bluuebunny/crossref_metadata_2025 huggingface dataset:
A point‐source reconstruction from concentration measurements in low‐wind stable conditions
Authors: Sharan Maithili , Issartel Jean‐Pierre , Singh Sarvesh Kumar
Published: March 2012

An inversion technique is proposed to reconstruct an elevated point emission source of known height of atmospheric trace species from a finite number of concentration measurements in low‐wind stable conditions. Observations from the SF6 diffusion experiment at Idaho National Engineering Laboratory in low‐wind stable conditions are used for the point source reconstruction.

The source location and its strength are both retrieved exactly with the model‐generated measurements in all the runs. With real data, the location is reconstructed with an average error of 20 m, mostly along the wind, and the intensity is retrieved within a factor of 2 in all the runs. The incurred errors in the retrieval are justified by estimating the angular departure between the vectors of measurement and adjoint function. A sensitivity study is carried out to analyse the sensitivity of the source estimation with respect to signal perturbation caused by the background concentration of the species in the ambient air. Source reconstruction is shown to be improved and more focused when the samplers having a measurement value corresponding to the background concentration are maintained in the inversion process. Copyright © 2012 Royal Meteorological Society
Matrix‐assisted laser desorption/ionization mass spectrometric investigation of pollen and their classification by multivariate statistics
Authors: Krause Benjamin , Seifert Stephan , Panne Ulrich , Kneipp Janina , Weidner Steffen M.
Published: March 2012

RATIONALE

A fast and reliable online identification of pollen is not yet available. The identification of pollen is based mainly on the evaluation of morphological data obtained by microscopic methods.

METHODS

Matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐TOF MS) was applied to the analysis of extracts and milled pollen samples. The obtained MALDI data were explored for characteristic peak patterns which could be subjected to a multivariate statistical analysis.

RESULTS

Two sample preparation methods are presented, which require only minimal or no chemical extraction of the pollen. MALDI pollen spectra could be recorded showing various peak patterns. A multivariate statistics approach allowed the classification of pollen into clusters indicating similarities and differences between various species.

CONCLUSIONS

These results demonstrate the potential and the reliability of MALDI‐TOF MS for the identification and, in combination with multivariate statistics, also for the classification of pollen. Copyright © 2012 John Wiley & Sons, Ltd.
Robust output tracking control for a velocity‐sensorless vertical take‐off and landing aircraft with input disturbances and unmatched uncertainties
Authors: Su Shanwei , Lin Yan
Published: March 2012

In this paper, we develop a nonlinear controller to achieve output tracking for a nonminimum phase vertical take‐off and landing aircraft without velocity measurements. To attenuate the effects of input disturbances and unmatched uncertainties, auxiliary control inputs are introduced in the state observer. Then by taking the aircraft lateral movement into consideration, a control law is proposed to force the vertical take‐off and landing aircraft to asymptotically track the desired trajectories even in the presence of unexpected changes of the trajectories, while driving the unstable internal dynamics to follow the bounded and causal ideal internal dynamics via the stable system center method. Numerical simulation results illustrate the effectiveness and robustness of the proposed controller. Copyright © 2012 John Wiley & Sons, Ltd.
Testing superiority at interim analyses in a non‐inferiority trial
Authors: Joshua Chen Y.H. , Chen Cong
Published: March 2012

Shift in research and development strategy from developing follow‐on or ‘me‐too’ drugs to differentiated medical products with potentially better efficacy than the standard of care (e.g., first‐in‐class, best‐in‐class, and bio‐betters) highlights the scientific and commercial interests in establishing superiority even when a non‐inferiority design, adequately powered for a pre‐specified non‐inferiority margin, is appropriate for various reasons. In this paper, we propose a group sequential design to test superiority at interim analyses in a non‐inferiority trial. We will test superiority at the interim analyses using conventional group sequential methods, and we may stop the study because of better efficacy. If the study fails to establish superior efficacy at the interim and final analyses, we will test the primary non‐inferiority hypothesis at the final analysis at the nominal level without alpha adjustment. Whereas superiority/non‐inferiority testing no longer has the hierarchical structure in which the rejection region for testing superiority is a subset of that for testing non‐inferiority, the impact of repeated superiority tests on the false positive rate and statistical power for the primary non‐inferiority test at the final analysis is essentially ignorable. For the commonly used O'Brien–Fleming type alpha‐spending function, we show that the impact is extremely small based upon Brownian motion boundary‐crossing properties. Numerical evaluation further supports the conclusion for other alpha‐spending functions with a substantial amount of alpha being spent on the interim superiority tests. We use a clinical trial example to illustrate the proposed design. Copyright © 2012 John Wiley & Sons, Ltd.
Confidence intervals and statistical testing for ratio measures of percent change
Authors: Winston Carla A. , Hill Andrew N. , Chen Michael P. , Shang Nong , Becerra José E.
Published: March 2012

