bluuebunny/crossref_metadata_2025 huggingface dataset:
Semi‐analytic selection of sub‐carrier allocation schemes in uplink orthogonal frequency division multiple access
Authors: Choi Kwonhue
Published: August 2013

The authors propose a generalised framework that analytically compares different sub‐carrier allocation (SA) or sub‐channelisation schemes (such as interleaved SA (ISA), localised SA (LSA) or hybrid schemes) in uplink (UL) orthogonal frequency division multiple access (OFDMA). The ultimate goal of the proposed framework is to systematically determine the best SA scheme among the considered candidates for a given condition of inter‐user frequency offsets (IUFOs) and the target bit error rate (BER). As an illustration, two typical SA schemes are considered, that is, ISA and LSA for comparison. First, based on the well‐known fact that multiple access interference by IUFO and frequency diversity gain are both dictated by the employed SA scheme, the authors propose a semi‐analytic approach to derive coded BER curve formula as a function of frequency offset bound (FOB) for each scheme. Then, the signal‐to‐noise ratio gain of ISA over LSA for various target BERs and FOBs is derived. Finally, the cutoff FOB over which ISA obtains worse than LSA is obtained and its functional relationship with the target BER is investigated. By following the overall procedure in the proposed framework, the best SA scheme among the various SA candidates for the general UL OFDMA systems with arbitrary system parameters can be chosen.
Linear closed‐form solution for wireless localisation with ultra‐wideband/chirp spread spectrum signals based on difference of squared range measurements
Authors: Cho Seong Yun , Kim Byung Doo
Published: August 2013

In many practical applications of wireless localisation with ultra‐wideband or chirp spread spectrum signals based on distance measurements, iterative least squares (ILS) method and direct solution (DS) method have been used. In these methods, some deployment conditions of reference nodes may cause problems such as: local minimum problem in the ILS method and red sea zone problem in the DS method. To overcome these problems, a linear closed‐form solution based on difference of squared range measurements is presented in this study. The measurement used in this solution is the difference of squared range measurements instead of distance measurements. Also, it is shown that the proposed solution is equal to the range‐difference measurements‐based closed‐form solution. Some Monte Carlo simulations were conducted to illustrate the proposed solution and demonstrate its performance. Through actual experiments, the validity of the proposed solution is confirmed.
Efficient mechanism to exchange group membership identities among nodes in wireless sensor networks
Authors: Mishra Alekha Kumar , Turuk Ashok Kumar
Published: August 2013

It is necessary for nodes in wireless sensor networks to exchange their group membership identities in certain applications such as cluster formation and clone detection. The communication cost associated with exchanging group membership identities is higher especially in a dense network. Existing schemes make use of Bloom filter in exchanging membership information. Although the Bloom filter is an efficient mechanism for exchanging membership information, yet it suffers from higher probability of false positive, that is, a node may be detected to be a member of a group, when it is not. In this study, the authors propose two schemes called transpose bit‐pair coding (TBC), and sub‐mat coding (SMC) for exchanging group membership information. The proposed schemes do not generate false positive, and have lower communication and storage overhead. The authors have compared TBC and SMC with Bloom filter. Parameters considered for the comparison are: (i) communication overhead in terms of number of bits required to exchange the group membership information and (ii) probability of false positive. It is observed that the communication overhead in TBC and SMC is significantly lower in comparison with Bloom filter and the schemes have no cases of false positive.
Nucleosides analogues recognition by molecularly imprinted polymer‐coated Love wave sensor
Authors: Lebal N. , Hallil H. , Dejous C. , Plano B. , Krstulja A. , Delepée R. , Agrofoglio L. , Rebière D.
Published: August 2013

Presented is a process for thin film molecularly imprinted polymer (MIP) coating based on commercial nucleotides adenosine monophosphate (AMP). The compatibility of the MIP film with acoustic propagation and sensor sensitivity for rebinding of AMP have been verified. Thin and porous layers of AMP‐based MIP layers were successfully deposited on the sensor surface. Detection tests of AMP have been performed in aqueous media. The sensor response was recorded in terms of frequency and total insertion losses after both steps: AMP extraction from MIP then AMP rebinding. The sensor showed high sensitivity to 25 ppm AMP concentration. The effect of the extraction time on rebinding capacity of the MIP layer has been proven.
Femtogram aerosol nanoparticle mass sensing utilising vertical silicon nanowire resonators
Authors: Wasisto Hutomo Suryo , Merzsch Stephan , Stranz Andrej , Waag Andreas , Uhde Erik , Salthammer Tunga , Peiner Erwin
Published: August 2013

