bluuebunny/crossref_metadata_2025 huggingface dataset:
A formal approach to collaborative modelling and co-simulation for embedded systems
Authors: FITZGERALD J. S. , LARSEN P. G. , PIERCE K. G. , VERHOEF M. H. G.
Published: July 2013

The effective use of model-based formal methods in the development of complex embedded systems requires the integration of discrete-event models of controllers with continuous-time models of their environments. This paper proposes a new approach to the development of such combined models (co-models), in which an initial discrete-event model may include approximations of continuous-time behaviour that can subsequently be replaced by couplings to continuous-time models. An operational semantics of co-simulation allows the discrete and continuous models to run on their respective simulators and managed by a coordinating co-simulation engine. This permits the exploration of the composite co-model's behaviour in a range of operational scenarios. The approach has been realised using the Vienna Development Method (VDM) as the discrete-event formalism, and 20-sim as the continuous-time framework, and has been applied successfully to a case study based on the distributed controller for a personal transporter device.
Model checking for performability
Authors: BAIER C. , HAHN E. M. , HAVERKORT B. R. , HERMANNS H. , KATOEN J.-P.
Published: July 2013

This paper gives a bird's-eye view of the various ingredients that make up a modern, model-checking-based approach to performability evaluation: Markov reward models, temporal logics and continuous stochastic logic, model-checking algorithms, bisimulation and the handling of non-determinism. A short historical account as well as a large case study complete this picture. In this way, we show convincingly that the smart combination of performability evaluation with stochastic model-checking techniques, developed over the last decade, provides a powerful and unified method of performability evaluation, thereby combining the advantages of earlier approaches.
Dante's Theology
Authors: Schaff Philip
Published: July 2013

The Divina Commedia, that “sacred poem”—

“To which both heaven and earth have set their hand,”

has an equal attraction for the poet, the historian, the philosopher, and the theologian. It is a mirror of mediaeval Christianity and civilization, and resembles a Gothic cathedral which lays all sciences and arts under contribution and fills the mind with wonder and awe. It has justly been called “the mediaeval miracle of song.” No poem can be compared with it for general and abiding interest except the Book of Job, and Goethe's Faust.
Reduced subcortical glutamate/glutamine in adults with autism spectrum disorders: a [1H]MRS study
Authors: Horder J , Lavender T , Mendez M A , O'Gorman R , Daly E , Craig M C , Lythgoe D J , Barker G J , Murphy D G
Published: July 2013

Dysfunctional glutamatergic neurotransmission has been implicated in autism spectrum disorder (ASD). However, relatively few studies have directly measured brain glutamate in ASD adults, or related variation in glutamate to clinical phenotype. We therefore set out to investigate brain glutamate levels in adults with an ASD, comparing these to healthy controls and also comparing results between individuals at different points on the spectrum of symptom severity. We recruited 28 adults with ASD and 14 matched healthy controls. Of those with ASD, 15 fulfilled the ‘narrowly’ defined criteria for typical autism, whereas 13 met the ‘broader phenotype’. We measured the concentration of the combined glutamate and glutamine signal (Glx), and other important metabolites, using proton magnetic resonance spectroscopy in two brain regions implicated in ASD—the basal ganglia (including the head of caudate and the anterior putamen) and the dorsolateral prefrontal cortex—as well as in a parietal cortex ‘control’ region. Individuals with ASD had a significant decrease (P<0.001) in concentration of Glx in the basal ganglia, and this was true in both the ‘narrow’ and ‘broader’ phenotype. Also, within the ASD sample, reduced basal ganglia Glx was significantly correlated with increased impairment in social communication (P=0.013). In addition, there was a significant reduction in the concentration of other metabolites such as choline, creatine (Cr) and N-acetylaspartate (NAA) in the basal ganglia. In the dorsolateral prefrontal cortex, Cr and NAA were reduced (P<0.05), although Glx was not. There were no detectable differences in Glx, or any other metabolite, in the parietal lobe control region. There were no significant between-group differences in age, gender, IQ, voxel composition or data quality. In conclusion, individuals across the spectrum of ASD have regionally specific abnormalities in subcortical glutamatergic neurotransmission that are associated with variation in social development.
Endothelial dysfunction in hyperandrogenic polycystic ovary syndrome is not explained by either obesity or ectopic fat deposition
Authors: Sprung Victoria S. , Jones Helen , Pugh Christopher J. A. , Aziz Nabil F. , Daousi Christina , Kemp Graham J. , Green Daniel J. , Cable N. Timothy , Cuthbertson Daniel J.
Published: July 2013

