bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive and Model-Based Control Theory Applied to Convectively Unstable Flows
Authors: Fabbiane Nicolò , Semeraro Onofrio , Bagheri Shervin , Henningson Dan S.
Published: April 2014

Research on active control for the delay of laminar–turbulent transition in boundary layers has made a significant progress in the last two decades, but the employed strategies have been many and dispersed. Using one framework, we review model-based techniques, such as linear-quadratic regulators, and model-free adaptive methods, such as least-mean square filters. The former are supported by an elegant and powerful theoretical basis, whereas the latter may provide a more practical approach in the presence of complex disturbance environments that are difficult to model. We compare the methods with a particular focus on efficiency, practicability and robustness to uncertainties. Each step is exemplified on the one-dimensional linearized Kuramoto–Sivashinsky equation, which shows many similarities with the initial linear stages of the transition process of the flow over a flat plate. Also, the source code for the examples is provided.
Nuclear Envelope Lamin-A Couples Actin Dynamics with Immunological Synapse Architecture and T Cell Activation
Authors: González-Granado José M. , Silvestre-Roig Carlos , Rocha-Perugini Vera , Trigueros-Motos Laia , Cibrián Danay , Morlino Giulia , Blanco-Berrocal Marta , Osorio Fernando G. , Freije José M. P. , López-Otín Carlos , Sánchez-Madrid Francisco , Andrés Vicente
Published: April 2014

Communication between the nuclear lamina protein lamin-A and the actin cytoskeleton is required for optimal T cell responses.
Science Signaling
Podcast: 22 April 2014
Authors: González-Granado José María , Sánchez-Madrid Francisco , Andrés Vicente , VanHook Annalisa M.
Published: April 2014

Lamin-A links the nuclear skeleton with the cytoskeleton to modulate signaling through immunological synapses.
miRly Interfering with Junctions
Authors: VanHook Annalisa M.
Published: April 2014

An exosome-delivered and cancer cell–derived microRNA increases vascular permeability and promotes metastasis.
Inhibited from Across the Way
Authors: Gough Nancy R.
Published: April 2014

Cis presentation of neuropilin 1 with the vascular growth factor receptor promotes angiogenesis, whereas trans presentation inhibits angiogenesis.
Universal Immune Function
Authors: Hines Pamela J.
Published: April 2014

A heterodimer stands at the ready; a homodimer responds with action.
In Vitro
Amphotericin B Susceptibility of Malassezia pachydermatis Determined by the CLSI Broth Microdilution Method and Etest Using Lipid-Enriched Media
Authors: Álvarez-Pérez Sergio , Blanco José L. , Peláez Teresa , Cutuli Maite , García Marta E.
Published: April 2014

We determined the
in vitro
amphotericin B susceptibility of 60
Malassezia pachydermatis
isolates by the CLSI broth microdilution method and the Etest using lipid-enriched media. All isolates were susceptible at MICs of ≤1 μg/ml, confirming the high activity of amphotericin B against this yeast species. Overall, the essential agreement between the tested methods was high (80% and 96.7% after 48 h and 72 h, respectively), and all discrepancies were regarded as nonsubstantial.
Lack of Antimicrobial Bactericidal Activity in Mycobacterium abscessus
Authors: Maurer Florian P. , Bruderer Vera L. , Ritter Claudia , Castelberg Claudio , Bloemberg Guido V. , Böttger Erik C.
Published: April 2014

Antibiotic therapy of infections caused by the emerging pathogen
Mycobacterium abscessus
is challenging due to the organism's natural resistance toward most clinically available antimicrobials. We investigated the bactericidal activity of antibiotics commonly administered in
M. abscessus
infections in order to better understand the poor therapeutic outcome. Time-kill curves were generated for clinical
M. abscessus
isolates,
Mycobacterium smegmatis
, and
Escherichia coli
by using antibiotics commonly categorized as bactericidal (amikacin and moxifloxacin) or bacteriostatic (tigecycline and linezolid). In addition, the impact of aminoglycoside-modifying enzymes on the mode of action of substrate and nonsubstrate aminoglycosides was studied by using
M. smegmatis
as a model organism. While amikacin and moxifloxacin were bactericidal against
E. coli
, none of the tested compounds showed bactericidal activity against
M. abscessus
. Further mechanistic investigations of the mode of action of aminoglycosides in
M. smegmatis
revealed that the bactericidal activity of tobramycin and gentamicin was restored by disruption of the chromosomal
aac(2
′) gene in the mycobacterial genome. The lack of bactericidal antibiotics in currently recommended treatment regimens provides a reasonable explanation for the poor therapeutic outcome in
M. abscessus
infection. Our findings suggest that chromosomally encoded drug-modifying enzymes play an important role in the lack of aminoglycoside bactericidal activity against rapidly growing mycobacteria.
Cohort Study of the Impact of Time to Antibiotic Administration on Mortality in Patients with Febrile Neutropenia
Authors: Rosa Regis G. , Goldani Luciano Z.
Published: April 2014

