bluuebunny/crossref_metadata_2025 huggingface dataset:
Deterministic and stochastic channel models implemented in a physical layer simulator for Car-to-X communications
Authors: Nuckelt J. , Schack M. , Kürner T.
Published: August 2011

Abstract. This paper presents a physical (PHY) layer simulator of the IEEE 802.11p standard for Wireless Access in Vehicular Environments (WAVE). This simulator allows the emulation of data transmission via different radio channels as well as the analysis of the resulting system behavior. The PHY layer simulator is part of an integrated simulation platform including a traffic model to generate realistic mobility of vehicles and a 3D ray-optical model to calculate the multipath propagation channel between transmitter and receiver. Besides deterministic channel modeling by means of ray-optical modeling, the simulator can also be used with stochastic channel models of typical vehicular scenarios. With the aid of this PHY layer simulator and the integrated channel models, the resulting performance of the system in terms of bit and packet error rates of different receiver designs can be analyzed in order to achieve a robust data transmission.
Photo detector IC for Blu-ray-Disc applications: a realization applying efficient design methodologies
Authors: Lange S. , Reich T. , Nowak J. , Dimov B. , Meister M. , Hennig E.
Published: August 2011

Abstract. A high-speed photo detector IC for application in Blu-ray/DVD/CD drives is presented. Bandwidths for the highest gain of 254 MHz and 221 MHz for 405 nm (Blu-ray) and 635 nm (DVD) wavelengths, respectively, were achieved by applying novel design methodologies. The combination of this outstanding speed performance with its low power dissipation of 192 mW at 5V supply and the low noise power of −72 dBm at 300 MHz makes it the best in literature reported optical transceiver IC for Blu-ray and Blu-ray/DVD/CD multi drives. Beside the excellent performance results, the usage of the novel design methodologies gave us an increased design efficiency with 25% compared to earlier similar design processes.
A low power clock generator with adaptive inter-phase charge balancing for variability compensation in 40-nm CMOS
Authors: Schulze U. , Broich M. , Weiss O. , Noll T. G.
Published: August 2011

Abstract. Power dissipation besides chip area is still one main optimization issue in high performance CMOS design. Regarding high throughput building blocks for digital signal processing architectures which are optimized down to the physical level a complementary two-phase clocking scheme (CTPC) is often advantageous concerning ATE-efficiency. The clock system dissipates a significant part of overall power up to more than 50% in some applications. One efficient power saving strategy for CTPC signal generation is the charge balancing technique. To achieve high efficiency with this approach a careful optimization of timing relations within the control is inevitable. However, as in modern CMOS processes device variations increase, timing relations between sensitive control signals can be affected seriously. In order to compensate for the influence of global and local variations in this work, an adaptive control system for charge balancing in a CTPC generator is presented. An adjustment for the degree of charge recycling is performed in each clock cycle. In the case of insufficient recycling the delay elements which define duration and timing position of the recycling pulse are corrected by switchable timing units. In a benchmark with the conventional clock generation system, a power reduction gain of up to 24.7% could be achieved. This means saving in power of more than 12% for a complete number-crunching building block.
Fully-integrated LDO voltage regulator for digital circuits
Authors: Lüders M. , Eversmann B. , Schmitt-Landsiedel D. , Brederlow R.
Published: August 2011

Abstract. Low-dropout (LDO) voltage regulators are widely used to supply low-voltage digital circuits. For recent ultra-low-power microcontroller systems, a fully-integrated LDO without any external capacitance is preferred in order to achieve a fast and energy-efficient wake-up. Commonly, an LDO is specified, designed and verified for DC load currents. In contrast, a digital load creates large current spikes. As an LDO designed for low quiescent current is too slow to react on fast current spikes, a minimum on-chip capacitance is required to keep the supply voltage within a certain error window. Different fully-integrated LDO topologies are investigated regarding their suitability to supply low-voltage digital circuits. The any-load stable LDO topology is selected and implemented on a 0.13 μm test-chip. The LDO is able to provide a maximum load current of 2.5 mA while consuming a quiescent current of 17 μA.
Probabilistic modeling of noise transfer characteristics in digital circuits
Authors: Schleifer J. , Coenen T. , Elkammar A. , Noll T. G.
Published: August 2011

Abstract. Device scaling, the driving force of CMOS technology, led to continuous decrease in the energy level representing logic states. The resulting small noise margins in combination with increasing problems regarding the supply voltage stability and process variability creates a design conflict between efficiency and reliability. This conflict is expected to rise more in future technologies. Current research approaches on fault-tolerance architectures and countermeasures at circuit level, unfortunately, cause a significant area and energy penalty without guaranteeing absence of errors. To overcome this problem, it seems to be attractive to tolerate bit errors at circuit level and employ error handling methods at higher system levels. To do this, an estimate of the bit error rate (BER) at circuit level is necessary. Due to the size of the circuits, Monte Carlo simulation suffers from impractical runtimes. Therefore the needed modeling scheme is proposed. The model allows a probabilistic estimation of error rates at circuit level taking into account statistical effects ranging from supply noise and electromagnetic coupling to process variability within reasonable runtimes.
Evaluation of a concept for density measurement of solid particle flows in pneumatic conveying systems with microwaves (8–12 GHz)
Authors: Baer C. , Musch T. , Gerding M. , Vogt M.
Published: August 2011