PCOS (polycystic ovary syndrome) is associated with IR (insulin resistance), increased visceral fat and NAFLD (non-alcoholic fatty liver disease) all of which may contribute to endothelial dysfunction, an early marker of CVD (cardiovascular disease) risk. Our objective was to examine the relationships between endothelial dysfunction in PCOS, the volume of AT (adipose tissue) compartments and the size of intracellular TAG (triacylglycerol) pools in liver and skeletal muscle. A total of 19 women with PCOS (means±S.D.; 26±6 years, 36±5 kg/m2) and 16 control women (31±8 years, 30±6 kg/m2) were recruited. Endothelial function was assessed in the brachial artery using FMD (flow-mediated dilation). VAT (visceral AT) and abdominal SAT (subcutaneous AT) volume were determined by whole body MRI, and liver and skeletal muscle TAG by 1H-MRS (proton magnetic resonance spectroscopy). Cardiorespiratory fitness and HOMA-IR (homoeostasis model assessment of IR) were also determined. Differences between groups were analysed using independent Student's t tests and ANCOVA (analysis of co-variance). FMD was impaired in PCOS by 4.6% [95% CI (confidence interval), 3.0–7.7; P<0.001], and this difference decreased only slightly to 4.2% (95% CI, 2.4–6.1; P<0.001) when FMD was adjusted for individual differences in visceral and SAT and HOMA-IR. This magnitude of impairment was also similar in lean and obese PCOS women. The results suggest that endothelial dysfunction in PCOS is not explained by body fat distribution or volume. FMD might be a useful independent prognostic tool to assess CVD risk in this population.
On the relaxation dynamics of the Kuramoto oscillators with small inertia
Authors: Choi Young-Pil , Ha Seung-Yeal , Noh Se Eun
Published: July 2013

For the Kuramoto oscillators with small inertia, we present several quantitative estimates on the relaxation dynamics and formational structure of a phase-locked state (PLS) for some classes of initial configurations. In a super-critical regime where the coupling strength is strictly larger than the diameter of natural frequencies, we present quantitative relaxation dynamics on the collision numbers and the structure of PLS. In a critical coupling regime where the coupling strength is exactly the diameter of natural frequencies, we provide a sufficient condition for an asymptotically PLS solution. In particular, we show the existence of slow relaxation to a PLS, when there are exactly two natural frequencies. This generalizes the earlier results of Choi et al. [“Asymptotic formation and orbital stability of phase locked states for the Kuramoto model,” Physica D 241, 735–754 (2012)10.1016/j.physd.2011.11.011; Choi et al. “Complete synchronization of Kuramoto oscillators with finite inertia,” Physica D 240, 32–44 (2011)]10.1016/j.physd.2010.08.004
Molecular modeling of the liquid-vapor interfaces of a multi-component mixture: Prediction of the coexisting densities and surface tensions at different pressures and gas compositions
Authors: Neyt J. C. , Wender A. , Lachet V. , Ghoufi A. , Malfreyt P.
Published: July 2013

Two-phase molecular simulations are performed in order to report the interfacial tensions and the coexisting densities of a multicomponent mixture (nitrogen + methane) + water for five gas compositions in the pressure range of 1–30 MPa at 298 K. The interfacial tensions are calculated using different definitions and the long range corrections of the surface tensions are considered using expressions designed for multicomponent mixtures and each definitions. We can conclude that the agreement with experiments is quantitative with deviations smaller than 5% for the interfacial tensions and 2% for the densities. The interfacial region is described in terms of specific arrangements of the gas components at the water surface.
Efficient dye-sensitized solar cells based on cosensitized metal free organic dyes with complementary absorption spectra
Authors: Sharma G. D. , Prakash Singh Surya , Nagarjuna P. , Mikroyannidis J. A. , Ball R. J. , Kurchania Rajnish
Published: July 2013

Dye sensitized solar cells (DSSCs) were fabricated using two metal-free organic dyes, TA-St-CA and D, with complementary absorption bands in the visible and near infrared regions. The power conversion efficiency (PCE) of the cosensitized DSSC (6.26%) was improved when compared to DSSCs based on individual dyes TA-St-CA (4.98%) or D (4.22%). The PCE was further enhanced up to 7.19% when deoxycholic acid (DCA) was added to the mixed dye solution as a coadsorbant. The enhancement of PCE observed in the cosensitized DSSC by addition of DCA was attributed to both suppression of dye aggregation and prevention of the backward electron transfer from the conduction band of TiO2.
Double asymptotic expansion of three-center electronic repulsion integrals
Authors: Alvarez-Ibarra A. , Köster A. M.
Published: July 2013

A double asymptotic expansion for the evaluation of three-center electron repulsion integrals (ERIs) in the long-range limit is presented. For the definition of this limit, a natural division of space based on the atomic coordinates and basis function exponents in utilized. The resulting analytical expression for the calculation of three-center ERIs in the long-range limit are implemented in the density functional theory program deMon2k. Validation and benchmark calculations of n-alkanes, hydrogen saturated graphene sheets and hydrogen saturated diamond blocks are discussed. It is shown that for a sufficient large number of long-range ERIs, the linear scaling regime is reached.
Fast and reliable fabrication of gold tips with sub-50 nm radius of curvature for tip-enhanced Raman spectroscopy
Authors: Lopes Manuel , Toury Timothée , de La Chapelle Marc Lamy , Bonaccorso Francesco , Giuseppe Gucciardi Pietro
Published: July 2013