In public health and medical research, ratio measures of percent change relative to baseline are often used to express a change in disease incidence. Estimating variance becomes more complex when the comparison is to an expectation based on previous data (E), rather than to an observed value (O). In 2009, the decline in reported tuberculosis (TB) cases was the largest single‐year decrease since national TB surveillance began in 1953. To investigate the 2009 TB decline compared with expected counts, we analyzed TB cases reported to the Center for Disease Control and Prevention's National Tuberculosis Surveillance System. We log‐transformed case counts for 2000–2008, and performed linear regression stratified by patient and clinical characteristics. We calculated relative declines from expectation as (O − E) ∕ E for patient subgroups, and constructed 95% confidence intervals for TB declines. We then formulated a Z‐score test statistic comparing declines across patient subgroups under the null hypothesis that the difference of the two ratio measures was zero. We illustrate our methods by comparing 2009 declines from expectation for US‐born versus foreign‐born patients. Predicted values and confidence intervals assessed the magnitude of unexpected TB declines within patient groups, while statistical tests comparing ratio measures evaluated relative TB declines across groups. Published 2012. This article is a US Government work and is in the public domain in the USA.
A smoothing expectation and substitution algorithm for the semiparametric accelerated failure time frailty model
Authors: Johnson Lynn M. , Strawderman Robert L.
Published: March 2012

This paper proposes an estimation procedure for the semiparametric accelerated failure time frailty model that combines smoothing with an Expectation and Maximization‐like algorithm for estimating equations. The resulting algorithm permits simultaneous estimation of the regression parameter, the baseline cumulative hazard, and the parameter indexing a general frailty distribution. We develop novel moment‐based estimators for the frailty parameter, including a generalized method of moments estimator. Standard error estimates for all parameters are easily obtained using a randomly weighted bootstrap procedure. For the commonly used gamma frailty distribution, the proposed algorithm is very easy to implement using widely available numerical methods. Simulation results demonstrate that the algorithm performs very well in this setting. We re‐analyz several previously analyzed data sets for illustrative purposes. Copyright © 2012 John Wiley & Sons, Ltd.
Assessment of skewed exposure in case‐control studies with pooling
Authors: Whitcomb Brian W. , Perkins Neil J. , Zhang Zhiwei , Ye Aijun , Lyles Robert H.
Published: March 2012

Pooling‐based strategies that combine samples from multiple participants for laboratory assays have been proposed for epidemiologic investigations of biomarkers to address issues including cost, efficiency, detection, and when minimal sample volume is available. A modification of the standard logistic regression model has been previously described to allow use with pooled data; however, this model makes assumptions regarding exposure distribution and logit‐linearity of risk (i.e., constant odds ratio) that can be violated in practice. We were motivated by a nested case‐control study of miscarriage and inflammatory factors with highly skewed distributions to develop a more flexible model for analysis of pooled data. Using characteristics of the gamma distribution and the relation between models of binary outcome conditional on exposure and of exposure conditional on outcome, we use a modified logistic regression to accommodate nonlinearity because of unequal shape parameters in gamma distributed exposure for cases and controls. Using simulations, we compare our approach with existing methods for logistic regression for pooled data considering: (1) constant and dose‐dependent effects; (2) gamma and log‐normal distributed exposure; (3) effect size; and (4) the proportions of biospecimens pooled. We show that our approach allows estimation of odds ratios that vary with exposure level, yet has minimal loss of efficiency compared with existing approaches when exposure effects are dose‐invariant. Our model performed similarly to a maximum likelihood estimation approach in terms of bias and efficiency, and provides an easily implemented approach for estimation with pooled biomarker data when effects may not be constant across exposure. Copyright © 2012 John Wiley & Sons, Ltd.
Atomic Structural Analysis of Nanowire Defects and Polytypes Enabled Through Cross‐Sectional Lattice Imaging
Authors: Hemesath Eric R. , Schreiber Daniel K. , Kisielowski Christian F. , Petford‐Long Amanda K. , Lauhon Lincoln J.
Published: March 2012

Correlated transmission electron microscopy imaging, electron diffraction, and Raman spectroscopy are used to investigate the structure of Si nanowires with planar defects. In addition to plan‐view imaging, individual defective nanowires are imaged in axial cross‐section at specific locations selected in plan‐view imaging. This correlated characterization approach enables definitive identification of complex defect structures that give rise to diffraction patterns that have been misinterpreted in the literature. Conclusive evidence for the 9R Si polytype is presented, and the atomic structure of this phase is correlated with kinematically‐forbidden reflections in Si diffraction patterns. Despite striking similarities between imaging and diffraction data from twinned nanowires and the 9R polytype, clear distinctions between the structures can be made. Finally, the structural origins of ⅓{422} reflections in Si [111] diffraction patterns are identified.
X-Ray-Visible Microcapsules Containing Mesenchymal Stem Cells Improve Hind Limb Perfusion in a Rabbit Model of Peripheral Arterial Disease
Authors: Kedziorek Dorota A. , Hofmann Lawrence V. , Fu Yingli , Gilson Wesley D. , Cosby Kenyatta M. , Kohl Bernard , Barnett Brad P. , Simons Brian W. , Walczak Piotr , Bulte Jeff W.M. , Gabrielson Kathleen , Kraitchman Dara L.
Published: March 2012