The time to antibiotic administration (TTA) has been proposed as a quality-of-care measure in febrile neutropenia (FN); however, few data regarding the impact of the TTA on the mortality of adult cancer patients with FN are available. The objective of this study was to determine whether the TTA is a predictor of mortality in adult cancer patients with FN. A prospective cohort study of all consecutive cases of FN, evaluated from October 2009 to August 2011, at a single tertiary referral hospital in southern Brazil was performed. The TTA was assessed as a predictive factor for mortality within 28 days of FN onset using the Cox proportional hazards model. Kaplan-Meier curves were used for an assessment of the mortality rates according to different TTAs; the log-rank test was used for between-group comparisons. In total, 307 cases of FN (169 subjects) were evaluated. During the study period, there were 29 deaths. In a Cox regression analysis, the TTA was independently associated with mortality within 28 days (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.10 to 1.26); each increase of 1 h in the TTA raised the risk of mortality within 28 days by 18%. Patients with FN episodes with a TTA of ≤30 min had lower 28-day mortality rates than those with a TTA of between 31 min and 60 min (3.0% versus 18.1%; log-rank
P
= 0.0002). Early antibiotic administration was associated with higher survival rates in the context of FN. Efforts should be made to ensure that FN patients receive effective antibiotic therapy as soon as possible. A target of 30 min to the TTA should be adopted for cancer patients with FN.
Amikacin-Fosfomycin at a Five-to-Two Ratio: Characterization of Mutation Rates in Microbial Strains Causing Ventilator-Associated Pneumonia and Interactions with Commonly Used Antibiotics
Authors: Montgomery A. Bruce , Rhomberg Paul R. , Abuan Tammy , Walters Kathie-Anne , Flamm Robert K.
Published: April 2014

The amikacin-fosfomycin inhalation system (AFIS), a combination of antibiotics administered with an in-line nebulizer delivery system, is being developed for adjunctive treatment of ventilator-associated pneumonia (VAP). The
in vitro
characterization of amikacin-fosfomycin (at a 5:2 ratio) described here included determining resistance selection rates for pathogens that are representative of those commonly associated with VAP (including multidrug-resistant strains) and evaluating interactions with antibiotics commonly used intravenously to treat VAP. Spontaneous resistance to amikacin-fosfomycin (5:2) was not observed for most strains tested (
n
, 10/14). Four strains had spontaneously resistant colonies (frequencies, 4.25 × 10
−8
to 3.47 × 10
−10
), for which amikacin-fosfomycin (5:2) MICs were 2- to 8-fold higher than those for the original strains. After 7 days of serial passage, resistance (>4-fold increase over the baseline MIC) occurred in fewer strains (
n
, 4/14) passaged in the presence of amikacin-fosfomycin (5:2) than with either amikacin (
n
, 7/14) or fosfomycin (
n
, 12/14) alone. Interactions between amikacin-fosfomycin (5:2) and 10 comparator antibiotics in checkerboard testing against 30 different Gram-positive or Gram-negative bacterial strains were synergistic (fractional inhibitory concentration [FIC] index, ≤0.5) for 6.7% (
n
, 10/150) of combinations tested. No antagonism was observed. Synergy was confirmed by time-kill methodology for amikacin-fosfomycin (5:2) plus cefepime (against
Escherichia coli
), aztreonam (against
Pseudomonas aeruginosa
), daptomycin (against
Enterococcus faecalis
), and azithromycin (against
Staphylococcus aureus
). Amikacin-fosfomycin (5:2) was bactericidal at 4-fold the MIC for 7 strains tested. The reduced incidence of development of resistance to amikacin-fosfomycin (5:2) compared with that for amikacin or fosfomycin alone, and the lack of negative interactions with commonly used intravenous antibiotics, further supports the development of AFIS for the treatment of VAP.
Potentiation Effects of Amikacin and Fosfomycin against Selected Amikacin-Nonsusceptible Gram-Negative Respiratory Tract Pathogens
Authors: Montgomery A. Bruce , Rhomberg Paul R. , Abuan Tammy , Walters Kathie-Anne , Flamm Robert K.
Published: April 2014

The amikacin-fosfomycin inhalation system (AFIS) is a combination of 2 antibiotics and an in-line nebulizer delivery system that is being developed for adjunctive treatment of pneumonia caused by Gram-negative organisms in patients on mechanical ventilation. AFIS consists of a combination of amikacin and fosfomycin solutions at a 5:2 ratio (amikacin, 3 ml at 100 mg/ml; fosfomycin, 3 ml at 40 mg/ml) and the PARI Investigational eFlow Inline System. In this antibiotic potentiation study, the antimicrobial activities of amikacin and fosfomycin, alone and in a 5:2 combination, were assessed against 62 Gram-negative pathogens from a worldwide antimicrobial surveillance collection (SENTRY). The amikacin MICs for 62 isolates of
Acinetobacter baumannii
,
Pseudomonas aeruginosa
, and
Klebsiella pneumoniae
were ≥32 μg/ml (intermediate or resistant according to the Clinical and Laboratory Standards Institute [CLSI]; resistant according to the European Committee on Antimicrobial Susceptibility Testing [EUCAST]). Each isolate was tested against amikacin (0.25 to 1,024 μg/ml), fosfomycin (0.1 to 409.6 μg/ml), and amikacin-fosfomycin (at a 5:2 ratio) using CLSI reference agar dilution methods. The median MIC values for amikacin and fosfomycin against the 62 isolates each decreased 2-fold with the amikacin-fosfomycin (5:2) combination from that with either antibiotic alone. Interactions between amikacin and fosfomycin differed by isolate and ranged from no detectable interaction to high potentiation. The amikacin-fosfomycin (5:2) combination reduced the amikacin concentration required to inhibit all 62 isolates from >1,024 to ≤256 μg/ml and reduced the required fosfomycin concentration from 204.8 to 102.4 μg/ml. These results support continued development of the amikacin-fosfomycin combination for aerosolized administration, where high drug levels can be achieved.
VCAM-1/α4β1 Integrin Interaction Is Crucial for Prompt Recruitment of Immune T Cells into the Brain during the Early Stage of Reactivation of Chronic Infection with Toxoplasma gondii To Prevent Toxoplasmic Encephalitis
Authors: Sa Qila , Ochiai Eri , Sengoku Tomoko , Wilson Melinda E. , Brogli Morgan , Crutcher Stephen , Michie Sara A. , Xu Baohui , Payne Laura , Wang Xisheng , Suzuki Yasuhiro
Published: April 2014

