bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of multi‐objective fractional factorial design for ultra‐wideband antennas with uniform gain and high fidelity
Authors: Chen Yen‐Sheng
Published: August 2015

An efficient design methodology is presented for developing ultra‐wideband (UWB) antennas with uniform gain and high fidelity. The major challenge for designing UWB antennas is to simultaneously meet all the frequency‐domain and time‐domain performance criteria including good impedance matching throughout the operational frequencies, relatively uniform gain over the UWB, and high waveform fidelity on pulse‐preserving capabilities. If the framework of Pareto‐based evolutionary algorithms is adopted, it may require thousands of tests to find an optimum structure due to the blind‐search feature. In this study, all the requirements of UWB antenna design can now be efficiently achieved by the proposed methodology, which integrates the processes of fractional factorial design of experiments and Derringer's desirability functions into a multi‐objective optimisation technique. The detailed procedure and its capability are demonstrated by an UWB planar monopole antenna design which comprises nine design parameters. By performing merely 64 predefined simulations, the optimum antenna structure is determined with an excellent impedance matching by 2:1 voltage standing wave ratio and a relatively constant gain (2.48–5.04 dBi) over the frequency band of 3.1–10.6 GHz. Meanwhile, the time‐domain distortion is greatly reduced in comparison with the reference design which simply optimises the characteristic of impedance matching.
Scenarios for use of floating photovoltaic plants in Brazilian reservoirs
Authors: Sacramento Elissandro Monteiro do , Carvalho Paulo C.M. , de Araújo Jose Carlos , Riffel Douglas Bressan , Corrêa Ronne Michel da Cruz , Pinheiro Neto José Sigefredo
Published: August 2015

The conversion efficiency of a crystalline silicon photovoltaic (PV) module increases as its temperature decreases. Considering this characteristic of the PV technology, in this study the authors analyse the use of cooled floating PV modules in a fraction of the area occupied by three reservoirs – Castanhão, Orós and Banabuiú – in the Brazilian semi‐arid region. Comparing with conventional ground‐mounted PV modules, an average conversion efficiency increase of 12.5% was measured for floating PV modules under the local weather conditions. In a second phase, measurements are used as input data in the PVSYST software in conjunction with a spreadsheet for the construction of electricity production scenarios. According to these scenarios, the potential PV production in the mentioned reservoirs would supply 7.4 and 18.8% of the electricity demand of Brazil's Ceará state (8.84 million inhabitants) and its largest city Fortaleza (2.6 million inhabitants), respectively.
Multiple input and multiple output synthetic aperture radar multiple waveform separation based on oblique projection in same frequency coverage
Authors: Meng Cang‐Zhen , Xu Jia , Liu Feng , Long Teng , Yang Jian , Peng Ying‐Ning
Published: August 2015

In multiple input and multiple output synthetic aperture radar (MIMO‐SAR) the unwanted cross‐correlation output sexist inevitably in the superposed echoes of multiple transmitted orthogonal waveforms in the same frequency coverage, which may deteriorate the quality of the reconstructed SAR image because of the high synthetic integrated sidelobe level (SISL). In this study, a novel signal decomposition based on oblique projection (SDOP) method is proposed to suppress the cross‐correlation outputs. At first, the superposed echo of each receiver is modelled as a linear‐combined vector of transmitted multiple waveforms. Then, the echo of each transmitted waveform is obtained by signal decomposition on the combined vector via SDOP, respectively. Besides, two new metrics, that is, synthetics integrated sidelobe level ratio improved factor and integrated sidelobe level ratio loss factor, are also proposed to assess the separation performance. It is found that the cross‐correlation can be effectively suppressed among multiple waveforms via low‐complexity projection operators and the output signal noise ratio can be remarkably improved, accordingly. Finally, the numerical experiments are also provided to demonstrate the effectiveness of the proposed method.
Imaging and micro‐Doppler analysis of vibrating target in multi‐input–multi‐output synthetic aperture radar
Authors: Zhao Guanhua , Fu Yaowen , Nie Lei , Zhuang Zhaowen
Published: August 2015

The micro‐Doppler (m‐D) signature induced by the micro‐motion dynamics of a component or structure on a radar target can provide additional information for classification, recognition, and identification of the object. Since the m‐D signature from conventional synthetic aperture radar (SAR) is insufficient for further application, attention centred on multi‐input–multi‐output (MIMO) SAR. MIMO SAR employs diversity to improve SAR performance and shows great potential in applications including high‐resolution wide‐swath remote sensing, slow moving target detection, and three‐dimensional (3D) imaging. Take vibration for research, because vibration is a basic kind of micro‐motion and it occurs commonly such as vehicle engine. In this study, the vibration signal modelling is deduced and the m‐D signature of vibrating target is analysed, based on short‐term shift‐orthogonal waveform in MIMO SAR. Simulations verify the influence of vibration parameters on imaging and time–frequency profile and show the m‐D signature difference through different MIMO channels. The results demonstrate the potential of MIMO SAR for 3D micro‐motion estimation.
Altitude measurement of low‐angle target in complex terrain for very high‐frequency radar
Authors: Zheng Yisong , Chen Baixiao
Published: August 2015