Abstract. This paper presents a novel density measuring concept for gas/coal particle compositions in pneumatic conveying systems. The proposed monitoring system uses horn antennas to perform complex electromagnetic transmittance measurements through the cross section of the conveying tube. The phase of the complex transmittance gives information about the effective permittivity, which is related to the mean volume fraction of the coal. Electromagnetic field simulations have been performed for the evaluation of the concept and the performance of the designed setup. A test stand for measurements on coal dust under reproducible conditions and with well-defined particle concentrations has been developed and implemented. The test tube has a diameter of 200 mm and a length of 400 mm. Coal particles with a diameter between 20 μm and 100 μm have been dispersed by injecting nitrogen gas inside the test tube. Complex transmission measurements are performed in the implemented setup with a calibrated vector network analyzer within a frequency range of 8–12 GHz. Results of the conceptual evaluation by measurements with different concentrations of coal particles are presented and discussed.
A CMOS integrated impedance-to-frequency converter for sensing cellular adhesion
Authors: Mucha A. , Schienle M. , Schmitt-Landsiedel D.
Published: August 2011

Abstract. Sensing cellular adhesion via impedance measurements provides a versatile and easily accessible means for monitoring in-vitro cell cultures. Previous works used external electronics connected via cables to microelectrodes to achieve this goal, thus incurring parasitic impedance, electromagnetic interference, and bulky measurement setups. In this work we present a CMOS impedance-to-frequency converter integrated with biocompatible planar surface electrodes to make a compact and robust sensor chip for in-vitro cell monitoring. The system features an 8×8 array of individually addressable electrodes connected to four impedance-to-frequency converter circuits with externally adjustable biasing and square wave output. We present first measurement results obtained with the integrated electronics that demonstrate the successful operation of the system and show good agreement with models of the electrode and cell impedances.
Fault tree analysis for system modeling in case of intentional EMI
Authors: Genender E. , Mleczko M. , Döring O. , Garbe H. , Potthast S.
Published: August 2011

Abstract. The complexity of modern systems on the one hand and the rising threat of intentional electromagnetic interference (IEMI) on the other hand increase the necessity for systematical risk analysis. Most of the problems can not be treated deterministically since slight changes in the configuration (source, position, polarization, ...) can dramatically change the outcome of an event. For that purpose, methods known from probabilistic risk analysis can be applied. One of the most common approaches is the fault tree analysis (FTA). The FTA is used to determine the system failure probability and also the main contributors to its failure. In this paper the fault tree analysis is introduced and a possible application of that method is shown using a small computer network as an example. The constraints of this methods are explained and conclusions for further research are drawn.
Coupling path influence on the conducted emission measurement results by the EMC semiconductor test board
Authors: Frick M. , Eidher R. , Weigel R.
Published: August 2011

Abstract. The fact of reduced development time in the automotive sector requires a change in the electromagnetic compatibility (EMC) validation of electronic components. To increase the development time of automotive components, e.g. sensors or electronic control units (ECUs), it is mandatory to verify the EMC behavior of the integrated circuit (IC) itself in an early development stage simultaneous to the development process of the entire ECU into which it is embedded. The conducted IC EMC tests emission as well as immunity is realized with a specific test printed circuit board (PCB) which is built according to the guidelines of the Bosch, Infineon, Siemens VDO Specification (BISS, 2007). The measurement results of these EMC tests are affected by the test PCB itself. To deduce the application requirements of the component from the application circuit of the test PCB it is necessary to consider this influence by the printed circuit board. The text at hand gives an overview on how far the emission results are adulterated by the used test PCB. The presented method also grants a validation of the disturbance voltage directly at the IC pin considering the application circuit.
Reduction of heat sink common-mode currents in switching mode power supply circuits
Authors: Kulanayagam J. , Hagmann J. H. , Hoffmann K. F. , Dickmann S.
Published: August 2011

Abstract. In this paper, a new filter design for a heat sink is presented. The parasitic couplings between electric power devices and the heat sink are responsible for common-mode currents. The main focus is on the reduction of these currents to reduce the heat sink radiation. For this purpose a new filter design is proposed. In addition, experimental results are shown to validate the proposed filter.
Some anomalies of mesosphere/lower thermosphere parameters during the recent solar minimum
Authors: Jacobi Ch. , Hoffmann P. , Placke M. , Stober G.
Published: August 2011

Abstract. The recent solar minimum has been characterized by an anomalous strong decrease of thermospheric density since 2005. Here we analyze anomalies of mesosphere/lower thermosphere parameters possibly connected with this effect. In particular, nighttime mean LF reflection heights measured at Collm, Germany, show a very strong decrease after 2005, indicating a density decrease. This decrease is also visible in mean meteor heights measured with VHF meteor radar at Collm. This density decrease is accompanied by an increase of gravity wave (GW) amplitudes in the upper mesosphere and a decrease in the lower thermosphere. On the decadal scale, GWs are negatively correlated with the background zonal wind, but this correlation is modulated in the course of the solar cycle, indicating the combined effect of GW filtering and density decrease.
Modeling of field singularities at dielectric edges using grid based methods
Authors: Classen C. , Gjonaj E. , Römer U. , Schuhmann R. , Weiland T.
Published: August 2011