Vertically aligned silicon nanowire (SiNW)‐based resonators were fabricated and utilised to detect aerosol nanoparticles (NPs) by measuring their resonant frequency shifts caused by the additional mass of trapped NPs. Inductively coupled plasma cryogenic dry etching and multiple thermal oxidations are used in the fabrication of silicon nanowire (SiNW) arrays. The SiNWs were coated with gold for contacting to the homebuilt electrostatic NP sampler to collect the flowing NPs. In order to have a dynamic resonance operation in the frequency measurement system, a piezoelectric shear actuator was mounted onto the SiNWs. Examined in a TiO2 aerosol sampling with a total concentration of ∼8500 NP/cm3, the fabricated sensor exhibited its feasibility as a nanobalance to measure aerosol NP mass at the femtogram level with a mass sensitivity of 7.1 Hz/fg and a mass resolution of 31.6 fg. The NP sampling efficiency of the developed miniaturised NP sampler was found to be three times higher than that of the commercial nanometer aerosol sampler (NAS, TSI 3089). An ultrasonic removal method was used to detach the adhered NPs and further extend the operating life of the sensor.
Single-Level Degenerative Cervical Disc Disease and Driving Disability: Results from a Prospective, Randomized Trial
Authors: Kelly Michael P. , Mitchell M. David , Hacker Robert J. , Riew K. Daniel , Sasso Rick C.
Published: August 2013

Study Design

Post hoc analysis of prospective, randomized trial.

Objective

To investigate the disability associated with driving and single-level degenerative, cervical disc disease and to investigate the effect of surgery on driving disability.

Methods

Post hoc analysis of data obtained from three sites participating in a multicenter, randomized, controlled trial comparing cervical disc arthroplasty (TDA) with anterior cervical discectomy and fusion (ACDF). The driving subscale of the Neck Disability Index (NDI) was analyzed for all patients. A dichotomous severity score was created from the NDI. Statistical comparisons were made within and between groups.

Results

Two-year follow-up was available for 118/135 (87%) patients. One half of the study population (49.6%) reported moderate or severe preoperative driving difficulty. This disability associated with driving was similar among the two groups (ACDF: 2.5 ± 1.1, TDA: 2.6 ± 1.0, p = 0.646). The majority of patients showed improvement, with no or little driving disability, at the sixth postoperative week (ACDF: 75%, TDA: 90%, p = 0.073). At no follow-up point did a difference exist between groups according to the severity index.

Conclusions

Many patients suffering from radiculopathy or myelopathy from cervical disc disease are limited in their ability to operate an automobile. Following anterior cervical spine surgery, most patients are able to return to comfortable driving at 6 weeks.
Cathodoluminescence and electron beam induced current investigations of stacking faults mechanically introduced in 4H-SiC in the brittle domain
Authors: Yakimov E. B. , Regula G. , Pichaud B.
Published: August 2013

The electrical and optical properties of stacking faults (SFs), introduced in 4H-SiC by plastic deformation in the brittle domain of temperature (823 K and 973 K), were studied by cathodoluminescence and electron beam induced current (EBIC) methods. As expected from previous studies, at 973 K, all the SFs generated were found to be double stacking faults (DSFs) and at 823 K, the latter also constituted the major part of the defects. Rather surprisingly, in addition to DSFs, single stacking faults (SSFs) were revealed but only very near the defect nucleation area. Moreover, an inversion of DSF EBIC contrast was obtained which designates these defects as relevant candidates for electron guides to enhance detector performances. Eventually, no dark contrast corresponding to the casual recombination activity of the partial dislocations dragging the DSFs was observed.
Stabilizer information inequalities from phase space distributions
Authors: Gross David , Walter Michael
Published: August 2013

The Shannon entropy of a collection of random variables is subject to a number of constraints, the best-known examples being monotonicity and strong subadditivity. It remains an open question to decide which of these “laws of information theory” are also respected by the von Neumann entropy of many-body quantum states. In this article, we consider a toy version of this difficult problem by analyzing the von Neumann entropy of stabilizer states. We find that the von Neumann entropy of stabilizer states satisfies all balanced information inequalities that hold in the classical case. Our argument is built on the fact that stabilizer states have a classical model, provided by the discrete Wigner function: The phase-space entropy of the Wigner function corresponds directly to the von Neumann entropy of the state, which allows us to reduce to the classical case. Our result has a natural counterpart for multi-mode Gaussian states, which sheds some light on the general properties of the construction. We also discuss the relation of our results to recent work by Linden, Ruskai, and Winter [“The quantum entropy cone of stabiliser states,” e-print arXiv:1302.5453].
Lennard-Jones systems near solid walls: Computing interfacial free energies from molecular simulation methods
Authors: Benjamin Ronald , Horbach Jürgen
Published: August 2013