For low‐angle targets, the performance of altitude measurement is affected by multipath phenomenon. Especially, for complex terrain case, the main problem is due to the fact that the multipath signal is perturbed by irregular reflector, which leads to the mismatch of the steering vector, and thus degrades the performance of or even fails the existing methods. To deal with this problem, the authors propose a new perturbational multipath signal model, where perturbation caused by complex terrain is considered as the gain and phase errors of the steering vector of the multipath signal. With the spatial sparsity of the incident signals, the sparse Bayesian learning technique is adopted to estimate the perturbation and direction of arrival (DOA) iteratively. The computer simulation results show that their algorithm is able to estimate the effect of perturbation with high precision and to enhance the DOA accuracy compared with existing algorithms. Furthermore, real data analysis validates the efficiency of altitude measurement in practice. Finally, the proposed perturbational multipath signal model is also applicable to other situations where complex multipath phenomenon is not negligible.
Sea clutter suppression method for shipborne high‐frequency surface‐wave radar
Authors: Yi Chunlei , Ji Zhenyuan , Xie Junhao , Sun Minglei , Li Yang
Published: August 2015

For detection of target submerged in the spread Doppler spectrum of the first‐order sea clutter in shipborne high‐frequency surface‐wave radar (HFSWR), there still remains a challenge. In this study, an improved orthogonal weighting (OW) algorithm is proposed for shipborne HFSWR to suppress sea clutter in both Doppler domain and spatial domain. By combining OW with the method of sea clutter suppression in Doppler domain, the performance of azimuth estimation of OW is thus preserved. Compared with OW and two‐dimensional fast Fourier transform plus digital beamforming, this new approach is verified to be more effective by simulations and real data.
Vernetzung, Koordination und Verantwortung durch Gesundheitsregionenplus: Neue gesundheitspolitische Ansätze und Entwicklungen in Bayern
Authors: Hollederer A. , Eicher A. , Pfister F. , Stühler K. , Wildner M.
Published: August 2015

Für viele Versorgungs- und Gesundheitsprobleme in der Bevölkerung braucht es passgenaue Lösungen, die auf die örtlichen Gegebenheiten Rücksicht nehmen. Um dies zu erreichen, sind professionelle Management- und Steuerungsinstrumente sowie ein fachlich kompetentes Netzwerk vor Ort nötig. Eine solche Struktur bieten die neuen „Gesundheitsregionenplus“ in Bayern, deren Fachkonzept im Kurzbeitrag vorgestellt wird. Die Gesundheitsregionenplus zielen darauf, den Gesundheitszustand der Bevölkerung zu verbessern, die gesundheitsbezogene Lebensqualität auch im Hinblick auf die gesundheitliche Chancengleichheit zu erhöhen und die wohnortnahe Gesundheitsversorgung weiterzuentwickeln. Das Bayerische Staatsministerium für Gesundheit und Pflege (StMGP) stellt für zunächst maximal 24 Landkreise und kreisfreie Städte Finanzmittel von jährlich bis zu 50 000 Euro je Gesundheitsregionplus bis Ende 2019 zur Verfügung. Zur Struktur der Gesundheitsregionenplus gehören die Einrichtung einer koordinierenden Geschäftsstelle als „Motor“, die Gründung eines Gesundheitsforums als Planungs- und Steuerungsgremium und der Aufbau von themenbezogenen Arbeitsgruppen. Die Gesundheitsregionenplus binden alle relevanten regionalen Akteure des Gesundheitswesens unter Vorsitz des Landrats bzw. Oberbürgermeisters ein. Sie wirken vorrangig in den zentralen Handlungsfeldern Gesundheitsversorgung und Prävention/Gesundheitsförderung sowie weiteren fakultativen regionalspezifischen Handlungsfeldern mit. Die Gesundheitsregionenplus werden vom Bayerischen Landesamt für Gesundheit und Lebensmittelsicherheit (LGL) fachlich begleitet und wissenschaftlich evaluiert. Eine dort eingerichtete fachliche Leitstelle stellt den Informations- und Erfahrungsaustausch zwischen den Gesundheitsregionenplus her. Ein solcher regionaler Gesamtansatz verändert zwar nicht die gesetzlich vorgegebenen Entscheidungsstrukturen und –verantwortlichkeiten, gibt den Kommunen aber ein Instrument an die Hand, die örtlichen Bedürfnisse stärker in den Entscheidungsprozess einzubringen.
On a novel representation of discrete Painlevé equations
Authors: Grammaticos B. , Ramani A.
Published: August 2015

We introduce a new representation for the discrete Painlevé equations. It is based on the trihomographic form previously used in conjunction with discrete Painlevé equations associated with the affine Weyl group E8(1). We show here that all discrete Painlevé equations do possess a trihomographic form. The latter is often more convenient than the usual representation in particular when it comes to the application of the singularity confinement integrability criterion. We show how trihomographic forms can be combined in order to construct generic discrete Painlevé equations or limits thereof. A trihomographic form for the generic elliptic Painlevé equation is also derived.
Frequency-tunable superconducting resonators via nonlinear kinetic inductance
Authors: Vissers M. R. , Hubmayr J. , Sandberg M. , Chaudhuri S. , Bockstiegel C. , Gao J.
Published: August 2015

