results are used to calculate action spectrum weighted irradiances and fractional irradiance changes in terms of a power law in ozone Ω, U(Ω/200)−RAF, where the new radiation amplification factor (RAF) is just a function of solar zenith angle. Including Rayleigh scattering caused small differences in the estimated 30 year changes in action spectrum‐weighted irradiances compared to estimates that neglect multiple scattering. The radiative transfer results are applied to several action spectra and to an instrument response function corresponding to the Solar Light 501 meter. The effect of changing ozone on two plant damage action spectra are shown for plants with high sensitivity to UVB (280–315 nm) and those with lower sensitivity, showing that the probability for plant damage for the latter has increased since 1979, especially at middle to high latitudes in the Southern Hemisphere. Similarly, there has been an increase in rates of erythemal skin damage and pre‐vitamin D3 production corresponding to measured ozone decreases. An example conversion function is derived to obtain erythemal irradiances and the UV index from measurements with the Solar Light 501 instrument response function. An analytic expressions is given to convert changes in erythemal irradiances to changes in CIE vitamin‐D action spectrum weighted irradiances.
Influences of Arctic Oscillation and Madden‐Julian Oscillation on cold surges and heavy snowfalls over Korea: A case study for the winter of 2009–2010
Authors: Park Tae‐Won , Ho Chang‐Hoi , Yang Song , Jeong Jee‐Hoon
Published: December 2010

In the winter of 2009–2010, frequent and long‐lasting cold weather affected Korea. Four major cold surges and several heavy snowfall events were observed, including a record‐breaking event on 4 January 2010. These four cold surges had distinct properties with regard to their relationships to the phases of the Arctic Oscillation (AO) and the Madden‐Julian Oscillation (MJO), suggesting the possible influences of the AO and MJO on the cold surges and heavy snowfalls. The four cold surges were of two distinct types: the wave train type and the blocking type, which were differentiated by their mechanisms. With regard to the relationships of the cold surges to the AO, three cold surges occurred during a strongly negative AO period, which lasted for more than 1 month. The Siberian High expanded from the Arctic high‐pressure region to East Asia during the negative AO period. A cold surge occurred during a positive AO, with the expansion of the Siberian High across the Eurasian continent. An MJO‐induced circulation, corresponding to strong tropical convection over the tropical Indian Ocean, seems to have reinforced the cold surges over East Asia. In addition, the active local Hadley circulation modulated by a convection center over the Indian Ocean tends to enhance midlatitude synoptic disturbances across East Asia and provides favorable conditions for upward motion over the region. In short, the effects of the AO and MJO, along with the existing low‐level moisture supply, contributed to heavy snowfalls associated with strong cold surges over Korea during the winter of 2009–2010.
Coupling groundwater and land surface processes: Idealized simulations to identify effects of terrain and subsurface heterogeneity on land surface energy fluxes
Authors: Rihani Jehan F. , Maxwell Reed M. , Chow Fotini K.
Published: December 2010

This work investigates the role of terrain and subsurface heterogeneity on the interactions between groundwater dynamics and land surface energy fluxes using idealized simulations. A three‐dimensional variably saturated groundwater code (ParFlow) coupled to a land surface model (Common Land Model) is used to account for both vertical and lateral water and pressure movement. This creates a fully integrated approach, coupling overland and subsurface flow while having an explicit representation of the water table and all land surface processes forced by atmospheric data. Because the water table is explicitly represented in these simulations, regions with stronger interaction between water table depth and the land surface energy balance (known as critical zones) can be identified. This study uses simple terrain and geologic configurations to demonstrate the importance of lateral surface and subsurface flows in determining land surface heat and moisture fluxes. Strong correlations are found between the land surface fluxes and water table depth across all cases, including terrain shape, subsurface heterogeneity, vegetation type, and climatological region. Results show that different land forms and subsurface heterogeneities produce very different water table dynamics and land surface flux responses to atmospheric forcing. Subsurface formation and properties have the greatest effect on the coupling between the water table and surface heat and moisture fluxes. Changes in landform and land surface slope also have an effect on these interactions by influencing the fraction of rainfall contributing to overland flow versus infiltration. This directly affects the extent of the critical zone with highest coupling strength along the hillside. Vegetative land cover, as seen in these simulations, has a large effect on the energy balance at the land surface but a small effect on streamflow and water table dynamics and thus a limited impact on the land surface‐subsurface interactions. Although climate forcing has a direct effect on water table dynamics and feedbacks to the land surface, in this study it does not overcome that of subsurface heterogeneity and terrain.
A joint velocity‐concentration PDF method for tracer flow in heterogeneous porous media
Authors: Meyer Daniel W. , Jenny Patrick , Tchelepi Hamdi A.
Published: December 2010