The therapeutic goal in peripheral arterial disease (PAD) patients is to restore blood flow to ischemic tissue. Stem cell transplantation offers a new avenue to enhance arteriogenesis and angiogenesis. Two major problems with cell therapies are poor cell survival and the lack of visualization of cell delivery and distribution. To address these therapeutic barriers, allogeneic bone marrow-derived mesenchymal stem cells (MSCs) were encapsulated in alginate impregnated with a radiopaque contrast agent (MSC-Xcaps.) In vitro MSC-Xcap viability by a fluorometric assay was high (96.9% ± 2.7% at 30 days postencapsulation) and as few as 10 Xcaps were visible on clinical x-ray fluoroscopic systems. Using an endovascular PAD model, rabbits (n = 21) were randomized to receive MSC-Xcaps (n = 6), empty Xcaps (n = 5), unencapsulated MSCs (n = 5), or sham intramuscular injections (n = 5) in the ischemic thigh 24 hours postocclusion. Immediately after MSC transplantation and 14 days later, digital radiographs acquired on a clinical angiographic system demonstrated persistent visualization of the Xcap injection sites with retained contrast-to-noise. Using a modified TIMI frame count, quantitative angiography demonstrated a 65% improvement in hind limb perfusion or arteriogenesis in MSC-Xcap-treated animals versus empty Xcaps. Post-mortem immunohistopathology of vessel density by anti-CD31 staining demonstrated an 87% enhancement in angiogenesis in Xcap-MSC-treated animals versus empty Xcaps. MSC-Xcaps represent the first x-ray-visible cellular therapeutic with enhanced efficacy for PAD treatment.

Disclosure of potential conflicts of interest is found at the end of this article.
Stochastic weather generators for climate‐change downscaling, part II: multivariable and spatially coherent multisite downscaling
Authors: Wilks Daniel S.
Published: March 2012

This paper continues Part I (Wilks DS. Use of stochastic weather generators for precipitation downscaling. WIRES Clim Change 2010, 1(6):898–907) of a two‐part review on statistical downscaling of climate changes using parametric ‘weather generators’, which treated only precipitation downscaling at individual locations. Here the review is extended to include also downscaling of nonprecipitation variables at individual locations, and spatially coherent precipitation and nonprecipitation downscaling. Parametric weather generators are explicitly stochastic models that usually operate on the daily timescale. The use of stochastic methods for climate downscaling is natural and logically consistent because of the inherent indeterminacy of the problem: any number of small‐scale weather sequences may be associated with a given set of larger‐scale values. Downscaled climate changes are simulated by adjusting or varying the parameters of the weather generators, in a manner consistent with dynamically simulated or otherwise assumed larger‐scale climate changes. Two main approaches for such parametric adjustments have been developed, namely changes in the daily weather generator parameters based on imposed or assumed changes in the corresponding monthly statistics, and day‐by‐day changes to the generator parameters that are controlled by daily variations in simulated atmospheric circulation. These methods are reviewed here, and perspectives on their relative merits are offered. WIREs Clim Change 2012 DOI: 10.1002/wcc.167

This article is categorized under:

Assessing Impacts of Climate Change > Representing Uncertainty
Bezafibrate lowers very long‐chain fatty acids in X‐linked adrenoleukodystrophy fibroblasts by inhibiting fatty acid elongation
Authors: Engelen Marc , Schackmann Martin J. A. , Ofman Rob , Sanders Robert‐Jan , Dijkstra Inge M. E. , Houten Sander M. , Fourcade Stéphane , Pujol Aurora , Poll‐The Bwee Tien , Wanders Ronald J. A. , Kemp Stephan
Published: March 2012

X‐linked adrenoleukodystrophy (X‐ALD) is caused by mutations in the ABCD1 gene encoding ALDP, an ATP‐binding‐cassette (ABC) transporter located in the peroxisomal membrane. ALDP deficiency results in impaired peroxisomal β‐oxidation and the subsequent accumulation of very long‐chain fatty acids (VLCFA; > C22:0) in plasma and tissues. VLCFA are primarily derived from endogenous synthesis by ELOVL1. Therefore inhibiting this enzyme might constitute a feasible therapeutic approach. In this paper we demonstrate that bezafibrate, a PPAR pan agonist used for the treatment of patients with hyperlipidaemia reduces VLCFA levels in X‐ALD fibroblasts. Surprisingly, the VLCFA‐lowering effect was independent of PPAR activation and not caused by the increase in either mitochondrial or peroxisomal fatty acid β‐oxidation capacity. In fact, our results show that bezafibrate reduces VLCFA synthesis by decreasing the synthesis of C26:0 through a direct inhibition of fatty acid elongation activity. Taken together, our data indicate bezafibrate as a potential pharmacotherapeutic treatment for X‐ALD. A clinical trial is currently ongoing to evaluate the effect in patients with X‐ALD.
Exom-Sequenzierung zur Identifizierung von Krankheitsgenen
Authors: Neveling K. , Hoischen A.
Published: March 2012

Neueste Sequenziertechnologien („next-generation sequencing“) erlauben die gleichzeitige Sequenzierung aller proteinkodierender Sequenzen, das sog. Exom. Die Identifizierung der jeweiligen pathogenen Mutation unter den Tausenden detektierten Varianten stellt dabei eine große Herausforderung dar, und neue Strategien für die Priorisierung von Varianten sind unerlässlich. Die jeweilige Wahl einer Strategie ist dabei von verschiedenen Faktoren abhängig, wie z. B. dem Vorhandensein gut charakterisierter Patienten und deren Familien, von der Art der Vererbung, der Schwere der Krankheit sowie deren Frequenz in der allgemeinen Bevölkerung. In dem vorliegenden Übersichtsartikel diskutieren wir die heute gebräuchlichen Strategien zur Identifizierung von neuen Krankheitsgenen mittels Exom-Sequenzierung und beschreiben die Lehren der ersten Exom-Studien. Wir glauben, dass die Sequenzierung von Exomen in den folgenden Jahren die am häufigsten angewandte Methode zur Identifizierung von Krankheitsgenen sein wird und dabei gleichzeitig auch ein großes diagnostisches Potenzial aufweist.
Das 2q37-Deletionssyndrom
Authors: Villavicencio-Lorini P. , Klopocki E. , Pfeiffer L. , Mundlos S. , Horn D.
Published: March 2012