We have designed, fabricated, and tested a frequency-tunable high-Q superconducting resonator made from a niobium titanium nitride film. The frequency tunability is achieved by injecting a DC through a current-directing circuit into the nonlinear inductor whose kinetic inductance is current-dependent. We have demonstrated continuous tuning of the resonance frequency in a 180 MHz frequency range around 4.5 GHz while maintaining the high internal quality factor Qi > 180 000. This device may serve as a tunable filter and find applications in superconducting quantum computing and measurement. It also provides a useful tool to study the nonlinear response of a superconductor. In addition, it may be developed into techniques for measurement of the complex impedance of a superconductor at its transition temperature and for readout of transition-edge sensors.
Influence of the exchange-correlation functional on the quasi-harmonic lattice dynamics of II-VI semiconductors
Authors: Skelton Jonathan M. , Tiana Davide , Parker Stephen C. , Togo Atsushi , Tanaka Isao , Walsh Aron
Published: August 2015

We perform a systematic comparison of the finite-temperature structure and properties of four bulk semiconductors (PbS, PbTe, ZnS, and ZnTe) predicted by eight popular exchange-correlation functionals from quasi-harmonic lattice-dynamics calculations. The performance of the functionals in reproducing the temperature dependence of a number of material properties, including lattice parameters, thermal-expansion coefficients, bulk moduli, heat capacities, and phonon frequencies, is evaluated quantitatively against available experimental data. We find that the phenomenological over- and under-binding characteristics of the local-density approximation and the PW91 and Perdew-Burke-Enzerhof (PBE) generalised-gradient approximation (GGA) functionals, respectively, are exaggerated at finite temperature, whereas the PBEsol GGA shows good general performance across all four systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) and revTPSS meta-GGAs provide relatively small improvements over PBE, with the latter being better suited to calculating structural and dynamical properties, but both are considerably more computationally demanding than the simpler GGAs. The dispersion-corrected PBE-D2 and PBE-D3 functionals perform well in describing the lattice dynamics of the zinc chalcogenides, whereas the lead chalcogenides appear to be challenging for these functionals. These findings show that quasi-harmonic calculations with a suitable functional can predict finite-temperature structure and properties with useful accuracy, and that this technique can serve as a means of evaluating the performance of new functionals in the future.
Quantum heat transport of a two-qubit system: Interplay between system-bath coherence and qubit-qubit coherence
Authors: Kato Akihito , Tanimura Yoshitaka
Published: August 2015

We consider a system consisting of two interacting qubits that are individually coupled to separate heat baths at different temperatures. The quantum effects in heat transport are investigated in a numerically rigorous manner with a hierarchial equations of motion (HEOM) approach for non-perturbative and non-Markovian system-bath coupling cases under non-equilibrium steady-state conditions. For a weak interqubit interaction, the total system is regarded as two individually thermostatted systems, whereas for a strong interqubit interaction, the two-qubit system is regarded as a single system coupled to two baths. The roles of quantum coherence (or entanglement) between the two qubits (q-q coherence) and between the qubit and bath (q-b coherence) are studied through the heat current calculated for various strengths of the system-bath coupling and interqubit coupling for high and low temperatures. The same current is also studied using the time convolutionless (TCL) Redfield equation and using an expression derived from the Fermi golden rule (FGR). We find that the HEOM results exhibit turnover behavior of the heat current as a function of the system-bath coupling strength for all values of the interqubit coupling strength, while the results obtained with the TCL and FGR approaches do not exhibit such behavior, because they do not possess the capability of treating the q-b and q-q coherences. The maximum current is obtained in the case that the q-q coherence and q-b coherence are balanced in such a manner that coherence of the entire heat transport process is realized. We also find that the heat current does not follow Fourier’s law when the temperature difference is very large, due to the non-perturbative system-bath interactions.
Capacitive and resistive double sheath model in an asymmetric radio frequency plasma discharge
Authors: Faudot E.
Published: August 2015

The double asymmetric probe model presented here solves the rectified rf potential and rf currents in an asymmetric rf discharge as a function of the electrode surface ratio S1/S2, the rf potential compared to the floating potential, and the sheath capacitances on both sides of the discharge. It is demonstrated that this asymmetric unmagnetized model can be applied to a magnetized double probe one in which the asymmetry arises from the anisotropy between parallel and perpendicular currents. Asymptotic solutions for highly asymmetric discharges yield a dc saturation current on the rf electrode equal to −Isat/2 for low sheath capacitance and −Isat for high sheath capacitance. The transition capacitance between “low” and “high” is defined as C0. A solution of the rf averaged current and rectified potential as a function of the surface ratio and the rf potential are also proposed for each regime. These analytical solutions are confirmed by the full numerical model taking into account the generator resistance and the plasma conductivity.
Second order classical perturbation theory for the sticking probability of heavy atoms scattered on surfaces
Authors: Sahoo Tapas , Pollak Eli
Published: August 2015

A second order classical perturbation theory is developed to calculate the sticking probability of a particle scattered from an uncorrugated thermal surface. An analytic expression for the temperature dependent energy loss of the particle to the surface is derived by employing a one-dimensional generalized Langevin equation. The surface temperature reduces the energy loss, since the thermal surface transfers energy to the particle. Using a Gaussian energy loss kernel and the multiple collision theory of Fan and Manson [J. Chem. Phys. 130, 064703 (2009)], enables the determination of the fraction of particles trapped on the surface after subsequent momentum reversals of the colliding particle. This then leads to an estimate of the trapping probability. The theory is tested for the model scattering of Ar on a LiF(100) surface. Comparison with numerical simulations shows excellent agreement of the analytical theory with simulations, provided that the energy loss is determined by the second order perturbation theory.
Electronic and magnetic properties of nonmetal atoms adsorbed ReS2 monolayers
Authors: Zhang Xiaoou , Li Qingfang
Published: August 2015