The probability density function (PDF) of the local concentration of a contaminant, or tracer, is an important component of risk assessment in applications that involve flow in heterogeneous subsurface formations. In this paper, a novel joint velocity‐concentration PDF method for tracer flow in highly heterogeneous porous media is introduced. The PDF formalism accounts for advective transport, pore‐scale dispersion (PSD), and molecular diffusion. Low‐order approximations (LOAs), which are usually obtained using a perturbation expansion, typically lead to Gaussian one‐point velocity PDFs. Moreover, LOAs provide reasonable approximations for small log conductivity variances (i.e., σY2 < 1). For large σY2, however, the one‐point velocity PDFs deviate significantly from the Gaussian distribution as demonstrated convincingly by several Monte Carlo (MC) simulation studies. Furthermore, the Lagrangian velocity statistics exhibit complex correlations that span a wide range of scales, including long‐range correlations due to the formation of preferential flow paths. Both non‐Gaussian PDFs and complex long‐range correlations are accurately represented using Markovian velocity processes (MVPs) in the proposed joint PDF method. LOA methods can be generalized to some extent by presuming a certain shape for the concentration PDF (e.g., a β PDF fully characterized by the concentration mean and variance). The joint velocity‐concentration PDF method proposed here does not require any closure assumptions on the shape of the marginal concentration PDF. The Eulerian joint PDF transport equation is solved numerically using a computationally efficient particle‐based approach. The PDF method is validated with high‐resolution MC reference data from Caroni and Fiorotto (2005) for saturated transport in velocity fields, which are stationary in space and time, for domains with σY2 = 0.05, 1, and 2 and Péclet numbers ranging from 100 to 10,000. PSD is modeled using constant anisotropic dispersion coefficients in both the reference MC computations and our PDF method.
High local substrate availability stabilizes a cooperative trait
Authors: Bachmann Herwig , Molenaar Douwe , Kleerebezem Michiel , van Hylckama Vlieg Johan E T
Published: December 2010

Cooperative behavior is widely spread in microbial populations. An example is the expression of an extracellular protease by the lactic acid bacterium Lactococcus lactis, which degrades milk proteins into free utilizable peptides that are essential to allow growth to high cell densities in milk. Cheating, protease-negative strains can invade the population and drive the protease-positive strain to extinction. By using multiple experimental approaches, as well as modeling population dynamics, we demonstrate that the persistence of the proteolytic trait is determined by the fraction of the generated peptides that can be captured by the cell before diffusing away from it. The mechanism described is likely to be relevant for the evolutionary stability of many extracellular substrate-degrading enzymes.
Body Image Changes Associated With Participation in an Intensive Lifestyle Weight Loss Intervention
Authors: Stewart Tiffany M. , Bachand Amy R. , Han Hongmei , Ryan Donna H. , Bray George A. , Williamson Donald A.
Published: December 2010

The primary aim of this study was to test for changes in body image in men and women enrolled in the Look AHEAD trial. Look AHEAD (Action for Health in Diabetes) is a multicenter, randomized controlled trial designed to test whether intentional weight loss reduces cardiovascular morbidity and mortality in overweight individuals with type 2 diabetes. Participants included 157 adults at one site (Pennington Biomedical Research Center (PBRC), Baton Rouge, LA) of the Look AHEAD study. At baseline, the mean BMI of the female participants was 36.4, and the mean BMI for males was 33.5. Following baseline assessment, participants were randomly assigned to the intensive lifestyle intervention (ILI, n = 81) or diabetes support and education (DSE, n = 76). The body morph assessment version 2.0 (BMA 2.0) was used to assess estimates of perceived current body size, ideal body size, acceptable body size, and body image dissatisfaction at baseline and 1 year. Over the 1 year, participants in the ILI group had significantly greater reductions in weight (10.1% for men and 8.9% for women) than those in the DSE group (+ 0.8% for men and −0.2%, for women). Perceived current body size was reduced significantly more in both men and women in the ILI group, relative to DSE. There were also significantly greater reductions in body image dissatisfaction in the ILI group, relative to the DSE group for men and women. The results of this study indicate that body image dissatisfaction improved following participation in an intensive behavioral weight loss program.
Éducation thérapeutique de l’enfant et de l’adolescent : réflexions éthiques en orthopédie dento-faciale
Authors: Mano Marie-Charlotte , Begué-Simon Anne-Marie , Hamel Olivier , Sorel Olivier , Hervé Christian
Published: December 2010