Durch Deletionen im chromosomalen Bereich 2q37 wird ein klinisches Bild verursacht, das als „Albright-hereditäre-Osteodystrophie(AHO)-ähnliches Syndrom“ bezeichnet wird. Aufgrund der Hauptmerkmale leichte bis mäßig schwere Entwicklungsverzögerung, Verhaltensauffälligkeiten und Brachydakytlie Typ E wird dieser Phänotyp auch Brachydaktylie-mentales-Retardierungs-Syndrom (BDMR, MIM 600430) genannt. Durch Eingrenzung minimaler krankheitsrelevanter 2q37-Deletionsintervalle wurde das Histondeacetylase-4-Gen (HDAC4, MIM 605314), ein zentraler Transkriptionsrepressor, der in der Gehirn-, Muskel- und Skelettentwicklung involviert ist, als krankheitsrelevantes Gen für das BDMR-Syndrom identifiziert. Bislang wurden intragenische HDAC4-Mutationen bei 2 Patienten mit BDMR-Syndrom nachgewiesen, bei denen zunächst aufgrund von Verhaltensauffälligkeiten klinisch ein Smith-Magenis-Syndrom vermutet worden war. Untersuchungen mittels Array-CGH („comparative genomic hybridization“) decken ein breiteres phänotypisches Spektrum des 2q37-Deletionssyndroms als bislang bekannt auf. So war der Nachweis einer 2q37-Deletion auch bei entwicklungsverzögerten Patienten ohne BDE möglich.
The crystal structure of the MPN domain from the COP9 signalosome subunit CSN6
Authors: Zhang Heng , Gao Zeng-Qiang , Wang Wen-Jia , Liu Guang-Feng , Shtykova Eleonora V. , Xu Jian-Hua , Li Lan-Fen , Su Xiao-Dong , Dong Yu-Hui
Published: March 2012

CSN6
and
CSN6
bind by x ray scattering (
View interaction
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Awareness of and attitudes toward congenital cytomegalovirus infection among pregnant women in Singapore
Authors: Lim S.L. , Tan W.C. , Tan L.K.
Published: March 2012

Objective

To assess the level of awareness of congenital cytomegalovirus (CMV) infection and attitudes toward prenatal CMV serologic testing among pregnant women.

Methods

A questionnaire was distributed to pregnant women who attended a specialist outpatient clinic at Singapore General Hospital, Singapore, between September and December 2010.

Results

Among 200 respondents, 40 (20.0%) were aware of CMV. Healthcare workers were more likely to be aware of CMV (odds ratio 6.91, confidence interval 2.14–22.30; P = 0.001). Most respondents found it “very” or “somewhat” easy to adhere to standard guidelines for primary prevention of CMV. Among the respondents, 62.0% (124/200) would like to be given the option of prenatal CMV screening and 72.0% (144/200) were keen to be screened. On multivariate analysis, respondents who were keen to undergo serologic screening for CMV were not more likely to consider invasive testing or termination of pregnancy should the test results demonstrate primary maternal CMV infection.

Conclusion

Pregnant women who were keen to undergo CMV testing demonstrated attitudes toward invasive testing and termination of pregnancy that were not significantly different from those of women who would refuse testing. Patient choice and expectations should be considered in the implementation of preventive measures against congenital CMV.
Influence of early self‐diagnosis and treatment of bacterial vaginosis on preterm birth rate
Authors: Sungkar Ali , Purwosunu Yuditiya , Aziz Muhamad F. , Pratomo Hadi , Sutrisna Bambang , Sekizawa Akihiko
Published: March 2012

Objective

To assess whether early self‐diagnosis and treatment of bacterial vaginosis (BV) could lower the preterm birth rate among a group of Indonesian women.

Methods

A randomized controlled trial of 331 pregnant women (14–18 weeks) was conducted. Participants were randomly assigned to either the active model group (n = 176) or the control group (n = 155). Women in the active model group were equipped with a kit to self‐evaluate vaginal pH; those with a positive test result were treated with a twice daily dose of 500 mg of metronidazole for 7 days. The primary end point was preterm birth rate.

Results

There were 6 (3.8%) and 8 (5.4%) preterm births in the active model and control groups, respectively (P = 0.468). No spontaneous abortions were recorded in either group. When compared with the gold standard (Gram staining), the vaginal acidity test had low ability to detect BV, with 88.7% specificity and 36.9% sensitivity. The positive predictive value of the test was 35.0% PPV, while the negative predictive value was 89.4%.

Conclusion

Early self‐diagnosis and treatment of BV did not reduce the preterm birth rate of the study group.