Abstract. Electric field singularities at sharp metallic edges or at a dielectric contact line can be described analytically by asymptotic expressions. The a priori known form of the field distribution in the vicinity of these edges can be used to construct numerical methods with improved accuracy. This contribution focuses on a modified Finite Integration Technique and on a Discontinuous Galerkin Method with singular approximation functions. Both methods are able to handle field singularities at perfectly electric conducting as well as at dielectric edges. The numerical accuracy of these methods is investigated in a number of simulation examples including static and dynamic field problems.
Combined lumped element network and transmission line synthesis for passive microwave structures
Authors: Russer J. A. , Mukhtar F. , Baev A. , Kuznetsov Y. , Russer P.
Published: August 2011

Abstract. Compact circuit models of electromagnetic structures are a valuable tool for embedding distributed circuits into complex circuits and systems. However, electromagnetic structures with large internal propagation delay are described by impedance functions with a large number of frequency poles in a given frequency interval and therefore yielding equivalent circuit models with a high number of lumped circuit elements. The number of circuit elements can be reduced considerably if in addition to capacitors, inductors, resistors and ideal transformers also delay lines are included. In this contribution a systematic procedure for the generation of combined lumped element/delay line equivalent circuit models on the basis of numerical data is described. The numerical data are obtained by numerical full-wave modeling of the electromagnetic structure. The simulation results are decomposed into two parts representing a lumped elements model and a delay line model. The extraction of the model parameters is performed by application of the system identification procedure to the scattering transfer function. Examples for the modeling of electromagnetic structures are presented.
A universal carbonate ion effect on stable oxygen isotope ratios in unicellular planktonic calcifying organisms
Authors: Ziveri P. , Thoms S. , Probert I. , Geisen M. , Langer G.
Published: August 2011

Abstract. The oxygen isotopic composition (δ18O) of calcium carbonate of planktonic calcifying organisms is a key tool for reconstructing both past seawater temperature and salinity. The calibration of paloeceanographic proxies relies in general on empirical relationships derived from experiments on extant species. Laboratory experiments have more often than not revealed that variables other than the target parameter influence the proxy signal, which makes proxy calibration a challenging task. Understanding these secondary or "vital" effects is crucial for increasing proxy accuracy and possibly for developing new biomarkers. We present data from laboratory experiments showing that oxygen isotope fractionation during calcification in the coccolithophore Calcidiscus leptoporus and the calcareous dinoflagellate Thoracosphaera heimii is dependent on carbonate chemistry of seawater in addition to its dependence on temperature. A similar result has previously been reported for planktonic foraminifera, suggesting that the [CO32−] effect on δ18O is universal for unicellular calcifying planktonic organisms. The slopes of the δ18O/[CO32−] relationships range between −0.0243 (μmol kg−1)−1 (calcareous dinoflagellate T. heimii) and the previously published 0.0022 (μmol kg−1)−1 (non-symbiotic planktonic foramifera Orbulina universa), while C. leptoporus has a slope of 0.0048 (μmol kg−1)−1. We present a simple conceptual model, based on the contribution of δ18O-enriched HCO3− to the CO32− pool in the calcifying vesicle, which can explain the [CO32−] effect on δ18O for the different unicellular calcifiers. This approach provides a new insight into biological fractionation in calcifying organisms. The large range in δ18O/[CO32−] slopes should possibly be explored as a means for paleoreconstruction of surface [CO32−], particularly through comparison of the response in ecologically similar planktonic organisms.
MicroRNA down-regulated in human cholangiocarcinoma control cell cycle through multiple targets involved in the G1/S checkpoint
Authors: Olaru Alexandru V. , Ghiaur Gabriel , Yamanaka Sumitaka , Luvsanjav Delgermaa , An Fangmei , Popescu Irinel , Alexandrescu Sorin , Allen Sarah , Pawlik Timothy M. , Torbenson Michael , Georgiades Christos , Roberts Lewis R. , Gores Gregory J. , Ferguson-Smith Anne , Almeida Maria I. , Calin George A. , Mezey Esteban , Selaru Florin M.
Published: August 2011

MicroRNAs (miRs) recently emerged as prominent regulators of cancer processes. In the current study we aimed at elucidating regulatory pathways and mechanisms through which miR-494, one of the miR species found to be down-regulated in cholangiocarcinoma (CCA), participates in cancer homeostasis. miR-494 was identified as down-regulated in CCA based on miR arrays. Its expression was verified with quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). To enforce miR expression, we employed both transfection methods, as well as a retroviral construct to stably overexpress miR-494. Up-regulation of miR-494 in cancer cells decreased growth, consistent with a functional role. mRNA arrays of cells treated with miR-494, followed by pathway analysis, suggested that miR-494 impacts cell cycle regulation. Cell cycle analyses demonstrated that miR-494 induces a significant G1/S checkpoint reinforcement. Further analyses demonstrated that miR-494 down-regulates multiple molecules involved in this transition checkpoint. Luciferase reporter assays demonstrated a direct interaction between miR-494 and the 3′-untranslated region of cyclin-dependent kinase 6 (CDK6). Last, xenograft experiments demonstrated that miR-494 induces a significant cancer growth retardation

in vivo

.

