bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanically reconfigurable antennas using an anisotropic carbon‐fibre composite ground
Authors: Mehdipour Aidin , Denidni Tayeb A. , Sebak Abdel‐R. , Trueman Christopher W. , Rosca Iosif D. , Hoa Suong V.
Published: August 2013

The authors present reconfigurable antennas based on anisotropic reinforced continuous carbon fibre composite (RCCFC) material. By the rotation of the anisotropic RCCFC ground plane, the current distribution can be changed to select a desirable mode of resonance and suppress unwanted modes. Hence, the RCCFC ground plane behaves as a mode filter in the proposed reconfigurable antennas. Several types of probe‐fed reconfigurable microstrip‐patch antennas are presented, including the RCCFC conductivity characteristics, the principle of reconfigurable operation and the simulated and measured performance. The outstanding mechanical strength of RCCFC materials along with the promising radiation characteristics of these reconfigurable antennas make them good candidates for radio cognitive and military applications.
Stability and dispersion analysis of higher order unconditionally stable three‐step locally one‐dimensional finite‐difference time‐domain method
Authors: Saxena Alok Kumar , Srivastava Kumar Vaibhav
Published: August 2013

Stability and dispersion analysis of higher‐order three‐step locally one‐dimensional (LOD) finite‐difference time‐domain (FDTD) method is presented here. This method uses higher order cell‐centred finite‐difference approximation for the spatial differential operator and second‐order finite difference approximation for the time differential operator. Unconditional stability of the higher‐order three‐step LOD‐FDTD method is analytically proven and numerically verified. Numerical results show improvement in the overall performance of higher‐order three‐step LOD‐FDTD method compared with that of second order. Also, the effects of the order of approximation, the time step and the mesh size on numerical dispersion are explained through analytical results and verified by simulation results.
Robust mask‐constrained linear array synthesis through an interval‐based particle SWARM optimisation
Authors: Manica Luca , Anselmi Nicola , Rocca Paolo , Massa Andrea
Published: August 2013

An innovative strategy for the robust design of linear antenna arrays is presented. Being the array elements characterised by tolerance errors, the synthesis is aimed at determining the intervals of values fitting the user‐defined mask constraints on the radiated power pattern. With reference to the upper and lower bounds of the power pattern analytically determined for given tolerances through interval analysis, the nominal excitations of the array elements are then optimised by means of a global stochastic optimiser suitably customised to deal with interval numbers. A set of numerical examples is reported to show the behaviour of the proposed method as well as to assess its potentials in dealing with the robust synthesis of pencil and shaped beams.
Synergy routing and dynamic spectrum allocation in multi‐hop cognitive radio networks
Authors: Zhu Xiaorong , Zhu Hongbo
Published: August 2013

To maximise spectrum efficiency and channel capacity, both unused (white) and underused (grey) spectral regions need to be exploited. The authors propose a distributed and localised algorithm for joint opportunistic routing and spectrum allocation for multi‐hop cognitive radio networks, and design a synergy routing, a utility‐based routing scheme that achieves synergistic cognitive radio benefits of overlay and underlay techniques and simultaneously maximises spectrum efficiency. The synergy routing opportunistically calculates the next hop according to the spectrum dynamics and residual energy of candidate relays and harvests the benefits from the cooperation of underlay and overlay spectrum. Simulation results indicate that our synergy prototype improves delay and throughput performance, while maintaining the autonomy and heterogeneity of individual underlay and overlay networks.
Modified electromagnetic microgenerator design for improved performance of low‐voltage energy‐harvesting systems
Authors: Dayal Rohan , Parsa Leila
Published: August 2013

The recent work in literature has shown the potential of energy harvesting as means to power wireless sensors. An energy harvester typically consists of a transducer and low‐power management circuits. However, current systems suffer from crude design methodology with no synergy between these two stages. In this work, the authors present two design modules of a modified electromagnetic microgenerator system, which aid in the performance of the associated power converter. Startup is a critical issue for such systems, since the transducer voltage is quite low (a few hundred millivolts AC). For the first design module, a thin piezoelectric strip is added to the electromagnetic microgenerator to provide the start‐up power for the converter system. The second module unifies the design of the input filter for the converter with the microgenerator. The microgenerator parasitics are utilised to satisfy the input filter requirements of the converter. Such an approach reduces the overall inductive losses in the system compared with other set‐ups reported in the literature. Both the microgenerator and the input filter are fabricated along with a suitable AC–DC boost converter using discrete components. Both simulation and experimental results are shown to demonstrate the start‐up capability of such a system and efficacy of the input filter design.
Minimum switching loss pulse width modulation for reduced power conversion loss in reactive power compensators
Authors: Siva Prasad Jaldanki Sreenivasa , Narayanan Gopalaratnam
Published: August 2013

Advanced bus‐clamping switching sequences, which employ an active vector twice in a subcycle, are used to reduce line current distortion and switching loss in a space vector modulated voltage source converter. This study evaluates minimum switching loss pulse width modulation (MSLPWM), which is a combination of such sequences, for static reactive power compensator (STATCOM) application. It is shown that MSLPWM results in a significant reduction in device loss over conventional space vector pulse width modulation. Experimental verification is presented at different power levels of up to 150 kVA.
Simple Kalman filter alternative: the multi‐fractional order estimator
Authors: Bell Jeffery W.
Published: August 2013