The stable configurations and electronic and magnetic properties of nonmetal atoms (H, N, P, O, S, F, and Cl) adsorbed ReS2 monolayers have been investigated by first-principles calculations. It is found that H, O, S, F, and Cl prefer to occupy the peak sites of S atoms, while both N and P atoms favor the valley sites of S atoms. The ReS2 sheet exhibits a good adsorption capability to nonmetal atoms. The reconstruction of the surface is pronounced in N- and P-adsorbed ReS2 monolayers. In H-adsorbed case, the Fermi level is pulled into the conduction band, which results in the semiconductor-metal transition. The same magnetic moment of 1μB is found in the N-, P-, F-, and Cl-adsorbed ReS2 monolayers, while the mechanisms of forming magnetic moment for N (P)- and F (Cl)-adsorbed cases are different. In addition, the spatial extensions of spin density in P-, F-, and Cl-adsorbed cases are larger than that in N-adsorbed case, which is more suitable to achieve long-range magnetic coupling interaction at low defect concentrations. Our results provide insight for achieving metal-free magnetism and a tunable band gap for various electronic and spintronic devices based on ReS2.
Thermal ion orbit loss and radial electric field in DIII-D
Authors: deGrassie J. S. , Boedo J. A. , Grierson B. A.
Published: August 2015

A relatively simple model for the generation of the radial electric field, Er, near the outboard boundary in a tokamak is presented. The model posits that Er is established to supply the return current necessary to balance the thermal ion orbit loss current. Comparison with DIII-D data is promising. Features of the model that promote a more negative edge Er are higher ion temperature, lower density, lower impurity ion content, and a shorter pathlength for orbit loss. These scalings are consistent with experimentally established access to the high-confinement mode edge transport barrier.
Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination
Authors: Krasik Ya. E. , Leopold J. G.
Published: August 2015

In this paper, experiments are described in which cylindrical vacuum insulator samples and samples inclined at 45° relative to the cathode were stressed by microsecond timescale high-voltage pulses and illuminated by focused UV laser beam pulses. In these experiments, we were able to distinguish between flashover initiated by the laser producing only photo-electrons and when plasma is formed. It was shown that flashover is predominantly initiated near the cathode triple junction. Even dense plasma formed near the anode triple junction does not necessarily lead to vacuum surface flashover. The experimental results directly confirm our conjecture that insulator surface breakdown can be avoided by preventing its initiation [J. G. Leopold et al., Phys. Rev. ST Accel. Beams 10, 060401 (2007)] and complement our previous experimental results [J. Z. Gleizer et al., IEEE Trans. Dielectr. Electr. Insul. 21, 2394 (2014) and J. Z. Gleizer et al., J. Appl. Phys. 117, 073301 (2015)].
An analytic formula for the relativistic incoherent Thomson backscattering spectrum for a drifting bi-Maxwellian plasma
Authors: Naito O.
Published: August 2015

An analytic formula has been derived for the relativistic incoherent Thomson backscattering spectrum for a drifting anisotropic plasma when the scattering vector is parallel to the drifting direction. The shape of the scattering spectrum is insensitive to the electron temperature perpendicular to the scattering vector, but its amplitude may be modulated. As a result, while the measured temperature correctly represents the electron distribution parallel to the scattering vector, the electron density may be underestimated when the perpendicular temperature is higher than the parallel temperature. Since the scattering spectrum in shorter wavelengths is greatly enhanced by the existence of drift, the diagnostics might be used to measure local electron current density in fusion plasmas.
The mystery of missing species in atom probe tomography of composite materials
Authors: Karahka M. , Xia Y. , Kreuzer H. J.
Published: August 2015

There is a serious problem in atom probe tomography of composite materials such as oxides that even from stoichiometric samples one observes non-stoichiometric ion yields. We present a quantitative model that explains the non-stoichiometry allowing a fit to experimental data of ion yields as a function of applied field to extract activation barriers and prefactors. The numbers are confirmed by density functional theory. We also show that for oxides the missing oxygen is thermally desorbed as neutral O2, either directly or associatively. Finally, we suggest methods to improve the experimental setup.
Analysis of the contact resistance in amorphous InGaZnO thin film transistors
Authors: Wang Wei , Li Ling , Lu Congyan , Liu Yu , Lv Hangbing , Xu Guangwei , Ji Zhuoyu , Liu Ming
Published: August 2015

Contact resistance has great impact on the performance of oxide thin film transistors (TFTs) and their applications. In this letter, temperature, gate voltage, and electrode dependences of the contact resistance were investigated in amorphous InGaZnO (a-IGZO) TFTs. We found that gate voltage dependent contact resistance made a large contribution to or even dominated the “field effect” of oxide TFTs. After separating the influence of contact resistance, the intrinsic temperature dependent field effect mobility of the a-IGZO TFTs was obtained. Furthermore, the experimental data of the contact resistance can be well described by an optimized transmission line model, and the height of the Schottky barrier in the interface between the metal electrode and a-IGZO semiconductor was found to be related to the gate voltage and account for the contact resistance's dependence on the gate voltage.
Communication: Quantitative multi-site frequency maps for amide I vibrational spectroscopy
Authors: Reppert Mike , Tokmakoff Andrei
Published: August 2015