Conclusion:

Our findings demonstrate that miR-494 is down-regulated in CCA and that its up-regulation induces cancer cell growth retardation through multiple targets involved in the G1-S transition. These findings support the paradigm that miRs are salient cellular signaling pathway modulators, and thus represent attractive therapeutic targets. miR-494 emerges as an important regulator of CCA growth and its further study may lead to the development of novel therapeutics. (Hepatology 2011)
Genotypic and phenotypic analysis of variants resistant to hepatitis C virus nonstructural protein 5A replication complex inhibitor BMS-790052 in Humans: In Vitro and In Vivo Correlations
Authors: Fridell Robert A. , Wang Chunfu , Sun Jin-Hua , O'Boyle Donald R. , Nower Peter , Valera Lourdes , Qiu Dike , Roberts Susan , Huang Xin , Kienzle Bernadette , Bifano Marc , Nettles Richard E. , Gao Min
Published: August 2011

The NS5A replication complex inhibitor, BMS-790052, inhibits hepatitis C virus (HCV) replication with picomolar potency in preclinical assays. This potency translated

in vivo

to a substantial antiviral effect in a single-ascending dose study and a 14-day multiple-ascending dose (MAD) monotherapy study. However, HCV RNA remained detectable in genotype 1a–infected patients at the end of the MAD study. In contrast, viral breakthrough was observed less often in patients infected with genotype 1b, and, in several patients, HCV RNA declined and remained below the level of quantitation (<25 IU/mL) through the duration of treatment. Here, we report on the results of the genotypic and phenotypic analyses of resistant variants in 24 genotype 1–infected patients who received BMS-790052 (1, 10, 30, 60, and 100 mg, once-daily or 30 mg twice-daily) in the 14-day MAD study. Sequence analysis was performed on viral complementary DNA isolated from serum specimens collected at baseline and days 1 (4, 8, and 12 hours), 2, 4, 7, and 14 postdosing. Analyses of the sequence variants (1) established a correlation between resistant variants emerging

in vivo

with BMS-790052 treatment and those observed in the

in vitro

replicon system (major substitutions at residues 28, 30, 31, and 93 for genotype 1a and residues 31 and 93 for genotype 1b); (2) determined the prevalence of variants at baseline and the emergence of resistance at different times during dosing; and (3) revealed the resistance profile and replicative ability (i.e., fitness) of the variants.

Conclusion:

Although resistance emerged during monotherapy with BMS-790052, the substantial anti-HCV effect of this compound makes it an excellent candidate for effective combination therapy. (Hepatology 2011)
A New Technique of Locked, Flexible Intramedullary Nailing of Spiral and Comminuted Fractures of the Metacarpals: A Series of 21 Cases
Authors: Agashe Mandar V. , Phadke Sanjay , Agashe Vikas M. , Patankar Hemant
Published: August 2011

Background

Spiral and comminuted fractures of the metacarpals are rotationally and axially unstable fractures with a tendency to shorten, which in turn causes significant extensor lag and loss of grip strength. We have designed a new, cheap and locally developed method of locked intramedullary nailing of these metacarpal fractures. We are presenting the results of our first 21 patients with 22 fractures treated by closed, fluoroscopically assisted, intramedullary K-wiring with proximal locking done by a specially designed locking pin.

Materials and Methods

This was a retrospective, observational cohort study of all patients with spiral and comminuted fractures of metacarpals with minimum of 1 year of follow-up and average follow-up of 14 months (range, 12 to 26 months). The patients were evaluated clinico-radiologically using range of motion, extensor lag, time to healing, amount of collapse, angulation and rotation and complications.

Results

All fractures had healed uneventfully with average time to union being 8 weeks. Average metacarpal shortening was 2.04±0.95 mm, while the average post-operative angulation of the fracture was 4.81°±1.7. The metacarpophalangeal range-of-motion recovered almost fully with the average extensor lag being only 5.22°±2.42. Other than extensor tendinitis in two patients, there were no other complications.

Conclusions

This method is cosmetically appealing, provides stable fixation, avoids periosteal stripping associated with open reduction and is associated with very low complication rate, and thus can be safely and effectively used for the treatment of these difficult fractures.
A Review of the Receptor-Binding Properties ofp-Synephrine as Related to Its Pharmacological Effects
Authors: Stohs Sidney J. , Preuss Harry G. , Shara Mohd
Published: August 2011

Bitter orange (Citrus aurantium) extract and its primary protoalkaloidp-synephrine are used widely in weight loss/weight management and sports performance products. Because of structural similarities, the pharmacological effects ofp-synephrine are widely assumed to be similar to those of ephedrine,m-synephrine (phenylephrine), and endogenous amine neurotransmitters as norepinephrine and epinephrine. However, small structural changes result in the receptor binding characteristics of these amines that are markedly different, providing a plausible explanation for the paucity of adverse effects associated with the wide-spread consumption ofp-synephrine in the form of dietary supplements as well as in variousCitrusfoods and juices. This paper summarizes the adrenoreceptor binding characteristics ofp-synephrine relative tom-synephrine, norepinephrine, and other amines as related to the observed pharmacological effects.
Learning to Be Illegal
Authors: Gonzales Roberto G.
Published: August 2011