This study is an extension of a presentation given at the 2012 Radar Conference in Glasgow, UK entitled: Simple Disambiguation of Orthogonal Projection in Kalman's Filter Derivation. It is shown therein that Kalman misunderstood and consequently misapplied orthogonal projection in his derivation. Shocking analysis shows the Kalman filter (KF) to be truly optimum only in the absence of specific additive statistical measurement noise it is explicitly designed to filter out, rendering it a deterministic curve‐fitting algorithm. Also included are two examples demonstrating that the KF is not the universally asserted minimum variance linear unbiased estimator. These consequences are based on the newly introduced multi‐fractional order estimator (MFOE). Included herein are an additional background derivation and supplementary material as well as several new examples to better illustrate internal MFOE mechanics. Examples also show major problems in fine tuning the KF with a trade‐off between process and measurement noises. Finally, an example shows a very simple, automatic, seamless, smooth, optimal, non‐recursive second to third‐order estimator transition which successfully overcomes inadequate and complicated KF adaptivity, including thresholding, feedback, manoeuvre detection, deweighting matrices, manoeuvre probability, dual filter weighting, variable dimension models, state augmentation, multiple models, interactive multiple models, interactive acceleration compensation and so on.
Rapid, near‐optimal waveform adaptation: precompute and lookup via hash functions
Authors: Rossler Carl W. , Patton Lee Kenneth , Himed Braham
Published: August 2013

The authors propose a novel library‐based waveform adaptation method which allows rapid, near‐optimal, waveform adaptation for a broad set of applications. The authors refer to their method as precompute‐and‐lookup (PAL). In contrast to existing library‐based methods, which must evaluate each waveform in the library in order to determine the most suitable waveform, the authors’ method employs hash functions. With the authors’ method, the computational complexity of waveform adaptation is solely determined by the chosen hash function, and does not grow with library size. The authors apply PAL to the problem of waveform adaptation for target detection in the presence of additive coloured Gaussian noise under practical constraints. Monte Carlo simulations show that PAL is capable of producing near‐optimal waveforms.
Micro‐Doppler feature extraction for wideband imaging radar based on complex image orthogonal matching pursuit decomposition
Authors: Luo Ying , Zhang Qun , Qiu Chengwei , Li Song , Soon Yeo Tat
Published: August 2013

The micro‐Doppler (m‐D) features induced by targets with micro‐motions provide important information for automatic radar target recognition. In this study, the m‐D effect induced by rotational micro‐motion in wideband radar is analysed, and an algorithm for the extraction of these m‐D features is proposed. By making use of the amplitude and phase information of ‘range‐slow‐time image’, a dictionary with m‐D signal atoms is constructed in the complex image space. The orthogonal matching pursuit algorithm in vector space is then extended to the complex image space to decompose the range‐slow‐time image and to extract the m‐D features of the target. The proposed algorithm can extract the m‐D features in the presence of migration through range cells of micro‐motional scatterers, and can also work well when the sampling rate in slow‐time domain is lower than the Nyquist sampling rate. Simulations are given to validate the effectiveness and robustness of the proposed method.
Modelling and simulation of spatial‐temporal correlated K distributed clutter for coherent radar seeker
Authors: Yang Yong , Xiao Shun‐ping , Feng De‐jun , Zhang Wen‐ming
Published: August 2013

Modelling the clutter with accurate spatialtemporal correlation, amplitude statistical characteristic and coherence is significant to the evaluation of constant false alarm rate (CFAR) detection performance for coherent radar seeker in clutter. In this study, the authors propose a modelling method for spatialtemporal correlated coherent K distributed clutter. At first, with the assumption that clutter shape parameter is known, the authors estimate the scale parameter of K distributed clutter by calculating the clutter power of the range reference cell of CFAR detection according to the radar seeker operating circumstance. Then, they model the temporal correlated coherent K distributed clutter and spatial correlated coherent K distributed modulation component, respectively, by employing exogenous modelling method. The authors propose to modulate the temporal clutter with spatial modulation sequence to obtain spatialtemporal correlated coherent K distributed clutter for multiple range reference cells of CFAR detection. Finally, they show the validity of the proposed modelling method by simulation.
Ground moving target indication for high‐resolution wide‐swath synthetic aperture radar systems
Authors: Yang Taoli , Li Zhenfang , Suo Zhiyong , Bao Zheng
Published: August 2013

In this study, a new approach is presented to detect ground moving targets and estimate their motion parameters for high‐resolution and wide‐swath (HRWS) synthetic aperture radar (SAR) systems. First, the space‐time adaptive processing is adopted for clutter suppression, followed by the traditional SAR imaging and constant‐false‐alarm‐rate detection for obtaining the ambiguous images of ground moving targets. Then, the real targets can be distinguished from all the ambiguous ones based on the space relationship between ambiguous images. Finally, according to the shift amount of moving targets in azimuth, which can be obtained by utilising the range histories of moving targets, the motion parameter can be achieved. The spaceborne HRWS simulation data confirm the validity of the method.
Iterative acquisition method based on Grey code for weak global positioning system signal
Authors: Wang Jianhui , Ou Gang , Zhang Yonghu
Published: August 2013