ClinicalTrial.gov number: NCT01232192.
Effects of transvaginal repair of symptomatic rectocele on symptom‐specific distress and impact on quality of life
Authors: Polin Michael R. , Gleason Jonathan L. , Szychowski Jeff M. , Holley Robert L. , Richter Holly E.
Published: March 2012

Objective

To determine symptom‐specific distress and quality‐of‐life impact outcomes among women who had undergone transvaginal repair of symptomatic rectocele.

Methods

Women who underwent transvaginal repair of symptomatic rectocele at the University of Alabama at Birmingham, USA, between April 2006 and June 2009 were included in a retrospective case series. Minimum follow‐up was 1 year post‐surgery. Women who underwent concomitant surgery, other than perineoplasty and/or midurethral sling, were excluded. End points were assessed using the Pelvic Floor Distress Inventory (PFDI‐20) and the Pelvic Floor Impact Questionnaire (PFIQ‐7).

Results

Overall, 113 women underwent repair of symptomatic rectocele, of whom 69 (61.1%) completed preoperative questionnaires and 66 (58.4%) responded to follow‐up questionnaires. Mean time from surgery was 31.2 ± 11.2 months. PFDI‐20 and PFIQ‐7 scores were significantly improved following surgery, with a median pre‐ and post‐surgery difference of 35.4 (P < 0.001) and 31.0 (P = 0.002), respectively.

Conclusion

Patients who underwent transvaginal repair of symptomatic rectocele reported improvements in symptom‐specific distress and impact on quality of life.
Distinct Contributions of Replication and Transcription to Mutation Rate Variation of Human Genomes
Authors: Cui Peng , Ding Feng , Lin Qiang , Zhang Lingfang , Li Ang , Zhang Zhang , Hu Songnian , Yu Jun
Published: March 2012

Here, we evaluate the contribution of two major biological processes—DNA replication and transcription—to mutation rate variation in human genomes. Based on analysis of the public human tissue transcriptomics data, high-resolution replicating map of Hela cells and dbSNP data, we present significant correlations between expression breadth, replication time in local regions and SNP density. SNP density of tissue-specific (TS) genes is significantly higher than that of housekeeping (HK) genes. TS genes tend to locate in late-replicating genomic regions and genes in such regions have a higher SNP density compared to those in early-replication regions. In addition, SNP density is found to be positively correlated with expression level among HK genes. We conclude that the process of DNA replication generates stronger mutational pressure than transcription-associated biological processes do, resulting in an increase of mutation rate in TS genes while having weaker effects on HK genes. In contrast, transcription-associated processes are mainly responsible for the accumulation of mutations in highly-expressed HK genes.
SMS 2.0: An Updated Database to Study the Structural Plasticity of Short Peptide Fragments in Non-Redundant Proteins
Authors: Ravella Dheeraj , Kumar Muthukumarasamy Uthaya , Sherlin Durairaj , Shankar Mani , Vaishnavi Marthandan Kirti , Sekar Kanagaraj
Published: March 2012

The function of a protein molecule is greatly influenced by its three-dimensional (3D) structure and therefore structure prediction will help identify its biological function. We have updated Sequence, Motif and Structure (SMS), the database of structurally rigid peptide fragments, by combining amino acid sequences and the corresponding 3D atomic coordinates of non-redundant (25%) and redundant (90%) protein chains available in the Protein Data Bank (PDB). SMS 2.0 provides information pertaining to the peptide fragments of length 5-14 residues. The entire dataset is divided into three categories, namely, same sequence motifs having similar, intermediate or dissimilar 3D structures. Further, options are provided to facilitate structural superposition using the program structural alignment of multiple proteins (STAMP) and the popular JAVA plug-in (Jmol) is deployed for visualization. In addition, functionalities are provided to search for the occurrences of the sequence motifs in other structural and sequence databases like PDB, Genome Database (GDB), Protein Information Resource (PIR) and Swiss-Prot. The updated database along with the search engine is available over the World Wide Web through the following URL http://cluster.physics.iisc.ernet.in/sms/.
Magnetohydrodynamic drift equations: from Langmuir circulations to magnetohydrodynamic dynamo?
Authors: Vladimirov V. A.
Published: March 2012

We derive the closed system of averaged magnetohydrodynamic (MHD) equations for general oscillating flows. The used small parameter of our asymptotic theory is the dimensionless inverse frequency, and the leading term for a velocity field is chosen to be purely oscillating. The employed mathematical approach combines the two-timing method and the notion of a distinguished limit. The properties of commutators are used to simplify calculations. The derived averaged equations are similar to the original MHD equations, but surprisingly (instead of the commonly expected Reynolds stresses) a drift velocity plays a part of an additional advection velocity. In the special case of a vanishing magnetic field $\mathbi{h}\equiv 0$, the averaged equations produce the Craik–Leibovich equations for Langmuir circulations (which can be called ‘vortex dynamo’). We suggest that, since the mathematical structure of the full averaged equations for $\mathbi{h}\not = 0$ is similar to those for $\mathbi{h}\equiv 0$, these full equations could lead to a possible mechanism of MHD dynamo, such as the generation of the magnetic field of the Earth.
On the Calculation of Two-Dimensional Added Mass Coefficients by the Taylor Theorem and the Method of Fundamental Solutions
Authors: Yang F.-L. , Wu C. T. , Young D. L.
Published: March 2012