This article examines the transition to adulthood among 1.5-generation undocumented Latino young adults. For them, the transition to adulthood involves exiting the legally protected status of K to 12 students and entering into adult roles that require legal status as the basis for participation. This collision among contexts makes for a turbulent transition and has profound implications for identity formation, friendship patterns, aspirations and expectations, and social and economic mobility. Undocumented children move from protected to unprotected, from inclusion to exclusion, from de facto legal to illegal. In the process, they must learn to be illegal, a transformation that involves the almost complete retooling of daily routines, survival skills, aspirations, and social patterns. These findings have important implications for studies of the 1.5- and second-generations and the specific and complex ways in which legal status intervenes in their coming of age. The article draws on 150 interviews with undocumented 1.5-generation young adult Latinos in Southern California.
The effects of diesel contaminants on tribological performance on sliding steel on steel contacts
Authors: Penchaliah R , Harvey T J , Wood R J K , Nelson K , Powrie H E G
Published: August 2011

This article presents the findings from a parametric study examining the effect of four contaminants (soot, oxidation, moisture, and sulphuric acid) at varying levels (four for each). It was observed that all contaminants and contaminant levels reduce the conductivity of the oil. Oxidation and soot contaminants produced large increases in viscosity. The wear rate was mainly influenced by acid and soot additions, while the coefficient of friction was increased by all contaminants and contaminant levels. The steady-state charge levels changed for some contaminants. The best correlation of steady-state charge with the other measured tribological parameters of wear rate, friction, and temperature is seen for the series of oxidized oils. The multi-contaminated oil (L4 × 4) shows remarkably little degradation in tribological performance. Analysis of the wear mechanisms shows that soot and oxidation produced abrasion and polishing wear, respectively, while sulphuric acid and moisture produced corrosive wear.
Intracranial hypertension in 2 cases of craniometaphyseal dysplasia: differing surgical options
Authors: Rivero-Garvía Mónica , Márquez-Rivas F. Javier , García-Iglesias Antonia , Gutiérrez-González Raquel
Published: August 2011

Craniometaphyseal dysplasia (CMD) is a very rare bone disorder characterized by abnormally developed metaphyses in long bones and sclerosis of the craniofacial bones. In this paper, the authors report 2 cases of children diagnosed with CMD and chronic intracranial hypertension with deletion in exon 9 of the human ANK gene (ANKH). After intracranial monitoring, a different treatment was chosen for each patient. One of the patients was treated using CSF shunting because ventriculomegaly in the absence of a Chiari malformation was also observed on cerebral MR imaging. The other patient underwent cranial expansion and decompressive craniotomy of the posterior fossa, because ventriculomegaly was excluded after cerebral MR imaging and cervical MR imaging showed a Chiari malformation Type I. The origin of intracranial hypertension in CMD is multifactorial. Previous intracranial pressure monitoring and a thorough understanding of neuroimaging studies are essential to achieve an accurate diagnosis and effective treatment.
Reconstruction of unicoronal plagiocephaly with a hypercorrection surgical technique
Authors: Mesa John M. , Fang Frank , Muraszko Karin M. , Buchman Steven R.
Published: August 2011

Object

Successful surgical repair of unicoronal plagiocephaly remains a challenge for craniofacial surgeons. Many of the surgical techniques directed at correcting the stigmata associated with this craniofacial deformity (for example, ipsilateral supraorbital rim elevation [vertical dystopia], ipsilateral temporal constriction, C-shaped deformity of the face, and so on) are not long lasting and often result in deficient correction and the need for secondary revision surgery. The authors posit that the cause of this relapse was intrinsic deficiencies of the current surgical techniques. The aim of this study was to determine if correction of unilateral coronal plagiocephaly with a novel hypercorrection surgical technique could prevent the relapse of the characteristics associated with unicoronal plagiocephaly.

Methods

The authors performed a retrospective analysis of 40 consecutive patients who underwent surgical repair of unicoronal plagiocephaly at their institution between 1999 and 2009. In all cases, the senior author (S.R.B.) used a hypercorrection technique for surgical reconstruction. Hypercorrection consisted of significant overcorrection of the affected ipsilateral frontal and anterior temporal areas in the sagittal and coronal planes. Demographic, perioperative, and follow-up data were collected for comparison. The postsurgical appearance of the forehead was documented clinically and photographically and then evaluated and scored by 2 independent graders using the expanded Whitaker scoring system. A relapse was defined as a recurrence of preoperative features that required secondary surgical correction.

Results

The mean age of the patients at the time of the operation was 13 months (range 8–28 months). The mean follow-up duration was 57 months (range 3 months to 9.8 years). The postsurgical hypercorrection appearance persisted on average 6–8 months but gradually dissipated and normalized. No patients exhibited a relapse of unicoronal plagiocephalic characteristics that required surgical correction. In all cases the aesthetic results were excellent. Only 3 patients required reoperation for the management of persistent calvarial bone defects (2 cases) and removal of a symptomatic granuloma (1 case).