We have developed a new electrochemical etching procedure to fabricate gold tips with sub-50 nm apical radius of curvature with a production yield of 80% and production time lower than 5 min. The technique is based on a two-step self-terminating process in which a gold wire is first quickly (<1 min) pre-etched in an hydrochloric acid (HCl)/ethanol solution at high voltage (10 VDC), and then slowly (2–4 min) etched at lower voltages (<2.5 VDC). The first step occurs under intense bubbling conditions and allows us to thin rapidly the wire. This reduces the time required by subsequent low-voltage process during which the tips are formed at the liquid/air interface. A statistical analysis of the surface morphology has been carried out on a set of 60 tips by scanning electron microscopy. The results show that the surface roughness and the sharpness of the final tip are critically influenced by the intrinsic granularity of the gold wires. Moreover, there is a correlation between the tip quality and the time elapse required to complete the low-voltage etching step. Tips featuring smooth surfaces and radii of curvature <50 nm are produced whenever the etching times are lower than 250 s, while etching times larger than 300 s typically yield rough, blunt tips. Such a correlation can be used as a screening criterion to select sharp tips during production with an 80% yield. The high quality of the gold tips produced with such method is confirmed by the electromagnetic field enhancement measured both in tip-enhanced Raman scattering and surface-enhanced Raman scattering on the tip apex experiments.
Molecular dynamics simulation of Al grain mixing in Fe/Ni matrices and its influence on oxidation
Authors: Verners O. , Shin Y. K. , van Duin A. C. T.
Published: July 2013

AlxNiyFe(1−x−y) alloys are structural materials with potential application in high-temperature oxidizing environments. These materials are of specific interest as they have the ability to develop an oxidation resistant surface layer. To study diffusion and oxidation processes related to this surface layer formation, the mixing behavior of different sized Al grains in pure Ni and Fe matrices, with approximate grain/matrix atom ratio of 1:3, at temperatures above and below the structure melting point, was studied using ReaxFF-based molecular dynamics simulations. The simulations have been carried out at constant pressure, with temperatures being stepwise ramped over the range of 300-3000 K. For the Ni matrix, our results indicated lower chemical strain energy for Al in the mixed alloy and completion of mixing at a lower temperature for the Fe matrix. These results confirm that the Al-Ni alloy is energetically more stable than the Al-Fe alloy, which is in agreement with experiment. Further, larger Al grains appear to be favorable for mixing with Fe matrix, whereas for Ni matrix, smaller Al grains appear to be favorable. We suggest that this Al grain size effect on mixing matrices is due to the differences in formation energies between Ni/Al and Fe/Al alloys and differences in Ni-Ni and Fe-Fe bond distances. We also performed additional cooling simulations over the temperature range of 3000-300 K. The simulations revealed that for the considered cooling rate Fe alloy solidifies at a lower temperature than Ni alloy. Moreover, both alloys solidify to chemically disordered crystalline structures, of which the Ni structure is less ordered than the Fe structure. Preliminary oxidation simulations of slab structures with single grain indicate that the dynamics of matrix/grain mixing processes have a pronounced influence on the oxidation reactions. We find that Al and Ni atoms in their unmixed state are the most active reactants towards oxygen, while the Al/Ni alloy and pure Fe layers show substantially slower oxidation kinetics.
Terahertz quartz enhanced photo-acoustic sensor
Authors: Borri S. , Patimisco P. , Sampaolo A. , Beere H. E. , Ritchie D. A. , Vitiello M. S. , Scamarcio G. , Spagnolo V.
Published: July 2013

A quartz enhanced photo-acoustic sensor employing a single-mode quantum cascade laser emitting at 3.93 Terahertz (THz) is reported. A custom tuning fork with a 1 mm spatial separation between the prongs allows the focusing of the THz laser beam between them, while preventing the prongs illumination. A methanol transition with line-strength of 4.28 × 10−21 cm has been selected as target spectroscopic line. At a laser optical power of ∼ 40 μW, we reach a sensitivity of 7 parts per million in 4s integration time, corresponding to a 1σ normalized noise-equivalent absorption of 2 × 10−10 cm−1W/Hz½.
Assessments about soil temperature variation under censored data and importance for geothermal energy applications. Illustration with Romanian data
Authors: Bălan Mugur C. , Todoran Tudor P. , Bolboacă Sorana D. , Jäntschi Lorentz
Published: July 2013

The study presents an experimental research carried out to study the natural soil temperature variations and to determine the soil thermal diffusivity based solely on temperature measurements. The research was conducted for two locations in Romania: Cluj-Napoca on bare clay soil and Reghin on grass covered clay soil. It was proved that the design and methodology of the research can be successfully applied in any location. Based on a statistical analysis of the experimental data, a simple and precise mathematical model for natural temperature variation was identified for each location. An important particularity of the models is that for each parameter are presented specific ranges of variation and confidence intervals. To the best knowledge of the authors, this approach is unique in the scientific literature. Another particularity of the models is that it was obtained under censored data. The presented models are generally suitable for any depth up to 10 m. For both locations the soil thermal diffusivity was calculated with specific ranges of variation and confidence interval. The obtained results are of utmost importance for the evaluation of local soil thermal potential for geothermal energy applications.
Dynamic and dielectric response of charged colloids in electrolyte solutions to external electric fields
Authors: Zhou Jiajia , Schmitz Roman , Dünweg Burkhard , Schmid Friederike
Published: July 2013

Computer simulations are used to investigate the response of a charged colloid and its surrounding microion cloud to an external electric field. Both static fields and alternating fields are considered. A mesoscopic simulation method is implemented to account in full for hydrodynamic and electrostatic interactions. The response of the system can be characterized by two quantities: the mobility and the polarizability. Due to the interplay of the electrostatic attraction and hydrodynamic drag, the response of the microions close to the colloid surface is different from that of the microions far away from the colloid. Both the mobility and polarizability exhibit a dependency on the frequency of the external fields, which can be attributed to the concentration polarization, the mobility of the microions, and the inertia of microions. The effects of the colloidal charge, the salt concentration, and the frequency of the external fields are investigated systematically.
Two-dimensional cylindrical ion-acoustic solitary and rogue waves in ultrarelativistic plasmas
Authors: Ata-ur-Rahman  , Ali S. , Moslem W. M. , Mushtaq A.
Published: July 2013