Different computational techniques in combination with molecular dynamics computer simulation are used to determine the wall-liquid and the wall-crystal interfacial free energies of a modified Lennard-Jones (LJ) system in contact with a solid wall. Two different kinds of solid walls are considered: a flat structureless wall and a structured wall consisting of an ideal crystal with the particles rigidly attached to fcc lattice sites. Interfacial free energies are determined by a thermodynamic integration scheme, the anisotropy of the pressure tensor, the non-equilibrium work method based on Bennett acceptance criteria, and a method using Cahn's adsorption equations based on the interfacial thermodynamics of Gibbs. For the flat wall, interfacial free energies as a function of different densities of the LJ liquid and as a function of temperature along the coexistence curve are calculated. In the case of a structured wall, the interaction strength between the wall and the LJ system and the lattice constant of the structured wall are varied. Using the values of the wall-liquid and wall-crystal interfacial energies along with the value for the crystal-liquid interfacial free energy determined previously for the same system by the “cleaving potential method,” we obtain the contact angle as a function of various parameters; in particular, the conditions are found under which partial wetting occurs.
An experimental investigation of vortex-induced vibration with nonlinear restoring forces
Authors: Mackowski A. W. , Williamson C. H. K.
Published: August 2013

We experimentally examine the amplitude of a bluff body undergoing vortex-induced vibration (VIV) supported by linear and various nonlinear structural forces. This investigation is made possible by our Cyber-Physical Fluid Dynamics force-feedback technique; using it, we can impose arbitrary nonlinear restoring forces on a circular cylinder in our water channel. For the range of nonlinearities examined, detailed analysis allows one to understand and predict the response of the nonlinear structural system using knowledge of a standard, linear VIV system. We also present a case study examining the potential of nonlinear springs to aid in a VIV-based energy harvesting device. Appropriate choices of the spring's nonlinearity allow the hypothetical energy harvester to operate at high performance over a much larger range of Reynolds number than a standard system.
Aspect-ratio dependency of Rayleigh-Bénard convection in box-shaped containers
Authors: Wagner Sebastian , Shishkina Olga
Published: August 2013

We report on a numerical study of the aspect-ratio dependency of Rayleigh-Bénard convection, using direct numerical simulations. The investigated domains have equal height and width while the aspect ratio Γ of depth per height is varied between 1/10 and 1. The Rayleigh numbers \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra for this study variate between 105 and 109, while the Prandtl number is \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Pr}} = 0.786$\end{document}Pr=0.786. The main focus of the study concerns the dependency of the Nusselt number \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Nu}}$\end{document}Nu and the Reynolds number \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Re}}$\end{document}Re on \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra and Γ. It turns out that due to Γ, differences to the cubic case (i.e., Γ = 1) in \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Nu}}$\end{document}Nu of up to 55% and in \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Re}}$\end{document}Re of up to 97% occur, which decrease for increasing \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra. In particular for small Γ sudden drops in the \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra-scaling of \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Nu}}$\end{document}Nu and \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Re}}$\end{document}Re appear for \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}\approx 10^6$\end{document}Ra≈106. Further analysis reveals that these correspond to the onset of unsteady motion accompanied by changes in the global flow structure. The latter is investigated by statistical analysis of the heat flux distribution on the bottom and top plates and a decomposition of the instantaneous flow fields into two-dimensional modes. For \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra slightly above the onset of unsteady motion (i.e., \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}\approx 10^6$\end{document}Ra≈106) for all considered Γ ⩽ 1/3 a four-roll structure is present, which corresponds to thermal plumes moving vertically through the domain's center. For \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}\ge 10^7$\end{document}Ra≥107, also for small Γ, a single-roll structure is dominant, in agreement with two-dimensional simulations and experiments at larger \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Ra}}$\end{document}Ra and \documentclass[12pt]{minimal}\begin{document}$\mbox{\textit {Pr}}$\end{document}Pr.
Infrared optical properties of amorphous and nanocrystalline Ta2O5 thin films
Authors: Bright T. J. , Watjen J. I. , Zhang Z. M. , Muratore C. , Voevodin A. A. , Koukis D. I. , Tanner D. B. , Arenas D. J.
Published: August 2013

The optical constants of tantalum pentoxide (Ta2O5) are determined in a broad spectral region from the visible to the far infrared. Ta2O5 films of various thicknesses from approximately 170 to 1600 nm are deposited using reactive magnetron sputtering on Si substrates. X-ray diffraction shows that the as-deposited films are amorphous, and annealing in air at 800 °C results in the formation of nanocrystalline Ta2O5. Ellipsometry is used to obtain the dispersion in the visible and near-infrared. Two Fourier-transform infrared spectrometers are used to measure the transmittance and reflectance at wavelengths from 1 to 1000 μm. The surface topography and microstructure of the samples are examined using atomic force microscopy, confocal microscopy, and scanning electron microscopy. Classical Lorentz oscillators are employed to model the absorption bands due to phonons and impurities. A simple model is introduced to account for light scattering in the annealed films, which contain micro-cracks. For the unannealed samples, an effective-medium approximation is used to take into account the adsorbed moisture in the film and a Drude free-electron term is also added to model the broad background absorption.
Atomic resolution chemical bond analysis of oxygen in La2CuO4
Authors: Haruta M. , Nagai T. , Lugg N. R. , Neish M. J. , Nagao M. , Kurashima K. , Allen L. J. , Mizoguchi T. , Kimoto K.
Published: August 2013