Reactivation of chronic infection withToxoplasma gondiican cause life-threatening toxoplasmic encephalitis in immunocompromised individuals. We examined the role of VCAM-1/α4β1 integrin interaction in T cell recruitment to prevent reactivation of the infection in the brain. SCID mice were infected and treated with sulfadiazine to establish a chronic infection. VCAM-1 and ICAM-1 were the endothelial adhesion molecules detected on cerebral vessels of the infected SCID and wild-type animals. Immune T cells from infected wild-type mice were treated with anti-α4 integrin or control antibodies and transferred into infected SCID or nude mice, and the animals received the same antibody every other day. Three days later, sulfadiazine was discontinued to initiate reactivation of infection. Expression of mRNAs for CD3δ, CD4, CD8β, gamma interferon (IFN-γ), and inducible nitric oxide synthase (NOS2) (an effector molecule to inhibitT. gondiigrowth) and the numbers of CD4+and CD8+T cells in the brain were significantly less in mice treated with anti-α4 integrin antibody than in those treated with control antibody at 3 days after sulfadiazine discontinuation. At 6 days after sulfadiazine discontinuation, cerebral tachyzoite-specific SAG1 mRNA levels and numbers of inflammatory foci associated with tachyzoites were markedly greater in anti-α4 integrin antibody-treated than in control antibody-treated animals, even though IFN-γ and NOS2 mRNA levels were higher in the former than in the latter. These results indicate that VCAM-1/α4β1 integrin interaction is crucial for prompt recruitment of immune T cells and induction of IFN-γ-mediated protective immune responses during the early stage of reactivation of chronicT. gondiiinfection to control tachyzoite growth.
Probabilistic observational method for estimating wall displacements in excavations
Authors: Wu Shih-Hsuan , Ching Jianye , Ou Chang-Yu
Published: April 2014

In this study, a novel method for updating the probability distribution of the maximum wall displacement at the ith excavation stage ([Formula: see text]) based on the measurements at earlier stages is proposed. The main novelty of the proposed method is in the updating procedure, which incorporates the correlation among the estimation errors at various stages. This “stage correlation” is evident from a database of wall displacement data from 22 case histories. By incorporating the stage correlation, it is shown that the uncertainty in [Formula: see text] can be effectively reduced through a Bayesian analysis. Furthermore, the calculation steps for such updating can be easily implemented by practical engineers because these calculation steps involve only algebraic computations and chart checking. Sophisticated analyses, such as solving an optimization problem (required by the maximum likelihood method) and probabilistic analyses are not necessary because all of the Bayesian analysis results are summarized in the charts.
Transformations and correlations among some clay parameters — the global database
Authors: Ching Jianye , Phoon Kok-Kwang
Published: April 2014

This study compiles a large database of 10 clay parameters (labeled as CLAY/10/7490) from 251 studies, covering clay data from 30 regions or countries worldwide. Hence, the range of data covered by this “global” database is broader than that underlying the calibration of existing transformation models in the literature. These transformation models relate test measurements (e.g., cone tip resistance) to appropriate design parameters (e.g., undrained shear strength). The correlation behaviours exhibited by the database among the 10 clay parameters are consistent with those exhibited by existing transformation models in the literature. The biases and transformation uncertainties of these transformation models with respect to the global database are calibrated. It is found that more recent transformation models are less biased and that the transformation uncertainties are typically fairly large. Such large transformation uncertainties are further reduced by incorporating secondary input parameters, such as plasticity index or sensitivity. In a companion paper written by the same authors, a 10-dimensional multivariate probability distribution coupling these clay parameters is constructed from CLAY/10/7490 and a useful application involving updating the entire bivariate probability distribution of two design parameters from three separate measurements is presented.
A stratification on the moduli spaces of symplectic and orthogonal bundles over a curve
Authors: Choe Insong , Hitching G. H.
Published: April 2014

A symplectic or orthogonal bundle V of rank 2n over a curve has an invariant t(V) which measures the maximal degree of its isotropic subbundles of rank n. This invariant t defines stratifications on moduli spaces of symplectic and orthogonal bundles. We study this stratification by relating it to another one given by secant varieties in certain extension spaces. We give a sharp upper bound on t(V), which generalizes the classical Nagata bound for ruled surfaces and the Hirschowitz bound for vector bundles, and study the structure of the stratifications on the moduli spaces. In particular, we compute the dimension of each stratum. We give a geometric interpretation of the number of maximal Lagrangian subbundles of a general symplectic bundle, when this is finite. We also observe some interesting features of orthogonal bundles which do not arise for symplectic bundles, essentially due to the richer topological structure of the moduli space in the orthogonal case.
Supersymmetric invariant theories
Authors: Esipova S. R. , Lavrov P. M. , Radchenko O. V.
Published: April 2014

We study field models for which a quantum action (i.e. the action appearing in the generating functional of Green functions) is invariant under supersymmetric transformations. We derive the Ward identity which is a direct consequence of this invariance. We consider a change of variables in functional integral connected with supersymmetric transformations when its parameter is replaced by a nilpotent functional of fields. Exact form of the corresponding Jacobian is found. We find restrictions on generators of supersymmetric transformations when a consistent quantum description of given field theories exists.
On the bounds of CKM matrix element Vcb in a potential model
Authors: Choudhury D. K. , Pathak Krishna Kingkar
Published: April 2014