The propagation of ion-acoustic (IA) solitary and rogue waves is investigated in a two-dimensional ultrarelativistic degenerate warm dense plasma. By using the reductive perturbation technique, the cylindrical Kadomtsev–Petviashvili (KP) equation is derived, which can be further transformed into a Korteweg–de Vries (KdV) equation. The latter admits a solitary wave solution. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency, the KdV equation can be transferred to a nonlinear Schrödinger equation to study the nonlinear evolution of modulationally unstable modified IA wavepackets. The propagation characteristics of the IA solitary and rogue waves are strongly influenced by the variation of different plasma parameters in an ultrarelativistic degenerate dense plasma. The present results might be helpful to understand the nonlinear electrostatic excitations in astrophysical degenerate dense plasmas.
Spatially dependent parameter estimation and nonlinear data assimilation by autosynchronization of a system of partial differential equations
Authors: Kramer Sean , Bollt Erik M.
Published: July 2013

Given multiple images that describe chaotic reaction-diffusion dynamics, parameters of a partial differential equation (PDE) model are estimated using autosynchronization, where parameters are controlled by synchronization of the model to the observed data. A two-component system of predator-prey reaction-diffusion PDEs is used with spatially dependent parameters to benchmark the methods described. Applications to modeling the ecological habitat of marine plankton blooms by nonlinear data assimilation through remote sensing are discussed.
The application of the thermodynamic perturbation theory to study the hydrophobic hydration
Authors: Mohorič Tomaž , Urbic Tomaz , Hribar-Lee Barbara
Published: July 2013

The thermodynamic perturbation theory was tested against newly obtained Monte Carlo computer simulations to describe the major features of the hydrophobic effect in a simple 3D-Mercedes-Benz water model: the temperature and hydrophobe size dependence on entropy, enthalpy, and free energy of transfer of a simple hydrophobic solute into water. An excellent agreement was obtained between the theoretical and simulation results. Further, the thermodynamic perturbation theory qualitatively correctly (with respect to the experimental data) describes the solvation thermodynamics under conditions where the simulation results are difficult to obtain with good enough accuracy, e.g., at high pressures.
Transparent actuator made with few layer graphene electrode and dielectric elastomer, for variable focus lens
Authors: Hwang Taeseon , Kwon Hyeok-Yong , Oh Joon-Suk , Hong Jung-Pyo , Hong Seung-Chul , Lee Youngkwan , Ryeol Choi Hyouk , Jin Kim Kwang , Hossain Bhuiya Mainul , Nam Jae-Do
Published: July 2013

A transparent dielectric elastomer actuator driven by few-layer-graphene (FLG) electrode was experimentally investigated. The electrodes were made of graphene, which was dispersed in N-methyl-pyrrolidone. The transparent actuator was fabricated from developed FLG electrodes. The FLG electrode with its sheet resistance of 0.45 kΩ/sq (80 nm thick) was implemented to mask silicone elastomer. The developed FLG-driven actuator exhibited an optical transparency of over 57% at a wavenumber of 600 nm and produced bending displacement performance ranging from 29 to 946 μm as functions of frequency and voltage. The focus variation was clearly demonstrated under actuation to study its application-feasibility in variable focus lens and various opto-electro-mechanical devices.
Heat transport of nitrogen in helium atmospheric pressure microplasma
Authors: Xu S. F. , Zhong X. X.
Published: July 2013

Stable DC atmospheric pressure normal glow discharges in ambient air were produced between the water surface and the metallic capillary coupled with influx of helium gas. Multiple independent repeated trials indicated that vibrational temperature of nitrogen rises from 3200 to 4622 K, and rotational temperature of nitrogen decreases from 1270 to 570 K as gas flux increasing from 20 to 80 sccm and discharge current decreasing from 11 to 3 mA. Furthermore, it was found that the vibrational degree of the nitrogen molecule has priority to gain energy than the rotational degree of nitrogen molecule in nonequilibrium helium microplasma.
Power enhancing by reversing mode sequence in tuned mass-spring unit attached vibration energy harvester
Authors: Kim Jae Eun , Kim Yoon Young
Published: July 2013

We propose a vibration energy harvester consisting of an auxiliary frequency-tuned mass unit and a piezoelectric vibration energy harvesting unit for enhancing output power. The proposed integrated system is so configured that its out-of-phase mode can appear at the lowest eigenfrequency unlike in the conventional system using a tuned unit. Such an arrangement makes the resulting system distinctive: enhanced output power at or near the target operating frequency and very little eigenfrequency separation, not observed in conventional eigenfrequency-tuned vibration energy harvesters. The power enhancement of the proposed system is theoretically examined with and without tip mass normalization or footprint area normalization.
Alignment and alignment transition of bent core nematics
Authors: Elamain Omaima , Hegde Gurumurthy , Komitov Lachezar
Published: July 2013

