bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐profile wideband unidirectional patch antenna with improved feed structure
Authors: He Kai , Gong Shuxi , Gao Feng
Published: February 2015

A low‐profile wideband unidirectional patch antenna excited by a tapered staircase‐shaped feed strip with a tuning patch is presented. A prototype with a height of 17 mm (0.156λ) was studied. The results show that an impedance bandwidth of 86.2% for |S11| < − 10 dB from 1.57 to 3.95 GHz was achieved. Stable and symmetric unidirectional radiation patterns, a low cross‐polarisation level, low back radiation and an antenna gain ranging from 6.2 to 9.7 dBi was obtained over the operating band.
Remote light source for silicon photonic transceivers in mobile fronthaul applications
Authors: Giorgi L. , D'Errico A. , Presi M. , Ciaramella E. , Testa F.
Published: February 2015

The design and experimental characterisation of a depolarised light source for feeding a remote transceiver based on silicon photonics are presented. Since the transceiver only works in TE mode, the source is designed to deliver, over up to 10 km standard single‐mode fibre links, a continuous‐wave light with almost constant power along this polarisation direction, whatever be the random polarisation rotation because of the fibre link. The depolarised light source is realised by combining the output of two independent distributed feedback lasers, having orthogonal polarisation and controlled frequency difference. The transmission performance and stability of the remote light source are successfully tested.
Dimension reduction method for probabilistic power flow calculation
Authors: Xiao Qing
Published: February 2015

In this study, the probabilistic power flow (PPF) problem is modelled as a multiple integral with an implicit integrand. A detailed discussion is given about the dimension reduction (DR) method for solving PPF. To accommodate the dependency of the input random variables, Nataf transformation is introduced to map PPF problems in the independent standard normal space. Emphasis is put on the computational burden of DR method. Based on Taylor expansion, a deep sight is given in the residual error of univariate DR (UDR) method. Using the first four standardised central moments from UDR method, the generalised lambda distribution is employed to represent the probability distribution of the output variable. Finally, an IEEE‐118 case is performed to check the proposed method.
Enhancing the performance of transmission line directional relaying, fault classification and fault location schemes using fuzzy inference system
Authors: Yadav Anamika , Swetapadma Aleena
Published: February 2015

This study aims to improve the performance of transmission line directional relaying, fault classification and fault location schemes using fuzzy system. Three separate fuzzy inference system are designed for complete protection scheme for transmission line. The proposed technique is able to accurately detect the fault (both forward and reverse), locate and also identify the faulty phase(s) involved in all ten types of shunt faults that may occur in a transmission line under different fault inception angle, fault resistances and fault location. The proposed method needs current and voltage measurements available at the relay location and can perform the fault detection and classification in about a half‐cycle time. The proposed fuzzy logic based relay has less computation complexity and is better than other AI based methods such as artificial neural network, support vector machine, and decision tree (DT) etc. which require training. The percentage error in fault location is within 1 km for most of the cases. Fault location scheme has been validated using χ2 test with 5% level of significance. Proposed scheme is a setting free method and is suitable for wide range of parameters, fault detection time is less than half cycle and relay does not show any reaching mal‐operation so it is reliable, accurate and secure.
Closed‐loop control system for an improved hybrid flow controller and its comparison with some hybrid devices
Authors: Hosseinzadeh Soreshjani Mohsen , Kargar Abbas , Nabavi Niaki Sayed Ali
Published: February 2015

An improved configuration of the hybrid flow controller (HFC) is introduced to continuously adjust the power flow. In this configuration, a thyristor‐controlled series capacitance (TCSC) is added to the conventional HFC to provide continuous variation in the HFC reactance. Moreover, simple closed‐loop control methods are designed by considering all the practical constraints of TCSC for this improved HFC (IHFC) and another hybrid arrangement, which is called hybrid power flow controller. Furthermore, to compare and highlight features of the IHFC, simulation results of the designed controllers are carried out in different operating conditions and disturbances. This study also provides a quantitative comparison of various hybrid flexible AC transmission system devices.
Mode-shape-based mass detection scheme using mechanically diverse, indirectly coupled microresonator arrays
Authors: Glean Aldo A. , Judge John A. , Vignola Joseph F. , Ryan Teresa J.
Published: February 2015

We explore vibration localization in arrays of microresonators used for ultrasensitive mass detection and describe an algorithm for identifying the location and amount of added mass using measurements of a vibration mode of the system. For a set of sensing elements coupled through a common shuttle mass, the inter-element coupling is shown to be proportional to the ratio of the element masses to the shuttle mass and to vary with the frequency mistuning between any two sensing elements. When any two elements have sufficiently similar frequencies, mass adsorption on one element can result in measurable changes to multiple modes of the system. We describe the effects on system frequencies and mode shapes due to added mass, in terms of mass ratio and frequency spacing. In cases in which modes are not fully localized, frequency-shift-based mass detection methods may give ambiguous results. The mode-shape-based detection algorithm presented uses a single measured mode shape and corresponding natural frequency to identify the location and amount of added mass. Mass detection in the presence of measurement noise is numerically simulated using a ten element sensor array. The accuracy of the detection scheme is shown to depend on the amplitude with which each element vibrates in the chosen mode.
The suppression effect of external magnetic field on the high-power microwave window multipactor phenomenon
Authors: Zhang Xue , Wang Yong , Fan Junjie
Published: February 2015