Considering the allowed range of slope ρ2 and curvature C of Isgur–Wise function for B meson, we obtain an allowed range of strong coupling constant αs as well as the QCD scale parameter Λ in a specific prescription. The allowed range of Λ is then used to obtain the theoretical bounds on Vcb in a potential model. The recent available data of Vcb are found to lie within this computed range 0.0375 ≤|Vcb|≤0.0410.
Structural and electrical properties of zirconium doped yttrium oxide nanostructures
Authors: Bahari Ali , Ebrahimzadeh Masoud , Gholipur Reza
Published: April 2014

A synthetic process for the formation of Zr x Y 1-x O y nanostructures is demonstrated by the reaction of yttrium nitrate hexahydrate with zirconium propoxide. The reactions are carried out at temperature 60°C and pressure 0.1 MPa. The energy dispersive X-ray (EDX) spectroscopy measurements confirm formation of Zr x Y 1-x O y nanostructures and the presence of carbonate and hydroxide species which are removed after high temperature anneals. It was found that the oxygen pressure during synthesis plays a determinant role on the structural properties of the nanostructure. This effect is further studied by atomic force microscopy (AFM) measurements and scanning electron microscope (SEM), which showed the formation of an isotopically organized structure. X-ray diffraction (XRD) measurement reveals that these changes in the nanostructural efficiency are associated with structural and compositional changes among the substrate. The dielectric constant as measured by the capacitance–voltage (C–V) technique is estimated to be around 39.05. C–V measurements taken at 1 MHz show the maximum capacitance for the Zr 0.05 Y 0.95 O y film. The leakage current densities were below 10-5 A/cm2 for the Zr 0.05 Y 0.95 O y film.
Density functional theory calculations for the investigation of (Ag, N) codoping effect on the electronic and optical properties of anataseTiO2
Authors: Khan Matiullah , Cao Wenbin , Li Jing , Zaman Muhammad Iqbal , Manan Abdul
Published: April 2014

Efficient absorption of light in visible range and enhance separation of photoexcited electron-hole pairs (EHPs) are crucial for improving the photoactivity of metal nonmetal codoped TiO2. By using density functional theory (DFT) calculations, an effective metal ( Ag ) and nonmetal ( N ) codoping approach is described to modify the photoelectrochemical properties of titanium dioxide ( TiO2). Nitrogen (N) doping introduces isolated N -2p states above the valence band maximum (VBM) which acts as an electron trap to promote EHP recombination. For Ag -doped TiO2, Ag -4d states are introduced above the VBM which leads to the band gap narrowing. Silver (Ag) and nitrogen codoped TiO2possess stable configuration, narrowed band gap and best visible light absorption. Defect pair binding energy calculation shows that individual dopants, located at a distance of 8.951 Å bind each other, which indicates that the defect pair is stable compared to the isolated impurities in the host lattice. Ag and N codoped TiO2shows better visible light absorption as compared to other doped models due to the reduced band gap. N doping reduces the band gap of TiO2while Ag doping enhances the EHPs separation, so their combined presence in a sample would improve the photocatalytic activity due to their synergistic codoping effect. Our calculations provide reasonable explanation for the experimental findings.
CLUSTERING OF 3D LINE SEGMENTS USING CENTROID NEURAL NETWORK FOR BUILDING DETECTION
Authors: PARK DONG-CHUL , WOO DONG-MIN , KIM CHANG-SUN , MIN SOO-YOUNG
Published: April 2014

An efficient method for rectangular boundary extraction from aerial image data is proposed in this paper. A centroid neural network (CNN) with a metric utilizing line segments is adopted to group low-level line segments for detecting rectangular objects. The proposed method extracts rectangular boundaries for building rooftops from 3D edge images with various types of noises arising from the stereo matching process. In order to overcome the noises in 3D edge images including line segments of shadows, a clustering method utilizes the constraint where the heights of building rooftops are similar and the clustering process is performed with candidate 3D line segments with similar heights. Experiments are performed with a set of high-resolution satellite image data. The results show that the proposed method can remove noisy segments including shadow lines efficiently and thus find more accurate rectangular boundaries and building information.
A dynamical mass and confinement in nucleon model
Authors: Jia Duojie , Wan Ruibin , Yu Lianchun
Published: April 2014

A possible dynamical softening of the Chiral bag is studied in connection with the chiral quark model and the Nambu–Jona–Lasinio (NJL) model. It is demonstrated that the bag functions constructed by the pion degrees is able to confine quark through generation of the rising effective mass of valence quark due to the pion dressing and break chiral symmetry dynamically. The tendency of the bag functions toward the MIT bag is illustrated in the large-n limit for a solitonic configuration of the chiral field Un(r) for which U1(r) is the Skyrmion profile. The mass running with the length scale agrees with that of the NJL Model for n ≥ 2.
A DIFFUSIVE-TRANSPORT-BASED APPROACH TO DETERMINE THE ELECTRICAL CONDUCTANCE OF AN IMPERFECT MULTIWALLED CARBON NANOTUBE
Authors: GRADO-CAFFARO MARIA ANGELES , GRADO-CAFFARO MARTIN
Published: April 2014

In this paper, we propose a diffusive-transport-based analytical formulation to calculate the linear electrical conductance through a multiwalled carbon nanotube with defects. In fact, on the one hand, by considerations on diffusive transport and, on the other hand, using the Drude model, we find out that the conductance (at Fermi energy) of an imperfect multiwalled carbon nanotube is approximately equal to the fundamental conductance quantum multiplied by the number of layers (or shells) of the tube. Our result agrees with experimental data.
DFT STUDY OF HYDROGEN STORAGE ON Li- AND Na-DOPED C59B HETEROFULLERENE
Authors: ZAHEDI EHSAN , MOZAFFARI MAJID
Published: April 2014