The distorted CuO6 octahedron in La2CuO4 was studied using aberration-corrected scanning transmission electron microscopy at atomic resolution. The near-edge structure in the oxygen K-edge electron energy-loss spectrum was recorded as a function of the position of the electron probe. After background subtraction, the measured spectrum image was processed using a recently developed inversion process to remove the mixing of signals on the atomic columns due to elastic and thermal scattering. The spectra were then compared with first-principles band structure calculations based on the local-density approximation plus on-site Coulomb repulsion (LDA + U) approach. In this article, we describe in detail not only anisotropic chemical bonding of the oxygen 2p state with the Cu 3d state but also with the Cu 4p and La 5d/4f states. Furthermore, it was found that buckling of the CuO2 plane was also detectable at the atomic resolution oxygen K-edge. Lastly, it was found that the effects of core-hole in the O K-edge were strongly dependent on the nature of the local chemical bonding, in particular, whether it is ionic or covalent.
Nano-superconducting quantum interference devices with continuous read out at milliKelvin temperatures
Authors: Hazra D. , Kirtley J. R. , Hasselbach K.
Published: August 2013

We describe aluminum-niobium-tungsten trilayer Nano-Superconducting Quantum Interference Devices (NanoSQUIDs) that can be read out continuously down, in temperature, to at least 230 mK. They show voltage oscillations up to at least 20 mT in field. A voltage modulation of 500 μV, voltage sensitivity of 2 mV/Φ0, and white noise floor better than 5×10−5 Φ0/Hz have been obtained. Flux noise places them between conventional low impedance SQUIDs and standard nanoSQUIDs. High sensitivity and ease of implementation make this new kind of nanoSQUID attractive for magnetic detection schemes on the nanoscale and low temperature scanning SQUID microscopy.
Nanoparticle aggregation logic computing controlled by DNA branch migration
Authors: Zhang Cheng , Ma Jingjing , Yang Jing , Inaki Schlaberg H. , Liu Shi , Xu Jin
Published: August 2013

In this work, nanoparticle aggregation is utilized to establish a nanoparticle computing system, and the computing process is triggered by adding specific DNA signals. Through DNA strand displacement, cascading regulations of aggregations are implemented. The logic computing operations of “OR” and “OR-AND” are realized by a color change, resulting from the aggregations induced by DNA self-assembly. All reactions are performed under room temperature and without changing ion strength in buffers. By analysis of the color, the computing results can be detected through naked eyes. In addition, the aggregation structures are distinctly demonstrated by transmission electron microscopy.
A battery-less photo-detector enabled with simultaneous ferroelectric sensing and energy harnessing mechanism
Authors: Lai Szu Cheng , Yao Kui , Chen Yi Fan
Published: August 2013

A self-sustainable mechanism for simultaneously sensing and harnessing photon energy was proposed and implemented to create a battery-less and wire-less ultraviolet sensor made of ferroelectric lead lanthanum zirconate titanate thin film with in-plane polarization configuration. The mechanism involved accumulating and storing the photovoltaic charge, and transferring the stored charge via a piezoelectric switch to a radio frequency transmitter. The time-interval between the radio frequency pulses generated by the transmitter was inversely proportional to the photo-intensity. The sustainability of the operation was ascribed to the low leakage, high photovoltage, and linear current-voltage characteristics of ferroelectric sensing material instead of semiconductors.
A high-efficiency double quantum dot heat engine
Authors: Liu Y. S. , Yang X. F. , Hong X. K. , Si M. S. , Chi F. , Guo Y.
Published: August 2013

High-efficiency heat engine requires a large output power at the cost of less input heat energy as possible. Here we propose a heat engine composed of serially connected two quantum dots sandwiched between two metallic electrodes. The efficiency of the heat engine can approach the maximum allowable Carnot efficiency ηC. We also find that the strong intradot Coulomb interaction can induce additional work regions for the heat engine, whereas the interdot Coulomb interaction always suppresses the efficiency. Our results presented here indicate a way to fabricate high-efficiency quantum-dot thermoelectric devices.
Colour Detection Thresholds in Faces and Colour Patches
Authors: Tan Kok Wei , Stephen Ian D
Published: August 2013

Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior32 216–227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology30 845–857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (Δ E = 1.2) to quite large differences (Δ E = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters2 217–221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status.
Making the best of the worst of times: traits underlying combined shade and drought tolerance of Ruscus aculeatus and Ruscus microglossum (Asparagaceae)
Authors: Pivovaroff Alexandria , Sharifi Rasoul , Scoffoni Christine , Sack Lawren , Rundel Phil
Published: August 2013