For weak global positioning system signal, long coherent integration can improve the acquisition performance effectively, but the unknown data bits restrict the coherent integration interval within a data bit. Data bits estimation can extend coherent integration interval over multiple data bits with more Doppler frequency search bins. To lighten the calculation burden of data bit combinations searching, an iterative acquisition algorithm is presented based on ordering data bit combinations by Grey code. Modified block‐accumulating coherent integration over extended interval (BACIX) algorithm is also presented, which has linear complexity and better performance than BACIX algorithm.
Vehicle navigation filter designs using adaptive constraint‐filtering method
Authors: Chang Tsai‐Hsin , Hsiao Hsin‐Tai , Chen Chu‐Hui
Published: August 2013

The conventional filter requires that all the vehicle dynamics and noise processes are completely known. As a practical fact this is usually impossible. To deal with such a problem, the adaptive constraint‐filtering (ACF) method is proposed in this study. The CF method developed previously can accommodate the constraint in the filtering process for a non‐linear dynamic system. However, the assumption that the modelling noise and the sensor noise are known may not be practical. Here, the fuzzy innovation adaptive estimation approach is proposed to determine the window size, which is assumed constant in the classical adaptive scheme. To assess the performance of the proposed algorithm, the Monte Carlo method is adopted. The performance of the various filters, such as the Kalman filter (KF), the adaptive KF (AKF), the CF and the adaptive CF ACF are then compared. The simulation results show that the ACF method is evidently better than the other filters. From dynamic experimental results, it is shown that the proposed methodology yields a successful algorithm to manage the ill‐conditioned global positioning system positioning problem. The adaptation accuracy based on the proposed methodology is substantially improved.
Performance bounds of direction finding and its applications for multiple‐input multiple‐output radar
Authors: Chen Haowen , Li Xiang , Wang Hongqiang , Zhuang Zhaowen
Published: August 2013

In this study, the authors derive an explicit expression for Cramer–Rao lower bound (CRLB) on direction parameters with the antenna locations of a single point target in the far‐field scenario for multiple‐input multiple‐output (MIMO) radar, firstly. Since there are two unknown nuisance parameters (target radar cross section and interference‐plus‐noise strength), the authors use the concentrated CRLB to simplify the analytical computation. Then, the authors derive two sets of necessary and sufficient geometrical constraints for direction estimation with both bistatic and monostatic MIMO radars. Then, the authors consider the bounds on the asymptotic normalised mean‐square angular error (ANMSAE), which are useful measures in three‐dimensional bearing estimation problems. The authors derive the expressions for ANMSAE in both bistatic and monostatic MIMO radars, and discuss them in terms of the antenna locations. The authors then show that the uncoupled geometrical conditions are also sufficient to ensure that ANMSAE is independent of azimuth. Finally, the authors extend those conditions to obtain two sets of geometry constraints for bistatic and monostatic MIMO radars, respectively, such as some kinds of symmetry on the geometry, that ensure the optimal performance is isotropic, that is, the ANMSAE bounds are independent of all direction parameters. In numerical examples section, the authors give several representative antenna geometries to illustrate the derived antenna geometry strategy.
Non-Covalent Assembly of Maghemite-Multiwalled Carbon Nanotubes for Efficient Lead Removal from Aqueous Solution
Authors: Hasany Syed F. , Abdurahman N. H. , Sunarti A. R. , Kumar Anuj
Published: August 2013

Non-covalent assemblies of maghemite-embedded multiwalled carbon nanotubes (MWCNTs) were synthesised and characterised, and their applicability in the magnetic removal of PbII from aqueous solutions in batches was evaluated. The nanohybrids were prepared using a wet-chemical technique and characterised by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, zeta potential, vibrating sample magnetometer, and Brunauer–Emmett–Teller surface area measurements. Kinetics rate, adsorption isotherms, and effects of pH, contact time, adsorbent dosage, and agitation speed on PbII removal were studied. Results revealed maximum adsorption (~96 %, 24 ppm) was achieved in less than 2 h in a pH range of 6–7. Repeated adsorption–desorption cycles were conducted, which demonstrated that the nanohybrid could be used for prolonged cycles.
Soil phosphorus tests II: A comparison of soil test–crop response relationships for different soil tests and wheat
Authors: Speirs Simon D. , Scott Brendan J. , Moody Philip W. , Mason Sean D.
Published: August 2013