Effect of light alkali metal ( Li and Na ) decorated on the C 59 B heterofullerene for hydrogen storage is considered using DFT-MPW1PW91 method. Results show that Li and Na atoms strongly prefer to adsorb on top of five-member and six-member ring where a carbon atom is replaced by a boron atom. Significant charge transfer from the alkali metal to the C 59 B compensates for the electron deficiency of C 59 B and makes the latter aromatic in nature. Corrected binding energies of hydrogen molecule on the alkali-doped C 59 B using counterpoise method, structural properties and NBO analysis indicate that first hydrogen molecule is adsorbed physically and does not support minimal conditions of DOE requirement. Finally, positive values of binding energies for the adsorption of a second hydrogen molecule show that alkali doped C 59 B are capable of storing a maximum of one hydrogen molecule.
DESIGNING BUSINESS MODEL CHANGE
Authors: CAVALCANTE SÉRGIO ANDRÉ
Published: April 2014

The aim of this paper is to base organisational change on the firm's business model, an approach that research has only recently start to address. This study adopts a process-based perspective on business models and insights from a variety of theories as the basis for the development of ideas on the design of business model change. This paper offers a new, process-based strategic analytical artefact for the design of business model change, consisting of three main phases. Designing business model change as suggested in this paper allows ex ante analysis of alternative scenarios of change in a structured and comprehensive way. Such a tool is useful for obtaining an overall view of the working logic of the firm and to facilitate innovation through change. The main contribution of this paper is to transform management theories into an instrument that can be helpful for companies to develop their capacity to change in a more focused and structured way.
MOLECULAR CHARACTERIZATION OF A NOVEL RAT PARVOVIRUS IN TAIWAN
Authors: Liao Yi-Chun , Wang Ming-Hseng , Wan Cho-Hua
Published: April 2014

Rodent parvoviruses are among the most prevalent infectious agents in laboratory rodents and have been shown to interfere with in vivo and in vitro research. A newly recognized rat parvovirus (RPV) that is distinct from the prototypic RPV was recently identified in naturally infected laboratory rats in Taiwan. Nucleotide and amino acid sequence comparisons showed that this newly identified variant of RPV is most closely related to rat parvovirus type 1a (RPV-1a) and type 1b (RPV-1b) and is distinctly different from type UT (RPV/UT) and other rodent parvoviruses. This variant was designated rat parvovirus type National Taiwan University 1 (RPV-NTU1). Phylogenetic and sequence analyses revealed that RPV-NTU1 contains conserved open reading frames with an overall genome organization similar to known RPV-1. RPV-NTU1 is the second RPV-1 variant whose full-length molecular characterization has been performed.
Eigenvalue distributions of beta-Wishart matrices
Authors: Edelman Alan , Koev Plamen
Published: April 2014

We derive explicit expressions for the distributions of the extreme eigenvalues of the beta-Wishart random matrices in terms of the hypergeometric function of a matrix argument. These results generalize the classical results for the real (β = 1), complex (β = 2), and quaternion (β = 4) Wishart matrices to any β > 0.
A Pthreads Wrapper for Fortran 2003
Authors: Awile Omar , Sbalzarini Ivo F.
Published: April 2014

With the advent of multicore processors, numerical and mathematical software relies on parallelism in order to benefit from hardware performance increases. We present the design and use of a Fortran 2003 wrapper for POSIX threads, called forthreads. Forthreads is complete in the sense that is provides native Fortran 2003 interfaces to all pthreads routines where possible. We demonstrate the use and efficiency of forthreads for SIMD parallelism and task parallelism. We present forthreads/MPI implementations that enable hybrid shared-/distributed-memory parallelism in Fortran 2003. Our benchmarks show that forthreads offers performance comparable to that of OpenMP, but better thread control and more freedom. We demonstrate the latter by presenting a multithreaded Fortran 2003 library for POSIX Internet sockets, enabling interactive numerical simulations with runtime control.
Nearly Optimal Solutions for the Chow Parameters Problem and Low-Weight Approximation of Halfspaces
Authors: De Anindya , Diakonikolas Ilias , Feldman Vitaly , Servedio Rocco A.
Published: April 2014

The
Chow parameters
of a Boolean function
f
:{−1, 1}

n

→ {−1, 1} are its
n
+1 degree-0 and degree-1 Fourier coefficients. It has been known since 1961 [Chow 1961; Tannenbaum 1961] that the (exact values of the) Chow parameters of any linear threshold function
f
uniquely specify
f
within the space of all Boolean functions, but until recently [O'Donnell and Servedio 2011] nothing was known about efficient algorithms for
reconstructing
f
(exactly or approximately) from exact or approximate values of its Chow parameters. We refer to this reconstruction problem as the
Chow Parameters Problem.

Our main result is a new algorithm for the Chow Parameters Problem which, given (sufficiently accurate approximations to) the Chow parameters of any linear threshold function
f
, runs in time Õ(
n
2
) ⋅ (1/ϵ)

O
(log
2
(1/ϵ))

and with high probability outputs a representation of an LTF
f
′ that is ϵ-close to
f
in Hamming distance. The only previous algorithm [O'Donnell and Servedio 2011] had running time poly(
n
) ⋅ 2

2

Õ(1/ϵ
2
)

.