We report on the alignment of nematics consisting of bimesogen bent core molecules of chlorine substituent of benzene derivative and their binary mixture with rod like nematics. It was found that the alignment layer made from polyimide material, which is usually used for promoting vertical (homeotropic) alignment of rod like nematics, promotes instead a planar alignment of the bent core nematic and its nematic mixtures. At higher concentration of the rod like nematic component in these mixtures, a temperature driven transition from vertical to planar alignment was found near the transition to isotropic phase.
Two-dimensional electrons in periodic magnetic fields: Finite-differences method study
Authors: Zhang X. W. , Mou S. Y. , Dai B.
Published: July 2013

Using the finite-differences method, the electronic structures of two-dimensional electrons are investigated under a periodic magnetic field. To achieve accuracy, the exact profile of the magnetic field is employed in the numerical calculations. The results show that the system exhibits rich band structures, and the width of sub-bands becomes narrower as |ky| increases. In particular, many bound states are formed in the potential wells, and they are localized. Localization analysis confirms that extended, localized, and intermediate states coexist in the system, which is very different from the case without the modulated magnetic field. These results may help us to learn more about two-dimensional electrons in a periodic magnetic field.
Single-photon sampling architecture for solid-state imaging sensors
Authors: van den Berg Ewout , Candès Emmanuel , Chinn Garry , Levin Craig , Olcott Peter Demetri , Sing-Long Carlos
Published: July 2013

Significance

We propose a highly compressed readout architecture for arrays of imaging sensors capable of detecting individual photons. By exploiting sparseness properties of the input signal, our architecture can provide the same information content as conventional readout designs while using orders of magnitude fewer output channels. This is achieved using a unique interconnection topology based on group-testing theoretical considerations. Unlike existing designs, this promises a low-cost sensor with high fill factor and high photon sensitivity, potentially enabling increased spatial and temporal resolution in a number of imaging applications, including positron-emission tomography and light detection and ranging.
Evidence on the impact of sustained exposure to air pollution on life expectancy from China’s Huai River policy
Authors: Chen Yuyu , Ebenstein Avraham , Greenstone Michael , Li Hongbin
Published: July 2013

This paper's findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500 million residents of Northern China to lose more than 2.5 billion life years of life expectancy. The quasi-experimental empirical approach is based on China’s Huai River policy, which provided free winter heating via the provision of coal for boilers in cities north of the Huai River but denied heat to the south. Using a regression discontinuity design based on distance from the Huai River, we find that ambient concentrations of TSPs are about 184 μg/m
3
[95% confidence interval (CI): 61, 307] or 55% higher in the north. Further, the results indicate that life expectancies are about 5.5 y (95% CI: 0.8, 10.2) lower in the north owing to an increased incidence of cardiorespiratory mortality. More generally, the analysis suggests that long-term exposure to an additional 100 μg/m
3
of TSPs is associated with a reduction in life expectancy at birth of about 3.0 y (95% CI: 0.4, 5.6).
Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century
Authors: Emanuel Kerry A.
Published: July 2013

A recently developed technique for simulating large [O(10
4
)] numbers of tropical cyclones in climate states described by global gridded data is applied to simulations of historical and future climate states simulated by six Coupled Model Intercomparison Project 5 (CMIP5) global climate models. Tropical cyclones downscaled from the climate of the period 1950–2005 are compared with those of the 21st century in simulations that stipulate that the radiative forcing from greenhouse gases increases by

over preindustrial values. In contrast to storms that appear explicitly in most global models, the frequency of downscaled tropical cyclones increases during the 21st century in most locations. The intensity of such storms, as measured by their maximum wind speeds, also increases, in agreement with previous results. Increases in tropical cyclone activity are most prominent in the western North Pacific, but are evident in other regions except for the southwestern Pacific. The increased frequency of events is consistent with increases in a genesis potential index based on monthly mean global model output. These results are compared and contrasted with other inferences concerning the effect of global warming on tropical cyclones.
A Simple Reagent-Free Spectrophotometric Assay for Monitoring Metronidazole Therapy in Aquarium Water
Authors: Webb D. Harry , Marrero Cynthia , Ellis Helen , Merriwether Lea , Dove Alistair D. M.
Published: July 2013

A reagent-free spectrophotometric assay was developed to measure the concentration of metronidazole (a 5-nitroimidazole) in both freshwater and seawater matrices. This assay is simple, repeatable, sensitive, and precise and is ideal for use when a rapid, selective test to determine metronidazole concentration in aqueous matrices is necessary. The assay was practically tested on a South American fishes display during treatment with metronidazole for an outbreak of the flagellated parasite Spironucleus in a mixed cichlid (family Cichlidae) and tetra (family Characidae) community. The assay clearly illustrated the course of treatment for the system during a real clinical application. The assay is not without limitations, as interferences can occur from other drugs in the matrix with similar absorbance spectra. Nonetheless, this type of assay illustrates the potential for use of native absorbance assays in aqueous matrices for this and other therapeutic compounds.