To suppress the surface multipactor phenomenon and improve the transmitting power of the high-power microwave window, the application of external magnetic fields is theoretically analyzed and simulated. A Monte Carlo algorithm is used to track the secondary electron trajectories and study the multipactor scenario on the surface of a cylinder window. It is confirmed that over-resonant magnetic fields (an external magnetic field whose magnitude is slightly greater than that of a resonant magnetic field) will generate a compensating trajectory and collision, which can suppress the secondary electron avalanche. The optimal value of this external magnetic field that will avoid the multipactor phenomenon on cylinder windows is discussed.
Suppressing sampling noise in linear and two-dimensional spectral simulations
Authors: Kruiger Johannes F. , van der Vegte Cornelis P. , Jansen Thomas L. C.
Published: February 2015

We examine the problem of sampling noise encountered in time-domain simulations of linear and two-dimensional spectroscopies. A new adaptive apodization scheme based on physical arguments is devised for suppressing the noise in order to allow reducing the number of used disorder realisations, but introducing only a minimum of spectral aberrations and thus allowing a potential speed-up of these types of simulations. First, the method is demonstrated on an artificial dimer system, where the effect on slope analysis, typically used to study spectral dynamics, is analysed. It is, furthermore, tested on the simulated two-dimensional infrared spectra in the amide I region of the protein lysozyme. The cross polarisation component is investigated, particularly sensitive to sampling noise, because it relies on cancelling of the dominant diagonal spectral contributions. In all these cases, the adaptive apodization scheme is found to give more accurate results than the commonly used lifetime apodization scheme and in most cases better than the gaussian apodization scheme.
Partial differential equations from integrable vertex models
Authors: Galleas W.
Published: February 2015

In this work, we propose a mechanism for converting the spectral problem of vertex models transfer matrices into the solution of certain linear partial differential equations. This mechanism is illustrated for the Uq[sl̂(2)] invariant six-vertex model, and the resulting partial differential equation is studied for particular values of the lattice length.
Modeling electron emission and surface effects from diamond cathodes
Authors: Dimitrov D. A. , Smithe D. , Cary J. R. , Ben-Zvi I. , Rao T. , Smedley J. , Wang E.
Published: February 2015

We developed modeling capabilities, within the Vorpal particle-in-cell code, for three-dimensional simulations of surface effects and electron emission from semiconductor photocathodes. They include calculation of emission probabilities using general, piece-wise continuous, space-time dependent surface potentials, effective mass, and band bending field effects. We applied these models, in combination with previously implemented capabilities for modeling charge generation and transport in diamond, to investigate the emission dependence on applied electric field in the range from approximately 2 MV/m to 17 MV/m along the [100] direction. The simulation results were compared to experimental data. For the considered parameter regime, conservation of transverse electron momentum (in the plane of the emission surface) allows direct emission from only two (parallel to [100]) of the six equivalent lowest conduction band valleys. When the electron affinity χ is the only parameter varied in the simulations, the value χ = 0.31 eV leads to overall qualitative agreement with the probability of emission deduced from experiments. Including band bending in the simulations improves the agreement with the experimental data, particularly at low applied fields, but not significantly. Using surface potentials with different profiles further allows us to investigate the emission as a function of potential barrier height, width, and vacuum level position. However, adding surface patches with different levels of hydrogenation, modeled with position-dependent electron affinity, leads to the closest agreement with the experimental data.
Electrical and terahertz magnetospectroscopy studies of laser-patterned micro- and nanostructures on InAs-based heterostructures
Authors: Chiatti O. , Buchholz S. S. , Heyn Ch. , Hansen W. , Pakmehr M. , McCombe B. D. , Fischer S. F.
Published: February 2015

Nanostructures fabricated from narrow-gap semiconductors with strong spin-orbit interaction (SOI), such as InAs, can be used to filter momentum modes of electrons and offer the possibility to create and detect spin-polarized currents entirely by electric fields. Here, we present magnetotransport and THz magnetospectroscopy investigations of Hall-bars with back-gates made from in InGaAs/InAlAs quantum well structures with a strained 4 nm InAs-inserted channel. The two-dimensional electron gas is at 53 nm depth and has a carrier density of about 6 × 1011 cm−2 and mobility of about 2 × 105 cm2/Vs, after illumination. Electrical and THz optical transport measurements at low temperatures and in high magnetic fields reveal an effective mass of 0.038m0 and an anisotropic g-factor of up to 20, larger than for bulk InAs or InAs-based heterostructures. We demonstrate that quasi-one-dimensional channels can be formed by micro-laser lithography. The population of subbands is controlled by in-plane gates. Contrary to previous reports, symmetric and asymmetric in-plane gate voltages applied to quasi-one dimensional channels did not show indications of SOI-induced anomalies in the conductance.
Indium tin oxide nanowires as hyperbolic metamaterials for near-field radiative heat transfer
Authors: Chang Jui-Yung , Basu Soumyadipta , Wang Liping
Published: February 2015