This work integrates the Taylor theorem and the method of fundamental solutions to develop a numerical tool for estimating the added mass coefficient tensor for a solid object of any convex shape moving in potential flow. In potential flow theory, the Taylor theorem calculates the added mass coefficient tensor for a Rankine body with algebraic manipulations of the properties of the internal singularities employed to generate the corresponding flow. To apply this theorem for objects in other shapes, the singularity strength and locations are required information which is facilitated numerically in this work by the method of fundamental solutions (MFS). The developed scheme is tested on a circle, an ellipse, a square, and a rhombus and the numerical results are in good agreement with the corresponding analytical values. A final example of a Cassini oval is also considered to show the potential applications on bio-engineering problems.
Theoretical Analysis of Cylindrical Microparticle Photophoresis in a Perpendicular Optical Field with Thermal Stress Slip Model
Authors: Tzeng P.-Y. , Liu C.-H. , Li W.-K. , Soong C.-Y.
Published: March 2012

The present study is concerned with a theoretical analysis of the photophoresis of a microsized long cylinder in a perpendicular optical field. Different from previous studies of photophoresis, thermal stress slip usually neglected is taken into account in the analysis. The gaseous fluid relative to the microparticle in photophoretic motion falls into slip-flow regime. Asymmetric distribution of the absorbed heat energy within the particle becomes the driving force for photophoretic motion of the cylinder-shaped particle. By evaluating heat source function distributions at various conditions, the study focuses on the effects of particle size and optical properties on the energy distribution and the resultant influences on the photophoresis. The photophoretic mobility is developed by the slip flow model with consideration of thermal stress slip. The results reveal that the photophoretic mobility decreases with the increase of particle thermal conductivity (k*) and increases with Knudsen number (Kn). The thermal stress slip effect on photophoretic velocity is more noticeable at highKn, but disappears at the continuum limit. A long cylinder-shaped particle has higher photophoretic velocity than a spherical particle at lowk*, while the situation reverses at highk*. With thermal stress slip considered, the critical condition for crossing of the photophoretic velocity curves of cylindrical and spherical particles is mildly influenced byKn.
Modified Kastner Formula for Cylindrical Cavity Contraction in Mohr-Coulomb Medium for Circular Tunnel in Isotropic Medium
Authors: Cheng Y. M.
Published: March 2012

The Kastner formula for cavity contraction is one of the commonly used formulae for the cavity contraction problem in tunnel excavation, and it is based on the assumption of small displacement around the cavity with no volume change in the plastic zone. In this paper, the errors arising from these assumptions are discussed, and the volume change of the plastic zone is considered. It can be seen that this assumption is reasonable for normal situations, but for rock with weak shear strength, the Kastner formula should be used with care, especially in situations where there will be relatively large volume changes in the plastic zone.
Fourier Expansion to Elastic Vector Wave Functions and Applications of Wave Bases to Scattering in Half-Space
Authors: Shih P.-J. , Teng T.-J. , Yeh C.-S.
Published: March 2012

This paper proposes a complete basis set for analyzing elastic wave scattering in half-space. The half-space is an isotropic, linear, and homogeneous medium except for a finite inhomogeneity. The wave bases are obtained by combining buried source functions and their reflected counter-waves generated from the infinite-plane boundary. The source functions are the vector wave functions of infinite-space. Based on the source functions expressed in the Fourier expansion form, the reflected counter-waves are easily obtained by solving the infinite-plane boundary conditions. Few representations adopt Wely's integration, but the Fourier expansion is developed from it and applied to decouple the angular-differential terms of the vector wave functions. In addition to the scattering of the finite inhomogeneity, the transition matrix method is extended to express the surface boundary conditions. For the numerical application in this paper, the P- and the SV- waves are assumed as the incoming fields. As an example, this paper computes stress concentrations around a cavity. The steepest-descent path method yielding the optimum integral paths is used to ensure the numerical convergence of the wave bases in the Fourier expansion. The resultant patterns from these approaches are compared with those obtained from numerical simulations.
Aerodynamic Investigations of Low-Aspect-Ratio Thin Plate Wings at Low Reynolds Numbers
Authors: Liu Y.-C. , Hsiao F.-B.
Published: March 2012

To realize the relationship between flow structures of wingtip vortices and post stall characteristics of low aspect-ratio wings, this paper experimentally studies the aerodynamic characteristics and the corresponding flow structures of the rectangular thin-plate wings at Reynolds numbers between 104 and 105. The aerodynamic properties to be studied include lift, drag, slopes at linear and nonlinear range of the lift curves and lift-to-drag ratios of the tested wings with the aspect ratio varying from 1.0 to 3.0. The flow structures regarding the leading-edge separation vortices and wingtip vortices at upper surface and near-wake regions of the wings are also investigated by smoke-wire visualization. Results indicate that the high stall angle of attack and vortex lift are clearly manifested to induce the nonlinear increase in the lift curves as the aspect ratio reaches less than 1.6. This phenomenon is specifically observed to augment the aerodynamic properties with the decrease of the aspect ratio. Additionally, the corresponding flow visualization also indicates that the wingtip vortices and the areas of highly affected regions are duly increased with the increase of the angle of attack up to 40°, which makes certain that the extra increase of the nonlinear lift results from these vortices. This result can be practically applied to the planform design for unmanned aerial vehicles.
ON PAIRS OF LINEAR EQUATIONS IN FOUR PRIME VARIABLES AND POWERS OF TWO
Authors: KONG YAFANG
Published: March 2012