Received November 29, 2012; accepted March 17, 2013
Effects of Inactivated Enterococcus faecalis and Mannan Oligosaccharide and Their Combination on Growth, Immunity, and Disease Protection in Rainbow Trout
Authors: Rodriguez-Estrada Uriel , Satoh Shuichi , Haga Yutaka , Fushimi Hiroshi , Sweetman John
Published: July 2013

We examined the effects of the following seven experimental diets that varied in the concentration of inactivated cells of Enterococcus faecalis (Ef) and mannan oligosaccharides (MOS), on Rainbow Trout Oncorhynchus mykiss: control (C) diet (no Ef and no MOS), diet E0.25% (2.5 g/kg Ef), diet E0.5% (5 g/kg Ef), diet M0.25% (2.5 g/kg MOS), diet M0.5% (5 g/kg MOS), diet EM0.25% (2.5 g/kg Ef + 2.5 g/kg MOS) and diet EM0.5% (5 g/kg Ef + 5 g/kg MOS). Rainbow Trout, initially weighing 36.27 ± 0.42 g (mean ± SD) were distributed into fourteen 60-L glass tanks at a stocking density of 35 fish per tank. Each diet was hand-fed to duplicate groups of fish twice daily for a 12-week period. After the feeding test, an intraperitoneal injection challenge test of Aeromonas salmonicida was conducted over 14 d. Resulting data were submitted to a multivariate analysis of variance. Weight gain increased significantly (P < 0.05) in E0.25%, M0.25%, and EM0.5% experimental groups compared with the control. Specific growth rate was significantly higher (P < 0.05) in fish fed E0.25%, M0.25%, and EM0.5% diets compared with fish fed the C diet. Feed gain ratio and protein efficiency ratio were significantly improved (P < 0.05) in fish fed the EM0.5% diet compared with fish fed the C diet. Feed intake, protein efficiency ratio, protein retention, and the apparent digestibility coefficient recorded slight differences within experimental groups. Hematocrit value and phagocytic activity were significantly higher (P < 0.05) in fish fed E0.25%, E0.5%, M0.5%, EM0.25%, and EM0.5% diets compared with fish fed the C diet. Except for fish in the E0.25% group, fish in all other experimental groups showed a significantly higher (P < 0.05) mucus weight compared with those in the C group. After the challenge test, cumulative mortality and frequency of A. salmonicida were significantly decreased (P < 0.05) in all experimental groups compared with the C group. In conclusion, dosage and single or combined supplementation of Ef and MOS are factors that significantly affect fish performance.
Climate and choice of irrigation technology: implications for climate adaptation
Authors: Frisvold George B. , Deva Shailaja
Published: July 2013

Because studies of irrigation technology adoption often concentrate on small geographic areas with the same climate, few have estimated effects of climate on irrigation technology choice. This study examines the choice of sprinkler versus gravity-flow irrigation across 17 western states. Analysis considers long-term seasonal temperatures and growing season length. An erosion index captures effects of rainfall, field slope, and soil water-holding capacity. Sprinkler adoption increases with reliance on groundwater, pumping costs, farm wage growth, and erosion. Sprinkler adoption was significantly lower for smaller farms. In colder climates, climate warming may lengthen the growing season, but increase susceptibility to frost during the expanded growth period, which may encourage sprinkler adoption. In warmer areas, there is less scope to adapt to warming by switching from gravity to sprinkler technology. Sprinkler adoption declines monotonically in Spring/Summer temperature and growing-season-adjusted Fall/Winter temperature. A drier climate would reduce sprinkler adoption, while climates with more rainfall and more intense rain events would see greater adoption.
Hsp90 Is Required for Pheromone Signaling in Yeast
Authors: Louvion Jean-François , Abbas-Terki Toufik , Picard Didier
Published: July 2013

The heat-shock protein 90 (Hsp90) is a cytosolic molecular chaperone that is highly abundant even at normal temperature. Specific functions for Hsp90 have been proposed based on the characterization of its interactions with certain transcription factors and kinases including Raf in vertebrates and flies. We therefore decided to address the role of Hsp90 for MAP kinase pathways in the budding yeast, an organism amenable to both genetic and biochemical analyses. We found that both basal and induced activities of the pheromone-signaling pathway depend on Hsp90. Signaling is defective in strains expressing low levels or point mutants of yeast Hsp90 (Hsp82), or human Hsp90β instead of the wild-type protein. Ste11, a yeast equivalent of Raf, forms complexes with wild-type Hsp90 and depends on Hsp90 function for accumulation. For budding yeast, Ste11 represents the first identified endogenous “substrate” of Hsp90. Moreover, Hsp90 functions in steroid receptor and pheromone signaling can be genetically separated as the Hsp82 point mutant T525I and the human Hsp90β are specifically defective for the former and the latter, respectively. These findings further corroborate the view that molecular chaperones must also be considered as transient or stable components of signal transduction pathways.
Identification of Darlin, aDictyosteliumProtein withArmadillo-like Repeats that Binds to Small GTPases and Is Important for the Proper Aggregation of Developing Cells
Authors: Vithalani Kalpa K. , Parent Carole A. , Thorn Eric M. , Penn Marcus , Larochelle Denis A. , Devreotes Peter N. , De Lozanne Arturo
Published: July 2013

We purified from Dictyosteliumlysates an 88-kDa protein that bound to a subset of small GTPases, including racE, racC, cdc42Hs, and TC4ran, but did not bind to R-ras or rabB. Cloning of the gene encoding this 88-kDa protein revealed that it contained multiple armadillo-like repeats most closely related to the mammalian GTP exchange factor smgGDS. We named this protein darlin (Dictyostelium armadillo-like protein). Disruption of the gene encoding darlin demonstrated that this protein is not essential for cytokinesis, pinocytosis, phagocytosis, or development. However, the ability of darlin null cells to aggregate in response to starvation is severely affected. When starved under liquid medium, the mutant cells were unable to form aggregation centers and streams, possibly because of a defect in cAMP relay signaling. This defect was not due to an inability of the darlin mutants to activate adenylate cyclase in response to G protein stimulation. These results suggest that the darlin protein is involved in a signaling pathway that may modulate the chemotactic response during early development.
The Three-dimensional Study of Chromosomes and Upstream Binding Factor-immunolabeled Nucleolar Organizer Regions Demonstrates Their Nonrandom Spatial Arrangement during Mitosis
Authors: Klein Christophe , Cheutin Thierry , O’Donohue Marie-Françoise , Rothblum Lawrence , Kaplan Hervé , Beorchia Adrien , Lucas Laurent , Héliot Laurent , Ploton Dominique
Published: July 2013