We investigate near-field radiative heat transfer between Indium Tin Oxide (ITO) nanowire arrays which behave as type 1 and 2 hyperbolic metamaterials. Using spatial dispersion dependent effective medium theory to model the dielectric function of the nanowires, the impact of filling fraction on the heat transfer is analyzed. Depending on the filling fraction, it is possible to achieve both types of hyperbolic modes. At 150 nm vacuum gap, the heat transfer between the nanowires with 0.5 filling fraction can be 11 times higher than that between two bulk ITOs. For vacuum gaps less than 150 nm the heat transfer increases as the filling fraction decreases. Results obtained from this study will facilitate applications of ITO nanowires as hyperbolic metamaterials for energy systems.
Coupled domain wall oscillations in magnetic cylindrical nanowires
Authors: Murapaka Chandrasekhar , Goolaup S. , Purnama I. , Lew W. S.
Published: February 2015

We report on transverse domain wall (DW) dynamics in two closely spaced cylindrical nanowires. The magnetostatically coupled DWs are shown to undergo an intrinsic oscillatory motion along the nanowire length in addition to their default rotational motion. In the absence of external forces, the amplitude of the DW oscillation is governed by the change in the frequency of the DW rotation. It is possible to sustain the DW oscillations by applying spin-polarized current to the nanowires to balance the repulsive magnetostatic coupling. The current density required to sustain the DW oscillation is found to be in the order of 105 A/cm2. Morover, our analysis of the oscillation reveals that the DWs in cylindrical nanowires possess a finite mass.
Dependence of domain structure on applied field direction in stacked media
Authors: Tomiyama N. , Ebata K. , Sugita R.
Published: February 2015

Domain structure of stacked media demagnetized with perpendicular or in-plane demagnetization field is investigated using MFM. For a demagnetized medium (sample A), the domain size is approximately 50 nm regardless of demagnetization field direction, while the contrast of the MFM image for the in-plane demagnetized sample is lower than that for the perpendicularly demagnetized sample. The domain of sample B where the cap layer was etched from the sample A is similar to that of the sample A in case of perpendicular demagnetization, which shows the domains of the cap and granular layers are integrated. Meanwhile, in case of in-plane demagnetization, the domain of the sample B is hardly observed, which suggests the domains of the cap and granular layers of the sample A are not integrated, and it is probable that the sub-domain structure is formed in the cap layer. The domain of sample C demagnetized in-plane after etching the cap layer from the stacked medium is hardly observed like the sample B, which shows that the domain of the granular layer of the sample A is not affected by the cap layer.
Extraordinary Hall effect based magnetic logic applications
Authors: Liu T. , Lacour D. , Montaigne F. , Le Gall S. , Hehn M. , Hauet T.
Published: February 2015

Extraordinary Hall Effect (EHE) based original concepts of a reconfigurable logic gate and a multi-bit logic comparator are presented. They exploit the EHE voltage that develops on cross cells connected in series that has no size limitation down to the nanometer scale. Experimental demonstrations are performed on both micro- and nanometer lateral size crosses made of ferrimagnetic TbCo alloy. The simplicity of the device architecture and its robustness make it advantageous when compared with existing systems.
Quantification of ordering at a solid-liquid interface using plasmon electron energy loss spectroscopy
Authors: Gandman Maria , Kauffmann Yaron , Kaplan Wayne D.
Published: February 2015

We present an in situ electron energy loss spectroscopy (EELS) study of ordering of liquid Al at various Al-Al2O3 interfaces. This technique utilizes precise measurements of the shifts in bulk plasmon resonance and their sensitivity to the valence electron density. Plasmon EELS combined with high resolution transmission electron microscopy provides information regarding the chemical composition in liquid Al at Al-Al2O3 interfaces. Preferential oxygen segregation to the (0006) Al2O3 plane was verified, and the (101¯2) Al2O3 plane was found to contain the lowest amount of segregated species.
Optoelectronically probing the density of nanowire surface trap states to the single state limit
Authors: Dan Yaping
Published: February 2015

Surface trap states play a dominant role in the optoelectronic properties of nanoscale devices. Understanding the surface trap states allows us to properly engineer the device surfaces for better performance. But characterization of surface trap states at nanoscale has been a formidable challenge using the traditional capacitive techniques. Here, we demonstrate a simple but powerful optoelectronic method to probe the density of nanowire surface trap states to the single state limit. In this method, we choose to tune the quasi-Fermi level across the bandgap of a silicon nanowire photoconductor, allowing for capture and emission of photogenerated charge carriers by surface trap states. The experimental data show that the energy density of nanowire surface trap states is in a range from 109 cm−2/eV at deep levels to 1012 cm−2/eV near the conduction band edge. This optoelectronic method allows us to conveniently probe trap states of ultra-scaled nano/quantum devices at extremely high precision.
The Emergence of iBorder: Bordering Bodies, Networks, and Machines
Authors: Pötzsch Holger
Published: February 2015