Les variations de l’observance, et plus encore, les situations d’abandon de traitement interpellent. D’un point de vue médical et économique, elles affectent l’efficience même des thérapeutiques. Ces situations d’échecs, thérapeutiques et relationnels, nous invitent à une réflexion sur la place et la mission des acteurs du soin, son sens et sa finalité. L’adhésion des patients est la clé de voûte du succès de nos thérapeutiques. Comment alors modifier les comportements de santé, en particulier chez l’adolescent ? Comment s’approprier et faire sienne la stratégie thérapeutique ? L’éducation thérapeutique du patient, récemment reconnue par le législateur et désormais inscrite au sein du code de la santé publique dans le champ des maladies chroniques, apporte de nouveaux éléments de réponse. L’objectif de ce travail est de questionner le concept d’éducation thérapeutique au regard de l’éthique médicale. En quoi ce concept interroge nos pratiques face aux défis de l’adhésion aux soins ? Quels sont les changements de perspectives et de postures soignantes induites par l’éducation thérapeutique ?
Le sourire dans la représentation et l’image de soi
Authors: Guth Élise , Bacon William
Published: December 2010

Le sourire joue-t-il un rôle dans l’acceptation de soi et le bien-être social du patient ? L’évaluation du sourire fait partie intégrante de l’examen clinique et participe au diagnostic. D’autres critères que les critères quantitatifs ou métriques classiquement utilisés sont abordés dans ce travail et en constituent l’originalité. Philosophie, psychologie et sociologie ont guidé notre recherche vers une compréhension du rôle du sourire dans les relations humaines et dans la représentation du soi. La quête dubeauest universelle, mais son jugement est entaché de subjectivité, même si certaines approches ont tenté d’objectiver le beau et de le mettre en équation. L’acceptation de l’image du corps est fondamentale pour le bien-être psychique et social de l’individu. L’aphorisme de Montaigne « mieux vaut une tête bien faite ... » tient toujours. L’Homme enfin ne peut pas négliger de se soumettre aux règles et coutumes de ses « semblables » s’il veut s’intégrer harmonieusement à la société qui l’entoure. Même si certains standards esthétiques sont incontournables et semblent universels, cette réalité « naturelle » de la beauté est pervertie par les diktats des règles sociales dans la quotidienneté de chacun; principe qui s’applique à la représentation du sourire. Commencer par écouter son patient avant de regarder ses dents.
The coupled vibration of fluid-filled multiwalled carbon nanotubes with intertube deformation
Authors: Wang X. Y. , Chen W.
Published: December 2010

Carbon nanotubes hold substantial and exciting promise as nanocontainers filled with fluid or nanopipes conveying fluid in their hollow cavity in nanotechnology. This paper studies the coupled vibration of embedded fluid-filled multiwalled carbon nanotubes (MWNTs) subject to axial load using the multiple-Euler beam model and considering the distinctive intertube deformation of carbon MWNTs. Through the numerical examples, the effective scope of the single-beam model is examined, and the effect of the internal fluid on the coupled vibration for various geometric dimensions, mass densities of the fluid, Winkler constants, axial loads, and mode numbers, is investigated. It is found that the influence of fluid coupling effect on the natural vibrating frequencies of fluid-filled MWNTs increases as the density of the fluid increases, or as the diameter of the innermost tube increases, or as the mode number studied decreases, and, the higher mode number n or density of the fluid ρf is, the more intense the vibration of inner tubes are than that of outer tubes, and the more the vibration tends towards noncoaxial.
An alternative flat scanner and micropositioning method for scanning probe microscope
Authors: Cai Wei , Shang Guangyi , Zhou Yusheng , Xu Ping , Yao Junen
Published: December 2010

An alternative flat scanner used for combining a scanning probe microscope with an inverted optical microscope is presented. The scanner has a novel structure basically consisting of eight identical piezoelectric tubes, metal flexure beams, and one sample mount. Because of the specially designed structure, the scanner is able to carry a sample of more than 120 g during imaging. By applying voltages of ±150 V, scanning range of more than 30 μm in three dimensions can be achieved. To improve the reliability of the stick-slip motion, a new method for sample micropositioning is proposed by applying a pulsed voltage to the piezotubes to produce a motion in the z-axis. Reliable translation of the sample has been thus accomplished with the step length from ∼700 nm to 9 μm over a range of several millimeters. A homemade scanning probe microscope–inverted optical microscope system based on the scanner is described. Experimental results obtained with the system are shown.
Electrical characterization of HgTe nanowires using conductive atomic force microscopy
Authors: Gundersen P. , Kongshaug K. O. , Selvig E. , Haakenaasen R.
Published: December 2010