In this paper, we consider the simultaneous representation of pairs of positive integers. We show that every pair of large positive even integers can be represented in the form of a pair of linear equations in four prime variables and k powers of two. Here, k=63 in general and k=31 under the generalised Riemann hypothesis.
Global Migration and Political Regime Type: A Democratic Disadvantage
Authors: Breunig Christian , Cao Xun , Luedtke Adam
Published: March 2012

An indicator of globalization is the growing number of humans crossing national borders. In contrast to explanations for flows of goods and capital, migration research has concentrated on unilateral movements to rich democracies. This focus ignores the bilateral determinants of migration and stymies empirical and theoretical inquiry. The theoretical insights proposed here show how the regime type of both sending and receiving countries influences human migration. Specifically, democratic regimes accommodate fewer immigrants than autocracies and democracies enable emigration while autocracies prevent exit. The mechanisms for this divergence are a function of both micro-level motivations of migrants and institutional constraints on political leaders. Global bilateral migration data and a statistical method that captures the higher-order dependencies in network data are employed in this article.
Partitions of Memory: Wounds and Witnessing in Cyprus
Authors: Bryant Rebecca
Published: March 2012

The image has become an iconic one: five young men in dirty uniforms kneel in the middle of a dusty plain with their hands behind their heads. They squint in the blinding midday sun, their faces expressing anxiety and a measure of fear. A Turkish soldier leans to talk to one of them, appearing calm, even friendly. To one side another Turkish soldier whose face we do not see stands guard. This photograph has become one of the most famous images to come out of the Cyprus conflict. The men's kneeling posture, the fright in their eyes, and the apparent calm of the soldiers all evoke a vulnerability to violence. And like the bloody photo of a woman and her children murdered in their Nicosia home that was used for decades by the Turkish Cypriot administration, or like certain photographs of distraught women crying for losses that we can only imagine, the image of these five young men has been reprinted in pamphlets and brochures, newspapers and books, in ways that take for granted its power to evoke their uncertain fate.
Apuleius
Authors: Ferguson John
Published: March 2012

To one nurtured on the pure and sustaining milk of Cicero and the Augustans, with an occasional dash of Tacitus and Juvenal for medicinal purposes, the writings of Apuleius come with something of the force of a knock-me-down. The very words are unfamiliar. Barrio is onomatopoeic enough to be guessed, but what does vispellio mean to anyone outside the legal profession? What of cambio? His is a strange language, highly artificial, with its borrowings from the Greek—myoparo, schedium, and naulum, which Juvenal took before him, for instance; with its echoes of Plautus—tuburdnor, scitulus, atticisso, capero, ientaculum, agaso, lurco, pollinctor, cincinnus, and examussim are all Plautine; with its diminutives, always a sign of artifice, as it was the sign of the Graecis-santes of Cicero's day—mellitula, tenella, centunculus, sdtulus spring to the mind; with comparatively unfamiliar literary words—tesca and blatero are both Horatian, but are very rare; and with his own occasional extensions of usage, as when he describes his horse as vector meus, or speaks of a kiss being given pressule, or seemingly coins subterlabere for ‘to slight’. But with this mannered artificiality goes the easy conversational idiom of the professional popular writer, evinced by his repeated use of commodum in the Metamorphoses to carry on the flow of ideas. Fuscis avibus or sinistro pede for ‘without luck’ are as artificial as the rest, but minimo minus for ‘almost’, or dicam an with the indicative for immo vero are surely conversational.
The Lesson Which India Is Today Teaching the World: Nationalism and Internationalism inThe Crisis, 1910–1934
Authors: FAREBROTHER RACHEL
Published: March 2012

This article aims to test the limits of current assessments of the New Negro renaissance, which tend to emphasize either its investment in cultural nationalism or its Pan-African focus, by exploring the international contours ofThe Crisisunder Du Bois’s editorship. Recent analysis ofThe Crisishas paid considerable attention to the productive juxtaposition of what Anne Carroll has termed “protest and affirmation,” whereby Du Bois positioned reports on racial violence next to accounts of African American achievements in order to prompt acknowledgement of the realities of racism. But such criticism has focussed almost exclusively upon Du Bois’s treatment of American issues, overlooking his sustained interest in international cultural and political concerns. Focussing on the editorial framing of Indian nationalism, this article contends that the common distinctions drawn between internationalism and nationalism are too simplistic to accommodateThe Crisis's formulation of cultural nationalism by way of internationalism. Indeed, scrutiny of the magazine's formal texture, which stages dynamic interplay between poetry, short fiction, investigative journalism, photography, readers' letters and political cartoons, reveals tensions that animate Du Bois's project, not least his dependence upon colonialist ways of seeing and a narrative of racial unity across the African diaspora that serves to elide cultural and historical specificity.
Sole larval distribution (Solea solea) in the eastern English Channel and Southern Bight of the North Sea
Authors: Grioche A. , Koubbi P. , Harlay X. , Sautour B.
Published: March 2012