This paper scrutinizes the interrelation between technology and processes of bordering. In particular, it addresses the ways through which biometrics, dataveillance, predictive analytics, and robotics enlist the human body, networks, and human–machine assemblages in practices of inclusion and exclusion at the contemporary dislocated and ‘smart’ border. Through a description of the sociotechnical apparatuses underlying biometric, algorithmic, and automated border work, the paper develops the term iBorder, and connects its specific affordances to an emergent late-modern regime of security. With reference to the notion of cultural technique, the paper argues that contemporary technologically facilitated practices of bordering coconstitute, rather than merely process, contingent subjectivities and frames for practice.
Optimising the interrelationship between intake per cow and intake per hectare
Authors: Romera Alvaro J. , Doole Graeme J.
Published: February 2015

Production and profit in grazed systems remain inherently constrained by the fundamental trade-off between maximising individual herbage intake and pasture utilisation. The primary objective of this paper is to investigate the trade-off between herbage intake per cow and intake per hectare, from the perspective of economic optimisation, for an intensive pasture-based dairy farm in New Zealand (NZ). A detailed optimisation model of a dairy farm is applied, to allow the complex animal–plant–supplement dynamics underlying this relationship to be explicitly considered. Model output confirmed the existence of the fundamental inverse relationship between individual cow intake and herbage utilisation, which arises from the underlying biophysical dynamics within a grazing system, in the context of pasture-based NZ dairy farms. Results indicated that profitable management relies on increasing total pasture eaten (grazing plus pasture silage harvested on farm) through the use of a relatively high stocking rate and moderate levels of pasture intake per cow. Indeed, for 450 kg liveweight cows, optimal pasture intake per cow is 5 t dry matter (DM) per cow for per hectare intakes of 12–16 t DM/ha and 4.5 t DM/cow for a per hectare intake of 17 t DM/ha. Thus, a goal to maximise both individual intake and herbage utilisation in grazing systems is misinformed; it is the latter that is principally important to farm profit. Indeed, seeking to maximise both simultaneously is not possible, and trying to maximise individual intake can impose an enormous cost. However, while high herbage utilisation increases profit, this can also be associated with greater nutrient leaching, reinforcing the importance of considering the environmental impacts of grazing management.
The catastrophe of meal eating
Authors: Forbes J. M. , Gregorini P.
Published: February 2015

Optimisation of feed intake is a major aim of pasture and range management for ruminants and understanding what influences feeding behaviour may play an important role in satisfying this aim. An obstacle to such understanding is the fact that feeding is a two-state variable (eating or not eating, albeit with changes in rate of eating during meals), whereas the likely influencing factors are mostly continuous variables. These include gut-fill, concentrations and rates of utilisation of nutrients and metabolites, and changes in nutrient demand due to growth, reproduction and environment, both climatic and social. Catastrophe theory deals mathematically with situations in which an outcome is discontinuous (e.g. eating or not eating) and influencing variables (‘control’ variables in terms of catastrophe theory) are continuously variable (e.g. physiological and environmental factors affecting feeding). We discuss models of feeding and develop an approach in which the Type 2 catastrophe, illustrated by the bifurcation or cusp diagram, is adapted to use negative feedbacks and capacity to handle food and nutrients as the two controlling factors. Ease of prehension, as expressed by rate of eating, is modelled, as are pauses within, as well as between, meals. Quantification has not yet been attempted and the approach is presented to stimulate new thinking about the modelling and prediction of feeding behaviour and meal dynamics.
Modelling preference and diet selection patterns by grazing ruminants: a development in a mechanistic model of a grazing dairy cow, MINDY
Authors: Gregorini P. , Villalba J. J. , Provenza F. D. , Beukes P. C. , Forbes J. M.
Published: February 2015

The work presented here represents additions to the mechanistic and dynamic model of a grazing dairy cow (MINDY). The additions include a module representing preference and selection, based on two theories, namely, post-ingestive feedback and discomfort. The model was evaluated by assessing its ability to simulate patterns of preference and selection in response to a variety of feeding management. The improvements detailed here enable a realistic simulation of patterns of food selection by grazing ruminants, based on a range of feeding situations from different studies with cattle and sheep. These simulations indicate that the concepts encoded in MINDY capture several of the underlying biological mechanisms that drive preferences and selective behaviour. Thus, simulations using MINDY allow prediction of daily and diurnal patterns of selection based on preference, derived from some post-ingestive feedbacks and total discomfort. Estimates of herbage intake and parallel measurements of ingestive behaviour, rumen function and metabolism in grazing ruminants pose experimental and technical difficulties, and matching these processes to animal preference and selective behaviour is a greater challenge. As a consequence, advances in knowledge of foraging behaviour and dietary choice are slow and costly. On completion of more thorough testing, MINDY can be used as a tool for exploratory mechanistic research, to design and organise experimental programs to address a range of factors that control intake and its ecology, helping advance knowledge faster and at a low cost.
Spatial and temporal domains of scale of grazing cattle
Authors: Larson-Praplan S. , George M. R. , Buckhouse J. C. , Laca E. A.
Published: February 2015