Self-organized HgTe nanowires grown by molecular beam epitaxy (MBE) have been characterized using conductive atomic force microscopy. As HgTe will degrade or evaporate at normal baking temperatures for electron beam lithography (EBL) resists, an alternative method was developed. Using low temperature optical lithography processes, large Au contacts were deposited on a sample covered with randomly oriented, lateral HgTe nanowires. Nanowires partly covered by the large electrodes were identified with a scanning electron microscope and then localized in the atomic force microscope (AFM). The conductive tip of the AFM was then used as a movable electrode to measure current-voltage curves at several locations on HgTe nanowires. The measurements revealed that polycrystalline nanowires had diffusive electron transport, with resistivities two orders of magnitude larger than that of an MBE-grown HgTe film. The difference can be explained by scattering at the rough surface walls and at the grain boundaries in the wires. The method can be a solution when EBL is not available or requires too high temperature, or when measurements at several positions along a wire are required.
Strong pinning in thick YBa2Cu3O7 layers mediated by catalysis of a new long-period metastable cuprate phase
Authors: Solovyov Vyacheslav F. , Develos-Bagarinao Katherine , Li Qiang , Si Wei-Dong , Wu Li-Jun , Zhou Juan , Wiesmann Harold , Qing Jie
Published: December 2010

Catalysts are widely utilized to promote reactions in liquid and gaseous phases but are rarely encountered in solid state synthesis. Here we use catalytically active (001) ceria buffers to modify the structure of the epitaxial high temperature superconductor YBa2Cu3O7. The modification is achieved by catalytically-assisted synthesis of a previously unknown metastable phase. The new phase, a long-period (3.5 nm) perovskite, intercalates into the YBa2Cu3O7 matrix without negatively affecting the critical temperature of the film. Analysis of electron microscopy and synchrotron x-ray diffraction data allow identification of the phase as a long-period YBa2Cu3O7 derivative formed through short-range cation displacement. The 0.8 μm thick films exhibit strong enhancement of the critical current density, reaching a maximum of 4.2 MA/cm2 at 77 K. The result emphasizes the critical role of catalysis for synthesis of novel complex materials.
On temperature-dependent experimental I-V and C-V data of Ni/n-GaN Schottky contacts
Authors: Yıldırım Nezir , Ejderha Kadir , Turut Abdulmecit
Published: December 2010

We report the current-voltage (I-V) and capacitance-voltage characteristics (C-V) of Ni/n-GaN Schottky diodes. Gallium nitride is a highly promising wide band gap semiconductor for applications in high power electronic and optoelectronic devices which require Schottky barriers for modulating the channel mobile charge. The I-V and C-V characteristics of the diodes have been measured in the temperature range of 80–400 K with steps of 20 K. Thermal carrier concentration and barrier height versus temperature plots have been obtained from the C−2-V characteristics, and a value of α=−1.40 meV/K for temperature coefficient of the barrier height. The modified activation energy plot according to the barrier inhomogeneity model has given the Richardson constant A∗ as 80 or 85 A/(cm2 K2).
Equation of state and liquid-vapor equilibrium of polarizable Stockmayer fluids
Authors: Rocha-Ichante Adrián , del Río Fernando , Ávalos Edgar
Published: December 2010

In this work we develop the concept of an effective potential to obtain the equation of state of polarizable Stockmayer (PSM) fluids. This potential consists of a Lennard-Jones function with appropriate energy and distance parameters that depend on the reduced dipolar moment \documentclass[12pt]{minimal}\begin{document}$\mu ^\ast$\end{document}μ* and polarizability \documentclass[12pt]{minimal}\begin{document}$\alpha ^\ast$\end{document}α*. The approach deals accurately with polarizable SM fluids with \documentclass[12pt]{minimal}\begin{document}$\mu ^{\ast } \le 2.0$\end{document}μ*≤2.0 and \documentclass[12pt]{minimal}\begin{document}$\alpha ^{\ast } \le 0.1$\end{document}α*≤0.1. However, prediction of second virial coefficients is reliable up to \documentclass[12pt]{minimal}\begin{document}$\mu ^{\ast } \le 4.0$\end{document}μ*≤4.0. When the low-density sphericalized potential is used at moderate and large densities, the effect of the dipole–dipole attraction is overestimated in agreement with an effect previously found in the literature. This effect can be traced back to a frustration mechanism due to the interaction between three and more dipoles. We propose a model to account for this frustration effect and are able to reproduce the vapor-liquid equilibrium of polarizable SM fluids in agreement with simulated results from the literature. Molecular dynamics simulations were carried out to show that the effective SM fluid has a radial distribution function very close to that of the true SM system.
Evaluation of active flow control applied to wind turbine blade section
Authors: Stalnov O. , Kribus A. , Seifert A.
Published: December 2010