The performance of a wide range of soil phosphorus (P) testing methods that included established (Colwell-P, Olsen-P, BSES-P, and CaCl2-P) and more recently introduced methods (DGT-P and Mehlich 3-P) was evaluated on 164 archived soil samples corresponding to P fertiliser response experiments with wheat (Triticum aestivum) conducted in south-eastern Australia between 1968 and 2008. Soil test calibration relationships were developed for relative grain yield v. soil test using (i) all soils, (ii) Calcarosols, and (iii) all ‘soils other than Calcarosols’. Colwell-P and DGT-P calibration relationships were also derived for Calcarosols and Vertosols containing measureable CaCO3. The effect of soil P buffer capacity (measured as the single-point P buffer index corrected for Colwell-P, PBICol) on critical Colwell-P values was assessed by segregating field sites based on their PBICol class: very very low (15–35), very low (36–70), low (71–140), and moderate (141–280). All soil P tests, except Mehlich 3-P, showed moderate correlations with relative grain yield (R-value ≥0.43, P < 0.001) and DGT-P exhibited the largest R-value (0.55). Where soil test calibrations were derived for Calcarosols, Colwell-P had the smallest R-value (0.36), whereas DGT-P had an R-value of 0.66. For ‘soils other than Calcarosols’, R-values >0.45 decreased in the order: DGT-P (r = 0.55), Colwell-P (r = 0.49), CaCl2-P (r = 0.48), and BSES-P (r = 0.46). These results support the potential of DGT-P as a predictive soil P test, but indicate that Mehlich 3-P has little predictive use in these soils. Colwell-P had tighter critical confidence intervals than any other soil test for all calibrations except for soils classified as Calcarosols. Critical Colwell-P values, and confidence intervals, for the very very low, very low, and low P buffer capacity categories were within the range of other published data that indicate critical Colwell-P value increases as PBICol increases. Colwell-P is the current benchmark soil P test used in Australia and for the field trials in this study. With the exception of Calcarosols, no alternative soil P testing method was shown to provide a statistically superior prediction of response by wheat. Although having slightly lower R-values (i.e. <0.1 difference) for some calibration relationships, Colwell-P yielded tighter confidence intervals than did any of the other soil tests. The apparent advantage of DGT-P over Colwell-P on soils classified as Calcarosols was not due to the effects of calcium carbonate content of the analysed surface soils.
Deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus): mechanism of action and contraceptive efficacy
Authors: Wilson Michelle E. , Coulson Graeme , Shaw Geoff , Renfree Marilyn B.
Published: August 2013

Context
Fertility control offers a non-lethal management technique for iconic yet overabundant wildlife. Slow-release hormonal implants containing deslorelin show promise for managing free-ranging populations, particularly in peri-urban reserves, but most studies have been limited to captivity.

Aims
We investigated the efficacy and mechanism of deslorelin implants in free-ranging female eastern grey kangaroos (Macropus giganteus) under realistic management conditions.

Methods
We assigned females to a deslorelin (9.4 mg, n = 53) or placebo (n = 56) group at three peri-urban sites in Victoria, Australia, and monitored reproductive success for 3 years by observing young in the pouch. We tested the plasma LH response of control and treated females to exogenous GnRH, and compared the size of ovarian follicles between the two groups.

Key results
Deslorelin implants reduced fertility at all three sites. No deslorelin-treated females bred in Year 1 at Anglesea and Serendip versus 42% and 44% of control females respectively. At Plenty Gorge, 60% of deslorelin-treated females bred in Year 1 versus 100% of control females. In Year 2, between 11% and 39% of the treated females bred versus between 82% and 100% of control females at all sites. The contraceptive efficacy reduced by Year 3 when between 43% and 57% of the treated females bred versus between 85% and 100% of controls. A GnRH challenge elicited higher plasma LH concentrations in control than in treated females, and unlike untreated females, treated females lacked ovarian follicles >2 mm.

Conclusions
Deslorelin implants reduced fertility in free-ranging female eastern grey kangaroos over three successive breeding seasons. Chronic exposure to deslorelin desensitised the pituitary gland to GnRH and suppressed follicular development, but did not inhibit the development of a blastocyst, pregnancy or lactation in at least some females that had conceived before treatment.

Implications
Effective population management using deslorelin implants will require females to be re-treated on multiple occasions because the contraceptive effect lasts only a portion of their reproductive life. This would be practical only at sites where kangaroos are relatively easy to capture. The timing of treatment is also important in a species that undergoes embryonic diapause, particularly at sites providing high-quality habitat.
Assembler for de novo assembly of large genomes
Authors: Chu Te-Chin , Lu Chen-Hua , Liu Tsunglin , Lee Greg C. , Li Wen-Hsiung , Shih Arthur Chun-Chieh
Published: August 2013

Significance

Assembling a large genome faces three challenges: assembly quality, computer memory requirement, and execution time. Our developed assembler, JR-Assembler, uses (
a
) a strategy that selects good seeds for contig construction, (
b
) an extension strategy that uses whole sequencing reads to increase the chance to jump over repeats and to expedite extension, and (
c
) detecting misassemblies by remapping reads to assembled sequences. Compared with current assemblers, JR-Assembler achieves a better overall assembly quality, requires less execution time and requires, with one exception, less memory. The advantages of JR-Assembler in memory usage and execution time will increase slowly as the read length increases. Thus, contrary to the prevailing view, the extension approach seems superior to the de Bruijn graph approach.
DNorm: disease name normalization with pairwise learning to rank
Authors: Leaman Robert , Islamaj Doğan Rezarta , Lu Zhiyong
Published: August 2013

Motivation: Despite the central role of diseases in biomedical research, there have been much fewer attempts to automatically determine which diseases are mentioned in a text—the task of disease name normalization (DNorm)—compared with other normalization tasks in biomedical text mining research.