Spatio-temporal patterns of cattle grazing were studied in four annual grassland pastures in California, differing mainly in tree canopy cover. Cows were equipped with global positioning collars that recorded position, temperature and head movements at 5-min intervals during 6 days in each of four seasons repeated during 2 years. The time animals took to traverse areas of varying diameter revealed patches of 6–9-m diameter in the pastures with low, and 18–21-m diameter in the pastures with high tree canopy cover. In agreement with the current model, crookedness of cow paths had two distinct domains. Within distances of 0–40 m, paths were relatively straight and similar, but from 40 to 200 m, they became increasingly tortuous. Correlation of sequential turning angles identified patches of movement with diameters between 40 and 100 m, which correspond to the ‘patch’ level of grazing within grazing sites. Seasonal changes in meal patterns were consistent with changes in temperature and forage quality and interacted with the distribution of shade. Thus, spatial distribution of grazing and temporal distribution of meals were inextricably linked. Low forage quality and high temperatures in summer resulted in highly concentrated grazing around trees. Conversely, winter and early spring forages of very high quality and low availability motivated more widely distributed grazing, with low proportion of areas being re-grazed. Resting sites acted as beginning and end of grazing bouts. We conclude that shade distribution can modulate meal start and duration.
Impacts of burrows and mounds formed by plateau rodents on plant species diversity on the Qinghai-Tibetan Plateau
Authors: Wu Ruixin , Chai Qi , Zhang Jianquan , Zhong Mengying , Liu Yuehua , Wei Xiaoting , Pan Duo , Shao Xinqing
Published: February 2015

The relationships among environmental factors, rodent activity disturbance and plant-community diversity were studied across four sites in a prefecture of the ‘Three-River-Source’ region of the Qinghai-Tibetan Plateau. It was found that burrow number and mound area had little impact on plant diversity indices, which were mainly affected by altitude, soil total P and pH. Altitude and mound area, especially mound area, can strongly affect the aboveground biomass and the vegetation cover of plants was mainly influenced by mound area. There was some evidence that moderate levels of disturbance by rodents could lead to the highest levels of plant diversity. These findings indicated that moderate levels of disturbance by rodents may be beneficial to grassland productivity and plant diversity. Understanding these impacts is vital for better rangeland management practices so that rodents should be controlled within a suitable range rather than being exterminated.
Effect of a grazing ban on restoring the degraded alpine meadows of Northern Tibet, China
Authors: Zhang W. N. , Ganjurjav H. , Liang Y. , Gao Q. Z. , Wan Y. F. , Li Y. , Baima Y. Z. , Xirao Z. M.
Published: February 2015

Banning of grazing is a widely used means of restoring degraded rangeland in China. However, little is known about the time required to restore degraded alpine meadows through the use of a grazing ban. Height and cover of individual plant species and total cover, herbage mass and root mass of each plot of a grazing ban and communal free-grazing alpine meadows in Northern Tibet were examined. Soil samples were also collected and total organic carbon, microbial biomass carbon, total phosphorus and ammonium nitrogen contents were measured. The results showed that both the level of plant species diversity and herbage mass were higher in areas of a grazing ban than in communal free-grazing land without a grazing ban. No significant differences in root mass and soil nutrient contents were observed. There was a higher plant species diversity and herbage mass in the early years of a grazing ban but there was a subsequent decline. It is suggested that some grazing after a grazing ban may be necessary according to the dynamics of ecosystem responses with time.
Mating behaviour in pygmy bluetongue lizards: do females ‘attract' male lizards?
Authors: Ebrahimi Mehregan , Godfrey Stephanie S. , Fenner Aaron L. , Bull C. Michael
Published: February 2015

Mating behaviour in lizards has been well studied, with most reports indicating that the male dominates in initiating the mating, characteristically displaying visually to attract partners. This strategy may be less successful in secretive species that remain in small areas around their refuge, infrequently encountering other conspecifics, like the endangered Australian pygmy bluetongue lizard (Tiliqua adelaidensis). Adult lizards of this species spend most of their time in or at the entrance of single-entrance vertical burrows, built by spiders, in patches of native grassland in South Australia. We filmed the behaviour of nine female lizards for 10 days in each month from October 2011 to February 2012. During filming in October, the austral spring, we observed 43 cases of females making moves away from their burrows, and back along the same path, in that month, that we did not observe among males, or among females in any other month. We observed 27 cases of males approaching female burrows, only in October and mostly along the paths previously taken by the females. Males attempted to mate, and were successful on five occasions. We describe the female movements and suggest that their function is to attract male mating partners.
Sex, citizenship and the state in Nigeria: Islam, Christianity and emergent struggles over intimacy
Authors: Obadare Ebenezer
Published: February 2015

In this article, the author uses the belligerence toward alternative sexualities in Nigeria as a point of departure for a critical appraisal of the terms of inclusion and exclusion in the country's body politic. This belligerence has thrown up a rare alliance of the state, religious leaders and the print media. Attributing this alliance to the postcolonial crisis over the functions of masculinisation and power, the author suggests that anti-gay resentment is a straw man for a ruling elite facing growing socio-economic pressure. This shunting-off of sexual ‘others’ from the terrain of public action has profound implications for the way modern Nigerian citizenship is understood.
Introduction: A mountain giving birth to a mouse? On the impact and legacy of Silvio Berlusconi in Italy
Authors: Albertazzi Daniele , Newell James L.
Published: February 2015