An accurate method for predicting the amide I vibrational spectrum of a given protein structure has been sought for many years. Significant progress has been made recently by sampling structures from molecular dynamics simulations and mapping local electrostatic variables onto the frequencies of individual amide bonds. Agreement with experiment, however, has remained largely qualitative. Previously, we used dipeptide fragments and isotope-labeled constructs of the protein G mimic NuG2b as experimental standards for developing and testing amide I frequency maps. Here, we combine these datasets to test different frequency-map models and develop a novel method to produce an optimized four-site potential (4P) map based on the CHARMM27 force field. Together with a charge correction for glycine residues, the optimized map accurately describes both experimental datasets, with average frequency errors of 2–3 cm−1. This 4P map is shown to be convertible to a three-site field map which provides equivalent performance, highlighting the viability of both field- and potential-based maps for amide I spectral modeling. The use of multiple sampling points for local electrostatics is found to be essential for accurate map performance.
Solid–Liquid Reaction Synthesis of High-Purity Potassium Hexathionate and Its Antibacterial Properties
Authors: Li Guofang , Xia Yahui , Zhao Yanbao , Li Ping , Zhang Fuqiang , Qu Peng
Published: August 2015

Hexathionate, an intermediate in the oxidation process of inorganic sulfur compounds, plays important roles in different fields of chemistry, chemical technology, and biology. To achieve innovative results in different fields related to polythionates, the use of hexathionate is crucial, however, it is not yet commercially available. Herein, we report a simple and convenient method to prepare high-purity potassium hexathionate. Hexathionic acid was easily synthesised through a solid–liquid reaction between sodium thiosulfate (solid) and disulfur dichloride. The potassium salt crude product was obtained by neutralising hexathionate acid with potassium hydroxide, and was purified successively using 0.1 M sulfuric acid and 0.5 M hydrochloric acid. A high product purity of 99.8 % (titrimetric analysis, 98.81 %) was obtained. The antibacterial activities of potassium hexathionate against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa) were determined by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses and the cup diffusion method. Potassium hexathionate displayed more effective antibacterial activities against P. aeruginosa than S. aureus. The MICs against P. aeruginosa and S. aureus were 1.95 and 125 µg mL–1, respectively. The corresponding MBC value against P. aeruginosa was 1000 µg mL–1. Furthermore, the duration of the antimicrobial activity, determined by the cup diffusion, shows the potential of potassium hexathionate as a sustained antibacterial candidate. However, there is no bactericidal activity against S. aureus in the concentration range tested.
Simultaneous Allocation of Bundled Goods through Auctions: Assessing the Case for Joint Bidding
Authors: Rondeau Daniel , Courty Pascal , Doyon Maurice
Published: August 2015

We study the costs and benefits of allowing joint bidding in multiple simultaneous first price sealed bid auctions for bundled goods with private values. Joint bidding raises the prospect of higher allocative efficiency but also reduces the number of bidders, resulting in an ambiguous net impact on seller revenue. The research was carried out using laboratory experiments in which groups of up to six buyers competed for eight bundles of two separable goods each. The main results show that in our experimental environment, allowing joint bidding increases efficiency by 11.3% and revenue by 9.4%. The research has immediate applications to the sale of public forest stands that arbor a mixture of species. For this reason, we explore how the results are affected by excess supply, the presence of dominant firms, and the removal of an allocation rule requiring multiple bidders under certain circumstances.
Endothelial Activation Is Associated With Cognitive Performance in Patients With Hypertension
Authors: Uiterwijk Renske , Huijts Marjolein , Staals Julie , Rouhl Rob P. W. , De Leeuw Peter W. , Kroon Abraham A. , Van Oostenbrugge Robert J.
Published: August 2015

BACKGROUND

Hypertension is associated with the occurrence of cognitive deficits and dementia, probably because hypertension is a major risk factor for the occurrence of brain damage as a result of cerebral small vessel disease (cSVD). Endothelial activation and inflammation have been suggested to play an important role in the pathogenesis of cSVD. We investigated if compound scores of endothelial activation or inflammation, based on several blood markers, are associated with cognitive performance 3 years later in patients with essential hypertension.

METHODS

At baseline, levels of blood markers of endothelial activation (soluble vascular cellular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), sP-selectin, and sE-selectin) and markers of inflammation (neopterin, C-reactive protein, and sICAM-1) were measured and transformed into compound scores using z -scores. In addition, a brain magnetic resonance imaging (MRI) was performed to determine the presence of cSVD-related MRI markers. Three years later, patients underwent a neuropsychological assessment to determine cognitive performance.

RESULTS

A total of 101 patients with hypertension were included in the present study. In multiple linear regression analyses with correction for demographics and MRI markers, the compound score of endothelial activation ( B = −0.19, 95% confidence interval = −0.34 to −0.04, P = 0.014), but not of inflammation ( B = −0.09, 95% confidence interval = −0.22 to 0.05, P = 0.198), was associated with worse cognitive performance.