Methods: In this article we introduce the first machine learning approach for DNorm, using the NCBI disease corpus and the MEDIC vocabulary, which combines MeSH® and OMIM. Our method is a high-performing and mathematically principled framework for learning similarities between mentions and concept names directly from training data. The technique is based on pairwise learning to rank, which has not previously been applied to the normalization task but has proven successful in large optimization problems for information retrieval.

Results: We compare our method with several techniques based on lexical normalization and matching, MetaMap and Lucene. Our algorithm achieves 0.782 micro-averaged F-measure and 0.809 macro-averaged F-measure, an increase over the highest performing baseline method of 0.121 and 0.098, respectively.

Availability: The source code for DNorm is available at http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/DNorm, along with a web-based demonstration and links to the NCBI disease corpus. Results on PubMed abstracts are available in PubTator: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/PubTator

Contact:  zhiyong.lu@nih.gov
Beyond LATE: Estimation of the Average Treatment Effect with an Instrumental Variable
Authors: Aronow Peter M. , Carnegie Allison
Published: August 2013

Political scientists frequently use instrumental variables (IV) estimation to estimate the causal effect of an endogenous treatment variable. However, when the treatment effect is heterogeneous, this estimation strategy only recovers the local average treatment effect (LATE). The LATE is an average treatment effect (ATE) for a subset of the population: units that receive treatment if and only if they are induced by an exogenous IV. However, researchers may instead be interested in the ATE for the entire population of interest. In this article, we develop a simple reweighting method for estimating the ATE, shedding light on the identification challenge posed in moving from the LATE to the ATE. We apply our method to two published experiments in political science in which we demonstrate that the LATE has the potential to substantively differ from the ATE.
Analysis of Serum γ‐Glutamyl Transferase Levels in Neonatal Intensive Care Unit Patients
Authors: Hirfanoglu Ibrahim M. , Unal Sezin , Onal E. Esra , Beken Serdar , Turkyilmaz Canan , Pasaoglu Hatice , Koc Esin , Ergenekon Ebru , Atalay Yildiz
Published: August 2013

Objectives:

Gamma‐glutamyl transferase (GGT) is commonly measured in newborn infants as a sensitive liver function test; however, reference ranges are mostly based on early studies, including relatively small number of patients. The aim of this study was to emphasise recently changed GGT values because of changed newborns profile admitted to neonatal intensive care units (NICUs) and establish new cross‐sectional reference ranges for the serum GGT levels in a cohort of neonates between 26 and 42 weeks' gestational age in 1 centre.

Methods:

From January 1, 2010 to December 31, 2012, liver function tests including serum GGT measurements were performed in 705 newborns who were admitted to NICUs because of different aetiologies at Gazi University School of Medicine Hospital, Ankara, Turkey. Infants with Apgar score <8 at the fifth minute, any metabolic or liver disease, cholestasis, congenital infection, culture‐proven sepsis, elevated serum aminotransferases, and who were treated with phenobarbital were excluded. Clinical and laboratory data of 583 neonates were analysed retrospectively. GGT was measured by enzymatic method using the Abbott Architect C16000 autoanalyser. Mean, 2.5th, and 97.5th percentiles were used to express the reference range data.

Results:

Four hundred sixty‐one GGT values of 200 preterm infants and 501 GGT values of 383 term infants during the first 28 days after birth were analysed. Serum GGT levels of preterm infants in the first 7 days and between 8 and 28 days after delivery were (mean ± standard deviation; 141.81 ± 88.56 U/L and 131.17 ± 85.53 U/L) similar to term infants (139.90 ± 86.46 U/L and 144.56 ± 86.51 U/L), respectively (P = 0.649 and P = 0.087). Serum GGT levels were found to be significantly higher in male infants (no need of query) (145.98 ± 93.68 U/L) than female infants (132.18 ± 78.97 U/L) (P = 0.035), and infants born vaginally (152.24 ± 90.71 U/L) also had higher serum GGT activity than those born by caesarean section (135.38 ± 85.37 U/L) (P = 0.005).

Conclusions:

A new reference range for serum GGT levels that is higher than previous reference values can identify neonates with truly abnormal results and prevent unnecessary interventions.
Obesity and Symptomatic Cholelithiasis in Childhood
Authors: Fradin Kelly , Racine Andrew D. , Belamarich Peter F.
Published: August 2013

Objectives:

The aims of this study were to correlate the temporal trends in obesity prevalence with hospitalization rates for symptomatic cholelithiasis and to estimate the strength of the association between obesity and symptomatic cholelithiasis in patients hospitalized at an urban children's hospital in New York serving a multiethnic population.

Methods:

Using obesity prevalence data from the National Health and Nutrition Examination Survey and the rates of hospitalization for cholelithiasis derived from the Kids' Inpatient Database for 1997–2007, we estimated a correlation and a linear regression. We conducted a retrospective, case‐control study in which each case ages 4 to 20 years with symptomatic cholelithiasis was individually matched to a control admitted with appendicitis based on age, sex, ethnicity, and race.