Love him or loathe him, Silvio Berlusconi is widely assumed to be Europe's most remarkable politician of recent decades, one who has not only affected the nature of electoral competition or the shape of the party system in Italy, but one who has influenced the country's political agenda to the extent that he himself and his role in politics have for long periods been the most important issues around which party competition has taken place.
How a catch–quota balancing system can go wrong: an evaluation of the species quota transformation provisions in the Icelandic multispecies demersal fishery
Authors: Woods Pamela J. , Holland Daniel S. , Marteinsdóttir Guðrún , Punt André E.
Published: February 2015

Implementation of single-species catch limits in multispecies individual quota systems is problematic because it may incentivize discarding behaviour when quotas for some species limit catch of jointly caught species. Since discarding may reduce economic benefits and bias stock assessments, mechanisms that reduce incentives to discard can be beneficial. However, these mechanisms may be detrimental in the long term if they also pose a risk of stock depletion, which can occur if they enable catch to persistently exceed the total allowable catch (TAC). This study uses a bioeconomic model to analyse potential negative consequences of species quota transformation provisions, using the Icelandic individual transferable quota system as a case study. These provisions allow quota of one species to be transformed into quota of another species at specified rates related to relative market value. The system reduces the degree that the TAC of any particular species constrains catch of other species. However, it also allows catches of some species to exceed TACs, possibly leading to stock depletion. We explore how these provisions may affect long-term sustainability of individual species and profitability of the fishery as a whole. We focus on the extreme case of perfect targeting (i.e. full control of catch composition) to increase intuition on the potential for adverse effects of this system. Various combinations of species profitability are examined to determine attributes of species that lead to greater vulnerability, as well as interactions in species utilization. Consequences of changing harvest control rules are explored, and information needed to monitor for unintended consequences of such a system in practice are discussed. Although the species transformation system is designed to increase economic efficiency, our results show that it could lead to depletion in some cases, and may make it difficult to achieve optimal management goals.
Steady-state pharmacokinetics of rilpivirine under different meal conditions in HIV-1-infected Ugandan adults
Authors: Lamorde Mohammed , Walimbwa Stephen , Byakika-Kibwika Pauline , Katwere Michael , Mukisa Lillian , Sempa Joseph B. , Else Laura , Back David J. , Khoo Saye H. , Merry Concepta
Published: February 2015

Objectives

To investigate the effect of food on the steady-state pharmacokinetics of rilpivirine when administered as a fixed-dose combination tablet containing tenofovir disoproxil fumarate, emtricitabine plus rilpivirine (TDF/FTC/RPV) in HIV-1-infected Ugandan patients.

Methods

This was an open-label, three-period, longitudinal pharmacokinetic study with patients serving as their own controls. Fifteen consenting and virologically suppressed HIV-1-infected adults were switched from an efavirenz-based regimen to TDF/FTC/RPV for 56 days. Enrolled patients underwent 24 h blood sampling with TDF/FTC/RPV dosing in the fasted state (day 42), with a low-fat meal (11 g of fat/353 kcal, day 49) and with a moderate-fat meal (19 g of fat/589 kcal, day 56; reference). A viral load assessment was performed on day 56.

Results

Rilpivirine AUC0–24 was significantly decreased by 16% (geometric mean ratio, 90% CI: 0.84, 0.73–0.96) during administration in the fasted state when compared with AUC0–24 during administration with a moderate-fat meal. Similarly, rilpivirine C24 was significantly decreased by 21% (0.79, 0.65–0.97) in the fasted state compared with a moderate-fat meal. Pharmacokinetic parameters were unchanged during administration with a low-fat meal, except for C24, which was significantly increased by 15% (1.15, 1.01–1.31) when compared with the moderate-fat meal. Rilpivirine Cmax was similar under the three meal conditions. Virological suppression was unchanged at the end of the study.

Conclusions

A food effect was observed for steady-state pharmacokinetic parameters of rilpivirine (AUC0–24 and C24) when TDF/FTC/RPV was administered in the fasted state compared with the moderate-fat meal. The TDF/FTC/RPV formulation can be administered with either a low-fat or moderate-fat meal.
Risk factors for nephrotoxicity onset associated with polymyxin B therapy
Authors: Dubrovskaya Yanina , Prasad Nishant , Lee Yuman , Esaian Diana , Figueroa Deborah A. , Tam Vincent H.
Published: February 2015

Objectives

Polymyxin B is an active agent against many MDR Gram-negative bacteria, but nephrotoxicity is a major hindrance to its widespread use. To guide its optimal use, we determined the risk factors for nephrotoxicity onset associated with polymyxin B.

Methods

In a multicentre, retrospective, cohort study, we evaluated adult patients with normal renal function who received ≥72 h of polymyxin B therapy. Pertinent information was retrieved from medical records; patients were followed for up to 30 days after therapy was started. The primary endpoint of this study was the onset of nephrotoxicity. A Cox proportional hazards model was used for analysis.

Results

A total of 192 patients (52.1% male, 67.7% Caucasian) were evaluated. The mean ± SD age, actual body weight (ABW) and daily dose by ABW were 68.3 ± 17.2 years, 71.5 ± 20.4 kg and 1.5 ± 0.5 mg/kg, respectively. The median duration of therapy was 9.5 days. The overall prevalence rate of nephrotoxicity was 45.8% and the median onset of nephrotoxicity was 9 days. Independent risk factors for the onset of nephrotoxicity included daily dose by ABW (HR = 1.73; P = 0.022), concurrent use of vancomycin (HR = 1.89; P = 0.005) and contrast media (HR = 1.79; P = 0.009). Nephrotoxicity was seen earlier in the high-risk group (P = 0.003).