A feasibility study for implementing active flow control (AFC) methods to improve the performance of wind turbines was performed. The experimental effort investigated the impact of zero-mass-flux (ZMF) piezofluidic actuators attempting to control boundary layer separation from thick airfoils that are suitable for wind turbine rotor blades. It was demonstrated that the ZMF actuators can replace passive vortex generators that are commonly used for boundary layer separation delay, without the inherent drag penalty that the passive devices impose. It has been shown that ZMF fluidic actuators are suitable for flow control in wind turbine application due to the fact that they are adjustable for wider Reynolds number range, while vortex generators are tuned to perform well in one design point. It was demonstrated that AFC can effectively double the maximum lift of this airfoil at low Reynolds numbers. A possible application is a significant reduction of the turbine start-up velocity. It was also found that even for a contaminated blade, AFC is capable to delay the stall and decrease the drag using low energy expenditure, therefore restoring and even surpassing the clean airfoil performance. The effectiveness of the AFC method was examined using a newly defined aerodynamic figure of merit. Various scaling options for collapsing the effect of the excitation magnitude on the lift alternation due to the activation of zero-mass-flux periodic excitation for boundary layer separation control are proposed and examined using experimental data.
Nanoelectronic detection of breast cancer biomarker
Authors: Chen Yu , Wang Xihua , Hong Mi K. , Rosenberg Carol L. , Reinhard Björn M. , Erramilli Shyamsunder , Mohanty Pritiraj
Published: December 2010

There is a fundamental need for semiconductor-based ultrasensitive nanosensors for detecting heterogeneous biomarkers associated with cancer, which do not have a well-defined molecular weight. Here we show that a nanoscale gated biological field effect transistor can be used for detecting the breast cancer serum biomarker protein CA15.3 down to levels of concentration less than 20 units/ml, relevant for clinical use. Our work extends the capability of nanowire sensors to a class of mucin-based heterogeneous protein biomarkers that are of fundamental importance to modern cancer detection.
Identifying complex periodic windows in continuous-time dynamical systems using recurrence-based methods
Authors: Zou Yong , Donner Reik V. , Donges Jonathan F. , Marwan Norbert , Kurths Jürgen
Published: December 2010

The identification of complex periodic windows in the two-dimensional parameter space of certain dynamical systems has recently attracted considerable interest. While for discrete systems, a discrimination between periodic and chaotic windows can be easily made based on the maximum Lyapunov exponent of the system, this remains a challenging task for continuous systems, especially if only short time series are available (e.g., in case of experimental data). In this work, we demonstrate that nonlinear measures based on recurrence plots obtained from such trajectories provide a practicable alternative for numerically detecting shrimps. Traditional diagonal line-based measures of recurrence quantification analysis as well as measures from complex network theory are shown to allow an excellent classification of periodic and chaotic behavior in parameter space. Using the well-studied Rössler system as a benchmark example, we find that the average path length and the clustering coefficient of the resulting recurrence networks are particularly powerful discriminatory statistics for the identification of complex periodic windows.
Breakup of diminutive Rayleigh jets
Authors: van Hoeve Wim , Gekle Stephan , Snoeijer Jacco H. , Versluis Michel , Brenner Michael P. , Lohse Detlef
Published: December 2010

Discharging a liquid from a nozzle at sufficient large velocity leads to a continuous jet that due to capillary forces breaks up into droplets. Here we investigate the formation of microdroplets from the breakup of micron-sized jets with ultra high-speed imaging. The diminutive size of the jet implies a fast breakup time scale τc=ρr3/γ of the order of 100 ns, and requires imaging at 14×106 frames/s. We directly compare these experiments with a numerical lubrication approximation model that incorporates inertia, surface tension, and viscosity [J. Eggers and T. F. Dupont, J. Fluid Mech. 262, 205 (1994); X. D. Shi, M. P. Brenner, and S. R. Nagel, Science 265, 219 (1994)]. The lubrication model allows to efficiently explore the parameter space to investigate the effect of jet velocity and liquid viscosity on the formation of satellite droplets. In the phase diagram, we identify regions where the formation of satellite droplets is suppressed. We compare the shape of the droplet at pinch-off between the lubrication approximation model and a boundary-integral calculation, showing deviations at the final moment of the pinch-off. In spite of this discrepancy, the results on pinch-off times and droplet and satellite droplet velocity obtained from the lubrication approximation agree with the high-speed imaging results.
Resonant coupling in dielectric loaded plasmonic waveguides
Authors: Krishnan A. , Regan C. J. , Grave de Peralta L. , Bernussi A. A.
Published: December 2010

Light propagation in dielectric loaded surface plasmon polariton waveguide (DLSPPW) resonant coupling devices operating at visible frequencies was experimentally investigated. The transmission characteristics of these devices were studied by leakage radiation microscopy. We show that a strong coupling between DLSPPWs can be achieved with nanoscale gaps. We demonstrate the operation of compact DLSPPW linear couplers and 3 dB power splitters. The performances of micro-DLSPPW racetrack resonators and signal drop filter are also discussed.
Inferring social ties from geographic coincidences
Authors: Crandall David J. , Backstrom Lars , Cosley Dan , Suri Siddharth , Huttenlocher Daniel , Kleinberg Jon
Published: December 2010