The genus Ruscus (Asparagaceae) consists of evergreen, woody monocot shrubs with modified photosynthetic stems (phylloclades) that occur in dry, shaded woodland areas of the Mediterranean Basin and southern Europe. The combined drought and shade tolerance of Ruscus species challenges the ‘trade-off model’, which suggests that plants can be either drought or shade adapted, but not both. To clarify the potential mechanisms that enable Ruscus species to survive in shaded environments prone to pronounced soil drought, we studied form–function relations based on a detailed trait survey for Ruscus aculeatus L. and Ruscus microglossum Bertol., focusing on gas exchange, hydraulics, morphology, anatomy, and nutrient and isotope composition. We then compared these trait values with published data for other species. R. aculeatus and R. microglossum exhibited numerous traits conferring drought and shade tolerance via reduced demand for resources in general and an ability to survive on stored water. Specific traits include thick phylloclades with low rates of maximum photosynthetic CO2 assimilation, low stomatal conductance to water vapour (gs), low respiration rate, low light compensation point, low shoot hydraulic conductance, low cuticular conductance, and substantial water storage tissue. Ruscus carbon isotope composition values of –33 ‰ were typical of an understory plant, but given the low gs could be associated with internal CO2 recycling. Ruscus appears to be a model for extreme dual adaptation, both physiologically and morphologically, enabling its occupation of shaded sites within drought prone regions across a wide geographical range, including extremely low resource understory sites.
Exploiting a fast neutron mutant genetic resource in Pisum sativum (pea) for functional genomics
Authors: Domoney Claire , Knox Maggie , Moreau Carol , Ambrose Mike , Palmer Sarah , Smith Peter , Christodoulou Vangelis , Isaac Peter G. , Hegarty Matthew , Blackmore Tina , Swain Martin , Ellis Noel
Published: August 2013

A fast neutron (FN)-mutagenised population was generated in Pisum sativum L. (pea) to enable the identification and isolation of genes underlying traits and processes. Studies of several phenotypic traits have clearly demonstrated the utility of the resource by associating gene deletions with phenotype followed by functional tests exploiting additional mutant sources, from both induced and natural variant germplasm. For forward genetic screens, next generation sequencing methodologies provide an opportunity for identifying genes associated with deletions rapidly and systematically. The application of rapid reverse genetic screens of the fast neutron mutant pea population supports conclusions on the frequency of deletions based on phenotype alone. These studies also suggest that large deletions affecting one or more loci can be non-deleterious to the pea genome, yielding mutants that could not be obtained by other means. Deletion mutants affecting genes associated with seed metabolism and storage are providing unique opportunities to identify the products of complex and related gene families, and to study the downstream consequences of such deletions.
Extreme Elemental Processing in a High Schizotypy Population: Relation to Cognitive Deficits
Authors: Haddon Josephine E. , George David N. , Grayson Lois , McGowan Christopher , Honey Robert C. , Killcross Simon
Published: August 2013

The cognitive deficits observed in schizophrenia have been characterized as a failure to utilize task-setting information to guide behaviour, especially in situations in which there is response conflict. Recently, we have provided support for this account; high schizotypy individuals demonstrated inferior biconditional discrimination performance compared to low scorers, but were not impaired on a simple discrimination that did not require the use of task-setting cues. These results may, however, also be explained by the way in which individuals with high schizotypy process stimulus compounds . Here, we examine the initial approaches to solving biconditional and control discrimination tasks of participants with high and low schizotypy scores. In particular, we focus on performance during the first block of training trials to capture processing style before the acquisition of the discrimination tasks. Participants scoring highly on the introvertive anhedonia subscale (which has been allied to the negative and cognitive symptoms of schizophrenia) demonstrated better biconditional performance during the first block of training trials than did low-schizotypy individuals, consistent with a highly elemental approach to stimulus processing. Subsequent recognition tests confirmed this analysis demonstrating that the pattern of performance observed in participants with high schizotypy was associated with a failure to discriminate conjunctions of items that had been seen before from those that had not. These results suggest that the negative/cognitive symptoms of schizophrenia may reflect an extreme bias towards elemental, as opposed to configural, processing of stimulus conjunctions.
A combined omics study on activated macrophages—enhanced role of STATs in apoptosis, immunity and lipid metabolism
Authors: Dinasarapu Ashok Reddy , Gupta Shakti , Ram Maurya Mano , Fahy Eoin , Min Jun , Sud Manish , Gersten Merril J. , Glass Christopher K. , Subramaniam Shankar
Published: August 2013

Background: Macrophage activation by lipopolysaccharide and adenosine triphosphate (ATP) has been studied extensively because this model system mimics the physiological context of bacterial infection and subsequent inflammatory responses. Previous studies on macrophages elucidated the biological roles of caspase-1 in post-translational activation of interleukin-1β and interleukin-18 in inflammation and apoptosis. However, the results from these studies focused only on a small number of factors. To better understand the host response, we have performed a high-throughput study of Kdo2-lipid A (KLA)-primed macrophages stimulated with ATP.