Conclusions

Our study demonstrates that patients who undergo unicoronal plagiocephaly repair with a hypercorrection surgical technique avoid long-term relapse. Our results suggest that the surgical technique used in the correction of unilateral coronal synostosis is strongly associated with the prevention of postsurgical relapse and that the use of this novel method decreases the need for surgical revision.
Smoothing techniques for decision-directed MIMO OFDM channel estimation
Authors: Beinschob P. , Zölzer U.
Published: August 2011

Abstract. With the purpose of supplying the demand of faster and more reliable communication, multiple-input multiple-output (MIMO) systems in conjunction with Orthogonal Frequency Division Multiplexing (OFDM) are subject of extensive research. Successful Decoding requires an accurate channel estimate at the receiver, which is gained either by evaluation of reference symbols which requires designated resources in the transmit signal or decision-directed approaches. The latter offers a convenient way to maximize bandwidth efficiency, but it suffers from error propagation due to the dependency between the decoding of the current data symbol and the calculation of the next channel estimate. In our contribution we consider linear smoothing techniques to mitigate error propagation by the introduction of backward dependencies in the decision-based channel estimation. Designed as a post-processing step, frame repeat requests can be lowered by applying this technique if the data is insensitive to latency. The problem of high memory requirements of FIR smoothing in the context of MIMO-OFDM is addressed with an recursive approach that acquires minimal resources with virtual no performance loss. Channel estimate normalized mean square error and bit error rate (BER) performance evaluations are presented. For reference, a median filtering technique is presented that operates on the MIMO time-frequency grids of channel coefficients to reduce the peak-like outliers produced by wrong decisions due to unsuccessful decoding. Performance in terms of Bit Error Rate is compared to the proposed smoothing techniques.
Impacts of land cover and climate data selection on understanding terrestrial carbon dynamics and the CO2 airborne fraction
Authors: Poulter B. , Frank D. C. , Hodson E. L. , Zimmermann N. E.
Published: August 2011

Abstract. Terrestrial and oceanic carbon cycle processes remove ~55 % of global carbon emissions, with the remaining 45 %, known as the "airborne fraction", accumulating in the atmosphere. The long-term dynamics of the component fluxes contributing to the airborne fraction are challenging to interpret, but important for informing fossil-fuel emission targets and for monitoring the trends of biospheric carbon fluxes. Climate and land-cover forcing data for terrestrial ecosystem models are a largely unexplored source of uncertainty in terms of their contribution to understanding airborne fraction dynamics. Here we present results using a single dynamic global vegetation model forced by an ensemble experiment of climate (CRU, ERA-Interim, NCEP-DOE II), and diagnostic land-cover datasets (GLC2000, GlobCover, MODIS). For the averaging period 1996–2005, forcing uncertainties resulted in a large range of simulated global carbon fluxes, up to 13 % for net primary production (52.4 to 60.2 Pg C a−1) and 19 % for soil respiration (44.2 to 54.8 Pg C a−1). The sensitivity of contemporary global terrestrial carbon fluxes to climate strongly depends on forcing data (1.2–5.9 Pg C K−1 or 0.5 to 2.7 ppmv CO2 K−1), but weakening carbon sinks in sub-tropical regions and strengthening carbon sinks in northern latitudes are found to be robust. The climate and land-cover combination that best correlate to the inferred carbon sink, and with the lowest residuals, is from observational data (CRU) rather than reanalysis climate data and with land-cover categories that have more stringent criteria for forest cover (MODIS). Since 1998, an increasing positive trend in residual error from bottom-up accounting of global sinks and sources (from 0.03 (1989–2005) to 0.23 Pg C a−1 (1998–2005)) suggests that either modeled drought sensitivity of carbon fluxes is too high, or that carbon emissions from net land-cover change is too large.
Exploring errors in paleoclimate proxy reconstructions using Monte Carlo simulations: paleotemperature from mollusk and coral geochemistry
Authors: Carré M. , Sachs J. P. , Wallace J. M. , Favier C.
Published: August 2011