The volumic rearrangement of both chromosomes and immunolabeled upstream binding factor in entire well-preserved mitotic cells was studied by confocal microscopy. By using high-quality three-dimensional visualization and tomography, it was possible to investigate interactively the volumic organization of chromosome sets and to focus on their internal characteristics. More particularly, this study demonstrates the nonrandom positioning of metaphase chromosomes bearing nucleolar organizer regions as revealed by their positive upstream binding factor immunolabeling. During the complex morphogenesis of the progeny nuclei from anaphase to late telophase, the equal partitioning of the nucleolar organizer regions is demonstrated by quantification, and their typical nonrandom central positioning within the chromosome sets is revealed.
Genes and Politics: A New Explanation and Evaluation of Twin Study Results and Association Studies in Political Science
Authors: Shultziner Doron
Published: July 2013

This article offers a new explanation for the results of twin studies in political science that supposedly disclose a genetic basis for political traits. I argue that identical twins tend to be more alike than nonidentical twins because the former are more similarly affected by the same environmental conditions, but the content of those greater trait similarities is nevertheless completely malleable and determined by particular environments. The twin studies method thus can neither prove nor refute the argument for a genetic basis of political traits such as liberal and conservative preferences or voting turnout. The meaning of heritability estimates results in twin studies are discussed, as well as the definition and function of the environment in the political science twin studies. The premature attempts to associate political traits with specific genes despite countertrends in genetics are also examined. I conclude by proposing that the alternative explanation of this article may explain certain puzzles in behavioral genetics, particularly why social and political traits have higher heritability estimates than common physical and medical traits. I map the main point of disagreements with the methodology and the interpretation of its results, and delineate the main operative implications for future research.
Capital and income breeding traits differentiate trophic match–mismatch dynamics in large herbivores
Authors: Kerby Jeffrey , Post Eric
Published: July 2013

For some species, climate change has altered environmental conditions away from those in which life-history strategies evolved. In such cases, if adaptation does not keep pace with these changes, existing life-history strategies may become maladaptive and lead to population declines. We use life-history theory, with a specific emphasis on breeding strategies, in the context of the trophic match–mismatch framework to form generalizable hypotheses about population-level consumer responses to climate-driven perturbations in resource availability. We first characterize the income and breeding traits of sympatric caribou and muskoxen populations in western Greenland, and then test trait-based hypotheses about the expected reproductive performance of each population during a period of high resource variability at that site. The immediate reproductive performance of income breeding caribou decreased with trophic mismatch. In contrast, capital breeding muskoxen were relatively unaffected by current breeding season resource variability, but their reproductive performance was sensitive to resource conditions from previous years. These responses matched our expectations about how capital and income breeding strategies should influence population susceptibility to phenological mismatch. We argue for a taxon-independent assessment of trophic mismatch vulnerability based on a life-history strategy perspective in the context of prevailing environmental conditions.
3a-Phenyl-2,3,3a,4-tetrahydro-1H-benzo[d]pyrrolo[1,2-a]imidazol-1-one, a potential plant-growth regulator
Authors: Grinev Vyacheslav S. , Egorova Alevtina Yu.
Published: July 2013

Molecules of the title compound, C16H14N2O, a potential plant-growth regulator, are linked into chains by intermolecular C=O...H—N hydrogen bonds. These chains are weakly interconnected by π–π stacking interactions to form a three-dimensional framework. A comparison of the geometric parameters of the title molecule and several related benzimidazoles and pyrrolidones is presented.
1,7-Dideaza-2′-deoxy-6-nitronebularine: a pyrrolo[2,3-b]pyridine nucleoside with an intramolecular hydrogen bond stabilizing thesynconformation
Authors: Yang Haozhe , Budow Simone , Eickmeier Henning , Reuter Hans , Seela Frank
Published: July 2013

The title compound [systematic name: 1-(2-deoxy-β-D-erythro-pentofuranosyl)-4-nitro-1H-pyrrolo[2,3-b]pyridine], C12H13N3O5, forms an intramolecular hydrogen bond between the pyridine N atom as acceptor and the 5′-hydroxy group of the sugar residue as donor. Consequently, the N-glycosylic bond exhibits asynconformation, with a χ torsion angle of 61.6 (2)°, and the pentofuranosyl residue adopts a C2′-endoenvelope conformation (2E,S-type), withP= 162.1 (1)° and τm= 36.2 (1)°. The orientation of the exocyclic C4′—C5′ bond is +sc(gauche,gauche), with a torsion angle γ = 49.1 (2)°. The title nucleoside forms an ordered and stacked three-dimensional network. The pyrrole ring of one layer faces the pyridine ring of an adjacent layer. Additionally, intermolecular O—H...O and C—H...O hydrogen bonds stabilize the crystal structure.
The supramolecular structure of a cadmium complex with the new functionalized terpyridine ligand 4′-[4-(pyrimidin-5-yl)phenyl]-2,2′:6′,2′′-terpyridine (L1): aqua(L1-κ3N,N′,N′′)(nitrato-κ2O,O′)(nitrato-κO)cadmium(II) dihydrate
Authors: Granifo Juan , Gaviño Rubén , Freire Eleonora , Baggio Ricardo
Published: July 2013