We investigate the extent to which social ties between people can be inferred from co-occurrence in time and space: Given that two people have been in approximately the same geographic locale at approximately the same time, on multiple occasions, how likely are they to know each other? Furthermore, how does this likelihood depend on the spatial and temporal proximity of the co-occurrences? Such issues arise in data originating in both online and offline domains as well as settings that capture interfaces between online and offline behavior. Here we develop a framework for quantifying the answers to such questions, and we apply this framework to publicly available data from a social media site, finding that even a very small number of co-occurrences can result in a high empirical likelihood of a social tie. We then present probabilistic models showing how such large probabilities can arise from a natural model of proximity and co-occurrence in the presence of social ties. In addition to providing a method for establishing some of the first quantifiable estimates of these measures, our findings have potential privacy implications, particularly for the ways in which social structures can be inferred from public online records that capture individuals’ physical locations over time.
Rad52 inactivation is synthetically lethal with BRCA2 deficiency
Authors: Feng Zhihui , Scott Shaun P. , Bussen Wendy , Sharma Girdhar G. , Guo Gongshe , Pandita Tej K. , Powell Simon N.
Published: December 2010

Synthetic lethality is a powerful approach to study selective cell killing based on genotype. We show that loss of Rad52 function is synthetically lethal with breast cancer 2, early onset (BRCA2) deficiency, whereas there was no impact on cell growth and viability in BRCA2-complemented cells. The frequency of both spontaneous and double-strand break-induced homologous recombination and ionizing radiation-induced Rad51 foci decreased by 2–10 times when Rad52 was depleted in BRCA2-deficient cells, with little to no effect in BRCA2-complemented cells. The absence of both Rad52 and BRCA2 resulted in extensive chromosome aberrations, especially chromatid-type aberrations. Ionizing radiation-induced and S phase-associated Rad52-Rad51 foci form equally well in the presence or absence of BRCA2, indicating that Rad52 can respond to DNA double-strand breaks and replication stalling independently of BRCA2. Rad52 thus is an independent and alternative repair pathway of homologous recombination and a target for therapy in BRCA2-deficient cells.
Human aspects of siltation of Lake Baringo: Causes, impacts and interventions
Authors: Lwenya Carolyne , Yongo Ernest
Published: December 2010

Lake Baringo is one of the important fresh water lakes in the Kenyan Rift Valley that is primarily arid in nature. It is an important world Ramsar site and also important in terms of socio-economic diversity and biodiversity. Despite this, the lake is threatened by siltation resulting from human activities in its catchment. A study was carried out to identify the factors contributing to siltation and to suggest strategies and opportunities to mitigate the problem. Quantitative methods were used to collect data. Results indicated that the livelihoods of communities around Lake Baringo depend on livestock rearing, charcoal burning and cultivation. Poor land-use systems together with resource user conflicts, political marginalization, poverty, weak institutions and policies are factors contributing to land and water degradation. Negative impacts of siltation identified include destruction, of fish breeding areas, flooding, poor water quality affecting human and animal use and increased resource user conflicts. Strategies that various institutions are undertaking such as replanting indigenous vegetation, are showing little progress due to lack of co-ordination, the nature of the landscape, the lack of funding and political will. This paper has identified opportunities for soil management systems such as use of indigenous trees and grasses to enhance livelihoods for local communities, while at the same time conserving the soils.
Comparison of the genetic and ecological diversity of the native to the introduced tilapiines (Pisces: Cichlidae), and their population structures in the Lake Victoria region, East Africa
Authors: Mwanja Wilson Waiswa , Kaufman Les , Fuerst Paul A.
Published: December 2010