CONCLUSIONS

Our results show that an overall measure of endothelial activation is associated with cognitive performance in patients with essential hypertension. This indicates that a process involving endothelial activation might play a role in the pathogenesis of cognitive problems in patients with hypertension.
Causal mediation analysis for longitudinal data with exogenous exposure
Authors: Bind M.-A. C. , Vanderweele T. J. , Coull B. A. , Schwartz J. D.
Published: August 2015

Mediation analysis is a valuable approach to examine pathways in epidemiological research. Prospective cohort studies are often conducted to study biological mechanisms and often collect longitudinal measurements on each participant. Mediation formulae for longitudinal data have been developed. Here, we formalize the natural direct and indirect effects using a causal framework with potential outcomes that allows for an interaction between the exposure and the mediator. To allow different types of longitudinal measures of the mediator and outcome, we assume two generalized mixed-effects models for both the mediator and the outcome. The model for the mediator has subject-specific random intercepts and random exposure slopes for each cluster, and the outcome model has random intercepts and random slopes for the exposure, the mediator, and their interaction. We also expand our approach to settings with multiple mediators and derive the mediated effects, jointly through all mediators. Our method requires the absence of time-varying confounding with respect to the exposure and the mediator. This assumption is achieved in settings with exogenous exposure and mediator, especially when exposure and mediator are not affected by variables measured at earlier time points. We apply the methodology to data from the Normative Aging Study and estimate the direct and indirect effects, via DNA methylation, of air pollution, and temperature on intercellular adhesion molecule 1 (ICAM-1) protein levels. Our results suggest that air pollution and temperature have a direct effect on ICAM-1 protein levels (i.e. not through a change in ICAM-1 DNA methylation) and that temperature has an indirect effect via a change in ICAM-1 DNA methylation.
Asymptomatic Bacteriuria Treatment Is Associated With a Higher Prevalence of Antibiotic Resistant Strains in Women With Urinary Tract Infections
Authors: Cai Tommaso , Nesi Gabriella , Mazzoli Sandra , Meacci Francesca , Lanzafame Paolo , Caciagli Patrizio , Mereu Liliana , Tateo Saverio , Malossini Gianni , Selli Cesare , Bartoletti Riccardo
Published: August 2015

Background.  Women suffering from recurrent urinary tract infections (rUTIs) are routinely treated for asymptomatic bacteriuria (AB), but the consequences of this procedure on antibiotic resistance are not fully known. The aim of this study was to evaluate the impact of AB treatment on antibiotic resistance among women with rUTIs.

Methods.  The study population consisted of 2 groups of women who had previously been enrolled in a randomized clinical trial: group A was not treated, and group B was treated. All women were scheduled for follow-up visits every 6 months, or more frequently if symptoms arose. Microbiological evaluation was performed only in symptomatic women. All women were followed up for a mean of 38.8 months to analyze data from urine cultures and antibiograms.

Results.  The previous study population consisted of 673 women, but 123 did not attend the entire follow-up period. For the final analysis, 257 of the remaining 550 patients were assigned to group A, and 293 to group B. At the end of follow-up, the difference in recurrence rates was statistically significant (P < .001): 97 (37.7%) in group A versus 204 (69.6%) in group B. Isolated Escherichia coli from group B showed higher resistance to amoxicillin–clavulanic acid (P = .03), trimethoprim-sulfamethoxazole (P = .01), and ciprofloxacin (P = .03) than that from group A.

Conclusions.  This study shows that AB treatment is associated with a higher occurrence of antibiotic-resistant bacteria, indicating that AB treatment in women with rUTIs is potentially dangerous.
An ecosystem approach to mixed fisheries: technical and biological interactions in the Portuguese multi-gear fleet
Authors: Cardoso Inês , Moura Teresa , Mendes Hugo , Silva Cristina , Azevedo Manuela
Published: August 2015

The term “mixed fisheries” refers to fishing activities where more than one species are caught simultaneously and one species may be fished by different gears. Therefore, mixed fisheries present a harder challenge for fisheries management than single-species fisheries and the uncertainty can start at the definition of the target species. In these particular fisheries, we have a large group of species that are caught, being target or not, species with large landing values that are actually not target, and species with a high economic value that can fall in the bycatch category. Although the dynamics of such fisheries is poorly understood, they are known to have a relevant contribution to Portuguese fishers' revenue. The present demand on sustainable fishing activities to ensure marine ecosystem preservation has led towards an ecosystem approach where effort is being made to take into account biological and technical interactions on management measures and advice. In this work, logbooks data of the Portuguese multi-gear fleet were used to identify different fisheries based on catch composition and gears through cluster analysis (CLARA). Two identified fisheries were used to explore the impact of these fishing activities on the ecosystem scale. This approach was achieved by a productivity and susceptibility analysis and through foodweb analysis. The relation between species vulnerability and their functional role in the ecosystem were highlighted. Technical interactions among fishing gears, and species biological interactions, were explored within and among fisheries. We found and illustrated that these interactions go beyond the fleets and fisheries considered in the present work. This approach allows us to identify key elements that can, ultimately, be relevant to an ecosystem-based approach towards mixed fisheries management.
Problem Solving and Goal Setting
Authors: Mohr David C.
Published: August 2015