As a byproduct of our approach, we show that for any linear threshold function
f
over {-1, 1}

n

, there is a linear threshold function
f
′ which is ϵ-close to
f
and has all weights that are integers of magnitude at most √n ⋅ (1/ϵ)

O
(log
2
(1/ϵ))

. This significantly improves the previous best result of Diakonikolas and Servedio [2009] which gave a poly(
n
) ⋅ 2

Õ(1/ϵ
2/3
)

weight bound, and is close to the known lower bound of max{√n, (1/ϵ)
Ω(log log (1/ϵ))
} [Goldberg 2006; Servedio 2007]. Our techniques also yield improved algorithms for related problems in learning theory.

In addition to being significantly stronger than previous work, our results are obtained using conceptually simpler proofs. The two main ingredients underlying our results are (1) a new structural result showing that for
f
any linear threshold function and
g
any bounded function, if the Chow parameters of
f
are close to the Chow parameters of
g
then
f
is close to
g
; (2) a new boosting-like algorithm that given approximations to the Chow parameters of a linear threshold function outputs a bounded function whose Chow parameters are close to those of
f
.
XML Schema Mappings
Authors: Amano Shun'ichi , David Claire , Libkin Leonid , Murlak Filip
Published: April 2014

Relational schema mappings have been extensively studied in connection with data integration and exchange problems, but mappings between XML schemas have not received the same amount of attention. Our goal is to develop a theory of expressive XML schema mappings. Such mappings should be able to use various forms of navigation in a document, and specify conditions on data values. We develop a language for XML schema mappings, and study both data exchange with such mappings and metadata management problems. Specifically, we concentrate on four types of problems: complexity of mappings, query answering, consistency issues, and composition.

We first analyze the complexity of mappings, that is, recognizing pairs of documents such that one can be mapped into the other, and provide a classification based on sets of features used in mappings. Next, we chart the tractability frontier for the query answering problem. We show that the problem is tractable for expressive schema mappings and simple queries, but not vice versa. Then, we move to static analysis. We study the complexity of the consistency problem, that is, deciding whether it is possible to map some document of a source schema into a document of the target schema. Finally, we look at composition of XML schema mappings. We analyze its complexity and show that it is harder to achieve closure under composition for XML than for relational mappings. Nevertheless, we find a robust class of XML schema mappings that, in addition to being closed under composition, have good complexity properties with respect to the main data management tasks. Due to its good properties, we suggest this class as the class to use in applications of XML schema mappings.
Space-Efficient Frameworks for Top-
k
String Retrieval
Authors: Hon Wing-Kai , Shah Rahul , Thankachan Sharma V. , Vitter Jeffrey Scott
Published: April 2014

The inverted index is the backbone of modern web search engines. For each word in a collection of web documents, the index records the list of documents where this word occurs. Given a set of query words, the job of a search engine is to output a ranked list of the most relevant documents containing the query. However, if the query consists of an arbitrary string—which can be a partial word, multiword phrase, or more generally any sequence of characters—then word boundaries are no longer relevant and we need a different approach. In string retrieval settings, we are given a set
D
={
d
1
,
d
2
,
d
3
, …,
d
D
} of
D
strings with
n
characters in total taken from an alphabet set Σ = [σ], and the task of the search engine, for a given query pattern
P
of length
p
, is to report the “most relevant” strings in
D
containing
P
. The query may also consist of two or more patterns. The notion of relevance can be captured by a function
score
(
P
,
d

r

), which indicates how relevant document
d

r

is to the pattern
P
. Some example score functions are the
frequency
of pattern occurrences,
proximity
between pattern occurrences, or pattern-independent
PageRank
of the document.

The first formal framework to study such kinds of retrieval problems was given by Muthukrishnan [SODA 2002]. He considered two metrics for relevance: frequency and proximity. He took a threshold-based approach on these metrics and gave data structures that use
O
(
n
log
n
) words of space. We study this problem in a somewhat more natural top-
k
framework. Here,
k
is a part of the query, and the top
k
most relevant (highest-scoring) documents are to be reported in sorted order of score. We present the first linear-space framework (i.e., using
O
(
n
) words of space) that is capable of handling arbitrary score functions with near-optimal
O
(
p
+
k
log
k
) query time. The query time can be made optimal
O
(
p
+
k
) if sorted order is not necessary. Further, we derive compact space and succinct space indexes (for some specific score functions). This space compression comes at the cost of higher query time. At last, we extend our framework to handle the case of multiple patterns. Apart from providing a robust framework, our results also improve many earlier results in index space or query time or both.
Algorithm 940
Authors: Nelson Blake , Kirby Robert M. , Parker Steven
Published: April 2014

In this article we present a compile-time algorithm, implemented using C++ template metaprogramming techniques, that minimizes the use of temporary storage when evaluating expressions. We present the basic building blocks of our algorithm---transformations that act locally on nodes of the expression parse tree---and demonstrate that the application of these local transformations generates a (nonunique) expression that requires a minimum number of temporary storage objects to evaluate. We discuss a C++ implementation of our algorithm using expression templates, and give results demonstrating the effectiveness of our approach.
Designing for dream spaces
Authors: Warpas Kasia
Published: April 2014

This forum aims to offer and promote a rich discussion at the intersection of art, performance, and culture that expands the boundaries of HCI while broadening our understanding of how things of the past come to matter in the present.
---Elisa Giaccardi, Editor
A Retrospective Study of Ectoparasitosis in Patients Referred to Imam Reza Hospital of Mashhad, Iran
Authors: Berenji Fariba , Marvi-Moghadam Narges , Naghibozakerin Meibodi Parisa
Published: April 2014