The impact of introduced tilapiines in Lake Victoria Region (LVR) was studied using experimental fishing survey methods and microsatellite DNA marker analysis. The experiments were carried out between 1993 and 2000. Oreochromis esculentus and O. variabilis, the two native forms of the LVR and original principals of the fisheries of these waters, were found to be completely displaced from the major lakes and were only occasionally found in a few minor satellite lakes surrounding Lakes Kyoga and Victoria. Nile tilapia, O. niloticus, is now the dominant tilapiine, and one of the three key fisheries species of LVR along with Nile perch, Lates niloticus, and the minnow-like Rastrineobola argentea. Oreochromis leucostictus, also introduced to the LVR from the nilotic system, was largely restricted to swampy fringes of LVR water bodies. Tilapia zillii, also introduced from nilotic waters and earlier recorded to have been the most prevalent introduced tilapiine in LVR, occurred only sparsely and was very restricted in distribution. Genetic studies showed Nile tilapia having the highest genetic diversity, and being the least subdivided among LVR tilapiines. O. leucostictus was next in variability, but had the greatest gene flow, probably due to its ability to traverse low oxygen waters such as swamps which separate most LVR water bodies. The native forms were genetically the least variable, except where they coexist with introduced congeners. ‘Uncontaminated’ native forms were observed only in satellite Lakes of Kayanja, Kayugi, Manywa, Kawi and Kanyaboli. The population structure of native forms of LVR suggest they are being genetically swamped, especially for O. variabilis by Nile tilapia alleles, due to genetic exchange with introduced forms, resulting in highly localized differentiation of native species. T. zillii was equally highly subdivided, but has higher genetic variation within subpopulations, a situation linked to monogamous breeding behaviour which allows most individuals of its population to participate in breeding. Hybridization with T. rendalli, which was only occasionally encountered and previously mistaken for dwarf Nile tilapia, may also contribute to high within population variation in small T. zillii populations. On a macro-evolutionary level, the sister relationship between O. niloticus and O. esculentus is questionable and in need of further phylogenetic analysis. Overall the study showed a changed fishery, and the need to manage satellite lakes in a manner that will preserve the previous premier elements of the region's fishery (O. esculentus and O. variabilis) within natural refugia.
Food chains of Ganga River ecosystems in the Himalayas
Authors: Nautiyal Prakash
Published: December 2010

The river ecosystems from the headwaters to the foothills in the upper mountain reach of the Ganga (Bhagirathi River) were characterized by increasing temperature, pH, total alkalinity, nutrient and BOD and decreasing current velocity, turbidity and DO. The biotic communities included benthos (phytobenthos, zoobenthos) and nekton (fish). The headwaters at Gangotri were heterotrophic and lacked fish (both grazers and predators). Functionally, the detritus and grazing chains operate in headwaters of the upper Ganga. The food chain was short and the web simple. In the middle and lower stretches, the macroinvertebrate assemblages functioned as filtering collectors and scrapers, representing detritus and grazing food chains. The abundance of scrapers indicated transition from heterotrophic to autotrophic state. The food chains and the food web became complex from the middle to lower stretches.
Checking the pulse of Lake Ontario's microbial-planktonic communities: A trophic transfer hypothesis
Authors: Munawar M. , Fitzpatrick M. , Munawar I. F. , Niblock H.
Published: December 2010

The structure and function of the microbial food web of Lake Ontario was assessed at 15 stations distributed across 4 transects during the spring and summer of 2003. This was the first major binational study of Lake Ontario since the Lake Ontario Trophic Transfer initiative of 1990. The microbial loop (bacteria, autotrophic picoplankton, heterotrophic nanoflagellates (HNF) and ciliates) and phytoplankton, were enumerated microscopically in addition to measurements of chlorophyll a, size fractionated primary productivity (14C) and bacterial growth (3H). HNF dominated the total biomass in spring (≈300 mg m−3) and summer (≈1250 mg m−3). The size of the organic carbon pool increased from ≈90 mg C m−3 in spring to ≈270 mg C m−3 with HNF contributing 36% of the total organic carbon in the spring and 52% in the summer; however the net balance of the organic carbon pool shifted from autotrophic in the spring to heterotrophic in the summer. The available evidence suggests that HNF are a poor quality food resource for zooplankton and it is likely that the carbon sequestered by HNF is not available to higher trophic levels resulting in dietary stress for planktivores. The implications of high HNF for both organic carbon cycling and maintaining healthy fisheries needs further research. Independent observations show that oligotrophic conditions prevail as evidenced by low phosphorus, low chlorophyll a, low plankton and high water clarity. Such conditions have been generally regarded as the gold standard for managing healthy lakes. Lake Ontario is oligotrophic and healthy from a water quality perspective, but from a food web dynamics point of view, Lake Ontario appears to be unhealthy due to the dominance of HNF, low zooplankton and poor quality of food available to higher trophic levels. We hypothesize that the lake's poor health is attributable to inefficient energy transfer from lower to higher trophic levels. The traditional understanding of trophic state based mainly on water quality criteria needs to be broadened by the inclusion of food web and fisheries based metrics.
Investigating the Validity of the Classification of Violence Risk in a UK Sample
Authors: Doyle Michael , Shaw Jenny , Carter Stuart , Dolan Mairead
Published: December 2010