Conclusions

Risk factors for nephrotoxicity onset associated with polymyxin B were identified. In conjunction with susceptibility and other pharmacokinetic/pharmacodynamic data, our results can be used to optimize treatment for MDR Gram-negative infections.
Century-long monitoring of solar irradiance and Earth's albedo using a stable scattering target in space
Authors: Judge Philip G. , Egeland Ricky
Published: February 2015

An inert sphere of a few metres diameter, placed in a special stable geosynchronous orbit in perpetuo, can be used for a variety of scientific experiments. Ground-based observations of such a sphere, ‘GeoSphere’, can resolve very difficult problems in measuring the long-term solar irradiance. GeoSphere measurements will also help us understand the evolution of Earth's albedo and climate over at least the next century.
Drying and Grinding Characteristics of Four‐Day‐Germinated and Crushed Wheat: A Novel Approach for Producing Sprouted Flour
Authors: Dziki Dariusz , Gawlik‐Dziki Urszula , Różyło Renata , Miś Antoni
Published: February 2015

The purpose of this study was to examine the drying and grinding characteristics of sprouted and crushed wheat. The four‐day‐germinated wheat kernels were crushed, dried, and ground in a micro hammer mill. The drying kinetics of sprouts were best described by the Page and two‐factor models. The crushing of wheat sprouts before drying decreased the drying time by about half. Sprouting and crushing of wheat sprouts have a significant influence on the grinding process, both on the particle size distribution and on the grinding energy requirements. It was observed that the ground sprouts showed significantly lower values of average particle size compared with the samples of sound kernels. Sprouting caused an increase in the amount of fine particles (<0.2 mm) and a decrease in the mass fraction of coarse particles (>1.0 mm). All values of grinding indices showed that sprouting and crushing significantly reduced the grinding energy requirements. Moreover, sprouting significantly increased the total phenolics content (from 26 to 31%) and antioxidant activity (from 33 to 72%) of wheat kernels. The results showed that sprouting and crushing of sprouts followed by their drying and grinding may provide a practical method for preparing sprouted flour.
Impaired Motor Competence in Children With Transplanted Liver
Authors: Almaas Runar , Jensen Unn , Loennecken Marianne C. , Tveter Anne T. , Sanengen Truls , Scholz Tim , Holm Inger
Published: February 2015

Objectives:

Although reduced cognitive function has been demonstrated after liver transplantation in children, few data are available concerning motor competence.

Methods:

Thirty‐five children ages 4 to 12 years were tested using Movement Assessment Battery for Children (M‐ABC) test at a median of 5.1 (3.9–6.9) years after liver transplantation and compared with reference material of healthy children.

Results:

Children with transplantation had worse M‐ABC score 8.0 (interquartile range 5.0–11.5), compared with healthy children 3.5 (1.0–6.0) (P < 0.0001). All of the subscores (manual dexterity [P < 0.0001], ball skills [P = 0.0037], and balance [P = 0.0032]) were significantly worse in the children with liver transplantation compared with the healthy reference group. Twenty‐nine percent of the children with liver transplantation had impaired motor competence, compared with 9% of a healthy reference group. Seventeen of the patients with transplantation were retested 1 year later, and 11 were tested 4 years later with no changes in total M‐ABC score. Ball skill competence was worse 4 years after first assessment (P = 0.013). For children with transplantation and cholestatic liver disease (n = 26), renal function was a significant predictor for total M‐ABC score (P = 0.018).

Conclusions:

Children with liver transplantation had impaired motor competence compared with healthy children. Ball skills developed adversely several years after liver transplantation, and motor competence did not improve with time after transplantation. Renal function was a significant predictor for motor competence in children with liver transplantation and cholestatic liver disease.
Increase of Serum γ‐Glutamyltransferase Associated With Development of Cirrhotic Cystic Fibrosis Liver Disease
Authors: Bodewes Frank A.J.A. , van der Doef Hubert P.J. , Houwen Roderick H.J. , Verkade Henkjan J.
Published: February 2015

Background:

Identification of patients at risk for developing cirrhotic cystic fibrosis liver disease (CCFLD) is essential for targeting potentially preventive treatment. We studied the evolution of serum liver enzymes and thrombocyte counts as predictors of CCFLD development.

Methods:

For this study, we defined the diagnosis of CCFLD as the combination of splenomegaly (on either physical examination or ultrasound scan) and macronodularity of the liver on ultrasound scan. We reviewed the medical records of 277 pediatric patients with CF for the diagnosis of CCFLD. In each patient with CCFLD, we reviewed serum liver enzymes and thrombocyte counts in the 2‐year period preceding the diagnosis of CCFLD. We compared these results with a non‐CCFLD control group (patients with CF older than 15 years with no reported signs or symptoms of CCFLD).