Chapter 2 explores problem solving and goal setting. It discusses techniques for identifying problems, problem solving, translating problems into goals and developing action plans, strategies for coming up with useful goals and action items, and monitoring progress.
Social Support
Authors: Mohr David C.
Published: August 2015

Chapter 6 discusses social support, including its benefits, types of support (emotional, information, practical, belonging), identifying a social support network, things to consider in developing and using support, and problems that may occur when support needs are met (decreasing isolation, asking for support, your ability to provide care and support to others).
Module 5: Pain Management
Authors: Mohr David C.
Published: August 2015

This chapter describes an optional treatment module on pain management. It explores sources of pain, types of MS pain (acute pain, chronic pain), self-monitoring using a pain diary, relaxation and pain, tools for coping with pain.
ALMA imaging of SDP.81 – II. A pixelated reconstruction of the CO emission lines
Authors: Rybak M. , Vegetti S. , McKean J. P. , Andreani P. , White S. D. M.
Published: August 2015

We present a sub-100 pc-scale analysis of the CO molecular gas emission and kinematics of the gravitational lens system SDP.81 at redshift 3.042 using Atacama Large Millimetre/submillimetre Array (ALMA) science verification data and a visibility-plane lens reconstruction technique. We find clear evidence for an excitation-dependent structure in the unlensed molecular gas distribution, with emission in CO (5–4) being significantly more diffuse and structured than in CO (8–7). The intrinsic line luminosity ratio is r8–7/5−4 = 0.30 ± 0.04, which is consistent with other low-excitation starbursts at z ∼ 3. An analysis of the velocity fields shows evidence for a star-forming disc with multiple velocity components that is consistent with a merger/post-coalescence merger scenario, and a dynamical mass of M(<1.56 kpc) = 1.6 ± 0.6 × 1010 M⊙. Source reconstructions from ALMA and the Hubble Space Telescope show that the stellar component is offset from the molecular gas and dust components. Together with Karl G. Jansky Very Large Array CO (1–0) data, they provide corroborative evidence for a complex ∼2 kpc-scale starburst that is embedded within a larger ∼15 kpc structure.
‘Super' or just ‘above average'? Supershedders and the transmission of
Escherichia coli
O157:H7 among feedlot cattle
Authors: Spencer Simon E. F. , Besser Thomas E. , Cobbold Rowland N. , French Nigel P.
Published: August 2015

Supershedders have been suggested to be major drivers of transmission of
Escherichia coli
O157:H7 (
E. coli
O157:H7) among cattle in feedlot environments, despite our relatively limited knowledge of the processes that govern periods of high shedding within an individual animal. In this study, we attempt a data-driven approach, estimating the key characteristics of high shedding behaviour, including effects on transmission to other animals, directly from a study of natural
E. coli
O157:H7 infection of cattle in a research feedlot, in order to develop an evidence-based definition of supershedding. In contrast to the hypothesized role of supershedders, we found that high shedding individuals only modestly increased the risk of transmission: individuals shedding over 10
3
cfu g
−1
faeces were estimated to pose a risk of transmission only 2.45 times greater than those shedding below that level. The data suggested that shedding above 10
3
cfu g
−1
faeces was the most appropriate definition of supershedding behaviour and under this definition supershedding was surprisingly common, with an estimated prevalence of 31.3% in colonized individuals. We found no evidence that environmental contamination by faeces of shedding cattle contributed to transmission over timescales longer than 3 days and preliminary evidence that higher stocking density increased the risk of transmission.
How body torque and Strouhal number change with swimming speed and developmental stage in larval zebrafish
Authors: van Leeuwen Johan L. , Voesenek Cees J. , Müller Ulrike K.
Published: August 2015

Small undulatory swimmers such as larval zebrafish experience both inertial and viscous forces, the relative importance of which is indicated by the Reynolds number (Re).Reis proportional to swimming speed (vswim) and body length; faster swimming reduces the relative effect of viscous forces. Compared with adults, larval fish experience relatively high (mainly viscous) drag during cyclic swimming. To enhance thrust to an equally high level, they must employ a high product of tail-beat frequency and (peak-to-peak) amplitudefAtail, resulting in a relatively highfAtail/vswimratio (Strouhal number, St), and implying relatively high lateral momentum shedding and low propulsive efficiency. Using kinematic and inverse-dynamics analyses, we studied cyclic swimming of larval zebrafish aged 2–5 days post-fertilization (dpf). Larvae at 4–5 dpf reach higherf(95 Hz) andAtail(2.4 mm) than at 2 dpf (80 Hz, 1.8 mm), increasing swimming speed andRe, indicating increasing muscle powers. AsReincreases (60 → 1400), St (2.5 → 0.72) decreases nonlinearly towards values of large swimmers (0.2–0.6), indicating increased propulsive efficiency withvswimand age. Swimming at high St is associated with high-amplitude body torques and rotations. Low propulsive efficiencies and large yawing amplitudes are unavoidable physical constraints for small undulatory swimmers.
Lutibacter holmesii sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from the sea urchin Strongylocentrotus intermedius, and emended description of the genus Lutibacter
Authors: Nedashkovskaya Olga I. , Van Trappen Stefanie , Zhukova Natalia V. , De Vos Paul
Published: August 2015