The distribution of sole (Solea solea) eggs and larvae were described from two cruises conducted in April and May 1995 along the French coast of the eastern English Channel and the Belgian coast of the Southern Bight of the North Sea. Sole migration was investigated using larval stages and univariate spatial analysis as geostatistics (variograms). Important environmental parameters were selected by comparison with larval distribution. Path analysis was used to remove spatial correlation and to define links between abundance and environmental variables.  Sole larvae were found to be coastal throughout their development. Strong links between larval distribution and environmental parameters were identified, particularly for the younger stages which were found in higher abundance in areas of high chlorophyll-a concentration. The association was not direct, suggesting that the larval spatial distribution was influenced by an undetermined, intermediate variable, such as larval prey. Sole larvae are retained in the coastal area throughout ontogeny despite the strong hydrodynamics which characterize the region. Larval distribution resulted from behavioural mechanisms as well as environmental influences.
Cryptostatin, a chagasin-family cysteine protease inhibitor ofCryptosporidium parvum
Authors: KANG J.-M. , JU H.-L. , YU J.-R. , SOHN W.-M. , NA B.-K.
Published: March 2012

Cysteine proteases of pathogenic protozoan parasites play pivotal roles in the life cycle of parasites, but strict regulation of their activities is also essential for maintenance of parasite physiology and interaction with hosts. In this study, we identified and characterized cryptostatin, a novel inhibitor of cysteine protease (ICP) ofCryptosporidium parvum. Cryptostatin showed low sequence identity to other chagasin-family ICPs, but 3 motifs (NPTTG, GXGG, and RPW/F motifs), which are evolutionarily conserved in chagasin-family ICPs, were found in the sequence. The overall structure of cryptostatin consisted of 8β-strands that progressed in parallel and closely resembled the immunoglobulin fold. Recombinant cryptostatin inhibited various cysteine proteases, including papain, human cathepsin B, human cathepsin L, and cryptopain-1, withKi's in the picomolar range. Cryptostatin was active over a wide pH range and was highly stable under physiological conditions. The protein was thermostable and retained its inhibitory activity even after incubation at 95°C. Cryptostatin formed tight complexes with cysteine proteases, so the complexes remained intact in the presence of sodium dodecyl sulfate andβ-mercaptoethanol, but they were disassembled by boiling. An immunogold electron microscopy analysis demonstrated diffused localization of cryptostatin within oocystes and meronts, but not within trophozoites, which suggests a possible role for cryptostatin in host cell invasion byC. parvum.
Intensity of parasitic mite infection decreases with hibernation duration of the host snail
Authors: HAEUSSLER E. M. , PIZÁ J. , SCHMERA D. , BAUR B.
Published: March 2012

Temperature can be a limiting factor on parasite development.Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection byR. limacumin populations of the land snailArianta arbustorumis highly variable (0–78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4–7 months. Winter survival of host snails was negatively affected byR. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus,R. limacumsurvives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence ofR. limacum.
The relationship between executive functions and fluid intelligence in Parkinson's disease
Authors: Roca M. , Manes F. , Chade A. , Gleichgerrcht E. , Gershanik O. , Arévalo G. G. , Torralva T. , Duncan J.
Published: March 2012

Background

We recently demonstrated that decline in fluid intelligence is a substantial contributor to frontal deficits. For some classical ‘executive’ tasks, such as the Wisconsin Card Sorting Test (WCST) and Verbal Fluency, frontal deficits were entirely explained by fluid intelligence. However, on a second set of frontal tasks, deficits remained even after statistically controlling for this factor. These tasks included tests of theory of mind and multitasking. As frontal dysfunction is the most frequent cognitive deficit observed in early Parkinson's disease (PD), the present study aimed to determine the role of fluid intelligence in such deficits.

Method

We assessed patients with PD (n=32) and control subjects (n=22) with the aforementioned frontal tests and with a test of fluid intelligence. Group performance was compared and fluid intelligence was introduced as a covariate to determine its role in frontal deficits shown by PD patients.

Results

In line with our previous results, scores on the WCST and Verbal Fluency were closely linked to fluid intelligence. Significant patient–control differences were eliminated or at least substantially reduced once fluid intelligence was introduced as a covariate. However, for tasks of theory of mind and multitasking, deficits remained even after fluid intelligence was statistically controlled.

Conclusions

The present results suggest that clinical assessment of neuropsychological deficits in PD should include tests of fluid intelligence, together with one or more specific tasks that allow for the assessment of residual frontal deficits associated with theory of mind and multitasking.
Touring History: Tórtola Valencia Between Europe and the Americas
Authors: Clayton Michelle
Published: March 2012

In 1907, the Nicaraguan poet Rubén Darío published the collection El canto errante [The Wandering Song], containing a poem entitled “La bailarina de los pies desnudos” [“The Barefoot Dancer”]. The title leads the reader to anticipate an aesthetic of lightness and simplicity, yet the poem is weighted down by its many cultural references: at least one per line, and barely harmonizing amongst themselves. Its space is heavily perfumed, thickly ornamented, animated by the movements of a dancer who invokes different cultural references and plastic forms with each extended limb, each trembling body part. At first sight sinuously seductive, this central figure unravels into a welter of fragments and contradictions: both animal and divine, eroticized and chaste, a lunar deity (Selene) and a literary character (Anactoria), a “constellation of examples and of objects” (constelada de casos y de cosas) whose body, as the line suggests, barely contains its referential chaos.