Results:

The prevalence of obesity and the cholelithiasis hospitalization rate increased over time (R = 0.87, P = 0.0025). For every 1% increase in the obesity rate among children, the rate of hospitalization for gallstones increased by 0.65/100,000 children (R2 = 0.75, P = 0.0025, 95% confidence interval [CI] 0.32–0.99). The odds ratio for obesity in cases versus controls was 5.78 (n = 518, P < 0.0001, 95% CI 3.50–9.53). We found a significant dose‐response effect, which showed that for every 1 z score increase in body mass index, the risk of cholelithiasis was increased by 79% (P < 0.0001, 95% CI 1.5–2.13).

Conclusions:

The national trend in the prevalence of obesity from 1997 to 2009 was significantly correlated with increasing rates of hospitalization for pediatric cholelithiasis. Our case‐control study suggests that obesity is a significant risk factor for hospital admission because of cholelithiasis.
Molecular eyes: proteins that transform light into biological information
Authors: Kennis John T. M. , Mathes Tilo
Published: August 2013

Most biological photoreceptors are protein/cofactor complexes that induce a physiological reaction upon absorption of a photon. Therefore, these proteins represent signal converters that translate light into biological information. Researchers use this property to stimulate and study various biochemical processes conveniently and non-invasively by the application of light, an approach known as optogenetics. Here, we summarize the recent experimental progress on the family of blue light receptors using FAD (BLUF) receptors. Several BLUF photoreceptors modulate second messenger levels and thus represent highly interesting tools for optogenetic application. In order to activate a coupled effector protein, the flavin-binding pocket of the BLUF domain undergoes a subtle rearrangement of the hydrogen network upon blue light absorption. The hydrogen bond switch is facilitated by the ultrafast light-induced proton-coupled electron transfer (PCET) between a tyrosine and the flavin in less than a nanosecond and remains stable on a long enough timescale for biochemical reactions to take place. The cyclic nature of the photoinduced reaction makes BLUF domains powerful model systems to study protein/cofactor interaction, protein-modulated PCET and novel mechanisms of biological signalling. The ultrafast nature of the photoconversion as well as the subtle structural rearrangement requires sophisticated spectroscopic and molecular biological methods to study and understand this highly intriguing signalling process.
Technical and cost efficiency of rural household apple production
Authors: Wang Lijia , Huo Xuexi , Kabir Shajahan
Published: August 2013

Purpose

At the center of apple production province in China, how to increase apple per unit yield and to improve apple production efficiency in Shaanxi become big issues. The objectives of this paper are to investigate the technical efficiency (TE) and cost efficiency (CE) of apple orchard and to analyse determinants which affect apple production efficiency. The paper aims to discuss these issues.

Design/methodology/approach

This paper conducts a two‐stage DEA to achieve the objectives. In the first‐stage, a cost minimization model is applied to measure apple production efficiency. Then, a Tobit model is provided to estimate regression coefficients which are used to adjust the efficiency scores in the first‐stage.

Findings

The results indicate that TE and CE are rather low in Shaanxi. The research also explores that the inefficient production of apple farmers is caused mainly by two aspects. One is the inefficient apple orchards operation of farmers. The other is the disadvantageous environmental conditions which heavily affect apple growth and fruit bearing situation.

Originality/value

Most of the research are based on national statistical data, and only measure the TE. This paper primarily focuses on the estimation of efficiency scores with the data involved in both quantity and price information of traditional inputs and outputs based on 255 apple farmers in Shaanxi. Specifically, This paper also consider farmer's opportunity cost to which little literature refers. The results not only reveal the efficient determinants of apple production, but also provide suggestions for agricultural policy makers.
Decision making with the uncertain IMOWAD operator
Authors: Zeng Shouzhen
Published: August 2013

Purpose

The purpose of this paper is to present a new decision making technique called the uncertain induced Minkowski OWA distance (UIMOWAD) operator.

Design/methodology/approach

The developed UIMOWAD operator is a new aggregation operator that uses the IOWA operator, the Minkowski distance and interval numbers. It is an extension of the IMOWAD operator that uses uncertain information in the aggregation represented in the form of interval numbers.

Findings

The UIMOWAD operator is very suitable to deal with complex reordering processes that represent a wide range of factors in an uncertain environment that can be assessed with interval numbers.

Research limitations/implications

Clearly, this paper is devoted to the OWA operator and uncertain theory.

Practical implications

The UIMOWAD operator is applicable in a wide range of situations such as decision‐making, statistics, engineering and economics.

Originality/value

This paper fulfils an identified need to study how to make a decision according to expert's interest in uncertain environment.
Tumor necrosis factor‐like weak inducer of apoptosis and its receptor fibroblast growth factor‐inducible 14 are expressed in urticarial vasculitis
Authors: Li Mengmeng , Chen Tao , Guo Zaipei , Li Jingyi , Cao Na
Published: August 2013