The monomeric title compound, aqua(nitrato-κ2O,O′)(nitrato-κO){4′-[4-(pyrimidin-5-yl)phenyl]-2,2′:6′,2′′-terpyridine-κ3N,N′,N′′}cadmium(II) dihydrate, [Cd(NO3)2(C25H17N5)(H2O)]·2H2O, consists of a seven-coordinated CdIIcentre bound to the novel 4′-[4-(pyrimidin-5-yl)phenyl]-2,2′:6′,2′′-terpyridine (L1) ligand (behaving as a tridentate chelate), two nitrate anions (as chelating–bidentate and monodentate ligands) and a water O atom. Both chelating groups define the base of a slightly deformed pentagonal bipyramid, while the monocoordinated ligands occupy the apices. The four heterocycles inL1 form a planar skeleton, while the central benzene ring is rotated from this planar geometry by more than 30°, probably because of packing effects. Noncovalent interactions lead to the formation of columnar arrays parallel to [100].
Hydrogen-bonded bilayers in 7-benzyl-3-tert-butyl-1-phenyl-4,5,6,7-tetrahydro-1H-spiro[pyrazolo[3,4-b]pyridine-5,2′-indan]-1′,3′-dione
Authors: Quiroga Jairo , Pantoja Dayana , Cobo Justo , Glidewell Christopher
Published: July 2013

In the title compound, C31H29N3O2, the reduced pyridine ring adopts a conformation intermediate between the envelope and half-chair forms. The aryl rings of the benzyl and phenyl substituents are nearly parallel and overlap, indicative of an intramolecular π–π stacking interaction. A combination of two C—H...O hydrogen bonds and one C—H...N hydrogen bond links the molecules into a bilayer havingtert-butyl groups on both faces.
An unexpected tetragonal unit cell forN-(L-2-aminobutyryl)-L-serine
Authors: Görbitz Carl Henrik , Yadav Vitthal N.
Published: July 2013

The title dipeptide {systematic name: (S)-2-[(S)-2-azaniumylbutanamido]-3-hydroxypropanoate}, C7H14N2O4, was synthesized in the anticipation that it would form nanoporous crystals with hexagonal symmetry. Single-crystal X-ray diffraction analysis showed that it had instead adopted a unit cell in the space groupI4, similar to L-alanyl-L-alanine [Fletterick, Tsai & Hughes (1970).J. Phys. Chem.75, 918–922]. The resulting packing arrangement has a high density for a peptide (1.462 Mg m−3), which is rendered possible by extensive disorder over two positions for the ethyl side chain of the 2-aminobutyric acid fragment and over three positions for the serine side chain.
Boundary layer flow of a nanofluid over an exponentially stretching sheet with convective boundary conditions
Authors: Mustafaa M. , Hayat T. , Obaidat S.
Published: July 2013

Purpose

This paper aims to discuss the flow and heat transfer characteristics over an exponentially stretching sheet in a nanofluid with convective boundary conditions. The effects of Brownian motion and thermophoresis are also accounted.

Design/methodology/approach

The flow is therefore governed by the Brownian motion parameter (Nb), the thermophoresis parameter (Nt), the Prandtl number (Pr), the Lewis number (Le) and the Biot number (Bi). The analytic solutions of the arising differential systems have been obtained by homotopy analysis method (HAM).

Findings

The temperature rises and the thermal boundary layer thickens with an increase in the Brownian motion and thermophoresis parameters. The surface heat and mass transfer appreciably increase with an increase in the Prandtl and Lewis numbers.

Originality/value

The presented results also include the analysis for constant wall temperature.
Supporting the educational transitions of looked after children at Key Stage 4: the role of virtual schools and designated teachers
Authors: Driscoll Jennifer
Published: July 2013

Purpose

There has been little research on the education of looked after children over the current school leaving age of 16, although the underperformance of this cohort at Key Stage 4 (age 14‐16) has been the subject of considerable academic commentary. This paper aims to contribute to understanding of the ways in which looked after young people nearing the end of compulsory education can be supported and encouraged to continue in education and training.

Design/methodology/approach

Interviews were undertaken with 12 designated teachers for looked after children and four virtual school heads, as part of the first stage of a three‐year longitudinal study following 20 looked after children in England from years 11‐13 (ages 15‐18).

Findings

Participants identified particular challenges in ensuring a successful educational transition for looked after young people in year 11 and expressed concern at the cumulative effect of multiple transitions at this stage on young people's lives. There appears, however, to be an increasing focus on and commitment to giving young people a “second chance” to acquire qualifications commensurate with their potential post‐16. The comparative advantages and disadvantages of school and further education colleges for this cohort at Key Stage 5 are considered.

Practical implications

The implications of the forthcoming extension of the school leaving age for professionals supporting looked after young people post‐16 are discussed.

Originality/value

The designated teacher for looked after children became a statutory role in 2009, and to date there has been little research on the role of these professionals, or the work of virtual schools.