Seven Gram-staining-negative, strictly aerobic, pale-yellow-pigmented, rod-shaped and non-motile strains were isolated from the sea urchin Strongylocentrotus intermedius collected from Troitsa Bay, Sea of Japan. Phylogenetic analyses based on 16S rRNA gene sequences showed that these isolates were affiliated with the family Flavobacteriaceae. The novel isolates showed 99.9–100 % 16S rRNA gene sequence similarity to each other and were closely related to the type strains of the recognized members of the genus Lutibacter with sequence similarities of 95.8–98.4 %. The G+C content of the genomic DNA was 35–36 mol%. DNA–DNA relatedness among the sea urchin isolates was 95–99 % and between strain KMM 6277T and its most closely related type strains, Lutibacter agarilyticus KCTC 23842T and Lutibacter litoralis JCM 13034T, was 38 and 27 %, respectively. The prevalent fatty acids were iso-C15 : 0, anteiso-C15 : 0, summed feature 3 (comprising iso-C15 : 0 2-OH and/or C16 : 1 ω7c fatty acids), iso-C15 : 1 and C15 : 0. The polar lipid profile was composed of the phosphatidylethanolamine, one unknown aminolipid and one unknown lipid. The main respiratory isoprenoid quinone was MK-6.The results of phylogenetic, phenotypic and genotypic analyses indicated that the novel strains represent a novel species within the genus Lutibacter, for which the name Lutibacter holmesii sp. nov. is proposed. The type strain is KMM 6277T ( = CCUG 62221T = LMG 26737T).
Crowdsourcing: Spatial clustering of low-affinity binding sites amplifiesin vivotranscription factor occupancy
Authors: Malin Justin , Ezer Daphne , Ma Xiaoyan , Mount Steve , Karathia Hiren , Park Seung Gu , Adryan Boris , Hannenhalli Sridhar
Published: August 2015

To predictin vivooccupancy of a transcription factor (TF), current models consider only the immediate genomic context of a putative binding site (BS) – impact of the site’s spatial chromatin context is not known. Using clusters of spatially proximal enhancers, or archipelagos, and DNase footprints to quantify TF occupancy, we report for the first time an emergent group-level effect on occupancy, whereby BS within an archipelago experience greaterin vivooccupancy than comparable BS outside archipelagos, i.e. BS not in spatial proximity with other homotypic BS. This occupancy boost is tissue-specific and scales robustly with the total number of BS, or enhancers, for the TF in the archipelago. Interestingly, enhancers within an archipelago are non-uniformly impacted by the occupancy boost; specifically, archipelago enhancers that are enriched for BS corresponding to degenerate motifs exhibit the greatest occupancy boost, as well as the highest overall accessibility, evolutionary selection, and expression at neighboring gene loci. Strikingly, archipelago-wide activity scales with expression of TFs with degenerate, but not specific, motifs. We explain these results through biophysical modelling, which suggests that spatially proximal homotypic BS facilitate TF diffusion, and induce boosts in local TF concentration and occupancy. Together, we demonstrate for the first time cooperativity among genomically distal homotypic BS that is contingent upon their spatial proximity, consistent with a TF diffusion model. Through leveraging of three-dimensional chromatin structure and TF availability, weak archipelago binding sitescrowdsourcetheir occupancy as well as context specificity, with coordinated switch-like effect on overall archipelago activity.
Hebbian Wiring Plasticity Generates Efficient Network Structures for Robust Inference with Synaptic Weight Plasticity
Authors: Hiratani Naoki , Fukai Tomoki
Published: August 2015

In the adult mammalian cortex, a small fraction of spines are created and eliminated every day, and the resultant synaptic connection structure is highly nonrandom, even in local circuits. However, it remains unknown whether a particular synaptic connection structure is functionally advantageous in local circuits, and why creation and elimination of synaptic connections is necessary in addition to rich synaptic weight plasticity. To answer these questions, we studied an inference task model through theoretical and numerical analyses. We demonstrate that a robustly beneficial network structure naturally emerges by combining Hebbian-type synaptic weight plasticity and wiring plasticity. Especially in a sparsely connected network, wiring plasticity achieves reliable computation by enabling efficient information transmission. Furthermore, the proposed rule reproduces experimental observed correlation between spine dynamics and task performance.
Gap gene regulatory dynamics evolve along a genotype network
Authors: Crombach Anton , Wotton Karl R. , Jiménez-Guri Eva , Jaeger Johannes
Published: August 2015

Developmental gene networks implement the dynamic regulatory mechanisms that pattern and shape the organism. Over evolutionary time, the wiring of these networks changes, yet the patterning outcome is often preserved, a phenomenon known as “system drift”. System drift is illustrated by the gap gene network—involved in segmental patterning—in dipteran insects. In the classic model organismDrosophila melanogasterand the non-model scuttle flyMegaselia abdita, early activation and placement of gap gene expression domains show significant quantitative differences, yet the final patterning output of the system is essentially identical in both species. In this detailed modeling analysis of system drift, we use gene circuits which are fit to quantitative gap gene expression data inM. abditaand compare them to an equivalent set of models fromD. melanogaster.The results of this comparative analysis show precisely how compensatory regulatory mechanisms achieve equivalent final patterns in both species. We discuss the larger implications of the work in terms of “genotype networks” and the ways in which the structure of regulatory networks can influence patterns of evolutionary change (evolvability).