Tumor necrosis factor (TNF)‐like weak inducer of apoptosis (TWEAK), a member of the TNF family, has been implicated as a pro‐inflammatory cytokine in many types of autoimmune and infectious diseases. However, information about TWEAK in dermatological diseases is limited. To date, no studies have investigated the roles of TWEAK in patients with urticarial vasculitis (UV). This study aimed to assess serum TWEAK levels, together with TWEAK and fibroblast growth factor‐inducible 14 (Fn14) expressions of skin lesions in patients with UV. Serum TWEAK levels in patients with UV, together with patients with cutaneous leukocytoclastic angiitis (CLA) and healthy controls were detected by enzyme‐linked immunosorbent assay; TWEAK and Fn14 expressions of skin lesions were analyzed by immunohistochemistry. Results showed that TWEAK and Fn14 were abundantly expressed in the dermal vessel wall of lesional skin in patients with UV but not healthy controls. Serum TWEAK levels in the acute stage in patients with UV were significantly higher than those in the convalescent stage and healthy controls. Serum TWEAK levels were elevated significantly in patients with CLA compared with those in healthy controls. Our previous study indicated that TWEAK may be an important mediator for the development of vascular inflammation in skin. In addition, we also found that TWEAK blockade substantially reduced vascular damage and perivascular leukocyte infiltrates in lipopolysaccharide‐induced cutaneous vasculitis. Our study shows that TWEAK may be associated with the pathogenesis of UV; it is therefore suggested that TWEAK may be a potential therapeutic target for UV and other types of cutaneous vasculitis.
Thermal Modifications of Root Transparency and Implications for Aging: A Pilot Study
Authors: Gibelli Daniele , De Angelis Danilo , Rossetti Francesca , Cappella Annalisa , Frustaci Michela , Magli Francesca , Mazzarelli Debora , Mazzucchi Alessandra , Cattaneo Cristina
Published: August 2013

Root transparency has proven to be related to age and has been considered by different odontological methods for age estimation. Very little is known concerning possible variations of root transparency with heat, although the applicability of the method to burnt remains depends on the possible modifications of this specific variable. This pilot study presents the results of an experiment performed on 105 teeth obtained from dental patients and autopsy material, heated in an industrial oven at 50°C, 100°C, 150°C and 200°C. Root transparency was measured before and after the charring experiment. The heating process proved to radically modify root transparency, which decreased in 20% of samples at 50°C, in 34.6% at 100°C, in 50% at 150°C, in 77% at 200°C. The overall correlation index (CI) between decrease in root transparency and increase in temperature amounted to 0.96. These results show that heat may modify root transparency and suggest caution in using methods based on root transparency for age estimation.
Influence of dietary feathers on the fecal microbiota in captive Arctic fox: Do dietary hair or feathers play a role in the evolution of carnivorous mammals?
Authors: ZHANG Liang , YANG Shuhui , XU Yanchun , DAHMER Thomas D.
Published: August 2013

Hair and feathers are composed of keratin and are indigestible, inalimental and unpalatable for carnivores. However, carnivores often ingest hair and feathers during feeding or when grooming. We hypothesized that ingestion of hair and feathers changes species diversity and relative abundance of bacteria in the gut of carnivores. To test this hypothesis, we added disinfected poultry down feathers to the normal diet of captive Arctic foxes (Alopex lagopus). We then used fluorescently labeled terminal restriction fragments (T‐RFs) to examine changes in fecal bacterial diversity and abundance. The results showed that the number of bacterial species increased significantly after feather ingestion, but that total abundance was unchanged. This demonstrated that addition of disinfected feathers to the diet stimulated increased production among less abundant bacteria, resulting in a balancing of relative abundance of different bacterial species, or that some newly‐ingested microbial species would colonize the gut because a suitable microhabitat had become available. This implies that the overall production of bacterial metabolites would be made up of a greater range of substances after feather ingestion. On one hand, the host's immune response would be more diverse, increasing the capacity of the immune system to regulate gut microflora. On the other hand, the animal's physiological performance would also be affected. For wild animals, such altered physiological traits would be subjected to natural selection, and, hence, persistent geographic differences in the character of ingested feathers or fur would drive speciation.
Clinical outcomes and direct costings of endoluminal clipping compared to surgery in the management of iatrogenic colonic perforation
Authors: Chan Wah‐Kheong , Roslani April Camilla , Law Chee‐Wei , Goh Khean‐Lee , Mahadeva Sanjiv
Published: August 2013

Objective

To compare the outcomes and costs of endoluminal clipping and surgery in the management of iatrogenic colonic perforation.

Methods

A retrospective, single‐center, clinical and economic analysis of outcomes and costings between endoluminal clipping and surgery in consecutive cases of iatrogenic colonic perforations was conducted.

Results

In total, 7136 colonoscopies performed over a 6‐year period were complicated by 12 (0.17%) perforations. Seven cases were treated by endoscopic clipping (with a success rate of 71.4%) and five with immediate surgery. Both groups of patients had similar clinical and individual characteristics. Patients who were treated with endoscopic clipping had a shorter period of hospitalization (median 9 vs 13 days) compared to surgery, but this was not statistically significant. Compared to patients who had immediate surgery, the median direct health‐care costs for all procedures (US$ 115.10 vs US$ 1479.50, P = 0.012) and investigations (US$ 124.60 vs US$ 512.90, P = 0.048) during inpatient stay were lower for the endoscopic clipping group. There was a trend towards a lower overall inpatient median cost for patients managed with endoscopic clipping compared to surgery (US$ 1481.70 vs US$ 3281.90, P = 0.073).