Abstract. Reconstructions of the past climate from proxy records involve a wide range of uncertainties at every step of the process. These uncertainties and the subsequent error bar in the reconstruction of a paleoclimatic variable need to be understood and quantified in order to properly interpret the reconstructed variability and to perform meaningful comparisons with climate model outputs. Classic proxy calibration-validation techniques are not well-suited for identifying the causes of reconstruction errors, estimating their relative contribution, or understanding how errors accumulate from a multitude of sources. In this study, we focus on high resolution proxy records based on calcium carbonate geochemistry of sessile organisms such as mollusks, corals, or sclerosponges, and propose an approach based on Monte Carlo simulations with simple numerical surrogate proxies. A freely available algorithm (MoCo, http://www.isem.cnrs.fr/spip.php?rubrique472) is provided for estimating systematic and standard errors of mean temperature, seasonality and variance reconstructed from marine accretionary archive geochemistry. This algorithm is then used for sensitivity experiments in a case study to characterize and quantitatively evaluate the sensitivity of systematic and standard errors to sampling randomness, stochastic uncertainty sources and systematic proxy limitations. The results of the experiments yield an illustrative example of the range of variations that climate reconstruction errors may undergo, and bring to light their complexity. One of the main improvements of this method is the identification and estimation of systematic bias that would not otherwise be detected. It thus offers the possibility of correcting the proxy-based climate from these biases for a more accurate reconstruction. Beyond the findings of error sources for coral and mollusk-based reconstructions, our study demonstrates that numerical simulations based on Monte Carlo analyses are a simple and powerful approach to improve the proxy calibration process. A thourough understanding of the proxy record errors is essential for the interpretation of paleoclimate records from proxies derived from accretionary skeleton geochemistry. The error estimates provided by MoCo are much more comprehensive and therefore closer to reality than error estimates provided by typical calibration studies.
Retinal functional changes measured by microperimetry after immunosuppressive therapy in patients with Vogt-Koyanagi-Harada disease
Authors: El-Asrar Ahmed M. Abu , Al-Mezaine Hani S. , Hemachandran Suhail , Hariz Rajab , Kangave Dustan
Published: August 2011

Purpose

To evaluate the effect of immunosuppressive therapy on best-corrected visual acuity (BCVA), fixation stability, and central retinal sensitivity in patients with Vogt-Koyanagi-Harada (VKH) disease in the acute uveitic phase.

Methods

In this prospective study, 14 patients (28 eyes) were evaluated. Best-corrected visual acuity and MP-1 microperimetric evaluation of retinal sensitivity in the central 12 degrees and fixation stability were assessed at baseline and at 1, 3, 6, 9, and 12 months after treatment.

Results

At baseline, logarithm of the minimum angle of resolution (logMAR) BCVA, fixation stability, and mean retinal sensitivity levels were 0.685±0.6 (Snellen equivalent, 20/100), 61.2%±29.0%, and 2.75±3.8 dB, respectively. At 3 months, logMAR BCVA (0.11±0.2, Snellen equivalent 20/25) and fixation stability (86.4%±13.4%) were almost maximum (p<0.001 for both comparisons), and thereafter remained almost unchanged. Mean retinal sensitivity continued to improve up to 12 months (12.0±2.3 dB, p<0.001); however, it was still significantly decreased. There were significant correlations between logMAR BCVA and mean retinal sensitivity at all time points. The percentages of BCVA improvement were significantly higher than the percentages of mean retinal sensitivity improvement at all time points (p<0.001 for all comparisons).

Conclusions

Compared with microperimetry, BCVA significantly underestimates macular dysfunction in VKH disease.
Shift–Share Analysis to Measure Arrivals Competitiveness: The Case of Vietnam, 1995–2007
Authors: Vu Jo , Turner Lindsay
Published: August 2011

Vietnam has been recognized as a significant new tourist arrivals market in Asia. This study examines tourist arrivals in Vietnam compared with Thailand and China from 1995 to 2007. Shift–share analysis is used to test whether the emerging Vietnam market is impacting on the growth of the Thai or China markets. The findings indicate that shift–share analysis is a useful management tool when applied to measuring the competitive effect between rival markets. This analysis shows that Vietnam is increasingly specialized in attracting tourists from the Americas, Australasia and Europe, and that it has a competitive advantage over Thailand. It is also interesting to note that, since 1995, Vietnam increasingly has been losing ground in attracting more tourists from neighbouring Asian countries.
Animal Models of Mycobacteria Infection
Authors: Ordway Diane J. , Orme Ian M.
Published: August 2011

This unit describes the infection of mice and guinea pigs with mycobacteria via various routes, as well as necropsy methods for the determination of mycobacterial loads within target organs. Additionally, methods for cultivating mycobacteria and preparing stocks are described. The protocols outlined are primarily used for M. tuberculosis, but can also be used for the study of other non‐tuberculosis mycobacterial species. Curr. Protoc. Immunol. 94:19.5.1‐19.5.50. © 2011 by John Wiley & Sons, Inc.
Genetic Screens and Biochemical Assays to Characterize Vibrio cholerae O1 Biotypes: Classical and El Tor
Authors: Son Mike S. , Taylor Ronald K.
Published: August 2011

Vibrio cholerae serogroup O1 has two biotypes, classical and El Tor, the latter of which has displaced the prior and has been the causative agent for the ongoing seventh pandemic. However, reports since 2001 have identified clinical isolates of El Tor that have classical O1 biotype genetic and phenotypic characteristics. These El Tor variants have been emerging in clinical settings with increased frequency, including the 2010 cholera outbreak in Haiti. The emergence of El Tor variants warrants the proper and timely identification of clinical (or environmental) isolates' biotype. This unit describes some quick and simple genetic screens and phenotypic assays (biochemical characterization), to be performed simultaneously, commonly used to distinguish biotype and initiate characterization of any clinical (or environmental) isolates of Vibrio cholerae O1. Curr. Protoc. Microbiol. 22:6A.2.1‐6A.2.17. © 2011 by John Wiley & Sons, Inc.
Screening of Hepatitis C Virus Inhibitors Using Genotype 1a HCV Replicon Cell Lines
Authors: Robinson Margaret , Tian Yang , Pagratis Nikos , Delaney William E.
Published: August 2011