Results:

In the 2 years preceding the diagnosis, the γ‐glutamyltranspeptidase (GGT) levels of patients with CCFLD were significantly higher compared to non‐CCFLD controls (42 ± 5 vs 17 ± 2 U/L, respectively; P < 0.001). Corresponding aspartate aminotransferase and alanine aminotransferase levels did not significantly differ between patients with CCFLD and controls. The thrombocyte counts in patients with CCFLD were significantly lower than those in controls (252 ± 108 vs 320 ± 94 × 109 /L, respectively; P < 0.05). The predictive value for CCFLD of a single GGT measurement was low; however, for patients with CF with a mean GGT > 35 U/L, based on repeated measurements, the odds ratio for developing CCFLD was 39 (95% confidence interval 9–175, specificity was 95%, sensitivity was 64%, positive predictive value was 50%). For the thrombocytes, however, no reliable cutoff value could be identified.

Conclusions:

In pediatric patients with CF, a persistently high‐normal GGT is strongly associated with the diagnosis of CCFLD within 2 years. The prognostic value of a single GGT measurement is limited, but repeated GGT measurements may allow the identification of groups of patients at increased risk for CCFLD.
How spatial heterogeneity shapes multiscale biochemical reaction network dynamics
Authors: Pfaffelhuber Peter , Popovic Lea
Published: February 2015

Spatial heterogeneity in cells can be modelled using distinct compartments connected by molecular movement between them. In addition to movement, changes in the amount of molecules are due to biochemical reactions within compartments, often such that some molecular types fluctuate on a slower timescale than others. It is natural to ask the following questions: how sensitive is the dynamics of molecular types to their own spatial distribution, and how sensitive are they to the distribution of others? What conditions lead to effective homogeneity in biochemical dynamics despite heterogeneity in molecular distribution? What kind of spatial distribution is optimal from the point of view of some downstream product? Within a spatially heterogeneous multiscale model, we consider two notions of
dynamical homogeneity
(full homogeneity and homogeneity for the fast subsystem), and consider their implications under different timescales for the motility of molecules between compartments. We derive rigorous results for their dynamics and long-term behaviour, and illustrate them with examples of a shared pathway, Michaelis–Menten enzymatic kinetics and autoregulating feedbacks. Using stochastic averaging of fast fluctuations to their quasi-steady-state distribution, we obtain simple analytic results that significantly reduce the complexity and expedite simulation of stochastic compartment models of chemical reactions.
Cheaper faster drug development validated by the repositioning of drugs against neglected tropical diseases
Authors: Williams Kevin , Bilsland Elizabeth , Sparkes Andrew , Aubrey Wayne , Young Michael , Soldatova Larisa N. , De Grave Kurt , Ramon Jan , de Clare Michaela , Sirawaraporn Worachart , Oliver Stephen G. , King Ross D.
Published: February 2015

There is an urgent need to make drug discovery cheaper and faster. This will enable the development of treatments for diseases currently neglected for economic reasons, such as tropical and orphan diseases, and generally increase the supply of new drugs. Here, we report the Robot Scientist ‘Eve’ designed to make drug discovery more economical. A Robot Scientist is a laboratory automation system that uses artificial intelligence (AI) techniques to discover scientific knowledge through cycles of experimentation. Eve integrates and automates library-screening, hit-confirmation, and lead generation through cycles of quantitative structure activity relationship learning and testing. Using econometric modelling we demonstrate that the use of AI to select compounds economically outperforms standard drug screening. For further efficiency Eve uses a standardized form of assay to compute Boolean functions of compound properties. These assays can be quickly and cheaply engineered using synthetic biology, enabling more targets to be assayed for a given budget. Eve has repositioned several drugs against specific targets in parasites that cause tropical diseases. One validated discovery is that the anti-cancer compound TNP-470 is a potent inhibitor of dihydrofolate reductase from the malaria-causing parasite
Plasmodium vivax
.
Mechanical factors direct mouse aortic remodelling during early maturation
Authors: Le Victoria P. , Cheng Jeffrey K. , Kim Jungsil , Staiculescu Marius C. , Ficker Shawn W. , Sheth Saahil C. , Bhayani Siddharth A. , Mecham Robert P. , Yanagisawa Hiromi , Wagenseil Jessica E.
Published: February 2015

Numerous diseases have been linked to genetic mutations that lead to reduced amounts or disorganization of arterial elastic fibres. Previous work has shown that mice with reduced amounts of elastin (Eln+/−) are able to live a normal lifespan through cardiovascular adaptations, including changes in haemodynamic stresses, arterial geometry and arterial wall mechanics. It is not known if the timeline and presence of these adaptations are consistent in other mouse models of elastic fibre disease, such as those caused by the absence of fibulin-5 expression (Fbln5−/−). AdultFbln5−/−mice have disorganized elastic fibres, decreased arterial compliance and high blood pressure. We examined mechanical behaviour of the aorta inFbln5−/−mice through early maturation when the elastic fibres are being assembled. We found that the physiologic circumferential stretch, stress and modulus ofFbln5−/−aorta are maintained near wild-type levels. Constitutive modelling suggests that elastin contributions to the total stress are decreased, whereas collagen contributions are increased. Understanding how collagen fibre structure and mechanics compensate for defective elastic fibres to meet the mechanical requirements of the maturing aorta may help to better understand arterial remodelling in human elastinopathies.