Conclusion

Endoluminal clipping may be more cost‐effective than surgery in the management of iatrogenic colonic perforations.
Validation of a single‐nucleotide polymorphism panel for parentage testing of farmed red deer
Authors: Gudex B. , Walker M. , Fisher P. , Spelman R.
Published: August 2013

Red deer behaviour prevents the accurate physical matching of dams to fawns and, therefore, breeders have to rely on DNA‐based parentage testing. A panel consisting of 100 single nucleotide polymorphism markers, with an average minor allele frequency of 0.25, was able to resolve 92% of fawns to both parents. In comparison, an existing 12‐marker microsatellite panel was able to resolve 68% of fawns to both parents. When excluding dam DNA information, the single nucleotide polymorphism panel matched 81% of the fawns to their sires and the microsatellite panel 71%.
Anti‐Müllerian hormone levels in salpingectomized compared with nonsalpingectomized women with tubal factor infertility and women with unexplained infertility
Authors: Grynnerup Anna G.‐A. , Lindhard Anette , Sørensen Steen
Published: August 2013

Objective

To investigate the consequence of salpingectomy on ovarian reserve by measuring anti‐Müllerian hormone (AMH) levels before in vitro fertilization (IVF) treatment in salpingectomized women compared with nonsalpingectomized women with tubal factor infertility, women with unexplained infertility and fertile control women, and to evaluate whether AMH levels could predict IVF outcome.

Design

Cross‐sectional study extended from a previous prospective study.

Setting

Four university fertility clinics.

Patients

Seventy‐one women with infertility and 21 fertile controls.

Interventions

Blood sampling and IVF and embryo transfer in the following cycle.

Main outcome measure

Serum AMH levels and oocytes retrieved.

Results

Anti‐Müllerian hormone levels were significantly lower in the salpingectomy infertility group (median 16.1, range 5.2–54 pmol/L) compared with the nonsalpingectomy tubal factor infertility group (median 23.4, range 3.5–50 pmol/L; p = 0.04). In all groups, AMH levels correlated positively with the number of oocytes retrieved. AMH predicted poor response (five or fewer oocytes) with a sensitivity and specificity of 90% and 70%, at a 19 pmol/L cut‐off value.

Conclusion

Serum AMH levels were lower in salpingectomized women compared with women with tubal factor infertility and preserved Fallopian tubes, indicating that ovarian reserve might be affected by tubal surgery. Furthermore, serum AMH levels could predict a poor oocyte response (five or fewer oocytes) in the study group of infertile women.
Hypermethylation of HOXA10 gene in mid‐luteal endometrium from women with ovarian endometriomas
Authors: Fambrini Massimiliano , Sorbi Flavia , Bussani Cecilia , Cioni Riccardo , Sisti Giovanni , Andersson Karin L.
Published: August 2013

A decrease in HOXA10 gene expression in eutopic mid‐secretory endometrium has been found in women with endometriosis‐associated infertility. Promoter hypermethylation of HOXA10 is thought to be the leading mechanism for epigenetic gene regulation in patients with endometriosis. In our series we documented significantly higher HOXA10 promoter methylation levels in women with ovarian endometriomas than in healthy controls during the mid‐luteal phase. Development of epigenetic‐based strategies for non‐surgical treatment of infertility related to ovarian endometriomas could be an attractive field of research in the coming years.
Remote Monitoring of Left Ventricular Assist Device Parameters After HeartAssist‐5 Implantation
Authors: Pektok Erman , Demirozu Zumrut Tuba , Arat Nurcan , Yildiz Omer , Oklu Emine , Eker Deniz , Ece Ferah , Ciftci Cavlan , Yazicioglu Nuran , Bayindir Osman , Kucukaksu Deniz Suha
Published: August 2013

Although several left ventricular assist devices (LVADs) have been used widely, remote monitoring of LVAD parameters has been available only recently. We present our remote monitoring experience with an axial‐flow LVAD (HeartAssist‐5, MicroMed Cardiovascular, Inc., Houston, TX, USA). Five consecutive patients who were implanted a HeartAssist‐5 LVAD because of end‐stage heart failure due to ischemic (n = 4) or idiopathic (n = 1) cardiomyopathy, and discharged from hospital between December 2011 and January 2013 were analyzed. The data (pump speed, pump flow, power consumption) obtained from clinical visits and remote monitoring were studied. During a median follow‐up of 253 (range: 80–394) days, fine tuning of LVADs was performed at clinical visits. All patients are doing well and are in New York Heart Association Class‐I/II. A total of 39 alarms were received from three patients. One patient was hospitalized for suspected thrombosis and was subjected to physical examinations as well as laboratory and echocardiographic evaluations; however, no evidence of thrombus washout or pump thrombus was found. The patient was treated conservatively. Remaining alarms were due to insufficient water intake and were resolved by increased water consumption at night and summer times, and fine tuning of pump speed. No alarms were received from the remaining two patients. We believe that remote monitoring is a useful technology for early detection and treatment of serious problems occurring out of hospital thereby improving patient care. Future developments may ease troubleshooting, provide more data from the patient and the pump, and eventually increase physician and patient satisfaction. Despite all potential clinical benefits, remote monitoring should be taken as a supplement to rather than a substitute for routine clinical visits for patient follow‐up.