Results: The study suggests that treating mouse bone marrow-derived macrophages with KLA and ATP produces ‘synergistic’ effects that are not seen with treatment of KLA or ATP alone. The synergistic regulation of genes related to immunity, apoptosis and lipid metabolism is observed in a time-dependent manner. The synergistic effects are produced by nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and activator protein (AP)-1 through regulation of their target cytokines. The synergistically regulated cytokines then activate signal transducer and activator of transcription (STAT) factors that result in enhanced immunity, apoptosis and lipid metabolism; STAT1 enhances immunity by promoting anti-microbial factors; and STAT3 contributes to downregulation of cell cycle and upregulation of apoptosis. STAT1 and STAT3 also regulate glycerolipid and eicosanoid metabolism, respectively. Further, western blot analysis for STAT1 and STAT3 showed that the changes in transcriptomic levels were consistent with their proteomic levels. In summary, this study shows the synergistic interaction between the toll-like receptor and purinergic receptor signaling during macrophage activation on bacterial infection.

Availability: Time-course data of transcriptomics and lipidomics can be queried or downloaded from http://www.lipidmaps.org.

Contact:  shankar@ucsd.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Thoracoscopic Approach of the Internal Thoracic Lymphatic Chain
Authors: AbraTo Fernando Conrado , Tamagno Mauro Federico Luis , Abreu Igor Renato Louro Bruno , Alfinito Fernanda Sobreiro , Piato Jose Roberto , Silva Ligia Maria Teixeira Pereira , Terra Ricardo Mingarini , Fernandez Angelo , Jatene Fabio Biscegli
Published: August 2013

Objective

Few studies to date have evaluated the videothoracoscopic approach of the internal thoracic lymphatic chain. However, the histological evaluation of lymph nodes is essential for patients with breast cancer who show lymph node uptake at scintigraphy in the preoperative period and also for patients with lymphoma who have exclusive uptake in these lymph nodes at positron emission tomography for recurrence assessment. Our goal was to evaluate the safety and the change in oncologic approach through this minimally invasive technique.

Methods

This is a review of the prospectively collected data in a group of patients undergoing thoracoscopic biopsy of the thoracic lymphatic chain in patients with breast cancer and lymphoma carried out in our institution between September 2010 and June 2012. The analyzed variables include age, histological type, operated hemithorax, number of resected lymph nodes, neoplastic involvement of the resected lymph nodes, duration of chest tube drainage, length of hospital stay, and perioperative mortality. Complications such as subcutaneous emphysema and necessity for blood transfusion were also evaluated.

Results

Thoracoscopic biopsy was successfully performed in 16 patients, of whom 14 had breast cancer and 2 had lymphoma. The surgical biopsy results changed the treatment in the two patients with lymphoma and avoided radiotherapy in the eight patients with breast cancer who did not have metastases.

Conclusions

The use of the thoracoscopic assessment of the internal thoracic lymphatic chain seems safe and resulted in therapy modification in more than half of our patients, suggesting that it is an effective technique for staging in selected breast cancer and lymphoma cases.
Are There Gender Differences in Outcomes after the Cox-Maze Procedure for Atrial Fibrillation?
Authors: Henry Linda , Hunt Sharon , Holmes Sari D. , Martin Lisa M. , Ad Niv
Published: August 2013

Objective

Atrial fibrillation (AF) management suggests that women do not tolerate medication rhythm control strategies as well as men do; however, AF percutaneous catheter ablation has been found to be favorable. The study purpose was to compare the sex-based outcomes for patients who undergo the Cox-Maze procedure for AF.

Methods

Data were collected through our AF surgical ablation registry. Rhythm was verified by electrocardiogram and 24-hour holter at 6 and 12 months. General health-related quality of life (Short-Form 12) and specific AF symptom burden (Atrial Fibrillation Symptom Checklist: Frequency and Severity, version 3) were obtained at baseline and 12 months.

Results

Since 2005, a total of 540 patients have undergone a Cox-Maze procedure (34% were women). The women presented with higher operative risk [additive European System for Cardiac Operative Risk Evaluation (EuroSCORE), 6.71 ± 2.61 vs 5.25 ± 2.80, t = 5.85, P < 0.001], higher rates of congestive heart failure (49% vs 32%, P < 0.001), and more concomitant mitral valve procedures (32% vs 19%, P = 0.001). Perioperative outcomes were similar. Return to sinus rhythm off antiarrhythmics were not different at 6 and 12 months (78% vs 75%, P = 0.53, and 81% vs 80%, P = 1.00, respectively). Cumulative 2-year survival (93.9% for the men and 89.3% for the women) was not different for all-cause mortality (hazard ratio, 1.47; confidence interval, 0.68–3.21; P = 0.33) and cardiac-related mortality [women: 10/14 (71%) vs men 7/11 (64%), P = 1.00]. Health-related quality of life showed significant improvement; AF symptoms significantly decreased across the sexes.