Hepatitis C virus (HCV) replicons are the primary tools for identifying and evaluating anti‐HCV compounds during drug discovery research. Genotype 1a and 1b are the most common genotypes in North America and Europe. These genotypes display significant genetic divergence (∼20% at the nucleotide level and ∼14% at the amino acid level), which can translate into marked differences in drug susceptibility. Thus, it is critical that potential therapeutics be assessed against both genotypes to ensure antiviral efficacy in the broad genotype 1 patient population. This unit describes assays for screening HCV inhibitors using replicons with a focus on genotype 1a. Specific protocols are provided for screening 1a replicons that encode the Renilla luciferase gene and for replicons that do not encode exogenous reporter genes, both in 96‐well (manual) and in 384‐well (high‐throughput) formats. Curr. Protoc. Microbiol. 22:17.1.1‐17.1.29. © 2011 by John Wiley & Sons, Inc.
Confidence–Accuracy Calibration with General Knowledge and Eyewitness Memory Cued Recall Questions
Authors: Luna Karlos , Martín‐Luengo Beatriz
Published: August 2011

Summary: The confidence–accuracy relationship has primarily been studied through recognition tests and correlation analysis. However, cued recall is more ecological from a forensic perspective. Moreover, there may be more informative ways of analysing the confidence–accuracy relationship than correlations. In the present study, participants viewed a video of a bank robbery and were asked cued recall questions covering general knowledge and the video itself. Confidence ratings were collected, and correlations, calibration and discrimination measures were calculated. All measures indicated a strong confidence–accuracy relationship that was better for general knowledge than eyewitness memory questions. However, there were no differences in confidence ratings for correct answers, suggesting that the differences could be limited to the evaluation of incorrect answers. We concluded that confidence may be a good marker for accuracy with cued recall, but that further research using ecological tests and more informative data analysis techniques is needed. Copyright © 2011 John Wiley & Sons, Ltd.
Evolution of the Dinosauriform Respiratory Apparatus: New Evidence from the Postcranial Axial Skeleton
Authors: Schachner Emma R. , Farmer C.G. , McDonald Andrew T. , Dodson Peter
Published: August 2011

Examination of the thoracic rib and vertebral anatomy of extant archosaurs indicates a relationship between the postcranial axial skeleton and pulmonary anatomy. Lung ventilation in extant crocodilians is primarily achieved with a hepatic piston pump and costal rotation. The tubercula and capitula of the ribs lie on the horizontal plane, forming a smooth thoracic “ceiling” facilitating movement of the viscera. Although the parietal pleura is anchored to the dorsal thoracic wall, the dorsal visceral pleura exhibits a greater freedom of movement. The air sac system and lungs of birds are associated with bicapitate ribs with a ventrally positioned capitular articulation, generating a rigid and furrowed rib cage that minimizes dorsoventral changes in volume in the dorsal thorax. The thin walled bronchi are kept from collapsing by fusion of the lung to the thorax on all sides. Data from this study suggest a progression from a dorsally rigid, heterogeneously partitioned, multichambered lung in basal dinosauriform archosaurs towards the small entirely rigid avian‐style lung that was likely present in saurischian dinosaurs, consistent with a constant volume cavum pulmonale, thin walled parabronchi, and distinct air sacs. There is no vertebral evidence for a crocodilian hepatic piston pump in any of the taxa reviewed. The evidence for both a rigid lung and unidirectional airflow in dinosauriformes raises the possibility that these animals had a highly efficient lung relative to other Mesozoic vertebrates, which may have contributed to their successful radiation during this time period. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Quantitative Assessment of Macrophages in the Muscularis Externa of Mouse Intestines
Authors: Mikkelsen H.B. , Larsen J.O. , Froh P. , Nguyen T.H.
Published: August 2011

Quantification of intestinal cells is challenging for several reasons: The cell densities vary throughout the intestines and may be age dependent. Some cell types are ramified and/or can change shape and size. Additionally, immunolabeling is needed for the correct identification of cell type. Immunolabeling is dependent on both up‐ and down‐regulation of the antigen being labeled as well as on the primary and secondary antibodies, the fixation, and the enhancement procedures. Here, we provide a detailed description of immunolabeling of CD169+ cells and major histocompatibility class II antigen (MHCII+) cells and the subsequent quantification of these cells using design‐based stereology in the intestinal muscularis externa. We used young (5‐weeks‐old) and adult (10‐weeks‐old) mice. Cell densities were higher in jejunum‐ileum, when compared with colon. In jejunum/ileum, the cell densities increased in oral‐anal direction in adults, whereas the densities were highest in the midpart in young animals. In colon, the cell densities decreased in oral‐anal direction in both groups of animals. Except for the density of MHCII+ cells in colon, the cell densities were highest in young animals. Densities of CD169+ and MHCII+ cells did not differ, except in the colon of young animals where the CD169+ density was almost twice as high as the MHCII+ density. CD169 and MHCII antigens seem to be expressed simultaneously by the same cell in jejunum/ileum. We conclude that cell densities depend on both the age of the mouse and on the location in the intestines. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.