This cross-sectional study was performed on all patients suspected to be suffering from ectoparasites who were referred to the parasitology laboratory of Imam Reza Hospital of Mashhad during 15 years (April 1995 to April 2010). All patients’ data were collected from the questionnaires and then analyzed statistically. From 1814 suspected patients to be suffering from ectoparasites, 375 patients had scabies and, 99 suffer from pediculosis. The mean age of patients was26/18±17/68. The most common age of scabies was 10–19 (27/7%) and pediculosis 0–9(9/6%) (Pvalue = 0.00). The highest incidence of pediculosis was in women (3.6%) and scabies in men (13.7%) (Pvalue = 0.00). Pediculosis is more common in children (9/9%) and scabies in workers (32%)(Pvalue = 0.00). Scabies and pediculosis were more prevalent in patients from Razavi Khorasan Province with 18.7% and 5%, respectively (Pvalue = 0.08).
Effects of Cyhalothrin-Based Pesticide on Early Life Stages of Common Carp (Cyprinus carpioL.)
Authors: Richterová Zuzana , Máchová Jana , Stará Alžběta , Tumová Jitka , Velíšek Josef , Ševčíková Marie , Svobodová Zdeňka
Published: April 2014

The effects of Nexide (a.i. gamma-cyhalothrin 60 gL-1) on cumulative mortality, growth indices, and ontogenetic development of embryos and larvae of common carp (Cyprinus carpioL.) were studied. Levels of oxidative stress parameters glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), glutathione-S-transferase (GST), and lipid peroxidation were determined. Eggs of newly fertilised common carp were exposed to Nexide at concentrations 5, 25, 50, 100, and 250 μg L-1(0.3, 1.5, 3, 6, and 15 μg L-1gamma-cyhalothrin). All organisms exposed to concentrations higher than 50 μg L-1died soon after hatching; at 25 μg L-1, 95% mortality was recorded. Larvae exposed to 5 μg L-1showed significantly lower growth and retarded ontogenetic development compared to control. Histological examination of the livers of larvae from the exposed group revealed dystrophic changes. The value of detoxification enzyme GST of organisms from the exposed group was significantly higher compared to the control and the value of defensive enzyme GPx was significantly lower compared to the control. The results of our investigation confirmed that contamination of aquatic environment by pesticides containing cyhalothrin may impair growth and development of early life stages of carp and cause disbalance of defensive enzymes.
Haemodynamic Monitoring in the Intensive Care Unit: Results from a Web-Based Swiss Survey
Authors: Siegenthaler Nils , Giraud Raphael , Saxer Till , Courvoisier Delphine S. , Romand Jacques-André , Bendjelid Karim
Published: April 2014

Background. The aim of this survey was to describe, in a situation of growing availability of monitoring devices and parameters, the practices in haemodynamic monitoring at the bedside.Methods. We conducted a Web-based survey in Swiss adult ICUs (2009-2010). The questionnaire explored the kind of monitoring used and how the fluid management was addressed.Results. Our survey included 71% of Swiss ICUs. Echocardiography (95%), pulmonary artery catheter (PAC: 85%), and transpulmonary thermodilution (TPTD) (82%) were the most commonly used. TPTD and PAC were frequently both available, although TPTD was the preferred technique. Echocardiography was widely available (95%) but seems to be rarely performed by intensivists themselves. Guidelines for the management of fluid infusion were available in 45% of ICUs. For the prediction of fluid responsiveness, intensivists rely preferentially on dynamic indices or echocardiographic parameters, but static parameters, such as central venous pressure or pulmonary artery occlusion pressure, were still used.Conclusions. In most Swiss ICUs, multiple haemodynamic monitoring devices are available, although TPTD is most commonly used. Despite the usefulness of echocardiography and its large availability, it is not widely performed by Swiss intensivists themselves. Regarding fluid management, several parameters are used without a clear consensus for the optimal method.
Prevalence and Incidence of Syphilis among Volunteer Blood Donors in Israel
Authors: Vera Leibovici , Milka Donchin , Nurith Strauss-Liviatan , Eilat Shinar
Published: April 2014

Data of 1,290,222 volunteer blood donors, in a 5-year period, was analyzed for prevalence and incidence of syphilis. Subsequent testing of donations positive in Treponema pallidum hemagglutination assay included Venereal Disease Research Laboratory and fluorescent Treponemal antibody absorption. Stepwise logistic regression model was used to identify positive syphilis serology. Prevalence of syphilis was 47 : 100,000, similar in men and women and increased significantly with age (P<0.001). Native Israelis had the lowest prevalence rate of syphilis (21 : 100,000), while a significantly higher prevalence was found among immigrants from Africa, Eastern Europe, and South America (odds ratios of 19.0, 10.8, and 7.3, resp., P<0.001 for each). About 33.2% of the seropositive donors had evidence of recent infection, and 66.8% had past infections. Incidence rate reached 8 : 100,000 person-years. Coinfection with HIV, HCV, and HBV was calculated as 8%, 1.88%, and 0.37% for positive donations, respectively. The data support the need to continue screening blood donors in Israel for syphilis and employ preventive measures to populations at risk, in order to improve public health, blood safety, and quality. A subsequent study to assess blood donors’ knowledge, attitude, and behavior is planned. In times of global migration this information may be useful to blood services worldwide.
Thicker Carotid Intima Media Thickness in Children with Monocyte Chemoattractant Protein-1: A-2138T and A-2464G Mutation
Authors: Yueniwati Yuyun , Yurina Valentina , Indra Mohammad Rasjad
Published: April 2014