Conclusions

Outcomes after the Cox-Maze procedure are similar across sex. Atrial fibrillation surgical ablation should be considered a treatment option for women—it is safe and effective, improves general health-related quality of life, and reduces AF symptom burden.
Robotic Multisegment Triangular Resections as an Alternative to Sliding Leaflet Plasty
Authors: Cheema Faisal H. , Cheung Stephen , Jiang Jeffrey , Younus Muhammad Jabran , Roberts Harold G.
Published: August 2013

The sliding leaflet plasty of the posterior mitral leaflet is a complex procedure, both lengthy and technically challenging. A simple alternative is desirable, particularly for a minimally invasive approach. We report a distinct substitute to the conventional sliding leaflet plasty that included triangular resections of P2 and P3 using a robot. These multiple triangular resections enabled a successful mitral valve repair with satisfactory clinical and echocardiographic results. Recognizing the complexity of sliding leaflet plasties, we note that multisegment triangular resections seem to be an easy, expeditious, and effective alternative for the posterior leaflet that is readily performed via a robotic endoscopic approach.
Use of the eSVS Mesh: External Vein Support Does Not Negatively Impact Early Graft Patency
Authors: Genoni Michele , Odavic Dragan , Loblein Helen , Dzemali Omer
Published: August 2013

Objective

The aim of this study was to assess early graft patency in eSVS Mesh–covered saphenous vein grafts (SVGs) in patients undergoing coronary artery bypass grafting.

Methods

In 20 patients meeting criteria for double arterial grafting to the left-sided coronary system and eSVS Mesh–covered SVG to the right-sided coronary system, patency was evaluated intraoperatively by transit time flow measurement and at 5 days postoperatively by computed tomographic angiography.

Results

Twenty patients underwent 49 arterial and 22 venous grafts (mean, 3.55/patient) using off-pump techniques. All grafts were determined to be patent intraoperatively. On computed tomographic angiography, arterial graft patency was 100%. In one venous anastomosis, the distal limb of a sequential graft was occluded, for an overall patency rate of 95%.

Conclusions

The eSVS Mesh does not compromise early SVG patency.
Pectus Excavatum: A Comparison of the Ravitch Repair with the Nuss Thoracoscopic Technique with a Standard Metal Bar or an Absorbable Bar
Authors: Magdi Muhammad Ibrahim Ahmad
Published: August 2013

Objective

Although pectus excavatum repair has evolved to a minimally invasive technique in prepubescent patients, the best approach in adults is less clearly understood. The aim of this study was to identify the preoperative characteristics, operative variables, and postoperative outcomes in adult patients with pectus excavatum undergoing thoracoscopic repair using different bar stabilizers compared with the open surgical repair.

Methods

We conducted a prospective study between July 2009 and July 2012 in a single institution. Thirty-one patients (26 men and 5 women) aged 18 to 35 years were randomly assigned into three groups: group A, 9 patients underwent modified Ravitch repair; group B, 11 patients underwent video-assisted thoracoscopic repair using metal stabilizers; and group C, 11 patients underwent video-assisted thoracoscopic repair using absorbable stabilizers. Preoperative, intraoperative, and postoperative variables are compared between all groups.

Results

In all groups, the preoperative variables were well matched for age, sex, and Haller index. Operative time was 2 hours longer in group A (P = 0.0001). There was no intraoperative complication. Length of hospital stay was 4 days shorter in group A. Morbidity was 23% and composed of pneumothorax (three), wound seroma (two), pleural effusion (one), and stabilizer break (one), occurring more frequently in groups B and C. There was no perioperative mortality. All patients were satisfied with the cosmetic results.

Conclusions

Repair of pectus excavatum in adult patients can be performed effectively through either open surgical technique or thoracoscopy, with no intraoperative complications and with excellent immediate results. Although the operative time for the Ravitch repair was longer, the hospital stay was significantly shorter than that for the video-assisted method.
Plastic proteans: reduced predictability in the face of predation risk in hermit crabs
Authors: Briffa Mark
Published: August 2013

Variation in behaviour occurs at multiple levels, including between individuals (personality) and between situations (plasticity). Behaviour also varies within individuals, and intra-individual variation (IIV) in behaviour describes within-individual residual variance in behaviour that remains after the effects of obvious external and internal influences on behaviour have been accounted for. IIV thus describes how predictable an individual's behaviour is. Differences in predictability, between individuals and between situations, might be biologically significant. For example, behaving unpredictably under predation threat might reduce the chance of capture. Here, we investigated the duration of startle responses in hermit crabs, in the presence and absence of a predator cue. Individuals differed in startle response duration (personality) and while individuals also varied in their sensitivity to risk, mean response time was greater in the presence of a predator (plasticity). Moreover, IIV was greater in the presence of a predator, providing some of the first evidence that the facultative injection of unpredictability into behaviour might represent a strategy for dealing with risk.
Modelling the efficacy of hyperthermia treatment
Authors: Rybiński Mikołaj , Szymańska Zuzanna , Lasota Sławomir , Gambin Anna
Published: August 2013