We attempted to cross-validate the Classification of Violence Risk, or COVR ( Monahan, Steadman, Appelbaum et al., 2005 ), in a sample of acute psychiatric patients in the North West of England. The study used a prospective design to follow-up 93 patients assessed using the COVR for 20 weeks post-discharge. Overall, the COVR did not demonstrate significant predictive validity with respect to violence. More than half of patients classified as average risk by the COVR were violent in the follow-up compared to less than 20% of those in the very low risk group, but none of the high-risk participants were violent. In contrast, violence was significantly predicted by key variables, including female gender, violence preceding admission, and personality disorder. There is a need for more cross-validation research of the COVR.
The Development of a UK Low Secure Service: Philosophy, Training, Supervision and Evaluation
Authors: Davies Jason , Maggs RichardG. , Lewis Roger
Published: December 2010

Within the UK, low secure mental health services provide care and treatment to individuals with a view to supporting their return to life within community settings. With the expansion of services in this area it is essential that effective models of care are articulated, delivered and evaluated. This paper describes the philosophical underpinnings of the Intensive Support and Intervention Service, a new low secure inpatient facility. The operationalization of the approach to recovery is described along with the role and impact of the initial staff training. Clinical supervision as a critical component to ongoing practice delivery and development is described. Finally, the methods being utilized to evaluate the service are outlined.
Predictive Validity and Other Psychometric Properties of the Short-Term Assessment of Risk and Treatability (START) in a Norwegian High Secure Hospital
Authors: Nonstad Kåre , Nesset MereteB. , Kroppan Erik , Pedersen TrulsW. , Nøttestad JimAa. , Almvik Roger , Palmstierna Tom
Published: December 2010

Short- to medium-term risk assessment in psychiatric hospitals is a topic of clinical relevance that deserves attention from the research community. In this paper, the Short Term Assessment of Risk and Treatability, or START ( Webster, Martin, Brink, Nicholls, & Middleton, 2004 ), a new structured instrument for judgment of dynamic risk and treatment factors is briefly described. Internal reliability properties are analyzed and the predictive validity for severe violence in a Norwegian high secure psychiatric hospital is investigated. The results indicate that the START has promise as a valid tool for short-term violence risk assessment. The authors make an argument for the importance and relevance of dynamic risk and strength factors in the short to medium term.
Low temperature atmospheric pressure plasma sources for microbial decontamination
Authors: Ehlbeck J , Schnabel U , Polak M , Winter J , von Woedtke Th , Brandenburg R , von dem Hagen T , Weltmann K-D
Published: December 2010

The aim of this paper is to provide a survey of plasma sources at atmospheric pressure used for microbicidal treatment. In order to consider the interdisciplinary character of this topic an introduction and definition of basic terms and procedures are given for plasma as well as for microbicidal issues. The list of plasma sources makes no claim to be complete, but to represent the main principles of plasma generation at atmospheric pressure and to give an example of their microbicidal efficiency. The interpretation of the microbicidal results remain difficult due to the non-standardized methods used by different authors and due to the fact that small variations in the setup can change the results dramatically.
Space-charge dynamic in polyethylene: from dc to ac stress
Authors: Thomas C , Teyssedre G , Laurent C
Published: December 2010

Time-resolved space-charge profiles obtained in low-density polyethylene under sinusoidal or square ac stress for frequencies going from dc to 10 Hz, temperature from 25 to 50 °C and fields of 30 or 40 kV mm−1 are presented. It is shown that most of the features observed under dc stress (generation of carriers of the two polarities with non-symmetrical amount and velocity) are still active under ac stress. As a matter of fact, it is shown that a negative space charge builds up at 50 °C within the whole insulation bulk even with relatively high stress frequency and for short stressing time (2 h). These results clearly show that space charge has to be considered under ac condition.
Compressive dynamic scission of carbon nanotubes under sonication: fracture by atomic ejection
Authors: Chew H. B. , Moon M.-W. , Lee K. R. , Kim K.-S.
Published: December 2010

We report that a graphene sheet has an unusual mode of atomic-scale fracture owing to its structural peculiarity, i.e. single sheet of atoms. Unlike conventional bond-breaking tensile fracture, a graphene sheet can be cut by in-plane compression, which is able to eject a row of atoms out-of-plane. Our scale-bridging molecular dynamics simulations and experiments reveal that this compressive atomic-sheet fracture is the critical precursor mechanism of cutting single-walled carbon nanotubes (SWCNTs) by sonication. The atomic-sheet fracture typically occurs within 200 fs during the dynamic axial buckling of a SWCNT; the nanotube is loaded by local nanoscale flow drag of water molecules caused by the collapse of a microbubble during sonication. This is on the contrary to common speculations that the nanotubes would be cut in tension, or by high-temperature chemical reactions in ultrasonication processes. The compressive fracture mechanism clarifies previously unexplainable diameter-dependent cutting of the SWCNTs under sonication.