Carotid intima media thickness (CIMT) is clearly associated with atherosclerosis. Studies in ischemic stroke patients reveal that there is a significant association between CIMT with monocyte chemoattractant protein-1 (MCP-1) and osteopontin (OPN) promoter polymorphism. This research aims to explain the effect of MCP-1 and OPN promoter polymorphism toward CIMT changes identified in Javanese Indonesian children. Subjects were 54 children: 27 were from parents with ischemic stroke (cases), and 27 were from healthy parents (controlled). The CIMT was examined by utilizing high resolution B-mode ultrasound. Physical examination and genotyping analysis of MCP-1 promoter were conducted by employing PCR method. Research results indicate that two polymorphisms were obtained, that is, A-2138T and G-2464A, respectively. A-2138T polymorphism was found in 5% of case children and in 14.3% of controlled children. G-2464A polymorphism was found in 5% of case children. CIMT of case children was significantly different from that of controlled children (0.61±0.012 mm versus,0.52±0.015 mm,P=0.021). Subjects with MCP-1 promoter polymorphism have 1.471 times higher tendency to have thicker CIMT than subjects with no polymorphism in MCP1 promoter. OPN promoter T-66G was also studied but it did not indicate occurrence of polymorphism in samples.
Direct Determination of Smoothing Parameter for Penalized Spline Regression
Authors: Yoshida Takuma
Published: April 2014

Penalized spline estimator is one of the useful smoothing methods. To construct the estimator, having goodness of fit and smoothness, the smoothing parameter should be appropriately selected. The purpose of this paper is to select the smoothing parameter using the asymptotic property of the penalized splines. The new smoothing parameter selection method is established in the context of minimization asymptotic form of MISE of the penalized splines. The mathematical and the numerical properties of the proposed method are studied. First we organize the new method in univariate regression model. Next we extend to the additive models. A simulation study to confirm the efficiency of the proposed method is addressed.
Analytical Modeling of Masonry Infilled RC Frames and Verification with Experimental Data
Authors: Skafida S. , Koutas L. , Bousias S. N.
Published: April 2014

The assessment of the response of masonry infilled RC frame structures has been a major challenge over the last decades. While several modeling approaches have been proposed, none can cover all aspects observed in the tests. The present paper introduces a simplified model built on the approach established by Crisafulli and Carr (2007) and addresses its calibration and implementation in a nonlinear analysis software for the evaluation of the in-plane lateral response of infilled RC frames. The proposed model uses a set of elements/springs to account separately for the compressive and shear behavior of masonry. The efficiency of the modeling approach is validated with available experimental data, yielding satisfactory matching. The most intricate issue encountered when attempting to represent a masonry panel is the plethora of the material parameters involved and the lack of complete and available test results. Thus, the numerical investigation is accompanied by a parametric study on the sensitivity of the model to the various parameters to identify the critical modeling quantities and provide guidance on their selection.
Identification of the Point Sources in Some Stochastic Wave Equations
Authors: Hu Yaozhong , Rang Guanglin
Published: April 2014

We introduce and study a type of (one-dimensional) wave equations with noisy point sources. We first study the existence and uniqueness problem of the equations. Then, we assume that the locations of point sources are unknown but we can observe the solution at some other location continuously in time. We propose an estimator to identify the point source locations and prove the convergence of our estimator.
Almost Periodic Solution of a Modified Leslie-Gower Predator-Prey Model with Beddington-DeAngelis Functional Response and Feedback Controls
Authors: Zhang Kerong , Li Jianli , Yu Aiwen
Published: April 2014

We consider a modified Leslie-Gower predator-prey model with the Beddington-DeAngelis functional response and feedback controls as follows:x˙t=xta1t-btxt-ctyt/αt+βtxt+γtyt-e1tut,u˙t=-d1tut+p1txt-τ,y˙t=yta2t-rtyt/xt+kt-e2tνt, andν˙(t)=-d2(t)ν(t)+p2(t)y(t-τ). Sufficient conditions which guarantee the permanence and existence of a unique globally attractive positive almost periodic solution of the system are obtained.
Expression and Clinical Significance of YAP, TAZ, and AREG in Hepatocellular Carcinoma
Authors: Han Su-xia , Bai E. , Jin Gui-hua , He Chen-chen , Guo Xi-jing , Wang Li-juan , Li Meng , Ying Xia , Zhu Qing
Published: April 2014

Purpose. Yes-associated protein (YAP) and PDZ-binding motif (TAZ) are two important effectors of Hippo pathway controlling the balance of organ size and carcinogenesis. Amphiregulin (AREG) is a member of the epidermal growth factor family, a direct target gene of YAP and TAZ. The role of these proteins in hepatocellular carcinoma (HCC) is unclear.Methods. The expression of YAP, TAZ, and AREG in HCC was analyzed by immunohistochemical staining. The level of secreted serum AREG was also assayed by enzyme-linked immunosorbent (ELISA) assay.Results. YAP, TAZ, and AREG were expressed in 69.2% (27/39), 66.7% (26/39), and 61.5% (24/39) of HCC patients. The expression of YAP was significantly correlated with Edmondson stage (P>0.05), serum AFP level (P>0.05), and HCC prognosis (P>0.05). AREG expression was also significantly correlated with Edmondson stage (P>0.05) and serum AFP level (P>0.05). In addition, the expression of serum AREG was higher than serum AFP in HCC patients. Further multivariate analysis showed that YAP expression was an independent prognostic factor that significantly affected the overall survival of HCC patients.Conclusions. YAP maybe an independent prognostic indicator for HCC patients and serum AREG may be a serological biomarker of HCC.