Multimodal oncological strategies which combine chemotherapy or radiotherapy with hyperthermia, have a potential of improving the efficacy of the non-surgical methods of cancer treatment. Hyperthermia engages the heat-shock response (HSR) mechanism, the main component of which are heat-shock proteins. Cancer cells have already partially activated HSR, thereby hyperthermia may be more toxic to them relative to normal cells. On the other hand, HSR triggers thermotolerance, i.e. hyperthermia-treated cells show an impairment in their susceptibility to a subsequent heat-induced stress. This poses questions about efficacy and optimal strategy for anti-cancer therapy combined with hyperthermia treatment. To address these questions, we adapt our previous HSR model and propose its stochastic extension. We formalize the notion of a HSP-induced thermotolerance. Next, we estimate the intensity and the duration of the thermotolerance. Finally, we quantify the effect of a multimodal therapy based on hyperthermia and a cytotoxic effect of bortezomib, a clinically approved proteasome inhibitor. Consequently, we propose an optimal strategy for combining hyperthermia and proteasome inhibition modalities. In summary, by a mathematical analysis of HSR, we are able to support the common belief that the combination of cancer treatment strategies increases therapy efficacy.
Passive elastic mechanism to mimic fish-muscle action in anguilliform swimming
Authors: Ramananarivo Sophie , Godoy-Diana Ramiro , Thiria Benjamin
Published: August 2013

Swimmers in nature use body undulations to generate propulsive and manoeuvring forces. The anguilliform kinematics is driven by muscular actions all along the body, involving a complex temporal and spatial coordination of all the local actuations. Such swimming kinematics can be reproduced artificially, in a simpler way, by using the elasticity of the body passively. Here, we present experiments on self-propelled elastic swimmers at a free surface in the inertial regime. By addressing the fluid–structure interaction problem of anguilliform swimming, we show that our artificial swimmers are well described by coupling a beam theory with the potential flow model of Lighthill. In particular, we show that the propagative nature of the elastic wave producing the propulsive force is strongly dependent on the dissipation of energy along the body of the swimmer.
Geometric computation theory for morphological filtering on freeform surfaces
Authors: Lou Shan , Jiang Xiangqian , Scott Paul J.
Published: August 2013

Surfaces govern functional behaviours of geometrical products, especially high-precision and high-added-value products. Compared with the mean line-based filters, morphological filters, evolved from the traditional E-system, are relevant to functional performance of surfaces. The conventional implementation of morphological filters based on image-processing does not work for state-of-the-art surfaces, for example, freeform surfaces. A set of novel geometric computation theory is developed by applying the alpha shape to the computation. Divide and conquer optimization is employed to speed up the computational performance of the alpha-shape method and reduce memory usage. To release the dependence of the alpha-shape method on the Delaunay triangulation, a set of definitions and propositions for the search of contact points is presented and mathematically proved based on alpha shape theory, which are applicable to both circular and horizontal flat structuring elements. The developed methods are verified through experimentation.
The radiation of cynodonts and the ground plan of mammalian morphological diversity
Authors: Ruta Marcello , Botha-Brink Jennifer , Mitchell Stephen A. , Benton Michael J.
Published: August 2013

Cynodont therapsids diversified extensively after the Permo-Triassic mass extinction event, and gave rise to mammals in the Jurassic. We use an enlarged and revised dataset of discrete skeletal characters to build a new phylogeny for all main cynodont clades from the Late Permian to the Early Jurassic, and we analyse models of morphological diversification in the group. Basal taxa and epicynodonts are paraphyletic relative to eucynodonts, and the latter are divided into cynognathians and probainognathians, with tritylodonts and mammals forming sister groups. Disparity analyses reveal a heterogeneous distribution of cynodonts in a morphospace derived from cladistic characters. Pairwise morphological distances are weakly correlated with phylogenetic distances. Comparisons of disparity by groups and through time are non-significant, especially after the data are rarefied. A disparity peak occurs in the Early/Middle Triassic, after which period the mean disparity fluctuates little. Cynognathians were characterized by high evolutionary rates and high diversity early in their history, whereas probainognathian rates were low. Community structure may have been instrumental in imposing different rates on the two clades.
Corporate social responsibility in housing management: is it profitable?
Authors: Blomé Gunnar
Published: August 2013

Purpose

The purpose of this paper is to evaluate corporate social responsibility (CSR) in the context of real estate management. Different operation cost indicators are identified and related to the estates’ social condition.

Design/methodology/approach

The empirical material was collected from the company's accounts and by interviews with the staff and is based on a comparison between two similar areas that mainly differed in how much resources the company invested in social projects and maintenance.

Findings

The results indicate that CSR leads to approximately 4.5 percent lower annual operating and maintenance costs, which improved the company's profitability, especially if higher maintenance standards made higher rents possible. Other advantages were improved goodwill, which led to new business opportunities.

Research limitation/implications

The primary issue of the study is to identify consequences of CSR. However, more research is needed about landlord incentives and economic effects of initiated landlord investments. The evaluation method also needs to be further developed and refined.

Originality/value

From a practical perspective, the paper gives a deeper insight into the possible economic advantages of CSR. From the perspective of the scientific community, the paper shows the possibilities in using a comparative evaluation model together with detailed company data in order to identify important indicators and effects.